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[tor-commits] [tor/maint-0.4.0] Merge remote-tracking branch 'tor-github/pr/920' into maint-0.3.5



commit e3ba9b7a78d1c31b3b319021b983465a60864901
Merge: 519556ef2 c24928dd8
Author: teor <teor@xxxxxxxxxxxxxx>
Date:   Fri Aug 9 14:00:01 2019 +1000

    Merge remote-tracking branch 'tor-github/pr/920' into maint-0.3.5

 changes/bug30041               |  5 +++++
 src/core/mainloop/connection.c |  4 ++++
 src/lib/container/buffers.c    | 11 +++++++++--
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --cc src/core/mainloop/connection.c
index 7b8dc7f36,000000000..a6c9029da
mode 100644,000000..100644
--- a/src/core/mainloop/connection.c
+++ b/src/core/mainloop/connection.c
@@@ -1,5491 -1,0 +1,5495 @@@
 +/* Copyright (c) 2001 Matej Pfajfar.
 + * Copyright (c) 2001-2004, Roger Dingledine.
 + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
 + * Copyright (c) 2007-2019, The Tor Project, Inc. */
 +/* See LICENSE for licensing information */
 +
 +/**
 + * \file connection.c
 + * \brief General high-level functions to handle reading and writing
 + * on connections.
 + *
 + * Each connection (ideally) represents a TLS connection, a TCP socket, a unix
 + * socket, or a UDP socket on which reads and writes can occur.  (But see
 + * connection_edge.c for cases where connections can also represent streams
 + * that do not have a corresponding socket.)
 + *
 + * The module implements the abstract type, connection_t.  The subtypes are:
 + *  <ul>
 + *   <li>listener_connection_t, implemented here in connection.c
 + *   <li>dir_connection_t, implemented in directory.c
 + *   <li>or_connection_t, implemented in connection_or.c
 + *   <li>edge_connection_t, implemented in connection_edge.c, along with
 + *      its subtype(s):
 + *      <ul><li>entry_connection_t, also implemented in connection_edge.c
 + *      </ul>
 + *   <li>control_connection_t, implemented in control.c
 + *  </ul>
 + *
 + * The base type implemented in this module is responsible for basic
 + * rate limiting, flow control, and marshalling bytes onto and off of the
 + * network (either directly or via TLS).
 + *
 + * Connections are registered with the main loop with connection_add(). As
 + * they become able to read or write register the fact with the event main
 + * loop by calling connection_watch_events(), connection_start_reading(), or
 + * connection_start_writing().  When they no longer want to read or write,
 + * they call connection_stop_reading() or connection_stop_writing().
 + *
 + * To queue data to be written on a connection, call
 + * connection_buf_add().  When data arrives, the
 + * connection_process_inbuf() callback is invoked, which dispatches to a
 + * type-specific function (such as connection_edge_process_inbuf() for
 + * example). Connection types that need notice of when data has been written
 + * receive notification via connection_flushed_some() and
 + * connection_finished_flushing().  These functions all delegate to
 + * type-specific implementations.
 + *
 + * Additionally, beyond the core of connection_t, this module also implements:
 + * <ul>
 + * <li>Listeners, which wait for incoming sockets and launch connections
 + * <li>Outgoing SOCKS proxy support
 + * <li>Outgoing HTTP proxy support
 + * <li>An out-of-sockets handler for dealing with socket exhaustion
 + * </ul>
 + **/
 +
 +#define CONNECTION_PRIVATE
 +#include "core/or/or.h"
 +#include "feature/client/bridges.h"
 +#include "lib/container/buffers.h"
 +#include "lib/tls/buffers_tls.h"
 +#include "lib/err/backtrace.h"
 +
 +/*
 + * Define this so we get channel internal functions, since we're implementing
 + * part of a subclass (channel_tls_t).
 + */
 +#define TOR_CHANNEL_INTERNAL_
 +#define CONNECTION_PRIVATE
 +#include "app/config/config.h"
 +#include "core/mainloop/connection.h"
 +#include "core/mainloop/mainloop.h"
 +#include "core/mainloop/netstatus.h"
 +#include "core/or/channel.h"
 +#include "core/or/channeltls.h"
 +#include "core/or/circuitbuild.h"
 +#include "core/or/circuitlist.h"
 +#include "core/or/circuituse.h"
 +#include "core/or/connection_edge.h"
 +#include "core/or/connection_or.h"
 +#include "core/or/dos.h"
 +#include "core/or/policies.h"
 +#include "core/or/reasons.h"
 +#include "core/or/relay.h"
 +#include "core/proto/proto_http.h"
 +#include "core/proto/proto_socks.h"
 +#include "feature/client/dnsserv.h"
 +#include "feature/client/entrynodes.h"
 +#include "feature/client/transports.h"
 +#include "feature/control/control.h"
 +#include "feature/dirauth/authmode.h"
 +#include "feature/dircache/dirserv.h"
 +#include "feature/dircommon/directory.h"
 +#include "feature/hibernate/hibernate.h"
 +#include "feature/hs/hs_common.h"
 +#include "feature/hs/hs_ident.h"
 +#include "feature/nodelist/nodelist.h"
 +#include "feature/nodelist/routerlist.h"
 +#include "feature/relay/dns.h"
 +#include "feature/relay/ext_orport.h"
 +#include "feature/relay/routermode.h"
 +#include "feature/rend/rendclient.h"
 +#include "feature/rend/rendcommon.h"
 +#include "feature/stats/rephist.h"
 +#include "lib/crypt_ops/crypto_util.h"
 +#include "lib/geoip/geoip.h"
 +
 +#include "lib/sandbox/sandbox.h"
 +#include "lib/net/buffers_net.h"
 +#include "lib/tls/tortls.h"
 +#include "lib/evloop/compat_libevent.h"
 +#include "lib/compress/compress.h"
 +
 +#ifdef HAVE_PWD_H
 +#include <pwd.h>
 +#endif
 +
 +#ifdef HAVE_UNISTD_H
 +#include <unistd.h>
 +#endif
 +#ifdef HAVE_SYS_STAT_H
 +#include <sys/stat.h>
 +#endif
 +
 +#ifdef HAVE_SYS_UN_H
 +#include <sys/socket.h>
 +#include <sys/un.h>
 +#endif
 +
 +#include "feature/dircommon/dir_connection_st.h"
 +#include "feature/control/control_connection_st.h"
 +#include "core/or/entry_connection_st.h"
 +#include "core/or/listener_connection_st.h"
 +#include "core/or/or_connection_st.h"
 +#include "core/or/port_cfg_st.h"
 +#include "feature/nodelist/routerinfo_st.h"
 +#include "core/or/socks_request_st.h"
 +
 +/**
 + * On Windows and Linux we cannot reliably bind() a socket to an
 + * address and port if: 1) There's already a socket bound to wildcard
 + * address (0.0.0.0 or ::) with the same port; 2) We try to bind()
 + * to wildcard address and there's another socket bound to a
 + * specific address and the same port.
 + *
 + * To address this problem on these two platforms we implement a
 + * routine that:
 + * 1) Checks if first attempt to bind() a new socket  failed with
 + * EADDRINUSE.
 + * 2) If so, it will close the appropriate old listener connection and
 + * 3) Attempts bind()'ing the new listener socket again.
 + *
 + * Just to be safe, we are enabling listener rebind code on all platforms,
 + * to account for unexpected cases where it may be needed.
 + */
 +#define ENABLE_LISTENER_REBIND
 +
 +static connection_t *connection_listener_new(
 +                               const struct sockaddr *listensockaddr,
 +                               socklen_t listensocklen, int type,
 +                               const char *address,
 +                               const port_cfg_t *portcfg,
 +                               int *addr_in_use);
 +static connection_t *connection_listener_new_for_port(
 +                               const port_cfg_t *port,
 +                               int *defer, int *addr_in_use);
 +static void connection_init(time_t now, connection_t *conn, int type,
 +                            int socket_family);
 +static int connection_handle_listener_read(connection_t *conn, int new_type);
 +static int connection_finished_flushing(connection_t *conn);
 +static int connection_flushed_some(connection_t *conn);
 +static int connection_finished_connecting(connection_t *conn);
 +static int connection_reached_eof(connection_t *conn);
 +static int connection_buf_read_from_socket(connection_t *conn,
 +                                           ssize_t *max_to_read,
 +                                           int *socket_error);
 +static int connection_process_inbuf(connection_t *conn, int package_partial);
 +static void client_check_address_changed(tor_socket_t sock);
 +static void set_constrained_socket_buffers(tor_socket_t sock, int size);
 +
 +static const char *connection_proxy_state_to_string(int state);
 +static int connection_read_https_proxy_response(connection_t *conn);
 +static void connection_send_socks5_connect(connection_t *conn);
 +static const char *proxy_type_to_string(int proxy_type);
 +static int get_proxy_type(void);
 +const tor_addr_t *conn_get_outbound_address(sa_family_t family,
 +                  const or_options_t *options, unsigned int conn_type);
 +static void reenable_blocked_connection_init(const or_options_t *options);
 +static void reenable_blocked_connection_schedule(void);
 +
 +/** The last addresses that our network interface seemed to have been
 + * binding to.  We use this as one way to detect when our IP changes.
 + *
 + * XXXX+ We should really use the entire list of interfaces here.
 + **/
 +static tor_addr_t *last_interface_ipv4 = NULL;
 +/* DOCDOC last_interface_ipv6 */
 +static tor_addr_t *last_interface_ipv6 = NULL;
 +/** A list of tor_addr_t for addresses we've used in outgoing connections.
 + * Used to detect IP address changes. */
 +static smartlist_t *outgoing_addrs = NULL;
 +
 +#define CASE_ANY_LISTENER_TYPE \
 +    case CONN_TYPE_OR_LISTENER: \
 +    case CONN_TYPE_EXT_OR_LISTENER: \
 +    case CONN_TYPE_AP_LISTENER: \
 +    case CONN_TYPE_DIR_LISTENER: \
 +    case CONN_TYPE_CONTROL_LISTENER: \
 +    case CONN_TYPE_AP_TRANS_LISTENER: \
 +    case CONN_TYPE_AP_NATD_LISTENER: \
 +    case CONN_TYPE_AP_DNS_LISTENER: \
 +    case CONN_TYPE_AP_HTTP_CONNECT_LISTENER
 +
 +/**************************************************************/
 +
 +/** Convert a connection_t* to an listener_connection_t*; assert if the cast
 + * is invalid. */
 +listener_connection_t *
 +TO_LISTENER_CONN(connection_t *c)
 +{
 +  tor_assert(c->magic == LISTENER_CONNECTION_MAGIC);
 +  return DOWNCAST(listener_connection_t, c);
 +}
 +
 +size_t
 +connection_get_inbuf_len(connection_t *conn)
 +{
 +  return conn->inbuf ? buf_datalen(conn->inbuf) : 0;
 +}
 +
 +size_t
 +connection_get_outbuf_len(connection_t *conn)
 +{
 +    return conn->outbuf ? buf_datalen(conn->outbuf) : 0;
 +}
 +
 +/**
 + * Return the human-readable name for the connection type <b>type</b>
 + */
 +const char *
 +conn_type_to_string(int type)
 +{
 +  static char buf[64];
 +  switch (type) {
 +    case CONN_TYPE_OR_LISTENER: return "OR listener";
 +    case CONN_TYPE_OR: return "OR";
 +    case CONN_TYPE_EXIT: return "Exit";
 +    case CONN_TYPE_AP_LISTENER: return "Socks listener";
 +    case CONN_TYPE_AP_TRANS_LISTENER:
 +      return "Transparent pf/netfilter listener";
 +    case CONN_TYPE_AP_NATD_LISTENER: return "Transparent natd listener";
 +    case CONN_TYPE_AP_DNS_LISTENER: return "DNS listener";
 +    case CONN_TYPE_AP: return "Socks";
 +    case CONN_TYPE_DIR_LISTENER: return "Directory listener";
 +    case CONN_TYPE_DIR: return "Directory";
 +    case CONN_TYPE_CONTROL_LISTENER: return "Control listener";
 +    case CONN_TYPE_CONTROL: return "Control";
 +    case CONN_TYPE_EXT_OR: return "Extended OR";
 +    case CONN_TYPE_EXT_OR_LISTENER: return "Extended OR listener";
 +    case CONN_TYPE_AP_HTTP_CONNECT_LISTENER: return "HTTP tunnel listener";
 +    default:
 +      log_warn(LD_BUG, "unknown connection type %d", type);
 +      tor_snprintf(buf, sizeof(buf), "unknown [%d]", type);
 +      return buf;
 +  }
 +}
 +
 +/**
 + * Return the human-readable name for the connection state <b>state</b>
 + * for the connection type <b>type</b>
 + */
 +const char *
 +conn_state_to_string(int type, int state)
 +{
 +  static char buf[96];
 +  switch (type) {
 +    CASE_ANY_LISTENER_TYPE:
 +      if (state == LISTENER_STATE_READY)
 +        return "ready";
 +      break;
 +    case CONN_TYPE_OR:
 +      switch (state) {
 +        case OR_CONN_STATE_CONNECTING: return "connect()ing";
 +        case OR_CONN_STATE_PROXY_HANDSHAKING: return "handshaking (proxy)";
 +        case OR_CONN_STATE_TLS_HANDSHAKING: return "handshaking (TLS)";
 +        case OR_CONN_STATE_TLS_CLIENT_RENEGOTIATING:
 +          return "renegotiating (TLS, v2 handshake)";
 +        case OR_CONN_STATE_TLS_SERVER_RENEGOTIATING:
 +          return "waiting for renegotiation or V3 handshake";
 +        case OR_CONN_STATE_OR_HANDSHAKING_V2:
 +          return "handshaking (Tor, v2 handshake)";
 +        case OR_CONN_STATE_OR_HANDSHAKING_V3:
 +          return "handshaking (Tor, v3 handshake)";
 +        case OR_CONN_STATE_OPEN: return "open";
 +      }
 +      break;
 +    case CONN_TYPE_EXT_OR:
 +      switch (state) {
 +        case EXT_OR_CONN_STATE_AUTH_WAIT_AUTH_TYPE:
 +          return "waiting for authentication type";
 +        case EXT_OR_CONN_STATE_AUTH_WAIT_CLIENT_NONCE:
 +          return "waiting for client nonce";
 +        case EXT_OR_CONN_STATE_AUTH_WAIT_CLIENT_HASH:
 +          return "waiting for client hash";
 +        case EXT_OR_CONN_STATE_OPEN: return "open";
 +        case EXT_OR_CONN_STATE_FLUSHING: return "flushing final OKAY";
 +      }
 +      break;
 +    case CONN_TYPE_EXIT:
 +      switch (state) {
 +        case EXIT_CONN_STATE_RESOLVING: return "waiting for dest info";
 +        case EXIT_CONN_STATE_CONNECTING: return "connecting";
 +        case EXIT_CONN_STATE_OPEN: return "open";
 +        case EXIT_CONN_STATE_RESOLVEFAILED: return "resolve failed";
 +      }
 +      break;
 +    case CONN_TYPE_AP:
 +      switch (state) {
 +        case AP_CONN_STATE_SOCKS_WAIT: return "waiting for socks info";
 +        case AP_CONN_STATE_NATD_WAIT: return "waiting for natd dest info";
 +        case AP_CONN_STATE_RENDDESC_WAIT: return "waiting for rendezvous desc";
 +        case AP_CONN_STATE_CONTROLLER_WAIT: return "waiting for controller";
 +        case AP_CONN_STATE_CIRCUIT_WAIT: return "waiting for circuit";
 +        case AP_CONN_STATE_CONNECT_WAIT: return "waiting for connect response";
 +        case AP_CONN_STATE_RESOLVE_WAIT: return "waiting for resolve response";
 +        case AP_CONN_STATE_OPEN: return "open";
 +      }
 +      break;
 +    case CONN_TYPE_DIR:
 +      switch (state) {
 +        case DIR_CONN_STATE_CONNECTING: return "connecting";
 +        case DIR_CONN_STATE_CLIENT_SENDING: return "client sending";
 +        case DIR_CONN_STATE_CLIENT_READING: return "client reading";
 +        case DIR_CONN_STATE_CLIENT_FINISHED: return "client finished";
 +        case DIR_CONN_STATE_SERVER_COMMAND_WAIT: return "waiting for command";
 +        case DIR_CONN_STATE_SERVER_WRITING: return "writing";
 +      }
 +      break;
 +    case CONN_TYPE_CONTROL:
 +      switch (state) {
 +        case CONTROL_CONN_STATE_OPEN: return "open (protocol v1)";
 +        case CONTROL_CONN_STATE_NEEDAUTH:
 +          return "waiting for authentication (protocol v1)";
 +      }
 +      break;
 +  }
 +
 +  log_warn(LD_BUG, "unknown connection state %d (type %d)", state, type);
 +  tor_snprintf(buf, sizeof(buf),
 +               "unknown state [%d] on unknown [%s] connection",
 +               state, conn_type_to_string(type));
 +  return buf;
 +}
 +
 +/** Allocate and return a new dir_connection_t, initialized as by
 + * connection_init(). */
 +dir_connection_t *
 +dir_connection_new(int socket_family)
 +{
 +  dir_connection_t *dir_conn = tor_malloc_zero(sizeof(dir_connection_t));
 +  connection_init(time(NULL), TO_CONN(dir_conn), CONN_TYPE_DIR, socket_family);
 +  return dir_conn;
 +}
 +
 +/** Allocate and return a new or_connection_t, initialized as by
 + * connection_init().
 + *
 + * Initialize active_circuit_pqueue.
 + *
 + * Set active_circuit_pqueue_last_recalibrated to current cell_ewma tick.
 + */
 +or_connection_t *
 +or_connection_new(int type, int socket_family)
 +{
 +  or_connection_t *or_conn = tor_malloc_zero(sizeof(or_connection_t));
 +  time_t now = time(NULL);
 +  tor_assert(type == CONN_TYPE_OR || type == CONN_TYPE_EXT_OR);
 +  connection_init(now, TO_CONN(or_conn), type, socket_family);
 +
 +  connection_or_set_canonical(or_conn, 0);
 +
 +  if (type == CONN_TYPE_EXT_OR)
 +    connection_or_set_ext_or_identifier(or_conn);
 +
 +  return or_conn;
 +}
 +
 +/** Allocate and return a new entry_connection_t, initialized as by
 + * connection_init().
 + *
 + * Allocate space to store the socks_request.
 + */
 +entry_connection_t *
 +entry_connection_new(int type, int socket_family)
 +{
 +  entry_connection_t *entry_conn = tor_malloc_zero(sizeof(entry_connection_t));
 +  tor_assert(type == CONN_TYPE_AP);
 +  connection_init(time(NULL), ENTRY_TO_CONN(entry_conn), type, socket_family);
 +  entry_conn->socks_request = socks_request_new();
 +  /* If this is coming from a listener, we'll set it up based on the listener
 +   * in a little while.  Otherwise, we're doing this as a linked connection
 +   * of some kind, and we should set it up here based on the socket family */
 +  if (socket_family == AF_INET)
 +    entry_conn->entry_cfg.ipv4_traffic = 1;
 +  else if (socket_family == AF_INET6)
 +    entry_conn->entry_cfg.ipv6_traffic = 1;
 +  return entry_conn;
 +}
 +
 +/** Allocate and return a new edge_connection_t, initialized as by
 + * connection_init(). */
 +edge_connection_t *
 +edge_connection_new(int type, int socket_family)
 +{
 +  edge_connection_t *edge_conn = tor_malloc_zero(sizeof(edge_connection_t));
 +  tor_assert(type == CONN_TYPE_EXIT);
 +  connection_init(time(NULL), TO_CONN(edge_conn), type, socket_family);
 +  return edge_conn;
 +}
 +
 +/** Allocate and return a new control_connection_t, initialized as by
 + * connection_init(). */
 +control_connection_t *
 +control_connection_new(int socket_family)
 +{
 +  control_connection_t *control_conn =
 +    tor_malloc_zero(sizeof(control_connection_t));
 +  connection_init(time(NULL),
 +                  TO_CONN(control_conn), CONN_TYPE_CONTROL, socket_family);
 +  return control_conn;
 +}
 +
 +/** Allocate and return a new listener_connection_t, initialized as by
 + * connection_init(). */
 +listener_connection_t *
 +listener_connection_new(int type, int socket_family)
 +{
 +  listener_connection_t *listener_conn =
 +    tor_malloc_zero(sizeof(listener_connection_t));
 +  connection_init(time(NULL), TO_CONN(listener_conn), type, socket_family);
 +  return listener_conn;
 +}
 +
 +/** Allocate, initialize, and return a new connection_t subtype of <b>type</b>
 + * to make or receive connections of address family <b>socket_family</b>.  The
 + * type should be one of the CONN_TYPE_* constants. */
 +connection_t *
 +connection_new(int type, int socket_family)
 +{
 +  switch (type) {
 +    case CONN_TYPE_OR:
 +    case CONN_TYPE_EXT_OR:
 +      return TO_CONN(or_connection_new(type, socket_family));
 +
 +    case CONN_TYPE_EXIT:
 +      return TO_CONN(edge_connection_new(type, socket_family));
 +
 +    case CONN_TYPE_AP:
 +      return ENTRY_TO_CONN(entry_connection_new(type, socket_family));
 +
 +    case CONN_TYPE_DIR:
 +      return TO_CONN(dir_connection_new(socket_family));
 +
 +    case CONN_TYPE_CONTROL:
 +      return TO_CONN(control_connection_new(socket_family));
 +
 +    CASE_ANY_LISTENER_TYPE:
 +      return TO_CONN(listener_connection_new(type, socket_family));
 +
 +    default: {
 +      connection_t *conn = tor_malloc_zero(sizeof(connection_t));
 +      connection_init(time(NULL), conn, type, socket_family);
 +      return conn;
 +    }
 +  }
 +}
 +
 +/** Initializes conn. (you must call connection_add() to link it into the main
 + * array).
 + *
 + * Set conn-\>magic to the correct value.
 + *
 + * Set conn-\>type to <b>type</b>. Set conn-\>s and conn-\>conn_array_index to
 + * -1 to signify they are not yet assigned.
 + *
 + * Initialize conn's timestamps to now.
 + */
 +static void
 +connection_init(time_t now, connection_t *conn, int type, int socket_family)
 +{
 +  static uint64_t n_connections_allocated = 1;
 +
 +  switch (type) {
 +    case CONN_TYPE_OR:
 +    case CONN_TYPE_EXT_OR:
 +      conn->magic = OR_CONNECTION_MAGIC;
 +      break;
 +    case CONN_TYPE_EXIT:
 +      conn->magic = EDGE_CONNECTION_MAGIC;
 +      break;
 +    case CONN_TYPE_AP:
 +      conn->magic = ENTRY_CONNECTION_MAGIC;
 +      break;
 +    case CONN_TYPE_DIR:
 +      conn->magic = DIR_CONNECTION_MAGIC;
 +      break;
 +    case CONN_TYPE_CONTROL:
 +      conn->magic = CONTROL_CONNECTION_MAGIC;
 +      break;
 +    CASE_ANY_LISTENER_TYPE:
 +      conn->magic = LISTENER_CONNECTION_MAGIC;
 +      break;
 +    default:
 +      conn->magic = BASE_CONNECTION_MAGIC;
 +      break;
 +  }
 +
 +  conn->s = TOR_INVALID_SOCKET; /* give it a default of 'not used' */
 +  conn->conn_array_index = -1; /* also default to 'not used' */
 +  conn->global_identifier = n_connections_allocated++;
 +
 +  conn->type = type;
 +  conn->socket_family = socket_family;
 +  if (!connection_is_listener(conn)) {
 +    /* listeners never use their buf */
 +    conn->inbuf = buf_new();
 +    conn->outbuf = buf_new();
 +  }
 +
 +  conn->timestamp_created = now;
 +  conn->timestamp_last_read_allowed = now;
 +  conn->timestamp_last_write_allowed = now;
 +}
 +
 +/** Create a link between <b>conn_a</b> and <b>conn_b</b>. */
 +void
 +connection_link_connections(connection_t *conn_a, connection_t *conn_b)
 +{
 +  tor_assert(! SOCKET_OK(conn_a->s));
 +  tor_assert(! SOCKET_OK(conn_b->s));
 +
 +  conn_a->linked = 1;
 +  conn_b->linked = 1;
 +  conn_a->linked_conn = conn_b;
 +  conn_b->linked_conn = conn_a;
 +}
 +
 +/** Return true iff the provided connection listener type supports AF_UNIX
 + * sockets. */
 +int
 +conn_listener_type_supports_af_unix(int type)
 +{
 +  /* For now only control ports or SOCKS ports can be Unix domain sockets
 +   * and listeners at the same time */
 +  switch (type) {
 +    case CONN_TYPE_CONTROL_LISTENER:
 +    case CONN_TYPE_AP_LISTENER:
 +      return 1;
 +    default:
 +      return 0;
 +  }
 +}
 +
 +/** Deallocate memory used by <b>conn</b>. Deallocate its buffers if
 + * necessary, close its socket if necessary, and mark the directory as dirty
 + * if <b>conn</b> is an OR or OP connection.
 + */
 +STATIC void
 +connection_free_minimal(connection_t *conn)
 +{
 +  void *mem;
 +  size_t memlen;
 +  if (!conn)
 +    return;
 +
 +  switch (conn->type) {
 +    case CONN_TYPE_OR:
 +    case CONN_TYPE_EXT_OR:
 +      tor_assert(conn->magic == OR_CONNECTION_MAGIC);
 +      mem = TO_OR_CONN(conn);
 +      memlen = sizeof(or_connection_t);
 +      break;
 +    case CONN_TYPE_AP:
 +      tor_assert(conn->magic == ENTRY_CONNECTION_MAGIC);
 +      mem = TO_ENTRY_CONN(conn);
 +      memlen = sizeof(entry_connection_t);
 +      break;
 +    case CONN_TYPE_EXIT:
 +      tor_assert(conn->magic == EDGE_CONNECTION_MAGIC);
 +      mem = TO_EDGE_CONN(conn);
 +      memlen = sizeof(edge_connection_t);
 +      break;
 +    case CONN_TYPE_DIR:
 +      tor_assert(conn->magic == DIR_CONNECTION_MAGIC);
 +      mem = TO_DIR_CONN(conn);
 +      memlen = sizeof(dir_connection_t);
 +      break;
 +    case CONN_TYPE_CONTROL:
 +      tor_assert(conn->magic == CONTROL_CONNECTION_MAGIC);
 +      mem = TO_CONTROL_CONN(conn);
 +      memlen = sizeof(control_connection_t);
 +      break;
 +    CASE_ANY_LISTENER_TYPE:
 +      tor_assert(conn->magic == LISTENER_CONNECTION_MAGIC);
 +      mem = TO_LISTENER_CONN(conn);
 +      memlen = sizeof(listener_connection_t);
 +      break;
 +    default:
 +      tor_assert(conn->magic == BASE_CONNECTION_MAGIC);
 +      mem = conn;
 +      memlen = sizeof(connection_t);
 +      break;
 +  }
 +
 +  if (conn->linked) {
 +    log_info(LD_GENERAL, "Freeing linked %s connection [%s] with %d "
 +             "bytes on inbuf, %d on outbuf.",
 +             conn_type_to_string(conn->type),
 +             conn_state_to_string(conn->type, conn->state),
 +             (int)connection_get_inbuf_len(conn),
 +             (int)connection_get_outbuf_len(conn));
 +  }
 +
 +  if (!connection_is_listener(conn)) {
 +    buf_free(conn->inbuf);
 +    buf_free(conn->outbuf);
 +  } else {
 +    if (conn->socket_family == AF_UNIX) {
 +      /* For now only control and SOCKS ports can be Unix domain sockets
 +       * and listeners at the same time */
 +      tor_assert(conn_listener_type_supports_af_unix(conn->type));
 +
 +      if (unlink(conn->address) < 0 && errno != ENOENT) {
 +        log_warn(LD_NET, "Could not unlink %s: %s", conn->address,
 +                         strerror(errno));
 +      }
 +    }
 +  }
 +
 +  tor_free(conn->address);
 +
 +  if (connection_speaks_cells(conn)) {
 +    or_connection_t *or_conn = TO_OR_CONN(conn);
 +    if (or_conn->tls) {
 +      if (! SOCKET_OK(conn->s)) {
 +        /* The socket has been closed by somebody else; we must tell the
 +         * TLS object not to close it. */
 +        tor_tls_release_socket(or_conn->tls);
 +      } else {
 +        /* The tor_tls_free() call below will close the socket; we must tell
 +         * the code below not to close it a second time. */
 +        tor_release_socket_ownership(conn->s);
 +        conn->s = TOR_INVALID_SOCKET;
 +      }
 +      tor_tls_free(or_conn->tls);
 +      or_conn->tls = NULL;
 +    }
 +    or_handshake_state_free(or_conn->handshake_state);
 +    or_conn->handshake_state = NULL;
 +    tor_free(or_conn->nickname);
 +    if (or_conn->chan) {
 +      /* Owww, this shouldn't happen, but... */
 +      channel_t *base_chan = TLS_CHAN_TO_BASE(or_conn->chan);
 +      tor_assert(base_chan);
 +      log_info(LD_CHANNEL,
 +               "Freeing orconn at %p, saw channel %p with ID "
 +               "%"PRIu64 " left un-NULLed",
 +               or_conn, base_chan,
 +               base_chan->global_identifier);
 +      if (!CHANNEL_FINISHED(base_chan)) {
 +        channel_close_for_error(base_chan);
 +      }
 +
 +      or_conn->chan->conn = NULL;
 +      or_conn->chan = NULL;
 +    }
 +  }
 +  if (conn->type == CONN_TYPE_AP) {
 +    entry_connection_t *entry_conn = TO_ENTRY_CONN(conn);
 +    tor_free(entry_conn->chosen_exit_name);
 +    tor_free(entry_conn->original_dest_address);
 +    if (entry_conn->socks_request)
 +      socks_request_free(entry_conn->socks_request);
 +    if (entry_conn->pending_optimistic_data) {
 +      buf_free(entry_conn->pending_optimistic_data);
 +    }
 +    if (entry_conn->sending_optimistic_data) {
 +      buf_free(entry_conn->sending_optimistic_data);
 +    }
 +  }
 +  if (CONN_IS_EDGE(conn)) {
 +    rend_data_free(TO_EDGE_CONN(conn)->rend_data);
 +    hs_ident_edge_conn_free(TO_EDGE_CONN(conn)->hs_ident);
 +  }
 +  if (conn->type == CONN_TYPE_CONTROL) {
 +    control_connection_t *control_conn = TO_CONTROL_CONN(conn);
 +    tor_free(control_conn->safecookie_client_hash);
 +    tor_free(control_conn->incoming_cmd);
 +    if (control_conn->ephemeral_onion_services) {
 +      SMARTLIST_FOREACH(control_conn->ephemeral_onion_services, char *, cp, {
 +        memwipe(cp, 0, strlen(cp));
 +        tor_free(cp);
 +      });
 +      smartlist_free(control_conn->ephemeral_onion_services);
 +    }
 +  }
 +
 +  /* Probably already freed by connection_free. */
 +  tor_event_free(conn->read_event);
 +  tor_event_free(conn->write_event);
 +  conn->read_event = conn->write_event = NULL;
 +
 +  if (conn->type == CONN_TYPE_DIR) {
 +    dir_connection_t *dir_conn = TO_DIR_CONN(conn);
 +    tor_free(dir_conn->requested_resource);
 +
 +    tor_compress_free(dir_conn->compress_state);
 +    if (dir_conn->spool) {
 +      SMARTLIST_FOREACH(dir_conn->spool, spooled_resource_t *, spooled,
 +                        spooled_resource_free(spooled));
 +      smartlist_free(dir_conn->spool);
 +    }
 +
 +    rend_data_free(dir_conn->rend_data);
 +    hs_ident_dir_conn_free(dir_conn->hs_ident);
 +    if (dir_conn->guard_state) {
 +      /* Cancel before freeing, if it's still there. */
 +      entry_guard_cancel(&dir_conn->guard_state);
 +    }
 +    circuit_guard_state_free(dir_conn->guard_state);
 +  }
 +
 +  if (SOCKET_OK(conn->s)) {
 +    log_debug(LD_NET,"closing fd %d.",(int)conn->s);
 +    tor_close_socket(conn->s);
 +    conn->s = TOR_INVALID_SOCKET;
 +  }
 +
 +  if (conn->type == CONN_TYPE_OR &&
 +      !tor_digest_is_zero(TO_OR_CONN(conn)->identity_digest)) {
 +    log_warn(LD_BUG, "called on OR conn with non-zeroed identity_digest");
 +    connection_or_clear_identity(TO_OR_CONN(conn));
 +  }
 +  if (conn->type == CONN_TYPE_OR || conn->type == CONN_TYPE_EXT_OR) {
 +    connection_or_remove_from_ext_or_id_map(TO_OR_CONN(conn));
 +    tor_free(TO_OR_CONN(conn)->ext_or_conn_id);
 +    tor_free(TO_OR_CONN(conn)->ext_or_auth_correct_client_hash);
 +    tor_free(TO_OR_CONN(conn)->ext_or_transport);
 +  }
 +
 +  memwipe(mem, 0xCC, memlen); /* poison memory */
 +  tor_free(mem);
 +}
 +
 +/** Make sure <b>conn</b> isn't in any of the global conn lists; then free it.
 + */
 +MOCK_IMPL(void,
 +connection_free_,(connection_t *conn))
 +{
 +  if (!conn)
 +    return;
 +  tor_assert(!connection_is_on_closeable_list(conn));
 +  tor_assert(!connection_in_array(conn));
 +  if (BUG(conn->linked_conn)) {
 +    conn->linked_conn->linked_conn = NULL;
 +    if (! conn->linked_conn->marked_for_close &&
 +        conn->linked_conn->reading_from_linked_conn)
 +      connection_start_reading(conn->linked_conn);
 +    conn->linked_conn = NULL;
 +  }
 +  if (connection_speaks_cells(conn)) {
 +    if (!tor_digest_is_zero(TO_OR_CONN(conn)->identity_digest)) {
 +      connection_or_clear_identity(TO_OR_CONN(conn));
 +    }
 +  }
 +  if (conn->type == CONN_TYPE_CONTROL) {
 +    connection_control_closed(TO_CONTROL_CONN(conn));
 +  }
 +#if 1
 +  /* DEBUGGING */
 +  if (conn->type == CONN_TYPE_AP) {
 +    connection_ap_warn_and_unmark_if_pending_circ(TO_ENTRY_CONN(conn),
 +                                                  "connection_free");
 +  }
 +#endif /* 1 */
 +
 +  /* Notify the circuit creation DoS mitigation subsystem that an OR client
 +   * connection has been closed. And only do that if we track it. */
 +  if (conn->type == CONN_TYPE_OR) {
 +    dos_close_client_conn(TO_OR_CONN(conn));
 +  }
 +
 +  connection_unregister_events(conn);
 +  connection_free_minimal(conn);
 +}
 +
 +/**
 + * Called when we're about to finally unlink and free a connection:
 + * perform necessary accounting and cleanup
 + *   - Directory conns that failed to fetch a rendezvous descriptor
 + *     need to inform pending rendezvous streams.
 + *   - OR conns need to call rep_hist_note_*() to record status.
 + *   - AP conns need to send a socks reject if necessary.
 + *   - Exit conns need to call connection_dns_remove() if necessary.
 + *   - AP and Exit conns need to send an end cell if they can.
 + *   - DNS conns need to fail any resolves that are pending on them.
 + *   - OR and edge connections need to be unlinked from circuits.
 + */
 +void
 +connection_about_to_close_connection(connection_t *conn)
 +{
 +  tor_assert(conn->marked_for_close);
 +
 +  switch (conn->type) {
 +    case CONN_TYPE_DIR:
 +      connection_dir_about_to_close(TO_DIR_CONN(conn));
 +      break;
 +    case CONN_TYPE_OR:
 +    case CONN_TYPE_EXT_OR:
 +      connection_or_about_to_close(TO_OR_CONN(conn));
 +      break;
 +    case CONN_TYPE_AP:
 +      connection_ap_about_to_close(TO_ENTRY_CONN(conn));
 +      break;
 +    case CONN_TYPE_EXIT:
 +      connection_exit_about_to_close(TO_EDGE_CONN(conn));
 +      break;
 +  }
 +}
 +
 +/** Return true iff connection_close_immediate() has been called on this
 + * connection. */
 +#define CONN_IS_CLOSED(c) \
 +  ((c)->linked ? ((c)->linked_conn_is_closed) : (! SOCKET_OK(c->s)))
 +
 +/** Close the underlying socket for <b>conn</b>, so we don't try to
 + * flush it. Must be used in conjunction with (right before)
 + * connection_mark_for_close().
 + */
 +void
 +connection_close_immediate(connection_t *conn)
 +{
 +  assert_connection_ok(conn,0);
 +  if (CONN_IS_CLOSED(conn)) {
 +    log_err(LD_BUG,"Attempt to close already-closed connection.");
 +    tor_fragile_assert();
 +    return;
 +  }
 +  if (conn->outbuf_flushlen) {
 +    log_info(LD_NET,"fd %d, type %s, state %s, %d bytes on outbuf.",
 +             (int)conn->s, conn_type_to_string(conn->type),
 +             conn_state_to_string(conn->type, conn->state),
 +             (int)conn->outbuf_flushlen);
 +  }
 +
 +  connection_unregister_events(conn);
 +
 +  /* Prevent the event from getting unblocked. */
 +  conn->read_blocked_on_bw = 0;
 +  conn->write_blocked_on_bw = 0;
 +
 +  if (SOCKET_OK(conn->s))
 +    tor_close_socket(conn->s);
 +  conn->s = TOR_INVALID_SOCKET;
 +  if (conn->linked)
 +    conn->linked_conn_is_closed = 1;
 +  if (conn->outbuf)
 +    buf_clear(conn->outbuf);
 +  conn->outbuf_flushlen = 0;
 +}
 +
 +/** Mark <b>conn</b> to be closed next time we loop through
 + * conn_close_if_marked() in main.c. */
 +void
 +connection_mark_for_close_(connection_t *conn, int line, const char *file)
 +{
 +  assert_connection_ok(conn,0);
 +  tor_assert(line);
 +  tor_assert(line < 1<<16); /* marked_for_close can only fit a uint16_t. */
 +  tor_assert(file);
 +
 +  if (conn->type == CONN_TYPE_OR) {
 +    /*
 +     * An or_connection should have been closed through one of the channel-
 +     * aware functions in connection_or.c.  We'll assume this is an error
 +     * close and do that, and log a bug warning.
 +     */
 +    log_warn(LD_CHANNEL | LD_BUG,
 +             "Something tried to close an or_connection_t without going "
 +             "through channels at %s:%d",
 +             file, line);
 +    connection_or_close_for_error(TO_OR_CONN(conn), 0);
 +  } else {
 +    /* Pass it down to the real function */
 +    connection_mark_for_close_internal_(conn, line, file);
 +  }
 +}
 +
 +/** Mark <b>conn</b> to be closed next time we loop through
 + * conn_close_if_marked() in main.c; the _internal version bypasses the
 + * CONN_TYPE_OR checks; this should be called when you either are sure that
 + * if this is an or_connection_t the controlling channel has been notified
 + * (e.g. with connection_or_notify_error()), or you actually are the
 + * connection_or_close_for_error() or connection_or_close_normally() function.
 + * For all other cases, use connection_mark_and_flush() instead, which
 + * checks for or_connection_t properly, instead.  See below.
 + */
 +MOCK_IMPL(void,
 +connection_mark_for_close_internal_, (connection_t *conn,
 +                                      int line, const char *file))
 +{
 +  assert_connection_ok(conn,0);
 +  tor_assert(line);
 +  tor_assert(line < 1<<16); /* marked_for_close can only fit a uint16_t. */
 +  tor_assert(file);
 +
 +  if (conn->marked_for_close) {
 +    log_warn(LD_BUG,"Duplicate call to connection_mark_for_close at %s:%d"
 +        " (first at %s:%d)", file, line, conn->marked_for_close_file,
 +        conn->marked_for_close);
 +    tor_fragile_assert();
 +    return;
 +  }
 +
 +  if (conn->type == CONN_TYPE_OR) {
 +    /*
 +     * Bad news if this happens without telling the controlling channel; do
 +     * this so we can find things that call this wrongly when the asserts hit.
 +     */
 +    log_debug(LD_CHANNEL,
 +              "Calling connection_mark_for_close_internal_() on an OR conn "
 +              "at %s:%d",
 +              file, line);
 +  }
 +
 +  conn->marked_for_close = line;
 +  conn->marked_for_close_file = file;
 +  add_connection_to_closeable_list(conn);
 +
 +  /* in case we're going to be held-open-til-flushed, reset
 +   * the number of seconds since last successful write, so
 +   * we get our whole 15 seconds */
 +  conn->timestamp_last_write_allowed = time(NULL);
 +}
 +
 +/** Find each connection that has hold_open_until_flushed set to
 + * 1 but hasn't written in the past 15 seconds, and set
 + * hold_open_until_flushed to 0. This means it will get cleaned
 + * up in the next loop through close_if_marked() in main.c.
 + */
 +void
 +connection_expire_held_open(void)
 +{
 +  time_t now;
 +  smartlist_t *conns = get_connection_array();
 +
 +  now = time(NULL);
 +
 +  SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn) {
 +    /* If we've been holding the connection open, but we haven't written
 +     * for 15 seconds...
 +     */
 +    if (conn->hold_open_until_flushed) {
 +      tor_assert(conn->marked_for_close);
 +      if (now - conn->timestamp_last_write_allowed >= 15) {
 +        int severity;
 +        if (conn->type == CONN_TYPE_EXIT ||
 +            (conn->type == CONN_TYPE_DIR &&
 +             conn->purpose == DIR_PURPOSE_SERVER))
 +          severity = LOG_INFO;
 +        else
 +          severity = LOG_NOTICE;
 +        log_fn(severity, LD_NET,
 +               "Giving up on marked_for_close conn that's been flushing "
 +               "for 15s (fd %d, type %s, state %s).",
 +               (int)conn->s, conn_type_to_string(conn->type),
 +               conn_state_to_string(conn->type, conn->state));
 +        conn->hold_open_until_flushed = 0;
 +      }
 +    }
 +  } SMARTLIST_FOREACH_END(conn);
 +}
 +
 +#if defined(HAVE_SYS_UN_H) || defined(RUNNING_DOXYGEN)
 +/** Create an AF_UNIX listenaddr struct.
 + * <b>listenaddress</b> provides the path to the Unix socket.
 + *
 + * Eventually <b>listenaddress</b> will also optionally contain user, group,
 + * and file permissions for the new socket.  But not yet. XXX
 + * Also, since we do not create the socket here the information doesn't help
 + * here.
 + *
 + * If not NULL <b>readable_address</b> will contain a copy of the path part of
 + * <b>listenaddress</b>.
 + *
 + * The listenaddr struct has to be freed by the caller.
 + */
 +static struct sockaddr_un *
 +create_unix_sockaddr(const char *listenaddress, char **readable_address,
 +                     socklen_t *len_out)
 +{
 +  struct sockaddr_un *sockaddr = NULL;
 +
 +  sockaddr = tor_malloc_zero(sizeof(struct sockaddr_un));
 +  sockaddr->sun_family = AF_UNIX;
 +  if (strlcpy(sockaddr->sun_path, listenaddress, sizeof(sockaddr->sun_path))
 +      >= sizeof(sockaddr->sun_path)) {
 +    log_warn(LD_CONFIG, "Unix socket path '%s' is too long to fit.",
 +             escaped(listenaddress));
 +    tor_free(sockaddr);
 +    return NULL;
 +  }
 +
 +  if (readable_address)
 +    *readable_address = tor_strdup(listenaddress);
 +
 +  *len_out = sizeof(struct sockaddr_un);
 +  return sockaddr;
 +}
 +#else /* !(defined(HAVE_SYS_UN_H) || defined(RUNNING_DOXYGEN)) */
 +static struct sockaddr *
 +create_unix_sockaddr(const char *listenaddress, char **readable_address,
 +                     socklen_t *len_out)
 +{
 +  (void)listenaddress;
 +  (void)readable_address;
 +  log_fn(LOG_ERR, LD_BUG,
 +         "Unix domain sockets not supported, yet we tried to create one.");
 +  *len_out = 0;
 +  tor_fragile_assert();
 +  return NULL;
 +}
 +#endif /* defined(HAVE_SYS_UN_H) || defined(RUNNING_DOXYGEN) */
 +
 +/** Warn that an accept or a connect has failed because we're running out of
 + * TCP sockets we can use on current system.  Rate-limit these warnings so
 + * that we don't spam the log. */
 +static void
 +warn_too_many_conns(void)
 +{
 +#define WARN_TOO_MANY_CONNS_INTERVAL (6*60*60)
 +  static ratelim_t last_warned = RATELIM_INIT(WARN_TOO_MANY_CONNS_INTERVAL);
 +  char *m;
 +  if ((m = rate_limit_log(&last_warned, approx_time()))) {
 +    int n_conns = get_n_open_sockets();
 +    log_warn(LD_NET,"Failing because we have %d connections already. Please "
 +             "read doc/TUNING for guidance.%s", n_conns, m);
 +    tor_free(m);
 +    control_event_general_status(LOG_WARN, "TOO_MANY_CONNECTIONS CURRENT=%d",
 +                                 n_conns);
 +  }
 +}
 +
 +#ifdef HAVE_SYS_UN_H
 +
 +#define UNIX_SOCKET_PURPOSE_CONTROL_SOCKET 0
 +#define UNIX_SOCKET_PURPOSE_SOCKS_SOCKET 1
 +
 +/** Check if the purpose isn't one of the ones we know what to do with */
 +
 +static int
 +is_valid_unix_socket_purpose(int purpose)
 +{
 +  int valid = 0;
 +
 +  switch (purpose) {
 +    case UNIX_SOCKET_PURPOSE_CONTROL_SOCKET:
 +    case UNIX_SOCKET_PURPOSE_SOCKS_SOCKET:
 +      valid = 1;
 +      break;
 +  }
 +
 +  return valid;
 +}
 +
 +/** Return a string description of a unix socket purpose */
 +static const char *
 +unix_socket_purpose_to_string(int purpose)
 +{
 +  const char *s = "unknown-purpose socket";
 +
 +  switch (purpose) {
 +    case UNIX_SOCKET_PURPOSE_CONTROL_SOCKET:
 +      s = "control socket";
 +      break;
 +    case UNIX_SOCKET_PURPOSE_SOCKS_SOCKET:
 +      s = "SOCKS socket";
 +      break;
 +  }
 +
 +  return s;
 +}
 +
 +/** Check whether we should be willing to open an AF_UNIX socket in
 + * <b>path</b>.  Return 0 if we should go ahead and -1 if we shouldn't. */
 +static int
 +check_location_for_unix_socket(const or_options_t *options, const char *path,
 +                               int purpose, const port_cfg_t *port)
 +{
 +  int r = -1;
 +  char *p = NULL;
 +
 +  tor_assert(is_valid_unix_socket_purpose(purpose));
 +
 +  p = tor_strdup(path);
 +  cpd_check_t flags = CPD_CHECK_MODE_ONLY;
 +  if (get_parent_directory(p)<0 || p[0] != '/') {
 +    log_warn(LD_GENERAL, "Bad unix socket address '%s'.  Tor does not support "
 +             "relative paths for unix sockets.", path);
 +    goto done;
 +  }
 +
 +  if (port->is_world_writable) {
 +    /* World-writable sockets can go anywhere. */
 +    r = 0;
 +    goto done;
 +  }
 +
 +  if (port->is_group_writable) {
 +    flags |= CPD_GROUP_OK;
 +  }
 +
 +  if (port->relax_dirmode_check) {
 +    flags |= CPD_RELAX_DIRMODE_CHECK;
 +  }
 +
 +  if (check_private_dir(p, flags, options->User) < 0) {
 +    char *escpath, *escdir;
 +    escpath = esc_for_log(path);
 +    escdir = esc_for_log(p);
 +    log_warn(LD_GENERAL, "Before Tor can create a %s in %s, the directory "
 +             "%s needs to exist, and to be accessible only by the user%s "
 +             "account that is running Tor.  (On some Unix systems, anybody "
 +             "who can list a socket can connect to it, so Tor is being "
 +             "careful.)",
 +             unix_socket_purpose_to_string(purpose), escpath, escdir,
 +             port->is_group_writable ? " and group" : "");
 +    tor_free(escpath);
 +    tor_free(escdir);
 +    goto done;
 +  }
 +
 +  r = 0;
 + done:
 +  tor_free(p);
 +  return r;
 +}
 +#endif /* defined(HAVE_SYS_UN_H) */
 +
 +/** Tell the TCP stack that it shouldn't wait for a long time after
 + * <b>sock</b> has closed before reusing its port. Return 0 on success,
 + * -1 on failure. */
 +static int
 +make_socket_reuseable(tor_socket_t sock)
 +{
 +#ifdef _WIN32
 +  (void) sock;
 +  return 0;
 +#else
 +  int one=1;
 +
 +  /* REUSEADDR on normal places means you can rebind to the port
 +   * right after somebody else has let it go. But REUSEADDR on win32
 +   * means you can bind to the port _even when somebody else
 +   * already has it bound_. So, don't do that on Win32. */
 +  if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void*) &one,
 +             (socklen_t)sizeof(one)) == -1) {
 +    return -1;
 +  }
 +  return 0;
 +#endif /* defined(_WIN32) */
 +}
 +
 +#ifdef _WIN32
 +/** Tell the Windows TCP stack to prevent other applications from receiving
 + * traffic from tor's open ports. Return 0 on success, -1 on failure. */
 +static int
 +make_win32_socket_exclusive(tor_socket_t sock)
 +{
 +#ifdef SO_EXCLUSIVEADDRUSE
 +  int one=1;
 +
 +  /* Any socket that sets REUSEADDR on win32 can bind to a port _even when
 +   * somebody else already has it bound_, and _even if the original socket
 +   * didn't set REUSEADDR_. Use EXCLUSIVEADDRUSE to prevent this port-stealing
 +   * on win32. */
 +  if (setsockopt(sock, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (void*) &one,
 +                 (socklen_t)sizeof(one))) {
 +    return -1;
 +  }
 +  return 0;
 +#else /* !(defined(SO_EXCLUSIVEADDRUSE)) */
 +  (void) sock;
 +  return 0;
 +#endif /* defined(SO_EXCLUSIVEADDRUSE) */
 +}
 +#endif /* defined(_WIN32) */
 +
 +/** Max backlog to pass to listen.  We start at */
 +static int listen_limit = INT_MAX;
 +
 +/* Listen on <b>fd</b> with appropriate backlog. Return as for listen. */
 +static int
 +tor_listen(tor_socket_t fd)
 +{
 +  int r;
 +
 +  if ((r = listen(fd, listen_limit)) < 0) {
 +    if (listen_limit == SOMAXCONN)
 +      return r;
 +    if ((r = listen(fd, SOMAXCONN)) == 0) {
 +      listen_limit = SOMAXCONN;
 +      log_warn(LD_NET, "Setting listen backlog to INT_MAX connections "
 +               "didn't work, but SOMAXCONN did. Lowering backlog limit.");
 +    }
 +  }
 +  return r;
 +}
 +
 +/** Bind a new non-blocking socket listening to the socket described
 + * by <b>listensockaddr</b>.
 + *
 + * <b>address</b> is only used for logging purposes and to add the information
 + * to the conn.
 + *
 + * Set <b>addr_in_use</b> to true in case socket binding fails with
 + * EADDRINUSE.
 + */
 +static connection_t *
 +connection_listener_new(const struct sockaddr *listensockaddr,
 +                        socklen_t socklen,
 +                        int type, const char *address,
 +                        const port_cfg_t *port_cfg,
 +                        int *addr_in_use)
 +{
 +  listener_connection_t *lis_conn;
 +  connection_t *conn = NULL;
 +  tor_socket_t s = TOR_INVALID_SOCKET;  /* the socket we're going to make */
 +  or_options_t const *options = get_options();
 +  (void) options; /* Windows doesn't use this. */
 +#if defined(HAVE_PWD_H) && defined(HAVE_SYS_UN_H)
 +  const struct passwd *pw = NULL;
 +#endif
 +  uint16_t usePort = 0, gotPort = 0;
 +  int start_reading = 0;
 +  static int global_next_session_group = SESSION_GROUP_FIRST_AUTO;
 +  tor_addr_t addr;
 +  int exhaustion = 0;
 +
 +  if (addr_in_use)
 +    *addr_in_use = 0;
 +
 +  if (listensockaddr->sa_family == AF_INET ||
 +      listensockaddr->sa_family == AF_INET6) {
 +    int is_stream = (type != CONN_TYPE_AP_DNS_LISTENER);
 +    if (is_stream)
 +      start_reading = 1;
 +
 +    tor_addr_from_sockaddr(&addr, listensockaddr, &usePort);
 +    log_notice(LD_NET, "Opening %s on %s",
 +               conn_type_to_string(type), fmt_addrport(&addr, usePort));
 +
 +    s = tor_open_socket_nonblocking(tor_addr_family(&addr),
 +      is_stream ? SOCK_STREAM : SOCK_DGRAM,
 +      is_stream ? IPPROTO_TCP: IPPROTO_UDP);
 +    if (!SOCKET_OK(s)) {
 +      int e = tor_socket_errno(s);
 +      if (ERRNO_IS_RESOURCE_LIMIT(e)) {
 +        warn_too_many_conns();
 +        /*
 +         * We'll call the OOS handler at the error exit, so set the
 +         * exhaustion flag for it.
 +         */
 +        exhaustion = 1;
 +      } else {
 +        log_warn(LD_NET, "Socket creation failed: %s",
 +                 tor_socket_strerror(e));
 +      }
 +      goto err;
 +    }
 +
 +    if (make_socket_reuseable(s) < 0) {
 +      log_warn(LD_NET, "Error setting SO_REUSEADDR flag on %s: %s",
 +               conn_type_to_string(type),
 +               tor_socket_strerror(errno));
 +    }
 +
 +#ifdef _WIN32
 +    if (make_win32_socket_exclusive(s) < 0) {
 +      log_warn(LD_NET, "Error setting SO_EXCLUSIVEADDRUSE flag on %s: %s",
 +               conn_type_to_string(type),
 +               tor_socket_strerror(errno));
 +    }
 +#endif /* defined(_WIN32) */
 +
 +#if defined(USE_TRANSPARENT) && defined(IP_TRANSPARENT)
 +    if (options->TransProxyType_parsed == TPT_TPROXY &&
 +        type == CONN_TYPE_AP_TRANS_LISTENER) {
 +      int one = 1;
 +      if (setsockopt(s, SOL_IP, IP_TRANSPARENT, (void*)&one,
 +                     (socklen_t)sizeof(one)) < 0) {
 +        const char *extra = "";
 +        int e = tor_socket_errno(s);
 +        if (e == EPERM)
 +          extra = "TransTPROXY requires root privileges or similar"
 +            " capabilities.";
 +        log_warn(LD_NET, "Error setting IP_TRANSPARENT flag: %s.%s",
 +                 tor_socket_strerror(e), extra);
 +      }
 +    }
 +#endif /* defined(USE_TRANSPARENT) && defined(IP_TRANSPARENT) */
 +
 +#ifdef IPV6_V6ONLY
 +    if (listensockaddr->sa_family == AF_INET6) {
 +      int one = 1;
 +      /* We need to set IPV6_V6ONLY so that this socket can't get used for
 +       * IPv4 connections. */
 +      if (setsockopt(s,IPPROTO_IPV6, IPV6_V6ONLY,
 +                     (void*)&one, (socklen_t)sizeof(one)) < 0) {
 +        int e = tor_socket_errno(s);
 +        log_warn(LD_NET, "Error setting IPV6_V6ONLY flag: %s",
 +                 tor_socket_strerror(e));
 +        /* Keep going; probably not harmful. */
 +      }
 +    }
 +#endif /* defined(IPV6_V6ONLY) */
 +
 +    if (bind(s,listensockaddr,socklen) < 0) {
 +      const char *helpfulhint = "";
 +      int e = tor_socket_errno(s);
 +      if (ERRNO_IS_EADDRINUSE(e)) {
 +        helpfulhint = ". Is Tor already running?";
 +        if (addr_in_use)
 +          *addr_in_use = 1;
 +      }
 +      log_warn(LD_NET, "Could not bind to %s:%u: %s%s", address, usePort,
 +               tor_socket_strerror(e), helpfulhint);
 +      goto err;
 +    }
 +
 +    if (is_stream) {
 +      if (tor_listen(s) < 0) {
 +        log_warn(LD_NET, "Could not listen on %s:%u: %s", address, usePort,
 +                 tor_socket_strerror(tor_socket_errno(s)));
 +        goto err;
 +      }
 +    }
 +
 +    if (usePort != 0) {
 +      gotPort = usePort;
 +    } else {
 +      tor_addr_t addr2;
 +      struct sockaddr_storage ss;
 +      socklen_t ss_len=sizeof(ss);
 +      if (getsockname(s, (struct sockaddr*)&ss, &ss_len)<0) {
 +        log_warn(LD_NET, "getsockname() couldn't learn address for %s: %s",
 +                 conn_type_to_string(type),
 +                 tor_socket_strerror(tor_socket_errno(s)));
 +        gotPort = 0;
 +      }
 +      tor_addr_from_sockaddr(&addr2, (struct sockaddr*)&ss, &gotPort);
 +    }
 +#ifdef HAVE_SYS_UN_H
 +  /*
 +   * AF_UNIX generic setup stuff
 +   */
 +  } else if (listensockaddr->sa_family == AF_UNIX) {
 +    /* We want to start reading for both AF_UNIX cases */
 +    start_reading = 1;
 +
 +    tor_assert(conn_listener_type_supports_af_unix(type));
 +
 +    if (check_location_for_unix_socket(options, address,
 +          (type == CONN_TYPE_CONTROL_LISTENER) ?
 +           UNIX_SOCKET_PURPOSE_CONTROL_SOCKET :
 +           UNIX_SOCKET_PURPOSE_SOCKS_SOCKET, port_cfg) < 0) {
 +        goto err;
 +    }
 +
 +    log_notice(LD_NET, "Opening %s on %s",
 +               conn_type_to_string(type), address);
 +
 +    tor_addr_make_unspec(&addr);
 +
 +    if (unlink(address) < 0 && errno != ENOENT) {
 +      log_warn(LD_NET, "Could not unlink %s: %s", address,
 +                       strerror(errno));
 +      goto err;
 +    }
 +
 +    s = tor_open_socket_nonblocking(AF_UNIX, SOCK_STREAM, 0);
 +    if (! SOCKET_OK(s)) {
 +      int e = tor_socket_errno(s);
 +      if (ERRNO_IS_RESOURCE_LIMIT(e)) {
 +        warn_too_many_conns();
 +        /*
 +         * We'll call the OOS handler at the error exit, so set the
 +         * exhaustion flag for it.
 +         */
 +        exhaustion = 1;
 +      } else {
 +        log_warn(LD_NET,"Socket creation failed: %s.", strerror(e));
 +      }
 +      goto err;
 +    }
 +
 +    if (bind(s, listensockaddr,
 +             (socklen_t)sizeof(struct sockaddr_un)) == -1) {
 +      log_warn(LD_NET,"Bind to %s failed: %s.", address,
 +               tor_socket_strerror(tor_socket_errno(s)));
 +      goto err;
 +    }
 +
 +#ifdef HAVE_PWD_H
 +    if (options->User) {
 +      pw = tor_getpwnam(options->User);
 +      struct stat st;
 +      if (pw == NULL) {
 +        log_warn(LD_NET,"Unable to chown() %s socket: user %s not found.",
 +                 address, options->User);
 +        goto err;
 +      } else if (fstat(s, &st) == 0 &&
 +                 st.st_uid == pw->pw_uid && st.st_gid == pw->pw_gid) {
 +        /* No change needed */
 +      } else if (chown(sandbox_intern_string(address),
 +                       pw->pw_uid, pw->pw_gid) < 0) {
 +        log_warn(LD_NET,"Unable to chown() %s socket: %s.",
 +                 address, strerror(errno));
 +        goto err;
 +      }
 +    }
 +#endif /* defined(HAVE_PWD_H) */
 +
 +    {
 +      unsigned mode;
 +      const char *status;
 +      struct stat st;
 +      if (port_cfg->is_world_writable) {
 +        mode = 0666;
 +        status = "world-writable";
 +      } else if (port_cfg->is_group_writable) {
 +        mode = 0660;
 +        status = "group-writable";
 +      } else {
 +        mode = 0600;
 +        status = "private";
 +      }
 +      /* We need to use chmod; fchmod doesn't work on sockets on all
 +       * platforms. */
 +      if (fstat(s, &st) == 0 && (st.st_mode & 0777) == mode) {
 +        /* no change needed */
 +      } else if (chmod(sandbox_intern_string(address), mode) < 0) {
 +        log_warn(LD_FS,"Unable to make %s %s.", address, status);
 +        goto err;
 +      }
 +    }
 +
 +    if (listen(s, SOMAXCONN) < 0) {
 +      log_warn(LD_NET, "Could not listen on %s: %s", address,
 +               tor_socket_strerror(tor_socket_errno(s)));
 +      goto err;
 +    }
 +#endif /* defined(HAVE_SYS_UN_H) */
 +  } else {
 +    log_err(LD_BUG, "Got unexpected address family %d.",
 +            listensockaddr->sa_family);
 +    tor_assert(0);
 +  }
 +
 +  lis_conn = listener_connection_new(type, listensockaddr->sa_family);
 +  conn = TO_CONN(lis_conn);
 +  conn->socket_family = listensockaddr->sa_family;
 +  conn->s = s;
 +  s = TOR_INVALID_SOCKET; /* Prevent double-close */
 +  conn->address = tor_strdup(address);
 +  conn->port = gotPort;
 +  tor_addr_copy(&conn->addr, &addr);
 +
 +  memcpy(&lis_conn->entry_cfg, &port_cfg->entry_cfg, sizeof(entry_port_cfg_t));
 +
 +  if (port_cfg->entry_cfg.isolation_flags) {
 +    lis_conn->entry_cfg.isolation_flags = port_cfg->entry_cfg.isolation_flags;
 +    if (port_cfg->entry_cfg.session_group >= 0) {
 +      lis_conn->entry_cfg.session_group = port_cfg->entry_cfg.session_group;
 +    } else {
 +      /* This can wrap after around INT_MAX listeners are opened.  But I don't
 +       * believe that matters, since you would need to open a ridiculous
 +       * number of listeners while keeping the early ones open before you ever
 +       * hit this.  An OR with a dozen ports open, for example, would have to
 +       * close and re-open its listeners every second for 4 years nonstop.
 +       */
 +      lis_conn->entry_cfg.session_group = global_next_session_group--;
 +    }
 +  }
 +
 +  if (type != CONN_TYPE_AP_LISTENER) {
 +    lis_conn->entry_cfg.ipv4_traffic = 1;
 +    lis_conn->entry_cfg.ipv6_traffic = 1;
 +    lis_conn->entry_cfg.prefer_ipv6 = 0;
 +  }
 +
 +  if (connection_add(conn) < 0) { /* no space, forget it */
 +    log_warn(LD_NET,"connection_add for listener failed. Giving up.");
 +    goto err;
 +  }
 +
 +  log_fn(usePort==gotPort ? LOG_DEBUG : LOG_NOTICE, LD_NET,
 +         "%s listening on port %u.",
 +         conn_type_to_string(type), gotPort);
 +
 +  conn->state = LISTENER_STATE_READY;
 +  if (start_reading) {
 +    connection_start_reading(conn);
 +  } else {
 +    tor_assert(type == CONN_TYPE_AP_DNS_LISTENER);
 +    dnsserv_configure_listener(conn);
 +  }
 +
 +  /*
 +   * Normal exit; call the OOS handler since connection count just changed;
 +   * the exhaustion flag will always be zero here though.
 +   */
 +  connection_check_oos(get_n_open_sockets(), 0);
 +
 +  if (conn->socket_family == AF_UNIX) {
 +    log_notice(LD_NET, "Opened %s on %s",
 +               conn_type_to_string(type), conn->address);
 +  } else {
 +    log_notice(LD_NET, "Opened %s on %s",
 +               conn_type_to_string(type), fmt_addrport(&addr, gotPort));
 +  }
 +  return conn;
 +
 + err:
 +  if (SOCKET_OK(s))
 +    tor_close_socket(s);
 +  if (conn)
 +    connection_free(conn);
 +
 +  /* Call the OOS handler, indicate if we saw an exhaustion-related error */
 +  connection_check_oos(get_n_open_sockets(), exhaustion);
 +
 +  return NULL;
 +}
 +
 +/**
 + * Create a new listener connection for a given <b>port</b>. In case we
 + * for a reason that is not an error condition, set <b>defer</b>
 + * to true. If we cannot bind listening socket because address is already
 + * in use, set <b>addr_in_use</b> to true.
 + */
 +static connection_t *
 +connection_listener_new_for_port(const port_cfg_t *port,
 +                                 int *defer, int *addr_in_use)
 +{
 +  connection_t *conn;
 +  struct sockaddr *listensockaddr;
 +  socklen_t listensocklen = 0;
 +  char *address=NULL;
 +  int real_port = port->port == CFG_AUTO_PORT ? 0 : port->port;
 +  tor_assert(real_port <= UINT16_MAX);
 +
 +  if (defer)
 +    *defer = 0;
 +
 +  if (port->server_cfg.no_listen) {
 +    if (defer)
 +      *defer = 1;
 +    return NULL;
 +  }
 +
 +#ifndef _WIN32
 +  /* We don't need to be root to create a UNIX socket, so defer until after
 +   * setuid. */
 +  const or_options_t *options = get_options();
 +  if (port->is_unix_addr && !geteuid() && (options->User) &&
 +      strcmp(options->User, "root")) {
 +    if (defer)
 +      *defer = 1;
 +    return NULL;
 +  }
 +#endif /* !defined(_WIN32) */
 +
 +  if (port->is_unix_addr) {
 +    listensockaddr = (struct sockaddr *)
 +      create_unix_sockaddr(port->unix_addr,
 +                           &address, &listensocklen);
 +  } else {
 +    listensockaddr = tor_malloc(sizeof(struct sockaddr_storage));
 +    listensocklen = tor_addr_to_sockaddr(&port->addr,
 +                                         real_port,
 +                                         listensockaddr,
 +                                         sizeof(struct sockaddr_storage));
 +    address = tor_addr_to_str_dup(&port->addr);
 +  }
 +
 +  if (listensockaddr) {
 +    conn = connection_listener_new(listensockaddr, listensocklen,
 +                                   port->type, address, port,
 +                                   addr_in_use);
 +    tor_free(listensockaddr);
 +    tor_free(address);
 +  } else {
 +    conn = NULL;
 +  }
 +
 +  return conn;
 +}
 +
 +/** Do basic sanity checking on a newly received socket. Return 0
 + * if it looks ok, else return -1.
 + *
 + * Notably, some TCP stacks can erroneously have accept() return successfully
 + * with socklen 0, when the client sends an RST before the accept call (as
 + * nmap does).  We want to detect that, and not go on with the connection.
 + */
 +static int
 +check_sockaddr(const struct sockaddr *sa, int len, int level)
 +{
 +  int ok = 1;
 +
 +  if (sa->sa_family == AF_INET) {
 +    struct sockaddr_in *sin=(struct sockaddr_in*)sa;
 +    if (len != sizeof(struct sockaddr_in)) {
 +      log_fn(level, LD_NET, "Length of address not as expected: %d vs %d",
 +             len,(int)sizeof(struct sockaddr_in));
 +      ok = 0;
 +    }
 +    if (sin->sin_addr.s_addr == 0 || sin->sin_port == 0) {
 +      log_fn(level, LD_NET,
 +             "Address for new connection has address/port equal to zero.");
 +      ok = 0;
 +    }
 +  } else if (sa->sa_family == AF_INET6) {
 +    struct sockaddr_in6 *sin6=(struct sockaddr_in6*)sa;
 +    if (len != sizeof(struct sockaddr_in6)) {
 +      log_fn(level, LD_NET, "Length of address not as expected: %d vs %d",
 +             len,(int)sizeof(struct sockaddr_in6));
 +      ok = 0;
 +    }
 +    if (tor_mem_is_zero((void*)sin6->sin6_addr.s6_addr, 16) ||
 +        sin6->sin6_port == 0) {
 +      log_fn(level, LD_NET,
 +             "Address for new connection has address/port equal to zero.");
 +      ok = 0;
 +    }
 +  } else if (sa->sa_family == AF_UNIX) {
 +    ok = 1;
 +  } else {
 +    ok = 0;
 +  }
 +  return ok ? 0 : -1;
 +}
 +
 +/** Check whether the socket family from an accepted socket <b>got</b> is the
 + * same as the one that <b>listener</b> is waiting for.  If it isn't, log
 + * a useful message and return -1.  Else return 0.
 + *
 + * This is annoying, but can apparently happen on some Darwins. */
 +static int
 +check_sockaddr_family_match(sa_family_t got, connection_t *listener)
 +{
 +  if (got != listener->socket_family) {
 +    log_info(LD_BUG, "A listener connection returned a socket with a "
 +             "mismatched family. %s for addr_family %d gave us a socket "
 +             "with address family %d.  Dropping.",
 +             conn_type_to_string(listener->type),
 +             (int)listener->socket_family,
 +             (int)got);
 +    return -1;
 +  }
 +  return 0;
 +}
 +
 +/** The listener connection <b>conn</b> told poll() it wanted to read.
 + * Call accept() on conn-\>s, and add the new connection if necessary.
 + */
 +static int
 +connection_handle_listener_read(connection_t *conn, int new_type)
 +{
 +  tor_socket_t news; /* the new socket */
 +  connection_t *newconn = 0;
 +  /* information about the remote peer when connecting to other routers */
 +  struct sockaddr_storage addrbuf;
 +  struct sockaddr *remote = (struct sockaddr*)&addrbuf;
 +  /* length of the remote address. Must be whatever accept() needs. */
 +  socklen_t remotelen = (socklen_t)sizeof(addrbuf);
 +  const or_options_t *options = get_options();
 +
 +  tor_assert((size_t)remotelen >= sizeof(struct sockaddr_in));
 +  memset(&addrbuf, 0, sizeof(addrbuf));
 +
 +  news = tor_accept_socket_nonblocking(conn->s,remote,&remotelen);
 +  if (!SOCKET_OK(news)) { /* accept() error */
 +    int e = tor_socket_errno(conn->s);
 +    if (ERRNO_IS_ACCEPT_EAGAIN(e)) {
 +      /*
 +       * they hung up before we could accept(). that's fine.
 +       *
 +       * give the OOS handler a chance to run though
 +       */
 +      connection_check_oos(get_n_open_sockets(), 0);
 +      return 0;
 +    } else if (ERRNO_IS_RESOURCE_LIMIT(e)) {
 +      warn_too_many_conns();
 +      /* Exhaustion; tell the OOS handler */
 +      connection_check_oos(get_n_open_sockets(), 1);
 +      return 0;
 +    }
 +    /* else there was a real error. */
 +    log_warn(LD_NET,"accept() failed: %s. Closing listener.",
 +             tor_socket_strerror(e));
 +    connection_mark_for_close(conn);
 +    /* Tell the OOS handler about this too */
 +    connection_check_oos(get_n_open_sockets(), 0);
 +    return -1;
 +  }
 +  log_debug(LD_NET,
 +            "Connection accepted on socket %d (child of fd %d).",
 +            (int)news,(int)conn->s);
 +
 +  /* We accepted a new conn; run OOS handler */
 +  connection_check_oos(get_n_open_sockets(), 0);
 +
 +  if (make_socket_reuseable(news) < 0) {
 +    if (tor_socket_errno(news) == EINVAL) {
 +      /* This can happen on OSX if we get a badly timed shutdown. */
 +      log_debug(LD_NET, "make_socket_reuseable returned EINVAL");
 +    } else {
 +      log_warn(LD_NET, "Error setting SO_REUSEADDR flag on %s: %s",
 +               conn_type_to_string(new_type),
 +               tor_socket_strerror(errno));
 +    }
 +    tor_close_socket(news);
 +    return 0;
 +  }
 +
 +  if (options->ConstrainedSockets)
 +    set_constrained_socket_buffers(news, (int)options->ConstrainedSockSize);
 +
 +  if (check_sockaddr_family_match(remote->sa_family, conn) < 0) {
 +    tor_close_socket(news);
 +    return 0;
 +  }
 +
 +  if (conn->socket_family == AF_INET || conn->socket_family == AF_INET6 ||
 +     (conn->socket_family == AF_UNIX && new_type == CONN_TYPE_AP)) {
 +    tor_addr_t addr;
 +    uint16_t port;
 +    if (check_sockaddr(remote, remotelen, LOG_INFO)<0) {
 +      log_info(LD_NET,
 +               "accept() returned a strange address; closing connection.");
 +      tor_close_socket(news);
 +      return 0;
 +    }
 +
 +    tor_addr_from_sockaddr(&addr, remote, &port);
 +
 +    /* process entrance policies here, before we even create the connection */
 +    if (new_type == CONN_TYPE_AP) {
 +      /* check sockspolicy to see if we should accept it */
 +      if (socks_policy_permits_address(&addr) == 0) {
 +        log_notice(LD_APP,
 +                   "Denying socks connection from untrusted address %s.",
 +                   fmt_and_decorate_addr(&addr));
 +        tor_close_socket(news);
 +        return 0;
 +      }
 +    }
 +    if (new_type == CONN_TYPE_DIR) {
 +      /* check dirpolicy to see if we should accept it */
 +      if (dir_policy_permits_address(&addr) == 0) {
 +        log_notice(LD_DIRSERV,"Denying dir connection from address %s.",
 +                   fmt_and_decorate_addr(&addr));
 +        tor_close_socket(news);
 +        return 0;
 +      }
 +    }
 +    if (new_type == CONN_TYPE_OR) {
 +      /* Assess with the connection DoS mitigation subsystem if this address
 +       * can open a new connection. */
 +      if (dos_conn_addr_get_defense_type(&addr) == DOS_CONN_DEFENSE_CLOSE) {
 +        tor_close_socket(news);
 +        return 0;
 +      }
 +    }
 +
 +    newconn = connection_new(new_type, conn->socket_family);
 +    newconn->s = news;
 +
 +    /* remember the remote address */
 +    tor_addr_copy(&newconn->addr, &addr);
 +    if (new_type == CONN_TYPE_AP && conn->socket_family == AF_UNIX) {
 +      newconn->port = 0;
 +      newconn->address = tor_strdup(conn->address);
 +    } else {
 +      newconn->port = port;
 +      newconn->address = tor_addr_to_str_dup(&addr);
 +    }
 +
 +    if (new_type == CONN_TYPE_AP && conn->socket_family != AF_UNIX) {
 +      log_info(LD_NET, "New SOCKS connection opened from %s.",
 +               fmt_and_decorate_addr(&addr));
 +    }
 +    if (new_type == CONN_TYPE_AP && conn->socket_family == AF_UNIX) {
 +      log_info(LD_NET, "New SOCKS AF_UNIX connection opened");
 +    }
 +    if (new_type == CONN_TYPE_CONTROL) {
 +      log_notice(LD_CONTROL, "New control connection opened from %s.",
 +                 fmt_and_decorate_addr(&addr));
 +    }
 +
 +  } else if (conn->socket_family == AF_UNIX && conn->type != CONN_TYPE_AP) {
 +    tor_assert(conn->type == CONN_TYPE_CONTROL_LISTENER);
 +    tor_assert(new_type == CONN_TYPE_CONTROL);
 +    log_notice(LD_CONTROL, "New control connection opened.");
 +
 +    newconn = connection_new(new_type, conn->socket_family);
 +    newconn->s = news;
 +
 +    /* remember the remote address -- do we have anything sane to put here? */
 +    tor_addr_make_unspec(&newconn->addr);
 +    newconn->port = 1;
 +    newconn->address = tor_strdup(conn->address);
 +  } else {
 +    tor_assert(0);
 +  };
 +
 +  if (connection_add(newconn) < 0) { /* no space, forget it */
 +    connection_free(newconn);
 +    return 0; /* no need to tear down the parent */
 +  }
 +
 +  if (connection_init_accepted_conn(newconn, TO_LISTENER_CONN(conn)) < 0) {
 +    if (! newconn->marked_for_close)
 +      connection_mark_for_close(newconn);
 +    return 0;
 +  }
 +  return 0;
 +}
 +
 +/** Initialize states for newly accepted connection <b>conn</b>.
 + *
 + * If conn is an OR, start the TLS handshake.
 + *
 + * If conn is a transparent AP, get its original destination
 + * and place it in circuit_wait.
 + *
 + * The <b>listener</b> parameter is only used for AP connections.
 + */
 +int
 +connection_init_accepted_conn(connection_t *conn,
 +                              const listener_connection_t *listener)
 +{
 +  int rv;
 +
 +  connection_start_reading(conn);
 +
 +  switch (conn->type) {
 +    case CONN_TYPE_EXT_OR:
 +      /* Initiate Extended ORPort authentication. */
 +      return connection_ext_or_start_auth(TO_OR_CONN(conn));
 +    case CONN_TYPE_OR:
 +      control_event_or_conn_status(TO_OR_CONN(conn), OR_CONN_EVENT_NEW, 0);
 +      rv = connection_tls_start_handshake(TO_OR_CONN(conn), 1);
 +      if (rv < 0) {
 +        connection_or_close_for_error(TO_OR_CONN(conn), 0);
 +      }
 +      return rv;
 +      break;
 +    case CONN_TYPE_AP:
 +      memcpy(&TO_ENTRY_CONN(conn)->entry_cfg, &listener->entry_cfg,
 +             sizeof(entry_port_cfg_t));
 +      TO_ENTRY_CONN(conn)->nym_epoch = get_signewnym_epoch();
 +      TO_ENTRY_CONN(conn)->socks_request->listener_type = listener->base_.type;
 +
 +      switch (TO_CONN(listener)->type) {
 +        case CONN_TYPE_AP_LISTENER:
 +          conn->state = AP_CONN_STATE_SOCKS_WAIT;
 +          TO_ENTRY_CONN(conn)->socks_request->socks_prefer_no_auth =
 +            listener->entry_cfg.socks_prefer_no_auth;
 +          break;
 +        case CONN_TYPE_AP_TRANS_LISTENER:
 +          TO_ENTRY_CONN(conn)->is_transparent_ap = 1;
 +          /* XXXX028 -- is this correct still, with the addition of
 +           * pending_entry_connections ? */
 +          conn->state = AP_CONN_STATE_CIRCUIT_WAIT;
 +          return connection_ap_process_transparent(TO_ENTRY_CONN(conn));
 +        case CONN_TYPE_AP_NATD_LISTENER:
 +          TO_ENTRY_CONN(conn)->is_transparent_ap = 1;
 +          conn->state = AP_CONN_STATE_NATD_WAIT;
 +          break;
 +        case CONN_TYPE_AP_HTTP_CONNECT_LISTENER:
 +          conn->state = AP_CONN_STATE_HTTP_CONNECT_WAIT;
 +      }
 +      break;
 +    case CONN_TYPE_DIR:
 +      conn->purpose = DIR_PURPOSE_SERVER;
 +      conn->state = DIR_CONN_STATE_SERVER_COMMAND_WAIT;
 +      break;
 +    case CONN_TYPE_CONTROL:
 +      conn->state = CONTROL_CONN_STATE_NEEDAUTH;
 +      break;
 +  }
 +  return 0;
 +}
 +
 +/** Take conn, make a nonblocking socket; try to connect to
 + * sa, binding to bindaddr if sa is not localhost. If fail, return -1 and if
 + * applicable put your best guess about errno into *<b>socket_error</b>.
 + * If connected return 1, if EAGAIN return 0.
 + */
 +MOCK_IMPL(STATIC int,
 +connection_connect_sockaddr,(connection_t *conn,
 +                            const struct sockaddr *sa,
 +                            socklen_t sa_len,
 +                            const struct sockaddr *bindaddr,
 +                            socklen_t bindaddr_len,
 +                            int *socket_error))
 +{
 +  tor_socket_t s;
 +  int inprogress = 0;
 +  const or_options_t *options = get_options();
 +
 +  tor_assert(conn);
 +  tor_assert(sa);
 +  tor_assert(socket_error);
 +
 +  if (net_is_completely_disabled()) {
 +    /* We should never even try to connect anyplace if the network is
 +     * completely shut off.
 +     *
 +     * (We don't check net_is_disabled() here, since we still sometimes
 +     * want to open connections when we're in soft hibernation.)
 +     */
 +    static ratelim_t disablenet_violated = RATELIM_INIT(30*60);
 +    *socket_error = SOCK_ERRNO(ENETUNREACH);
 +    log_fn_ratelim(&disablenet_violated, LOG_WARN, LD_BUG,
 +                   "Tried to open a socket with DisableNetwork set.");
 +    tor_fragile_assert();
 +    return -1;
 +  }
 +
 +  const int protocol_family = sa->sa_family;
 +  const int proto = (sa->sa_family == AF_INET6 ||
 +                     sa->sa_family == AF_INET) ? IPPROTO_TCP : 0;
 +
 +  s = tor_open_socket_nonblocking(protocol_family, SOCK_STREAM, proto);
 +  if (! SOCKET_OK(s)) {
 +    /*
 +     * Early OOS handler calls; it matters if it's an exhaustion-related
 +     * error or not.
 +     */
 +    *socket_error = tor_socket_errno(s);
 +    if (ERRNO_IS_RESOURCE_LIMIT(*socket_error)) {
 +      warn_too_many_conns();
 +      connection_check_oos(get_n_open_sockets(), 1);
 +    } else {
 +      log_warn(LD_NET,"Error creating network socket: %s",
 +               tor_socket_strerror(*socket_error));
 +      connection_check_oos(get_n_open_sockets(), 0);
 +    }
 +    return -1;
 +  }
 +
 +  if (make_socket_reuseable(s) < 0) {
 +    log_warn(LD_NET, "Error setting SO_REUSEADDR flag on new connection: %s",
 +             tor_socket_strerror(errno));
 +  }
 +
 +  /*
 +   * We've got the socket open; give the OOS handler a chance to check
 +   * against configured maximum socket number, but tell it no exhaustion
 +   * failure.
 +   */
 +  connection_check_oos(get_n_open_sockets(), 0);
 +
 +  if (bindaddr && bind(s, bindaddr, bindaddr_len) < 0) {
 +    *socket_error = tor_socket_errno(s);
 +    log_warn(LD_NET,"Error binding network socket: %s",
 +             tor_socket_strerror(*socket_error));
 +    tor_close_socket(s);
 +    return -1;
 +  }
 +
 +  tor_assert(options);
 +  if (options->ConstrainedSockets)
 +    set_constrained_socket_buffers(s, (int)options->ConstrainedSockSize);
 +
 +  if (connect(s, sa, sa_len) < 0) {
 +    int e = tor_socket_errno(s);
 +    if (!ERRNO_IS_CONN_EINPROGRESS(e)) {
 +      /* yuck. kill it. */
 +      *socket_error = e;
 +      log_info(LD_NET,
 +               "connect() to socket failed: %s",
 +               tor_socket_strerror(e));
 +      tor_close_socket(s);
 +      return -1;
 +    } else {
 +      inprogress = 1;
 +    }
 +  }
 +
 +  /* it succeeded. we're connected. */
 +  log_fn(inprogress ? LOG_DEBUG : LOG_INFO, LD_NET,
 +         "Connection to socket %s (sock "TOR_SOCKET_T_FORMAT").",
 +         inprogress ? "in progress" : "established", s);
 +  conn->s = s;
 +  if (connection_add_connecting(conn) < 0) {
 +    /* no space, forget it */
 +    *socket_error = SOCK_ERRNO(ENOBUFS);
 +    return -1;
 +  }
 +
 +  return inprogress ? 0 : 1;
 +}
 +
 +/* Log a message if connection attempt is made when IPv4 or IPv6 is disabled.
 + * Log a less severe message if we couldn't conform to ClientPreferIPv6ORPort
 + * or ClientPreferIPv6ORPort. */
 +static void
 +connection_connect_log_client_use_ip_version(const connection_t *conn)
 +{
 +  const or_options_t *options = get_options();
 +
 +  /* Only clients care about ClientUseIPv4/6, bail out early on servers, and
 +   * on connections we don't care about */
 +  if (server_mode(options) || !conn || conn->type == CONN_TYPE_EXIT) {
 +    return;
 +  }
 +
 +  /* We're only prepared to log OR and DIR connections here */
 +  if (conn->type != CONN_TYPE_OR && conn->type != CONN_TYPE_DIR) {
 +    return;
 +  }
 +
 +  const int must_ipv4 = !fascist_firewall_use_ipv6(options);
 +  const int must_ipv6 = (options->ClientUseIPv4 == 0);
 +  const int pref_ipv6 = (conn->type == CONN_TYPE_OR
 +                         ? fascist_firewall_prefer_ipv6_orport(options)
 +                         : fascist_firewall_prefer_ipv6_dirport(options));
 +  tor_addr_t real_addr;
 +  tor_addr_make_null(&real_addr, AF_UNSPEC);
 +
 +  /* OR conns keep the original address in real_addr, as addr gets overwritten
 +   * with the descriptor address */
 +  if (conn->type == CONN_TYPE_OR) {
 +    const or_connection_t *or_conn = TO_OR_CONN((connection_t *)conn);
 +    tor_addr_copy(&real_addr, &or_conn->real_addr);
 +  } else if (conn->type == CONN_TYPE_DIR) {
 +    tor_addr_copy(&real_addr, &conn->addr);
 +  }
 +
 +  /* Check if we broke a mandatory address family restriction */
 +  if ((must_ipv4 && tor_addr_family(&real_addr) == AF_INET6)
 +      || (must_ipv6 && tor_addr_family(&real_addr) == AF_INET)) {
 +    static int logged_backtrace = 0;
 +    log_info(LD_BUG, "Outgoing %s connection to %s violated ClientUseIPv%s 0.",
 +             conn->type == CONN_TYPE_OR ? "OR" : "Dir",
 +             fmt_addr(&real_addr),
 +             options->ClientUseIPv4 == 0 ? "4" : "6");
 +    if (!logged_backtrace) {
 +      log_backtrace(LOG_INFO, LD_BUG, "Address came from");
 +      logged_backtrace = 1;
 +    }
 +  }
 +
 +  /* Bridges are allowed to break IPv4/IPv6 ORPort preferences to connect to
 +   * the node's configured address when ClientPreferIPv6ORPort is auto */
 +  if (options->UseBridges && conn->type == CONN_TYPE_OR
 +      && options->ClientPreferIPv6ORPort == -1) {
 +    return;
 +  }
 +
 +  /* Check if we couldn't satisfy an address family preference */
 +  if ((!pref_ipv6 && tor_addr_family(&real_addr) == AF_INET6)
 +      || (pref_ipv6 && tor_addr_family(&real_addr) == AF_INET)) {
 +    log_info(LD_NET, "Outgoing connection to %s doesn't satisfy "
 +             "ClientPreferIPv6%sPort %d, with ClientUseIPv4 %d, and "
 +             "fascist_firewall_use_ipv6 %d (ClientUseIPv6 %d and UseBridges "
 +             "%d).",
 +             fmt_addr(&real_addr),
 +             conn->type == CONN_TYPE_OR ? "OR" : "Dir",
 +             conn->type == CONN_TYPE_OR ? options->ClientPreferIPv6ORPort
 +                                        : options->ClientPreferIPv6DirPort,
 +             options->ClientUseIPv4, fascist_firewall_use_ipv6(options),
 +             options->ClientUseIPv6, options->UseBridges);
 +  }
 +}
 +
 +/** Retrieve the outbound address depending on the protocol (IPv4 or IPv6)
 + * and the connection type (relay, exit, ...)
 + * Return a socket address or NULL in case nothing is configured.
 + **/
 +const tor_addr_t *
 +conn_get_outbound_address(sa_family_t family,
 +             const or_options_t *options, unsigned int conn_type)
 +{
 +  const tor_addr_t *ext_addr = NULL;
 +
 +  int fam_index;
 +  switch (family) {
 +    case AF_INET:
 +      fam_index = 0;
 +      break;
 +    case AF_INET6:
 +      fam_index = 1;
 +      break;
 +    default:
 +      return NULL;
 +  }
 +
 +  // If an exit connection, use the exit address (if present)
 +  if (conn_type == CONN_TYPE_EXIT) {
 +    if (!tor_addr_is_null(
 +        &options->OutboundBindAddresses[OUTBOUND_ADDR_EXIT][fam_index])) {
 +      ext_addr = &options->OutboundBindAddresses[OUTBOUND_ADDR_EXIT]
 +                 [fam_index];
 +    } else if (!tor_addr_is_null(
 +                 &options->OutboundBindAddresses[OUTBOUND_ADDR_EXIT_AND_OR]
 +                 [fam_index])) {
 +      ext_addr = &options->OutboundBindAddresses[OUTBOUND_ADDR_EXIT_AND_OR]
 +                 [fam_index];
 +    }
 +  } else { // All non-exit connections
 +    if (!tor_addr_is_null(
 +           &options->OutboundBindAddresses[OUTBOUND_ADDR_OR][fam_index])) {
 +      ext_addr = &options->OutboundBindAddresses[OUTBOUND_ADDR_OR]
 +                 [fam_index];
 +    } else if (!tor_addr_is_null(
 +                 &options->OutboundBindAddresses[OUTBOUND_ADDR_EXIT_AND_OR]
 +                 [fam_index])) {
 +      ext_addr = &options->OutboundBindAddresses[OUTBOUND_ADDR_EXIT_AND_OR]
 +                 [fam_index];
 +    }
 +  }
 +  return ext_addr;
 +}
 +
 +/** Take conn, make a nonblocking socket; try to connect to
 + * addr:port (port arrives in *host order*). If fail, return -1 and if
 + * applicable put your best guess about errno into *<b>socket_error</b>.
 + * Else assign s to conn-\>s: if connected return 1, if EAGAIN return 0.
 + *
 + * addr:port can be different to conn->addr:conn->port if connecting through
 + * a proxy.
 + *
 + * address is used to make the logs useful.
 + *
 + * On success, add conn to the list of polled connections.
 + */
 +int
 +connection_connect(connection_t *conn, const char *address,
 +                   const tor_addr_t *addr, uint16_t port, int *socket_error)
 +{
 +  struct sockaddr_storage addrbuf;
 +  struct sockaddr_storage bind_addr_ss;
 +  struct sockaddr *bind_addr = NULL;
 +  struct sockaddr *dest_addr;
 +  int dest_addr_len, bind_addr_len = 0;
 +
 +  /* Log if we didn't stick to ClientUseIPv4/6 or ClientPreferIPv6OR/DirPort
 +   */
 +  connection_connect_log_client_use_ip_version(conn);
 +
 +  if (!tor_addr_is_loopback(addr)) {
 +    const tor_addr_t *ext_addr = NULL;
 +    ext_addr = conn_get_outbound_address(tor_addr_family(addr), get_options(),
 +                                         conn->type);
 +    if (ext_addr) {
 +      memset(&bind_addr_ss, 0, sizeof(bind_addr_ss));
 +      bind_addr_len = tor_addr_to_sockaddr(ext_addr, 0,
 +                                           (struct sockaddr *) &bind_addr_ss,
 +                                           sizeof(bind_addr_ss));
 +      if (bind_addr_len == 0) {
 +        log_warn(LD_NET,
 +                 "Error converting OutboundBindAddress %s into sockaddr. "
 +                 "Ignoring.", fmt_and_decorate_addr(ext_addr));
 +      } else {
 +        bind_addr = (struct sockaddr *)&bind_addr_ss;
 +      }
 +    }
 +  }
 +
 +  memset(&addrbuf,0,sizeof(addrbuf));
 +  dest_addr = (struct sockaddr*) &addrbuf;
 +  dest_addr_len = tor_addr_to_sockaddr(addr, port, dest_addr, sizeof(addrbuf));
 +  tor_assert(dest_addr_len > 0);
 +
 +  log_debug(LD_NET, "Connecting to %s:%u.",
 +            escaped_safe_str_client(address), port);
 +
 +  return connection_connect_sockaddr(conn, dest_addr, dest_addr_len,
 +                                     bind_addr, bind_addr_len, socket_error);
 +}
 +
 +#ifdef HAVE_SYS_UN_H
 +
 +/** Take conn, make a nonblocking socket; try to connect to
 + * an AF_UNIX socket at socket_path. If fail, return -1 and if applicable
 + * put your best guess about errno into *<b>socket_error</b>. Else assign s
 + * to conn-\>s: if connected return 1, if EAGAIN return 0.
 + *
 + * On success, add conn to the list of polled connections.
 + */
 +int
 +connection_connect_unix(connection_t *conn, const char *socket_path,
 +                        int *socket_error)
 +{
 +  struct sockaddr_un dest_addr;
 +
 +  tor_assert(socket_path);
 +
 +  /* Check that we'll be able to fit it into dest_addr later */
 +  if (strlen(socket_path) + 1 > sizeof(dest_addr.sun_path)) {
 +    log_warn(LD_NET,
 +             "Path %s is too long for an AF_UNIX socket\n",
 +             escaped_safe_str_client(socket_path));
 +    *socket_error = SOCK_ERRNO(ENAMETOOLONG);
 +    return -1;
 +  }
 +
 +  memset(&dest_addr, 0, sizeof(dest_addr));
 +  dest_addr.sun_family = AF_UNIX;
 +  strlcpy(dest_addr.sun_path, socket_path, sizeof(dest_addr.sun_path));
 +
 +  log_debug(LD_NET,
 +            "Connecting to AF_UNIX socket at %s.",
 +            escaped_safe_str_client(socket_path));
 +
 +  return connection_connect_sockaddr(conn,
 +                       (struct sockaddr *)&dest_addr, sizeof(dest_addr),
 +                       NULL, 0, socket_error);
 +}
 +
 +#endif /* defined(HAVE_SYS_UN_H) */
 +
 +/** Convert state number to string representation for logging purposes.
 + */
 +static const char *
 +connection_proxy_state_to_string(int state)
 +{
 +  static const char *unknown = "???";
 +  static const char *states[] = {
 +    "PROXY_NONE",
 +    "PROXY_INFANT",
 +    "PROXY_HTTPS_WANT_CONNECT_OK",
 +    "PROXY_SOCKS4_WANT_CONNECT_OK",
 +    "PROXY_SOCKS5_WANT_AUTH_METHOD_NONE",
 +    "PROXY_SOCKS5_WANT_AUTH_METHOD_RFC1929",
 +    "PROXY_SOCKS5_WANT_AUTH_RFC1929_OK",
 +    "PROXY_SOCKS5_WANT_CONNECT_OK",
 +    "PROXY_CONNECTED",
 +  };
 +
 +  if (state < PROXY_NONE || state > PROXY_CONNECTED)
 +    return unknown;
 +
 +  return states[state];
 +}
 +
 +/** Returns the global proxy type used by tor. Use this function for
 + *  logging or high-level purposes, don't use it to fill the
 + *  <b>proxy_type</b> field of or_connection_t; use the actual proxy
 + *  protocol instead.*/
 +static int
 +get_proxy_type(void)
 +{
 +  const or_options_t *options = get_options();
 +
 +  if (options->ClientTransportPlugin)
 +    return PROXY_PLUGGABLE;
 +  else if (options->HTTPSProxy)
 +    return PROXY_CONNECT;
 +  else if (options->Socks4Proxy)
 +    return PROXY_SOCKS4;
 +  else if (options->Socks5Proxy)
 +    return PROXY_SOCKS5;
 +  else
 +    return PROXY_NONE;
 +}
 +
 +/* One byte for the version, one for the command, two for the
 +   port, and four for the addr... and, one more for the
 +   username NUL: */
 +#define SOCKS4_STANDARD_BUFFER_SIZE (1 + 1 + 2 + 4 + 1)
 +
 +/** Write a proxy request of <b>type</b> (socks4, socks5, https) to conn
 + * for conn->addr:conn->port, authenticating with the auth details given
 + * in the configuration (if available). SOCKS 5 and HTTP CONNECT proxies
 + * support authentication.
 + *
 + * Returns -1 if conn->addr is incompatible with the proxy protocol, and
 + * 0 otherwise.
 + *
 + * Use connection_read_proxy_handshake() to complete the handshake.
 + */
 +int
 +connection_proxy_connect(connection_t *conn, int type)
 +{
 +  const or_options_t *options;
 +
 +  tor_assert(conn);
 +
 +  options = get_options();
 +
 +  switch (type) {
 +    case PROXY_CONNECT: {
 +      char buf[1024];
 +      char *base64_authenticator=NULL;
 +      const char *authenticator = options->HTTPSProxyAuthenticator;
 +
 +      /* Send HTTP CONNECT and authentication (if available) in
 +       * one request */
 +
 +      if (authenticator) {
 +        base64_authenticator = alloc_http_authenticator(authenticator);
 +        if (!base64_authenticator)
 +          log_warn(LD_OR, "Encoding https authenticator failed");
 +      }
 +
 +      if (base64_authenticator) {
 +        const char *addrport = fmt_addrport(&conn->addr, conn->port);
 +        tor_snprintf(buf, sizeof(buf), "CONNECT %s HTTP/1.1\r\n"
 +                     "Host: %s\r\n"
 +                     "Proxy-Authorization: Basic %s\r\n\r\n",
 +                     addrport,
 +                     addrport,
 +                     base64_authenticator);
 +        tor_free(base64_authenticator);
 +      } else {
 +        tor_snprintf(buf, sizeof(buf), "CONNECT %s HTTP/1.0\r\n\r\n",
 +                     fmt_addrport(&conn->addr, conn->port));
 +      }
 +
 +      connection_buf_add(buf, strlen(buf), conn);
 +      conn->proxy_state = PROXY_HTTPS_WANT_CONNECT_OK;
 +      break;
 +    }
 +
 +    case PROXY_SOCKS4: {
 +      unsigned char *buf;
 +      uint16_t portn;
 +      uint32_t ip4addr;
 +      size_t buf_size = 0;
 +      char *socks_args_string = NULL;
 +
 +      /* Send a SOCKS4 connect request */
 +
 +      if (tor_addr_family(&conn->addr) != AF_INET) {
 +        log_warn(LD_NET, "SOCKS4 client is incompatible with IPv6");
 +        return -1;
 +      }
 +
 +      { /* If we are here because we are trying to connect to a
 +           pluggable transport proxy, check if we have any SOCKS
 +           arguments to transmit. If we do, compress all arguments to
 +           a single string in 'socks_args_string': */
 +
 +        if (get_proxy_type() == PROXY_PLUGGABLE) {
 +          socks_args_string =
 +            pt_get_socks_args_for_proxy_addrport(&conn->addr, conn->port);
 +          if (socks_args_string)
 +            log_debug(LD_NET, "Sending out '%s' as our SOCKS argument string.",
 +                      socks_args_string);
 +        }
 +      }
 +
 +      { /* Figure out the buffer size we need for the SOCKS message: */
 +
 +        buf_size = SOCKS4_STANDARD_BUFFER_SIZE;
 +
 +        /* If we have a SOCKS argument string, consider its size when
 +           calculating the buffer size: */
 +        if (socks_args_string)
 +          buf_size += strlen(socks_args_string);
 +      }
 +
 +      buf = tor_malloc_zero(buf_size);
 +
 +      ip4addr = tor_addr_to_ipv4n(&conn->addr);
 +      portn = htons(conn->port);
 +
 +      buf[0] = 4; /* version */
 +      buf[1] = SOCKS_COMMAND_CONNECT; /* command */
 +      memcpy(buf + 2, &portn, 2); /* port */
 +      memcpy(buf + 4, &ip4addr, 4); /* addr */
 +
 +      /* Next packet field is the userid. If we have pluggable
 +         transport SOCKS arguments, we have to embed them
 +         there. Otherwise, we use an empty userid.  */
 +      if (socks_args_string) { /* place the SOCKS args string: */
 +        tor_assert(strlen(socks_args_string) > 0);
 +        tor_assert(buf_size >=
 +                   SOCKS4_STANDARD_BUFFER_SIZE + strlen(socks_args_string));
 +        strlcpy((char *)buf + 8, socks_args_string, buf_size - 8);
 +        tor_free(socks_args_string);
 +      } else {
 +        buf[8] = 0; /* no userid */
 +      }
 +
 +      connection_buf_add((char *)buf, buf_size, conn);
 +      tor_free(buf);
 +
 +      conn->proxy_state = PROXY_SOCKS4_WANT_CONNECT_OK;
 +      break;
 +    }
 +
 +    case PROXY_SOCKS5: {
 +      unsigned char buf[4]; /* fields: vers, num methods, method list */
 +
 +      /* Send a SOCKS5 greeting (connect request must wait) */
 +
 +      buf[0] = 5; /* version */
 +
 +      /* We have to use SOCKS5 authentication, if we have a
 +         Socks5ProxyUsername or if we want to pass arguments to our
 +         pluggable transport proxy: */
 +      if ((options->Socks5ProxyUsername) ||
 +          (get_proxy_type() == PROXY_PLUGGABLE &&
 +           (get_socks_args_by_bridge_addrport(&conn->addr, conn->port)))) {
 +      /* number of auth methods */
 +        buf[1] = 2;
 +        buf[2] = 0x00; /* no authentication */
 +        buf[3] = 0x02; /* rfc1929 Username/Passwd auth */
 +        conn->proxy_state = PROXY_SOCKS5_WANT_AUTH_METHOD_RFC1929;
 +      } else {
 +        buf[1] = 1;
 +        buf[2] = 0x00; /* no authentication */
 +        conn->proxy_state = PROXY_SOCKS5_WANT_AUTH_METHOD_NONE;
 +      }
 +
 +      connection_buf_add((char *)buf, 2 + buf[1], conn);
 +      break;
 +    }
 +
 +    default:
 +      log_err(LD_BUG, "Invalid proxy protocol, %d", type);
 +      tor_fragile_assert();
 +      return -1;
 +  }
 +
 +  log_debug(LD_NET, "set state %s",
 +            connection_proxy_state_to_string(conn->proxy_state));
 +
 +  return 0;
 +}
 +
 +/** Read conn's inbuf. If the http response from the proxy is all
 + * here, make sure it's good news, then return 1. If it's bad news,
 + * return -1. Else return 0 and hope for better luck next time.
 + */
 +static int
 +connection_read_https_proxy_response(connection_t *conn)
 +{
 +  char *headers;
 +  char *reason=NULL;
 +  int status_code;
 +  time_t date_header;
 +
 +  switch (fetch_from_buf_http(conn->inbuf,
 +                              &headers, MAX_HEADERS_SIZE,
 +                              NULL, NULL, 10000, 0)) {
 +    case -1: /* overflow */
 +      log_warn(LD_PROTOCOL,
 +               "Your https proxy sent back an oversized response. Closing.");
 +      return -1;
 +    case 0:
 +      log_info(LD_NET,"https proxy response not all here yet. Waiting.");
 +      return 0;
 +    /* case 1, fall through */
 +  }
 +
 +  if (parse_http_response(headers, &status_code, &date_header,
 +                          NULL, &reason) < 0) {
 +    log_warn(LD_NET,
 +             "Unparseable headers from proxy (connecting to '%s'). Closing.",
 +             conn->address);
 +    tor_free(headers);
 +    return -1;
 +  }
 +  tor_free(headers);
 +  if (!reason) reason = tor_strdup("[no reason given]");
 +
 +  if (status_code == 200) {
 +    log_info(LD_NET,
 +             "HTTPS connect to '%s' successful! (200 %s) Starting TLS.",
 +             conn->address, escaped(reason));
 +    tor_free(reason);
 +    return 1;
 +  }
 +  /* else, bad news on the status code */
 +  switch (status_code) {
 +    case 403:
 +      log_warn(LD_NET,
 +             "The https proxy refused to allow connection to %s "
 +             "(status code %d, %s). Closing.",
 +             conn->address, status_code, escaped(reason));
 +      break;
 +    default:
 +      log_warn(LD_NET,
 +             "The https proxy sent back an unexpected status code %d (%s). "
 +             "Closing.",
 +             status_code, escaped(reason));
 +      break;
 +  }
 +  tor_free(reason);
 +  return -1;
 +}
 +
 +/** Send SOCKS5 CONNECT command to <b>conn</b>, copying <b>conn->addr</b>
 + * and <b>conn->port</b> into the request.
 + */
 +static void
 +connection_send_socks5_connect(connection_t *conn)
 +{
 +  unsigned char buf[1024];
 +  size_t reqsize = 6;
 +  uint16_t port = htons(conn->port);
 +
 +  buf[0] = 5; /* version */
 +  buf[1] = SOCKS_COMMAND_CONNECT; /* command */
 +  buf[2] = 0; /* reserved */
 +
 +  if (tor_addr_family(&conn->addr) == AF_INET) {
 +    uint32_t addr = tor_addr_to_ipv4n(&conn->addr);
 +
 +    buf[3] = 1;
 +    reqsize += 4;
 +    memcpy(buf + 4, &addr, 4);
 +    memcpy(buf + 8, &port, 2);
 +  } else { /* AF_INET6 */
 +    buf[3] = 4;
 +    reqsize += 16;
 +    memcpy(buf + 4, tor_addr_to_in6_addr8(&conn->addr), 16);
 +    memcpy(buf + 20, &port, 2);
 +  }
 +
 +  connection_buf_add((char *)buf, reqsize, conn);
 +
 +  conn->proxy_state = PROXY_SOCKS5_WANT_CONNECT_OK;
 +}
 +
 +/** Wrapper around fetch_from_buf_socks_client: see that functions
 + * for documentation of its behavior. */
 +static int
 +connection_fetch_from_buf_socks_client(connection_t *conn,
 +                                       int state, char **reason)
 +{
 +  return fetch_from_buf_socks_client(conn->inbuf, state, reason);
 +}
 +
 +/** Call this from connection_*_process_inbuf() to advance the proxy
 + * handshake.
 + *
 + * No matter what proxy protocol is used, if this function returns 1, the
 + * handshake is complete, and the data remaining on inbuf may contain the
 + * start of the communication with the requested server.
 + *
 + * Returns 0 if the current buffer contains an incomplete response, and -1
 + * on error.
 + */
 +int
 +connection_read_proxy_handshake(connection_t *conn)
 +{
 +  int ret = 0;
 +  char *reason = NULL;
 +
 +  log_debug(LD_NET, "enter state %s",
 +            connection_proxy_state_to_string(conn->proxy_state));
 +
 +  switch (conn->proxy_state) {
 +    case PROXY_HTTPS_WANT_CONNECT_OK:
 +      ret = connection_read_https_proxy_response(conn);
 +      if (ret == 1)
 +        conn->proxy_state = PROXY_CONNECTED;
 +      break;
 +
 +    case PROXY_SOCKS4_WANT_CONNECT_OK:
 +      ret = connection_fetch_from_buf_socks_client(conn,
 +                                                   conn->proxy_state,
 +                                                   &reason);
 +      if (ret == 1)
 +        conn->proxy_state = PROXY_CONNECTED;
 +      break;
 +
 +    case PROXY_SOCKS5_WANT_AUTH_METHOD_NONE:
 +      ret = connection_fetch_from_buf_socks_client(conn,
 +                                                   conn->proxy_state,
 +                                                   &reason);
 +      /* no auth needed, do connect */
 +      if (ret == 1) {
 +        connection_send_socks5_connect(conn);
 +        ret = 0;
 +      }
 +      break;
 +
 +    case PROXY_SOCKS5_WANT_AUTH_METHOD_RFC1929:
 +      ret = connection_fetch_from_buf_socks_client(conn,
 +                                                   conn->proxy_state,
 +                                                   &reason);
 +
 +      /* send auth if needed, otherwise do connect */
 +      if (ret == 1) {
 +        connection_send_socks5_connect(conn);
 +        ret = 0;
 +      } else if (ret == 2) {
 +        unsigned char buf[1024];
 +        size_t reqsize, usize, psize;
 +        const char *user, *pass;
 +        char *socks_args_string = NULL;
 +
 +        if (get_proxy_type() == PROXY_PLUGGABLE) {
 +          socks_args_string =
 +            pt_get_socks_args_for_proxy_addrport(&conn->addr, conn->port);
 +          if (!socks_args_string) {
 +            log_warn(LD_NET, "Could not create SOCKS args string.");
 +            ret = -1;
 +            break;
 +          }
 +
 +          log_debug(LD_NET, "SOCKS5 arguments: %s", socks_args_string);
 +          tor_assert(strlen(socks_args_string) > 0);
 +          tor_assert(strlen(socks_args_string) <= MAX_SOCKS5_AUTH_SIZE_TOTAL);
 +
 +          if (strlen(socks_args_string) > MAX_SOCKS5_AUTH_FIELD_SIZE) {
 +            user = socks_args_string;
 +            usize = MAX_SOCKS5_AUTH_FIELD_SIZE;
 +            pass = socks_args_string + MAX_SOCKS5_AUTH_FIELD_SIZE;
 +            psize = strlen(socks_args_string) - MAX_SOCKS5_AUTH_FIELD_SIZE;
 +          } else {
 +            user = socks_args_string;
 +            usize = strlen(socks_args_string);
 +            pass = "\0";
 +            psize = 1;
 +          }
 +        } else if (get_options()->Socks5ProxyUsername) {
 +          user = get_options()->Socks5ProxyUsername;
 +          pass = get_options()->Socks5ProxyPassword;
 +          tor_assert(user && pass);
 +          usize = strlen(user);
 +          psize = strlen(pass);
 +        } else {
 +          log_err(LD_BUG, "We entered %s for no reason!", __func__);
 +          tor_fragile_assert();
 +          ret = -1;
 +          break;
 +        }
 +
 +        /* Username and password lengths should have been checked
 +           above and during torrc parsing. */
 +        tor_assert(usize <= MAX_SOCKS5_AUTH_FIELD_SIZE &&
 +                   psize <= MAX_SOCKS5_AUTH_FIELD_SIZE);
 +        reqsize = 3 + usize + psize;
 +
 +        buf[0] = 1; /* negotiation version */
 +        buf[1] = usize;
 +        memcpy(buf + 2, user, usize);
 +        buf[2 + usize] = psize;
 +        memcpy(buf + 3 + usize, pass, psize);
 +
 +        if (socks_args_string)
 +          tor_free(socks_args_string);
 +
 +        connection_buf_add((char *)buf, reqsize, conn);
 +
 +        conn->proxy_state = PROXY_SOCKS5_WANT_AUTH_RFC1929_OK;
 +        ret = 0;
 +      }
 +      break;
 +
 +    case PROXY_SOCKS5_WANT_AUTH_RFC1929_OK:
 +      ret = connection_fetch_from_buf_socks_client(conn,
 +                                                   conn->proxy_state,
 +                                                   &reason);
 +      /* send the connect request */
 +      if (ret == 1) {
 +        connection_send_socks5_connect(conn);
 +        ret = 0;
 +      }
 +      break;
 +
 +    case PROXY_SOCKS5_WANT_CONNECT_OK:
 +      ret = connection_fetch_from_buf_socks_client(conn,
 +                                                   conn->proxy_state,
 +                                                   &reason);
 +      if (ret == 1)
 +        conn->proxy_state = PROXY_CONNECTED;
 +      break;
 +
 +    default:
 +      log_err(LD_BUG, "Invalid proxy_state for reading, %d",
 +              conn->proxy_state);
 +      tor_fragile_assert();
 +      ret = -1;
 +      break;
 +  }
 +
 +  log_debug(LD_NET, "leaving state %s",
 +            connection_proxy_state_to_string(conn->proxy_state));
 +
 +  if (ret < 0) {
 +    if (reason) {
 +      log_warn(LD_NET, "Proxy Client: unable to connect to %s:%d (%s)",
 +                conn->address, conn->port, escaped(reason));
 +      tor_free(reason);
 +    } else {
 +      log_warn(LD_NET, "Proxy Client: unable to connect to %s:%d",
 +                conn->address, conn->port);
 +    }
 +  } else if (ret == 1) {
 +    log_info(LD_NET, "Proxy Client: connection to %s:%d successful",
 +              conn->address, conn->port);
 +  }
 +
 +  return ret;
 +}
 +
 +/** Given a list of listener connections in <b>old_conns</b>, and list of
 + * port_cfg_t entries in <b>ports</b>, open a new listener for every port in
 + * <b>ports</b> that does not already have a listener in <b>old_conns</b>.
 + *
 + * Remove from <b>old_conns</b> every connection that has a corresponding
 + * entry in <b>ports</b>.  Add to <b>new_conns</b> new every connection we
 + * launch. If we may need to perform socket rebind when creating new
 + * listener that replaces old one, create a <b>listener_replacement_t</b>
 + * struct for affected pair  and add it to <b>replacements</b>.
 + *
 + * If <b>control_listeners_only</b> is true, then we only open control
 + * listeners, and we do not remove any noncontrol listeners from
 + * old_conns.
 + *
 + * Return 0 on success, -1 on failure.
 + **/
 +static int
 +retry_listener_ports(smartlist_t *old_conns,
 +                     const smartlist_t *ports,
 +                     smartlist_t *new_conns,
 +                     smartlist_t *replacements,
 +                     int control_listeners_only)
 +{
 +#ifndef ENABLE_LISTENER_REBIND
 +  (void)replacements;
 +#endif
 +
 +  smartlist_t *launch = smartlist_new();
 +  int r = 0;
 +
 +  if (control_listeners_only) {
 +    SMARTLIST_FOREACH(ports, port_cfg_t *, p, {
 +        if (p->type == CONN_TYPE_CONTROL_LISTENER)
 +          smartlist_add(launch, p);
 +    });
 +  } else {
 +    smartlist_add_all(launch, ports);
 +  }
 +
 +  /* Iterate through old_conns, comparing it to launch: remove from both lists
 +   * each pair of elements that corresponds to the same port. */
 +  SMARTLIST_FOREACH_BEGIN(old_conns, connection_t *, conn) {
 +    const port_cfg_t *found_port = NULL;
 +
 +    /* Okay, so this is a listener.  Is it configured? */
 +    /* That is, is it either: 1) exact match - address and port
 +     * pair match exactly between old listener and new port; or 2)
 +     * wildcard match - port matches exactly, but *one* of the
 +     * addresses is wildcard (0.0.0.0 or ::)?
 +     */
 +    SMARTLIST_FOREACH_BEGIN(launch, const port_cfg_t *, wanted) {
 +      if (conn->type != wanted->type)
 +        continue;
 +      if ((conn->socket_family != AF_UNIX && wanted->is_unix_addr) ||
 +          (conn->socket_family == AF_UNIX && ! wanted->is_unix_addr))
 +        continue;
 +
 +      if (wanted->server_cfg.no_listen)
 +        continue; /* We don't want to open a listener for this one */
 +
 +      if (wanted->is_unix_addr) {
 +        if (conn->socket_family == AF_UNIX &&
 +            !strcmp(wanted->unix_addr, conn->address)) {
 +          found_port = wanted;
 +          break;
 +        }
 +      } else {
 +        /* Numeric values of old and new port match exactly. */
 +        const int port_matches_exact = (wanted->port == conn->port);
 +        /* Ports match semantically - either their specific values
 +           match exactly, or new port is 'auto'.
 +         */
 +        const int port_matches = (wanted->port == CFG_AUTO_PORT ||
 +                                  port_matches_exact);
 +
 +        if (port_matches && tor_addr_eq(&wanted->addr, &conn->addr)) {
 +          found_port = wanted;
 +          break;
 +        }
 +#ifdef ENABLE_LISTENER_REBIND
 +        /* Rebinding may be needed if all of the following are true:
 +         * 1) Address family is the same in old and new listeners.
 +         * 2) Port number matches exactly (numeric value is the same).
 +         * 3) *One* of listeners (either old one or new one) has a
 +         *    wildcard IP address (0.0.0.0 or [::]).
 +         *
 +         * These are the exact conditions for a first bind() syscall
 +         * to fail with EADDRINUSE.
 +         */
 +        const int may_need_rebind =
 +          tor_addr_family(&wanted->addr) == tor_addr_family(&conn->addr) &&
 +          port_matches_exact && bool_neq(tor_addr_is_null(&wanted->addr),
 +                                         tor_addr_is_null(&conn->addr));
 +        if (replacements && may_need_rebind) {
 +          listener_replacement_t *replacement =
 +            tor_malloc(sizeof(listener_replacement_t));
 +
 +          replacement->old_conn = conn;
 +          replacement->new_port = wanted;
 +          smartlist_add(replacements, replacement);
 +
 +          SMARTLIST_DEL_CURRENT(launch, wanted);
 +          SMARTLIST_DEL_CURRENT(old_conns, conn);
 +          break;
 +        }
 +#endif
 +      }
 +    } SMARTLIST_FOREACH_END(wanted);
 +
 +    if (found_port) {
 +      /* This listener is already running; we don't need to launch it. */
 +      //log_debug(LD_NET, "Already have %s on %s:%d",
 +      //    conn_type_to_string(found_port->type), conn->address, conn->port);
 +      smartlist_remove(launch, found_port);
 +      /* And we can remove the connection from old_conns too. */
 +      SMARTLIST_DEL_CURRENT(old_conns, conn);
 +    }
 +  } SMARTLIST_FOREACH_END(conn);
 +
 +  /* Now open all the listeners that are configured but not opened. */
 +  SMARTLIST_FOREACH_BEGIN(launch, const port_cfg_t *, port) {
 +    int skip = 0;
 +    connection_t *conn = connection_listener_new_for_port(port, &skip, NULL);
 +
 +    if (conn && new_conns)
 +      smartlist_add(new_conns, conn);
 +    else if (!skip)
 +      r = -1;
 +  } SMARTLIST_FOREACH_END(port);
 +
 +  smartlist_free(launch);
 +
 +  return r;
 +}
 +
 +/** Launch listeners for each port you should have open.  Only launch
 + * listeners who are not already open, and only close listeners we no longer
 + * want.
 + *
 + * Add all new connections to <b>new_conns</b>.
 + *
 + * If <b>close_all_noncontrol</b> is true, then we only open control
 + * listeners, and we close all other listeners.
 + */
 +int
 +retry_all_listeners(smartlist_t *new_conns, int close_all_noncontrol)
 +{
 +  smartlist_t *listeners = smartlist_new();
 +  smartlist_t *replacements = smartlist_new();
 +  const or_options_t *options = get_options();
 +  int retval = 0;
 +  const uint16_t old_or_port = router_get_advertised_or_port(options);
 +  const uint16_t old_or_port_ipv6 =
 +    router_get_advertised_or_port_by_af(options,AF_INET6);
 +  const uint16_t old_dir_port = router_get_advertised_dir_port(options, 0);
 +
 +  SMARTLIST_FOREACH_BEGIN(get_connection_array(), connection_t *, conn) {
 +    if (connection_is_listener(conn) && !conn->marked_for_close)
 +      smartlist_add(listeners, conn);
 +  } SMARTLIST_FOREACH_END(conn);
 +
 +  if (retry_listener_ports(listeners,
 +                           get_configured_ports(),
 +                           new_conns,
 +                           replacements,
 +                           close_all_noncontrol) < 0)
 +    retval = -1;
 +
 +#ifdef ENABLE_LISTENER_REBIND
 +  SMARTLIST_FOREACH_BEGIN(replacements, listener_replacement_t *, r) {
 +    int addr_in_use = 0;
 +    int skip = 0;
 +
 +    tor_assert(r->new_port);
 +    tor_assert(r->old_conn);
 +
 +    connection_t *new_conn =
 +      connection_listener_new_for_port(r->new_port, &skip, &addr_in_use);
 +    connection_t *old_conn = r->old_conn;
 +
 +    if (skip)
 +      continue;
 +
 +    connection_close_immediate(old_conn);
 +    connection_mark_for_close(old_conn);
 +
 +    if (addr_in_use) {
 +      new_conn = connection_listener_new_for_port(r->new_port,
 +                                                  &skip, &addr_in_use);
 +    }
 +
 +    tor_assert(new_conn);
 +
 +    smartlist_add(new_conns, new_conn);
 +
 +    log_notice(LD_NET, "Closed no-longer-configured %s on %s:%d "
 +                       "(replaced by %s:%d)",
 +               conn_type_to_string(old_conn->type), old_conn->address,
 +               old_conn->port, new_conn->address, new_conn->port);
 +  } SMARTLIST_FOREACH_END(r);
 +#endif
 +
 +  /* Any members that were still in 'listeners' don't correspond to
 +   * any configured port.  Kill 'em. */
 +  SMARTLIST_FOREACH_BEGIN(listeners, connection_t *, conn) {
 +    log_notice(LD_NET, "Closing no-longer-configured %s on %s:%d",
 +               conn_type_to_string(conn->type), conn->address, conn->port);
 +    connection_close_immediate(conn);
 +    connection_mark_for_close(conn);
 +  } SMARTLIST_FOREACH_END(conn);
 +
 +  smartlist_free(listeners);
 +  /* Cleanup any remaining listener replacement. */
 +  SMARTLIST_FOREACH(replacements, listener_replacement_t *, r, tor_free(r));
 +  smartlist_free(replacements);
 +
 +  if (old_or_port != router_get_advertised_or_port(options) ||
 +      old_or_port_ipv6 != router_get_advertised_or_port_by_af(options,
 +                                                              AF_INET6) ||
 +      old_dir_port != router_get_advertised_dir_port(options, 0)) {
 +    /* Our chosen ORPort or DirPort is not what it used to be: the
 +     * descriptor we had (if any) should be regenerated.  (We won't
 +     * automatically notice this because of changes in the option,
 +     * since the value could be "auto".) */
 +    mark_my_descriptor_dirty("Chosen Or/DirPort changed");
 +  }
 +
 +  return retval;
 +}
 +
 +/** Mark every listener of type other than CONTROL_LISTENER to be closed. */
 +void
 +connection_mark_all_noncontrol_listeners(void)
 +{
 +  SMARTLIST_FOREACH_BEGIN(get_connection_array(), connection_t *, conn) {
 +    if (conn->marked_for_close)
 +      continue;
 +    if (conn->type == CONN_TYPE_CONTROL_LISTENER)
 +      continue;
 +    if (connection_is_listener(conn))
 +      connection_mark_for_close(conn);
 +  } SMARTLIST_FOREACH_END(conn);
 +}
 +
 +/** Mark every external connection not used for controllers for close. */
 +void
 +connection_mark_all_noncontrol_connections(void)
 +{
 +  SMARTLIST_FOREACH_BEGIN(get_connection_array(), connection_t *, conn) {
 +    if (conn->marked_for_close)
 +      continue;
 +    switch (conn->type) {
 +      case CONN_TYPE_CONTROL_LISTENER:
 +      case CONN_TYPE_CONTROL:
 +        break;
 +      case CONN_TYPE_AP:
 +        connection_mark_unattached_ap(TO_ENTRY_CONN(conn),
 +                                      END_STREAM_REASON_HIBERNATING);
 +        break;
 +      case CONN_TYPE_OR:
 +        {
 +          or_connection_t *orconn = TO_OR_CONN(conn);
 +          if (orconn->chan) {
 +            connection_or_close_normally(orconn, 0);
 +          } else {
 +            /*
 +             * There should have been one, but mark for close and hope
 +             * for the best..
 +             */
 +            connection_mark_for_close(conn);
 +          }
 +        }
 +        break;
 +      default:
 +        connection_mark_for_close(conn);
 +        break;
 +    }
 +  } SMARTLIST_FOREACH_END(conn);
 +}
 +
 +/** Return 1 if we should apply rate limiting to <b>conn</b>, and 0
 + * otherwise.
 + * Right now this just checks if it's an internal IP address or an
 + * internal connection. We also should, but don't, check if the connection
 + * uses pluggable transports, since we should then limit it even if it
 + * comes from an internal IP address. */
 +static int
 +connection_is_rate_limited(connection_t *conn)
 +{
 +  const or_options_t *options = get_options();
 +  if (conn->linked)
 +    return 0; /* Internal connection */
 +  else if (! options->CountPrivateBandwidth &&
 +           (tor_addr_family(&conn->addr) == AF_UNSPEC || /* no address */
 +            tor_addr_family(&conn->addr) == AF_UNIX ||   /* no address */
 +            tor_addr_is_internal(&conn->addr, 0)))
 +    return 0; /* Internal address */
 +  else
 +    return 1;
 +}
 +
 +/** When was either global write bucket last empty? If this was recent, then
 + * we're probably low on bandwidth, and we should be stingy with our bandwidth
 + * usage. */
 +static time_t write_buckets_last_empty_at = -100;
 +
 +/** How many seconds of no active local circuits will make the
 + * connection revert to the "relayed" bandwidth class? */
 +#define CLIENT_IDLE_TIME_FOR_PRIORITY 30
 +
 +/** Return 1 if <b>conn</b> should use tokens from the "relayed"
 + * bandwidth rates, else 0. Currently, only OR conns with bandwidth
 + * class 1, and directory conns that are serving data out, count.
 + */
 +static int
 +connection_counts_as_relayed_traffic(connection_t *conn, time_t now)
 +{
 +  if (conn->type == CONN_TYPE_OR &&
 +      connection_or_client_used(TO_OR_CONN(conn)) +
 +                                CLIENT_IDLE_TIME_FOR_PRIORITY < now)
 +    return 1;
 +  if (conn->type == CONN_TYPE_DIR && DIR_CONN_IS_SERVER(conn))
 +    return 1;
 +  return 0;
 +}
 +
 +/** Helper function to decide how many bytes out of <b>global_bucket</b>
 + * we're willing to use for this transaction. <b>base</b> is the size
 + * of a cell on the network; <b>priority</b> says whether we should
 + * write many of them or just a few; and <b>conn_bucket</b> (if
 + * non-negative) provides an upper limit for our answer. */
 +static ssize_t
 +connection_bucket_get_share(int base, int priority,
 +                            ssize_t global_bucket_val, ssize_t conn_bucket)
 +{
 +  ssize_t at_most;
 +  ssize_t num_bytes_high = (priority ? 32 : 16) * base;
 +  ssize_t num_bytes_low = (priority ? 4 : 2) * base;
 +
 +  /* Do a rudimentary limiting so one circuit can't hog a connection.
 +   * Pick at most 32 cells, at least 4 cells if possible, and if we're in
 +   * the middle pick 1/8 of the available bandwidth. */
 +  at_most = global_bucket_val / 8;
 +  at_most -= (at_most % base); /* round down */
 +  if (at_most > num_bytes_high) /* 16 KB, or 8 KB for low-priority */
 +    at_most = num_bytes_high;
 +  else if (at_most < num_bytes_low) /* 2 KB, or 1 KB for low-priority */
 +    at_most = num_bytes_low;
 +
 +  if (at_most > global_bucket_val)
 +    at_most = global_bucket_val;
 +
 +  if (conn_bucket >= 0 && at_most > conn_bucket)
 +    at_most = conn_bucket;
 +
 +  if (at_most < 0)
 +    return 0;
 +  return at_most;
 +}
 +
 +/** How many bytes at most can we read onto this connection? */
 +static ssize_t
 +connection_bucket_read_limit(connection_t *conn, time_t now)
 +{
 +  int base = RELAY_PAYLOAD_SIZE;
 +  int priority = conn->type != CONN_TYPE_DIR;
 +  ssize_t conn_bucket = -1;
 +  size_t global_bucket_val = token_bucket_rw_get_read(&global_bucket);
 +
 +  if (connection_speaks_cells(conn)) {
 +    or_connection_t *or_conn = TO_OR_CONN(conn);
 +    if (conn->state == OR_CONN_STATE_OPEN)
 +      conn_bucket = token_bucket_rw_get_read(&or_conn->bucket);
 +    base = get_cell_network_size(or_conn->wide_circ_ids);
 +  }
 +
 +  if (!connection_is_rate_limited(conn)) {
 +    /* be willing to read on local conns even if our buckets are empty */
 +    return conn_bucket>=0 ? conn_bucket : 1<<14;
 +  }
 +
 +  if (connection_counts_as_relayed_traffic(conn, now)) {
 +    size_t relayed = token_bucket_rw_get_read(&global_relayed_bucket);
 +    global_bucket_val = MIN(global_bucket_val, relayed);
 +  }
 +
 +  return connection_bucket_get_share(base, priority,
 +                                     global_bucket_val, conn_bucket);
 +}
 +
 +/** How many bytes at most can we write onto this connection? */
 +ssize_t
 +connection_bucket_write_limit(connection_t *conn, time_t now)
 +{
 +  int base = RELAY_PAYLOAD_SIZE;
 +  int priority = conn->type != CONN_TYPE_DIR;
 +  size_t conn_bucket = conn->outbuf_flushlen;
 +  size_t global_bucket_val = token_bucket_rw_get_write(&global_bucket);
 +
 +  if (!connection_is_rate_limited(conn)) {
 +    /* be willing to write to local conns even if our buckets are empty */
 +    return conn->outbuf_flushlen;
 +  }
 +
 +  if (connection_speaks_cells(conn)) {
 +    /* use the per-conn write limit if it's lower */
 +    or_connection_t *or_conn = TO_OR_CONN(conn);
 +    if (conn->state == OR_CONN_STATE_OPEN)
 +      conn_bucket = MIN(conn_bucket,
 +                        token_bucket_rw_get_write(&or_conn->bucket));
 +    base = get_cell_network_size(or_conn->wide_circ_ids);
 +  }
 +
 +  if (connection_counts_as_relayed_traffic(conn, now)) {
 +    size_t relayed = token_bucket_rw_get_write(&global_relayed_bucket);
 +    global_bucket_val = MIN(global_bucket_val, relayed);
 +  }
 +
 +  return connection_bucket_get_share(base, priority,
 +                                     global_bucket_val, conn_bucket);
 +}
 +
 +/** Return 1 if the global write buckets are low enough that we
 + * shouldn't send <b>attempt</b> bytes of low-priority directory stuff
 + * out to <b>conn</b>. Else return 0.
 +
 + * Priority was 1 for v1 requests (directories and running-routers),
 + * and 2 for v2 requests and later (statuses and descriptors).
 + *
 + * There are a lot of parameters we could use here:
 + * - global_relayed_write_bucket. Low is bad.
 + * - global_write_bucket. Low is bad.
 + * - bandwidthrate. Low is bad.
 + * - bandwidthburst. Not a big factor?
 + * - attempt. High is bad.
 + * - total bytes queued on outbufs. High is bad. But I'm wary of
 + *   using this, since a few slow-flushing queues will pump up the
 + *   number without meaning what we meant to mean. What we really
 + *   mean is "total directory bytes added to outbufs recently", but
 + *   that's harder to quantify and harder to keep track of.
 + */
 +int
 +global_write_bucket_low(connection_t *conn, size_t attempt, int priority)
 +{
 +  size_t smaller_bucket =
 +    MIN(token_bucket_rw_get_write(&global_bucket),
 +        token_bucket_rw_get_write(&global_relayed_bucket));
 +  if (authdir_mode(get_options()) && priority>1)
 +    return 0; /* there's always room to answer v2 if we're an auth dir */
 +
 +  if (!connection_is_rate_limited(conn))
 +    return 0; /* local conns don't get limited */
 +
 +  if (smaller_bucket < attempt)
 +    return 1; /* not enough space no matter the priority */
 +
 +  {
 +    const time_t diff = approx_time() - write_buckets_last_empty_at;
 +    if (diff <= 1)
 +      return 1; /* we're already hitting our limits, no more please */
 +  }
 +
 +  if (priority == 1) { /* old-style v1 query */
 +    /* Could we handle *two* of these requests within the next two seconds? */
 +    const or_options_t *options = get_options();
 +    size_t can_write = (size_t) (smaller_bucket
 +      + 2*(options->RelayBandwidthRate ? options->RelayBandwidthRate :
 +           options->BandwidthRate));
 +    if (can_write < 2*attempt)
 +      return 1;
 +  } else { /* v2 query */
 +    /* no further constraints yet */
 +  }
 +  return 0;
 +}
 +
 +/** When did we last tell the accounting subsystem about transmitted
 + * bandwidth? */
 +static time_t last_recorded_accounting_at = 0;
 +
 +/** Helper: adjusts our bandwidth history and informs the controller as
 + * appropriate, given that we have just read <b>num_read</b> bytes and written
 + * <b>num_written</b> bytes on <b>conn</b>. */
 +static void
 +record_num_bytes_transferred_impl(connection_t *conn,
 +                             time_t now, size_t num_read, size_t num_written)
 +{
 +  /* Count bytes of answering direct and tunneled directory requests */
 +  if (conn->type == CONN_TYPE_DIR && conn->purpose == DIR_PURPOSE_SERVER) {
 +    if (num_read > 0)
 +      rep_hist_note_dir_bytes_read(num_read, now);
 +    if (num_written > 0)
 +      rep_hist_note_dir_bytes_written(num_written, now);
 +  }
 +
 +  if (!connection_is_rate_limited(conn))
 +    return; /* local IPs are free */
 +
 +  if (conn->type == CONN_TYPE_OR)
 +    rep_hist_note_or_conn_bytes(conn->global_identifier, num_read,
 +                                num_written, now);
 +
 +  if (num_read > 0) {
 +    rep_hist_note_bytes_read(num_read, now);
 +  }
 +  if (num_written > 0) {
 +    rep_hist_note_bytes_written(num_written, now);
 +  }
 +  if (conn->type == CONN_TYPE_EXIT)
 +    rep_hist_note_exit_bytes(conn->port, num_written, num_read);
 +
 +  /* Remember these bytes towards statistics. */
 +  stats_increment_bytes_read_and_written(num_read, num_written);
 +
 +  /* Remember these bytes towards accounting. */
 +  if (accounting_is_enabled(get_options())) {
 +    if (now > last_recorded_accounting_at && last_recorded_accounting_at) {
 +      accounting_add_bytes(num_read, num_written,
 +                           (int)(now - last_recorded_accounting_at));
 +    } else {
 +      accounting_add_bytes(num_read, num_written, 0);
 +    }
 +    last_recorded_accounting_at = now;
 +  }
 +}
 +
 +/** We just read <b>num_read</b> and wrote <b>num_written</b> bytes
 + * onto <b>conn</b>. Decrement buckets appropriately. */
 +static void
 +connection_buckets_decrement(connection_t *conn, time_t now,
 +                             size_t num_read, size_t num_written)
 +{
 +  if (num_written >= INT_MAX || num_read >= INT_MAX) {
 +    log_err(LD_BUG, "Value out of range. num_read=%lu, num_written=%lu, "
 +             "connection type=%s, state=%s",
 +             (unsigned long)num_read, (unsigned long)num_written,
 +             conn_type_to_string(conn->type),
 +             conn_state_to_string(conn->type, conn->state));
 +    tor_assert_nonfatal_unreached();
 +    if (num_written >= INT_MAX)
 +      num_written = 1;
 +    if (num_read >= INT_MAX)
 +      num_read = 1;
 +  }
 +
 +  record_num_bytes_transferred_impl(conn, now, num_read, num_written);
 +
 +  if (!connection_is_rate_limited(conn))
 +    return; /* local IPs are free */
 +
 +  unsigned flags = 0;
 +  if (connection_counts_as_relayed_traffic(conn, now)) {
 +    flags = token_bucket_rw_dec(&global_relayed_bucket, num_read, num_written);
 +  }
 +  flags |= token_bucket_rw_dec(&global_bucket, num_read, num_written);
 +
 +  if (flags & TB_WRITE) {
 +    write_buckets_last_empty_at = now;
 +  }
 +  if (connection_speaks_cells(conn) && conn->state == OR_CONN_STATE_OPEN) {
 +    or_connection_t *or_conn = TO_OR_CONN(conn);
 +    token_bucket_rw_dec(&or_conn->bucket, num_read, num_written);
 +  }
 +}
 +
 +/**
 + * Mark <b>conn</b> as needing to stop reading because bandwidth has been
 + * exhausted.  If <b>is_global_bw</b>, it is closing because global bandwidth
 + * limit has been exhausted.  Otherwise, it is closing because its own
 + * bandwidth limit has been exhausted.
 + */
 +void
 +connection_read_bw_exhausted(connection_t *conn, bool is_global_bw)
 +{
 +  (void)is_global_bw;
 +  conn->read_blocked_on_bw = 1;
 +  connection_stop_reading(conn);
 +  reenable_blocked_connection_schedule();
 +}
 +
 +/**
 + * Mark <b>conn</b> as needing to stop reading because write bandwidth has
 + * been exhausted.  If <b>is_global_bw</b>, it is closing because global
 + * bandwidth limit has been exhausted.  Otherwise, it is closing because its
 + * own bandwidth limit has been exhausted.
 +*/
 +void
 +connection_write_bw_exhausted(connection_t *conn, bool is_global_bw)
 +{
 +  (void)is_global_bw;
 +  conn->write_blocked_on_bw = 1;
 +  connection_stop_writing(conn);
 +  reenable_blocked_connection_schedule();
 +}
 +
 +/** If we have exhausted our global buckets, or the buckets for conn,
 + * stop reading. */
 +void
 +connection_consider_empty_read_buckets(connection_t *conn)
 +{
 +  const char *reason;
 +
 +  if (!connection_is_rate_limited(conn))
 +    return; /* Always okay. */
 +
 +  int is_global = 1;
 +
 +  if (token_bucket_rw_get_read(&global_bucket) <= 0) {
 +    reason = "global read bucket exhausted. Pausing.";
 +  } else if (connection_counts_as_relayed_traffic(conn, approx_time()) &&
 +             token_bucket_rw_get_read(&global_relayed_bucket) <= 0) {
 +    reason = "global relayed read bucket exhausted. Pausing.";
 +  } else if (connection_speaks_cells(conn) &&
 +             conn->state == OR_CONN_STATE_OPEN &&
 +             token_bucket_rw_get_read(&TO_OR_CONN(conn)->bucket) <= 0) {
 +    reason = "connection read bucket exhausted. Pausing.";
 +    is_global = false;
 +  } else
 +    return; /* all good, no need to stop it */
 +
 +  LOG_FN_CONN(conn, (LOG_DEBUG, LD_NET, "%s", reason));
 +  connection_read_bw_exhausted(conn, is_global);
 +}
 +
 +/** If we have exhausted our global buckets, or the buckets for conn,
 + * stop writing. */
 +void
 +connection_consider_empty_write_buckets(connection_t *conn)
 +{
 +  const char *reason;
 +
 +  if (!connection_is_rate_limited(conn))
 +    return; /* Always okay. */
 +
 +  bool is_global = true;
 +  if (token_bucket_rw_get_write(&global_bucket) <= 0) {
 +    reason = "global write bucket exhausted. Pausing.";
 +  } else if (connection_counts_as_relayed_traffic(conn, approx_time()) &&
 +             token_bucket_rw_get_write(&global_relayed_bucket) <= 0) {
 +    reason = "global relayed write bucket exhausted. Pausing.";
 +  } else if (connection_speaks_cells(conn) &&
 +             conn->state == OR_CONN_STATE_OPEN &&
 +             token_bucket_rw_get_write(&TO_OR_CONN(conn)->bucket) <= 0) {
 +    reason = "connection write bucket exhausted. Pausing.";
 +    is_global = false;
 +  } else
 +    return; /* all good, no need to stop it */
 +
 +  LOG_FN_CONN(conn, (LOG_DEBUG, LD_NET, "%s", reason));
 +  connection_write_bw_exhausted(conn, is_global);
 +}
 +
 +/** Initialize the global buckets to the values configured in the
 + * options */
 +void
 +connection_bucket_init(void)
 +{
 +  const or_options_t *options = get_options();
 +  const uint32_t now_ts = monotime_coarse_get_stamp();
 +  token_bucket_rw_init(&global_bucket,
 +                    (int32_t)options->BandwidthRate,
 +                    (int32_t)options->BandwidthBurst,
 +                    now_ts);
 +  if (options->RelayBandwidthRate) {
 +    token_bucket_rw_init(&global_relayed_bucket,
 +                      (int32_t)options->RelayBandwidthRate,
 +                      (int32_t)options->RelayBandwidthBurst,
 +                      now_ts);
 +  } else {
 +    token_bucket_rw_init(&global_relayed_bucket,
 +                      (int32_t)options->BandwidthRate,
 +                      (int32_t)options->BandwidthBurst,
 +                      now_ts);
 +  }
 +
 +  reenable_blocked_connection_init(options);
 +}
 +
 +/** Update the global connection bucket settings to a new value. */
 +void
 +connection_bucket_adjust(const or_options_t *options)
 +{
 +  token_bucket_rw_adjust(&global_bucket,
 +                      (int32_t)options->BandwidthRate,
 +                      (int32_t)options->BandwidthBurst);
 +  if (options->RelayBandwidthRate) {
 +    token_bucket_rw_adjust(&global_relayed_bucket,
 +                        (int32_t)options->RelayBandwidthRate,
 +                        (int32_t)options->RelayBandwidthBurst);
 +  } else {
 +    token_bucket_rw_adjust(&global_relayed_bucket,
 +                        (int32_t)options->BandwidthRate,
 +                        (int32_t)options->BandwidthBurst);
 +  }
 +}
 +
 +/**
 + * Cached value of the last coarse-timestamp when we refilled the
 + * global buckets.
 + */
 +static uint32_t last_refilled_global_buckets_ts=0;
 +/**
 + * Refill the token buckets for a single connection <b>conn</b>, and the
 + * global token buckets as appropriate.  Requires that <b>now_ts</b> is
 + * the time in coarse timestamp units.
 + */
 +static void
 +connection_bucket_refill_single(connection_t *conn, uint32_t now_ts)
 +{
 +  /* Note that we only check for equality here: the underlying
 +   * token bucket functions can handle moving backwards in time if they
 +   * need to. */
 +  if (now_ts != last_refilled_global_buckets_ts) {
 +    token_bucket_rw_refill(&global_bucket, now_ts);
 +    token_bucket_rw_refill(&global_relayed_bucket, now_ts);
 +    last_refilled_global_buckets_ts = now_ts;
 +  }
 +
 +  if (connection_speaks_cells(conn) && conn->state == OR_CONN_STATE_OPEN) {
 +    or_connection_t *or_conn = TO_OR_CONN(conn);
 +    token_bucket_rw_refill(&or_conn->bucket, now_ts);
 +  }
 +}
 +
 +/**
 + * Event to re-enable all connections that were previously blocked on read or
 + * write.
 + */
 +static mainloop_event_t *reenable_blocked_connections_ev = NULL;
 +
 +/** True iff reenable_blocked_connections_ev is currently scheduled. */
 +static int reenable_blocked_connections_is_scheduled = 0;
 +
 +/** Delay after which to run reenable_blocked_connections_ev. */
 +static struct timeval reenable_blocked_connections_delay;
 +
 +/**
 + * Re-enable all connections that were previously blocked on read or write.
 + * This event is scheduled after enough time has elapsed to be sure
 + * that the buckets will refill when the connections have something to do.
 + */
 +static void
 +reenable_blocked_connections_cb(mainloop_event_t *ev, void *arg)
 +{
 +  (void)ev;
 +  (void)arg;
 +  SMARTLIST_FOREACH_BEGIN(get_connection_array(), connection_t *, conn) {
 +    if (conn->read_blocked_on_bw == 1) {
 +      connection_start_reading(conn);
 +      conn->read_blocked_on_bw = 0;
 +    }
 +    if (conn->write_blocked_on_bw == 1) {
 +      connection_start_writing(conn);
 +      conn->write_blocked_on_bw = 0;
 +    }
 +  } SMARTLIST_FOREACH_END(conn);
 +
 +  reenable_blocked_connections_is_scheduled = 0;
 +}
 +
 +/**
 + * Initialize the mainloop event that we use to wake up connections that
 + * find themselves blocked on bandwidth.
 + */
 +static void
 +reenable_blocked_connection_init(const or_options_t *options)
 +{
 +  if (! reenable_blocked_connections_ev) {
 +    reenable_blocked_connections_ev =
 +      mainloop_event_new(reenable_blocked_connections_cb, NULL);
 +    reenable_blocked_connections_is_scheduled = 0;
 +  }
 +  time_t sec = options->TokenBucketRefillInterval / 1000;
 +  int msec = (options->TokenBucketRefillInterval % 1000);
 +  reenable_blocked_connections_delay.tv_sec = sec;
 +  reenable_blocked_connections_delay.tv_usec = msec * 1000;
 +}
 +
 +/**
 + * Called when we have blocked a connection for being low on bandwidth:
 + * schedule an event to reenable such connections, if it is not already
 + * scheduled.
 + */
 +static void
 +reenable_blocked_connection_schedule(void)
 +{
 +  if (reenable_blocked_connections_is_scheduled)
 +    return;
 +  if (BUG(reenable_blocked_connections_ev == NULL)) {
 +    reenable_blocked_connection_init(get_options());
 +  }
 +  mainloop_event_schedule(reenable_blocked_connections_ev,
 +                          &reenable_blocked_connections_delay);
 +  reenable_blocked_connections_is_scheduled = 1;
 +}
 +
 +/** Read bytes from conn-\>s and process them.
 + *
 + * It calls connection_buf_read_from_socket() to bring in any new bytes,
 + * and then calls connection_process_inbuf() to process them.
 + *
 + * Mark the connection and return -1 if you want to close it, else
 + * return 0.
 + */
 +static int
 +connection_handle_read_impl(connection_t *conn)
 +{
 +  ssize_t max_to_read=-1, try_to_read;
 +  size_t before, n_read = 0;
 +  int socket_error = 0;
 +
 +  if (conn->marked_for_close)
 +    return 0; /* do nothing */
 +
 +  conn->timestamp_last_read_allowed = approx_time();
 +
 +  connection_bucket_refill_single(conn, monotime_coarse_get_stamp());
 +
 +  switch (conn->type) {
 +    case CONN_TYPE_OR_LISTENER:
 +      return connection_handle_listener_read(conn, CONN_TYPE_OR);
 +    case CONN_TYPE_EXT_OR_LISTENER:
 +      return connection_handle_listener_read(conn, CONN_TYPE_EXT_OR);
 +    case CONN_TYPE_AP_LISTENER:
 +    case CONN_TYPE_AP_TRANS_LISTENER:
 +    case CONN_TYPE_AP_NATD_LISTENER:
 +    case CONN_TYPE_AP_HTTP_CONNECT_LISTENER:
 +      return connection_handle_listener_read(conn, CONN_TYPE_AP);
 +    case CONN_TYPE_DIR_LISTENER:
 +      return connection_handle_listener_read(conn, CONN_TYPE_DIR);
 +    case CONN_TYPE_CONTROL_LISTENER:
 +      return connection_handle_listener_read(conn, CONN_TYPE_CONTROL);
 +    case CONN_TYPE_AP_DNS_LISTENER:
 +      /* This should never happen; eventdns.c handles the reads here. */
 +      tor_fragile_assert();
 +      return 0;
 +  }
 +
 + loop_again:
 +  try_to_read = max_to_read;
 +  tor_assert(!conn->marked_for_close);
 +
 +  before = buf_datalen(conn->inbuf);
 +  if (connection_buf_read_from_socket(conn, &max_to_read, &socket_error) < 0) {
 +    /* There's a read error; kill the connection.*/
 +    if (conn->type == CONN_TYPE_OR) {
 +      connection_or_notify_error(TO_OR_CONN(conn),
 +                                 socket_error != 0 ?
 +                                   errno_to_orconn_end_reason(socket_error) :
 +                                   END_OR_CONN_REASON_CONNRESET,
 +                                 socket_error != 0 ?
 +                                   tor_socket_strerror(socket_error) :
 +                                   "(unknown, errno was 0)");
 +    }
 +    if (CONN_IS_EDGE(conn)) {
 +      edge_connection_t *edge_conn = TO_EDGE_CONN(conn);
 +      connection_edge_end_errno(edge_conn);
 +      if (conn->type == CONN_TYPE_AP && TO_ENTRY_CONN(conn)->socks_request) {
 +        /* broken, don't send a socks reply back */
 +        TO_ENTRY_CONN(conn)->socks_request->has_finished = 1;
 +      }
 +    }
 +    connection_close_immediate(conn); /* Don't flush; connection is dead. */
 +    /*
 +     * This can bypass normal channel checking since we did
 +     * connection_or_notify_error() above.
 +     */
 +    connection_mark_for_close_internal(conn);
 +    return -1;
 +  }
 +  n_read += buf_datalen(conn->inbuf) - before;
 +  if (CONN_IS_EDGE(conn) && try_to_read != max_to_read) {
 +    /* instruct it not to try to package partial cells. */
 +    if (connection_process_inbuf(conn, 0) < 0) {
 +      return -1;
 +    }
 +    if (!conn->marked_for_close &&
 +        connection_is_reading(conn) &&
 +        !conn->inbuf_reached_eof &&
 +        max_to_read > 0)
 +      goto loop_again; /* try reading again, in case more is here now */
 +  }
 +  /* one last try, packaging partial cells and all. */
 +  if (!conn->marked_for_close &&
 +      connection_process_inbuf(conn, 1) < 0) {
 +    return -1;
 +  }
 +  if (conn->linked_conn) {
 +    /* The other side's handle_write() will never actually get called, so
 +     * we need to invoke the appropriate callbacks ourself. */
 +    connection_t *linked = conn->linked_conn;
 +
 +    if (n_read) {
 +      /* Probably a no-op, since linked conns typically don't count for
 +       * bandwidth rate limiting. But do it anyway so we can keep stats
 +       * accurately. Note that since we read the bytes from conn, and
 +       * we're writing the bytes onto the linked connection, we count
 +       * these as <i>written</i> bytes. */
 +      connection_buckets_decrement(linked, approx_time(), 0, n_read);
 +
 +      if (connection_flushed_some(linked) < 0)
 +        connection_mark_for_close(linked);
 +      if (!connection_wants_to_flush(linked))
 +        connection_finished_flushing(linked);
 +    }
 +
 +    if (!buf_datalen(linked->outbuf) && conn->active_on_link)
 +      connection_stop_reading_from_linked_conn(conn);
 +  }
 +  /* If we hit the EOF, call connection_reached_eof(). */
 +  if (!conn->marked_for_close &&
 +      conn->inbuf_reached_eof &&
 +      connection_reached_eof(conn) < 0) {
 +    return -1;
 +  }
 +  return 0;
 +}
 +
 +/* DOCDOC connection_handle_read */
 +int
 +connection_handle_read(connection_t *conn)
 +{
 +  int res;
 +  update_current_time(time(NULL));
 +  res = connection_handle_read_impl(conn);
 +  return res;
 +}
 +
 +/** Pull in new bytes from conn-\>s or conn-\>linked_conn onto conn-\>inbuf,
 + * either directly or via TLS. Reduce the token buckets by the number of bytes
 + * read.
 + *
 + * If *max_to_read is -1, then decide it ourselves, else go with the
 + * value passed to us. When returning, if it's changed, subtract the
 + * number of bytes we read from *max_to_read.
 + *
 + * Return -1 if we want to break conn, else return 0.
 + */
 +static int
 +connection_buf_read_from_socket(connection_t *conn, ssize_t *max_to_read,
 +                       int *socket_error)
 +{
 +  int result;
 +  ssize_t at_most = *max_to_read;
 +  size_t slack_in_buf, more_to_read;
 +  size_t n_read = 0, n_written = 0;
 +
 +  if (at_most == -1) { /* we need to initialize it */
 +    /* how many bytes are we allowed to read? */
 +    at_most = connection_bucket_read_limit(conn, approx_time());
 +  }
 +
 +  slack_in_buf = buf_slack(conn->inbuf);
 + again:
 +  if ((size_t)at_most > slack_in_buf && slack_in_buf >= 1024) {
 +    more_to_read = at_most - slack_in_buf;
 +    at_most = slack_in_buf;
 +  } else {
 +    more_to_read = 0;
 +  }
 +
 +  if (connection_speaks_cells(conn) &&
 +      conn->state > OR_CONN_STATE_PROXY_HANDSHAKING) {
 +    int pending;
 +    or_connection_t *or_conn = TO_OR_CONN(conn);
 +    size_t initial_size;
 +    if (conn->state == OR_CONN_STATE_TLS_HANDSHAKING ||
 +        conn->state == OR_CONN_STATE_TLS_CLIENT_RENEGOTIATING) {
 +      /* continue handshaking even if global token bucket is empty */
 +      return connection_tls_continue_handshake(or_conn);
 +    }
 +
 +    log_debug(LD_NET,
 +              "%d: starting, inbuf_datalen %ld (%d pending in tls object)."
 +              " at_most %ld.",
 +              (int)conn->s,(long)buf_datalen(conn->inbuf),
 +              tor_tls_get_pending_bytes(or_conn->tls), (long)at_most);
 +
 +    initial_size = buf_datalen(conn->inbuf);
 +    /* else open, or closing */
 +    result = buf_read_from_tls(conn->inbuf, or_conn->tls, at_most);
 +    if (TOR_TLS_IS_ERROR(result) || result == TOR_TLS_CLOSE)
 +      or_conn->tls_error = result;
 +    else
 +      or_conn->tls_error = 0;
 +
 +    switch (result) {
 +      case TOR_TLS_CLOSE:
 +      case TOR_TLS_ERROR_IO:
 +        log_debug(LD_NET,"TLS connection closed %son read. Closing. "
 +                 "(Nickname %s, address %s)",
 +                 result == TOR_TLS_CLOSE ? "cleanly " : "",
 +                 or_conn->nickname ? or_conn->nickname : "not set",
 +                 conn->address);
 +        return result;
 +      CASE_TOR_TLS_ERROR_ANY_NONIO:
 +        log_debug(LD_NET,"tls error [%s]. breaking (nickname %s, address %s).",
 +                 tor_tls_err_to_string(result),
 +                 or_conn->nickname ? or_conn->nickname : "not set",
 +                 conn->address);
 +        return result;
 +      case TOR_TLS_WANTWRITE:
 +        connection_start_writing(conn);
 +        return 0;
 +      case TOR_TLS_WANTREAD:
 +        if (conn->in_connection_handle_write) {
 +          /* We've been invoked from connection_handle_write, because we're
 +           * waiting for a TLS renegotiation, the renegotiation started, and
 +           * SSL_read returned WANTWRITE.  But now SSL_read is saying WANTREAD
 +           * again.  Stop waiting for write events now, or else we'll
 +           * busy-loop until data arrives for us to read.
 +           * XXX: remove this when v2 handshakes support is dropped. */
 +          connection_stop_writing(conn);
 +          if (!connection_is_reading(conn))
 +            connection_start_reading(conn);
 +        }
 +        /* we're already reading, one hopes */
 +        break;
 +      case TOR_TLS_DONE: /* no data read, so nothing to process */
 +        break; /* so we call bucket_decrement below */
 +      default:
 +        break;
 +    }
 +    pending = tor_tls_get_pending_bytes(or_conn->tls);
 +    if (pending) {
 +      /* If we have any pending bytes, we read them now.  This *can*
 +       * take us over our read allotment, but really we shouldn't be
 +       * believing that SSL bytes are the same as TCP bytes anyway. */
 +      int r2 = buf_read_from_tls(conn->inbuf, or_conn->tls, pending);
 +      if (BUG(r2<0)) {
 +        log_warn(LD_BUG, "apparently, reading pending bytes can fail.");
 +        return -1;
 +      }
 +    }
 +    result = (int)(buf_datalen(conn->inbuf)-initial_size);
 +    tor_tls_get_n_raw_bytes(or_conn->tls, &n_read, &n_written);
 +    log_debug(LD_GENERAL, "After TLS read of %d: %ld read, %ld written",
 +              result, (long)n_read, (long)n_written);
 +  } else if (conn->linked) {
 +    if (conn->linked_conn) {
 +      result = buf_move_to_buf(conn->inbuf, conn->linked_conn->outbuf,
 +                               &conn->linked_conn->outbuf_flushlen);
++      if (BUG(result<0)) {
++        log_warn(LD_BUG, "reading from linked connection buffer failed.");
++        return -1;
++      }
 +    } else {
 +      result = 0;
 +    }
 +    //log_notice(LD_GENERAL, "Moved %d bytes on an internal link!", result);
 +    /* If the other side has disappeared, or if it's been marked for close and
 +     * we flushed its outbuf, then we should set our inbuf_reached_eof. */
 +    if (!conn->linked_conn ||
 +        (conn->linked_conn->marked_for_close &&
 +         buf_datalen(conn->linked_conn->outbuf) == 0))
 +      conn->inbuf_reached_eof = 1;
 +
 +    n_read = (size_t) result;
 +  } else {
 +    /* !connection_speaks_cells, !conn->linked_conn. */
 +    int reached_eof = 0;
 +    CONN_LOG_PROTECT(conn,
 +                     result = buf_read_from_socket(conn->inbuf, conn->s,
 +                                                   at_most,
 +                                                   &reached_eof,
 +                                                   socket_error));
 +    if (reached_eof)
 +      conn->inbuf_reached_eof = 1;
 +
 +//  log_fn(LOG_DEBUG,"read_to_buf returned %d.",read_result);
 +
 +    if (result < 0)
 +      return -1;
 +    n_read = (size_t) result;
 +  }
 +
 +  if (n_read > 0) {
 +     /* change *max_to_read */
 +    *max_to_read = at_most - n_read;
 +
 +    /* Update edge_conn->n_read */
 +    if (conn->type == CONN_TYPE_AP) {
 +      edge_connection_t *edge_conn = TO_EDGE_CONN(conn);
 +
 +      /* Check for overflow: */
 +      if (PREDICT_LIKELY(UINT32_MAX - edge_conn->n_read > n_read))
 +        edge_conn->n_read += (int)n_read;
 +      else
 +        edge_conn->n_read = UINT32_MAX;
 +    }
 +
 +    /* If CONN_BW events are enabled, update conn->n_read_conn_bw for
 +     * OR/DIR/EXIT connections, checking for overflow. */
 +    if (get_options()->TestingEnableConnBwEvent &&
 +       (conn->type == CONN_TYPE_OR ||
 +        conn->type == CONN_TYPE_DIR ||
 +        conn->type == CONN_TYPE_EXIT)) {
 +      if (PREDICT_LIKELY(UINT32_MAX - conn->n_read_conn_bw > n_read))
 +        conn->n_read_conn_bw += (int)n_read;
 +      else
 +        conn->n_read_conn_bw = UINT32_MAX;
 +    }
 +  }
 +
 +  connection_buckets_decrement(conn, approx_time(), n_read, n_written);
 +
 +  if (more_to_read && result == at_most) {
 +    slack_in_buf = buf_slack(conn->inbuf);
 +    at_most = more_to_read;
 +    goto again;
 +  }
 +
 +  /* Call even if result is 0, since the global read bucket may
 +   * have reached 0 on a different conn, and this connection needs to
 +   * know to stop reading. */
 +  connection_consider_empty_read_buckets(conn);
 +  if (n_written > 0 && connection_is_writing(conn))
 +    connection_consider_empty_write_buckets(conn);
 +
 +  return 0;
 +}
 +
 +/** A pass-through to fetch_from_buf. */
 +int
 +connection_buf_get_bytes(char *string, size_t len, connection_t *conn)
 +{
 +  return buf_get_bytes(conn->inbuf, string, len);
 +}
 +
 +/** As buf_get_line(), but read from a connection's input buffer. */
 +int
 +connection_buf_get_line(connection_t *conn, char *data,
 +                               size_t *data_len)
 +{
 +  return buf_get_line(conn->inbuf, data, data_len);
 +}
 +
 +/** As fetch_from_buf_http, but fetches from a connection's input buffer_t as
 + * appropriate. */
 +int
 +connection_fetch_from_buf_http(connection_t *conn,
 +                               char **headers_out, size_t max_headerlen,
 +                               char **body_out, size_t *body_used,
 +                               size_t max_bodylen, int force_complete)
 +{
 +  return fetch_from_buf_http(conn->inbuf, headers_out, max_headerlen,
 +                             body_out, body_used, max_bodylen, force_complete);
 +}
 +
 +/** Return conn-\>outbuf_flushlen: how many bytes conn wants to flush
 + * from its outbuf. */
 +int
 +connection_wants_to_flush(connection_t *conn)
 +{
 +  return conn->outbuf_flushlen > 0;
 +}
 +
 +/** Are there too many bytes on edge connection <b>conn</b>'s outbuf to
 + * send back a relay-level sendme yet? Return 1 if so, 0 if not. Used by
 + * connection_edge_consider_sending_sendme().
 + */
 +int
 +connection_outbuf_too_full(connection_t *conn)
 +{
 +  return (conn->outbuf_flushlen > 10*CELL_PAYLOAD_SIZE);
 +}
 +
 +/**
 + * On Windows Vista and Windows 7, tune the send buffer size according to a
 + * hint from the OS.
 + *
 + * This should help fix slow upload rates.
 + */
 +static void
 +update_send_buffer_size(tor_socket_t sock)
 +{
 +#ifdef _WIN32
 +  /* We only do this on Vista and 7, because earlier versions of Windows
 +   * don't have the SIO_IDEAL_SEND_BACKLOG_QUERY functionality, and on
 +   * later versions it isn't necessary. */
 +  static int isVistaOr7 = -1;
 +  if (isVistaOr7 == -1) {
 +    isVistaOr7 = 0;
 +    OSVERSIONINFO osvi = { 0 };
 +    osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
 +    GetVersionEx(&osvi);
 +    if (osvi.dwMajorVersion == 6 && osvi.dwMinorVersion < 2)
 +      isVistaOr7 = 1;
 +  }
 +  if (!isVistaOr7)
 +    return;
 +  if (get_options()->ConstrainedSockets)
 +    return;
 +  ULONG isb = 0;
 +  DWORD bytesReturned = 0;
 +  if (!WSAIoctl(sock, SIO_IDEAL_SEND_BACKLOG_QUERY, NULL, 0,
 +      &isb, sizeof(isb), &bytesReturned, NULL, NULL)) {
 +    setsockopt(sock, SOL_SOCKET, SO_SNDBUF, (const char*)&isb, sizeof(isb));
 +  }
 +#else
 +  (void) sock;
 +#endif
 +}
 +
 +/** Try to flush more bytes onto <b>conn</b>-\>s.
 + *
 + * This function is called in connection_handle_write(), which gets
 + * called from conn_write_callback() in main.c when libevent tells us
 + * that <b>conn</b> wants to write.
 + *
 + * Update <b>conn</b>-\>timestamp_last_write_allowed to now, and call flush_buf
 + * or flush_buf_tls appropriately. If it succeeds and there are no more
 + * more bytes on <b>conn</b>-\>outbuf, then call connection_finished_flushing
 + * on it too.
 + *
 + * If <b>force</b>, then write as many bytes as possible, ignoring bandwidth
 + * limits.  (Used for flushing messages to controller connections on fatal
 + * errors.)
 + *
 + * Mark the connection and return -1 if you want to close it, else
 + * return 0.
 + */
 +static int
 +connection_handle_write_impl(connection_t *conn, int force)
 +{
 +  int e;
 +  socklen_t len=(socklen_t)sizeof(e);
 +  int result;
 +  ssize_t max_to_write;
 +  time_t now = approx_time();
 +  size_t n_read = 0, n_written = 0;
 +  int dont_stop_writing = 0;
 +
 +  tor_assert(!connection_is_listener(conn));
 +
 +  if (conn->marked_for_close || !SOCKET_OK(conn->s))
 +    return 0; /* do nothing */
 +
 +  if (conn->in_flushed_some) {
 +    log_warn(LD_BUG, "called recursively from inside conn->in_flushed_some");
 +    return 0;
 +  }
 +
 +  conn->timestamp_last_write_allowed = now;
 +
 +  connection_bucket_refill_single(conn, monotime_coarse_get_stamp());
 +
 +  /* Sometimes, "writable" means "connected". */
 +  if (connection_state_is_connecting(conn)) {
 +    if (getsockopt(conn->s, SOL_SOCKET, SO_ERROR, (void*)&e, &len) < 0) {
 +      log_warn(LD_BUG, "getsockopt() syscall failed");
 +      if (conn->type == CONN_TYPE_OR) {
 +        or_connection_t *orconn = TO_OR_CONN(conn);
 +        connection_or_close_for_error(orconn, 0);
 +      } else {
 +        if (CONN_IS_EDGE(conn)) {
 +          connection_edge_end_errno(TO_EDGE_CONN(conn));
 +        }
 +        connection_mark_for_close(conn);
 +      }
 +      return -1;
 +    }
 +    if (e) {
 +      /* some sort of error, but maybe just inprogress still */
 +      if (!ERRNO_IS_CONN_EINPROGRESS(e)) {
 +        log_info(LD_NET,"in-progress connect failed. Removing. (%s)",
 +                 tor_socket_strerror(e));
 +        if (CONN_IS_EDGE(conn))
 +          connection_edge_end_errno(TO_EDGE_CONN(conn));
 +        if (conn->type == CONN_TYPE_OR)
 +          connection_or_notify_error(TO_OR_CONN(conn),
 +                                     errno_to_orconn_end_reason(e),
 +                                     tor_socket_strerror(e));
 +
 +        connection_close_immediate(conn);
 +        /*
 +         * This can bypass normal channel checking since we did
 +         * connection_or_notify_error() above.
 +         */
 +        connection_mark_for_close_internal(conn);
 +        return -1;
 +      } else {
 +        return 0; /* no change, see if next time is better */
 +      }
 +    }
 +    /* The connection is successful. */
 +    if (connection_finished_connecting(conn)<0)
 +      return -1;
 +  }
 +
 +  max_to_write = force ? (ssize_t)conn->outbuf_flushlen
 +    : connection_bucket_write_limit(conn, now);
 +
 +  if (connection_speaks_cells(conn) &&
 +      conn->state > OR_CONN_STATE_PROXY_HANDSHAKING) {
 +    or_connection_t *or_conn = TO_OR_CONN(conn);
 +    size_t initial_size;
 +    if (conn->state == OR_CONN_STATE_TLS_HANDSHAKING ||
 +        conn->state == OR_CONN_STATE_TLS_CLIENT_RENEGOTIATING) {
 +      connection_stop_writing(conn);
 +      if (connection_tls_continue_handshake(or_conn) < 0) {
 +        /* Don't flush; connection is dead. */
 +        connection_or_notify_error(or_conn,
 +                                   END_OR_CONN_REASON_MISC,
 +                                   "TLS error in connection_tls_"
 +                                   "continue_handshake()");
 +        connection_close_immediate(conn);
 +        /*
 +         * This can bypass normal channel checking since we did
 +         * connection_or_notify_error() above.
 +         */
 +        connection_mark_for_close_internal(conn);
 +        return -1;
 +      }
 +      return 0;
 +    } else if (conn->state == OR_CONN_STATE_TLS_SERVER_RENEGOTIATING) {
 +      return connection_handle_read(conn);
 +    }
 +
 +    /* else open, or closing */
 +    initial_size = buf_datalen(conn->outbuf);
 +    result = buf_flush_to_tls(conn->outbuf, or_conn->tls,
 +                           max_to_write, &conn->outbuf_flushlen);
 +
 +    if (result >= 0)
 +      update_send_buffer_size(conn->s);
 +
 +    /* If we just flushed the last bytes, tell the channel on the
 +     * or_conn to check if it needs to geoip_change_dirreq_state() */
 +    /* XXXX move this to flushed_some or finished_flushing -NM */
 +    if (buf_datalen(conn->outbuf) == 0 && or_conn->chan)
 +      channel_notify_flushed(TLS_CHAN_TO_BASE(or_conn->chan));
 +
 +    switch (result) {
 +      CASE_TOR_TLS_ERROR_ANY:
 +      case TOR_TLS_CLOSE:
 +        log_info(LD_NET, result != TOR_TLS_CLOSE ?
 +                 "tls error. breaking.":"TLS connection closed on flush");
 +        /* Don't flush; connection is dead. */
 +        connection_or_notify_error(or_conn,
 +                                   END_OR_CONN_REASON_MISC,
 +                                   result != TOR_TLS_CLOSE ?
 +                                     "TLS error in during flush" :
 +                                     "TLS closed during flush");
 +        connection_close_immediate(conn);
 +        /*
 +         * This can bypass normal channel checking since we did
 +         * connection_or_notify_error() above.
 +         */
 +        connection_mark_for_close_internal(conn);
 +        return -1;
 +      case TOR_TLS_WANTWRITE:
 +        log_debug(LD_NET,"wanted write.");
 +        /* we're already writing */
 +        dont_stop_writing = 1;
 +        break;
 +      case TOR_TLS_WANTREAD:
 +        /* Make sure to avoid a loop if the receive buckets are empty. */
 +        log_debug(LD_NET,"wanted read.");
 +        if (!connection_is_reading(conn)) {
 +          connection_write_bw_exhausted(conn, true);
 +          /* we'll start reading again when we get more tokens in our
 +           * read bucket; then we'll start writing again too.
 +           */
 +        }
 +        /* else no problem, we're already reading */
 +        return 0;
 +      /* case TOR_TLS_DONE:
 +       * for TOR_TLS_DONE, fall through to check if the flushlen
 +       * is empty, so we can stop writing.
 +       */
 +    }
 +
 +    tor_tls_get_n_raw_bytes(or_conn->tls, &n_read, &n_written);
 +    log_debug(LD_GENERAL, "After TLS write of %d: %ld read, %ld written",
 +              result, (long)n_read, (long)n_written);
 +    or_conn->bytes_xmitted += result;
 +    or_conn->bytes_xmitted_by_tls += n_written;
 +    /* So we notice bytes were written even on error */
 +    /* XXXX This cast is safe since we can never write INT_MAX bytes in a
 +     * single set of TLS operations. But it looks kinda ugly. If we refactor
 +     * the *_buf_tls functions, we should make them return ssize_t or size_t
 +     * or something. */
 +    result = (int)(initial_size-buf_datalen(conn->outbuf));
 +  } else {
 +    CONN_LOG_PROTECT(conn,
 +                     result = buf_flush_to_socket(conn->outbuf, conn->s,
 +                                        max_to_write, &conn->outbuf_flushlen));
 +    if (result < 0) {
 +      if (CONN_IS_EDGE(conn))
 +        connection_edge_end_errno(TO_EDGE_CONN(conn));
 +      if (conn->type == CONN_TYPE_AP) {
 +        /* writing failed; we couldn't send a SOCKS reply if we wanted to */
 +        TO_ENTRY_CONN(conn)->socks_request->has_finished = 1;
 +      }
 +
 +      connection_close_immediate(conn); /* Don't flush; connection is dead. */
 +      connection_mark_for_close(conn);
 +      return -1;
 +    }
 +    update_send_buffer_size(conn->s);
 +    n_written = (size_t) result;
 +  }
 +
 +  if (n_written && conn->type == CONN_TYPE_AP) {
 +    edge_connection_t *edge_conn = TO_EDGE_CONN(conn);
 +
 +    /* Check for overflow: */
 +    if (PREDICT_LIKELY(UINT32_MAX - edge_conn->n_written > n_written))
 +      edge_conn->n_written += (int)n_written;
 +    else
 +      edge_conn->n_written = UINT32_MAX;
 +  }
 +
 +  /* If CONN_BW events are enabled, update conn->n_written_conn_bw for
 +   * OR/DIR/EXIT connections, checking for overflow. */
 +  if (n_written && get_options()->TestingEnableConnBwEvent &&
 +     (conn->type == CONN_TYPE_OR ||
 +      conn->type == CONN_TYPE_DIR ||
 +      conn->type == CONN_TYPE_EXIT)) {
 +    if (PREDICT_LIKELY(UINT32_MAX - conn->n_written_conn_bw > n_written))
 +      conn->n_written_conn_bw += (int)n_written;
 +    else
 +      conn->n_written_conn_bw = UINT32_MAX;
 +  }
 +
 +  connection_buckets_decrement(conn, approx_time(), n_read, n_written);
 +
 +  if (result > 0) {
 +    /* If we wrote any bytes from our buffer, then call the appropriate
 +     * functions. */
 +    if (connection_flushed_some(conn) < 0) {
 +      if (connection_speaks_cells(conn)) {
 +        connection_or_notify_error(TO_OR_CONN(conn),
 +                                   END_OR_CONN_REASON_MISC,
 +                                   "Got error back from "
 +                                   "connection_flushed_some()");
 +      }
 +
 +      /*
 +       * This can bypass normal channel checking since we did
 +       * connection_or_notify_error() above.
 +       */
 +      connection_mark_for_close_internal(conn);
 +    }
 +  }
 +
 +  if (!connection_wants_to_flush(conn) &&
 +      !dont_stop_writing) { /* it's done flushing */
 +    if (connection_finished_flushing(conn) < 0) {
 +      /* already marked */
 +      return -1;
 +    }
 +    return 0;
 +  }
 +
 +  /* Call even if result is 0, since the global write bucket may
 +   * have reached 0 on a different conn, and this connection needs to
 +   * know to stop writing. */
 +  connection_consider_empty_write_buckets(conn);
 +  if (n_read > 0 && connection_is_reading(conn))
 +    connection_consider_empty_read_buckets(conn);
 +
 +  return 0;
 +}
 +
 +/* DOCDOC connection_handle_write */
 +int
 +connection_handle_write(connection_t *conn, int force)
 +{
 +    int res;
 +    update_current_time(time(NULL));
 +    /* connection_handle_write_impl() might call connection_handle_read()
 +     * if we're in the middle of a v2 handshake, in which case it needs this
 +     * flag set. */
 +    conn->in_connection_handle_write = 1;
 +    res = connection_handle_write_impl(conn, force);
 +    conn->in_connection_handle_write = 0;
 +    return res;
 +}
 +
 +/**
 + * Try to flush data that's waiting for a write on <b>conn</b>.  Return
 + * -1 on failure, 0 on success.
 + *
 + * Don't use this function for regular writing; the buffers
 + * system should be good enough at scheduling writes there.  Instead, this
 + * function is for cases when we're about to exit or something and we want
 + * to report it right away.
 + */
 +int
 +connection_flush(connection_t *conn)
 +{
 +  return connection_handle_write(conn, 1);
 +}
 +
 +/** Helper for connection_write_to_buf_impl and connection_write_buf_to_buf:
 + *
 + * Return true iff it is okay to queue bytes on <b>conn</b>'s outbuf for
 + * writing.
 + */
 +static int
 +connection_may_write_to_buf(connection_t *conn)
 +{
 +  /* if it's marked for close, only allow write if we mean to flush it */
 +  if (conn->marked_for_close && !conn->hold_open_until_flushed)
 +    return 0;
 +
 +  return 1;
 +}
 +
 +/** Helper for connection_write_to_buf_impl and connection_write_buf_to_buf:
 + *
 + * Called when an attempt to add bytes on <b>conn</b>'s outbuf has failed;
 + * mark the connection and warn as appropriate.
 + */
 +static void
 +connection_write_to_buf_failed(connection_t *conn)
 +{
 +  if (CONN_IS_EDGE(conn)) {
 +    /* if it failed, it means we have our package/delivery windows set
 +       wrong compared to our max outbuf size. close the whole circuit. */
 +    log_warn(LD_NET,
 +             "write_to_buf failed. Closing circuit (fd %d).", (int)conn->s);
 +    circuit_mark_for_close(circuit_get_by_edge_conn(TO_EDGE_CONN(conn)),
 +                           END_CIRC_REASON_INTERNAL);
 +  } else if (conn->type == CONN_TYPE_OR) {
 +    or_connection_t *orconn = TO_OR_CONN(conn);
 +    log_warn(LD_NET,
 +             "write_to_buf failed on an orconn; notifying of error "
 +             "(fd %d)", (int)(conn->s));
 +    connection_or_close_for_error(orconn, 0);
 +  } else {
 +    log_warn(LD_NET,
 +             "write_to_buf failed. Closing connection (fd %d).",
 +             (int)conn->s);
 +    connection_mark_for_close(conn);
 +  }
 +}
 +
 +/** Helper for connection_write_to_buf_impl and connection_write_buf_to_buf:
 + *
 + * Called when an attempt to add bytes on <b>conn</b>'s outbuf has succeeded:
 + * record the number of bytes added.
 + */
 +static void
 +connection_write_to_buf_commit(connection_t *conn, size_t len)
 +{
 +  /* If we receive optimistic data in the EXIT_CONN_STATE_RESOLVING
 +   * state, we don't want to try to write it right away, since
 +   * conn->write_event won't be set yet.  Otherwise, write data from
 +   * this conn as the socket is available. */
 +  if (conn->write_event) {
 +    connection_start_writing(conn);
 +  }
 +  conn->outbuf_flushlen += len;
 +}
 +
 +/** Append <b>len</b> bytes of <b>string</b> onto <b>conn</b>'s
 + * outbuf, and ask it to start writing.
 + *
 + * If <b>zlib</b> is nonzero, this is a directory connection that should get
 + * its contents compressed or decompressed as they're written.  If zlib is
 + * negative, this is the last data to be compressed, and the connection's zlib
 + * state should be flushed.
 + */
 +MOCK_IMPL(void,
 +connection_write_to_buf_impl_,(const char *string, size_t len,
 +                               connection_t *conn, int zlib))
 +{
 +  /* XXXX This function really needs to return -1 on failure. */
 +  int r;
 +  if (!len && !(zlib<0))
 +    return;
 +
 +  if (!connection_may_write_to_buf(conn))
 +    return;
 +
 +  size_t written;
 +
 +  if (zlib) {
 +    size_t old_datalen = buf_datalen(conn->outbuf);
 +    dir_connection_t *dir_conn = TO_DIR_CONN(conn);
 +    int done = zlib < 0;
 +    CONN_LOG_PROTECT(conn, r = buf_add_compress(conn->outbuf,
 +                                                dir_conn->compress_state,
 +                                                string, len, done));
 +    written = buf_datalen(conn->outbuf) - old_datalen;
 +  } else {
 +    CONN_LOG_PROTECT(conn, r = buf_add(conn->outbuf, string, len));
 +    written = len;
 +  }
 +  if (r < 0) {
 +    connection_write_to_buf_failed(conn);
 +    return;
 +  }
 +  connection_write_to_buf_commit(conn, written);
 +}
 +
 +void
 +connection_buf_add_compress(const char *string, size_t len,
 +                            dir_connection_t *conn, int done)
 +{
 +  connection_write_to_buf_impl_(string, len, TO_CONN(conn), done ? -1 : 1);
 +}
 +
 +/**
 + * Add all bytes from <b>buf</b> to <b>conn</b>'s outbuf, draining them
 + * from <b>buf</b>. (If the connection is marked and will soon be closed,
 + * nothing is drained.)
 + */
 +void
 +connection_buf_add_buf(connection_t *conn, buf_t *buf)
 +{
 +  tor_assert(conn);
 +  tor_assert(buf);
 +  size_t len = buf_datalen(buf);
 +  if (len == 0)
 +    return;
 +
 +  if (!connection_may_write_to_buf(conn))
 +    return;
 +
 +  buf_move_all(conn->outbuf, buf);
 +  connection_write_to_buf_commit(conn, len);
 +}
 +
 +#define CONN_GET_ALL_TEMPLATE(var, test) \
 +  STMT_BEGIN \
 +    smartlist_t *conns = get_connection_array();   \
 +    smartlist_t *ret_conns = smartlist_new();     \
 +    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, var) { \
 +      if (var && (test) && !var->marked_for_close) \
 +        smartlist_add(ret_conns, var); \
 +    } SMARTLIST_FOREACH_END(var);                                            \
 +    return ret_conns; \
 +  STMT_END
 +
 +/* Return a list of connections that aren't close and matches the given type
 + * and state. The returned list can be empty and must be freed using
 + * smartlist_free(). The caller does NOT have ownership of the objects in the
 + * list so it must not free them nor reference them as they can disappear. */
 +smartlist_t *
 +connection_list_by_type_state(int type, int state)
 +{
 +  CONN_GET_ALL_TEMPLATE(conn, (conn->type == type && conn->state == state));
 +}
 +
 +/* Return a list of connections that aren't close and matches the given type
 + * and purpose. The returned list can be empty and must be freed using
 + * smartlist_free(). The caller does NOT have ownership of the objects in the
 + * list so it must not free them nor reference them as they can disappear. */
 +smartlist_t *
 +connection_list_by_type_purpose(int type, int purpose)
 +{
 +  CONN_GET_ALL_TEMPLATE(conn,
 +                        (conn->type == type && conn->purpose == purpose));
 +}
 +
 +/** Return a connection_t * from get_connection_array() that satisfies test on
 + * var, and that is not marked for close. */
 +#define CONN_GET_TEMPLATE(var, test)               \
 +  STMT_BEGIN                                       \
 +    smartlist_t *conns = get_connection_array();   \
 +    SMARTLIST_FOREACH(conns, connection_t *, var,  \
 +    {                                              \
 +      if (var && (test) && !var->marked_for_close) \
 +        return var;                                \
 +    });                                            \
 +    return NULL;                                   \
 +  STMT_END
 +
 +/** Return a connection with given type, address, port, and purpose;
 + * or NULL if no such connection exists (or if all such connections are marked
 + * for close). */
 +MOCK_IMPL(connection_t *,
 +connection_get_by_type_addr_port_purpose,(int type,
 +                                         const tor_addr_t *addr, uint16_t port,
 +                                         int purpose))
 +{
 +  CONN_GET_TEMPLATE(conn,
 +       (conn->type == type &&
 +        tor_addr_eq(&conn->addr, addr) &&
 +        conn->port == port &&
 +        conn->purpose == purpose));
 +}
 +
 +/** Return the stream with id <b>id</b> if it is not already marked for
 + * close.
 + */
 +connection_t *
 +connection_get_by_global_id(uint64_t id)
 +{
 +  CONN_GET_TEMPLATE(conn, conn->global_identifier == id);
 +}
 +
 +/** Return a connection of type <b>type</b> that is not marked for close.
 + */
 +connection_t *
 +connection_get_by_type(int type)
 +{
 +  CONN_GET_TEMPLATE(conn, conn->type == type);
 +}
 +
 +/** Return a connection of type <b>type</b> that is in state <b>state</b>,
 + * and that is not marked for close.
 + */
 +connection_t *
 +connection_get_by_type_state(int type, int state)
 +{
 +  CONN_GET_TEMPLATE(conn, conn->type == type && conn->state == state);
 +}
 +
 +/** Return a connection of type <b>type</b> that has rendquery equal
 + * to <b>rendquery</b>, and that is not marked for close. If state
 + * is non-zero, conn must be of that state too.
 + */
 +connection_t *
 +connection_get_by_type_state_rendquery(int type, int state,
 +                                       const char *rendquery)
 +{
 +  tor_assert(type == CONN_TYPE_DIR ||
 +             type == CONN_TYPE_AP || type == CONN_TYPE_EXIT);
 +  tor_assert(rendquery);
 +
 +  CONN_GET_TEMPLATE(conn,
 +       (conn->type == type &&
 +        (!state || state == conn->state)) &&
 +        (
 +         (type == CONN_TYPE_DIR &&
 +          TO_DIR_CONN(conn)->rend_data &&
 +          !rend_cmp_service_ids(rendquery,
 +                    rend_data_get_address(TO_DIR_CONN(conn)->rend_data)))
 +         ||
 +              (CONN_IS_EDGE(conn) &&
 +               TO_EDGE_CONN(conn)->rend_data &&
 +               !rend_cmp_service_ids(rendquery,
 +                    rend_data_get_address(TO_EDGE_CONN(conn)->rend_data)))
 +         ));
 +}
 +
 +/** Return a new smartlist of dir_connection_t * from get_connection_array()
 + * that satisfy conn_test on connection_t *conn_var, and dirconn_test on
 + * dir_connection_t *dirconn_var. conn_var must be of CONN_TYPE_DIR and not
 + * marked for close to be included in the list. */
 +#define DIR_CONN_LIST_TEMPLATE(conn_var, conn_test,             \
 +                               dirconn_var, dirconn_test)       \
 +  STMT_BEGIN                                                    \
 +    smartlist_t *conns = get_connection_array();                \
 +    smartlist_t *dir_conns = smartlist_new();                   \
 +    SMARTLIST_FOREACH_BEGIN(conns, connection_t *, conn_var) {  \
 +      if (conn_var && (conn_test)                               \
 +          && conn_var->type == CONN_TYPE_DIR                    \
 +          && !conn_var->marked_for_close) {                     \
 +        dir_connection_t *dirconn_var = TO_DIR_CONN(conn_var);  \
 +        if (dirconn_var && (dirconn_test)) {                    \
 +          smartlist_add(dir_conns, dirconn_var);                \
 +        }                                                       \
 +      }                                                         \
 +    } SMARTLIST_FOREACH_END(conn_var);                          \
 +    return dir_conns;                                           \
 +  STMT_END
 +
 +/** Return a list of directory connections that are fetching the item
 + * described by <b>purpose</b>/<b>resource</b>. If there are none,
 + * return an empty list. This list must be freed using smartlist_free,
 + * but the pointers in it must not be freed.
 + * Note that this list should not be cached, as the pointers in it can be
 + * freed if their connections close. */
 +smartlist_t *
 +connection_dir_list_by_purpose_and_resource(
 +                                            int purpose,
 +                                            const char *resource)
 +{
 +  DIR_CONN_LIST_TEMPLATE(conn,
 +                         conn->purpose == purpose,
 +                         dirconn,
 +                         0 == strcmp_opt(resource,
 +                                         dirconn->requested_resource));
 +}
 +
 +/** Return a list of directory connections that are fetching the item
 + * described by <b>purpose</b>/<b>resource</b>/<b>state</b>. If there are
 + * none, return an empty list. This list must be freed using smartlist_free,
 + * but the pointers in it must not be freed.
 + * Note that this list should not be cached, as the pointers in it can be
 + * freed if their connections close. */
 +smartlist_t *
 +connection_dir_list_by_purpose_resource_and_state(
 +                                                  int purpose,
 +                                                  const char *resource,
 +                                                  int state)
 +{
 +  DIR_CONN_LIST_TEMPLATE(conn,
 +                         conn->purpose == purpose && conn->state == state,
 +                         dirconn,
 +                         0 == strcmp_opt(resource,
 +                                         dirconn->requested_resource));
 +}
 +
 +#undef DIR_CONN_LIST_TEMPLATE
 +
 +/** Return an arbitrary active OR connection that isn't <b>this_conn</b>.
 + *
 + * We use this to guess if we should tell the controller that we
 + * didn't manage to connect to any of our bridges. */
 +static connection_t *
 +connection_get_another_active_or_conn(const or_connection_t *this_conn)
 +{
 +  CONN_GET_TEMPLATE(conn,
 +                    conn != TO_CONN(this_conn) && conn->type == CONN_TYPE_OR);
 +}
 +
 +/** Return 1 if there are any active OR connections apart from
 + * <b>this_conn</b>.
 + *
 + * We use this to guess if we should tell the controller that we
 + * didn't manage to connect to any of our bridges. */
 +int
 +any_other_active_or_conns(const or_connection_t *this_conn)
 +{
 +  connection_t *conn = connection_get_another_active_or_conn(this_conn);
 +  if (conn != NULL) {
 +    log_debug(LD_DIR, "%s: Found an OR connection: %s",
 +              __func__, conn->address);
 +    return 1;
 +  }
 +
 +  return 0;
 +}
 +
 +#undef CONN_GET_TEMPLATE
 +
 +/** Return 1 if <b>conn</b> is a listener conn, else return 0. */
 +int
 +connection_is_listener(connection_t *conn)
 +{
 +  if (conn->type == CONN_TYPE_OR_LISTENER ||
 +      conn->type == CONN_TYPE_EXT_OR_LISTENER ||
 +      conn->type == CONN_TYPE_AP_LISTENER ||
 +      conn->type == CONN_TYPE_AP_TRANS_LISTENER ||
 +      conn->type == CONN_TYPE_AP_DNS_LISTENER ||
 +      conn->type == CONN_TYPE_AP_NATD_LISTENER ||
 +      conn->type == CONN_TYPE_AP_HTTP_CONNECT_LISTENER ||
 +      conn->type == CONN_TYPE_DIR_LISTENER ||
 +      conn->type == CONN_TYPE_CONTROL_LISTENER)
 +    return 1;
 +  return 0;
 +}
 +
 +/** Return 1 if <b>conn</b> is in state "open" and is not marked
 + * for close, else return 0.
 + */
 +int
 +connection_state_is_open(connection_t *conn)
 +{
 +  tor_assert(conn);
 +
 +  if (conn->marked_for_close)
 +    return 0;
 +
 +  if ((conn->type == CONN_TYPE_OR && conn->state == OR_CONN_STATE_OPEN) ||
 +      (conn->type == CONN_TYPE_EXT_OR) ||
 +      (conn->type == CONN_TYPE_AP && conn->state == AP_CONN_STATE_OPEN) ||
 +      (conn->type == CONN_TYPE_EXIT && conn->state == EXIT_CONN_STATE_OPEN) ||
 +      (conn->type == CONN_TYPE_CONTROL &&
 +       conn->state == CONTROL_CONN_STATE_OPEN))
 +    return 1;
 +
 +  return 0;
 +}
 +
 +/** Return 1 if conn is in 'connecting' state, else return 0. */
 +int
 +connection_state_is_connecting(connection_t *conn)
 +{
 +  tor_assert(conn);
 +
 +  if (conn->marked_for_close)
 +    return 0;
 +  switch (conn->type)
 +    {
 +    case CONN_TYPE_OR:
 +      return conn->state == OR_CONN_STATE_CONNECTING;
 +    case CONN_TYPE_EXIT:
 +      return conn->state == EXIT_CONN_STATE_CONNECTING;
 +    case CONN_TYPE_DIR:
 +      return conn->state == DIR_CONN_STATE_CONNECTING;
 +    }
 +
 +  return 0;
 +}
 +
 +/** Allocates a base64'ed authenticator for use in http or https
 + * auth, based on the input string <b>authenticator</b>. Returns it
 + * if success, else returns NULL. */
 +char *
 +alloc_http_authenticator(const char *authenticator)
 +{
 +  /* an authenticator in Basic authentication
 +   * is just the string "username:password" */
 +  const size_t authenticator_length = strlen(authenticator);
 +  const size_t base64_authenticator_length =
 +      base64_encode_size(authenticator_length, 0) + 1;
 +  char *base64_authenticator = tor_malloc(base64_authenticator_length);
 +  if (base64_encode(base64_authenticator, base64_authenticator_length,
 +                    authenticator, authenticator_length, 0) < 0) {
 +    tor_free(base64_authenticator); /* free and set to null */
 +  }
 +  return base64_authenticator;
 +}
 +
 +/** Given a socket handle, check whether the local address (sockname) of the
 + * socket is one that we've connected from before.  If so, double-check
 + * whether our address has changed and we need to generate keys.  If we do,
 + * call init_keys().
 + */
 +static void
 +client_check_address_changed(tor_socket_t sock)
 +{
 +  tor_addr_t out_addr, iface_addr;
 +  tor_addr_t **last_interface_ip_ptr;
 +  sa_family_t family;
 +
 +  if (!outgoing_addrs)
 +    outgoing_addrs = smartlist_new();
 +
 +  if (tor_addr_from_getsockname(&out_addr, sock) < 0) {
 +    int e = tor_socket_errno(sock);
 +    log_warn(LD_NET, "getsockname() to check for address change failed: %s",
 +             tor_socket_strerror(e));
 +    return;
 +  }
 +  family = tor_addr_family(&out_addr);
 +
 +  if (family == AF_INET)
 +    last_interface_ip_ptr = &last_interface_ipv4;
 +  else if (family == AF_INET6)
 +    last_interface_ip_ptr = &last_interface_ipv6;
 +  else
 +    return;
 +
 +  if (! *last_interface_ip_ptr) {
 +    tor_addr_t *a = tor_malloc_zero(sizeof(tor_addr_t));
 +    if (get_interface_address6(LOG_INFO, family, a)==0) {
 +      *last_interface_ip_ptr = a;
 +    } else {
 +      tor_free(a);
 +    }
 +  }
 +
 +  /* If we've used this address previously, we're okay. */
 +  SMARTLIST_FOREACH(outgoing_addrs, const tor_addr_t *, a_ptr,
 +                    if (tor_addr_eq(a_ptr, &out_addr))
 +                      return;
 +                    );
 +
 +  /* Uh-oh.  We haven't connected from this address before. Has the interface
 +   * address changed? */
 +  if (get_interface_address6(LOG_INFO, family, &iface_addr)<0)
 +    return;
 +
 +  if (tor_addr_eq(&iface_addr, *last_interface_ip_ptr)) {
 +    /* Nope, it hasn't changed.  Add this address to the list. */
 +    smartlist_add(outgoing_addrs, tor_memdup(&out_addr, sizeof(tor_addr_t)));
 +  } else {
 +    /* The interface changed.  We're a client, so we need to regenerate our
 +     * keys.  First, reset the state. */
 +    log_notice(LD_NET, "Our IP address has changed.  Rotating keys...");
 +    tor_addr_copy(*last_interface_ip_ptr, &iface_addr);
 +    SMARTLIST_FOREACH(outgoing_addrs, tor_addr_t*, a_ptr, tor_free(a_ptr));
 +    smartlist_clear(outgoing_addrs);
 +    smartlist_add(outgoing_addrs, tor_memdup(&out_addr, sizeof(tor_addr_t)));
 +    /* We'll need to resolve ourselves again. */
 +    reset_last_resolved_addr();
 +    /* Okay, now change our keys. */
 +    ip_address_changed(1);
 +  }
 +}
 +
 +/** Some systems have limited system buffers for recv and xmit on
 + * sockets allocated in a virtual server or similar environment. For a Tor
 + * server this can produce the "Error creating network socket: No buffer
 + * space available" error once all available TCP buffer space is consumed.
 + * This method will attempt to constrain the buffers allocated for the socket
 + * to the desired size to stay below system TCP buffer limits.
 + */
 +static void
 +set_constrained_socket_buffers(tor_socket_t sock, int size)
 +{
 +  void *sz = (void*)&size;
 +  socklen_t sz_sz = (socklen_t) sizeof(size);
 +  if (setsockopt(sock, SOL_SOCKET, SO_SNDBUF, sz, sz_sz) < 0) {
 +    int e = tor_socket_errno(sock);
 +    log_warn(LD_NET, "setsockopt() to constrain send "
 +             "buffer to %d bytes failed: %s", size, tor_socket_strerror(e));
 +  }
 +  if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF, sz, sz_sz) < 0) {
 +    int e = tor_socket_errno(sock);
 +    log_warn(LD_NET, "setsockopt() to constrain recv "
 +             "buffer to %d bytes failed: %s", size, tor_socket_strerror(e));
 +  }
 +}
 +
 +/** Process new bytes that have arrived on conn-\>inbuf.
 + *
 + * This function just passes conn to the connection-specific
 + * connection_*_process_inbuf() function. It also passes in
 + * package_partial if wanted.
 + */
 +static int
 +connection_process_inbuf(connection_t *conn, int package_partial)
 +{
 +  tor_assert(conn);
 +
 +  switch (conn->type) {
 +    case CONN_TYPE_OR:
 +      return connection_or_process_inbuf(TO_OR_CONN(conn));
 +    case CONN_TYPE_EXT_OR:
 +      return connection_ext_or_process_inbuf(TO_OR_CONN(conn));
 +    case CONN_TYPE_EXIT:
 +    case CONN_TYPE_AP:
 +      return connection_edge_process_inbuf(TO_EDGE_CONN(conn),
 +                                           package_partial);
 +    case CONN_TYPE_DIR:
 +      return connection_dir_process_inbuf(TO_DIR_CONN(conn));
 +    case CONN_TYPE_CONTROL:
 +      return connection_control_process_inbuf(TO_CONTROL_CONN(conn));
 +    default:
 +      log_err(LD_BUG,"got unexpected conn type %d.", conn->type);
 +      tor_fragile_assert();
 +      return -1;
 +  }
 +}
 +
 +/** Called whenever we've written data on a connection. */
 +static int
 +connection_flushed_some(connection_t *conn)
 +{
 +  int r = 0;
 +  tor_assert(!conn->in_flushed_some);
 +  conn->in_flushed_some = 1;
 +  if (conn->type == CONN_TYPE_DIR &&
 +      conn->state == DIR_CONN_STATE_SERVER_WRITING) {
 +    r = connection_dirserv_flushed_some(TO_DIR_CONN(conn));
 +  } else if (conn->type == CONN_TYPE_OR) {
 +    r = connection_or_flushed_some(TO_OR_CONN(conn));
 +  } else if (CONN_IS_EDGE(conn)) {
 +    r = connection_edge_flushed_some(TO_EDGE_CONN(conn));
 +  }
 +  conn->in_flushed_some = 0;
 +  return r;
 +}
 +
 +/** We just finished flushing bytes to the appropriately low network layer,
 + * and there are no more bytes remaining in conn-\>outbuf or
 + * conn-\>tls to be flushed.
 + *
 + * This function just passes conn to the connection-specific
 + * connection_*_finished_flushing() function.
 + */
 +static int
 +connection_finished_flushing(connection_t *conn)
 +{
 +  tor_assert(conn);
 +
 +  /* If the connection is closed, don't try to do anything more here. */
 +  if (CONN_IS_CLOSED(conn))
 +    return 0;
 +
 +//  log_fn(LOG_DEBUG,"entered. Socket %u.", conn->s);
 +
 +  connection_stop_writing(conn);
 +
 +  switch (conn->type) {
 +    case CONN_TYPE_OR:
 +      return connection_or_finished_flushing(TO_OR_CONN(conn));
 +    case CONN_TYPE_EXT_OR:
 +      return connection_ext_or_finished_flushing(TO_OR_CONN(conn));
 +    case CONN_TYPE_AP:
 +    case CONN_TYPE_EXIT:
 +      return connection_edge_finished_flushing(TO_EDGE_CONN(conn));
 +    case CONN_TYPE_DIR:
 +      return connection_dir_finished_flushing(TO_DIR_CONN(conn));
 +    case CONN_TYPE_CONTROL:
 +      return connection_control_finished_flushing(TO_CONTROL_CONN(conn));
 +    default:
 +      log_err(LD_BUG,"got unexpected conn type %d.", conn->type);
 +      tor_fragile_assert();
 +      return -1;
 +  }
 +}
 +
 +/** Called when our attempt to connect() to another server has just
 + * succeeded.
 + *
 + * This function just passes conn to the connection-specific
 + * connection_*_finished_connecting() function.
 + */
 +static int
 +connection_finished_connecting(connection_t *conn)
 +{
 +  tor_assert(conn);
 +
 +  if (!server_mode(get_options())) {
 +    /* See whether getsockname() says our address changed.  We need to do this
 +     * now that the connection has finished, because getsockname() on Windows
 +     * won't work until then. */
 +    client_check_address_changed(conn->s);
 +  }
 +
 +  switch (conn->type)
 +    {
 +    case CONN_TYPE_OR:
 +      return connection_or_finished_connecting(TO_OR_CONN(conn));
 +    case CONN_TYPE_EXIT:
 +      return connection_edge_finished_connecting(TO_EDGE_CONN(conn));
 +    case CONN_TYPE_DIR:
 +      return connection_dir_finished_connecting(TO_DIR_CONN(conn));
 +    default:
 +      log_err(LD_BUG,"got unexpected conn type %d.", conn->type);
 +      tor_fragile_assert();
 +      return -1;
 +  }
 +}
 +
 +/** Callback: invoked when a connection reaches an EOF event. */
 +static int
 +connection_reached_eof(connection_t *conn)
 +{
 +  switch (conn->type) {
 +    case CONN_TYPE_OR:
 +    case CONN_TYPE_EXT_OR:
 +      return connection_or_reached_eof(TO_OR_CONN(conn));
 +    case CONN_TYPE_AP:
 +    case CONN_TYPE_EXIT:
 +      return connection_edge_reached_eof(TO_EDGE_CONN(conn));
 +    case CONN_TYPE_DIR:
 +      return connection_dir_reached_eof(TO_DIR_CONN(conn));
 +    case CONN_TYPE_CONTROL:
 +      return connection_control_reached_eof(TO_CONTROL_CONN(conn));
 +    default:
 +      log_err(LD_BUG,"got unexpected conn type %d.", conn->type);
 +      tor_fragile_assert();
 +      return -1;
 +  }
 +}
 +
 +/** Comparator for the two-orconn case in OOS victim sort */
 +static int
 +oos_victim_comparator_for_orconns(or_connection_t *a, or_connection_t *b)
 +{
 +  int a_circs, b_circs;
 +  /* Fewer circuits == higher priority for OOS kill, sort earlier */
 +
 +  a_circs = connection_or_get_num_circuits(a);
 +  b_circs = connection_or_get_num_circuits(b);
 +
 +  if (a_circs < b_circs) return 1;
 +  else if (a_circs > b_circs) return -1;
 +  else return 0;
 +}
 +
 +/** Sort comparator for OOS victims; better targets sort before worse
 + * ones. */
 +static int
 +oos_victim_comparator(const void **a_v, const void **b_v)
 +{
 +  connection_t *a = NULL, *b = NULL;
 +
 +  /* Get connection pointers out */
 +
 +  a = (connection_t *)(*a_v);
 +  b = (connection_t *)(*b_v);
 +
 +  tor_assert(a != NULL);
 +  tor_assert(b != NULL);
 +
 +  /*
 +   * We always prefer orconns as victims currently; we won't even see
 +   * these non-orconn cases, but if we do, sort them after orconns.
 +   */
 +  if (a->type == CONN_TYPE_OR && b->type == CONN_TYPE_OR) {
 +    return oos_victim_comparator_for_orconns(TO_OR_CONN(a), TO_OR_CONN(b));
 +  } else {
 +    /*
 +     * One isn't an orconn; if one is, it goes first.  We currently have no
 +     * opinions about cases where neither is an orconn.
 +     */
 +    if (a->type == CONN_TYPE_OR) return -1;
 +    else if (b->type == CONN_TYPE_OR) return 1;
 +    else return 0;
 +  }
 +}
 +
 +/** Pick n victim connections for the OOS handler and return them in a
 + * smartlist.
 + */
 +MOCK_IMPL(STATIC smartlist_t *,
 +pick_oos_victims, (int n))
 +{
 +  smartlist_t *eligible = NULL, *victims = NULL;
 +  smartlist_t *conns;
 +  int conn_counts_by_type[CONN_TYPE_MAX_ + 1], i;
 +
 +  /*
 +   * Big damn assumption (someone improve this someday!):
 +   *
 +   * Socket exhaustion normally happens on high-volume relays, and so
 +   * most of the connections involved are orconns.  We should pick victims
 +   * by assembling a list of all orconns, and sorting them in order of
 +   * how much 'damage' by some metric we'd be doing by dropping them.
 +   *
 +   * If we move on from orconns, we should probably think about incoming
 +   * directory connections next, or exit connections.  Things we should
 +   * probably never kill are controller connections and listeners.
 +   *
 +   * This function will count how many connections of different types
 +   * exist and log it for purposes of gathering data on typical OOS
 +   * situations to guide future improvements.
 +   */
 +
 +  /* First, get the connection array */
 +  conns = get_connection_array();
 +  /*
 +   * Iterate it and pick out eligible connection types, and log some stats
 +   * along the way.
 +   */
 +  eligible = smartlist_new();
 +  memset(conn_counts_by_type, 0, sizeof(conn_counts_by_type));
 +  SMARTLIST_FOREACH_BEGIN(conns, connection_t *, c) {
 +    /* Bump the counter */
 +    tor_assert(c->type <= CONN_TYPE_MAX_);
 +    ++(conn_counts_by_type[c->type]);
 +
 +    /* Skip anything without a socket we can free */
 +    if (!(SOCKET_OK(c->s))) {
 +      continue;
 +    }
 +
 +    /* Skip anything we would count as moribund */
 +    if (connection_is_moribund(c)) {
 +      continue;
 +    }
 +
 +    switch (c->type) {
 +      case CONN_TYPE_OR:
 +        /* We've got an orconn, it's eligible to be OOSed */
 +        smartlist_add(eligible, c);
 +        break;
 +      default:
 +        /* We don't know what to do with it, ignore it */
 +        break;
 +    }
 +  } SMARTLIST_FOREACH_END(c);
 +
 +  /* Log some stats */
 +  if (smartlist_len(conns) > 0) {
 +    /* At least one counter must be non-zero */
 +    log_info(LD_NET, "Some stats on conn types seen during OOS follow");
 +    for (i = CONN_TYPE_MIN_; i <= CONN_TYPE_MAX_; ++i) {
 +      /* Did we see any? */
 +      if (conn_counts_by_type[i] > 0) {
 +        log_info(LD_NET, "%s: %d conns",
 +                 conn_type_to_string(i),
 +                 conn_counts_by_type[i]);
 +      }
 +    }
 +    log_info(LD_NET, "Done with OOS conn type stats");
 +  }
 +
 +  /* Did we find more eligible targets than we want to kill? */
 +  if (smartlist_len(eligible) > n) {
 +    /* Sort the list in order of target preference */
 +    smartlist_sort(eligible, oos_victim_comparator);
 +    /* Pick first n as victims */
 +    victims = smartlist_new();
 +    for (i = 0; i < n; ++i) {
 +      smartlist_add(victims, smartlist_get(eligible, i));
 +    }
 +    /* Free the original list */
 +    smartlist_free(eligible);
 +  } else {
 +    /* No, we can just call them all victims */
 +    victims = eligible;
 +  }
 +
 +  return victims;
 +}
 +
 +/** Kill a list of connections for the OOS handler. */
 +MOCK_IMPL(STATIC void,
 +kill_conn_list_for_oos, (smartlist_t *conns))
 +{
 +  if (!conns) return;
 +
 +  SMARTLIST_FOREACH_BEGIN(conns, connection_t *, c) {
 +    /* Make sure the channel layer gets told about orconns */
 +    if (c->type == CONN_TYPE_OR) {
 +      connection_or_close_for_error(TO_OR_CONN(c), 1);
 +    } else {
 +      connection_mark_for_close(c);
 +    }
 +  } SMARTLIST_FOREACH_END(c);
 +
 +  log_notice(LD_NET,
 +             "OOS handler marked %d connections",
 +             smartlist_len(conns));
 +}
 +
 +/** Check if a connection is on the way out so the OOS handler doesn't try
 + * to kill more than it needs. */
 +int
 +connection_is_moribund(connection_t *conn)
 +{
 +  if (conn != NULL &&
 +      (conn->conn_array_index < 0 ||
 +       conn->marked_for_close)) {
 +    return 1;
 +  } else {
 +    return 0;
 +  }
 +}
 +
 +/** Out-of-Sockets handler; n_socks is the current number of open
 + * sockets, and failed is non-zero if a socket exhaustion related
 + * error immediately preceded this call.  This is where to do
 + * circuit-killing heuristics as needed.
 + */
 +void
 +connection_check_oos(int n_socks, int failed)
 +{
 +  int target_n_socks = 0, moribund_socks, socks_to_kill;
 +  smartlist_t *conns;
 +
 +  /* Early exit: is OOS checking disabled? */
 +  if (get_options()->DisableOOSCheck) {
 +    return;
 +  }
 +
 +  /* Sanity-check args */
 +  tor_assert(n_socks >= 0);
 +
 +  /*
 +   * Make some log noise; keep it at debug level since this gets a chance
 +   * to run on every connection attempt.
 +   */
 +  log_debug(LD_NET,
 +            "Running the OOS handler (%d open sockets, %s)",
 +            n_socks, (failed != 0) ? "exhaustion seen" : "no exhaustion");
 +
 +  /*
 +   * Check if we're really handling an OOS condition, and if so decide how
 +   * many sockets we want to get down to.  Be sure we check if the threshold
 +   * is distinct from zero first; it's possible for this to be called a few
 +   * times before we've finished reading the config.
 +   */
 +  if (n_socks >= get_options()->ConnLimit_high_thresh &&
 +      get_options()->ConnLimit_high_thresh != 0 &&
 +      get_options()->ConnLimit_ != 0) {
 +    /* Try to get down to the low threshold */
 +    target_n_socks = get_options()->ConnLimit_low_thresh;
 +    log_notice(LD_NET,
 +               "Current number of sockets %d is greater than configured "
 +               "limit %d; OOS handler trying to get down to %d",
 +               n_socks, get_options()->ConnLimit_high_thresh,
 +               target_n_socks);
 +  } else if (failed) {
 +    /*
 +     * If we're not at the limit but we hit a socket exhaustion error, try to
 +     * drop some (but not as aggressively as ConnLimit_low_threshold, which is
 +     * 3/4 of ConnLimit_)
 +     */
 +    target_n_socks = (n_socks * 9) / 10;
 +    log_notice(LD_NET,
 +               "We saw socket exhaustion at %d open sockets; OOS handler "
 +               "trying to get down to %d",
 +               n_socks, target_n_socks);
 +  }
 +
 +  if (target_n_socks > 0) {
 +    /*
 +     * It's an OOS!
 +     *
 +     * Count moribund sockets; it's be important that anything we decide
 +     * to get rid of here but don't immediately close get counted as moribund
 +     * on subsequent invocations so we don't try to kill too many things if
 +     * connection_check_oos() gets called multiple times.
 +     */
 +    moribund_socks = connection_count_moribund();
 +
 +    if (moribund_socks < n_socks - target_n_socks) {
 +      socks_to_kill = n_socks - target_n_socks - moribund_socks;
 +
 +      conns = pick_oos_victims(socks_to_kill);
 +      if (conns) {
 +        kill_conn_list_for_oos(conns);
 +        log_notice(LD_NET,
 +                   "OOS handler killed %d conns", smartlist_len(conns));
 +        smartlist_free(conns);
 +      } else {
 +        log_notice(LD_NET, "OOS handler failed to pick any victim conns");
 +      }
 +    } else {
 +      log_notice(LD_NET,
 +                 "Not killing any sockets for OOS because there are %d "
 +                 "already moribund, and we only want to eliminate %d",
 +                 moribund_socks, n_socks - target_n_socks);
 +    }
 +  }
 +}
 +
 +/** Log how many bytes are used by buffers of different kinds and sizes. */
 +void
 +connection_dump_buffer_mem_stats(int severity)
 +{
 +  uint64_t used_by_type[CONN_TYPE_MAX_+1];
 +  uint64_t alloc_by_type[CONN_TYPE_MAX_+1];
 +  int n_conns_by_type[CONN_TYPE_MAX_+1];
 +  uint64_t total_alloc = 0;
 +  uint64_t total_used = 0;
 +  int i;
 +  smartlist_t *conns = get_connection_array();
 +
 +  memset(used_by_type, 0, sizeof(used_by_type));
 +  memset(alloc_by_type, 0, sizeof(alloc_by_type));
 +  memset(n_conns_by_type, 0, sizeof(n_conns_by_type));
 +
 +  SMARTLIST_FOREACH_BEGIN(conns, connection_t *, c) {
 +    int tp = c->type;
 +    ++n_conns_by_type[tp];
 +    if (c->inbuf) {
 +      used_by_type[tp] += buf_datalen(c->inbuf);
 +      alloc_by_type[tp] += buf_allocation(c->inbuf);
 +    }
 +    if (c->outbuf) {
 +      used_by_type[tp] += buf_datalen(c->outbuf);
 +      alloc_by_type[tp] += buf_allocation(c->outbuf);
 +    }
 +  } SMARTLIST_FOREACH_END(c);
 +  for (i=0; i <= CONN_TYPE_MAX_; ++i) {
 +    total_used += used_by_type[i];
 +    total_alloc += alloc_by_type[i];
 +  }
 +
 +  tor_log(severity, LD_GENERAL,
 +     "In buffers for %d connections: %"PRIu64" used/%"PRIu64" allocated",
 +      smartlist_len(conns),
 +      (total_used), (total_alloc));
 +  for (i=CONN_TYPE_MIN_; i <= CONN_TYPE_MAX_; ++i) {
 +    if (!n_conns_by_type[i])
 +      continue;
 +    tor_log(severity, LD_GENERAL,
 +        "  For %d %s connections: %"PRIu64" used/%"PRIu64" allocated",
 +        n_conns_by_type[i], conn_type_to_string(i),
 +        (used_by_type[i]), (alloc_by_type[i]));
 +  }
 +}
 +
 +/** Verify that connection <b>conn</b> has all of its invariants
 + * correct. Trigger an assert if anything is invalid.
 + */
 +void
 +assert_connection_ok(connection_t *conn, time_t now)
 +{
 +  (void) now; /* XXXX unused. */
 +  tor_assert(conn);
 +  tor_assert(conn->type >= CONN_TYPE_MIN_);
 +  tor_assert(conn->type <= CONN_TYPE_MAX_);
 +
 +  switch (conn->type) {
 +    case CONN_TYPE_OR:
 +    case CONN_TYPE_EXT_OR:
 +      tor_assert(conn->magic == OR_CONNECTION_MAGIC);
 +      break;
 +    case CONN_TYPE_AP:
 +      tor_assert(conn->magic == ENTRY_CONNECTION_MAGIC);
 +      break;
 +    case CONN_TYPE_EXIT:
 +      tor_assert(conn->magic == EDGE_CONNECTION_MAGIC);
 +      break;
 +    case CONN_TYPE_DIR:
 +      tor_assert(conn->magic == DIR_CONNECTION_MAGIC);
 +      break;
 +    case CONN_TYPE_CONTROL:
 +      tor_assert(conn->magic == CONTROL_CONNECTION_MAGIC);
 +      break;
 +    CASE_ANY_LISTENER_TYPE:
 +      tor_assert(conn->magic == LISTENER_CONNECTION_MAGIC);
 +      break;
 +    default:
 +      tor_assert(conn->magic == BASE_CONNECTION_MAGIC);
 +      break;
 +  }
 +
 +  if (conn->linked_conn) {
 +    tor_assert(conn->linked_conn->linked_conn == conn);
 +    tor_assert(conn->linked);
 +  }
 +  if (conn->linked)
 +    tor_assert(!SOCKET_OK(conn->s));
 +
 +  if (conn->outbuf_flushlen > 0) {
 +    /* With optimistic data, we may have queued data in
 +     * EXIT_CONN_STATE_RESOLVING while the conn is not yet marked to writing.
 +     * */
 +    tor_assert((conn->type == CONN_TYPE_EXIT &&
 +                conn->state == EXIT_CONN_STATE_RESOLVING) ||
 +               connection_is_writing(conn) ||
 +               conn->write_blocked_on_bw ||
 +               (CONN_IS_EDGE(conn) &&
 +                TO_EDGE_CONN(conn)->edge_blocked_on_circ));
 +  }
 +
 +  if (conn->hold_open_until_flushed)
 +    tor_assert(conn->marked_for_close);
 +
 +  /* XXXX check: read_blocked_on_bw, write_blocked_on_bw, s, conn_array_index,
 +   * marked_for_close. */
 +
 +  /* buffers */
 +  if (conn->inbuf)
 +    buf_assert_ok(conn->inbuf);
 +  if (conn->outbuf)
 +    buf_assert_ok(conn->outbuf);
 +
 +  if (conn->type == CONN_TYPE_OR) {
 +    or_connection_t *or_conn = TO_OR_CONN(conn);
 +    if (conn->state == OR_CONN_STATE_OPEN) {
 +      /* tor_assert(conn->bandwidth > 0); */
 +      /* the above isn't necessarily true: if we just did a TLS
 +       * handshake but we didn't recognize the other peer, or it
 +       * gave a bad cert/etc, then we won't have assigned bandwidth,
 +       * yet it will be open. -RD
 +       */
 +//      tor_assert(conn->read_bucket >= 0);
 +    }
 +//    tor_assert(conn->addr && conn->port);
 +    tor_assert(conn->address);
 +    if (conn->state > OR_CONN_STATE_PROXY_HANDSHAKING)
 +      tor_assert(or_conn->tls);
 +  }
 +
 +  if (CONN_IS_EDGE(conn)) {
 +    /* XXX unchecked: package window, deliver window. */
 +    if (conn->type == CONN_TYPE_AP) {
 +      entry_connection_t *entry_conn = TO_ENTRY_CONN(conn);
 +      if (entry_conn->chosen_exit_optional || entry_conn->chosen_exit_retries)
 +        tor_assert(entry_conn->chosen_exit_name);
 +
 +      tor_assert(entry_conn->socks_request);
 +      if (conn->state == AP_CONN_STATE_OPEN) {
 +        tor_assert(entry_conn->socks_request->has_finished);
 +        if (!conn->marked_for_close) {
 +          tor_assert(ENTRY_TO_EDGE_CONN(entry_conn)->cpath_layer);
 +          assert_cpath_layer_ok(ENTRY_TO_EDGE_CONN(entry_conn)->cpath_layer);
 +        }
 +      }
 +    }
 +    if (conn->type == CONN_TYPE_EXIT) {
 +      tor_assert(conn->purpose == EXIT_PURPOSE_CONNECT ||
 +                 conn->purpose == EXIT_PURPOSE_RESOLVE);
 +    }
 +  } else if (conn->type == CONN_TYPE_DIR) {
 +  } else {
 +    /* Purpose is only used for dir and exit types currently */
 +    tor_assert(!conn->purpose);
 +  }
 +
 +  switch (conn->type)
 +    {
 +    CASE_ANY_LISTENER_TYPE:
 +      tor_assert(conn->state == LISTENER_STATE_READY);
 +      break;
 +    case CONN_TYPE_OR:
 +      tor_assert(conn->state >= OR_CONN_STATE_MIN_);
 +      tor_assert(conn->state <= OR_CONN_STATE_MAX_);
 +      break;
 +    case CONN_TYPE_EXT_OR:
 +      tor_assert(conn->state >= EXT_OR_CONN_STATE_MIN_);
 +      tor_assert(conn->state <= EXT_OR_CONN_STATE_MAX_);
 +      break;
 +    case CONN_TYPE_EXIT:
 +      tor_assert(conn->state >= EXIT_CONN_STATE_MIN_);
 +      tor_assert(conn->state <= EXIT_CONN_STATE_MAX_);
 +      tor_assert(conn->purpose >= EXIT_PURPOSE_MIN_);
 +      tor_assert(conn->purpose <= EXIT_PURPOSE_MAX_);
 +      break;
 +    case CONN_TYPE_AP:
 +      tor_assert(conn->state >= AP_CONN_STATE_MIN_);
 +      tor_assert(conn->state <= AP_CONN_STATE_MAX_);
 +      tor_assert(TO_ENTRY_CONN(conn)->socks_request);
 +      break;
 +    case CONN_TYPE_DIR:
 +      tor_assert(conn->state >= DIR_CONN_STATE_MIN_);
 +      tor_assert(conn->state <= DIR_CONN_STATE_MAX_);
 +      tor_assert(conn->purpose >= DIR_PURPOSE_MIN_);
 +      tor_assert(conn->purpose <= DIR_PURPOSE_MAX_);
 +      break;
 +    case CONN_TYPE_CONTROL:
 +      tor_assert(conn->state >= CONTROL_CONN_STATE_MIN_);
 +      tor_assert(conn->state <= CONTROL_CONN_STATE_MAX_);
 +      break;
 +    default:
 +      tor_assert(0);
 +  }
 +}
 +
 +/** Fills <b>addr</b> and <b>port</b> with the details of the global
 + *  proxy server we are using.
 + *  <b>conn</b> contains the connection we are using the proxy for.
 + *
 + *  Return 0 on success, -1 on failure.
 + */
 +int
 +get_proxy_addrport(tor_addr_t *addr, uint16_t *port, int *proxy_type,
 +                   const connection_t *conn)
 +{
 +  const or_options_t *options = get_options();
 +
 +  /* Client Transport Plugins can use another proxy, but that should be hidden
 +   * from the rest of tor (as the plugin is responsible for dealing with the
 +   * proxy), check it first, then check the rest of the proxy types to allow
 +   * the config to have unused ClientTransportPlugin entries.
 +   */
 +  if (options->ClientTransportPlugin) {
 +    const transport_t *transport = NULL;
 +    int r;
 +    r = get_transport_by_bridge_addrport(&conn->addr, conn->port, &transport);
 +    if (r<0)
 +      return -1;
 +    if (transport) { /* transport found */
 +      tor_addr_copy(addr, &transport->addr);
 +      *port = transport->port;
 +      *proxy_type = transport->socks_version;
 +      return 0;
 +    }
 +
 +    /* Unused ClientTransportPlugin. */
 +  }
 +
 +  if (options->HTTPSProxy) {
 +    tor_addr_copy(addr, &options->HTTPSProxyAddr);
 +    *port = options->HTTPSProxyPort;
 +    *proxy_type = PROXY_CONNECT;
 +    return 0;
 +  } else if (options->Socks4Proxy) {
 +    tor_addr_copy(addr, &options->Socks4ProxyAddr);
 +    *port = options->Socks4ProxyPort;
 +    *proxy_type = PROXY_SOCKS4;
 +    return 0;
 +  } else if (options->Socks5Proxy) {
 +    tor_addr_copy(addr, &options->Socks5ProxyAddr);
 +    *port = options->Socks5ProxyPort;
 +    *proxy_type = PROXY_SOCKS5;
 +    return 0;
 +  }
 +
 +  tor_addr_make_unspec(addr);
 +  *port = 0;
 +  *proxy_type = PROXY_NONE;
 +  return 0;
 +}
 +
 +/** Log a failed connection to a proxy server.
 + *  <b>conn</b> is the connection we use the proxy server for. */
 +void
 +log_failed_proxy_connection(connection_t *conn)
 +{
 +  tor_addr_t proxy_addr;
 +  uint16_t proxy_port;
 +  int proxy_type;
 +
 +  if (get_proxy_addrport(&proxy_addr, &proxy_port, &proxy_type, conn) != 0)
 +    return; /* if we have no proxy set up, leave this function. */
 +
 +  log_warn(LD_NET,
 +           "The connection to the %s proxy server at %s just failed. "
 +           "Make sure that the proxy server is up and running.",
 +           proxy_type_to_string(proxy_type),
 +           fmt_addrport(&proxy_addr, proxy_port));
 +}
 +
 +/** Return string representation of <b>proxy_type</b>. */
 +static const char *
 +proxy_type_to_string(int proxy_type)
 +{
 +  switch (proxy_type) {
 +  case PROXY_CONNECT:   return "HTTP";
 +  case PROXY_SOCKS4:    return "SOCKS4";
 +  case PROXY_SOCKS5:    return "SOCKS5";
 +  case PROXY_PLUGGABLE: return "pluggable transports SOCKS";
 +  case PROXY_NONE:      return "NULL";
 +  default:              tor_assert(0);
 +  }
 +  return NULL; /*Unreached*/
 +}
 +
 +/** Call connection_free_minimal() on every connection in our array, and
 + * release all storage held by connection.c.
 + *
 + * Don't do the checks in connection_free(), because they will
 + * fail.
 + */
 +void
 +connection_free_all(void)
 +{
 +  smartlist_t *conns = get_connection_array();
 +
 +  /* We don't want to log any messages to controllers. */
 +  SMARTLIST_FOREACH(conns, connection_t *, conn,
 +    if (conn->type == CONN_TYPE_CONTROL)
 +      TO_CONTROL_CONN(conn)->event_mask = 0);
 +
 +  control_update_global_event_mask();
 +
 +  /* Unlink everything from the identity map. */
 +  connection_or_clear_identity_map();
 +  connection_or_clear_ext_or_id_map();
 +
 +  /* Clear out our list of broken connections */
 +  clear_broken_connection_map(0);
 +
 +  SMARTLIST_FOREACH(conns, connection_t *, conn,
 +                    connection_free_minimal(conn));
 +
 +  if (outgoing_addrs) {
 +    SMARTLIST_FOREACH(outgoing_addrs, tor_addr_t *, addr, tor_free(addr));
 +    smartlist_free(outgoing_addrs);
 +    outgoing_addrs = NULL;
 +  }
 +
 +  tor_free(last_interface_ipv4);
 +  tor_free(last_interface_ipv6);
 +  last_recorded_accounting_at = 0;
 +
 +  mainloop_event_free(reenable_blocked_connections_ev);
 +  reenable_blocked_connections_is_scheduled = 0;
 +  memset(&reenable_blocked_connections_delay, 0, sizeof(struct timeval));
 +}
 +
 +/** Log a warning, and possibly emit a control event, that <b>received</b> came
 + * at a skewed time.  <b>trusted</b> indicates that the <b>source</b> was one
 + * that we had more faith in and therefore the warning level should have higher
 + * severity.
 + */
 +MOCK_IMPL(void,
 +clock_skew_warning, (const connection_t *conn, long apparent_skew, int trusted,
 +                     log_domain_mask_t domain, const char *received,
 +                     const char *source))
 +{
 +  char dbuf[64];
 +  char *ext_source = NULL, *warn = NULL;
 +  format_time_interval(dbuf, sizeof(dbuf), apparent_skew);
 +  if (conn)
 +    tor_asprintf(&ext_source, "%s:%s:%d", source, conn->address, conn->port);
 +  else
 +    ext_source = tor_strdup(source);
 +  log_fn(trusted ? LOG_WARN : LOG_INFO, domain,
 +         "Received %s with skewed time (%s): "
 +         "It seems that our clock is %s by %s, or that theirs is %s%s. "
 +         "Tor requires an accurate clock to work: please check your time, "
 +         "timezone, and date settings.", received, ext_source,
 +         apparent_skew > 0 ? "ahead" : "behind", dbuf,
 +         apparent_skew > 0 ? "behind" : "ahead",
 +         (!conn || trusted) ? "" : ", or they are sending us the wrong time");
 +  if (trusted) {
 +    control_event_general_status(LOG_WARN, "CLOCK_SKEW SKEW=%ld SOURCE=%s",
 +                                 apparent_skew, ext_source);
 +    tor_asprintf(&warn, "Clock skew %ld in %s from %s", apparent_skew,
 +                 received, source);
 +    control_event_bootstrap_problem(warn, "CLOCK_SKEW", conn, 1);
 +  }
 +  tor_free(warn);
 +  tor_free(ext_source);
 +}
diff --cc src/lib/container/buffers.c
index bda424504,000000000..67887f2f3
mode 100644,000000..100644
--- a/src/lib/container/buffers.c
+++ b/src/lib/container/buffers.c
@@@ -1,925 -1,0 +1,932 @@@
 +/* Copyright (c) 2001 Matej Pfajfar.
 + * Copyright (c) 2001-2004, Roger Dingledine.
 + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
 + * Copyright (c) 2007-2019, The Tor Project, Inc. */
 +/* See LICENSE for licensing information */
 +
 +/**
 + * \file buffers.c
 + * \brief Implements a generic buffer interface.
 + *
 + * A buf_t is a (fairly) opaque byte-oriented FIFO that can read to or flush
 + * from memory, sockets, file descriptors, TLS connections, or another buf_t.
 + * Buffers are implemented as linked lists of memory chunks.
 + *
 + * All socket-backed and TLS-based connection_t objects have a pair of
 + * buffers: one for incoming data, and one for outcoming data.  These are fed
 + * and drained from functions in connection.c, trigged by events that are
 + * monitored in main.c.
 + *
 + * This module only handles the buffer implementation itself. To use a buffer
 + * with the network, a compressor, or a TLS connection, see the other buffer_*
 + * modules.
 + **/
 +
 +#define BUFFERS_PRIVATE
 +#include "orconfig.h"
 +#include <stddef.h>
 +#include "lib/container/buffers.h"
 +#include "lib/cc/torint.h"
 +#include "lib/log/log.h"
 +#include "lib/log/util_bug.h"
 +#include "lib/ctime/di_ops.h"
 +#include "lib/malloc/malloc.h"
 +#include "lib/string/printf.h"
 +#include "lib/time/compat_time.h"
 +
 +#ifdef HAVE_UNISTD_H
 +#include <unistd.h>
 +#endif
 +
 +#include <stdlib.h>
 +#include <string.h>
 +
 +//#define PARANOIA
 +
 +#ifdef PARANOIA
 +/** Helper: If PARANOIA is defined, assert that the buffer in local variable
 + * <b>buf</b> is well-formed. */
 +#define check() STMT_BEGIN buf_assert_ok(buf); STMT_END
 +#else
 +#define check() STMT_NIL
 +#endif /* defined(PARANOIA) */
 +
 +/* Implementation notes:
 + *
 + * After flirting with memmove, and dallying with ring-buffers, we're finally
 + * getting up to speed with the 1970s and implementing buffers as a linked
 + * list of small chunks.  Each buffer has such a list; data is removed from
 + * the head of the list, and added at the tail.  The list is singly linked,
 + * and the buffer keeps a pointer to the head and the tail.
 + *
 + * Every chunk, except the tail, contains at least one byte of data.  Data in
 + * each chunk is contiguous.
 + *
 + * When you need to treat the first N characters on a buffer as a contiguous
 + * string, use the buf_pullup function to make them so.  Don't do this more
 + * than necessary.
 + *
 + * The major free Unix kernels have handled buffers like this since, like,
 + * forever.
 + */
 +
 +/* Chunk manipulation functions */
 +
 +#define CHUNK_HEADER_LEN offsetof(chunk_t, mem[0])
 +
 +/* We leave this many NUL bytes at the end of the buffer. */
 +#ifdef DISABLE_MEMORY_SENTINELS
 +#define SENTINEL_LEN 0
 +#else
 +#define SENTINEL_LEN 4
 +#endif
 +
 +/* Header size plus NUL bytes at the end */
 +#define CHUNK_OVERHEAD (CHUNK_HEADER_LEN + SENTINEL_LEN)
 +
 +/** Return the number of bytes needed to allocate a chunk to hold
 + * <b>memlen</b> bytes. */
 +#define CHUNK_ALLOC_SIZE(memlen) (CHUNK_OVERHEAD + (memlen))
 +/** Return the number of usable bytes in a chunk allocated with
 + * malloc(<b>memlen</b>). */
 +#define CHUNK_SIZE_WITH_ALLOC(memlen) ((memlen) - CHUNK_OVERHEAD)
 +
 +#define DEBUG_SENTINEL
 +
 +#if defined(DEBUG_SENTINEL) && !defined(DISABLE_MEMORY_SENTINELS)
 +#define DBG_S(s) s
 +#else
 +#define DBG_S(s) (void)0
 +#endif
 +
 +#ifdef DISABLE_MEMORY_SENTINELS
 +#define CHUNK_SET_SENTINEL(chunk, alloclen) STMT_NIL
 +#else
 +#define CHUNK_SET_SENTINEL(chunk, alloclen) do {                        \
 +    uint8_t *a = (uint8_t*) &(chunk)->mem[(chunk)->memlen];             \
 +    DBG_S(uint8_t *b = &((uint8_t*)(chunk))[(alloclen)-SENTINEL_LEN]);  \
 +    DBG_S(tor_assert(a == b));                                          \
 +    memset(a,0,SENTINEL_LEN);                                           \
 +  } while (0)
 +#endif /* defined(DISABLE_MEMORY_SENTINELS) */
 +
 +/** Move all bytes stored in <b>chunk</b> to the front of <b>chunk</b>->mem,
 + * to free up space at the end. */
 +static inline void
 +chunk_repack(chunk_t *chunk)
 +{
 +  if (chunk->datalen && chunk->data != &chunk->mem[0]) {
 +    memmove(chunk->mem, chunk->data, chunk->datalen);
 +  }
 +  chunk->data = &chunk->mem[0];
 +}
 +
 +/** Keep track of total size of allocated chunks for consistency asserts */
 +static size_t total_bytes_allocated_in_chunks = 0;
 +static void
 +buf_chunk_free_unchecked(chunk_t *chunk)
 +{
 +  if (!chunk)
 +    return;
 +#ifdef DEBUG_CHUNK_ALLOC
 +  tor_assert(CHUNK_ALLOC_SIZE(chunk->memlen) == chunk->DBG_alloc);
 +#endif
 +  tor_assert(total_bytes_allocated_in_chunks >=
 +             CHUNK_ALLOC_SIZE(chunk->memlen));
 +  total_bytes_allocated_in_chunks -= CHUNK_ALLOC_SIZE(chunk->memlen);
 +  tor_free(chunk);
 +}
 +static inline chunk_t *
 +chunk_new_with_alloc_size(size_t alloc)
 +{
 +  chunk_t *ch;
 +  ch = tor_malloc(alloc);
 +  ch->next = NULL;
 +  ch->datalen = 0;
 +#ifdef DEBUG_CHUNK_ALLOC
 +  ch->DBG_alloc = alloc;
 +#endif
 +  ch->memlen = CHUNK_SIZE_WITH_ALLOC(alloc);
 +  total_bytes_allocated_in_chunks += alloc;
 +  ch->data = &ch->mem[0];
 +  CHUNK_SET_SENTINEL(ch, alloc);
 +  return ch;
 +}
 +
 +/** Expand <b>chunk</b> until it can hold <b>sz</b> bytes, and return a
 + * new pointer to <b>chunk</b>.  Old pointers are no longer valid. */
 +static inline chunk_t *
 +chunk_grow(chunk_t *chunk, size_t sz)
 +{
 +  off_t offset;
 +  const size_t memlen_orig = chunk->memlen;
 +  const size_t orig_alloc = CHUNK_ALLOC_SIZE(memlen_orig);
 +  const size_t new_alloc = CHUNK_ALLOC_SIZE(sz);
 +  tor_assert(sz > chunk->memlen);
 +  offset = chunk->data - chunk->mem;
 +  chunk = tor_realloc(chunk, new_alloc);
 +  chunk->memlen = sz;
 +  chunk->data = chunk->mem + offset;
 +#ifdef DEBUG_CHUNK_ALLOC
 +  tor_assert(chunk->DBG_alloc == orig_alloc);
 +  chunk->DBG_alloc = new_alloc;
 +#endif
 +  total_bytes_allocated_in_chunks += new_alloc - orig_alloc;
 +  CHUNK_SET_SENTINEL(chunk, new_alloc);
 +  return chunk;
 +}
 +
 +/** Every chunk should take up at least this many bytes. */
 +#define MIN_CHUNK_ALLOC 256
 +/** No chunk should take up more than this many bytes. */
 +#define MAX_CHUNK_ALLOC 65536
 +
 +/** Return the allocation size we'd like to use to hold <b>target</b>
 + * bytes. */
 +size_t
 +buf_preferred_chunk_size(size_t target)
 +{
 +  tor_assert(target <= SIZE_T_CEILING - CHUNK_OVERHEAD);
 +  if (CHUNK_ALLOC_SIZE(target) >= MAX_CHUNK_ALLOC)
 +    return CHUNK_ALLOC_SIZE(target);
 +  size_t sz = MIN_CHUNK_ALLOC;
 +  while (CHUNK_SIZE_WITH_ALLOC(sz) < target) {
 +    sz <<= 1;
 +  }
 +  return sz;
 +}
 +
 +/** Collapse data from the first N chunks from <b>buf</b> into buf->head,
 + * growing it as necessary, until buf->head has the first <b>bytes</b> bytes
 + * of data from the buffer, or until buf->head has all the data in <b>buf</b>.
 + *
 + * Set *<b>head_out</b> to point to the first byte of available data, and
 + * *<b>len_out</b> to the number of bytes of data available at
 + * *<b>head_out</b>. Note that *<b>len_out</b> may be more or less than
 + * <b>bytes</b>, depending on the number of bytes available.
 + */
 +void
 +buf_pullup(buf_t *buf, size_t bytes, const char **head_out, size_t *len_out)
 +{
 +  chunk_t *dest, *src;
 +  size_t capacity;
 +  if (!buf->head) {
 +    *head_out = NULL;
 +    *len_out = 0;
 +    return;
 +  }
 +
 +  check();
 +  if (buf->datalen < bytes)
 +    bytes = buf->datalen;
 +
 +  capacity = bytes;
 +  if (buf->head->datalen >= bytes) {
 +    *head_out = buf->head->data;
 +    *len_out = buf->head->datalen;
 +    return;
 +  }
 +
 +  if (buf->head->memlen >= capacity) {
 +    /* We don't need to grow the first chunk, but we might need to repack it.*/
 +    size_t needed = capacity - buf->head->datalen;
 +    if (CHUNK_REMAINING_CAPACITY(buf->head) < needed)
 +      chunk_repack(buf->head);
 +    tor_assert(CHUNK_REMAINING_CAPACITY(buf->head) >= needed);
 +  } else {
 +    chunk_t *newhead;
 +    size_t newsize;
 +    /* We need to grow the chunk. */
 +    chunk_repack(buf->head);
 +    newsize = CHUNK_SIZE_WITH_ALLOC(buf_preferred_chunk_size(capacity));
 +    newhead = chunk_grow(buf->head, newsize);
 +    tor_assert(newhead->memlen >= capacity);
 +    if (newhead != buf->head) {
 +      if (buf->tail == buf->head)
 +        buf->tail = newhead;
 +      buf->head = newhead;
 +    }
 +  }
 +
 +  dest = buf->head;
 +  while (dest->datalen < bytes) {
 +    size_t n = bytes - dest->datalen;
 +    src = dest->next;
 +    tor_assert(src);
 +    if (n >= src->datalen) {
 +      memcpy(CHUNK_WRITE_PTR(dest), src->data, src->datalen);
 +      dest->datalen += src->datalen;
 +      dest->next = src->next;
 +      if (buf->tail == src)
 +        buf->tail = dest;
 +      buf_chunk_free_unchecked(src);
 +    } else {
 +      memcpy(CHUNK_WRITE_PTR(dest), src->data, n);
 +      dest->datalen += n;
 +      src->data += n;
 +      src->datalen -= n;
 +      tor_assert(dest->datalen == bytes);
 +    }
 +  }
 +
 +  check();
 +  *head_out = buf->head->data;
 +  *len_out = buf->head->datalen;
 +}
 +
 +#ifdef TOR_UNIT_TESTS
 +/* Write sz bytes from cp into a newly allocated buffer buf.
 + * Returns NULL when passed a NULL cp or zero sz.
 + * Asserts on failure: only for use in unit tests.
 + * buf must be freed using buf_free(). */
 +buf_t *
 +buf_new_with_data(const char *cp, size_t sz)
 +{
 +  /* Validate arguments */
-   if (!cp || sz <= 0) {
++  if (!cp || sz <= 0 || sz >= INT_MAX) {
 +    return NULL;
 +  }
 +
 +  tor_assert(sz < SSIZE_T_CEILING);
 +
 +  /* Allocate a buffer */
 +  buf_t *buf = buf_new_with_capacity(sz);
 +  tor_assert(buf);
 +  buf_assert_ok(buf);
 +  tor_assert(!buf->head);
 +
 +  /* Allocate a chunk that is sz bytes long */
 +  buf->head = chunk_new_with_alloc_size(CHUNK_ALLOC_SIZE(sz));
 +  buf->tail = buf->head;
 +  tor_assert(buf->head);
 +  buf_assert_ok(buf);
 +  tor_assert(buf_allocation(buf) >= sz);
 +
 +  /* Copy the data and size the buffers */
 +  tor_assert(sz <= buf_slack(buf));
 +  tor_assert(sz <= CHUNK_REMAINING_CAPACITY(buf->head));
 +  memcpy(&buf->head->mem[0], cp, sz);
 +  buf->datalen = sz;
 +  buf->head->datalen = sz;
 +  buf->head->data = &buf->head->mem[0];
 +  buf_assert_ok(buf);
 +
 +  /* Make sure everything is large enough */
 +  tor_assert(buf_allocation(buf) >= sz);
 +  tor_assert(buf_allocation(buf) >= buf_datalen(buf) + buf_slack(buf));
 +  /* Does the buffer implementation allocate more than the requested size?
 +   * (for example, by rounding up). If so, these checks will fail. */
 +  tor_assert(buf_datalen(buf) == sz);
 +  tor_assert(buf_slack(buf) == 0);
 +
 +  return buf;
 +}
 +#endif /* defined(TOR_UNIT_TESTS) */
 +
 +/** Remove the first <b>n</b> bytes from buf. */
 +void
 +buf_drain(buf_t *buf, size_t n)
 +{
 +  tor_assert(buf->datalen >= n);
 +  while (n) {
 +    tor_assert(buf->head);
 +    if (buf->head->datalen > n) {
 +      buf->head->datalen -= n;
 +      buf->head->data += n;
 +      buf->datalen -= n;
 +      return;
 +    } else {
 +      chunk_t *victim = buf->head;
 +      n -= victim->datalen;
 +      buf->datalen -= victim->datalen;
 +      buf->head = victim->next;
 +      if (buf->tail == victim)
 +        buf->tail = NULL;
 +      buf_chunk_free_unchecked(victim);
 +    }
 +  }
 +  check();
 +}
 +
 +/** Create and return a new buf with default chunk capacity <b>size</b>.
 + */
 +buf_t *
 +buf_new_with_capacity(size_t size)
 +{
 +  buf_t *b = buf_new();
 +  b->default_chunk_size = buf_preferred_chunk_size(size);
 +  return b;
 +}
 +
 +/** Allocate and return a new buffer with default capacity. */
 +buf_t *
 +buf_new(void)
 +{
 +  buf_t *buf = tor_malloc_zero(sizeof(buf_t));
 +  buf->magic = BUFFER_MAGIC;
 +  buf->default_chunk_size = 4096;
 +  return buf;
 +}
 +
 +size_t
 +buf_get_default_chunk_size(const buf_t *buf)
 +{
 +  return buf->default_chunk_size;
 +}
 +
 +/** Remove all data from <b>buf</b>. */
 +void
 +buf_clear(buf_t *buf)
 +{
 +  chunk_t *chunk, *next;
 +  buf->datalen = 0;
 +  for (chunk = buf->head; chunk; chunk = next) {
 +    next = chunk->next;
 +    buf_chunk_free_unchecked(chunk);
 +  }
 +  buf->head = buf->tail = NULL;
 +}
 +
 +/** Return the number of bytes stored in <b>buf</b> */
 +MOCK_IMPL(size_t,
 +buf_datalen, (const buf_t *buf))
 +{
 +  return buf->datalen;
 +}
 +
 +/** Return the total length of all chunks used in <b>buf</b>. */
 +size_t
 +buf_allocation(const buf_t *buf)
 +{
 +  size_t total = 0;
 +  const chunk_t *chunk;
 +  for (chunk = buf->head; chunk; chunk = chunk->next) {
 +    total += CHUNK_ALLOC_SIZE(chunk->memlen);
 +  }
 +  return total;
 +}
 +
 +/** Return the number of bytes that can be added to <b>buf</b> without
 + * performing any additional allocation. */
 +size_t
 +buf_slack(const buf_t *buf)
 +{
 +  if (!buf->tail)
 +    return 0;
 +  else
 +    return CHUNK_REMAINING_CAPACITY(buf->tail);
 +}
 +
 +/** Release storage held by <b>buf</b>. */
 +void
 +buf_free_(buf_t *buf)
 +{
 +  if (!buf)
 +    return;
 +
 +  buf_clear(buf);
 +  buf->magic = 0xdeadbeef;
 +  tor_free(buf);
 +}
 +
 +/** Return a new copy of <b>in_chunk</b> */
 +static chunk_t *
 +chunk_copy(const chunk_t *in_chunk)
 +{
 +  chunk_t *newch = tor_memdup(in_chunk, CHUNK_ALLOC_SIZE(in_chunk->memlen));
 +  total_bytes_allocated_in_chunks += CHUNK_ALLOC_SIZE(in_chunk->memlen);
 +#ifdef DEBUG_CHUNK_ALLOC
 +  newch->DBG_alloc = CHUNK_ALLOC_SIZE(in_chunk->memlen);
 +#endif
 +  newch->next = NULL;
 +  if (in_chunk->data) {
 +    off_t offset = in_chunk->data - in_chunk->mem;
 +    newch->data = newch->mem + offset;
 +  }
 +  return newch;
 +}
 +
 +/** Return a new copy of <b>buf</b> */
 +buf_t *
 +buf_copy(const buf_t *buf)
 +{
 +  chunk_t *ch;
 +  buf_t *out = buf_new();
 +  out->default_chunk_size = buf->default_chunk_size;
 +  for (ch = buf->head; ch; ch = ch->next) {
 +    chunk_t *newch = chunk_copy(ch);
 +    if (out->tail) {
 +      out->tail->next = newch;
 +      out->tail = newch;
 +    } else {
 +      out->head = out->tail = newch;
 +    }
 +  }
 +  out->datalen = buf->datalen;
 +  return out;
 +}
 +
 +/** Append a new chunk with enough capacity to hold <b>capacity</b> bytes to
 + * the tail of <b>buf</b>.  If <b>capped</b>, don't allocate a chunk bigger
 + * than MAX_CHUNK_ALLOC. */
 +chunk_t *
 +buf_add_chunk_with_capacity(buf_t *buf, size_t capacity, int capped)
 +{
 +  chunk_t *chunk;
 +
 +  if (CHUNK_ALLOC_SIZE(capacity) < buf->default_chunk_size) {
 +    chunk = chunk_new_with_alloc_size(buf->default_chunk_size);
 +  } else if (capped && CHUNK_ALLOC_SIZE(capacity) > MAX_CHUNK_ALLOC) {
 +    chunk = chunk_new_with_alloc_size(MAX_CHUNK_ALLOC);
 +  } else {
 +    chunk = chunk_new_with_alloc_size(buf_preferred_chunk_size(capacity));
 +  }
 +
 +  chunk->inserted_time = monotime_coarse_get_stamp();
 +
 +  if (buf->tail) {
 +    tor_assert(buf->head);
 +    buf->tail->next = chunk;
 +    buf->tail = chunk;
 +  } else {
 +    tor_assert(!buf->head);
 +    buf->head = buf->tail = chunk;
 +  }
 +  check();
 +  return chunk;
 +}
 +
 +/** Return the age of the oldest chunk in the buffer <b>buf</b>, in
 + * timestamp units.  Requires the current monotonic timestamp as its
 + * input <b>now</b>.
 + */
 +uint32_t
 +buf_get_oldest_chunk_timestamp(const buf_t *buf, uint32_t now)
 +{
 +  if (buf->head) {
 +    return now - buf->head->inserted_time;
 +  } else {
 +    return 0;
 +  }
 +}
 +
 +size_t
 +buf_get_total_allocation(void)
 +{
 +  return total_bytes_allocated_in_chunks;
 +}
 +
 +/** Append <b>string_len</b> bytes from <b>string</b> to the end of
 + * <b>buf</b>.
 + *
 + * Return the new length of the buffer on success, -1 on failure.
 + */
 +int
 +buf_add(buf_t *buf, const char *string, size_t string_len)
 +{
 +  if (!string_len)
 +    return (int)buf->datalen;
 +  check();
 +
 +  if (BUG(buf->datalen >= INT_MAX))
 +    return -1;
 +  if (BUG(buf->datalen >= INT_MAX - string_len))
 +    return -1;
 +
 +  while (string_len) {
 +    size_t copy;
 +    if (!buf->tail || !CHUNK_REMAINING_CAPACITY(buf->tail))
 +      buf_add_chunk_with_capacity(buf, string_len, 1);
 +
 +    copy = CHUNK_REMAINING_CAPACITY(buf->tail);
 +    if (copy > string_len)
 +      copy = string_len;
 +    memcpy(CHUNK_WRITE_PTR(buf->tail), string, copy);
 +    string_len -= copy;
 +    string += copy;
 +    buf->datalen += copy;
 +    buf->tail->datalen += copy;
 +  }
 +
 +  check();
 +  tor_assert(buf->datalen < INT_MAX);
 +  return (int)buf->datalen;
 +}
 +
 +/** Add a nul-terminated <b>string</b> to <b>buf</b>, not including the
 + * terminating NUL. */
 +void
 +buf_add_string(buf_t *buf, const char *string)
 +{
 +  buf_add(buf, string, strlen(string));
 +}
 +
 +/** As tor_snprintf, but write the results into a buf_t */
 +void
 +buf_add_printf(buf_t *buf, const char *format, ...)
 +{
 +  va_list ap;
 +  va_start(ap,format);
 +  buf_add_vprintf(buf, format, ap);
 +  va_end(ap);
 +}
 +
 +/** As tor_vsnprintf, but write the results into a buf_t. */
 +void
 +buf_add_vprintf(buf_t *buf, const char *format, va_list args)
 +{
 +  /* XXXX Faster implementations are easy enough, but let's optimize later */
 +  char *tmp;
 +  tor_vasprintf(&tmp, format, args);
 +  buf_add(buf, tmp, strlen(tmp));
 +  tor_free(tmp);
 +}
 +
 +/** Return a heap-allocated string containing the contents of <b>buf</b>, plus
 + * a NUL byte. If <b>sz_out</b> is provided, set *<b>sz_out</b> to the length
 + * of the returned string, not including the terminating NUL. */
 +char *
 +buf_extract(buf_t *buf, size_t *sz_out)
 +{
 +  tor_assert(buf);
 +
 +  size_t sz = buf_datalen(buf);
 +  char *result;
 +  result = tor_malloc(sz+1);
 +  buf_peek(buf, result, sz);
 +  result[sz] = 0;
 +  if (sz_out)
 +    *sz_out = sz;
 +  return result;
 +}
 +
 +/** Helper: copy the first <b>string_len</b> bytes from <b>buf</b>
 + * onto <b>string</b>.
 + */
 +void
 +buf_peek(const buf_t *buf, char *string, size_t string_len)
 +{
 +  chunk_t *chunk;
 +
 +  tor_assert(string);
 +  /* make sure we don't ask for too much */
 +  tor_assert(string_len <= buf->datalen);
 +  /* buf_assert_ok(buf); */
 +
 +  chunk = buf->head;
 +  while (string_len) {
 +    size_t copy = string_len;
 +    tor_assert(chunk);
 +    if (chunk->datalen < copy)
 +      copy = chunk->datalen;
 +    memcpy(string, chunk->data, copy);
 +    string_len -= copy;
 +    string += copy;
 +    chunk = chunk->next;
 +  }
 +}
 +
 +/** Remove <b>string_len</b> bytes from the front of <b>buf</b>, and store
 + * them into <b>string</b>.  Return the new buffer size.  <b>string_len</b>
 + * must be \<= the number of bytes on the buffer.
 + */
 +int
 +buf_get_bytes(buf_t *buf, char *string, size_t string_len)
 +{
 +  /* There must be string_len bytes in buf; write them onto string,
 +   * then memmove buf back (that is, remove them from buf).
 +   *
 +   * Return the number of bytes still on the buffer. */
 +
 +  check();
 +  buf_peek(buf, string, string_len);
 +  buf_drain(buf, string_len);
 +  check();
 +  tor_assert(buf->datalen < INT_MAX);
 +  return (int)buf->datalen;
 +}
 +
 +/** Move up to *<b>buf_flushlen</b> bytes from <b>buf_in</b> to
 + * <b>buf_out</b>, and modify *<b>buf_flushlen</b> appropriately.
 + * Return the number of bytes actually copied.
 + */
 +int
 +buf_move_to_buf(buf_t *buf_out, buf_t *buf_in, size_t *buf_flushlen)
 +{
 +  /* We can do way better here, but this doesn't turn up in any profiles. */
 +  char b[4096];
 +  size_t cp, len;
 +
-   if (BUG(buf_out->datalen >= INT_MAX))
++  if (BUG(buf_out->datalen >= INT_MAX || *buf_flushlen >= INT_MAX))
 +    return -1;
 +  if (BUG(buf_out->datalen >= INT_MAX - *buf_flushlen))
 +    return -1;
 +
 +  len = *buf_flushlen;
 +  if (len > buf_in->datalen)
 +    len = buf_in->datalen;
 +
 +  cp = len; /* Remember the number of bytes we intend to copy. */
 +  tor_assert(cp < INT_MAX);
 +  while (len) {
 +    /* This isn't the most efficient implementation one could imagine, since
 +     * it does two copies instead of 1, but I kinda doubt that this will be
 +     * critical path. */
 +    size_t n = len > sizeof(b) ? sizeof(b) : len;
 +    buf_get_bytes(buf_in, b, n);
 +    buf_add(buf_out, b, n);
 +    len -= n;
 +  }
 +  *buf_flushlen -= cp;
 +  return (int)cp;
 +}
 +
 +/** Moves all data from <b>buf_in</b> to <b>buf_out</b>, without copying.
 + */
 +void
 +buf_move_all(buf_t *buf_out, buf_t *buf_in)
 +{
 +  tor_assert(buf_out);
 +  if (!buf_in)
 +    return;
++  if (BUG(buf_out->datalen >= INT_MAX || buf_in->datalen >= INT_MAX))
++    return;
++  if (BUG(buf_out->datalen >= INT_MAX - buf_in->datalen))
++    return;
 +
 +  if (buf_out->head == NULL) {
 +    buf_out->head = buf_in->head;
 +    buf_out->tail = buf_in->tail;
 +  } else {
 +    buf_out->tail->next = buf_in->head;
 +    buf_out->tail = buf_in->tail;
 +  }
 +
 +  buf_out->datalen += buf_in->datalen;
 +  buf_in->head = buf_in->tail = NULL;
 +  buf_in->datalen = 0;
 +}
 +
 +/** Internal structure: represents a position in a buffer. */
 +typedef struct buf_pos_t {
 +  const chunk_t *chunk; /**< Which chunk are we pointing to? */
 +  int pos;/**< Which character inside the chunk's data are we pointing to? */
 +  size_t chunk_pos; /**< Total length of all previous chunks. */
 +} buf_pos_t;
 +
 +/** Initialize <b>out</b> to point to the first character of <b>buf</b>.*/
 +static void
 +buf_pos_init(const buf_t *buf, buf_pos_t *out)
 +{
 +  out->chunk = buf->head;
 +  out->pos = 0;
 +  out->chunk_pos = 0;
 +}
 +
 +/** Advance <b>out</b> to the first appearance of <b>ch</b> at the current
 + * position of <b>out</b>, or later.  Return -1 if no instances are found;
 + * otherwise returns the absolute position of the character. */
 +static off_t
 +buf_find_pos_of_char(char ch, buf_pos_t *out)
 +{
 +  const chunk_t *chunk;
 +  int pos;
 +  tor_assert(out);
 +  if (out->chunk) {
 +    if (out->chunk->datalen) {
 +      tor_assert(out->pos < (off_t)out->chunk->datalen);
 +    } else {
 +      tor_assert(out->pos == 0);
 +    }
 +  }
 +  pos = out->pos;
 +  for (chunk = out->chunk; chunk; chunk = chunk->next) {
 +    char *cp = memchr(chunk->data+pos, ch, chunk->datalen - pos);
 +    if (cp) {
 +      out->chunk = chunk;
 +      tor_assert(cp - chunk->data < INT_MAX);
 +      out->pos = (int)(cp - chunk->data);
 +      return out->chunk_pos + out->pos;
 +    } else {
 +      out->chunk_pos += chunk->datalen;
 +      pos = 0;
 +    }
 +  }
 +  return -1;
 +}
 +
 +/** Advance <b>pos</b> by a single character, if there are any more characters
 + * in the buffer.  Returns 0 on success, -1 on failure. */
 +static inline int
 +buf_pos_inc(buf_pos_t *pos)
 +{
++  tor_assert(pos->pos < INT_MAX - 1);
 +  ++pos->pos;
 +  if (pos->pos == (off_t)pos->chunk->datalen) {
 +    if (!pos->chunk->next)
 +      return -1;
 +    pos->chunk_pos += pos->chunk->datalen;
 +    pos->chunk = pos->chunk->next;
 +    pos->pos = 0;
 +  }
 +  return 0;
 +}
 +
 +/** Return true iff the <b>n</b>-character string in <b>s</b> appears
 + * (verbatim) at <b>pos</b>. */
 +static int
 +buf_matches_at_pos(const buf_pos_t *pos, const char *s, size_t n)
 +{
 +  buf_pos_t p;
 +  if (!n)
 +    return 1;
 +
 +  memcpy(&p, pos, sizeof(p));
 +
 +  while (1) {
 +    char ch = p.chunk->data[p.pos];
 +    if (ch != *s)
 +      return 0;
 +    ++s;
 +    /* If we're out of characters that don't match, we match.  Check this
 +     * _before_ we test incrementing pos, in case we're at the end of the
 +     * string. */
 +    if (--n == 0)
 +      return 1;
 +    if (buf_pos_inc(&p)<0)
 +      return 0;
 +  }
 +}
 +
 +/** Return the first position in <b>buf</b> at which the <b>n</b>-character
 + * string <b>s</b> occurs, or -1 if it does not occur. */
 +int
 +buf_find_string_offset(const buf_t *buf, const char *s, size_t n)
 +{
 +  buf_pos_t pos;
 +  buf_pos_init(buf, &pos);
 +  while (buf_find_pos_of_char(*s, &pos) >= 0) {
 +    if (buf_matches_at_pos(&pos, s, n)) {
 +      tor_assert(pos.chunk_pos + pos.pos < INT_MAX);
 +      return (int)(pos.chunk_pos + pos.pos);
 +    } else {
 +      if (buf_pos_inc(&pos)<0)
 +        return -1;
 +    }
 +  }
 +  return -1;
 +}
 +
 +/** Return 1 iff <b>buf</b> starts with <b>cmd</b>. <b>cmd</b> must be a null
 + * terminated string, of no more than PEEK_BUF_STARTSWITH_MAX bytes. */
 +int
 +buf_peek_startswith(const buf_t *buf, const char *cmd)
 +{
 +  char tmp[PEEK_BUF_STARTSWITH_MAX];
 +  size_t clen = strlen(cmd);
 +  if (clen == 0)
 +    return 1;
 +  if (BUG(clen > sizeof(tmp)))
 +    return 0;
 +  if (buf->datalen < clen)
 +    return 0;
 +  buf_peek(buf, tmp, clen);
 +  return fast_memeq(tmp, cmd, clen);
 +}
 +
 +/** Return the index within <b>buf</b> at which <b>ch</b> first appears,
 + * or -1 if <b>ch</b> does not appear on buf. */
 +static off_t
 +buf_find_offset_of_char(buf_t *buf, char ch)
 +{
 +  chunk_t *chunk;
 +  off_t offset = 0;
++  tor_assert(buf->datalen < INT_MAX);
 +  for (chunk = buf->head; chunk; chunk = chunk->next) {
 +    char *cp = memchr(chunk->data, ch, chunk->datalen);
 +    if (cp)
 +      return offset + (cp - chunk->data);
 +    else
 +      offset += chunk->datalen;
 +  }
 +  return -1;
 +}
 +
 +/** Try to read a single LF-terminated line from <b>buf</b>, and write it
 + * (including the LF), NUL-terminated, into the *<b>data_len</b> byte buffer
 + * at <b>data_out</b>.  Set *<b>data_len</b> to the number of bytes in the
 + * line, not counting the terminating NUL.  Return 1 if we read a whole line,
 + * return 0 if we don't have a whole line yet, and return -1 if the line
 + * length exceeds *<b>data_len</b>.
 + */
 +int
 +buf_get_line(buf_t *buf, char *data_out, size_t *data_len)
 +{
 +  size_t sz;
 +  off_t offset;
 +
 +  if (!buf->head)
 +    return 0;
 +
 +  offset = buf_find_offset_of_char(buf, '\n');
 +  if (offset < 0)
 +    return 0;
 +  sz = (size_t) offset;
 +  if (sz+2 > *data_len) {
 +    *data_len = sz + 2;
 +    return -1;
 +  }
 +  buf_get_bytes(buf, data_out, sz+1);
 +  data_out[sz+1] = '\0';
 +  *data_len = sz+1;
 +  return 1;
 +}
 +
 +/** Set *<b>output</b> to contain a copy of the data in *<b>input</b> */
 +int
 +buf_set_to_copy(buf_t **output,
 +                const buf_t *input)
 +{
 +  if (*output)
 +    buf_free(*output);
 +  *output = buf_copy(input);
 +  return 0;
 +}
 +
 +/** Log an error and exit if <b>buf</b> is corrupted.
 + */
 +void
 +buf_assert_ok(buf_t *buf)
 +{
 +  tor_assert(buf);
 +  tor_assert(buf->magic == BUFFER_MAGIC);
 +
 +  if (! buf->head) {
 +    tor_assert(!buf->tail);
 +    tor_assert(buf->datalen == 0);
 +  } else {
 +    chunk_t *ch;
 +    size_t total = 0;
 +    tor_assert(buf->tail);
 +    for (ch = buf->head; ch; ch = ch->next) {
 +      total += ch->datalen;
 +      tor_assert(ch->datalen <= ch->memlen);
++      tor_assert(ch->datalen < INT_MAX);
 +      tor_assert(ch->data >= &ch->mem[0]);
 +      tor_assert(ch->data <= &ch->mem[0]+ch->memlen);
 +      if (ch->data == &ch->mem[0]+ch->memlen) {
 +        /* LCOV_EXCL_START */
 +        static int warned = 0;
 +        if (! warned) {
 +          log_warn(LD_BUG, "Invariant violation in buf.c related to #15083");
 +          warned = 1;
 +        }
 +        /* LCOV_EXCL_STOP */
 +      }
 +      tor_assert(ch->data+ch->datalen <= &ch->mem[0] + ch->memlen);
 +      if (!ch->next)
 +        tor_assert(ch == buf->tail);
 +    }
 +    tor_assert(buf->datalen == total);
 +  }
 +}



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