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[or-cvs] r10842: Initial "constrained socket buffers" patch from coderman. ne (in tor/trunk: . doc src/or)
Author: nickm
Date: 2007-07-16 12:23:34 -0400 (Mon, 16 Jul 2007)
New Revision: 10842
Added:
tor/trunk/doc/
tor/trunk/src/
Removed:
tor/trunk/doc/
tor/trunk/src/
Modified:
tor/trunk/
tor/trunk/doc/tor.1.in
tor/trunk/src/or/config.c
tor/trunk/src/or/connection.c
tor/trunk/src/or/or.h
Log:
r13773@catbus: nickm | 2007-07-16 11:58:25 -0400
Initial "constrained socket buffers" patch from coderman. needs tweaking.
Property changes on: tor/trunk
___________________________________________________________________
svk:merge ticket from /tor/trunk [r13773] on 8246c3cf-6607-4228-993b-4d95d33730f1
Copied: tor/trunk/doc (from rev 10826, tor/trunk/doc)
Modified: tor/trunk/doc/tor.1.in
===================================================================
--- tor/trunk/doc/tor.1.in 2007-07-14 02:32:19 UTC (rev 10826)
+++ tor/trunk/doc/tor.1.in 2007-07-16 16:23:34 UTC (rev 10842)
@@ -101,6 +101,33 @@
Windows since that platform lacks getrlimit(). (Default: 1000)
.LP
.TP
+\fBConstrainedSockets \fR\fB0\fR|\fB1\fR\fP
+If set, Tor will attempt to shrink the recv and xmit buffers for all
+sockets to the size specified in \fBConstrainedSockSize\fP. This is useful
+for virtual servers and other environments where system level TCP
+buffers may be limited. If you encounter the "Error creating network
+socket: No buffer space available" message you are likely experiencing
+this problem.
+
+The preferred solution is to have the admin increase the buffer pool for
+the host itself via /proc/sys/net/ipv4/tcp_mem or equivalent facility.
+
+The DirPort option should also not be used if TCP buffers are scarce. The
+cached directory requests consume additional sockets which exacerbates the
+problem.
+
+You should \fBnot\fP enable this feature unless you encounter the no buffer
+space available issue. Reducing the TCP buffers affects window size for
+for the TCP stream and will reduce throughput in proportion to round trip
+time on long paths.
+.LP
+.TP
+\fBConstrainedSockSize \fR\fINUM\fP
+When \fBConstrainedSockets\fP is enabled the recv and xmit buffers for
+all sockets will be set to this limit. Must be a value between 2048
+and 262144 in 1024 byte increments. Default of 8192 is recommended.
+.LP
+.TP
\fBControlPort \fR\fIPort\fP
If set, Tor will accept connections on this port and allow those
connections to control the Tor process using the Tor Control Protocol
Copied: tor/trunk/src (from rev 10837, tor/trunk/src)
Modified: tor/trunk/src/or/config.c
===================================================================
--- tor/trunk/src/or/config.c 2007-07-16 04:33:47 UTC (rev 10837)
+++ tor/trunk/src/or/config.c 2007-07-16 16:23:34 UTC (rev 10842)
@@ -146,6 +146,8 @@
VAR("CircuitIdleTimeout", INTERVAL, CircuitIdleTimeout, "1 hour"),
VAR("ClientOnly", BOOL, ClientOnly, "0"),
VAR("ConnLimit", UINT, ConnLimit, "1000"),
+ VAR("ConstrainedSockets", BOOL, ConstrainedSockets, "0"),
+ VAR("ConstrainedSockSize", UINT, ConstrainedSockSize, "8192"),
VAR("ContactInfo", STRING, ContactInfo, NULL),
VAR("ControlListenAddress",LINELIST, ControlListenAddress, NULL),
VAR("ControlPort", UINT, ControlPort, "0"),
@@ -330,6 +332,11 @@
{ "BandwidthBurst", "Limit the maximum token buffer size (also known as "
"burst) to the given number of bytes." },
{ "ConnLimit", "Maximum number of simultaneous sockets allowed." },
+ { "ConstrainedSockets", "Shrink tx and rx buffers for sockets to avoid "
+ "system limits on vservers and related environments. See man page for "
+ "more information regarding this option." },
+ { "ConstrainedSockSize", "Limit socket buffers to this size when "
+ "ConstrainedSockets is enabled." },
/* ControlListenAddress */
{ "ControlPort", "If set, Tor will accept connections from the same machine "
"(localhost only) on this port, and allow those connections to control "
@@ -2925,6 +2932,29 @@
}
}
+ if (options->ConstrainedSockets) {
+ /* If the user wants to constrain socket buffer use, make sure the desired
+ * limit is between MIN|MAX_TCPSOCK_BUFFER in k increments. */
+ if (options->ConstrainedSockSize < MIN_TCPSOCK_BUFFER ||
+ options->ConstrainedSockSize > MAX_TCPSOCK_BUFFER ||
+ options->ConstrainedSockSize % 1024 ) {
+ r = tor_snprintf(buf, sizeof(buf),
+ "ConstrainedSockSize is invalid. Must be a value between %d and %d "
+ "in 1024 byte increments.",
+ MIN_TCPSOCK_BUFFER, MAX_TCPSOCK_BUFFER);
+ *msg = tor_strdup(r >= 0 ? buf : "internal error");
+ return -1;
+ }
+ if (options->DirPort) {
+ /* Providing cached directory entries while system TCP buffers are scarce
+ * will exacerbate the socket errors. Suggest that this be disabled. */
+ COMPLAIN("You have requested constrained socket buffers while also "
+ "serving directory entries via DirPort. It is strongly "
+ "suggested that you disable serving directory requests when "
+ "system TCP buffer resources are scarce.");
+ }
+ }
+
if (rend_config_services(options, 1) < 0)
REJECT("Failed to configure rendezvous options. See logs for details.");
Modified: tor/trunk/src/or/connection.c
===================================================================
--- tor/trunk/src/or/connection.c 2007-07-16 04:33:47 UTC (rev 10837)
+++ tor/trunk/src/or/connection.c 2007-07-16 16:23:34 UTC (rev 10842)
@@ -28,6 +28,7 @@
static int connection_read_to_buf(connection_t *conn, int *max_to_read);
static int connection_process_inbuf(connection_t *conn, int package_partial);
static void client_check_address_changed(int sock);
+static void set_constrained_socket_buffers(int sock, int size);
static uint32_t last_interface_ip = 0;
static smartlist_t *outgoing_addrs = NULL;
@@ -898,6 +899,8 @@
/* length of the remote address. Must be whatever accept() needs. */
socklen_t remotelen = 256;
char tmpbuf[INET_NTOA_BUF_LEN];
+ or_options_t *options = get_options();
+
tor_assert((size_t)remotelen >= sizeof(struct sockaddr_in));
memset(addrbuf, 0, sizeof(addrbuf));
@@ -923,6 +926,10 @@
set_socket_nonblocking(news);
+ if (options->ConstrainedSockets) {
+ set_constrained_socket_buffers (news, options->ConstrainedSockSize);
+ }
+
tor_assert(((struct sockaddr*)addrbuf)->sa_family == conn->socket_family);
if (conn->socket_family == AF_INET) {
@@ -1096,6 +1103,10 @@
set_socket_nonblocking(s);
+ if (options->ConstrainedSockets) {
+ set_constrained_socket_buffers (s, options->ConstrainedSockSize);
+ }
+
memset(&dest_addr,0,sizeof(dest_addr));
dest_addr.sin_family = AF_INET;
dest_addr.sin_port = htons(port);
@@ -2540,6 +2551,29 @@
}
}
+/** 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(int sock, int size)
+{
+ if (setsockopt(sock, SOL_SOCKET, SO_SNDBUF, (const char *)&size, sizeof(size)) < 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, (const char *)&size, sizeof(size)) < 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));
+ }
+ return;
+}
+
/** Process new bytes that have arrived on conn-\>inbuf.
*
* This function just passes conn to the connection-specific
Modified: tor/trunk/src/or/or.h
===================================================================
--- tor/trunk/src/or/or.h 2007-07-16 04:33:47 UTC (rev 10837)
+++ tor/trunk/src/or/or.h 2007-07-16 16:23:34 UTC (rev 10842)
@@ -1748,6 +1748,10 @@
unsigned is_redirect:1;
} exit_redirect_t;
+/* limits for TCP send and recv buffer size used for constrained sockets */
+#define MIN_TCPSOCK_BUFFER 2048
+#define MAX_TCPSOCK_BUFFER 262144 /* 256k */
+
/** A linked list of lines in a config file. */
typedef struct config_line_t {
char *key;
@@ -1889,6 +1893,9 @@
config_line_t *ReachableORAddresses; /**< IP:ports for OR conns. */
config_line_t *ReachableDirAddresses; /**< IP:ports for Dir conns. */
+ int ConstrainedSockets; /**< Shrink xmit and recv socket buffers. */
+ int ConstrainedSockSize; /**< Size of constrained buffers. */
+
/** Application ports that require all nodes in circ to have sufficient
* uptime. */
smartlist_t *LongLivedPorts;