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[or-cvs] r9932: Simplify dns_resolve: use a helper function so that we handl (in tor/trunk: . src/or)
- To: or-cvs@xxxxxxxxxxxxx
- Subject: [or-cvs] r9932: Simplify dns_resolve: use a helper function so that we handl (in tor/trunk: . src/or)
- From: nickm@xxxxxxxx
- Date: Mon, 9 Apr 2007 17:34:14 -0400 (EDT)
- Delivered-to: archiver@seul.org
- Delivered-to: or-cvs-outgoing@seul.org
- Delivered-to: or-cvs@seul.org
- Delivery-date: Mon, 09 Apr 2007 17:34:21 -0400
- Reply-to: or-talk@xxxxxxxxxxxxx
- Sender: owner-or-cvs@xxxxxxxxxxxxx
Author: nickm
Date: 2007-04-09 17:34:13 -0400 (Mon, 09 Apr 2007)
New Revision: 9932
Modified:
tor/trunk/
tor/trunk/src/or/dns.c
Log:
r12688@Kushana: nickm | 2007-04-09 17:29:12 -0400
Simplify dns_resolve: use a helper function so that we handle the error/answer/pending cases uniformly in dns_resolve, and everything else in dns_resolve_impl.
Property changes on: tor/trunk
___________________________________________________________________
svk:merge ticket from /tor/trunk [r12688] on c95137ef-5f19-0410-b913-86e773d04f59
Modified: tor/trunk/src/or/dns.c
===================================================================
--- tor/trunk/src/or/dns.c 2007-04-09 21:34:03 UTC (rev 9931)
+++ tor/trunk/src/or/dns.c 2007-04-09 21:34:13 UTC (rev 9932)
@@ -97,6 +97,8 @@
static void add_wildcarded_test_address(const char *address);
static int configure_nameservers(int force);
static int answer_is_wildcarded(const char *ip);
+static int dns_resolve_impl(edge_connection_t *exitconn, int is_resolve,
+ or_circuit_t *oncirc, char **resolved_to_hostname);
#ifdef DEBUG_DNS_CACHE
static void _assert_cache_ok(void);
#define assert_cache_ok() _assert_cache_ok()
@@ -523,48 +525,85 @@
* On "pending", link the connection to resolving streams. Otherwise,
* clear its on_circuit field.
*/
-/* XXXX020 Split this into a helper that checks whether there is an answer,
- * and a caller that takes appropriate action based on what happened. */
int
dns_resolve(edge_connection_t *exitconn)
{
+ or_circuit_t *oncirc = TO_OR_CIRCUIT(exitconn->on_circuit);
+ int is_resolve, r;
+ char *hostname = NULL;
+ is_resolve = exitconn->_base.purpose == EXIT_PURPOSE_RESOLVE;
+
+ r = dns_resolve_impl(exitconn, is_resolve, oncirc, &hostname);
+ switch (r) {
+ case 1:
+ if (is_resolve) {
+ if (hostname)
+ send_resolved_hostname_cell(exitconn, hostname);
+ else
+ send_resolved_cell(exitconn, RESOLVED_TYPE_IPV4);
+ } else {
+ exitconn->next_stream = oncirc->n_streams;
+ oncirc->n_streams = exitconn;
+ }
+ break;
+ case 0:
+ exitconn->_base.state = EXIT_CONN_STATE_RESOLVING;
+ exitconn->next_stream = oncirc->resolving_streams;
+ oncirc->resolving_streams = exitconn;
+ break;
+ case -2:
+ case -1:
+ if (is_resolve) {
+ send_resolved_cell(exitconn,
+ (r == -1) ? RESOLVED_TYPE_ERROR : RESOLVED_TYPE_ERROR_TRANSIENT);
+ }
+ //circuit_detach_stream(TO_CIRCUIT(oncirc), exitconn);
+ exitconn->on_circuit = NULL;
+ if (!exitconn->_base.marked_for_close)
+ connection_free(TO_CONN(exitconn));
+ break;
+ default:
+ tor_assert(0);
+ }
+
+ tor_free(hostname);
+ return r;
+}
+
+/** Helper function for dns_resolve: same functionality, but does not handle:
+ * - marking connections on error and clearing their on_circuit
+ * - linking connections to n_streams/resolving_streams,
+ * - sending resolved cells if we have an answer/error right away,
+ *
+ * Returns -2 on a transient error. Sets *<b>hostname_out</b> to a newly
+ * allocated string holding a cached reverse DNS value, if any.
+ */
+static int
+dns_resolve_impl(edge_connection_t *exitconn, int is_resolve,
+ or_circuit_t *oncirc, char **hostname_out)
+{
cached_resolve_t *resolve;
cached_resolve_t search;
pending_connection_t *pending_connection;
struct in_addr in;
time_t now = time(NULL);
- int is_reverse = 0, is_resolve, r;
- or_circuit_t *oncirc = TO_OR_CIRCUIT(exitconn->on_circuit);
+ int is_reverse = 0, r;
assert_connection_ok(TO_CONN(exitconn), 0);
tor_assert(exitconn->_base.s == -1);
assert_cache_ok();
tor_assert(oncirc);
- is_resolve = exitconn->_base.purpose == EXIT_PURPOSE_RESOLVE;
-
/* first check if exitconn->_base.address is an IP. If so, we already
* know the answer. */
if (tor_inet_aton(exitconn->_base.address, &in) != 0) {
exitconn->_base.addr = ntohl(in.s_addr);
exitconn->address_ttl = DEFAULT_DNS_TTL;
- if (is_resolve) {
- send_resolved_cell(exitconn, RESOLVED_TYPE_IPV4);
- } else {
- exitconn->next_stream = oncirc->n_streams;
- oncirc->n_streams = exitconn;
- }
return 1;
}
if (address_is_invalid_destination(exitconn->_base.address, 0)) {
log(LOG_PROTOCOL_WARN, LD_EXIT,
"Rejecting invalid destination address %s",
escaped_safe_str(exitconn->_base.address));
- if (is_resolve)
- send_resolved_cell(exitconn, RESOLVED_TYPE_ERROR);
- //circuit_detach_stream(TO_CIRCUIT(oncirc), exitconn);
- exitconn->on_circuit = NULL;
- if (!exitconn->_base.marked_for_close)
- connection_free(TO_CONN(exitconn));
return -1;
}
@@ -593,12 +632,6 @@
"sending error.",
escaped_safe_str(exitconn->_base.address));
- if (exitconn->_base.purpose == EXIT_PURPOSE_RESOLVE)
- send_resolved_cell(exitconn, RESOLVED_TYPE_ERROR);
- //circuit_detach_stream(TO_CIRCUIT(oncirc), exitconn);
- exitconn->on_circuit = NULL;
- if (!exitconn->_base.marked_for_close)
- connection_free(TO_CONN(exitconn));
return -1;
}
//log_notice(LD_EXIT, "Looks like an address %s",
@@ -620,10 +653,6 @@
log_debug(LD_EXIT,"Connection (fd %d) waiting for pending DNS "
"resolve of %s", exitconn->_base.s,
escaped_safe_str(exitconn->_base.address));
- exitconn->_base.state = EXIT_CONN_STATE_RESOLVING;
-
- exitconn->next_stream = oncirc->resolving_streams;
- oncirc->resolving_streams = exitconn;
return 0;
case CACHE_STATE_CACHED_VALID:
log_debug(LD_EXIT,"Connection (fd %d) found cached answer for %s",
@@ -632,30 +661,15 @@
exitconn->address_ttl = resolve->ttl;
if (resolve->is_reverse) {
tor_assert(is_resolve);
- send_resolved_hostname_cell(exitconn,
- resolve->result.hostname);
+ *hostname_out = tor_strdup(resolve->result.hostname);
} else {
exitconn->_base.addr = resolve->result.addr;
- if (is_resolve)
- send_resolved_cell(exitconn, RESOLVED_TYPE_IPV4);
}
- if (!is_resolve) {
- /* It's a connect; add it into the linked list of n_streams on this
- circuit */
- exitconn->next_stream = oncirc->n_streams;
- oncirc->n_streams = exitconn;
- }
return 1;
case CACHE_STATE_CACHED_FAILED:
log_debug(LD_EXIT,"Connection (fd %d) found cached error for %s",
exitconn->_base.s,
escaped_safe_str(exitconn->_base.address));
- if (is_resolve)
- send_resolved_cell(exitconn, RESOLVED_TYPE_ERROR);
- // circuit_detach_stream(TO_CIRCUIT(oncirc), exitconn);
- exitconn->on_circuit = NULL;
- if (!exitconn->_base.marked_for_close)
- connection_free(TO_CONN(exitconn));
return -1;
case CACHE_STATE_DONE:
log_err(LD_BUG, "Found a 'DONE' dns resolve still in the cache.");
@@ -674,7 +688,6 @@
pending_connection = tor_malloc_zero(sizeof(pending_connection_t));
pending_connection->conn = exitconn;
resolve->pending_connections = pending_connection;
- exitconn->_base.state = EXIT_CONN_STATE_RESOLVING;
/* Add this resolve to the cache and priority queue. */
HT_INSERT(cache_map, &cache_root, resolve);
@@ -684,17 +697,7 @@
escaped_safe_str(exitconn->_base.address));
assert_cache_ok();
- r = launch_resolve(exitconn);
- if (r == 0) {
- exitconn->next_stream = oncirc->resolving_streams;
- oncirc->resolving_streams = exitconn;
- } else {
- tor_assert(r<0);
- exitconn->on_circuit = NULL;
- if (!exitconn->_base.marked_for_close)
- connection_free(TO_CONN(exitconn));
- }
- return r;
+ return launch_resolve(exitconn);
}
/** Log an error and abort if conn is waiting for a DNS resolve.
@@ -1196,7 +1199,8 @@
}
/** For eventdns: start resolving as necessary to find the target for
- * <b>exitconn</b>. Returns -1 on error, 0 on "resolve launched." */
+ * <b>exitconn</b>. Returns -1 on error, -2 on transient errror,
+ * 0 on "resolve launched." */
static int
launch_resolve(edge_connection_t *exitconn)
{
@@ -1231,18 +1235,11 @@
if (r) {
log_warn(LD_EXIT, "eventdns rejected address %s: error %d.",
escaped_safe_str(addr), r);
- if (exitconn->_base.purpose == EXIT_PURPOSE_RESOLVE) {
- if (evdns_err_is_transient(r))
- send_resolved_cell(exitconn, RESOLVED_TYPE_ERROR_TRANSIENT);
- else {
- exitconn->address_ttl = DEFAULT_DNS_TTL;
- send_resolved_cell(exitconn, RESOLVED_TYPE_ERROR);
- }
- }
+ r = evdns_err_is_transient(r) ? -2 : -1;
dns_cancel_pending_resolve(addr); /* also sends end and frees */
tor_free(addr);
}
- return r ? -1 : 0;
+ return r;
}
/** How many requests for bogus addresses have we launched so far? */