From 462f64b6b993d46f5b61c7e2333cc526d15ba884 Mon Sep 17 00:00:00 2001
From: Nick Mathewson <nickm@torproject.org>
Date: Tue, 6 Jan 2009 20:50:55 +0000
Subject: [PATCH] Make outgoing DNS requests respect OutboundBindAddress. Fixes
 the bug part of bug 789.

svn:r17983
---
 ChangeLog         |  4 +++-
 src/or/dns.c      | 19 +++++++++++++++++++
 src/or/dnsserv.c  |  2 +-
 src/or/eventdns.c | 26 ++++++++++++++++++++++++++
 src/or/eventdns.h |  1 +
 5 files changed, 50 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 7681dd8d6..f04b6cb0b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 Changes in version 0.2.1.11-alpha - 2009-01-??
-
+  o Minor bugfixes:
+    - Make outbound DNS packets respect the OutboundBindAddress setting.
+      Fixes the bug part of bug 798.
 
 Changes in version 0.2.1.10-alpha - 2009-01-06
   o Major bugfixes:
diff --git a/src/or/dns.c b/src/or/dns.c
index 3266cf99d..f8191679b 100644
--- a/src/or/dns.c
+++ b/src/or/dns.c
@@ -1102,6 +1102,25 @@ configure_nameservers(int force)
     conf_fname = "/etc/resolv.conf";
 #endif
 
+  if (options->OutboundBindAddress) {
+    tor_addr_t addr;
+    if (tor_addr_from_str(&addr, options->OutboundBindAddress) < 0) {
+      log_warn(LD_CONFIG,"Outbound bind address '%s' didn't parse. Ignoring.",
+               options->OutboundBindAddress);
+    } else {
+      int socklen;
+      struct sockaddr_storage ss;
+      socklen = tor_addr_to_sockaddr(&addr, 0,
+                                     (struct sockaddr *)&ss, sizeof(ss));
+      if (socklen < 0) {
+        log_warn(LD_BUG, "Couldn't convert outboung bind address to sockaddr."
+                 " Ignoring.");
+      } else {
+        evdns_set_default_outgoing_bind_address((struct sockaddr *)&ss,socklen);
+      }
+    }
+  }
+
   evdns_set_log_fn(evdns_log_cb);
   if (conf_fname) {
     if (stat(conf_fname, &st)) {
diff --git a/src/or/dnsserv.c b/src/or/dnsserv.c
index 11002e9d7..36d072110 100644
--- a/src/or/dnsserv.c
+++ b/src/or/dnsserv.c
@@ -294,7 +294,7 @@ void
 dnsserv_configure_listener(connection_t *conn)
 {
   tor_assert(conn);
-  tor_assert(conn->s);
+  tor_assert(conn->s >= 0);
   tor_assert(conn->type == CONN_TYPE_AP_DNS_LISTENER);
 
   conn->dns_server_port = evdns_add_server_port(conn->s, 0,
diff --git a/src/or/eventdns.c b/src/or/eventdns.c
index 60f08265c..6e4e5e25b 100644
--- a/src/or/eventdns.c
+++ b/src/or/eventdns.c
@@ -2203,6 +2203,23 @@ evdns_clear_nameservers_and_suspend(void)
 	return 0;
 }
 
+static struct sockaddr_storage global_bind_address;
+static socklen_t global_bind_addrlen = 0;
+static int global_bind_addr_is_set = 0;
+void
+evdns_set_default_outgoing_bind_address(const struct sockaddr *addr,
+										socklen_t addrlen)
+{
+	memset(&global_bind_address, 0, sizeof(global_bind_address));
+	if (addr) {
+		assert(addrlen <= sizeof(global_bind_address));
+		memcpy(&global_bind_address, addr, addrlen);
+		global_bind_addrlen = addrlen;
+		global_bind_addr_is_set = 1;
+	} else {
+		global_bind_addr_is_set = 0;
+	}
+}
 
 /* exported function */
 int
@@ -2251,6 +2268,15 @@ _evdns_nameserver_add_impl(const struct sockaddr *address,
 	fcntl(ns->socket, F_SETFL, O_NONBLOCK);
 #endif
 
+	if (global_bind_addr_is_set) {
+		if (bind(ns->socket, (struct sockaddr *)&global_bind_address,
+				 global_bind_addrlen) < 0) {
+			log(EVDNS_LOG_DEBUG, "Couldn't bind to outgoing address.");
+			err = 2;
+			goto out2;
+		}
+	}
+
 	if (connect(ns->socket, address, addrlen) != 0) {
 		log(EVDNS_LOG_DEBUG, "Couldn't open socket to nameserver.");
 		err = 2;
diff --git a/src/or/eventdns.h b/src/or/eventdns.h
index 8d9a0b8fb..d3d359d2f 100644
--- a/src/or/eventdns.h
+++ b/src/or/eventdns.h
@@ -264,6 +264,7 @@ int evdns_clear_nameservers_and_suspend(void);
 int evdns_resume(void);
 int evdns_nameserver_ip_add(const char *ip_as_string);
 int evdns_nameserver_sockaddr_add(const struct sockaddr *sa, socklen_t len);
+void evdns_set_default_outgoing_bind_address(const struct sockaddr *addr, socklen_t addrlen);
 int evdns_resolve_ipv4(const char *name, int flags, evdns_callback_type callback, void *ptr);
 int evdns_resolve_ipv6(const char *name, int flags, evdns_callback_type callback, void *ptr);
 struct in_addr;