[Levent-commits] SF.net SVN: levent:[1328] branches/patches-1.4/libevent

[<ni...@us...>]

Revision: 1328
          http://levent.svn.sourceforge.net/levent/?rev=1328&view=rev
Author:   nickm
Date:     2009-06-24 22:39:12 +0000 (Wed, 24 Jun 2009)

Log Message:
-----------
Let evdns keep working when our IP changes.  Fix by Christopher Davis; backported by nickm.

Modified Paths:
--------------
    branches/patches-1.4/libevent/ChangeLog
    branches/patches-1.4/libevent/evdns.c

Modified: branches/patches-1.4/libevent/ChangeLog
===================================================================
--- branches/patches-1.4/libevent/ChangeLog	2009-06-24 22:39:03 UTC (rev 1327)
+++ branches/patches-1.4/libevent/ChangeLog	2009-06-24 22:39:12 UTC (rev 1328)
@@ -4,6 +4,7 @@
  o Use __VA_ARGS__ syntax for varargs macros in event_rpcgen when compiler is not GCC.
  o Activate fd events in a pseudorandom order with O(N) backends, so that we don't systematically favor low fds (select) or earlier-added fds (poll, win32).
  o Fix another pair of fencepost bugs in epoll.c.  [Patch from Adam Langley.]
+ o Do not break evdns connections to nameservers when our IP changes.
 
 Changes in 1.4.11-stable:
  o Fix a bug when removing a timeout from the heap. [Patch from Marko Kreen]

Modified: branches/patches-1.4/libevent/evdns.c
===================================================================
--- branches/patches-1.4/libevent/evdns.c	2009-06-24 22:39:03 UTC (rev 1327)
+++ branches/patches-1.4/libevent/evdns.c	2009-06-24 22:39:12 UTC (rev 1328)
@@ -209,6 +209,7 @@
 struct nameserver {
 	int socket;  /* a connected UDP socket */
 	u32 address;
+	u16 port;
 	int failed_times;  /* number of times which we have given this server a chance */
 	int timedout;  /* number of times in a row a request has timed out */
 	struct event event;
@@ -1150,19 +1151,38 @@
 	}
 }
 
+static int
+address_is_correct(struct nameserver *ns, struct sockaddr *sa, socklen_t slen)
+{
+	struct sockaddr_in *sin = (struct sockaddr_in*) sa;
+	if (sa->sa_family != AF_INET || slen != sizeof(struct sockaddr_in))
+		return 0;
+	if (sin->sin_addr.s_addr != ns->address)
+		return 0;
+	return 1;
+}
+
 /* this is called when a namesever socket is ready for reading */
 static void
 nameserver_read(struct nameserver *ns) {
 	u8 packet[1500];
+	struct sockaddr_storage ss;
+	socklen_t addrlen = sizeof(ss);
 
 	for (;;) {
-          	const int r = recv(ns->socket, packet, sizeof(packet), 0);
+          	const int r = recvfrom(ns->socket, packet, sizeof(packet), 0,
+		    (struct sockaddr*)&ss, &addrlen);
 		if (r < 0) {
 			int err = last_error(ns->socket);
 			if (error_is_eagain(err)) return;
 			nameserver_failed(ns, strerror(err));
 			return;
 		}
+		if (!address_is_correct(ns, (struct sockaddr*)&ss, addrlen)) {
+			log(EVDNS_LOG_WARN, "Address mismatch on received "
+			    "DNS packet.");
+			return;
+		}
 		ns->timedout = 0;
 		reply_parse(packet, r);
 	}
@@ -1890,7 +1910,15 @@
 /*   2 other failure */
 static int
 evdns_request_transmit_to(struct request *req, struct nameserver *server) {
-	const int r = send(server->socket, req->request, req->request_len, 0);
+	struct sockaddr_in sin;
+	int r;
+	memset(&sin, 0, sizeof(sin));
+	sin.sin_addr.s_addr = req->ns->address;
+	sin.sin_port = req->ns->port;
+	sin.sin_family = AF_INET;
+
+	r = sendto(server->socket, req->request, req->request_len, 0,
+	    (struct sockaddr*)&sin, sizeof(sin));
 	if (r < 0) {
 		int err = last_error(server->socket);
 		if (error_is_eagain(err)) return 1;
@@ -2085,7 +2113,6 @@
 
 	const struct nameserver *server = server_head, *const started_at = server_head;
 	struct nameserver *ns;
-	struct sockaddr_in sin;
 	int err = 0;
 	if (server) {
 		do {
@@ -2104,15 +2131,9 @@
 	ns->socket = socket(PF_INET, SOCK_DGRAM, 0);
 	if (ns->socket < 0) { err = 1; goto out1; }
         evutil_make_socket_nonblocking(ns->socket);
-	sin.sin_addr.s_addr = address;
-	sin.sin_port = htons(port);
-	sin.sin_family = AF_INET;
-	if (connect(ns->socket, (struct sockaddr *) &sin, sizeof(sin)) != 0) {
-		err = 2;
-		goto out2;
-	}
 
 	ns->address = address;
+	ns->port = htons(port);
 	ns->state = 1;
 	event_set(&ns->event, ns->socket, EV_READ | EV_PERSIST, nameserver_ready_callback, ns);
 	if (event_add(&ns->event, NULL) < 0) {


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