dovecot-2.2: lib-imap-client: If connect() fails immediately, lo...

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-2.2/rev/e157d13efac9
changeset: 19055:e157d13efac9
user:      Timo Sirainen <tss at iki.fi>
date:      Tue Sep 01 16:25:11 2015 +0300
description:
lib-imap-client: If connect() fails immediately, log an error and retry the next IP.
Only if all IPs fail return a full failure. This is mainly intended to skip
IPv6 addresses when IPv6 connectivity doesn't work.

diffstat:

 src/lib-imap-client/imapc-connection.c |  23 +++++++++++++++++------
 1 files changed, 17 insertions(+), 6 deletions(-)

diffs (37 lines):

diff -r c0e61e4f47ec -r e157d13efac9 src/lib-imap-client/imapc-connection.c
--- a/src/lib-imap-client/imapc-connection.c	Tue Sep 01 00:11:37 2015 +0300
+++ b/src/lib-imap-client/imapc-connection.c	Tue Sep 01 16:25:11 2015 +0300
@@ -1564,16 +1564,27 @@
 static void imapc_connection_connect_next_ip(struct imapc_connection *conn)
 {
 	const struct ip_addr *ip;
+	unsigned int i;
 	int fd;
 
 	i_assert(conn->client->set.max_idle_time > 0);
 
-	conn->prev_connect_idx = (conn->prev_connect_idx+1) % conn->ips_count;
-	ip = &conn->ips[conn->prev_connect_idx];
-	fd = net_connect_ip(ip, conn->client->set.port, NULL);
-	if (fd == -1) {
-		imapc_connection_set_disconnected(conn);
-		return;
+	for (i = 0;;) {
+		conn->prev_connect_idx = (conn->prev_connect_idx+1) % conn->ips_count;
+		ip = &conn->ips[conn->prev_connect_idx];
+		fd = net_connect_ip(ip, conn->client->set.port, NULL);
+		if (fd != -1)
+			break;
+
+		/* failed to connect to one of the IPs immediately
+		   (e.g. IPv6 address without connectivity). try all IPs
+		   before failing completely. */
+		i_error("net_connect_ip(%s:%u) failed: %m",
+			net_ip2addr(ip), conn->client->set.port);
+		if (++i == conn->ips_count) {
+			imapc_connection_set_disconnected(conn);
+			return;
+		}
 	}
 	conn->fd = fd;
 	conn->input = conn->raw_input = i_stream_create_fd(fd, (size_t)-1, FALSE);