BUG/MEDIUM: servers: Attempt to reuse an unfinished connection on retry.

In connect_server(), if the previous connection failed, but had an alpn, no
mux was created, and thus the stream_interface's endpoint would be the
connection. In this case, instead of forgetting about it, and overriding
the stream_interface's endpoint later, try to reuse the connection, or the
connection will still be in the session's connection list, and will reference
to a stream that was probably destroyed.

This should be backported to 1.9.

diff --git a/src/backend.c b/src/backend.c
index 59324538d63e876bddf3cda81fc0e9850b93f94d..6f9557563d812509e8a859cc98e8835e02ffe49a 100644 (file)
--- a/src/backend.c
+++ b/src/backend.c
@@ -1154,14 +1154,25 @@ int connect_server(struct stream *s)
         * to use it.
         */
        srv_cs = objt_cs(s->si[1].end);
-       if (srv_cs) {
-               old_conn = srv_conn = cs_conn(srv_cs);
-               if (old_conn && (!old_conn->target || old_conn->target == s->target)) {
-                       old_conn->flags &= ~(CO_FL_ERROR | CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH);
-                       srv_cs->flags &= ~(CS_FL_ERROR | CS_FL_EOS | CS_FL_REOS);
+       if (!srv_cs)
+               srv_conn = objt_conn(s->si[1].end);
+       else
+               srv_conn = cs_conn(srv_cs);
+
+       if (srv_conn) {
+               if (!srv_conn->target || srv_conn->target == s->target) {
+                       srv_conn->flags &= ~(CO_FL_ERROR | CO_FL_SOCK_RD_SH | CO_FL_SOCK_WR_SH);
+                       if (srv_cs)
+                               srv_cs->flags &= ~(CS_FL_ERROR | CS_FL_EOS | CS_FL_REOS);
                        reuse = 1;
+                       old_conn = srv_conn;
+               } else {
+                       srv_conn = NULL;
+                       si_release_endpoint(&s->si[1]);
                }
-       } else {
+       }
+
+       if (!old_conn) {
                struct sess_srv_list *srv_list;
                list_for_each_entry(srv_list, &s->sess->srv_list, srv_list) {
                        if (srv_list->target == s->target) {
@@ -1301,7 +1312,7 @@ int connect_server(struct stream *s)
                /* We already created a cs earlier when using http_proxy, so
                 * only create a new one if we don't have one already.
                 */
-               if (!srv_cs) {
+               if (!srv_cs && srv_conn->mux) {
                        int avail = srv_conn->mux->avail_streams(srv_conn);
 
                        if (avail <= 1) {