BUG/MINOR: proto_reverse_connect: set default maxconn

If maxconn is not set for preconnect, it assumes we want to establish a
single connection. However, this does not work properly in case the
connection is closed after reversal. Listener is not resumed by protocol
layer to attempt a new preconnect.

To fix this, explicitely set maxconn to 1 in the listener instance if
none is defined. This ensures the behavior is consistent. A BUG_ON() has
been added to validate we never try to use a listener with a 0 maxconn.

diff --git a/src/proto_reverse_connect.c b/src/proto_reverse_connect.c
index f370ce2273d6cb9ca032914c50877ae75ddb36fa..ef8fe21d48a130c4a95752656f810790fd7f5fa1 100644 (file)
--- a/src/proto_reverse_connect.c
+++ b/src/proto_reverse_connect.c
@@ -164,6 +164,12 @@ int rev_bind_listener(struct listener *listener, char *errmsg, int errlen)
        task->context = listener;
        listener->rx.reverse_connect.task = task;
 
+       /* Set a default maxconn to 1. This ensures listener is properly
+        * reenable each time we fall back below it on connection error.
+        */
+       if (!listener->bind_conf->maxconn)
+               listener->bind_conf->maxconn = 1;
+
        name = strdup(listener->bind_conf->reverse_srvname);
        if (!name) {
                snprintf(errmsg, errlen, "Out of memory.");
@@ -229,8 +235,13 @@ struct connection *rev_accept_conn(struct listener *l, int *status)
        struct connection *conn = l->rx.reverse_connect.pend_conn;
 
        if (!conn) {
+               /* Reverse connect listener must have an explicit maxconn set
+                * to ensure it is reenabled on connection error.
+                */
+               BUG_ON(!l->bind_conf->maxconn);
+
                /* Instantiate a new conn if maxconn not yet exceeded. */
-               if (l->bind_conf->maxconn && l->nbconn <= l->bind_conf->maxconn) {
+               if (l->nbconn <= l->bind_conf->maxconn) {
                        l->rx.reverse_connect.pend_conn = new_reverse_conn(l, l->rx.reverse_connect.srv);
                        if (!l->rx.reverse_connect.pend_conn) {
                                *status = CO_AC_PAUSE;