[MEDIUM] in the request, always consider empty cookies as invalid.
This solves a problem of unwanted stickyness to backup servers when some
clients incidentely memorize an empty cookie.
diff --git a/haproxy.c b/haproxy.c
index 0ca75ca..bdcb582 100644
--- a/haproxy.c
+++ b/haproxy.c
@@ -4082,7 +4082,13 @@
/* Here, we'll look for the first running server which supports the cookie.
* This allows to share a same cookie between several servers, for example
* to dedicate backup servers to specific servers only.
+ * However, to prevent clients from sticking to cookie-less backup server
+ * when they have incidentely learned an empty cookie, we simply ignore
+ * empty cookies and mark them as invalid.
*/
+ if (delim == p3)
+ srv = NULL;
+
while (srv) {
if ((srv->cklen == delim - p3) && !memcmp(p3, srv->cookie, delim - p3)) {
if (srv->state & SRV_RUNNING || t->proxy->options & PR_O_PERSIST) {