[MEDIUM] session: account per-listener connections

In order to merge the unix session handling code, we have to maintain
the number of per-listener connections in the session. This was only
performed for unix sockets till now.

src/client.c

@@ -108,6 +108,16 @@ int event_accept(int fd) {
 			}
 		}
 
+		if (l->nbconn >= l->maxconn) {
+			/* too many connections, we shoot this one and return.
+			 * FIXME: it would be better to simply switch the listener's
+			 * state to LI_FULL and disable the FD. We could re-enable
+			 * it upon fd_delete(), but this requires all protocols to
+			 * be switched.
+			 */
+			goto out_close;
+		}
+
 		if ((s = pool_alloc2(pool2_session)) == NULL) { /* disable this proxy for a while */
 			Alert("out of memory in event_accept().\n");
 			EV_FD_CLR(fd, DIR_RD);
@@ -458,6 +468,12 @@ int event_accept(int fd) {
 		 */
 		task_wakeup(t, TASK_WOKEN_INIT);
 
+		l->nbconn++; /* warning! right now, it's up to the handler to decrease this */
+		if (l->nbconn >= l->maxconn) {
+			EV_FD_CLR(l->fd, DIR_RD);
+			l->state = LI_FULL;
+		}
+
 		p->feconn++;  /* beconn will be increased later */
 		if (p->feconn > p->feconn_max)
 			p->feconn_max = p->feconn;

src/session.c

@@ -1206,6 +1206,13 @@ resync_stream_interface:
 	if (s->flags & SN_BE_ASSIGNED)
 		s->be->beconn--;
 	actconn--;
+	s->listener->nbconn--;
+	if (s->listener->state == LI_FULL &&
+	    s->listener->nbconn < s->listener->maxconn) {
+		/* we should reactivate the listener */
+		EV_FD_SET(s->listener->fd, DIR_RD);
+		s->listener->state = LI_READY;
+	}
 
 	if (unlikely((global.mode & MODE_DEBUG) &&
 		     (!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE)))) {