BUG/MEDIUM: mux-h1: Fix how timeouts are applied on H1 connections

There were several flaws in the way the different timeouts were applied on
H1 connections. First, the H1C task handling timeouts was not created if no
client/server timeout was specified. But there are other timeouts to
consider. First, the client-fin/server-fin timeouts. But for frontend
connections, http-keey-alive and http-request timeouts may also be used. And
finally, on soft-stop, the close-spread-time value must be considered too.

So at the end, it is probably easier to always create a task to manage H1C
timeouts. Especially since the client/server timeouts are most often set.

Then, when the expiration date of the H1C's task must only be updated if the
considered timeout is set. So tick_add_ifset() must be used instead of
tick_add(). Otherwise, if a timeout is undefined, the taks may expire
immediately while it should in fact never expire.

Finally, the idle expiration date must only be considered for idle
connections.

This patch should be backported in all stable versions, at least as far as
2.6. On the 2.4, it will have to be slightly adapted for the idle_exp
part. On 2.2 and 2.0, the patch will have to be rewrite because
h1_refresh_timeout() is quite different.

Author: capflam

src/mux_h1.c

@@ -694,24 +694,24 @@ static void h1_refresh_timeout(struct h1c *h1c)
 			 * timeouts so that we don't hang too long on clients that have
 			 * gone away (especially in tunnel mode).
 			 */
-			h1c->task->expire = tick_add(now_ms, h1c->shut_timeout);
+			h1c->task->expire = tick_add_ifset(now_ms, h1c->shut_timeout);
 			TRACE_DEVEL("refreshing connection's timeout (dead or half-closed)", H1_EV_H1C_SEND|H1_EV_H1C_RECV, h1c->conn);
 			is_idle_conn = 1;
 		}
 		else if (b_data(&h1c->obuf)) {
 			/* alive connection with pending outgoing data, need a timeout (server or client). */
-			h1c->task->expire = tick_add(now_ms, h1c->timeout);
+			h1c->task->expire = tick_add_ifset(now_ms, h1c->timeout);
 			TRACE_DEVEL("refreshing connection's timeout (pending outgoing data)", H1_EV_H1C_SEND|H1_EV_H1C_RECV, h1c->conn);
 		}
 		else if (!(h1c->flags & H1C_F_IS_BACK) && (h1c->state == H1_CS_IDLE)) {
 			/* idle front connections. */
-			h1c->task->expire = (tick_isset(h1c->idle_exp) ? h1c->idle_exp : tick_add(now_ms, h1c->timeout));
+			h1c->task->expire = (tick_isset(h1c->idle_exp) ? h1c->idle_exp : tick_add_ifset(now_ms, h1c->timeout));
 			TRACE_DEVEL("refreshing connection's timeout (idle front h1c)", H1_EV_H1C_SEND|H1_EV_H1C_RECV, h1c->conn);
 			is_idle_conn = 1;
 		}
 		else if (!(h1c->flags & H1C_F_IS_BACK) && (h1c->state != H1_CS_RUNNING)) {
 			/* alive front connections waiting for a fully usable stream need a timeout. */
-			h1c->task->expire = tick_add(now_ms, h1c->timeout);
+			h1c->task->expire = tick_first(h1c->idle_exp, tick_add_ifset(now_ms, h1c->timeout));
 			TRACE_DEVEL("refreshing connection's timeout (alive front h1c but not ready)", H1_EV_H1C_SEND|H1_EV_H1C_RECV, h1c->conn);
 			/* A frontend connection not yet ready could be treated the same way as an idle
 			 * one in case of soft-close.
@@ -724,9 +724,6 @@ static void h1_refresh_timeout(struct h1c *h1c)
 			TRACE_DEVEL("no connection timeout (alive back h1c or front h1c with an SC)", H1_EV_H1C_SEND|H1_EV_H1C_RECV, h1c->conn);
 		}
 
-		/* Finally set the idle expiration date if shorter */
-		h1c->task->expire = tick_first(h1c->task->expire, h1c->idle_exp);
-
 		if ((h1c->px->flags & (PR_FL_DISABLED|PR_FL_STOPPED)) &&
 		     is_idle_conn && tick_isset(global.close_spread_end)) {
 			/* If a soft-stop is in progress and a close-spread-time
@@ -1276,19 +1273,16 @@ static int h1_init(struct connection *conn, struct proxy *proxy, struct session
 		LIST_APPEND(&mux_stopping_data[tid].list,
 		            &h1c->conn->stopping_list);
 	}
-	if (tick_isset(h1c->timeout)) {
-		t = task_new_here();
-		if (!t) {
-			TRACE_ERROR("H1C task allocation failure", H1_EV_H1C_NEW|H1_EV_H1C_END|H1_EV_H1C_ERR);
-			goto fail;
-		}
 
-		h1c->task = t;
-		t->process = h1_timeout_task;
-		t->context = h1c;
-
-		t->expire = tick_add(now_ms, h1c->timeout);
+	t = task_new_here();
+	if (!t) {
+		TRACE_ERROR("H1C task allocation failure", H1_EV_H1C_NEW|H1_EV_H1C_END|H1_EV_H1C_ERR);
+		goto fail;
 	}
+	h1c->task = t;
+	t->process = h1_timeout_task;
+	t->context = h1c;
+	t->expire = tick_add_ifset(now_ms, h1c->timeout);
 
 	conn->ctx = h1c;