From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Mon, 14 Aug 2023 08:52:50 +0000 (+0200)
Subject: MINOR: proto_reverse_connect: handle early error before reversal
X-Git-Tag: v2.9-dev4~19
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b130f8dbc343640fd3867168f9e8f0c16ad5e9d0;p=thirdparty%2Fhaproxy.git

MINOR: proto_reverse_connect: handle early error before reversal

An error can occured on a reverse connection before accept is completed.
In this case, no parent session can be notified. Instead, wake up the
receiver task on conn_create_mux().

As a counterpart to this, receiver task is extended to match CO_FL_ERROR
flag on pending connection. In this case, the onnection is freed. The
task is then requeued with a 1 second delay to start a new reverse
connection attempt.
---

diff --git a/src/connection.c b/src/connection.c
index 5ebc1d90a9..8a7db31637 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -91,8 +91,24 @@ int conn_create_mux(struct connection *conn)
 		return 0;
 fail:
 		/* let the upper layer know the connection failed */
-		if (sc)
+		if (sc) {
 			sc->app_ops->wake(sc);
+		}
+		else if (conn_reverse_in_preconnect(conn)) {
+			struct listener *l = conn_active_reverse_listener(conn);
+
+			/* If mux init failed, consider connection on error.
+			 * This is necessary to ensure connection is freed by
+			 * proto-reverse-connect receiver task.
+			 */
+			if (!conn->mux)
+				conn->flags |= CO_FL_ERROR;
+
+			/* If connection is interrupted  without CO_FL_ERROR, receiver task won't free it. */
+			BUG_ON(!(conn->flags & CO_FL_ERROR));
+
+			task_wakeup(l->rx.reverse_connect.task, TASK_WOKEN_ANY);
+		}
 		return -1;
 	} else
 		return conn_complete_session(conn);
@@ -543,6 +559,8 @@ void conn_free(struct connection *conn)
 		/* Receiver must reference a reverse connection as pending. */
 		BUG_ON(!l->rx.reverse_connect.pend_conn);
 		l->rx.reverse_connect.pend_conn = NULL;
+		l->rx.reverse_connect.task->expire = MS_TO_TICKS(now_ms + 1000);
+		task_queue(l->rx.reverse_connect.task);
 	}
 
 	conn_force_unsubscribe(conn);
diff --git a/src/proto_reverse_connect.c b/src/proto_reverse_connect.c
index 1bbc70957e..6944d6c391 100644
--- a/src/proto_reverse_connect.c
+++ b/src/proto_reverse_connect.c
@@ -107,11 +107,22 @@ struct task *rev_process(struct task *task, void *ctx, unsigned int state)
 	struct connection *conn = l->rx.reverse_connect.pend_conn;
 
 	if (conn) {
-		/* Spurrious receiver task wake up when pend_conn is not ready/on error. */
-		BUG_ON(!(conn->flags & CO_FL_REVERSED));
-		/* A connection is ready to be accepted. */
-		listener_accept(l);
-		l->rx.reverse_connect.task->expire = TICK_ETERNITY;
+		if (conn->flags & CO_FL_ERROR) {
+			conn_full_close(conn);
+			conn_free(conn);
+			l->rx.reverse_connect.pend_conn = NULL;
+
+			/* Retry on 1s on error. */
+			l->rx.reverse_connect.task->expire = MS_TO_TICKS(now_ms + 1000);
+		}
+		else {
+			/* Spurrious receiver task wake up when pend_conn is not ready/on error. */
+			BUG_ON(!(conn->flags & CO_FL_REVERSED));
+
+			/* A connection is ready to be accepted. */
+			listener_accept(l);
+			l->rx.reverse_connect.task->expire = TICK_ETERNITY;
+		}
 	}
 	else {
 		/* No pending reverse connection, prepare a new one. Store it in the