From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Mon, 7 Aug 2023 12:46:24 +0000 (+0200)
Subject: MINOR: connection: extend conn_reverse() for active reverse
X-Git-Tag: v2.9-dev4~23
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=008e8f67ee55d43041e7e7564ef78e8a0ed1495c;p=thirdparty%2Fhaproxy.git

MINOR: connection: extend conn_reverse() for active reverse

Implement active reverse support inside conn_reverse(). This is used to
transfer the connection from the backend to the frontend side.

A new flag is defined CO_FL_REVERSED which is set just after this
transition. This will be used to identify connections which were
reversed but not yet accepted.
---

diff --git a/include/haproxy/connection-t.h b/include/haproxy/connection-t.h
index cf4ec5a95d..678cc96b29 100644
--- a/include/haproxy/connection-t.h
+++ b/include/haproxy/connection-t.h
@@ -85,7 +85,8 @@ enum {
 	CO_FL_IDLE_LIST     = 0x00000002,  /* 2 = in idle_list, 3 = invalid */
 	CO_FL_LIST_MASK     = 0x00000003,  /* Is the connection in any server-managed list ? */
 
-	/* unused : 0x00000004, 0x00000008 */
+	CO_FL_REVERSED      = 0x00000004,  /* connection has been reversed but not yet accepted */
+	/* unused : 0x00000008 */
 
 	/* unused : 0x00000010 */
 	/* unused : 0x00000020 */
diff --git a/src/connection.c b/src/connection.c
index 6363ff7fd4..70c9e45c28 100644
--- a/src/connection.c
+++ b/src/connection.c
@@ -2440,6 +2440,11 @@ uint64_t conn_calculate_hash(const struct conn_hash_params *params)
 /* Reverse a <conn> connection instance. This effectively moves the connection
  * from frontend to backend side or vice-versa depending on its initial status.
  *
+ * For active reversal, 'reverse' member points to the listener used as the new
+ * connection target. Once transition is completed, the connection needs to be
+ * accepted on the listener to instantiate its parent session before using
+ * streams.
+ *
  * For passive reversal, 'reverse' member points to the server used as the new
  * connection target. Once transition is completed, the connection appears as a
  * normal backend connection.
@@ -2486,7 +2491,10 @@ int conn_reverse(struct connection *conn)
 		conn_set_owner(conn, NULL, NULL);
 	}
 	else {
-		ABORT_NOW();
+		conn_backend_deinit(conn);
+
+		conn->target = conn->reverse.target;
+		conn->flags |= CO_FL_REVERSED;
 	}
 
 	/* Invert source and destination addresses if already set. */