MINOR: proto_reverse_connect: refactor preconnect failure

When a connection is freed during preconnect before reversal, the error
must be notified to the listener to remove any connection reference and
rearm a new preconnect attempt. Currently, this can occur through 2 code
paths :
* conn_free() called directly by H2 mux
* error during conn_create_mux(). For this case, connection is flagged
  with CO_FL_ERROR and reverse_connect task is woken up. The process
  task handler is then responsible to call conn_free() for such
  connection.

Duplicated steps where done both in conn_free() and process task
handler. These are now removed. To facilitate code maintenance,
dedicated operation have been centralized in a new function
rev_notify_preconn_err() which is called by conn_free().

diff --git a/include/haproxy/proto_reverse_connect.h b/include/haproxy/proto_reverse_connect.h
index e40a0217a8f6e0241e52eb24a98a5cde60bb87bf..0c07356e090408312df8aa3a550a24c316411403 100644 (file)
--- a/include/haproxy/proto_reverse_connect.h
+++ b/include/haproxy/proto_reverse_connect.h
@@ -16,4 +16,6 @@ int rev_set_affinity(struct connection *conn, int new_tid);
 
 int rev_accepting_conn(const struct receiver *rx);
 
+void rev_notify_preconn_err(struct listener *l);
+
 #endif /* _HAPROXY_PROTO_REVERSE_CONNECT_H */

diff --git a/src/connection.c b/src/connection.c
index 5f7226aaeca6ad09f8f8e7831509b45310fd7f2e..9c127c0fb1423867ba12843e068a3f29b592ff94 100644 (file)
--- a/src/connection.c
+++ b/src/connection.c
@@ -25,6 +25,7 @@
 #include <haproxy/log-t.h>
 #include <haproxy/namespace.h>
 #include <haproxy/net_helper.h>
+#include <haproxy/proto_reverse_connect.h>
 #include <haproxy/proto_tcp.h>
 #include <haproxy/sample.h>
 #include <haproxy/sc_strm.h>
@@ -579,14 +580,7 @@ void conn_free(struct connection *conn)
 
        if (conn_reverse_in_preconnect(conn)) {
                struct listener *l = conn_active_reverse_listener(conn);
-
-               /* For the moment reverse connection are bound only on first thread. */
-               BUG_ON(tid != 0);
-               /* 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);
+               rev_notify_preconn_err(l);
        }
 
        conn_force_unsubscribe(conn);

diff --git a/src/proto_reverse_connect.c b/src/proto_reverse_connect.c
index ef8fe21d48a130c4a95752656f810790fd7f5fa1..cc6a6dfb0da9064b5ea1c36764efc71f211e8700 100644 (file)
--- a/src/proto_reverse_connect.c
+++ b/src/proto_reverse_connect.c
@@ -102,6 +102,26 @@ static struct connection *new_reverse_conn(struct listener *l, struct server *sr
        return NULL;
 }
 
+/* Report that a connection used for preconnect on listener <l> is freed before
+ * reversal is completed. This is used to cleanup any reference to the
+ * connection and rearm a new preconnect attempt.
+ */
+void rev_notify_preconn_err(struct listener *l)
+{
+       /* For the moment reverse connection are bound only on first thread. */
+       BUG_ON(tid != 0);
+
+       /* Receiver must reference a reverse connection as pending. */
+       BUG_ON(!l->rx.reverse_connect.pend_conn);
+
+       /* Remove reference to the freed connection. */
+       l->rx.reverse_connect.pend_conn = NULL;
+
+       /* Rearm a new preconnect attempt. */
+       l->rx.reverse_connect.task->expire = MS_TO_TICKS(now_ms + 1000);
+       task_queue(l->rx.reverse_connect.task);
+}
+
 struct task *rev_process(struct task *task, void *ctx, unsigned int state)
 {
        struct listener *l = ctx;
@@ -111,10 +131,9 @@ struct task *rev_process(struct task *task, void *ctx, unsigned int state)
                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);
+                       /* conn_free() must report preconnect failure using rev_notify_preconn_err(). */
+                       BUG_ON(l->rx.reverse_connect.pend_conn);
                }
                else {
                        /* Spurrious receiver task wake up when pend_conn is not ready/on error. */