From 670e6e019ba28372aa3c54b252eeacb1c237d6dd Mon Sep 17 00:00:00 2001
From: Matthias van der Vlies <674985+killdashnine@users.noreply.github.com>
Date: Fri, 2 Oct 2026 14:20:25 +0200
Subject: [PATCH] [rtp_relay] keep the all-branches session across a failed
 branch

---
 modules/rtp_relay/rtp_relay_ctx.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/modules/rtp_relay/rtp_relay_ctx.c b/modules/rtp_relay/rtp_relay_ctx.c
index e2c15151916..f0bd5a6ef23 100644
--- a/modules/rtp_relay/rtp_relay_ctx.c
+++ b/modules/rtp_relay/rtp_relay_ctx.c
@@ -1875,6 +1875,26 @@ static int rtp_relay_ctx_leg_reply(struct rtp_relay_ctx *ctx, struct sip_msg *ms
 	return ret;
 }
 
+/* a session engaged for all the branches also covers the ones the failure
+ * route may still create (digest retry, failover), so a failed branch must
+ * not destroy it: release the media of the failed attempt and forget its
+ * callee, and the next branch that is forwarded makes a fresh offer */
+static void rtp_relay_sess_failed_branch(struct rtp_relay_ctx *ctx,
+		struct rtp_relay_sess *sess, struct sip_msg *rpl, struct sip_msg *req)
+{
+	struct rtp_relay_session info;
+
+	if (!rtp_sess_late(sess)) {
+		memset(&info, 0, sizeof info);
+		info.msg = (rpl == FAKED_REPLY ? req : rpl);
+		rtp_relay_delete(&info, ctx, sess, RTP_RELAY_CALLEE);
+		rtp_sess_reset_ongoing(sess);
+	}
+	/* the tag belongs to the branch that failed */
+	if (sess->legs[RTP_RELAY_CALLEE])
+		shm_str_clean(&sess->legs[RTP_RELAY_CALLEE]->tag);
+}
+
 static void rtp_relay_ctx_initial_cb(struct cell* t, int type, struct tmcb_params *p)
 {
 	struct rtp_relay_session info;
@@ -1902,6 +1922,11 @@ static void rtp_relay_ctx_initial_cb(struct cell* t, int type, struct tmcb_param
 						rtp_sess_disabled(sess), rtp_sess_pending(sess));
 				goto end;
 			}
+			if (type == TMCB_ON_FAILURE &&
+					sess->index == RTP_RELAY_ALL_BRANCHES) {
+				rtp_relay_sess_failed_branch(ctx, sess, p->rpl, p->req);
+				break;
+			}
 			rtp_relay_fill_sess_leg(ctx, sess, RTP_RELAY_CALLEE,
 					NULL, rtp_relay_ctx_branch());
 			switch (handle_rtp_relay_ctx_leg_reply(ctx, p->rpl, p->req, sess, RTP_RELAY_CALLEE)) {