From: Olivier Houchard <ohouchard@haproxy.com>
Date: Sun, 14 Dec 2025 15:10:21 +0000 (+0100)
Subject: BUG/MEDIUM: quic: Don't try to use hystart if not implemented
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a08bc468d2c7c4bb7df84c2408d48a82f01220a0;p=thirdparty%2Fhaproxy.git

BUG/MEDIUM: quic: Don't try to use hystart if not implemented

Not every CC algos implement hystart, so only call the method if it is
actually there. Failure to do so will cause crashes if hystart is on,
and the algo doesn't implement it.

This should fix github issue #3218

This should be backported up to 3.0.
---

diff --git a/src/quic_tx.c b/src/quic_tx.c
index 7f5647e81..ac331ae94 100644
--- a/src/quic_tx.c
+++ b/src/quic_tx.c
@@ -439,7 +439,8 @@ static int qc_send_ppkts(struct buffer *buf, struct quic_conn *qc)
 			}
 			qc->path->in_flight += pkt->in_flight_len;
 			pkt->pktns->tx.in_flight += pkt->in_flight_len;
-			if (quic_tune_test(QUIC_TUNE_FB_CC_HYSTART, qc) && pkt->pktns == qc->apktns)
+			if (quic_tune_test(QUIC_TUNE_FB_CC_HYSTART, qc) && pkt->pktns == qc->apktns &&
+			    cc->algo->hystart_start_round != NULL)
 				cc->algo->hystart_start_round(cc, pkt->pn_node.key);
 			if (pkt->in_flight_len)
 				qc_set_timer(qc);