From 5cfb4edca75dca8bc5c3ce9c2b86aadca477a3e3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20L=C3=A9caille?= <flecaille@haproxy.com>
Date: Wed, 30 Mar 2022 14:44:49 +0200
Subject: [PATCH] BUG/MINOR: quic: Do not probe from an already probing packet
 number space

During a handshake, after having prepared a probe upon a PTO expiration from
process_timer(), we wake up the I/O handler to make it send probing packets.
This handler first treat incoming packets  which trigger a fast retransmission
leading to send too much probing (duplicated) packets. In this cas we cancel
the fast retranmission.
---
 src/xprt_quic.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index dd9c3543a..c48d1c251 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -2320,6 +2320,15 @@ static void qc_prep_hdshk_fast_retrans(struct quic_conn *qc)
 	struct quic_tx_packet *pkt;
 	struct list *tmp = &itmp;
 
+	/* Do not probe from a packet number space if some probing
+	 * was already asked.
+	 */
+	if (qel->pktns->tx.pto_probe) {
+		qel = hqel;
+		if (qel->pktns->tx.pto_probe)
+			return;
+	}
+
  start:
 	pkt = NULL;
 	pkts = &qel->pktns->tx.pkts;