From: Frédéric Lécaille <flecaille@haproxy.com>
Date: Thu, 21 Apr 2022 15:58:46 +0000 (+0200)
Subject: MINOR: quic: Do not retransmit frames from coalesced packets
X-Git-Tag: v2.6-dev8~33
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b44cbc68a67f401f0b4cbf2683ea9ca49b3453a5;p=thirdparty%2Fhaproxy.git

MINOR: quic: Do not retransmit frames from coalesced packets

Add QUIC_FL_TX_PACKET_COALESCED flag to mark a TX packet as coalesced with others
to build a datagram.
Ensure we do not directly retransmit frames from such coalesced packets. They must
be retransmitted from their packet number spaces to avoid duplications.
---

diff --git a/include/haproxy/xprt_quic-t.h b/include/haproxy/xprt_quic-t.h
index 6c4336cc47..a7ee4e856b 100644
--- a/include/haproxy/xprt_quic-t.h
+++ b/include/haproxy/xprt_quic-t.h
@@ -518,6 +518,8 @@ struct quic_rx_strm_frm {
 #define QUIC_FL_TX_PACKET_CC            (1UL << 2)
 /* Flag a sent packet as containg an ACK frame */
 #define QUIC_FL_TX_PACKET_ACK           (1UL << 3)
+/* Flag a sent packet as being coalesced to another one in the same datagram */
+#define QUIC_FL_TX_PACKET_COALESCED     (1UL << 4)
 
 /* Structure to store enough information about TX QUIC packets. */
 struct quic_tx_packet {
diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index 1ccabd941b..4eb4d24088 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -2339,7 +2339,7 @@ static void qc_prep_fast_retrans(struct quic_enc_level *qel,
 	/* Skip the empty packet (they have already been retransmitted) */
 	while (node) {
 		pkt = eb64_entry(&node->node, struct quic_tx_packet, pn_node);
-		if (!LIST_ISEMPTY(&pkt->frms))
+		if (!LIST_ISEMPTY(&pkt->frms) && !(pkt->flags & QUIC_FL_TX_PACKET_COALESCED))
 			break;
 		node = eb64_next(node);
 	}
@@ -2395,7 +2395,7 @@ static void qc_prep_hdshk_fast_retrans(struct quic_conn *qc)
 	/* Skip the empty packet (they have already been retransmitted) */
 	while (node) {
 		pkt = eb64_entry(&node->node, struct quic_tx_packet, pn_node);
-		if (!LIST_ISEMPTY(&pkt->frms))
+		if (!LIST_ISEMPTY(&pkt->frms) && !(pkt->flags & QUIC_FL_TX_PACKET_COALESCED))
 			break;
 		node = eb64_next(node);
 	}
@@ -2961,8 +2961,10 @@ static int qc_prep_pkts(struct quic_conn *qc, struct qring *qr,
 		if (!first_pkt)
 			first_pkt = cur_pkt;
 		/* Attach the current one to the previous one */
-		if (prv_pkt)
+		if (prv_pkt) {
 			prv_pkt->next = cur_pkt;
+			cur_pkt->flags |= QUIC_FL_TX_PACKET_COALESCED;
+		}
 		/* Let's say we have to build a new dgram */
 		prv_pkt = NULL;
 		dglen += cur_pkt->len;