From: Frédéric Lécaille <flecaille@haproxy.com>
Date: Tue, 21 Feb 2023 15:44:05 +0000 (+0100)
Subject: BUG/MINOR: quic: Ensure to be able to build datagrams to be retransmitted
X-Git-Tag: v2.8-dev5~40
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d30a04a4bb4522d6ead55f2de788d9195d16df89;p=thirdparty%2Fhaproxy.git

BUG/MINOR: quic: Ensure to be able to build datagrams to be retransmitted

When retransmitting datagrams with two coalesced packets inside, the second
packet was not taken into consideration when checking there is enough space
into the network for the datagram, especially when limited by the anti-amplification.

Must be backported to 2.6 and 2.7.
---

diff --git a/src/quic_conn.c b/src/quic_conn.c
index d8bcb76f91..463b897515 100644
--- a/src/quic_conn.c
+++ b/src/quic_conn.c
@@ -2554,7 +2554,7 @@ static void qc_prep_fast_retrans(struct quic_conn *qc,
 	struct eb64_node *node;
 	struct quic_tx_packet *pkt;
 
-	TRACE_ENTER(QUIC_EV_CONN_PRSAFRM, qc);
+	TRACE_ENTER(QUIC_EV_CONN_SPPKTS, qc);
 
 	BUG_ON(frms1 == frms2);
 
@@ -2613,7 +2613,7 @@ static void qc_prep_hdshk_fast_retrans(struct quic_conn *qc,
 	struct quic_tx_packet *pkt;
 	struct list *tmp = &itmp;
 
-	TRACE_ENTER(QUIC_EV_CONN_PRSAFRM, qc);
+	TRACE_ENTER(QUIC_EV_CONN_SPPKTS, qc);
  start:
 	pkt = NULL;
 	pkts = &qel->pktns->tx.pkts;
@@ -2635,10 +2635,16 @@ static void qc_prep_hdshk_fast_retrans(struct quic_conn *qc,
 	/* When building a packet from another one, the field which may increase the
 	 * packet size is the packet number. And the maximum increase is 4 bytes.
 	 */
-	if (!quic_peer_validated_addr(qc) && qc_is_listener(qc) &&
-	    pkt->len + 4 > 3 * qc->rx.bytes - qc->tx.prep_bytes) {
-		TRACE_PROTO("anti-amplification limit would be reached", QUIC_EV_CONN_PRSAFRM, qc);
-		goto end;
+	if (!quic_peer_validated_addr(qc) && qc_is_listener(qc)) {
+		size_t dglen = pkt->len + 4;
+
+		dglen += pkt->next ? pkt->next->len + 4 : 0;
+		if (dglen > 3 * qc->rx.bytes - qc->tx.prep_bytes) {
+			TRACE_PROTO("anti-amplification limit would be reached", QUIC_EV_CONN_SPPKTS, qc, pkt);
+			if (pkt->next)
+				TRACE_PROTO("anti-amplification limit would be reached", QUIC_EV_CONN_SPPKTS, qc, pkt->next);
+			goto end;
+		}
 	}
 
 	qel->pktns->tx.pto_probe += 1;
@@ -2652,7 +2658,7 @@ static void qc_prep_hdshk_fast_retrans(struct quic_conn *qc,
 			pkt = pkt->next;
 			tmp = &htmp;
 			hqel->pktns->tx.pto_probe += 1;
-			TRACE_DEVEL("looping for next packet", QUIC_EV_CONN_PRSAFRM, qc);
+			TRACE_DEVEL("looping for next packet", QUIC_EV_CONN_SPPKTS, qc);
 			goto requeue;
 		}
 	}
@@ -2661,7 +2667,7 @@ static void qc_prep_hdshk_fast_retrans(struct quic_conn *qc,
 	LIST_SPLICE(ifrms, &itmp);
 	LIST_SPLICE(hfrms, &htmp);
 
-	TRACE_LEAVE(QUIC_EV_CONN_PRSAFRM, qc);
+	TRACE_LEAVE(QUIC_EV_CONN_SPPKTS, qc);
 }
 
 static void qc_cc_err_count_inc(struct quic_conn *qc, struct quic_frame *frm)
@@ -3329,7 +3335,7 @@ static int qc_prep_pkts(struct quic_conn *qc, struct buffer *buf,
 		 */
 		if (pkt_type == QUIC_PACKET_TYPE_INITIAL && !LIST_ISEMPTY(tel_frms)) {
 			if (end - pos < QUIC_INITIAL_PACKET_MINLEN) {
-				TRACE_PROTO("No more enough room to build an Initial packets",
+				TRACE_PROTO("No more enough room to build an Initial packet",
 				            QUIC_EV_CONN_PHPKTS, qc);
 				goto out;
 			}