From: Frédéric Lécaille <flecaille@haproxy.com>
Date: Wed, 24 Aug 2022 16:59:23 +0000 (+0200)
Subject: CLEANUP: quic: Remove a useless check in qc_lstnr_pkt_rcv()
X-Git-Tag: v2.7-dev5~57
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=560ddfa0035cd747c2f87d70aae2fe897dfef226;p=thirdparty%2Fhaproxy.git

CLEANUP: quic: Remove a useless check in qc_lstnr_pkt_rcv()

This function parses the QUIC packet from a UDP datagram. It was originally
supposed to be run by several thread. Here we remove a section of code
where the current thread checks there is not another thread which has already
inserted the new quic_conn it is trying to insert in the connections tree.

Must be backported to 2.6 to ease the future backports to come.
---

diff --git a/src/xprt_quic.c b/src/xprt_quic.c
index 2dbb4cba07..ffa2cba1fa 100644
--- a/src/xprt_quic.c
+++ b/src/xprt_quic.c
@@ -5785,7 +5785,7 @@ static void qc_lstnr_pkt_rcv(unsigned char *buf, const unsigned char *end,
                              struct quic_dgram *dgram, struct list **tasklist_head)
 {
 	unsigned char *beg, *payload;
-	struct quic_conn *qc, *qc_to_purge = NULL;
+	struct quic_conn *qc;
 	struct listener *l;
 	struct proxy *prx;
 	struct quic_counters *prx_counters;
@@ -5976,7 +5976,6 @@ static void qc_lstnr_pkt_rcv(unsigned char *buf, const unsigned char *end,
 		}
 		if (!qc) {
 			int ipv4;
-			struct ebmb_node *n = NULL;
 
 			if (pkt->type != QUIC_PACKET_TYPE_INITIAL) {
 				TRACE_PROTO("Non Initial packet", QUIC_EV_CONN_LPKT, NULL, NULL, NULL, qv);
@@ -6019,31 +6018,11 @@ static void qc_lstnr_pkt_rcv(unsigned char *buf, const unsigned char *end,
 
 			HA_ATOMIC_INC(&prx_counters->half_open_conn);
 			/* Insert the DCID the QUIC client has chosen (only for listeners) */
-			n = ebmb_insert(&quic_dghdlrs[tid].odcids, &qc->odcid_node,
-			                qc->odcid.len + qc->odcid.addrlen);
-
-			/* If the insertion failed, it means that another
-			 * thread has already allocated a QUIC connection for
-			 * the same CID. Liberate our allocated connection.
-			 */
-			if (unlikely(n != &qc->odcid_node)) {
-				qc_to_purge = qc;
-
-				qc = ebmb_entry(n, struct quic_conn, odcid_node);
-				pkt->qc = qc;
-			}
-
-			if (likely(!qc_to_purge)) {
-				/* Enqueue this packet. */
-				pkt->qc = qc;
-			}
-			else {
-				quic_conn_release(qc_to_purge);
-			}
-		}
-		else {
-			pkt->qc = qc;
+			ebmb_insert(&quic_dghdlrs[tid].odcids, &qc->odcid_node,
+			            qc->odcid.len + qc->odcid.addrlen);
 		}
+
+		pkt->qc = qc;
 	}
 	else {
 		TRACE_PROTO("short header packet received", QUIC_EV_CONN_LPKT, qc);