From 167e38e0e0296e899aa894d2f3db5ba2a0c68cb5 Mon Sep 17 00:00:00 2001
From: Frederic Lecaille <flecaille@haproxy.com>
Date: Tue, 13 Feb 2024 21:24:40 +0100
Subject: [PATCH] MINOR: quic: Add a counter for reordered packets

A packet is considered as reordered when it is detected as lost because its packet
number is above the largest acknowledeged packet number by at least the
packet reordering threshold value.

Add ->nb_reordered_pkt new quic_loss struct member at the same location that
the number of lost packets to count such packets.

Should be backported to 2.6.
---
 include/haproxy/quic_loss-t.h | 1 +
 include/haproxy/quic_loss.h   | 1 +
 src/quic_cli.c                | 4 ++--
 src/quic_loss.c               | 9 +++++++--
 4 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/include/haproxy/quic_loss-t.h b/include/haproxy/quic_loss-t.h
index d1fea9f7e..0f07ddc00 100644
--- a/include/haproxy/quic_loss-t.h
+++ b/include/haproxy/quic_loss-t.h
@@ -55,6 +55,7 @@ struct quic_loss {
 	/* Number of NACKed sent PTO. */
 	unsigned int pto_count;
 	unsigned long nb_lost_pkt;
+	unsigned long nb_reordered_pkt;
 };
 
 #endif /* USE_QUIC */
diff --git a/include/haproxy/quic_loss.h b/include/haproxy/quic_loss.h
index d2a0e776b..fc713ca07 100644
--- a/include/haproxy/quic_loss.h
+++ b/include/haproxy/quic_loss.h
@@ -40,6 +40,7 @@ static inline void quic_loss_init(struct quic_loss *ql)
 	ql->rtt_min = 0;
 	ql->pto_count = 0;
 	ql->nb_lost_pkt = 0;
+	ql->nb_reordered_pkt = 0;
 }
 
 /* Return 1 if a persistent congestion is observed for a list of
diff --git a/src/quic_cli.c b/src/quic_cli.c
index 07a32f6cb..56301fa84 100644
--- a/src/quic_cli.c
+++ b/src/quic_cli.c
@@ -204,10 +204,10 @@ static void dump_quic_full(struct show_quic_ctx *ctx, struct quic_conn *qc)
 	}
 
 	chunk_appendf(&trash, "  srtt=%-4u rttvar=%-4u rttmin=%-4u ptoc=%-4u cwnd=%-6llu"
-	                      " mcwnd=%-6llu sentpkts=%-6llu lostpkts=%-6llu\n",
+	                      " mcwnd=%-6llu sentpkts=%-6llu lostpkts=%-6llu\n reorderedpkts=%-6llu",
 	              qc->path->loss.srtt, qc->path->loss.rtt_var,
 	              qc->path->loss.rtt_min, qc->path->loss.pto_count, (ullong)qc->path->cwnd,
-	              (ullong)qc->path->mcwnd, (ullong)qc->cntrs.sent_pkt, (ullong)qc->path->loss.nb_lost_pkt);
+	              (ullong)qc->path->mcwnd, (ullong)qc->cntrs.sent_pkt, (ullong)qc->path->loss.nb_lost_pkt, (ullong)qc->path->loss.nb_reordered_pkt);
 
 	if (qc->cntrs.dropped_pkt) {
 		chunk_appendf(&trash, " droppkts=%-6llu", qc->cntrs.dropped_pkt);
diff --git a/src/quic_loss.c b/src/quic_loss.c
index fa0e4ba57..fd9568a50 100644
--- a/src/quic_loss.c
+++ b/src/quic_loss.c
@@ -197,6 +197,7 @@ void qc_packet_loss_lookup(struct quic_pktns *pktns, struct quic_conn *qc,
 		struct quic_tx_packet *pkt;
 		int64_t largest_acked_pn;
 		unsigned int loss_time_limit, time_sent;
+		int reordered;
 
 		pkt = eb64_entry(&node->node, struct quic_tx_packet, pn_node);
 		largest_acked_pn = pktns->rx.largest_acked_pn;
@@ -206,8 +207,12 @@ void qc_packet_loss_lookup(struct quic_pktns *pktns, struct quic_conn *qc,
 
 		time_sent = pkt->time_sent;
 		loss_time_limit = tick_add(time_sent, loss_delay);
-		if (tick_is_le(loss_time_limit, now_ms) ||
-			(int64_t)largest_acked_pn >= pkt->pn_node.key + pktthresh) {
+
+		reordered = (int64_t)largest_acked_pn >= pkt->pn_node.key + pktthresh;
+		if (reordered)
+			ql->nb_reordered_pkt++;
+
+		if (tick_is_le(loss_time_limit, now_ms) || reordered) {
 			eb64_delete(&pkt->pn_node);
 			LIST_APPEND(lost_pkts, &pkt->list);
 			ql->nb_lost_pkt++;