From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Tue, 6 Aug 2024 14:30:42 +0000 (+0200)
Subject: MINOR: quic: enforce ACK reception is handled in order
X-Git-Tag: v3.1-dev5~38
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b2282082dd163be8a083f505fa3c864d2d15e174;p=thirdparty%2Fhaproxy.git

MINOR: quic: enforce ACK reception is handled in order

Add a new BUG_ON() in qc-stream_desc_ack(). It ensures that
acknowledgement are always notify in-order. This is because out-of-order
ACKs cannot be handled by qc_stream_desc layer which does not support
gap in STREAM sent data.

Prior to this fix, out-of-order ACKs are simply ignored without any
error. This currently cannot happen thanks to careful
qc_stream_desc_ack() invokation. If this assumption is broken in the
future by inatteion, this would cause loss of ACK notification which
will prevent qc_stream_desc release.
---

diff --git a/src/quic_stream.c b/src/quic_stream.c
index 9741f8e710..6a470488e5 100644
--- a/src/quic_stream.c
+++ b/src/quic_stream.c
@@ -156,7 +156,10 @@ int qc_stream_desc_ack(struct qc_stream_desc **stream, size_t offset, size_t len
 	/* Cannot advertise FIN for an inferior data range. */
 	BUG_ON(fin && offset + len < s->ack_offset);
 
-	if (offset + len < s->ack_offset || offset > s->ack_offset)
+	/* No support now for out-of-order ACK reporting. */
+	BUG_ON(offset > s->ack_offset);
+
+	if (offset + len < s->ack_offset)
 		return 0;
 
 	diff = offset + len - s->ack_offset;