From: Amaury Denoyelle <adenoyelle@haproxy.com>
Date: Thu, 21 Dec 2023 10:15:19 +0000 (+0100)
Subject: BUG/MINOR: mux-quic: disable fast-fwd if connection on error
X-Git-Tag: v3.0-dev1~40
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=19f4f4d890bc28bbe4b850e1ced9be399f59fafb;p=thirdparty%2Fhaproxy.git

BUG/MINOR: mux-quic: disable fast-fwd if connection on error

Add a check on nego_ff to ensure connection is not on error. If this is
the case, fast-forward is disable to prevent unnecessary sending. If
snd_buf is latter called, stconn will be notified of the error to
interrupt the stream.

This check is necessary to ensure snd_buf and nego_ff are consistent.
Note that previously, if fast-forward was conducted even on connection
error, no sending would occur as qcc_io_send() also check these flags.
However, there is a risk that stconn is never notified of the error
status, thus it is considered as a bug.

Its impact is minimal for now as fast-forward is disable by default on
QUIC. By fixing it, it should be possible to reactive it soon.

This should be backported up to 2.9.
---

diff --git a/src/mux_quic.c b/src/mux_quic.c
index 21b1cdec79..1ad4a07de1 100644
--- a/src/mux_quic.c
+++ b/src/mux_quic.c
@@ -2868,6 +2868,15 @@ static size_t qmux_strm_nego_ff(struct stconn *sc, struct buffer *input,
 		goto end;
 	}
 
+	if (qcs->qcc->flags & (QC_CF_ERR_CONN|QC_CF_ERRL)) {
+		/* Disable fast-forward if connection is on error. Eventually,
+		 * error will be reported to stream-conn if snd_buf is invoked.
+		 */
+		TRACE_DEVEL("connection in error", QMUX_EV_STRM_SEND, qcs->qcc->conn, qcs);
+		qcs->sd->iobuf.flags |= IOBUF_FL_NO_FF;
+		goto end;
+	}
+
 	/* Alawys disable splicing */
 	qcs->sd->iobuf.flags |= IOBUF_FL_NO_SPLICING;