From: Willy Tarreau <w@1wt.eu>
Date: Mon, 28 Jan 2019 05:40:19 +0000 (+0100)
Subject: BUG/MINOR: mux-h2: do not report available outgoing streams after GOAWAY
X-Git-Tag: v2.0-dev1~148
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6afec46ba327ef4de202271397f61ef4cf8a0d7d;p=thirdparty%2Fhaproxy.git

BUG/MINOR: mux-h2: do not report available outgoing streams after GOAWAY

The calculation of available outgoing H2 streams was improved by commit
d64a3ebe6 ("BUG/MINOR: mux-h2: always check the stream ID limit in
h2_avail_streams()"), but it still is incorrect because RFC7540#6.8
specifically forbids the creation of new streams after a GOAWAY frame
was received. Thus we must not mark the connection as available anymore
in order to be able to handle a graceful shutdown.

This needs to be backported to 1.9.
---

diff --git a/src/mux_h2.c b/src/mux_h2.c
index 2972ca296b..90895e288c 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -415,6 +415,12 @@ static int h2_avail_streams(struct connection *conn)
 	struct h2c *h2c = conn->ctx;
 	int ret1, ret2;
 
+	/* RFC7540#6.8: Receivers of a GOAWAY frame MUST NOT open additional
+	 * streams on the connection.
+	 */
+	if (h2c->last_sid >= 0)
+		return 0;
+
 	/* XXX Should use the negociated max concurrent stream nb instead of the conf value */
 	ret1 = h2_settings_max_concurrent_streams - h2c->nb_streams;