From: Willy Tarreau <w@1wt.eu>
Date: Wed, 23 Jan 2019 09:25:10 +0000 (+0100)
Subject: MINOR: mux-h2: always consider a server's max-reuse parameter
X-Git-Tag: v2.0-dev1~158
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e9634bdc224c9c56854766647207e4f1b000f713;p=thirdparty%2Fhaproxy.git

MINOR: mux-h2: always consider a server's max-reuse parameter

This parameter allows to limit the number of successive requests sent
on a connection. Let's compare it to the number of streams already sent
on the connection to decide if the connection may still appear in the
idle list or not. This may be used to help certain servers work around
resource leaks, and also helps dealing with the issue of the GOAWAY in
flight which requires to set a usage limit on the client to be reliable.

This must be backported to 1.9.
---

diff --git a/src/mux_h2.c b/src/mux_h2.c
index 21796c3563..5754f79c29 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -119,7 +119,7 @@ struct h2c {
 	unsigned int nb_streams;  /* number of streams in the tree */
 	unsigned int nb_cs;       /* number of attached conn_streams */
 	unsigned int nb_reserved; /* number of reserved streams */
-	/* 32 bit hole here */
+	unsigned int stream_cnt;  /* total number of streams seen */
 	struct proxy *proxy; /* the proxy this connection was created for */
 	struct task *task;  /* timeout management task */
 	struct eb_root streams_by_id; /* all active streams by their ID */
@@ -410,6 +410,7 @@ static inline int h2_streams_left(const struct h2c *h2c)
 /* returns the number of concurrent streams available on the connection */
 static int h2_avail_streams(struct connection *conn)
 {
+	struct server *srv = objt_server(conn->target);
 	struct h2c *h2c = conn->ctx;
 	int ret1, ret2;
 
@@ -418,7 +419,12 @@ static int h2_avail_streams(struct connection *conn)
 
 	/* we must also consider the limit imposed by stream IDs */
 	ret2 = h2_streams_left(h2c);
-	return MIN(ret1, ret2);
+	ret1 = MIN(ret1, ret2);
+	if (ret1 && srv && srv->max_reuse >= 0) {
+		ret2 = h2c->stream_cnt <= srv->max_reuse ? srv->max_reuse - h2c->stream_cnt + 1: 0;
+		ret1 = MIN(ret1, ret2);
+	}
+	return ret1;
 }
 
 static int h2_max_streams(struct connection *conn)
@@ -492,10 +498,12 @@ static int h2_init(struct connection *conn, struct proxy *prx, struct session *s
 	h2c->nb_streams = 0;
 	h2c->nb_cs = 0;
 	h2c->nb_reserved = 0;
+	h2c->stream_cnt = 0;
 
 	h2c->dbuf = BUF_NULL;
 	h2c->dsi = -1;
 	h2c->msi = -1;
+
 	h2c->last_sid = -1;
 
 	h2c->mbuf = BUF_NULL;
@@ -883,6 +891,7 @@ static struct h2s *h2s_new(struct h2c *h2c, int id)
 
 	eb32_insert(&h2c->streams_by_id, &h2s->by_id);
 	h2c->nb_streams++;
+	h2c->stream_cnt++;
 
 	return h2s;