BUG/MINOR: mux-h2: refuse to allocate a stream with too high an ID
One of the reasons for the excessive number of aborted requests when a
server sets a limit on the highest stream ID is that we don't check
this limit while allocating a new stream.
This patch does this at two locations :
- when a backend stream is allocated, we verify that there are still
IDs left ;
- when the ID is assigned, we verify that it's not higher than the
advertised limit.
This should be backported to 1.9.
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 57bf469..21796c3 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -547,7 +547,8 @@
static inline int32_t h2c_get_next_sid(const struct h2c *h2c)
{
int32_t id = (h2c->max_id + 1) | 1;
- if (id & 0x80000000U)
+
+ if ((id & 0x80000000U) || (h2c->last_sid >= 0 && id > h2c->last_sid))
id = -1;
return id;
}
@@ -954,6 +955,9 @@
if (h2c->nb_streams >= h2_settings_max_concurrent_streams)
goto out;
+ if (h2_streams_left(h2c) < 1)
+ goto out;
+
/* Defer choosing the ID until we send the first message to create the stream */
h2s = h2s_new(h2c, 0);
if (!h2s)