HTTP/2: relaxed PRIORITY frames limit.
Firefox uses several idle streams for PRIORITY frames[1], and
"http2_max_concurrent_streams 1;" results in "client sent too many
PRIORITY frames" errors when a connection is established by Firefox.
Fix is to relax the PRIORITY frames limit to use at least 100 as
the initial value (which is the recommended by the HTTP/2 protocol
minimum limit on the number of concurrent streams, so it is not
unreasonable for clients to assume that similar number of idle streams
can be used for prioritization).
[1] https://hg.mozilla.org/mozilla-central/file/32a9e6e145d6e3071c3993a20bb603a2f388722b/netwerk/protocol/http/Http2Stream.cpp#l1270
diff --git a/src/http/v2/ngx_http_v2.c b/src/http/v2/ngx_http_v2.c
index 8563205..69a94b6 100644
--- a/src/http/v2/ngx_http_v2.c
+++ b/src/http/v2/ngx_http_v2.c
@@ -277,7 +277,7 @@
h2scf = ngx_http_get_module_srv_conf(hc->conf_ctx, ngx_http_v2_module);
h2c->concurrent_pushes = h2scf->concurrent_pushes;
- h2c->priority_limit = h2scf->concurrent_streams;
+ h2c->priority_limit = ngx_max(h2scf->concurrent_streams, 100);
h2c->pool = ngx_create_pool(h2scf->pool_size, h2c->connection->log);
if (h2c->pool == NULL) {
