# HG changeset patch
# User Roman Arutyunyan <arut@nginx.com>
# Date 1627563697 -10800
# Node ID c35b255d80dc70f111efa13cc8806c292768ab57
# Parent  59d2d47ad3c6b4e9aa8167861855fc75b79ac8d2
HTTP/3: close connection on keepalive_requests * 2.

After receiving GOAWAY, client is not supposed to create new streams.  However,
until client reads this frame, we allow it to create new streams, which are
gracefully rejected.  To prevent client from abusing this algorithm, a new
limit is introduced.  Upon reaching keepalive_requests * 2, server now closes
the entire QUIC connection claiming excessive load.

diff --git a/src/http/v3/ngx_http_v3_request.c b/src/http/v3/ngx_http_v3_request.c
--- a/src/http/v3/ngx_http_v3_request.c
+++ b/src/http/v3/ngx_http_v3_request.c
@@ -81,6 +81,15 @@ ngx_http_v3_init(ngx_connection_t *c)
 
     clcf = ngx_http_get_module_loc_conf(hc->conf_ctx, ngx_http_core_module);
 
+    n = c->quic->id >> 2;
+
+    if (n >= clcf->keepalive_requests * 2) {
+        ngx_http_v3_finalize_connection(c, NGX_HTTP_V3_ERR_EXCESSIVE_LOAD,
+                                        "too many requests per connection");
+        ngx_http_close_connection(c);
+        return;
+    }
+
     h3c = ngx_http_v3_get_session(c);
 
     if (h3c->goaway) {
@@ -89,8 +98,6 @@ ngx_http_v3_init(ngx_connection_t *c)
         return;
     }
 
-    n = c->quic->id >> 2;
-
     if (n + 1 == clcf->keepalive_requests
         || ngx_current_msec - c->quic->parent->start_time
            > clcf->keepalive_time)