# HG changeset patch
# User Vladimir Homutov <vl@nginx.com>
# Date 1602751021 -10800
# Node ID 02ee77f8d53df0f2a799dfb0b5c169968ec71ee1
# Parent  474706351c0951b466f574e9abaad2f95cb068f8
QUIC: account packet header length in amplification limit.

Header length calculation is adjusted to account real connection id lengths
instead of worst case.

diff --git a/src/event/ngx_event_quic.c b/src/event/ngx_event_quic.c
--- a/src/event/ngx_event_quic.c
+++ b/src/event/ngx_event_quic.c
@@ -3757,6 +3757,7 @@ ngx_quic_output_frames(ngx_connection_t 
     hlen = (f->level == ssl_encryption_application) ? NGX_QUIC_MAX_SHORT_HEADER
                                                     : NGX_QUIC_MAX_LONG_HEADER;
     hlen += EVP_GCM_TLS_TAG_LEN;
+    hlen -= NGX_QUIC_MAX_CID_LEN - qc->scid.len;
 
     do {
         len = 0;
@@ -3786,7 +3787,7 @@ ngx_quic_output_frames(ngx_connection_t 
                  * send more than three times the data it receives;
                  */
 
-                if (((c->sent + len + f->len) / 3) > qc->received) {
+                if (((c->sent + hlen + len + f->len) / 3) > qc->received) {
                     ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
                                    "quic hit amplification limit"
                                    " received %uz sent %O",
diff --git a/src/event/ngx_event_quic.h b/src/event/ngx_event_quic.h
--- a/src/event/ngx_event_quic.h
+++ b/src/event/ngx_event_quic.h
@@ -54,7 +54,8 @@
 
 #define NGX_QUIC_STREAM_BUFSIZE              65536
 
-#define NGX_QUIC_SERVER_CID_LEN              20
+#define NGX_QUIC_MAX_CID_LEN                 20
+#define NGX_QUIC_SERVER_CID_LEN              NGX_QUIC_MAX_CID_LEN
 
 #define NGX_QUIC_SR_TOKEN_LEN                16