# HG changeset patch
# User Vladimir Homutov <vl@nginx.com>
# Date 1589799293 -10800
# Node ID e169cce912c7b089ab0c028881cdc394d17ea71f
# Parent  5ffb21c5c93d1fe11bb4855262a70cbed81c2a5a
Avoid retransmitting of packets with discarded keys.

Sections 4.10.1 and 4.10.2 of quic transport describe discarding of initial
and handshake keys.  Since the keys are discarded, we no longer need
to retransmit packets and corresponding queues should be emptied.

This patch removes previously added workaround that did not require
acknowledgement for initial packets, resulting in avoiding retransmission,
which is wrong because a packet could be lost and we have to retransmit it.

diff -r 5ffb21c5c93d -r e169cce912c7 src/event/ngx_event_quic.c
--- a/src/event/ngx_event_quic.c	Mon May 18 13:54:35 2020 +0300
+++ b/src/event/ngx_event_quic.c	Mon May 18 13:54:53 2020 +0300
@@ -1602,6 +1602,13 @@
         return NGX_ERROR;
     }
 
+    /*
+     * 4.10.1. The successful use of Handshake packets indicates
+     * that no more Initial packets need to be exchanged
+     */
+    ctx = ngx_quic_get_send_ctx(c->quic, ssl_encryption_initial);
+    ngx_quic_free_frames(c, &ctx->sent);
+
     return ngx_quic_payload_handler(c, pkt);
 }
 
@@ -2438,6 +2445,7 @@
     int                       sslerr;
     ssize_t                   n;
     ngx_ssl_conn_t           *ssl_conn;
+    ngx_quic_send_ctx_t      *ctx;
     ngx_quic_crypto_frame_t  *f;
 
     f = &frame->u.crypto;
@@ -2507,6 +2515,13 @@
         {
             return NGX_ERROR;
         }
+
+        /*
+         * 4.10.2 An endpoint MUST discard its handshake keys
+         * when the TLS handshake is confirmed
+         */
+        ctx = ngx_quic_get_send_ctx(c->quic, ssl_encryption_handshake);
+        ngx_quic_free_frames(c, &ctx->sent);
     }
 
     ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0,
@@ -3069,14 +3084,6 @@
         f->last = now;
     }
 
-    if (start->level == ssl_encryption_initial) {
-        /* ack will not be sent in initial packets due to initial keys being
-         * discarded when handshake start.
-         * Thus consider initial packets as non-ack-eliciting
-         */
-        pkt.need_ack = 0;
-    }
-
     out.len = p - out.data;
 
     while (out.len < 4) {