commit 30ab6db4b50370446740ebfb6cde85a104872695
author dschinazi <dschinazi@google.com> Tue Aug 13 14:43:32 2019 -0700
committer Copybara-Service <copybara-worker@google.com> Thu Aug 15 09:07:10 2019 -0700
tree e6f5201d33c5e0c3ee4c3e3e1bd91d55a32dcc7b
parent 7591c284c4ded9f872ab1cb57b835b92742ce075

Send correct version negotiation to prober

QuicDispatcher::MaybeDispatchPacket was incorrectly computing the value of use_length_prefix instead of using the one from packet_info. This CL also adds regression tests to prevent this issue from coming back.

gfe-relnote: change length-prefix of version negotiation, protected by gfe2_reloadable_flag_quic_use_length_prefix_from_packet_info
PiperOrigin-RevId: 263219043
Change-Id: I14fc1dbcfffb1dd0cd79c03c90cc982cdab96d9c

quic/core/quic_dispatcher.cc

diff --git a/quic/core/quic_dispatcher.cc b/quic/core/quic_dispatcher.cc
index c944862..4c73dfe 100644
--- a/quic/core/quic_dispatcher.cc
+++ b/quic/core/quic_dispatcher.cc
@@ -431,12 +431,20 @@
         // packet and stop processing the current packet.
         QuicConnectionId client_connection_id =
             packet_info.source_connection_id;
+        bool use_length_prefix = packet_info.use_length_prefix;
+        if (!GetQuicReloadableFlag(quic_use_length_prefix_from_packet_info)) {
+          use_length_prefix = packet_info.form != GOOGLE_QUIC_PACKET &&
+                              !QuicVersionLabelUses4BitConnectionIdLength(
+                                  packet_info.version_label);
+        } else {
+          QUIC_RELOADABLE_FLAG_COUNT(quic_use_length_prefix_from_packet_info);
+          // TODO(dschinazi) remove the client-side workaround in
+          // QuicFramer::ParseServerVersionNegotiationProbeResponse
+          // when quic_use_length_prefix_from_packet_info is deprecated.
+        }
         time_wait_list_manager()->SendVersionNegotiationPacket(
             server_connection_id, client_connection_id,
-            packet_info.form != GOOGLE_QUIC_PACKET,
-            packet_info.form != GOOGLE_QUIC_PACKET &&
-                !QuicVersionLabelUses4BitConnectionIdLength(
-                    packet_info.version_label),
+            packet_info.form != GOOGLE_QUIC_PACKET, use_length_prefix,
             GetSupportedVersions(), packet_info.self_address,
             packet_info.peer_address, GetPerPacketContext());
       }