commit c65d1d143ba830d14393a29a8234a678e8c68a17
author QUICHE team <quiche-dev@google.com> Tue Mar 19 20:58:04 2019 -0700
committer Copybara-Service <copybara-worker@google.com> Tue Mar 19 20:58:34 2019 -0700
tree 196e59643542e457cbf602be5bdc3898d7f0ac8e
parent 2d18797ec691cd95d9f08271840d024a0e7a3311

Allow QUIC server to replace connection IDs

This CL changes the QuicDispatcher to have it replace the connection ID provided by the client if its length differs from what the dispatcher was configured with. It also changes QuicConnection on the client side to accept connection ID changes coming from the server, and replace its own connection ID to match what the server expects on outgoing packets. This checks VariableLengthConnectionIdAllowedForVersion() so it only impacts v99.

gfe-relnote: v99-only change, not flag protected
PiperOrigin-RevId: 239328650
Change-Id: I21ee0c0ca74c7624823c38a72f323ae6491e21e6

quic/core/quic_connection.cc

diff --git a/quic/core/quic_connection.cc b/quic/core/quic_connection.cc
index 17752a6..dcea61d 100644
--- a/quic/core/quic_connection.cc
+++ b/quic/core/quic_connection.cc
@@ -21,6 +21,7 @@
 #include "net/third_party/quiche/src/quic/core/proto/cached_network_parameters.pb.h"
 #include "net/third_party/quiche/src/quic/core/quic_bandwidth.h"
 #include "net/third_party/quiche/src/quic/core/quic_config.h"
+#include "net/third_party/quiche/src/quic/core/quic_connection_id.h"
 #include "net/third_party/quiche/src/quic/core/quic_packet_generator.h"
 #include "net/third_party/quiche/src/quic/core/quic_pending_retransmission.h"
 #include "net/third_party/quiche/src/quic/core/quic_types.h"
@@ -206,6 +207,17 @@
   QuicConnection* connection_;
 };
 
+// Whether this incoming packet is allowed to replace our connection ID.
+bool PacketCanReplaceConnectionId(const QuicPacketHeader& header,
+                                  Perspective perspective) {
+  return perspective == Perspective::IS_CLIENT &&
+         header.form == IETF_QUIC_LONG_HEADER_PACKET &&
+         QuicUtils::VariableLengthConnectionIdAllowedForVersion(
+             header.version.transport_version) &&
+         (header.long_packet_type == INITIAL ||
+          header.long_packet_type == RETRY);
+}
+
 }  // namespace
 
 #define ENDPOINT \
@@ -719,9 +731,34 @@
   RetransmitUnackedPackets(ALL_UNACKED_RETRANSMISSION);
 }
 
+bool QuicConnection::HasIncomingConnectionId(QuicConnectionId connection_id) {
+  for (QuicConnectionId const& incoming_connection_id :
+       incoming_connection_ids_) {
+    if (incoming_connection_id == connection_id) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void QuicConnection::AddIncomingConnectionId(QuicConnectionId connection_id) {
+  if (HasIncomingConnectionId(connection_id)) {
+    return;
+  }
+  incoming_connection_ids_.push_back(connection_id);
+}
+
 bool QuicConnection::OnUnauthenticatedPublicHeader(
     const QuicPacketHeader& header) {
-  if (header.destination_connection_id == connection_id_) {
+  if (header.destination_connection_id == connection_id_ ||
+      HasIncomingConnectionId(header.destination_connection_id)) {
+    return true;
+  }
+
+  if (PacketCanReplaceConnectionId(header, perspective_)) {
+    QUIC_DLOG(INFO) << ENDPOINT << "Accepting packet with new connection ID "
+                    << header.destination_connection_id << " instead of "
+                    << connection_id_;
     return true;
   }
 
@@ -748,7 +785,9 @@
   // Check that any public reset packet with a different connection ID that was
   // routed to this QuicConnection has been redirected before control reaches
   // here.
-  DCHECK_EQ(connection_id_, header.destination_connection_id);
+  DCHECK(header.destination_connection_id == connection_id_ ||
+         HasIncomingConnectionId(header.destination_connection_id) ||
+         PacketCanReplaceConnectionId(header, perspective_));
 
   if (!packet_generator_.IsPendingPacketEmpty()) {
     // Incoming packets may change a queued ACK frame.
@@ -1947,6 +1986,14 @@
     self_address_ = last_packet_destination_address_;
   }
 
+  if (PacketCanReplaceConnectionId(header, perspective_) &&
+      connection_id_ != header.source_connection_id) {
+    QUIC_DLOG(INFO) << ENDPOINT << "Replacing connection ID " << connection_id_
+                    << " with " << header.source_connection_id;
+    connection_id_ = header.source_connection_id;
+    packet_generator_.SetConnectionId(connection_id_);
+  }
+
   if (!ValidateReceivedPacketNumber(header.packet_number)) {
     return false;
   }