Allows QUIC connections to remain established even though the peer's

net/quic/quic_connection.h

Index: net/quic/quic_connection.h
diff --git a/net/quic/quic_connection.h b/net/quic/quic_connection.h
index 89affd3c4376ca24e0c1df3a6703ecbfa53b1bab..745cf85f2c73ac529dafb85de8304ff7b4178469 100644
--- a/net/quic/quic_connection.h
+++ b/net/quic/quic_connection.h
@@ -611,6 +611,11 @@ class NET_EXPORT_PRIVATE QuicConnection
   // Sets the ping alarm to the appropriate value, if any.
   void SetPingAlarm();
 
+  // On arrival of a new packet, checks to see if the socket addresses have
+  // changed since the last packet we saw on this connection.
+  void CheckForAddressMigration(const IPEndPoint& self_address,
+                                const IPEndPoint& peer_address);
+
   QuicFramer framer_;
   QuicConnectionHelperInterface* helper_;  // Not owned.
   QuicPacketWriter* writer_;  // Not owned.
@@ -623,6 +628,8 @@ class NET_EXPORT_PRIVATE QuicConnection
   // client.
   IPEndPoint self_address_;
   IPEndPoint peer_address_;
+  // Used to store latest peer port to possibly migrate to later.
+  int migrating_peer_port_;
 
   bool last_packet_revived_;  // True if the last packet was revived from FEC.
   size_t last_size_;  // Size of the last received packet.
@@ -734,9 +741,21 @@ class NET_EXPORT_PRIVATE QuicConnection
   // close.
   bool connected_;
 
-  // Set to true if the udp packet headers have a new self or peer address.
-  // This is checked later on validating a data or version negotiation packet.
-  bool address_migrating_;
+  // Set to true if the UDP packet headers have a new IP address for the peer.
+  // If true, do not perform connection migration.
+  bool peer_ip_changed_;
+
+  // Set to true if the UDP packet headers have a new port for the peer.
+  // If true, and the IP has not changed, then we can migrate the connection.
+  bool peer_port_changed_;
+
+  // Set to true if the UDP packet headers are addressed to a different IP.
+  // We do not support connection migration when the self IP changed.
+  bool self_ip_changed_;
+
+  // Set to true if the UDP packet headers are addressed to a different port.
+  // If true, and the IP has not changed, then we can migrate the connection.

[wtc, 2014/05/13 16:37:15]

IMPORTANT: this comment doesn't match the code in
QuicConnection::ProcessValidatedPacket(). To match the code, this comment should
say:

  We do not support connection migration when the self port changed.

[Robbie Shade, 2014/05/13 21:31:21]

Correct - this comment is wrong, make the change wtc suggests.

[ramant (doing other things), 2014/05/14 05:30:23]

Made this change in
https://codereview.chromium.org/286693003/diff/1/net/quic/quic_connection.h

Done.

+  bool self_port_changed_;
 
   // If non-empty this contains the set of versions received in a
   // version negotiation packet.