Deprecates check_peer_address_change_after_decryption.

net/quic/quic_connection.cc

Index: net/quic/quic_connection.cc
diff --git a/net/quic/quic_connection.cc b/net/quic/quic_connection.cc
index 3b8765259f6d2e1ab62698dc9e13fa2e0c0015db..31603b76a410e229bb422d94212e4ec579b11525 100644
--- a/net/quic/quic_connection.cc
+++ b/net/quic/quic_connection.cc
@@ -223,7 +223,6 @@ QuicConnection::QuicConnection(QuicConnectionId connection_id,
       random_generator_(helper->GetRandomGenerator()),
       connection_id_(connection_id),
       peer_address_(address),
-      migrating_peer_port_(0),
       last_packet_decrypted_(false),
       last_size_(0),
       current_packet_data_(nullptr),
@@ -282,10 +281,6 @@ QuicConnection::QuicConnection(QuicConnectionId connection_id,
       version_negotiation_state_(START_NEGOTIATION),
       perspective_(perspective),
       connected_(true),
-      peer_ip_changed_(false),
-      peer_port_changed_(false),
-      self_ip_changed_(false),
-      self_port_changed_(false),
       can_truncate_connection_ids_(true),
       mtu_discovery_target_(0),
       mtu_probe_count_(0),
@@ -1217,17 +1212,13 @@ void QuicConnection::ProcessUdpPacket(const IPEndPoint& self_address,
   last_size_ = packet.length();
   current_packet_data_ = packet.data();
 
-  if (FLAGS_check_peer_address_change_after_decryption) {
-    last_packet_destination_address_ = self_address;
-    last_packet_source_address_ = peer_address;
-    if (!IsInitializedIPEndPoint(self_address_)) {
-      self_address_ = last_packet_destination_address_;
-    }
-    if (!IsInitializedIPEndPoint(peer_address_)) {
-      peer_address_ = last_packet_source_address_;
-    }
-  } else {
-    CheckForAddressMigration(self_address, peer_address);
+  last_packet_destination_address_ = self_address;
+  last_packet_source_address_ = peer_address;
+  if (!IsInitializedIPEndPoint(self_address_)) {
+    self_address_ = last_packet_destination_address_;
+  }
+  if (!IsInitializedIPEndPoint(peer_address_)) {
+    peer_address_ = last_packet_source_address_;
   }
 
   stats_.bytes_received += packet.length();
@@ -1258,35 +1249,6 @@ void QuicConnection::ProcessUdpPacket(const IPEndPoint& self_address,
   current_packet_data_ = nullptr;
 }
 
-void QuicConnection::CheckForAddressMigration(const IPEndPoint& self_address,
-                                              const IPEndPoint& peer_address) {
-  peer_ip_changed_ = false;
-  peer_port_changed_ = false;
-  self_ip_changed_ = false;
-  self_port_changed_ = false;
-
-  if (peer_address_.address().empty()) {
-    peer_address_ = peer_address;
-  }
-  if (self_address_.address().empty()) {
-    self_address_ = self_address;
-  }
-
-  if (!peer_address.address().empty() && !peer_address_.address().empty()) {
-    peer_ip_changed_ = (peer_address.address() != peer_address_.address());
-    peer_port_changed_ = (peer_address.port() != peer_address_.port());
-
-    // Store in case we want to migrate connection in ProcessValidatedPacket.
-    migrating_peer_ip_ = peer_address.address();
-    migrating_peer_port_ = peer_address.port();
-  }
-
-  if (!self_address.address().empty() && !self_address_.address().empty()) {
-    self_ip_changed_ = (self_address.address() != self_address_.address());
-    self_port_changed_ = (self_address.port() != self_address_.port());
-  }
-}
-
 void QuicConnection::OnCanWrite() {
   DCHECK(!writer_->IsWriteBlocked());
 
@@ -1337,24 +1299,14 @@ bool QuicConnection::ProcessValidatedPacket(const QuicPacketHeader& header) {
     return false;
   }
 
-  if (FLAGS_check_peer_address_change_after_decryption) {
-    if (perspective_ == Perspective::IS_SERVER &&
-        IsInitializedIPEndPoint(self_address_) &&
-        IsInitializedIPEndPoint(last_packet_destination_address_) &&
-        (!(self_address_ == last_packet_destination_address_))) {
-      SendConnectionCloseWithDetails(
-          QUIC_ERROR_MIGRATING_ADDRESS,
-          "Self address migration is not supported at the server.");
-      return false;
-    }
-  } else {
-    if (perspective_ == Perspective::IS_SERVER &&
-        (self_ip_changed_ || self_port_changed_)) {
-      SendConnectionCloseWithDetails(
-          QUIC_ERROR_MIGRATING_ADDRESS,
-          "Self address migration is not supported at the server.");
-      return false;
-    }
+  if (perspective_ == Perspective::IS_SERVER &&
+      IsInitializedIPEndPoint(self_address_) &&
+      IsInitializedIPEndPoint(last_packet_destination_address_) &&
+      (!(self_address_ == last_packet_destination_address_))) {
+    SendConnectionCloseWithDetails(
+        QUIC_ERROR_MIGRATING_ADDRESS,
+        "Self address migration is not supported at the server.");
+    return false;
   }
 
   if (!Near(header.packet_number, last_header_.packet_number)) {
@@ -2299,50 +2251,25 @@ void QuicConnection::DiscoverMtu() {
 
 void QuicConnection::MaybeMigrateConnectionToNewPeerAddress() {
   IPEndPoint last_peer_address;
-  if (FLAGS_check_peer_address_change_after_decryption) {
-    last_peer_address = last_packet_source_address_;
-  } else {
-    last_peer_address = IPEndPoint(
-        peer_ip_changed_ ? migrating_peer_ip_ : peer_address_.address(),
-        peer_port_changed_ ? migrating_peer_port_ : peer_address_.port());
-  }
+  last_peer_address = last_packet_source_address_;
   PeerAddressChangeType peer_address_change_type =
       QuicUtils::DetermineAddressChangeType(peer_address_, last_peer_address);
   // TODO(fayang): Currently, all peer address change type are allowed. Need to
   // add a method ShouldAllowPeerAddressChange(PeerAddressChangeType type) to
-  // determine whehter |type| is allowed.
-  if (FLAGS_check_peer_address_change_after_decryption) {
-    if (peer_address_change_type == NO_CHANGE) {
-      return;
-    }
-
-    IPEndPoint old_peer_address = peer_address_;
-    peer_address_ = last_packet_source_address_;
-
-    DVLOG(1) << ENDPOINT << "Peer's ip:port changed from "
-             << old_peer_address.ToString() << " to "
-             << peer_address_.ToString() << ", migrating connection.";
-
-    visitor_->OnConnectionMigration(peer_address_change_type);
-    sent_packet_manager_.OnConnectionMigration(peer_address_change_type);
-
+  // determine whether |type| is allowed.
+  if (peer_address_change_type == NO_CHANGE) {
     return;
   }
 
-  if (peer_ip_changed_ || peer_port_changed_) {
-    IPEndPoint old_peer_address = peer_address_;
-    peer_address_ = IPEndPoint(
-        peer_ip_changed_ ? migrating_peer_ip_ : peer_address_.address(),
-        peer_port_changed_ ? migrating_peer_port_ : peer_address_.port());
+  IPEndPoint old_peer_address = peer_address_;
+  peer_address_ = last_packet_source_address_;
 
-    DVLOG(1) << ENDPOINT << "Peer's ip:port changed from "
-             << old_peer_address.ToString() << " to "
-             << peer_address_.ToString() << ", migrating connection.";
+  DVLOG(1) << ENDPOINT << "Peer's ip:port changed from "
+           << old_peer_address.ToString() << " to " << peer_address_.ToString()
+           << ", migrating connection.";
 
-    visitor_->OnConnectionMigration(peer_address_change_type);
-    DCHECK_NE(peer_address_change_type, NO_CHANGE);
-    sent_packet_manager_.OnConnectionMigration(peer_address_change_type);
-  }
+  visitor_->OnConnectionMigration(peer_address_change_type);
+  sent_packet_manager_.OnConnectionMigration(peer_address_change_type);
 }
 
 void QuicConnection::OnPathClosed(QuicPathId path_id) {