Prepare for ICE-renomination

webrtc/p2p/base/port.h

Index: webrtc/p2p/base/port.h
diff --git a/webrtc/p2p/base/port.h b/webrtc/p2p/base/port.h
index 37926c955603a3f27918270b5b43b177cdccddf9..88a2f84b25d1b513a69f3468dd8a913104733153 100644
--- a/webrtc/p2p/base/port.h
+++ b/webrtc/p2p/base/port.h
@@ -412,11 +412,12 @@ class Connection : public CandidatePairInterface,
                    public sigslot::has_slots<> {
  public:
   struct SentPing {
-    SentPing(const std::string id, int64_t sent_time)
-        : id(id), sent_time(sent_time) {}
+    SentPing(const std::string id, int64_t sent_time, int nomination_value)
+        : id(id), sent_time(sent_time), nomination_value(nomination_value) {}
 
     std::string id;
     int64_t sent_time;
+    int nomination_value;
   };
 
   // States are from RFC 5245. http://tools.ietf.org/html/rfc5245#section-5.7.4
@@ -506,8 +507,21 @@ class Connection : public CandidatePairInterface,
   bool use_candidate_attr() const { return use_candidate_attr_; }
   void set_use_candidate_attr(bool enable);
 
-  bool nominated() const { return nominated_; }
-  void set_nominated(bool nominated) { nominated_ = nominated; }
+  int nominating_value() const { return nominating_value_; }
+  void set_nominating_value(int value) {
+    if (value > nominating_value_) {
+      nominating_value_ = value;
+      nomination_acknowledged_ = false;
+    }

[Taylor Brandstetter, 2016/07/22 17:36:01]

RTC_DCHECK if value < nominating_value_? Or have this function return a bool for
success, and RTC_DCHECK in p2ptransportchannel?

[honghaiz3, 2016/07/22 22:50:11]

It may set a zero-value. 
If we are not using the return value, it is not necessary to return a value. 

[Taylor Brandstetter, 2016/07/22 23:48:29]

I'm suggesting to use the return value in a DCHECK (unless you do the DCHECK in
this method; then nothing would need the return value). Also, if setting a zero
value is always a no-op, there's no point in doing it.

[honghaiz3, 2016/07/25 22:24:41]

I changed the implementation a little. Basically we should always set the value.
So no need to return or DCHECK. 

+  }
+  bool nomination_acknowledged() const { return nomination_acknowledged_; }
+
+  int nominated_value() const { return nominated_value_; }
+  void set_nominated_value(int nominated_value) {

[Taylor Brandstetter, 2016/07/22 17:36:01]

Why is this public? Isn't it only set internally upon receiving a binding
request?

[honghaiz3, 2016/07/22 22:50:11]

This is made public for testing. 
I am really replacing the nominated bool variable with a nominated_value here. 

[Taylor Brandstetter, 2016/07/22 23:48:28]

If this is public only for unit tests, can you make that clear in a comment?
However, it would be much better if the unit tests worked by sending a packet
with the nomination attribute. Is it possible to do that?

[honghaiz3, 2016/07/25 22:24:40]

Done.

+    if (nominated_value > nominated_value_) {
+      nominated_value_ = nominated_value;
+    }
+  }
 
   void set_remote_ice_mode(IceMode mode) {
     remote_ice_mode_ = mode;
@@ -534,7 +548,7 @@ class Connection : public CandidatePairInterface,
   // Called when this connection should try checking writability again.
   int64_t last_ping_sent() const { return last_ping_sent_; }
   void Ping(int64_t now);
-  void ReceivedPingResponse(int rtt);
+  void ReceivedPingResponse(int rtt, const std::string& request_id);
   int64_t last_ping_response_received() const {
     return last_ping_response_received_;
   }
@@ -640,9 +654,21 @@ class Connection : public CandidatePairInterface,
   // But when peer is ice-lite, this flag "must" be initialized to false and
   // turn on when connection becomes "best connection".
   bool use_candidate_attr_;
-  // Whether this connection has been nominated by the controlling side via
-  // the use_candidate attribute.
-  bool nominated_;
+  // Used by the controlling side to indicate that this connection will be
+  // selected for transmission if the peer supports ICE-renomination if this
+  // value is positive. A larger-value indicates that a connection is nominated
+  // later and should be selected by the controlled side with higher precedence.
+  // It should start from zero to indicate not nominating this connection yet.
+  int nominating_value_ = 0;
+  // Whether the current nominating_value has been acknowledged by the peer.
+  // If yes, no nomination-value attribute is needed in the ping request on the
+  // same connection.
+  bool nomination_acknowledged_;
+  // Used by the controlled side to remember the nomination value received from
+  // the controlling side. When the peer does not support ICE re-nomination,
+  // its value will be 1 if the connection is nominated.
+  int nominated_value_ = 0;
+
   IceMode remote_ice_mode_;
   StunRequestManager requests_;
   int rtt_;