Add config to prune TURN ports

webrtc/p2p/client/basicportallocator.cc

Index: webrtc/p2p/client/basicportallocator.cc
diff --git a/webrtc/p2p/client/basicportallocator.cc b/webrtc/p2p/client/basicportallocator.cc
index e39a44013cdcf4f5b4cf627e225c499afb1e1687..3c970f377b031d639369072f16e0da1682681fda 100644
--- a/webrtc/p2p/client/basicportallocator.cc
+++ b/webrtc/p2p/client/basicportallocator.cc
@@ -47,6 +47,36 @@ const int PHASE_SSLTCP = 3;
 
 const int kNumPhases = 4;
 
+// Gets address family priority:  IPv6 > IPv4 > Unspecified.
+int GetAddressFamilyPriority(int ip_family) {
+  switch (ip_family) {
+    case AF_INET6:
+      return 2;
+    case AF_INET:
+      return 1;
+    default:
+      RTC_DCHECK(false);
+      return 0;
+  }
+}
+
+// Returns positive if a is better, negative if b is better, and 0 otherwise.
+int ComparePort(const cricket::Port* a, const cricket::Port* b) {
+  static constexpr int a_is_better = 1;
+  static constexpr int b_is_better = -1;
+  // Protocol type is defined as UDP = 0, TCP = 1, SSLTCP = 2.
+  if (a->GetProtocol() < b->GetProtocol()) {
+    return a_is_better;
+  }
+  if (a->GetProtocol() > b->GetProtocol()) {
+    return b_is_better;
+  }
+
+  int a_family = GetAddressFamilyPriority(a->Network()->GetBestIP().family());
+  int b_family = GetAddressFamilyPriority(b->Network()->GetBestIP().family());
+  return a_family - b_family;
+}
+
 }  // namespace
 
 namespace cricket {
@@ -74,7 +104,7 @@ BasicPortAllocator::BasicPortAllocator(rtc::NetworkManager* network_manager,
                                        const ServerAddresses& stun_servers)
     : network_manager_(network_manager), socket_factory_(socket_factory) {
   ASSERT(socket_factory_ != NULL);
-  SetConfiguration(stun_servers, std::vector<RelayServerConfig>(), 0);
+  SetConfiguration(stun_servers, std::vector<RelayServerConfig>(), 0, false);
   Construct();
 }
 
@@ -101,7 +131,7 @@ BasicPortAllocator::BasicPortAllocator(
     turn_servers.push_back(config);
   }
 
-  SetConfiguration(stun_servers, turn_servers, 0);
+  SetConfiguration(stun_servers, turn_servers, 0, false);
   Construct();
 }
 
@@ -122,7 +152,8 @@ PortAllocatorSession* BasicPortAllocator::CreateSessionInternal(
 void BasicPortAllocator::AddTurnServer(const RelayServerConfig& turn_server) {
   std::vector<RelayServerConfig> new_turn_servers = turn_servers();
   new_turn_servers.push_back(turn_server);
-  SetConfiguration(stun_servers(), new_turn_servers, candidate_pool_size());
+  SetConfiguration(stun_servers(), new_turn_servers, candidate_pool_size(),
+                   prune_turn_ports());
 }
 
 // BasicPortAllocatorSession
@@ -217,9 +248,9 @@ void BasicPortAllocatorSession::ClearGettingPorts() {
 
 std::vector<PortInterface*> BasicPortAllocatorSession::ReadyPorts() const {
   std::vector<PortInterface*> ret;
-  for (const PortData& port : ports_) {
-    if (port.has_pairable_candidate() && !port.error()) {
-      ret.push_back(port.port());
+  for (const PortData& data : ports_) {
+    if (data.ready()) {

[Taylor Brandstetter, 2016/06/29 20:57:35]

To me this is a little confusing because it's not clear what "ready" means, and
I have to look at the header file. Just a matter of preference, but I would be
fine with the whole boolean expression written out everywhere necessary.

[honghaiz3, 2016/06/29 22:53:29]

It basically means the port has a pairable candidate and has not failed or
pruned. I think putting that in a function would increase the code reuse as it
is used multiple times. 

+      ret.push_back(data.port());
     }
   }
   return ret;
@@ -228,6 +259,10 @@ std::vector<PortInterface*> BasicPortAllocatorSession::ReadyPorts() const {
 std::vector<Candidate> BasicPortAllocatorSession::ReadyCandidates() const {
   std::vector<Candidate> candidates;
   for (const PortData& data : ports_) {
+    if (!data.ready()) {
+      continue;
+    }
+
     for (const Candidate& candidate : data.port()->Candidates()) {
       if (!CheckCandidateFilter(candidate)) {
         continue;
@@ -278,16 +313,11 @@ bool BasicPortAllocatorSession::CandidatesAllocationDone() const {
     return false;
   }
 
-  // If all allocated ports are in complete state, session must have got all
+  // If all allocated ports are no longer gathering, session must have got all
   // expected candidates. Session will trigger candidates allocation complete
   // signal.
-  if (!std::all_of(ports_.begin(), ports_.end(), [](const PortData& port) {
-        return (port.complete() || port.error());
-      })) {
-    return false;
-  }
-
-  return true;
+  return std::none_of(ports_.begin(), ports_.end(),
+                      [](const PortData& port) { return port.inprogress(); });
 }
 
 void BasicPortAllocatorSession::OnMessage(rtc::Message *message) {
@@ -357,7 +387,7 @@ void BasicPortAllocatorSession::OnConfigStop() {
   bool send_signal = false;
   for (std::vector<PortData>::iterator it = ports_.begin();
        it != ports_.end(); ++it) {
-    if (!it->complete() && !it->error()) {
+    if (it->inprogress()) {
       // Updating port state to error, which didn't finish allocating candidates
       // yet.
       it->set_error();
@@ -443,11 +473,8 @@ void BasicPortAllocatorSession::DoAllocate() {
     LOG(LS_WARNING) << "Machine has no networks; no ports will be allocated";
     done_signal_needed = true;
   } else {
+    PortConfiguration* config = configs_.empty() ? nullptr : configs_.back();
     for (uint32_t i = 0; i < networks.size(); ++i) {
-      PortConfiguration* config = NULL;
-      if (configs_.size() > 0)
-        config = configs_.back();
-
       uint32_t sequence_flags = flags();
       if ((sequence_flags & DISABLE_ALL_PHASES) == DISABLE_ALL_PHASES) {
         // If all the ports are disabled we should just fire the allocation
@@ -568,37 +595,84 @@ void BasicPortAllocatorSession::OnCandidateReady(
   PortData* data = FindPort(port);
   ASSERT(data != NULL);
   // Discarding any candidate signal if port allocation status is
-  // already in completed state.
-  if (data->complete() || data->error()) {
+  // already done with gathering.
+  if (!data->inprogress()) {
     return;
   }
 
+  // Mark that the port has a pairable candidate, either because we have a
+  // usable candidate from the port, or simply because the port is bound to the
+  // any address and therefore has no host candidate. This will trigger the port
+  // to start creating candidate pairs (connections) and issue connectivity
+  // checks. If port has already been marked as having a pairable candidate,
+  // do nothing here.
+  // Note: We should check whether any candidates may become ready after this
+  // because there we will check whether the candidate is generated by the ready
+  // ports, which may include this port.
+  if (CandidatePairable(c, port) && !data->has_pairable_candidate()) {
+    data->set_has_pairable_candidate(true);
+
+    bool pruned_port = false;
+    if (allocator_->prune_turn_ports() && port->Type() == RELAY_PORT_TYPE) {

[Taylor Brandstetter, 2016/06/29 20:57:35]

It's not safe to access allocator_->prune_turn_ports() directly. If I do:

allocator.SetConfiguration(..., prune=true);
session1 = allocator.CreateSession();
allocator.SetConfiguration(..., prune=false);
session2 = allocator.CreateSession();

I would expect session2 to prune TURN ports and session1 to not. A session
should store the configuration from the time when it was created. This is a
problem I fixed recently with the candidate filter.

[honghaiz3, 2016/06/29 22:53:29]

Good observation. Done. 

+      pruned_port = PruneTurnPorts(port);
+    }
+    // If the current port is not pruned yet, SignalPortReady.
+    if (!data->pruned()) {
+      SignalPortReady(this, port);
+    }
+    // If we have pruned any port, maybe need to signal port allocation done.
+    if (pruned_port) {
+      MaybeSignalCandidatesAllocationDone();

[Taylor Brandstetter, 2016/06/29 20:57:35]

Does this mean we may signal candidate allocation done before we signal the
candidates below? That seems like a problem.

[honghaiz3, 2016/06/29 22:53:29]

Done. Move this after the SignalCandidatesReady. 

+    }
+  }
+
   ProtocolType pvalue;
   bool candidate_protocol_enabled =
       StringToProto(c.protocol().c_str(), &pvalue) &&
       data->sequence()->ProtocolEnabled(pvalue);
 
-  if (CheckCandidateFilter(c) && candidate_protocol_enabled) {
+  if (data->ready() && CheckCandidateFilter(c) && candidate_protocol_enabled) {
     std::vector<Candidate> candidates;
     candidates.push_back(SanitizeRelatedAddress(c));
     SignalCandidatesReady(this, candidates);
   }
+}
 
-  // Port has already been marked as having a pairable candidate.
-  // Nothing to do here.
-  if (data->has_pairable_candidate()) {
-    return;
+Port* BasicPortAllocatorSession::GetBestTurnPortForNetwork(
+    const std::string& network_name) const {
+  Port* best_turn_port = nullptr;
+  for (const PortData& data : ports_) {
+    if (data.port()->Network()->name() == network_name &&
+        data.port()->Type() == RELAY_PORT_TYPE && data.ready() &&
+        (!best_turn_port || ComparePort(data.port(), best_turn_port) > 0)) {
+      best_turn_port = data.port();
+    }
   }
-
-  // Mark that the port has a pairable candidate, either because we have a
-  // usable candidate from the port, or simply because the port is bound to the
-  // any address and therefore has no host candidate. This will trigger the port
-  // to start creating candidate pairs (connections) and issue connectivity
-  // checks.
-  if (CandidatePairable(c, port)) {
-    data->set_has_pairable_candidate(true);
-    SignalPortReady(this, port);
+  return best_turn_port;
+}
+
+bool BasicPortAllocatorSession::PruneTurnPorts(Port* newly_pairable_turn_port) {
+  bool pruned_port = false;
+  // Note: We determine the same network based only on their network names. So
+  // if an IPv4 address and an IPv6 address have the same network name, they
+  // are considered the same network here.
+  const std::string& network_name = newly_pairable_turn_port->Network()->name();
+  Port* best_turn_port = GetBestTurnPortForNetwork(network_name);
+  // |port| is already in the list of ports, so the best port cannot be nullptr.
+  RTC_CHECK(best_turn_port != nullptr);
+
+  for (PortData& data : ports_) {
+    if (data.port()->Network()->name() == network_name &&
+        data.port()->Type() == RELAY_PORT_TYPE && !data.pruned() &&
+        ComparePort(data.port(), best_turn_port) < 0) {
+      data.set_pruned();
+      pruned_port = true;
+      if (data.port() != newly_pairable_turn_port) {
+        SignalPortPruned(this, data.port());
+      }
+    }
   }
+  return pruned_port;
 }
 
 void BasicPortAllocatorSession::OnPortComplete(Port* port) {
@@ -607,7 +681,7 @@ void BasicPortAllocatorSession::OnPortComplete(Port* port) {
   ASSERT(data != NULL);
 
   // Ignore any late signals.
-  if (data->complete() || data->error()) {
+  if (!data->inprogress()) {
     return;
   }
 
@@ -622,7 +696,7 @@ void BasicPortAllocatorSession::OnPortError(Port* port) {
   PortData* data = FindPort(port);
   ASSERT(data != NULL);
   // We might have already given up on this port and stopped it.
-  if (data->complete() || data->error()) {
+  if (!data->inprogress()) {
     return;
   }
 
@@ -1028,13 +1102,11 @@ void AllocationSequence::CreateRelayPorts() {
     return;
   }
 
-  PortConfiguration::RelayList::const_iterator relay;
-  for (relay = config_->relays.begin();
-       relay != config_->relays.end(); ++relay) {
-    if (relay->type == RELAY_GTURN) {
-      CreateGturnPort(*relay);
-    } else if (relay->type == RELAY_TURN) {
-      CreateTurnPort(*relay);
+  for (RelayServerConfig& relay : config_->relays) {
+    if (relay.type == RELAY_GTURN) {
+      CreateGturnPort(relay);
+    } else if (relay.type == RELAY_TURN) {
+      CreateTurnPort(relay);
     } else {
       ASSERT(false);
     }