| /* | 
 |  *  Copyright 2004 The WebRTC Project Authors. All rights reserved. | 
 |  * | 
 |  *  Use of this source code is governed by a BSD-style license | 
 |  *  that can be found in the LICENSE file in the root of the source | 
 |  *  tree. An additional intellectual property rights grant can be found | 
 |  *  in the file PATENTS.  All contributing project authors may | 
 |  *  be found in the AUTHORS file in the root of the source tree. | 
 |  */ | 
 |  | 
 | #include "p2p/client/basic_port_allocator.h" | 
 |  | 
 | #include <algorithm> | 
 | #include <cstddef> | 
 | #include <cstdint> | 
 | #include <functional> | 
 | #include <memory> | 
 | #include <optional> | 
 | #include <set> | 
 | #include <string> | 
 | #include <utility> | 
 | #include <vector> | 
 |  | 
 | #include "absl/algorithm/container.h" | 
 | #include "absl/base/nullability.h" | 
 | #include "absl/memory/memory.h" | 
 | #include "absl/strings/string_view.h" | 
 | #include "api/candidate.h" | 
 | #include "api/environment/environment.h" | 
 | #include "api/field_trials_view.h" | 
 | #include "api/packet_socket_factory.h" | 
 | #include "api/sequence_checker.h" | 
 | #include "api/task_queue/pending_task_safety_flag.h" | 
 | #include "api/transport/enums.h" | 
 | #include "api/units/time_delta.h" | 
 | #include "p2p/base/port.h" | 
 | #include "p2p/base/port_allocator.h" | 
 | #include "p2p/base/port_interface.h" | 
 | #include "p2p/base/stun_port.h" | 
 | #include "p2p/base/tcp_port.h" | 
 | #include "p2p/base/turn_port.h" | 
 | #include "p2p/client/relay_port_factory_interface.h" | 
 | #include "rtc_base/async_packet_socket.h" | 
 | #include "rtc_base/checks.h" | 
 | #include "rtc_base/crypto_random.h" | 
 | #include "rtc_base/ip_address.h" | 
 | #include "rtc_base/logging.h" | 
 | #include "rtc_base/net_helper.h" | 
 | #include "rtc_base/net_helpers.h" | 
 | #include "rtc_base/network.h" | 
 | #include "rtc_base/network/received_packet.h" | 
 | #include "rtc_base/network_constants.h" | 
 | #include "rtc_base/socket_address.h" | 
 | #include "rtc_base/strings/string_builder.h" | 
 | #include "rtc_base/thread.h" | 
 | #include "rtc_base/trace_event.h" | 
 |  | 
 | namespace webrtc { | 
 | namespace { | 
 |  | 
 | const int PHASE_UDP = 0; | 
 | const int PHASE_RELAY = 1; | 
 | const int PHASE_TCP = 2; | 
 |  | 
 | const int kNumPhases = 3; | 
 |  | 
 | // Gets protocol priority: UDP > TCP > SSLTCP == TLS. | 
 | int GetProtocolPriority(ProtocolType protocol) { | 
 |   switch (protocol) { | 
 |     case PROTO_UDP: | 
 |       return 2; | 
 |     case PROTO_TCP: | 
 |       return 1; | 
 |     case PROTO_SSLTCP: | 
 |     case PROTO_TLS: | 
 |       return 0; | 
 |     default: | 
 |       RTC_DCHECK_NOTREACHED(); | 
 |       return 0; | 
 |   } | 
 | } | 
 | // 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_NOTREACHED(); | 
 |       return 0; | 
 |   } | 
 | } | 
 |  | 
 | // Returns positive if a is better, negative if b is better, and 0 otherwise. | 
 | int ComparePort(const Port* a, const Port* b) { | 
 |   int a_protocol = GetProtocolPriority(a->GetProtocol()); | 
 |   int b_protocol = GetProtocolPriority(b->GetProtocol()); | 
 |   int cmp_protocol = a_protocol - b_protocol; | 
 |   if (cmp_protocol != 0) { | 
 |     return cmp_protocol; | 
 |   } | 
 |  | 
 |   int a_family = GetAddressFamilyPriority(a->Network()->GetBestIP().family()); | 
 |   int b_family = GetAddressFamilyPriority(b->Network()->GetBestIP().family()); | 
 |   return a_family - b_family; | 
 | } | 
 |  | 
 | struct NetworkFilter { | 
 |   using Predicate = std::function<bool(const Network*)>; | 
 |   NetworkFilter(Predicate pred, absl::string_view description) | 
 |       : predRemain([pred](const Network* network) { return !pred(network); }), | 
 |         description(description) {} | 
 |   Predicate predRemain; | 
 |   const std::string description; | 
 | }; | 
 |  | 
 | void FilterNetworks(std::vector<const Network*>* networks, | 
 |                     NetworkFilter filter) { | 
 |   auto start_to_remove = | 
 |       std::partition(networks->begin(), networks->end(), filter.predRemain); | 
 |   if (start_to_remove == networks->end()) { | 
 |     return; | 
 |   } | 
 |   RTC_LOG(LS_INFO) << "Filtered out " << filter.description << " networks:"; | 
 |   for (auto it = start_to_remove; it != networks->end(); ++it) { | 
 |     RTC_LOG(LS_INFO) << (*it)->ToString(); | 
 |   } | 
 |   networks->erase(start_to_remove, networks->end()); | 
 | } | 
 |  | 
 | bool IsAllowedByCandidateFilter(const Candidate& c, uint32_t filter) { | 
 |   // When binding to any address, before sending packets out, the getsockname | 
 |   // returns all 0s, but after sending packets, it'll be the NIC used to | 
 |   // send. All 0s is not a valid ICE candidate address and should be filtered | 
 |   // out. | 
 |   if (c.address().IsAnyIP()) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (c.is_relay()) { | 
 |     return ((filter & CF_RELAY) != 0); | 
 |   } | 
 |  | 
 |   if (c.is_stun()) { | 
 |     return ((filter & CF_REFLEXIVE) != 0); | 
 |   } | 
 |  | 
 |   if (c.is_local()) { | 
 |     if ((filter & CF_REFLEXIVE) && !c.address().IsPrivateIP()) { | 
 |       // We allow host candidates if the filter allows server-reflexive | 
 |       // candidates and the candidate is a public IP. Because we don't generate | 
 |       // server-reflexive candidates if they have the same IP as the host | 
 |       // candidate (i.e. when the host candidate is a public IP), filtering to | 
 |       // only server-reflexive candidates won't work right when the host | 
 |       // candidates have public IPs. | 
 |       return true; | 
 |     } | 
 |  | 
 |     return ((filter & CF_HOST) != 0); | 
 |   } | 
 |  | 
 |   return false; | 
 | } | 
 |  | 
 | std::string NetworksToString(const std::vector<const Network*>& networks) { | 
 |   StringBuilder ost; | 
 |   for (auto n : networks) { | 
 |     ost << n->name() << " "; | 
 |   } | 
 |   return ost.Release(); | 
 | } | 
 |  | 
 | }  // namespace | 
 |  | 
 | const uint32_t DISABLE_ALL_PHASES = | 
 |     PORTALLOCATOR_DISABLE_UDP | PORTALLOCATOR_DISABLE_TCP | | 
 |     PORTALLOCATOR_DISABLE_STUN | PORTALLOCATOR_DISABLE_RELAY; | 
 |  | 
 | BasicPortAllocator::BasicPortAllocator( | 
 |     const Environment& env, | 
 |     NetworkManager* absl_nonnull network_manager, | 
 |     PacketSocketFactory* absl_nonnull socket_factory, | 
 |     TurnCustomizer* absl_nullable turn_customizer, | 
 |     RelayPortFactoryInterface* absl_nullable relay_port_factory) | 
 |     : env_(env), | 
 |       network_manager_(network_manager), | 
 |       socket_factory_(socket_factory), | 
 |       relay_port_factory_(relay_port_factory) { | 
 |   RTC_CHECK(socket_factory_); | 
 |   RTC_DCHECK(network_manager_); | 
 |   SetConfiguration(ServerAddresses(), std::vector<RelayServerConfig>(), 0, | 
 |                    NO_PRUNE, turn_customizer); | 
 | } | 
 |  | 
 | BasicPortAllocator::~BasicPortAllocator() { | 
 |   CheckRunOnValidThreadIfInitialized(); | 
 |   // Our created port allocator sessions depend on us, so destroy our remaining | 
 |   // pooled sessions before anything else. | 
 |   DiscardCandidatePool(); | 
 | } | 
 |  | 
 | void BasicPortAllocator::SetNetworkIgnoreMask(int network_ignore_mask) { | 
 |   // TODO(phoglund): implement support for other types than loopback. | 
 |   // See https://code.google.com/p/webrtc/issues/detail?id=4288. | 
 |   // Then remove set_network_ignore_list from NetworkManager. | 
 |   CheckRunOnValidThreadIfInitialized(); | 
 |   network_ignore_mask_ = network_ignore_mask; | 
 | } | 
 |  | 
 | int BasicPortAllocator::GetNetworkIgnoreMask() const { | 
 |   CheckRunOnValidThreadIfInitialized(); | 
 |   int mask = network_ignore_mask_; | 
 |   switch (vpn_preference_) { | 
 |     case VpnPreference::kOnlyUseVpn: | 
 |       mask |= ~static_cast<int>(ADAPTER_TYPE_VPN); | 
 |       break; | 
 |     case VpnPreference::kNeverUseVpn: | 
 |       mask |= static_cast<int>(ADAPTER_TYPE_VPN); | 
 |       break; | 
 |     default: | 
 |       break; | 
 |   } | 
 |   return mask; | 
 | } | 
 |  | 
 | PortAllocatorSession* BasicPortAllocator::CreateSessionInternal( | 
 |     absl::string_view content_name, | 
 |     int component, | 
 |     absl::string_view ice_ufrag, | 
 |     absl::string_view ice_pwd) { | 
 |   CheckRunOnValidThreadAndInitialized(); | 
 |   return new BasicPortAllocatorSession(this, std::string(content_name), | 
 |                                        component, std::string(ice_ufrag), | 
 |                                        std::string(ice_pwd)); | 
 | } | 
 |  | 
 | void BasicPortAllocator::AddTurnServerForTesting( | 
 |     const RelayServerConfig& turn_server) { | 
 |   CheckRunOnValidThreadAndInitialized(); | 
 |   std::vector<RelayServerConfig> new_turn_servers = turn_servers(); | 
 |   new_turn_servers.push_back(turn_server); | 
 |   SetConfiguration(stun_servers(), new_turn_servers, candidate_pool_size(), | 
 |                    turn_port_prune_policy(), turn_customizer()); | 
 | } | 
 |  | 
 | // BasicPortAllocatorSession | 
 | BasicPortAllocatorSession::BasicPortAllocatorSession( | 
 |     BasicPortAllocator* allocator, | 
 |     absl::string_view content_name, | 
 |     int component, | 
 |     absl::string_view ice_ufrag, | 
 |     absl::string_view ice_pwd) | 
 |     : PortAllocatorSession(content_name, | 
 |                            component, | 
 |                            ice_ufrag, | 
 |                            ice_pwd, | 
 |                            allocator->flags()), | 
 |       allocator_(allocator), | 
 |       network_thread_(Thread::Current()), | 
 |       socket_factory_(allocator->socket_factory()), | 
 |       allocation_started_(false), | 
 |       network_manager_started_(false), | 
 |       allocation_sequences_created_(false), | 
 |       turn_port_prune_policy_(allocator->turn_port_prune_policy()) { | 
 |   TRACE_EVENT0("webrtc", | 
 |                "BasicPortAllocatorSession::BasicPortAllocatorSession"); | 
 |   allocator_->network_manager()->SignalNetworksChanged.connect( | 
 |       this, &BasicPortAllocatorSession::OnNetworksChanged); | 
 |   allocator_->network_manager()->StartUpdating(); | 
 | } | 
 |  | 
 | BasicPortAllocatorSession::~BasicPortAllocatorSession() { | 
 |   TRACE_EVENT0("webrtc", | 
 |                "BasicPortAllocatorSession::~BasicPortAllocatorSession"); | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   allocator_->network_manager()->StopUpdating(); | 
 |  | 
 |   for (uint32_t i = 0; i < sequences_.size(); ++i) { | 
 |     // AllocationSequence should clear it's map entry for turn ports before | 
 |     // ports are destroyed. | 
 |     sequences_[i]->Clear(); | 
 |   } | 
 |  | 
 |   std::vector<PortData>::iterator it; | 
 |   for (it = ports_.begin(); it != ports_.end(); it++) | 
 |     delete it->port(); | 
 |  | 
 |   configs_.clear(); | 
 |  | 
 |   for (uint32_t i = 0; i < sequences_.size(); ++i) | 
 |     delete sequences_[i]; | 
 | } | 
 |  | 
 | BasicPortAllocator* BasicPortAllocatorSession::allocator() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   return allocator_; | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::SetCandidateFilter(uint32_t filter) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   if (filter == candidate_filter_) { | 
 |     return; | 
 |   } | 
 |   uint32_t prev_filter = candidate_filter_; | 
 |   candidate_filter_ = filter; | 
 |   for (PortData& port_data : ports_) { | 
 |     if (port_data.error() || port_data.pruned()) { | 
 |       continue; | 
 |     } | 
 |     PortData::State cur_state = port_data.state(); | 
 |     bool found_signalable_candidate = false; | 
 |     bool found_pairable_candidate = false; | 
 |     Port* port = port_data.port(); | 
 |     for (const auto& c : port->Candidates()) { | 
 |       if (!IsStopped() && !IsAllowedByCandidateFilter(c, prev_filter) && | 
 |           IsAllowedByCandidateFilter(c, filter)) { | 
 |         // This candidate was not signaled because of not matching the previous | 
 |         // filter (see OnCandidateReady below). Let the Port to fire the signal | 
 |         // again. | 
 |         // | 
 |         // Note that | 
 |         //  1) we would need the Port to enter the state of in-progress of | 
 |         //     gathering to have candidates signaled; | 
 |         // | 
 |         //  2) firing the signal would also let the session set the port ready | 
 |         //     if needed, so that we could form candidate pairs with candidates | 
 |         //     from this port; | 
 |         // | 
 |         //  *  See again OnCandidateReady below for 1) and 2). | 
 |         // | 
 |         //  3) we only try to resurface candidates if we have not stopped | 
 |         //     getting ports, which is always true for the continual gathering. | 
 |         if (!found_signalable_candidate) { | 
 |           found_signalable_candidate = true; | 
 |           port_data.set_state(PortData::STATE_INPROGRESS); | 
 |         } | 
 |         port->SignalCandidateReady(port, c); | 
 |       } | 
 |  | 
 |       if (CandidatePairable(c, port)) { | 
 |         found_pairable_candidate = true; | 
 |       } | 
 |     } | 
 |     // Restore the previous state. | 
 |     port_data.set_state(cur_state); | 
 |     // Setting a filter may cause a ready port to become non-ready | 
 |     // if it no longer has any pairable candidates. | 
 |     // | 
 |     // Note that we only set for the negative case here, since a port would be | 
 |     // set to have pairable candidates when it signals a ready candidate, which | 
 |     // requires the port is still in the progress of gathering/surfacing | 
 |     // candidates, and would be done in the firing of the signal above. | 
 |     if (!found_pairable_candidate) { | 
 |       port_data.set_has_pairable_candidate(false); | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::StartGettingPorts() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   state_ = SessionState::GATHERING; | 
 |  | 
 |   network_thread_->PostTask( | 
 |       SafeTask(network_safety_.flag(), [this] { GetPortConfigurations(); })); | 
 |  | 
 |   RTC_LOG(LS_INFO) << "Start getting ports with turn_port_prune_policy " | 
 |                    << turn_port_prune_policy_; | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::StopGettingPorts() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   ClearGettingPorts(); | 
 |   // Note: this must be called after ClearGettingPorts because both may set the | 
 |   // session state and we should set the state to STOPPED. | 
 |   state_ = SessionState::STOPPED; | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::ClearGettingPorts() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   ++allocation_epoch_; | 
 |   for (uint32_t i = 0; i < sequences_.size(); ++i) { | 
 |     sequences_[i]->Stop(); | 
 |   } | 
 |   network_thread_->PostTask( | 
 |       SafeTask(network_safety_.flag(), [this] { OnConfigStop(); })); | 
 |   state_ = SessionState::CLEARED; | 
 | } | 
 |  | 
 | bool BasicPortAllocatorSession::IsGettingPorts() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   return state_ == SessionState::GATHERING; | 
 | } | 
 |  | 
 | bool BasicPortAllocatorSession::IsCleared() const { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   return state_ == SessionState::CLEARED; | 
 | } | 
 |  | 
 | bool BasicPortAllocatorSession::IsStopped() const { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   return state_ == SessionState::STOPPED; | 
 | } | 
 |  | 
 | std::vector<const Network*> BasicPortAllocatorSession::GetFailedNetworks() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |  | 
 |   std::vector<const Network*> networks = GetNetworks(); | 
 |   // A network interface may have both IPv4 and IPv6 networks. Only if | 
 |   // neither of the networks has any connections, the network interface | 
 |   // is considered failed and need to be regathered on. | 
 |   std::set<std::string> networks_with_connection; | 
 |   for (const PortData& data : ports_) { | 
 |     Port* port = data.port(); | 
 |     if (!port->connections().empty()) { | 
 |       networks_with_connection.insert(port->Network()->name()); | 
 |     } | 
 |   } | 
 |  | 
 |   networks.erase( | 
 |       std::remove_if(networks.begin(), networks.end(), | 
 |                      [networks_with_connection](const Network* network) { | 
 |                        // If a network does not have any connection, it is | 
 |                        // considered failed. | 
 |                        return networks_with_connection.find(network->name()) != | 
 |                               networks_with_connection.end(); | 
 |                      }), | 
 |       networks.end()); | 
 |   return networks; | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::RegatherOnFailedNetworks() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |  | 
 |   // Find the list of networks that have no connection. | 
 |   std::vector<const Network*> failed_networks = GetFailedNetworks(); | 
 |   if (failed_networks.empty()) { | 
 |     return; | 
 |   } | 
 |  | 
 |   RTC_LOG(LS_INFO) << "Regather candidates on failed networks"; | 
 |  | 
 |   // Mark a sequence as "network failed" if its network is in the list of failed | 
 |   // networks, so that it won't be considered as equivalent when the session | 
 |   // regathers ports and candidates. | 
 |   for (AllocationSequence* sequence : sequences_) { | 
 |     if (!sequence->network_failed() && | 
 |         absl::c_linear_search(failed_networks, sequence->network())) { | 
 |       sequence->set_network_failed(); | 
 |     } | 
 |   } | 
 |  | 
 |   bool disable_equivalent_phases = true; | 
 |   Regather(failed_networks, disable_equivalent_phases, | 
 |            IceRegatheringReason::NETWORK_FAILURE); | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::Regather( | 
 |     const std::vector<const Network*>& networks, | 
 |     bool disable_equivalent_phases, | 
 |     IceRegatheringReason reason) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   // Remove ports from being used locally and send signaling to remove | 
 |   // the candidates on the remote side. | 
 |   std::vector<PortData*> ports_to_prune = GetUnprunedPorts(networks); | 
 |   if (!ports_to_prune.empty()) { | 
 |     RTC_LOG(LS_INFO) << "Prune " << ports_to_prune.size() << " ports"; | 
 |     PrunePortsAndRemoveCandidates(ports_to_prune); | 
 |   } | 
 |  | 
 |   if (allocation_started_ && network_manager_started_ && !IsStopped()) { | 
 |     SignalIceRegathering(this, reason); | 
 |  | 
 |     DoAllocate(disable_equivalent_phases); | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::GetCandidateStatsFromReadyPorts( | 
 |     CandidateStatsList* candidate_stats_list) const { | 
 |   auto ports = ReadyPorts(); | 
 |   for (auto* port : ports) { | 
 |     auto candidates = port->Candidates(); | 
 |     for (const auto& candidate : candidates) { | 
 |       std::optional<StunStats> stun_stats; | 
 |       port->GetStunStats(&stun_stats); | 
 |       CandidateStats candidate_stats(allocator_->SanitizeCandidate(candidate), | 
 |                                      std::move(stun_stats)); | 
 |       candidate_stats_list->push_back(std::move(candidate_stats)); | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::SetStunKeepaliveIntervalForReadyPorts( | 
 |     const std::optional<int>& stun_keepalive_interval) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   auto ports = ReadyPorts(); | 
 |   for (PortInterface* port : ports) { | 
 |     // The port type and protocol can be used to identify different subclasses | 
 |     // of Port in the current implementation. Note that a TCPPort has the type | 
 |     // IceCandidateType::kHost but uses the protocol PROTO_TCP. | 
 |     if (port->Type() == IceCandidateType::kSrflx || | 
 |         (port->Type() == IceCandidateType::kHost && | 
 |          port->GetProtocol() == PROTO_UDP)) { | 
 |       static_cast<UDPPort*>(port)->set_stun_keepalive_delay( | 
 |           stun_keepalive_interval); | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | std::vector<PortInterface*> BasicPortAllocatorSession::ReadyPorts() const { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   std::vector<PortInterface*> ret; | 
 |   for (const PortData& data : ports_) { | 
 |     if (data.ready()) { | 
 |       ret.push_back(data.port()); | 
 |     } | 
 |   } | 
 |   return ret; | 
 | } | 
 |  | 
 | std::vector<Candidate> BasicPortAllocatorSession::ReadyCandidates() const { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   std::vector<Candidate> candidates; | 
 |   for (const PortData& data : ports_) { | 
 |     if (!data.ready()) { | 
 |       continue; | 
 |     } | 
 |     GetCandidatesFromPort(data, &candidates); | 
 |   } | 
 |   return candidates; | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::GetCandidatesFromPort( | 
 |     const PortData& data, | 
 |     std::vector<Candidate>* candidates) const { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   RTC_CHECK(candidates != nullptr); | 
 |   for (const Candidate& candidate : data.port()->Candidates()) { | 
 |     if (!CheckCandidateFilter(candidate)) { | 
 |       continue; | 
 |     } | 
 |     candidates->push_back(allocator_->SanitizeCandidate(candidate)); | 
 |   } | 
 | } | 
 |  | 
 | bool BasicPortAllocator::MdnsObfuscationEnabled() const { | 
 |   return network_manager()->GetMdnsResponder() != nullptr; | 
 | } | 
 |  | 
 | bool BasicPortAllocatorSession::CandidatesAllocationDone() const { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   // Done only if all required AllocationSequence objects | 
 |   // are created. | 
 |   if (!allocation_sequences_created_) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Check that all port allocation sequences are complete (not running). | 
 |   if (absl::c_any_of(sequences_, [](const AllocationSequence* sequence) { | 
 |         return sequence->state() == AllocationSequence::kRunning; | 
 |       })) { | 
 |     return false; | 
 |   } | 
 |  | 
 |   // If all allocated ports are no longer gathering, session must have got all | 
 |   // expected candidates. Session will trigger candidates allocation complete | 
 |   // signal. | 
 |   return absl::c_none_of( | 
 |       ports_, [](const PortData& port) { return port.inprogress(); }); | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::UpdateIceParametersInternal() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   for (PortData& port : ports_) { | 
 |     port.port()->set_content_name(content_name()); | 
 |     port.port()->SetIceParameters(component(), ice_ufrag(), ice_pwd()); | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::GetPortConfigurations() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |  | 
 |   auto config = std::make_unique<PortConfiguration>( | 
 |       allocator_->stun_servers(), username(), password(), | 
 |       &allocator()->env().field_trials()); | 
 |  | 
 |   for (const RelayServerConfig& turn_server : allocator_->turn_servers()) { | 
 |     config->AddRelay(turn_server); | 
 |   } | 
 |   ConfigReady(std::move(config)); | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::ConfigReady(PortConfiguration* config) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   ConfigReady(absl::WrapUnique(config)); | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::ConfigReady( | 
 |     std::unique_ptr<PortConfiguration> config) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   network_thread_->PostTask(SafeTask( | 
 |       network_safety_.flag(), [this, config = std::move(config)]() mutable { | 
 |         OnConfigReady(std::move(config)); | 
 |       })); | 
 | } | 
 |  | 
 | // Adds a configuration to the list. | 
 | void BasicPortAllocatorSession::OnConfigReady( | 
 |     std::unique_ptr<PortConfiguration> config) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   if (config) | 
 |     configs_.push_back(std::move(config)); | 
 |  | 
 |   AllocatePorts(); | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::OnConfigStop() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |  | 
 |   // If any of the allocated ports have not completed the candidates allocation, | 
 |   // mark those as error. Since session doesn't need any new candidates | 
 |   // at this stage of the allocation, it's safe to discard any new candidates. | 
 |   bool send_signal = false; | 
 |   for (std::vector<PortData>::iterator it = ports_.begin(); it != ports_.end(); | 
 |        ++it) { | 
 |     if (it->inprogress()) { | 
 |       // Updating port state to error, which didn't finish allocating candidates | 
 |       // yet. | 
 |       it->set_state(PortData::STATE_ERROR); | 
 |       send_signal = true; | 
 |     } | 
 |   } | 
 |  | 
 |   // Did we stop any running sequences? | 
 |   for (std::vector<AllocationSequence*>::iterator it = sequences_.begin(); | 
 |        it != sequences_.end() && !send_signal; ++it) { | 
 |     if ((*it)->state() == AllocationSequence::kStopped) { | 
 |       send_signal = true; | 
 |     } | 
 |   } | 
 |  | 
 |   // If we stopped anything that was running, send a done signal now. | 
 |   if (send_signal) { | 
 |     MaybeSignalCandidatesAllocationDone(); | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::AllocatePorts() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   network_thread_->PostTask(SafeTask( | 
 |       network_safety_.flag(), [this, allocation_epoch = allocation_epoch_] { | 
 |         OnAllocate(allocation_epoch); | 
 |       })); | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::OnAllocate(int allocation_epoch) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   if (allocation_epoch != allocation_epoch_) | 
 |     return; | 
 |  | 
 |   if (network_manager_started_ && !IsStopped()) { | 
 |     bool disable_equivalent_phases = true; | 
 |     DoAllocate(disable_equivalent_phases); | 
 |   } | 
 |  | 
 |   allocation_started_ = true; | 
 | } | 
 |  | 
 | std::vector<const Network*> BasicPortAllocatorSession::GetNetworks() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   std::vector<const Network*> networks; | 
 |   NetworkManager* network_manager = allocator_->network_manager(); | 
 |   RTC_DCHECK(network_manager != nullptr); | 
 |   // If the network permission state is BLOCKED, we just act as if the flag has | 
 |   // been passed in. | 
 |   if (network_manager->enumeration_permission() == | 
 |       NetworkManager::ENUMERATION_BLOCKED) { | 
 |     set_flags(flags() | PORTALLOCATOR_DISABLE_ADAPTER_ENUMERATION); | 
 |   } | 
 |   // If the adapter enumeration is disabled, we'll just bind to any address | 
 |   // instead of specific NIC. This is to ensure the same routing for http | 
 |   // traffic by OS is also used here to avoid any local or public IP leakage | 
 |   // during stun process. | 
 |   if (flags() & PORTALLOCATOR_DISABLE_ADAPTER_ENUMERATION) { | 
 |     networks = network_manager->GetAnyAddressNetworks(); | 
 |   } else { | 
 |     networks = network_manager->GetNetworks(); | 
 |     // If network enumeration fails, use the ANY address as a fallback, so we | 
 |     // can at least try gathering candidates using the default route chosen by | 
 |     // the OS. Or, if the PORTALLOCATOR_ENABLE_ANY_ADDRESS_PORTS flag is | 
 |     // set, we'll use ANY address candidates either way. | 
 |     if (networks.empty() || | 
 |         (flags() & PORTALLOCATOR_ENABLE_ANY_ADDRESS_PORTS)) { | 
 |       std::vector<const Network*> any_address_networks = | 
 |           network_manager->GetAnyAddressNetworks(); | 
 |       networks.insert(networks.end(), any_address_networks.begin(), | 
 |                       any_address_networks.end()); | 
 |     } | 
 |     RTC_LOG(LS_INFO) << "Count of networks: " << networks.size(); | 
 |     for (const Network* network : networks) { | 
 |       RTC_LOG(LS_INFO) << network->ToString(); | 
 |     } | 
 |   } | 
 |   // Filter out link-local networks if needed. | 
 |   if (flags() & PORTALLOCATOR_DISABLE_LINK_LOCAL_NETWORKS) { | 
 |     NetworkFilter link_local_filter( | 
 |         [](const Network* network) { return IPIsLinkLocal(network->prefix()); }, | 
 |         "link-local"); | 
 |     FilterNetworks(&networks, link_local_filter); | 
 |   } | 
 |   // Do some more filtering, depending on the network ignore mask and "disable | 
 |   // costly networks" flag. | 
 |   NetworkFilter ignored_filter( | 
 |       [this](const Network* network) { | 
 |         return allocator_->GetNetworkIgnoreMask() & network->type(); | 
 |       }, | 
 |       "ignored"); | 
 |   FilterNetworks(&networks, ignored_filter); | 
 |   if (flags() & PORTALLOCATOR_DISABLE_COSTLY_NETWORKS) { | 
 |     uint16_t lowest_cost = kNetworkCostMax; | 
 |     for (const Network* network : networks) { | 
 |       // Don't determine the lowest cost from a link-local network. | 
 |       // On iOS, a device connected to the computer will get a link-local | 
 |       // network for communicating with the computer, however this network can't | 
 |       // be used to connect to a peer outside the network. | 
 |       if (IPIsLinkLocal(network->GetBestIP())) { | 
 |         continue; | 
 |       } | 
 |       lowest_cost = std::min<uint16_t>( | 
 |           lowest_cost, network->GetCost(allocator()->env().field_trials())); | 
 |     } | 
 |     NetworkFilter costly_filter( | 
 |         [lowest_cost, this](const Network* network) { | 
 |           return network->GetCost(allocator()->env().field_trials()) > | 
 |                  lowest_cost + kNetworkCostLow; | 
 |         }, | 
 |         "costly"); | 
 |     FilterNetworks(&networks, costly_filter); | 
 |   } | 
 |  | 
 |   // Lastly, if we have a limit for the number of IPv6 network interfaces (by | 
 |   // default, it's 5), pick IPv6 networks from different interfaces in a | 
 |   // priority order and stick to the limit. | 
 |   std::vector<const Network*> ipv6_networks; | 
 |   for (auto it = networks.begin(); it != networks.end();) { | 
 |     if ((*it)->prefix().family() == AF_INET6) { | 
 |       ipv6_networks.push_back(*it); | 
 |       it = networks.erase(it); | 
 |       continue; | 
 |     } | 
 |     ++it; | 
 |   } | 
 |   ipv6_networks = | 
 |       SelectIPv6Networks(ipv6_networks, allocator_->max_ipv6_networks()); | 
 |   networks.insert(networks.end(), ipv6_networks.begin(), ipv6_networks.end()); | 
 |   return networks; | 
 | } | 
 |  | 
 | std::vector<const Network*> BasicPortAllocatorSession::SelectIPv6Networks( | 
 |     std::vector<const Network*>& all_ipv6_networks, | 
 |     int max_ipv6_networks) { | 
 |   if (static_cast<int>(all_ipv6_networks.size()) <= max_ipv6_networks) { | 
 |     return all_ipv6_networks; | 
 |   } | 
 |   // Adapter types are placed in priority order. Cellular type is an alias of | 
 |   // cellular, 2G..5G types. | 
 |   std::vector<AdapterType> adapter_types = { | 
 |       ADAPTER_TYPE_ETHERNET, ADAPTER_TYPE_LOOPBACK, ADAPTER_TYPE_WIFI, | 
 |       ADAPTER_TYPE_CELLULAR, ADAPTER_TYPE_VPN,      ADAPTER_TYPE_UNKNOWN, | 
 |       ADAPTER_TYPE_ANY}; | 
 |   int adapter_types_cnt = adapter_types.size(); | 
 |   std::vector<const Network*> selected_networks; | 
 |   int adapter_types_pos = 0; | 
 |  | 
 |   while (static_cast<int>(selected_networks.size()) < max_ipv6_networks && | 
 |          adapter_types_pos < adapter_types_cnt * max_ipv6_networks) { | 
 |     int network_pos = 0; | 
 |     while (network_pos < static_cast<int>(all_ipv6_networks.size())) { | 
 |       if (adapter_types[adapter_types_pos % adapter_types_cnt] == | 
 |               all_ipv6_networks[network_pos]->type() || | 
 |           (adapter_types[adapter_types_pos % adapter_types_cnt] == | 
 |                ADAPTER_TYPE_CELLULAR && | 
 |            all_ipv6_networks[network_pos]->IsCellular())) { | 
 |         selected_networks.push_back(all_ipv6_networks[network_pos]); | 
 |         all_ipv6_networks.erase(all_ipv6_networks.begin() + network_pos); | 
 |         break; | 
 |       } | 
 |       network_pos++; | 
 |     } | 
 |     adapter_types_pos++; | 
 |   } | 
 |  | 
 |   return selected_networks; | 
 | } | 
 |  | 
 | // For each network, see if we have a sequence that covers it already.  If not, | 
 | // create a new sequence to create the appropriate ports. | 
 | void BasicPortAllocatorSession::DoAllocate(bool disable_equivalent) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   bool done_signal_needed = false; | 
 |   std::vector<const Network*> networks = GetNetworks(); | 
 |   if (networks.empty()) { | 
 |     RTC_LOG(LS_WARNING) | 
 |         << "Machine has no networks; no ports will be allocated"; | 
 |     done_signal_needed = true; | 
 |   } else { | 
 |     RTC_LOG(LS_INFO) << "Allocate ports on " << NetworksToString(networks); | 
 |     PortConfiguration* config = | 
 |         configs_.empty() ? nullptr : configs_.back().get(); | 
 |     for (uint32_t i = 0; i < networks.size(); ++i) { | 
 |       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 | 
 |         // done event and return. | 
 |         done_signal_needed = true; | 
 |         break; | 
 |       } | 
 |  | 
 |       if (!config || config->relays.empty()) { | 
 |         // No relay ports specified in this config. | 
 |         sequence_flags |= PORTALLOCATOR_DISABLE_RELAY; | 
 |       } | 
 |  | 
 |       if (!(sequence_flags & PORTALLOCATOR_ENABLE_IPV6) && | 
 |           networks[i]->GetBestIP().family() == AF_INET6) { | 
 |         // Skip IPv6 networks unless the flag's been set. | 
 |         continue; | 
 |       } | 
 |  | 
 |       if (!(sequence_flags & PORTALLOCATOR_ENABLE_IPV6_ON_WIFI) && | 
 |           networks[i]->GetBestIP().family() == AF_INET6 && | 
 |           networks[i]->type() == ADAPTER_TYPE_WIFI) { | 
 |         // Skip IPv6 Wi-Fi networks unless the flag's been set. | 
 |         continue; | 
 |       } | 
 |  | 
 |       if (disable_equivalent) { | 
 |         // Disable phases that would only create ports equivalent to | 
 |         // ones that we have already made. | 
 |         DisableEquivalentPhases(networks[i], config, &sequence_flags); | 
 |  | 
 |         if ((sequence_flags & DISABLE_ALL_PHASES) == DISABLE_ALL_PHASES) { | 
 |           // New AllocationSequence would have nothing to do, so don't make it. | 
 |           continue; | 
 |         } | 
 |       } | 
 |  | 
 |       AllocationSequence* sequence = | 
 |           new AllocationSequence(this, networks[i], config, sequence_flags, | 
 |                                  [this, safety_flag = network_safety_.flag()] { | 
 |                                    if (safety_flag->alive()) | 
 |                                      OnPortAllocationComplete(); | 
 |                                  }); | 
 |       sequence->Init(); | 
 |       sequence->Start(); | 
 |       sequences_.push_back(sequence); | 
 |       done_signal_needed = true; | 
 |     } | 
 |   } | 
 |   if (done_signal_needed) { | 
 |     network_thread_->PostTask(SafeTask(network_safety_.flag(), [this] { | 
 |       OnAllocationSequenceObjectsCreated(); | 
 |     })); | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::OnNetworksChanged() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   std::vector<const Network*> networks = GetNetworks(); | 
 |   std::vector<const Network*> failed_networks; | 
 |   for (AllocationSequence* sequence : sequences_) { | 
 |     // Mark the sequence as "network failed" if its network is not in | 
 |     // `networks`. | 
 |     if (!sequence->network_failed() && | 
 |         !absl::c_linear_search(networks, sequence->network())) { | 
 |       sequence->OnNetworkFailed(); | 
 |       failed_networks.push_back(sequence->network()); | 
 |     } | 
 |   } | 
 |   std::vector<PortData*> ports_to_prune = GetUnprunedPorts(failed_networks); | 
 |   if (!ports_to_prune.empty()) { | 
 |     RTC_LOG(LS_INFO) << "Prune " << ports_to_prune.size() | 
 |                      << " ports because their networks were gone"; | 
 |     PrunePortsAndRemoveCandidates(ports_to_prune); | 
 |   } | 
 |  | 
 |   if (allocation_started_ && !IsStopped()) { | 
 |     if (network_manager_started_) { | 
 |       // If the network manager has started, it must be regathering. | 
 |       SignalIceRegathering(this, IceRegatheringReason::NETWORK_CHANGE); | 
 |     } | 
 |     bool disable_equivalent_phases = true; | 
 |     DoAllocate(disable_equivalent_phases); | 
 |   } | 
 |  | 
 |   if (!network_manager_started_) { | 
 |     RTC_LOG(LS_INFO) << "Network manager has started"; | 
 |     network_manager_started_ = true; | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::DisableEquivalentPhases( | 
 |     const Network* network, | 
 |     PortConfiguration* config, | 
 |     uint32_t* flags) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   for (uint32_t i = 0; i < sequences_.size() && | 
 |                        (*flags & DISABLE_ALL_PHASES) != DISABLE_ALL_PHASES; | 
 |        ++i) { | 
 |     sequences_[i]->DisableEquivalentPhases(network, config, flags); | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::AddAllocatedPort(Port* port, | 
 |                                                  AllocationSequence* seq) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   if (!port) | 
 |     return; | 
 |  | 
 |   RTC_LOG(LS_INFO) << "Adding allocated port for " << content_name(); | 
 |   port->set_content_name(content_name()); | 
 |   port->set_component(component()); | 
 |   port->set_generation(generation()); | 
 |   port->set_send_retransmit_count_attribute( | 
 |       (flags() & PORTALLOCATOR_ENABLE_STUN_RETRANSMIT_ATTRIBUTE) != 0); | 
 |  | 
 |   PortData data(port, seq); | 
 |   ports_.push_back(data); | 
 |  | 
 |   port->SignalCandidateReady.connect( | 
 |       this, &BasicPortAllocatorSession::OnCandidateReady); | 
 |   port->SignalCandidateError.connect( | 
 |       this, &BasicPortAllocatorSession::OnCandidateError); | 
 |   port->SignalPortComplete.connect(this, | 
 |                                    &BasicPortAllocatorSession::OnPortComplete); | 
 |   port->SubscribePortDestroyed( | 
 |       [this](PortInterface* port) { OnPortDestroyed(port); }); | 
 |  | 
 |   port->SignalPortError.connect(this, &BasicPortAllocatorSession::OnPortError); | 
 |   RTC_LOG(LS_INFO) << port->ToString() << ": Added port to allocator"; | 
 |  | 
 |   port->PrepareAddress(); | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::OnAllocationSequenceObjectsCreated() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   allocation_sequences_created_ = true; | 
 |   // Send candidate allocation complete signal if we have no sequences. | 
 |   MaybeSignalCandidatesAllocationDone(); | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::OnCandidateReady(Port* port, | 
 |                                                  const Candidate& c) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   PortData* data = FindPort(port); | 
 |   RTC_DCHECK(data != nullptr); | 
 |   RTC_LOG(LS_INFO) << port->ToString() | 
 |                    << ": Gathered candidate: " << c.ToSensitiveString(); | 
 |   // Discarding any candidate signal if port allocation status is | 
 |   // already done with gathering. | 
 |   if (!data->inprogress()) { | 
 |     RTC_LOG(LS_WARNING) | 
 |         << "Discarding candidate because port is already done gathering."; | 
 |     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. | 
 |   bool pruned = false; | 
 |   if (CandidatePairable(c, port) && !data->has_pairable_candidate()) { | 
 |     data->set_has_pairable_candidate(true); | 
 |  | 
 |     if (port->Type() == IceCandidateType::kRelay) { | 
 |       if (turn_port_prune_policy_ == KEEP_FIRST_READY) { | 
 |         pruned = PruneNewlyPairableTurnPort(data); | 
 |       } else if (turn_port_prune_policy_ == PRUNE_BASED_ON_PRIORITY) { | 
 |         pruned = PruneTurnPorts(port); | 
 |       } | 
 |     } | 
 |  | 
 |     // If the current port is not pruned yet, SignalPortReady. | 
 |     if (!data->pruned()) { | 
 |       RTC_LOG(LS_INFO) << port->ToString() << ": Port ready."; | 
 |       SignalPortReady(this, port); | 
 |       port->KeepAliveUntilPruned(); | 
 |     } | 
 |   } | 
 |  | 
 |   if (data->ready() && CheckCandidateFilter(c)) { | 
 |     std::vector<Candidate> candidates; | 
 |     candidates.push_back(allocator_->SanitizeCandidate(c)); | 
 |     SignalCandidatesReady(this, candidates); | 
 |   } else { | 
 |     RTC_LOG(LS_INFO) << "Discarding candidate because it doesn't match filter."; | 
 |   } | 
 |  | 
 |   // If we have pruned any port, maybe need to signal port allocation done. | 
 |   if (pruned) { | 
 |     MaybeSignalCandidatesAllocationDone(); | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::OnCandidateError( | 
 |     Port* port, | 
 |     const IceCandidateErrorEvent& event) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   RTC_DCHECK(FindPort(port)); | 
 |   if (event.address.empty()) { | 
 |     candidate_error_events_.push_back(event); | 
 |   } else { | 
 |     SignalCandidateError(this, event); | 
 |   } | 
 | } | 
 |  | 
 | Port* BasicPortAllocatorSession::GetBestTurnPortForNetwork( | 
 |     absl::string_view network_name) const { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   Port* best_turn_port = nullptr; | 
 |   for (const PortData& data : ports_) { | 
 |     if (data.port()->Network()->name() == network_name && | 
 |         data.port()->Type() == IceCandidateType::kRelay && data.ready() && | 
 |         (!best_turn_port || ComparePort(data.port(), best_turn_port) > 0)) { | 
 |       best_turn_port = data.port(); | 
 |     } | 
 |   } | 
 |   return best_turn_port; | 
 | } | 
 |  | 
 | bool BasicPortAllocatorSession::PruneNewlyPairableTurnPort( | 
 |     PortData* newly_pairable_port_data) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   RTC_DCHECK(newly_pairable_port_data->port()->Type() == | 
 |              IceCandidateType::kRelay); | 
 |   // If an existing turn port is ready on the same network, prune the newly | 
 |   // pairable port. | 
 |   const std::string& network_name = | 
 |       newly_pairable_port_data->port()->Network()->name(); | 
 |  | 
 |   for (PortData& data : ports_) { | 
 |     if (data.port()->Network()->name() == network_name && | 
 |         data.port()->Type() == IceCandidateType::kRelay && data.ready() && | 
 |         &data != newly_pairable_port_data) { | 
 |       RTC_LOG(LS_INFO) << "Port pruned: " | 
 |                        << newly_pairable_port_data->port()->ToString(); | 
 |       newly_pairable_port_data->Prune(); | 
 |       return true; | 
 |     } | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | bool BasicPortAllocatorSession::PruneTurnPorts(Port* newly_pairable_turn_port) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   // 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); | 
 |  | 
 |   bool pruned = false; | 
 |   std::vector<PortData*> ports_to_prune; | 
 |   for (PortData& data : ports_) { | 
 |     if (data.port()->Network()->name() == network_name && | 
 |         data.port()->Type() == IceCandidateType::kRelay && !data.pruned() && | 
 |         ComparePort(data.port(), best_turn_port) < 0) { | 
 |       pruned = true; | 
 |       if (data.port() != newly_pairable_turn_port) { | 
 |         // These ports will be pruned in PrunePortsAndRemoveCandidates. | 
 |         ports_to_prune.push_back(&data); | 
 |       } else { | 
 |         data.Prune(); | 
 |       } | 
 |     } | 
 |   } | 
 |  | 
 |   if (!ports_to_prune.empty()) { | 
 |     RTC_LOG(LS_INFO) << "Prune " << ports_to_prune.size() | 
 |                      << " low-priority TURN ports"; | 
 |     PrunePortsAndRemoveCandidates(ports_to_prune); | 
 |   } | 
 |   return pruned; | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::PruneAllPorts() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   for (PortData& data : ports_) { | 
 |     data.Prune(); | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::OnPortComplete(Port* port) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   RTC_LOG(LS_INFO) << port->ToString() | 
 |                    << ": Port completed gathering candidates."; | 
 |   PortData* data = FindPort(port); | 
 |   RTC_DCHECK(data != nullptr); | 
 |  | 
 |   // Ignore any late signals. | 
 |   if (!data->inprogress()) { | 
 |     return; | 
 |   } | 
 |  | 
 |   // Moving to COMPLETE state. | 
 |   data->set_state(PortData::STATE_COMPLETE); | 
 |   // Send candidate allocation complete signal if this was the last port. | 
 |   MaybeSignalCandidatesAllocationDone(); | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::OnPortError(Port* port) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   RTC_LOG(LS_INFO) << port->ToString() | 
 |                    << ": Port encountered error while gathering candidates."; | 
 |   PortData* data = FindPort(port); | 
 |   RTC_DCHECK(data != nullptr); | 
 |   // We might have already given up on this port and stopped it. | 
 |   if (!data->inprogress()) { | 
 |     return; | 
 |   } | 
 |  | 
 |   // SignalAddressError is currently sent from StunPort/TurnPort. | 
 |   // But this signal itself is generic. | 
 |   data->set_state(PortData::STATE_ERROR); | 
 |   // Send candidate allocation complete signal if this was the last port. | 
 |   MaybeSignalCandidatesAllocationDone(); | 
 | } | 
 |  | 
 | bool BasicPortAllocatorSession::CheckCandidateFilter(const Candidate& c) const { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |  | 
 |   return IsAllowedByCandidateFilter(c, candidate_filter_); | 
 | } | 
 |  | 
 | bool BasicPortAllocatorSession::CandidatePairable(const Candidate& c, | 
 |                                                   const Port* port) const { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |  | 
 |   bool candidate_signalable = CheckCandidateFilter(c); | 
 |  | 
 |   // When device enumeration is disabled (to prevent non-default IP addresses | 
 |   // from leaking), we ping from some local candidates even though we don't | 
 |   // signal them. However, if host candidates are also disabled (for example, to | 
 |   // prevent even default IP addresses from leaking), we still don't want to | 
 |   // ping from them, even if device enumeration is disabled.  Thus, we check for | 
 |   // both device enumeration and host candidates being disabled. | 
 |   bool network_enumeration_disabled = c.address().IsAnyIP(); | 
 |   bool can_ping_from_candidate = | 
 |       (port->SharedSocket() || c.protocol() == TCP_PROTOCOL_NAME); | 
 |   bool host_candidates_disabled = !(candidate_filter_ & CF_HOST); | 
 |  | 
 |   return candidate_signalable || | 
 |          (network_enumeration_disabled && can_ping_from_candidate && | 
 |           !host_candidates_disabled); | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::OnPortAllocationComplete() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   // Send candidate allocation complete signal if all ports are done. | 
 |   MaybeSignalCandidatesAllocationDone(); | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::MaybeSignalCandidatesAllocationDone() { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   if (CandidatesAllocationDone()) { | 
 |     if (pooled()) { | 
 |       RTC_LOG(LS_INFO) << "All candidates gathered for pooled session."; | 
 |     } else { | 
 |       RTC_LOG(LS_INFO) << "All candidates gathered for " << content_name() | 
 |                        << ":" << component() << ":" << generation(); | 
 |     } | 
 |     for (const auto& event : candidate_error_events_) { | 
 |       SignalCandidateError(this, event); | 
 |     } | 
 |     candidate_error_events_.clear(); | 
 |     SignalCandidatesAllocationDone(this); | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::OnPortDestroyed(PortInterface* port) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   for (std::vector<PortData>::iterator iter = ports_.begin(); | 
 |        iter != ports_.end(); ++iter) { | 
 |     if (port == iter->port()) { | 
 |       ports_.erase(iter); | 
 |       RTC_LOG(LS_INFO) << port->ToString() << ": Removed port from allocator (" | 
 |                        << static_cast<int>(ports_.size()) << " remaining)"; | 
 |       return; | 
 |     } | 
 |   } | 
 |   RTC_DCHECK_NOTREACHED(); | 
 | } | 
 |  | 
 | BasicPortAllocatorSession::PortData* BasicPortAllocatorSession::FindPort( | 
 |     Port* port) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   for (std::vector<PortData>::iterator it = ports_.begin(); it != ports_.end(); | 
 |        ++it) { | 
 |     if (it->port() == port) { | 
 |       return &*it; | 
 |     } | 
 |   } | 
 |   return nullptr; | 
 | } | 
 |  | 
 | std::vector<BasicPortAllocatorSession::PortData*> | 
 | BasicPortAllocatorSession::GetUnprunedPorts( | 
 |     const std::vector<const Network*>& networks) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   std::vector<PortData*> unpruned_ports; | 
 |   for (PortData& port : ports_) { | 
 |     if (!port.pruned() && | 
 |         absl::c_linear_search(networks, port.sequence()->network())) { | 
 |       unpruned_ports.push_back(&port); | 
 |     } | 
 |   } | 
 |   return unpruned_ports; | 
 | } | 
 |  | 
 | void BasicPortAllocatorSession::PrunePortsAndRemoveCandidates( | 
 |     const std::vector<PortData*>& port_data_list) { | 
 |   RTC_DCHECK_RUN_ON(network_thread_); | 
 |   std::vector<PortInterface*> pruned_ports; | 
 |   std::vector<Candidate> removed_candidates; | 
 |   for (PortData* data : port_data_list) { | 
 |     // Prune the port so that it may be destroyed. | 
 |     data->Prune(); | 
 |     pruned_ports.push_back(data->port()); | 
 |     if (data->has_pairable_candidate()) { | 
 |       GetCandidatesFromPort(*data, &removed_candidates); | 
 |       // Mark the port as having no pairable candidates so that its candidates | 
 |       // won't be removed multiple times. | 
 |       data->set_has_pairable_candidate(false); | 
 |     } | 
 |   } | 
 |   if (!pruned_ports.empty()) { | 
 |     SignalPortsPruned(this, pruned_ports); | 
 |   } | 
 |   if (!removed_candidates.empty()) { | 
 |     RTC_LOG(LS_INFO) << "Removed " << removed_candidates.size() | 
 |                      << " candidates"; | 
 |     SignalCandidatesRemoved(this, removed_candidates); | 
 |   } | 
 | } | 
 |  | 
 | void BasicPortAllocator::SetVpnList(const std::vector<NetworkMask>& vpn_list) { | 
 |   network_manager_->set_vpn_list(vpn_list); | 
 | } | 
 |  | 
 | // AllocationSequence | 
 |  | 
 | AllocationSequence::AllocationSequence( | 
 |     BasicPortAllocatorSession* session, | 
 |     const Network* network, | 
 |     PortConfiguration* config, | 
 |     uint32_t flags, | 
 |     std::function<void()> port_allocation_complete_callback) | 
 |     : session_(session), | 
 |       network_(network), | 
 |       config_(config), | 
 |       state_(kInit), | 
 |       flags_(flags), | 
 |       udp_socket_(), | 
 |       udp_port_(nullptr), | 
 |       phase_(0), | 
 |       port_allocation_complete_callback_( | 
 |           std::move(port_allocation_complete_callback)) {} | 
 |  | 
 | void AllocationSequence::Init() { | 
 |   if (IsFlagSet(PORTALLOCATOR_ENABLE_SHARED_SOCKET)) { | 
 |     udp_socket_.reset(session_->socket_factory()->CreateUdpSocket( | 
 |         SocketAddress(network_->GetBestIP(), 0), | 
 |         session_->allocator()->min_port(), session_->allocator()->max_port())); | 
 |     if (udp_socket_) { | 
 |       udp_socket_->RegisterReceivedPacketCallback( | 
 |           [&](AsyncPacketSocket* socket, const ReceivedIpPacket& packet) { | 
 |             OnReadPacket(socket, packet); | 
 |           }); | 
 |     } | 
 |     // Continuing if `udp_socket_` is NULL, as local TCP and RelayPort using TCP | 
 |     // are next available options to setup a communication channel. | 
 |   } | 
 | } | 
 |  | 
 | void AllocationSequence::Clear() { | 
 |   TRACE_EVENT0("webrtc", "AllocationSequence::Clear"); | 
 |   udp_port_ = nullptr; | 
 |   relay_ports_.clear(); | 
 | } | 
 |  | 
 | void AllocationSequence::OnNetworkFailed() { | 
 |   RTC_DCHECK(!network_failed_); | 
 |   network_failed_ = true; | 
 |   // Stop the allocation sequence if its network failed. | 
 |   Stop(); | 
 | } | 
 |  | 
 | void AllocationSequence::DisableEquivalentPhases(const Network* network, | 
 |                                                  PortConfiguration* config, | 
 |                                                  uint32_t* flags) { | 
 |   if (network_failed_) { | 
 |     // If the network of this allocation sequence has ever become failed, | 
 |     // it won't be equivalent to the new network. | 
 |     return; | 
 |   } | 
 |  | 
 |   if (!((network == network_) && (previous_best_ip_ == network->GetBestIP()))) { | 
 |     // Different network setup; nothing is equivalent. | 
 |     return; | 
 |   } | 
 |  | 
 |   // Else turn off the stuff that we've already got covered. | 
 |  | 
 |   // Every config implicitly specifies local, so turn that off right away if we | 
 |   // already have a port of the corresponding type. Look for a port that | 
 |   // matches this AllocationSequence's network, is the right protocol, and | 
 |   // hasn't encountered an error. | 
 |   // TODO(deadbeef): This doesn't take into account that there may be another | 
 |   // AllocationSequence that's ABOUT to allocate a UDP port, but hasn't yet. | 
 |   // This can happen if, say, there's a network change event right before an | 
 |   // application-triggered ICE restart. Hopefully this problem will just go | 
 |   // away if we get rid of the gathering "phases" though, which is planned. | 
 |   // | 
 |   // | 
 |   // PORTALLOCATOR_DISABLE_UDP is used to disable a Port from gathering the host | 
 |   // candidate (and srflx candidate if Port::SharedSocket()), and we do not want | 
 |   // to disable the gathering of these candidates just becaue of an existing | 
 |   // Port over PROTO_UDP, namely a TurnPort over UDP. | 
 |   if (absl::c_any_of(session_->ports_, | 
 |                      [this](const BasicPortAllocatorSession::PortData& p) { | 
 |                        return !p.pruned() && p.port()->Network() == network_ && | 
 |                               p.port()->GetProtocol() == PROTO_UDP && | 
 |                               p.port()->Type() == IceCandidateType::kHost && | 
 |                               !p.error(); | 
 |                      })) { | 
 |     *flags |= PORTALLOCATOR_DISABLE_UDP; | 
 |   } | 
 |   // Similarly we need to check both the protocol used by an existing Port and | 
 |   // its type. | 
 |   if (absl::c_any_of(session_->ports_, | 
 |                      [this](const BasicPortAllocatorSession::PortData& p) { | 
 |                        return !p.pruned() && p.port()->Network() == network_ && | 
 |                               p.port()->GetProtocol() == PROTO_TCP && | 
 |                               p.port()->Type() == IceCandidateType::kHost && | 
 |                               !p.error(); | 
 |                      })) { | 
 |     *flags |= PORTALLOCATOR_DISABLE_TCP; | 
 |   } | 
 |  | 
 |   if (config_ && config) { | 
 |     // We need to regather srflx candidates if either of the following | 
 |     // conditions occurs: | 
 |     //  1. The STUN servers are different from the previous gathering. | 
 |     //  2. We will regather host candidates, hence possibly inducing new NAT | 
 |     //     bindings. | 
 |     if (config_->StunServers() == config->StunServers() && | 
 |         (*flags & PORTALLOCATOR_DISABLE_UDP)) { | 
 |       // Already got this STUN servers covered. | 
 |       *flags |= PORTALLOCATOR_DISABLE_STUN; | 
 |     } | 
 |     if (!config_->relays.empty()) { | 
 |       // Already got relays covered. | 
 |       // NOTE: This will even skip a _different_ set of relay servers if we | 
 |       // were to be given one, but that never happens in our codebase. Should | 
 |       // probably get rid of the list in PortConfiguration and just keep a | 
 |       // single relay server in each one. | 
 |       *flags |= PORTALLOCATOR_DISABLE_RELAY; | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void AllocationSequence::Start() { | 
 |   state_ = kRunning; | 
 |  | 
 |   session_->network_thread()->PostTask( | 
 |       SafeTask(safety_.flag(), [this, epoch = epoch_] { Process(epoch); })); | 
 |   // Take a snapshot of the best IP, so that when DisableEquivalentPhases is | 
 |   // called next time, we enable all phases if the best IP has since changed. | 
 |   previous_best_ip_ = network_->GetBestIP(); | 
 | } | 
 |  | 
 | void AllocationSequence::Stop() { | 
 |   // If the port is completed, don't set it to stopped. | 
 |   if (state_ == kRunning) { | 
 |     state_ = kStopped; | 
 |     // Cause further Process calls in the previous epoch to be ignored. | 
 |     ++epoch_; | 
 |   } | 
 | } | 
 |  | 
 | void AllocationSequence::Process(int epoch) { | 
 |   RTC_DCHECK(Thread::Current() == session_->network_thread()); | 
 |   const char* const PHASE_NAMES[kNumPhases] = {"Udp", "Relay", "Tcp"}; | 
 |  | 
 |   if (epoch != epoch_) | 
 |     return; | 
 |  | 
 |   // Perform all of the phases in the current step. | 
 |   RTC_LOG(LS_INFO) << network_->ToString() | 
 |                    << ": Allocation Phase=" << PHASE_NAMES[phase_]; | 
 |  | 
 |   switch (phase_) { | 
 |     case PHASE_UDP: | 
 |       CreateUDPPorts(); | 
 |       CreateStunPorts(); | 
 |       break; | 
 |  | 
 |     case PHASE_RELAY: | 
 |       CreateRelayPorts(); | 
 |       break; | 
 |  | 
 |     case PHASE_TCP: | 
 |       CreateTCPPorts(); | 
 |       state_ = kCompleted; | 
 |       break; | 
 |  | 
 |     default: | 
 |       RTC_DCHECK_NOTREACHED(); | 
 |   } | 
 |  | 
 |   if (state() == kRunning) { | 
 |     ++phase_; | 
 |     session_->network_thread()->PostDelayedTask( | 
 |         SafeTask(safety_.flag(), [this, epoch = epoch_] { Process(epoch); }), | 
 |         TimeDelta::Millis(session_->allocator()->step_delay())); | 
 |   } else { | 
 |     // No allocation steps needed further if all phases in AllocationSequence | 
 |     // are completed. Cause further Process calls in the previous epoch to be | 
 |     // ignored. | 
 |     ++epoch_; | 
 |     port_allocation_complete_callback_(); | 
 |   } | 
 | } | 
 |  | 
 | void AllocationSequence::CreateUDPPorts() { | 
 |   if (IsFlagSet(PORTALLOCATOR_DISABLE_UDP)) { | 
 |     RTC_LOG(LS_VERBOSE) << "AllocationSequence: UDP ports disabled, skipping."; | 
 |     return; | 
 |   } | 
 |  | 
 |   // TODO(mallinath) - Remove UDPPort creating socket after shared socket | 
 |   // is enabled completely. | 
 |   std::unique_ptr<UDPPort> port; | 
 |   bool emit_local_candidate_for_anyaddress = | 
 |       !IsFlagSet(PORTALLOCATOR_DISABLE_DEFAULT_LOCAL_CANDIDATE); | 
 |   if (IsFlagSet(PORTALLOCATOR_ENABLE_SHARED_SOCKET) && udp_socket_) { | 
 |     port = UDPPort::Create( | 
 |         {.env = session_->allocator()->env(), | 
 |          .network_thread = session_->network_thread(), | 
 |          .socket_factory = session_->socket_factory(), | 
 |          .network = network_, | 
 |          .ice_username_fragment = session_->username(), | 
 |          .ice_password = session_->password()}, | 
 |         udp_socket_.get(), emit_local_candidate_for_anyaddress, | 
 |         session_->allocator()->stun_candidate_keepalive_interval()); | 
 |   } else { | 
 |     port = UDPPort::Create( | 
 |         {.env = session_->allocator()->env(), | 
 |          .network_thread = session_->network_thread(), | 
 |          .socket_factory = session_->socket_factory(), | 
 |          .network = network_, | 
 |          .ice_username_fragment = session_->username(), | 
 |          .ice_password = session_->password()}, | 
 |         session_->allocator()->min_port(), session_->allocator()->max_port(), | 
 |         emit_local_candidate_for_anyaddress, | 
 |         session_->allocator()->stun_candidate_keepalive_interval()); | 
 |   } | 
 |  | 
 |   if (port) { | 
 |     port->SetIceTiebreaker(session_->allocator()->ice_tiebreaker()); | 
 |     // If shared socket is enabled, STUN candidate will be allocated by the | 
 |     // UDPPort. | 
 |     if (IsFlagSet(PORTALLOCATOR_ENABLE_SHARED_SOCKET)) { | 
 |       udp_port_ = port.get(); | 
 |       port->SubscribePortDestroyed( | 
 |           [this](PortInterface* port) { OnPortDestroyed(port); }); | 
 |  | 
 |       // If STUN is not disabled, setting stun server address to port. | 
 |       if (!IsFlagSet(PORTALLOCATOR_DISABLE_STUN)) { | 
 |         if (config_ && !config_->StunServers().empty()) { | 
 |           RTC_LOG(LS_INFO) | 
 |               << "AllocationSequence: UDPPort will be handling the " | 
 |                  "STUN candidate generation."; | 
 |           port->set_server_addresses(config_->StunServers()); | 
 |         } | 
 |       } | 
 |     } | 
 |  | 
 |     session_->AddAllocatedPort(port.release(), this); | 
 |   } | 
 | } | 
 |  | 
 | void AllocationSequence::CreateTCPPorts() { | 
 |   if (IsFlagSet(PORTALLOCATOR_DISABLE_TCP)) { | 
 |     RTC_LOG(LS_VERBOSE) << "AllocationSequence: TCP ports disabled, skipping."; | 
 |     return; | 
 |   } | 
 |  | 
 |   std::unique_ptr<Port> port = TCPPort::Create( | 
 |       {.env = session_->allocator()->env(), | 
 |        .network_thread = session_->network_thread(), | 
 |        .socket_factory = session_->socket_factory(), | 
 |        .network = network_, | 
 |        .ice_username_fragment = session_->username(), | 
 |        .ice_password = session_->password()}, | 
 |       session_->allocator()->min_port(), session_->allocator()->max_port(), | 
 |       session_->allocator()->allow_tcp_listen()); | 
 |   if (port) { | 
 |     port->SetIceTiebreaker(session_->allocator()->ice_tiebreaker()); | 
 |     session_->AddAllocatedPort(port.release(), this); | 
 |     // Since TCPPort is not created using shared socket, `port` will not be | 
 |     // added to the dequeue. | 
 |   } | 
 | } | 
 |  | 
 | void AllocationSequence::CreateStunPorts() { | 
 |   if (IsFlagSet(PORTALLOCATOR_DISABLE_STUN)) { | 
 |     RTC_LOG(LS_VERBOSE) << "AllocationSequence: STUN ports disabled, skipping."; | 
 |     return; | 
 |   } | 
 |  | 
 |   if (IsFlagSet(PORTALLOCATOR_ENABLE_SHARED_SOCKET)) { | 
 |     return; | 
 |   } | 
 |  | 
 |   if (!(config_ && !config_->StunServers().empty())) { | 
 |     RTC_LOG(LS_WARNING) | 
 |         << "AllocationSequence: No STUN server configured, skipping."; | 
 |     return; | 
 |   } | 
 |  | 
 |   std::unique_ptr<StunPort> port = StunPort::Create( | 
 |       {.env = session_->allocator()->env(), | 
 |        .network_thread = session_->network_thread(), | 
 |        .socket_factory = session_->socket_factory(), | 
 |        .network = network_, | 
 |        .ice_username_fragment = session_->username(), | 
 |        .ice_password = session_->password()}, | 
 |       session_->allocator()->min_port(), session_->allocator()->max_port(), | 
 |       config_->StunServers(), | 
 |       session_->allocator()->stun_candidate_keepalive_interval()); | 
 |   if (port) { | 
 |     port->SetIceTiebreaker(session_->allocator()->ice_tiebreaker()); | 
 |     session_->AddAllocatedPort(port.release(), this); | 
 |     // Since StunPort is not created using shared socket, `port` will not be | 
 |     // added to the dequeue. | 
 |   } | 
 | } | 
 |  | 
 | void AllocationSequence::CreateRelayPorts() { | 
 |   if (IsFlagSet(PORTALLOCATOR_DISABLE_RELAY)) { | 
 |     RTC_LOG(LS_VERBOSE) | 
 |         << "AllocationSequence: Relay ports disabled, skipping."; | 
 |     return; | 
 |   } | 
 |  | 
 |   // If BasicPortAllocatorSession::OnAllocate left relay ports enabled then we | 
 |   // ought to have a relay list for them here. | 
 |   RTC_DCHECK(config_); | 
 |   RTC_DCHECK(!config_->relays.empty()); | 
 |   if (!(config_ && !config_->relays.empty())) { | 
 |     RTC_LOG(LS_WARNING) | 
 |         << "AllocationSequence: No relay server configured, skipping."; | 
 |     return; | 
 |   } | 
 |  | 
 |   // Relative priority of candidates from this TURN server in relation | 
 |   // to the candidates from other servers. Required because ICE priorities | 
 |   // need to be unique. | 
 |   int relative_priority = config_->relays.size(); | 
 |   for (RelayServerConfig& relay : config_->relays) { | 
 |     CreateTurnPort(relay, relative_priority--); | 
 |   } | 
 | } | 
 |  | 
 | void AllocationSequence::CreateTurnPort(const RelayServerConfig& config, | 
 |                                         int relative_priority) { | 
 |   PortList::const_iterator relay_port; | 
 |   for (relay_port = config.ports.begin(); relay_port != config.ports.end(); | 
 |        ++relay_port) { | 
 |     // Skip UDP connections to relay servers if it's disallowed. | 
 |     if (IsFlagSet(PORTALLOCATOR_DISABLE_UDP_RELAY) && | 
 |         relay_port->proto == PROTO_UDP) { | 
 |       continue; | 
 |     } | 
 |  | 
 |     // Do not create a port if the server address family is known and does | 
 |     // not match the local IP address family. | 
 |     int server_ip_family = relay_port->address.ipaddr().family(); | 
 |     int local_ip_family = network_->GetBestIP().family(); | 
 |     if (server_ip_family != AF_UNSPEC && server_ip_family != local_ip_family) { | 
 |       RTC_LOG(LS_INFO) | 
 |           << "Server and local address families are not compatible. " | 
 |              "Server address: " | 
 |           << relay_port->address.ipaddr().ToSensitiveString() | 
 |           << " Local address: " << network_->GetBestIP().ToSensitiveString(); | 
 |       continue; | 
 |     } | 
 |  | 
 |     CreateRelayPortArgs args = {.env = session_->allocator()->env()}; | 
 |     args.network_thread = session_->network_thread(); | 
 |     args.socket_factory = session_->socket_factory(); | 
 |     args.network = network_; | 
 |     args.username = session_->username(); | 
 |     args.password = session_->password(); | 
 |     args.server_address = &(*relay_port); | 
 |     args.config = &config; | 
 |     args.turn_customizer = session_->allocator()->turn_customizer(); | 
 |     args.relative_priority = relative_priority; | 
 |  | 
 |     std::unique_ptr<Port> port; | 
 |     // Shared socket mode must be enabled only for UDP based ports. Hence | 
 |     // don't pass shared socket for ports which will create TCP sockets. | 
 |     // TODO(mallinath) - Enable shared socket mode for TURN ports. Disabled | 
 |     // due to webrtc bug https://code.google.com/p/webrtc/issues/detail?id=3537 | 
 |     if (IsFlagSet(PORTALLOCATOR_ENABLE_SHARED_SOCKET) && | 
 |         relay_port->proto == PROTO_UDP && udp_socket_) { | 
 |       port = session_->allocator()->relay_port_factory()->Create( | 
 |           args, udp_socket_.get()); | 
 |  | 
 |       if (!port) { | 
 |         RTC_LOG(LS_WARNING) << "Failed to create relay port with " | 
 |                             << args.server_address->address.ToSensitiveString(); | 
 |         continue; | 
 |       } | 
 |  | 
 |       relay_ports_.push_back(port.get()); | 
 |       // Listen to the port destroyed signal, to allow AllocationSequence to | 
 |       // remove the entry from it's map. | 
 |       port->SubscribePortDestroyed( | 
 |           [this](PortInterface* port) { OnPortDestroyed(port); }); | 
 |  | 
 |     } else { | 
 |       port = session_->allocator()->relay_port_factory()->Create( | 
 |           args, session_->allocator()->min_port(), | 
 |           session_->allocator()->max_port()); | 
 |  | 
 |       if (!port) { | 
 |         RTC_LOG(LS_WARNING) << "Failed to create relay port with " | 
 |                             << args.server_address->address.ToSensitiveString(); | 
 |         continue; | 
 |       } | 
 |     } | 
 |     RTC_DCHECK(port != nullptr); | 
 |     port->SetIceTiebreaker(session_->allocator()->ice_tiebreaker()); | 
 |     session_->AddAllocatedPort(port.release(), this); | 
 |   } | 
 | } | 
 |  | 
 | void AllocationSequence::OnReadPacket(AsyncPacketSocket* socket, | 
 |                                       const ReceivedIpPacket& packet) { | 
 |   RTC_DCHECK(socket == udp_socket_.get()); | 
 |  | 
 |   bool turn_port_found = false; | 
 |  | 
 |   // Try to find the TurnPort that matches the remote address. Note that the | 
 |   // message could be a STUN binding response if the TURN server is also used as | 
 |   // a STUN server. We don't want to parse every message here to check if it is | 
 |   // a STUN binding response, so we pass the message to TurnPort regardless of | 
 |   // the message type. The TurnPort will just ignore the message since it will | 
 |   // not find any request by transaction ID. | 
 |   for (auto* port : relay_ports_) { | 
 |     if (port->CanHandleIncomingPacketsFrom(packet.source_address())) { | 
 |       if (port->HandleIncomingPacket(socket, packet)) { | 
 |         return; | 
 |       } | 
 |       turn_port_found = true; | 
 |     } | 
 |   } | 
 |  | 
 |   if (udp_port_) { | 
 |     const ServerAddresses& stun_servers = udp_port_->server_addresses(); | 
 |  | 
 |     // Pass the packet to the UdpPort if there is no matching TurnPort, or if | 
 |     // the TURN server is also a STUN server. | 
 |     if (!turn_port_found || | 
 |         stun_servers.find(packet.source_address()) != stun_servers.end()) { | 
 |       RTC_DCHECK(udp_port_->SharedSocket()); | 
 |       udp_port_->HandleIncomingPacket(socket, packet); | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void AllocationSequence::OnPortDestroyed(PortInterface* port) { | 
 |   if (udp_port_ == port) { | 
 |     udp_port_ = nullptr; | 
 |     return; | 
 |   } | 
 |  | 
 |   auto it = absl::c_find(relay_ports_, port); | 
 |   if (it != relay_ports_.end()) { | 
 |     relay_ports_.erase(it); | 
 |   } else { | 
 |     RTC_LOG(LS_ERROR) << "Unexpected OnPortDestroyed for nonexistent port."; | 
 |     RTC_DCHECK_NOTREACHED(); | 
 |   } | 
 | } | 
 |  | 
 | PortConfiguration::PortConfiguration(const ServerAddresses& stun_servers, | 
 |                                      absl::string_view username, | 
 |                                      absl::string_view password, | 
 |                                      const FieldTrialsView* field_trials) | 
 |     : stun_servers(stun_servers), username(username), password(password) { | 
 |   if (!stun_servers.empty()) | 
 |     stun_address = *(stun_servers.begin()); | 
 |   // Note that this won't change once the config is initialized. | 
 |   if (field_trials) { | 
 |     use_turn_server_as_stun_server_disabled = | 
 |         field_trials->IsDisabled("WebRTC-UseTurnServerAsStunServer"); | 
 |   } | 
 | } | 
 |  | 
 | ServerAddresses PortConfiguration::StunServers() { | 
 |   if (!stun_address.IsNil() && | 
 |       stun_servers.find(stun_address) == stun_servers.end()) { | 
 |     stun_servers.insert(stun_address); | 
 |   } | 
 |  | 
 |   if (!stun_servers.empty() && use_turn_server_as_stun_server_disabled) { | 
 |     return stun_servers; | 
 |   } | 
 |  | 
 |   // Every UDP TURN server should also be used as a STUN server if | 
 |   // use_turn_server_as_stun_server is not disabled or the stun servers are | 
 |   // empty. | 
 |   ServerAddresses turn_servers = GetRelayServerAddresses(PROTO_UDP); | 
 |   for (const SocketAddress& turn_server : turn_servers) { | 
 |     if (stun_servers.find(turn_server) == stun_servers.end()) { | 
 |       stun_servers.insert(turn_server); | 
 |     } | 
 |   } | 
 |   return stun_servers; | 
 | } | 
 |  | 
 | void PortConfiguration::AddRelay(const RelayServerConfig& config) { | 
 |   relays.push_back(config); | 
 | } | 
 |  | 
 | bool PortConfiguration::SupportsProtocol(const RelayServerConfig& relay, | 
 |                                          ProtocolType type) const { | 
 |   PortList::const_iterator relay_port; | 
 |   for (relay_port = relay.ports.begin(); relay_port != relay.ports.end(); | 
 |        ++relay_port) { | 
 |     if (relay_port->proto == type) | 
 |       return true; | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | bool PortConfiguration::SupportsProtocol(ProtocolType type) const { | 
 |   for (size_t i = 0; i < relays.size(); ++i) { | 
 |     if (SupportsProtocol(relays[i], type)) | 
 |       return true; | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | ServerAddresses PortConfiguration::GetRelayServerAddresses( | 
 |     ProtocolType type) const { | 
 |   ServerAddresses servers; | 
 |   for (size_t i = 0; i < relays.size(); ++i) { | 
 |     if (SupportsProtocol(relays[i], type)) { | 
 |       servers.insert(relays[i].ports.front().address); | 
 |     } | 
 |   } | 
 |   return servers; | 
 | } | 
 |  | 
 | }  // namespace webrtc |