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* 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 <map>
#include <memory>
#include <set>
#include <string>
#include <vector>
#include "webrtc/base/asyncpacketsocket.h"
#include "webrtc/base/checks.h"
#include "webrtc/base/network.h"
#include "webrtc/base/optional.h"
#include "webrtc/base/proxyinfo.h"
#include "webrtc/base/ratetracker.h"
#include "webrtc/base/sigslot.h"
#include "webrtc/base/socketaddress.h"
#include "webrtc/base/thread.h"
#include "webrtc/p2p/base/candidate.h"
#include "webrtc/p2p/base/candidatepairinterface.h"
#include "webrtc/p2p/base/jseptransport.h"
#include "webrtc/p2p/base/packetlossestimator.h"
#include "webrtc/p2p/base/packetsocketfactory.h"
#include "webrtc/p2p/base/portinterface.h"
#include "webrtc/p2p/base/stun.h"
#include "webrtc/p2p/base/stunrequest.h"
namespace cricket {
class Connection;
class ConnectionRequest;
extern const char LOCAL_PORT_TYPE[];
extern const char STUN_PORT_TYPE[];
extern const char PRFLX_PORT_TYPE[];
extern const char RELAY_PORT_TYPE[];
extern const char UDP_PROTOCOL_NAME[];
extern const char TCP_PROTOCOL_NAME[];
extern const char SSLTCP_PROTOCOL_NAME[];
extern const char TLS_PROTOCOL_NAME[];
// RFC 6544, TCP candidate encoding rules.
extern const int DISCARD_PORT;
extern const char TCPTYPE_ACTIVE_STR[];
extern const char TCPTYPE_PASSIVE_STR[];
extern const char TCPTYPE_SIMOPEN_STR[];
// The minimum time we will wait before destroying a connection after creating
// it.
static const int MIN_CONNECTION_LIFETIME = 10 * 1000; // 10 seconds.
// A connection will be declared dead if it has not received anything for this
// long.
static const int DEAD_CONNECTION_RECEIVE_TIMEOUT = 30 * 1000; // 30 seconds.
// The timeout duration when a connection does not receive anything.
static const int WEAK_CONNECTION_RECEIVE_TIMEOUT = 2500; // 2.5 seconds
// The length of time we wait before timing out writability on a connection.
static const int CONNECTION_WRITE_TIMEOUT = 15 * 1000; // 15 seconds
// The length of time we wait before we become unwritable.
static const int CONNECTION_WRITE_CONNECT_TIMEOUT = 5 * 1000; // 5 seconds
// This is the length of time that we wait for a ping response to come back.
// There is no harm to keep this value high other than a small amount
// of increased memory. But in some networks (2G),
// we observe up to 60s RTTs.
static const int CONNECTION_RESPONSE_TIMEOUT = 60 * 1000; // 60 seconds
// The number of pings that must fail to respond before we become unwritable.
static const uint32_t CONNECTION_WRITE_CONNECT_FAILURES = 5;
enum RelayType {
RELAY_GTURN, // Legacy google relay service.
RELAY_TURN // Standard (TURN) relay service.
enum IcePriorityValue {
// States are from RFC 5245.
enum class IceCandidatePairState {
WAITING = 0, // Check has not been performed, Waiting pair on CL.
IN_PROGRESS, // Check has been sent, transaction is in progress.
SUCCEEDED, // Check already done, produced a successful result.
FAILED, // Check for this connection failed.
// According to spec there should also be a frozen state, but nothing is ever
// frozen because we have not implemented ICE freezing logic.
const char* ProtoToString(ProtocolType proto);
bool StringToProto(const char* value, ProtocolType* proto);
struct ProtocolAddress {
rtc::SocketAddress address;
ProtocolType proto;
ProtocolAddress(const rtc::SocketAddress& a, ProtocolType p)
: address(a), proto(p) {}
bool operator==(const ProtocolAddress& o) const {
return address == o.address && proto == o.proto;
bool operator!=(const ProtocolAddress& o) const { return !(*this == o); }
typedef std::set<rtc::SocketAddress> ServerAddresses;
// Represents a local communication mechanism that can be used to create
// connections to similar mechanisms of the other client. Subclasses of this
// one add support for specific mechanisms like local UDP ports.
class Port : public PortInterface, public rtc::MessageHandler,
public sigslot::has_slots<> {
// INIT: The state when a port is just created.
// KEEP_ALIVE_UNTIL_PRUNED: A port should not be destroyed even if no
// connection is using it.
// PRUNED: It will be destroyed if no connection is using it for a period of
// 30 seconds.
Port(rtc::Thread* thread,
const std::string& type,
rtc::PacketSocketFactory* factory,
rtc::Network* network,
const rtc::IPAddress& ip,
const std::string& username_fragment,
const std::string& password);
Port(rtc::Thread* thread,
const std::string& type,
rtc::PacketSocketFactory* factory,
rtc::Network* network,
const rtc::IPAddress& ip,
uint16_t min_port,
uint16_t max_port,
const std::string& username_fragment,
const std::string& password);
virtual ~Port();
virtual const std::string& Type() const { return type_; }
virtual rtc::Network* Network() const { return network_; }
// Methods to set/get ICE role and tiebreaker values.
IceRole GetIceRole() const { return ice_role_; }
void SetIceRole(IceRole role) { ice_role_ = role; }
void SetIceTiebreaker(uint64_t tiebreaker) { tiebreaker_ = tiebreaker; }
uint64_t IceTiebreaker() const { return tiebreaker_; }
virtual bool SharedSocket() const { return shared_socket_; }
void ResetSharedSocket() { shared_socket_ = false; }
// Should not destroy the port even if no connection is using it. Called when
// a port is ready to use.
void KeepAliveUntilPruned();
// Allows a port to be destroyed if no connection is using it.
void Prune();
// The thread on which this port performs its I/O.
rtc::Thread* thread() { return thread_; }
// The factory used to create the sockets of this port.
rtc::PacketSocketFactory* socket_factory() const { return factory_; }
void set_socket_factory(rtc::PacketSocketFactory* factory) {
factory_ = factory;
// For debugging purposes.
const std::string& content_name() const { return content_name_; }
void set_content_name(const std::string& content_name) {
content_name_ = content_name;
int component() const { return component_; }
void set_component(int component) { component_ = component; }
bool send_retransmit_count_attribute() const {
return send_retransmit_count_attribute_;
void set_send_retransmit_count_attribute(bool enable) {
send_retransmit_count_attribute_ = enable;
// Identifies the generation that this port was created in.
uint32_t generation() const { return generation_; }
void set_generation(uint32_t generation) { generation_ = generation; }
const std::string username_fragment() const;
const std::string& password() const { return password_; }
// May be called when this port was initially created by a pooled
// PortAllocatorSession, and is now being assigned to an ICE transport.
// Updates the information for candidates as well.
void SetIceParameters(int component,
const std::string& username_fragment,
const std::string& password);
// Fired when candidates are discovered by the port. When all candidates
// are discovered that belong to port SignalAddressReady is fired.
sigslot::signal2<Port*, const Candidate&> SignalCandidateReady;
// Provides all of the above information in one handy object.
virtual const std::vector<Candidate>& Candidates() const {
return candidates_;
// SignalPortComplete is sent when port completes the task of candidates
// allocation.
sigslot::signal1<Port*> SignalPortComplete;
// This signal sent when port fails to allocate candidates and this port
// can't be used in establishing the connections. When port is in shared mode
// and port fails to allocate one of the candidates, port shouldn't send
// this signal as other candidates might be usefull in establishing the
// connection.
sigslot::signal1<Port*> SignalPortError;
// Returns a map containing all of the connections of this port, keyed by the
// remote address.
typedef std::map<rtc::SocketAddress, Connection*> AddressMap;
const AddressMap& connections() { return connections_; }
// Returns the connection to the given address or NULL if none exists.
virtual Connection* GetConnection(
const rtc::SocketAddress& remote_addr);
// Called each time a connection is created.
sigslot::signal2<Port*, Connection*> SignalConnectionCreated;
// In a shared socket mode each port which shares the socket will decide
// to accept the packet based on the |remote_addr|. Currently only UDP
// port implemented this method.
// TODO(mallinath) - Make it pure virtual.
virtual bool HandleIncomingPacket(
rtc::AsyncPacketSocket* socket, const char* data, size_t size,
const rtc::SocketAddress& remote_addr,
const rtc::PacketTime& packet_time) {
return false;
// Sends a response message (normal or error) to the given request. One of
// these methods should be called as a response to SignalUnknownAddress.
// NOTE: You MUST call CreateConnection BEFORE SendBindingResponse.
virtual void SendBindingResponse(StunMessage* request,
const rtc::SocketAddress& addr);
virtual void SendBindingErrorResponse(
StunMessage* request, const rtc::SocketAddress& addr,
int error_code, const std::string& reason);
void set_proxy(const std::string& user_agent,
const rtc::ProxyInfo& proxy) {
user_agent_ = user_agent;
proxy_ = proxy;
const std::string& user_agent() { return user_agent_; }
const rtc::ProxyInfo& proxy() { return proxy_; }
virtual void EnablePortPackets();
// Called if the port has no connections and is no longer useful.
void Destroy();
virtual void OnMessage(rtc::Message *pmsg);
// Debugging description of this port
virtual std::string ToString() const;
const rtc::IPAddress& ip() const { return ip_; }
uint16_t min_port() { return min_port_; }
uint16_t max_port() { return max_port_; }
// Timeout shortening function to speed up unit tests.
void set_timeout_delay(int delay) { timeout_delay_ = delay; }
// This method will return local and remote username fragements from the
// stun username attribute if present.
bool ParseStunUsername(const StunMessage* stun_msg,
std::string* local_username,
std::string* remote_username) const;
void CreateStunUsername(const std::string& remote_username,
std::string* stun_username_attr_str) const;
bool MaybeIceRoleConflict(const rtc::SocketAddress& addr,
IceMessage* stun_msg,
const std::string& remote_ufrag);
// Called when a packet has been sent to the socket.
// This is made pure virtual to notify subclasses of Port that they MUST
// listen to AsyncPacketSocket::SignalSentPacket and then call
// PortInterface::OnSentPacket.
virtual void OnSentPacket(rtc::AsyncPacketSocket* socket,
const rtc::SentPacket& sent_packet) = 0;
// Called when the socket is currently able to send.
void OnReadyToSend();
// Called when the Connection discovers a local peer reflexive candidate.
// Returns the index of the new local candidate.
size_t AddPrflxCandidate(const Candidate& local);
int16_t network_cost() const { return network_cost_; }
virtual void UpdateNetworkCost();
void set_type(const std::string& type) { type_ = type; }
// Deprecated. Use the AddAddress() method below with "url" instead.
// TODO(zhihuang): Remove this after downstream applications stop using it.
void AddAddress(const rtc::SocketAddress& address,
const rtc::SocketAddress& base_address,
const rtc::SocketAddress& related_address,
const std::string& protocol,
const std::string& relay_protocol,
const std::string& tcptype,
const std::string& type,
uint32_t type_preference,
uint32_t relay_preference,
bool final);
void AddAddress(const rtc::SocketAddress& address,
const rtc::SocketAddress& base_address,
const rtc::SocketAddress& related_address,
const std::string& protocol,
const std::string& relay_protocol,
const std::string& tcptype,
const std::string& type,
uint32_t type_preference,
uint32_t relay_preference,
const std::string& url,
bool final);
// Adds the given connection to the map keyed by the remote candidate address.
// If an existing connection has the same address, the existing one will be
// replaced and destroyed.
void AddOrReplaceConnection(Connection* conn);
// Called when a packet is received from an unknown address that is not
// currently a connection. If this is an authenticated STUN binding request,
// then we will signal the client.
void OnReadPacket(const char* data, size_t size,
const rtc::SocketAddress& addr,
ProtocolType proto);
// If the given data comprises a complete and correct STUN message then the
// return value is true, otherwise false. If the message username corresponds
// with this port's username fragment, msg will contain the parsed STUN
// message. Otherwise, the function may send a STUN response internally.
// remote_username contains the remote fragment of the STUN username.
bool GetStunMessage(const char* data,
size_t size,
const rtc::SocketAddress& addr,
std::unique_ptr<IceMessage>* out_msg,
std::string* out_username);
// Checks if the address in addr is compatible with the port's ip.
bool IsCompatibleAddress(const rtc::SocketAddress& addr);
// Returns default DSCP value.
rtc::DiffServCodePoint DefaultDscpValue() const {
// No change from what MediaChannel set.
return rtc::DSCP_NO_CHANGE;
// Extra work to be done in subclasses when a connection is destroyed.
virtual void HandleConnectionDestroyed(Connection* conn) {}
void Construct();
// Called when one of our connections deletes itself.
void OnConnectionDestroyed(Connection* conn);
void OnNetworkTypeChanged(const rtc::Network* network);
rtc::Thread* thread_;
rtc::PacketSocketFactory* factory_;
std::string type_;
bool send_retransmit_count_attribute_;
rtc::Network* network_;
rtc::IPAddress ip_;
uint16_t min_port_;
uint16_t max_port_;
std::string content_name_;
int component_;
uint32_t generation_;
// In order to establish a connection to this Port (so that real data can be
// sent through), the other side must send us a STUN binding request that is
// authenticated with this username_fragment and password.
// PortAllocatorSession will provide these username_fragment and password.
// Note: we should always use username_fragment() instead of using
// |ice_username_fragment_| directly. For the details see the comment on
// username_fragment().
std::string ice_username_fragment_;
std::string password_;
std::vector<Candidate> candidates_;
AddressMap connections_;
int timeout_delay_;
bool enable_port_packets_;
IceRole ice_role_;
uint64_t tiebreaker_;
bool shared_socket_;
// Information to use when going through a proxy.
std::string user_agent_;
rtc::ProxyInfo proxy_;
// A virtual cost perceived by the user, usually based on the network type
// (WiFi. vs. Cellular). It takes precedence over the priority when
// comparing two connections.
uint16_t network_cost_;
State state_ = State::INIT;
int64_t last_time_all_connections_removed_ = 0;
friend class Connection;
// Represents a communication link between a port on the local client and a
// port on the remote client.
class Connection : public CandidatePairInterface,
public rtc::MessageHandler,
public sigslot::has_slots<> {
struct SentPing {
SentPing(const std::string id, int64_t sent_time, uint32_t nomination)
: id(id), sent_time(sent_time), nomination(nomination) {}
std::string id;
int64_t sent_time;
uint32_t nomination;
virtual ~Connection();
// The local port where this connection sends and receives packets.
Port* port() { return port_; }
const Port* port() const { return port_; }
// Implementation of virtual methods in CandidatePairInterface.
// Returns the description of the local port
virtual const Candidate& local_candidate() const;
// Returns the description of the remote port to which we communicate.
virtual const Candidate& remote_candidate() const;
// Returns the pair priority.
uint64_t priority() const;
enum WriteState {
STATE_WRITABLE = 0, // we have received ping responses recently
STATE_WRITE_UNRELIABLE = 1, // we have had a few ping failures
STATE_WRITE_INIT = 2, // we have yet to receive a ping response
STATE_WRITE_TIMEOUT = 3, // we have had a large number of ping failures
WriteState write_state() const { return write_state_; }
bool writable() const { return write_state_ == STATE_WRITABLE; }
bool receiving() const { return receiving_; }
// Determines whether the connection has finished connecting. This can only
// be false for TCP connections.
bool connected() const { return connected_; }
bool weak() const { return !(writable() && receiving() && connected()); }
bool active() const {
return write_state_ != STATE_WRITE_TIMEOUT;
// A connection is dead if it can be safely deleted.
bool dead(int64_t now) const;
// Estimate of the round-trip time over this connection.
int rtt() const { return rtt_; }
// Gets the |ConnectionInfo| stats, where |best_connection| has not been
// populated (default value false).
ConnectionInfo stats();
sigslot::signal1<Connection*> SignalStateChange;
// Sent when the connection has decided that it is no longer of value. It
// will delete itself immediately after this call.
sigslot::signal1<Connection*> SignalDestroyed;
// The connection can send and receive packets asynchronously. This matches
// the interface of AsyncPacketSocket, which may use UDP or TCP under the
// covers.
virtual int Send(const void* data, size_t size,
const rtc::PacketOptions& options) = 0;
// Error if Send() returns < 0
virtual int GetError() = 0;
sigslot::signal4<Connection*, const char*, size_t, const rtc::PacketTime&>
sigslot::signal1<Connection*> SignalReadyToSend;
// Called when a packet is received on this connection.
void OnReadPacket(const char* data, size_t size,
const rtc::PacketTime& packet_time);
// Called when the socket is currently able to send.
void OnReadyToSend();
// Called when a connection is determined to be no longer useful to us. We
// still keep it around in case the other side wants to use it. But we can
// safely stop pinging on it and we can allow it to time out if the other
// side stops using it as well.
bool pruned() const { return pruned_; }
void Prune();
bool use_candidate_attr() const { return use_candidate_attr_; }
void set_use_candidate_attr(bool enable);
void set_nomination(uint32_t value) { nomination_ = value; }
uint32_t remote_nomination() const { return remote_nomination_; }
// One or several pairs may be nominated based on if Regular or Aggressive
// Nomination is used.
// |nominated| is defined both for the controlling or controlled agent based
// on if a nomination has been pinged or acknowledged. The controlled agent
// gets its |remote_nomination_| set when pinged by the controlling agent with
// a nomination value. The controlling agent gets its |acked_nomination_| set
// when receiving a response to a nominating ping.
bool nominated() const { return acked_nomination_ || remote_nomination_; }
// Public for unit tests.
void set_remote_nomination(uint32_t remote_nomination) {
remote_nomination_ = remote_nomination;
// Public for unit tests.
uint32_t acked_nomination() const { return acked_nomination_; }
void set_remote_ice_mode(IceMode mode) {
remote_ice_mode_ = mode;
void set_receiving_timeout(int receiving_timeout_ms) {
receiving_timeout_ = receiving_timeout_ms;
// Makes the connection go away.
void Destroy();
// Makes the connection go away, in a failed state.
void FailAndDestroy();
// Prunes the connection and sets its state to STATE_FAILED,
// It will not be used or send pings although it can still receive packets.
void FailAndPrune();
// Checks that the state of this connection is up-to-date. The argument is
// the current time, which is compared against various timeouts.
void UpdateState(int64_t now);
// 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, const std::string& request_id);
int64_t last_ping_response_received() const {
return last_ping_response_received_;
// Used to check if any STUN ping response has been received.
int rtt_samples() const { return rtt_samples_; }
// Called whenever a valid ping is received on this connection. This is
// public because the connection intercepts the first ping for us.
int64_t last_ping_received() const { return last_ping_received_; }
void ReceivedPing();
// Handles the binding request; sends a response if this is a valid request.
void HandleBindingRequest(IceMessage* msg);
int64_t last_data_received() const { return last_data_received_; }
// Debugging description of this connection
std::string ToDebugId() const;
std::string ToString() const;
std::string ToSensitiveString() const;
// Prints pings_since_last_response_ into a string.
void PrintPingsSinceLastResponse(std::string* pings, size_t max);
bool reported() const { return reported_; }
void set_reported(bool reported) { reported_ = reported;}
// This signal will be fired if this connection is nominated by the
// controlling side.
sigslot::signal1<Connection*> SignalNominated;
// Invoked when Connection receives STUN error response with 487 code.
void HandleRoleConflictFromPeer();
IceCandidatePairState state() const { return state_; }
int num_pings_sent() const { return num_pings_sent_; }
IceMode remote_ice_mode() const { return remote_ice_mode_; }
uint32_t ComputeNetworkCost() const;
// Update the ICE password and/or generation of the remote candidate if the
// ufrag in |params| matches the candidate's ufrag, and the
// candidate's password and/or ufrag has not been set.
void MaybeSetRemoteIceParametersAndGeneration(const IceParameters& params,
int generation);
// If |remote_candidate_| is peer reflexive and is equivalent to
// |new_candidate| except the type, update |remote_candidate_| to
// |new_candidate|.
void MaybeUpdatePeerReflexiveCandidate(const Candidate& new_candidate);
// Returns the last received time of any data, stun request, or stun
// response in milliseconds
int64_t last_received() const;
// Returns the last time when the connection changed its receiving state.
int64_t receiving_unchanged_since() const {
return receiving_unchanged_since_;
bool stable(int64_t now) const;
// Constructs a new connection to the given remote port.
Connection(Port* port, size_t index, const Candidate& candidate);
// Called back when StunRequestManager has a stun packet to send
void OnSendStunPacket(const void* data, size_t size, StunRequest* req);
// Callbacks from ConnectionRequest
virtual void OnConnectionRequestResponse(ConnectionRequest* req,
StunMessage* response);
void OnConnectionRequestErrorResponse(ConnectionRequest* req,
StunMessage* response);
void OnConnectionRequestTimeout(ConnectionRequest* req);
void OnConnectionRequestSent(ConnectionRequest* req);
bool rtt_converged() const;
// If the response is not received within 2 * RTT, the response is assumed to
// be missing.
bool missing_responses(int64_t now) const;
// Changes the state and signals if necessary.
void set_write_state(WriteState value);
void UpdateReceiving(int64_t now);
void set_state(IceCandidatePairState state);
void set_connected(bool value);
uint32_t nomination() const { return nomination_; }
void OnMessage(rtc::Message *pmsg);
Port* port_;
size_t local_candidate_index_;
Candidate remote_candidate_;
ConnectionInfo stats_;
rtc::RateTracker recv_rate_tracker_;
rtc::RateTracker send_rate_tracker_;
// Update the local candidate based on the mapped address attribute.
// If the local candidate changed, fires SignalStateChange.
void MaybeUpdateLocalCandidate(ConnectionRequest* request,
StunMessage* response);
WriteState write_state_;
bool receiving_;
bool connected_;
bool pruned_;
// By default |use_candidate_attr_| flag will be true,
// as we will be using aggressive nomination.
// 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_;
// Used by the controlling side to indicate that this connection will be
// selected for transmission if the peer supports ICE-renomination when 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.
// A zero-value indicates not nominating this connection.
uint32_t nomination_ = 0;
// The last nomination that has been acknowledged.
uint32_t acked_nomination_ = 0;
// 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 has been nominated.
uint32_t remote_nomination_ = 0;
IceMode remote_ice_mode_;
StunRequestManager requests_;
int rtt_;
int rtt_samples_ = 0;
uint64_t total_round_trip_time_ms_ = 0;
rtc::Optional<uint32_t> current_round_trip_time_ms_;
int64_t last_ping_sent_; // last time we sent a ping to the other side
int64_t last_ping_received_; // last time we received a ping from the other
// side
int64_t last_data_received_;
int64_t last_ping_response_received_;
int64_t receiving_unchanged_since_ = 0;
std::vector<SentPing> pings_since_last_response_;
PacketLossEstimator packet_loss_estimator_;
bool reported_;
IceCandidatePairState state_;
// Time duration to switch from receiving to not receiving.
int receiving_timeout_;
int64_t time_created_ms_;
int num_pings_sent_ = 0;
friend class Port;
friend class ConnectionRequest;
// ProxyConnection defers all the interesting work to the port.
class ProxyConnection : public Connection {
ProxyConnection(Port* port, size_t index, const Candidate& remote_candidate);
int Send(const void* data,
size_t size,
const rtc::PacketOptions& options) override;
int GetError() override { return error_; }
int error_ = 0;
} // namespace cricket