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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.
#ifndef P2P_BASE_PORT_H_
#define P2P_BASE_PORT_H_
#include <map>
#include <memory>
#include <set>
#include <string>
#include <utility>
#include <vector>
#include "absl/types/optional.h"
#include "api/candidate.h"
#include "api/packet_socket_factory.h"
#include "api/rtc_error.h"
#include "api/transport/stun.h"
#include "logging/rtc_event_log/events/rtc_event_ice_candidate_pair.h"
#include "logging/rtc_event_log/events/rtc_event_ice_candidate_pair_config.h"
#include "logging/rtc_event_log/ice_logger.h"
#include "p2p/base/candidate_pair_interface.h"
#include "p2p/base/connection.h"
#include "p2p/base/connection_info.h"
#include "p2p/base/p2p_constants.h"
#include "p2p/base/port_interface.h"
#include "p2p/base/stun_request.h"
#include "rtc_base/async_packet_socket.h"
#include "rtc_base/checks.h"
#include "rtc_base/net_helper.h"
#include "rtc_base/network.h"
#include "rtc_base/proxy_info.h"
#include "rtc_base/rate_tracker.h"
#include "rtc_base/socket_address.h"
#include "rtc_base/system/rtc_export.h"
#include "rtc_base/third_party/sigslot/sigslot.h"
#include "rtc_base/thread.h"
#include "rtc_base/weak_ptr.h"
namespace cricket {
RTC_EXPORT extern const char LOCAL_PORT_TYPE[];
RTC_EXPORT extern const char STUN_PORT_TYPE[];
RTC_EXPORT extern const char PRFLX_PORT_TYPE[];
RTC_EXPORT extern const char RELAY_PORT_TYPE[];
// 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[];
enum IcePriorityValue {
enum class MdnsNameRegistrationStatus {
// IP concealment with mDNS is not enabled or the name registration process is
// not started yet.
// A request to create and register an mDNS name for a local IP address of a
// host candidate is sent to the mDNS responder.
// The name registration is complete and the created name is returned by the
// mDNS responder.
// Stats that we can return about the port of a STUN candidate.
class StunStats {
StunStats() = default;
StunStats(const StunStats&) = default;
~StunStats() = default;
StunStats& operator=(const StunStats& other) = default;
int stun_binding_requests_sent = 0;
int stun_binding_responses_received = 0;
double stun_binding_rtt_ms_total = 0;
double stun_binding_rtt_ms_squared_total = 0;
// Stats that we can return about a candidate.
class CandidateStats {
explicit CandidateStats(Candidate candidate);
CandidateStats(const CandidateStats&);
Candidate candidate;
// STUN port stats if this candidate is a STUN candidate.
absl::optional<StunStats> stun_stats;
typedef std::vector<CandidateStats> CandidateStatsList;
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); }
struct IceCandidateErrorEvent {
IceCandidateErrorEvent() = default;
IceCandidateErrorEvent(std::string address,
int port,
std::string url,
int error_code,
std::string error_text)
: address(std::move(address)),
error_text(std::move(error_text)) {}
std::string address;
int port = 0;
std::string url;
int error_code = 0;
std::string error_text;
struct CandidatePairChangeEvent {
CandidatePair selected_candidate_pair;
int64_t last_data_received_ms;
std::string reason;
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 std::string& username_fragment,
const std::string& password);
Port(rtc::Thread* thread,
const std::string& type,
rtc::PacketSocketFactory* factory,
rtc::Network* network,
uint16_t min_port,
uint16_t max_port,
const std::string& username_fragment,
const std::string& password);
~Port() override;
// Note that the port type does NOT uniquely identify different subclasses of
// Port. Use the 2-tuple of the port type AND the protocol (GetProtocol()) to
// uniquely identify subclasses. Whenever a new subclass of Port introduces a
// conflit in the value of the 2-tuple, make sure that the implementation that
// relies on this 2-tuple for RTTI is properly changed.
const std::string& Type() const override;
rtc::Network* Network() const override;
// Methods to set/get ICE role and tiebreaker values.
IceRole GetIceRole() const override;
void SetIceRole(IceRole role) override;
void SetIceTiebreaker(uint64_t tiebreaker) override;
uint64_t IceTiebreaker() const override;
bool SharedSocket() const override;
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.
const std::vector<Candidate>& Candidates() const override;
// Fired when candidate discovery failed using certain server.
sigslot::signal2<Port*, const IceCandidateErrorEvent&> SignalCandidateError;
// 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.
Connection* GetConnection(const rtc::SocketAddress& remote_addr) override;
// 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,
int64_t packet_time_us);
// Shall the port handle packet from this |remote_addr|.
// This method is overridden by TurnPort.
virtual bool CanHandleIncomingPacketsFrom(
const rtc::SocketAddress& remote_addr) const;
// Sends a response error to the given request.
void SendBindingErrorResponse(StunMessage* request,
const rtc::SocketAddress& addr,
int error_code,
const std::string& reason) override;
void SendUnknownAttributesErrorResponse(
StunMessage* request,
const rtc::SocketAddress& addr,
const std::vector<uint16_t>& unknown_types);
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_; }
void EnablePortPackets() override;
// Called if the port has no connections and is no longer useful.
void Destroy();
void OnMessage(rtc::Message* pmsg) override;
// Debugging description of this port
std::string ToString() const override;
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_; }
void GetStunStats(absl::optional<StunStats>* stats) override {}
// Foundation: An arbitrary string that is the same for two candidates
// that have the same type, base IP address, protocol (UDP, TCP,
// etc.), and STUN or TURN server. If any of these are different,
// then the foundation will be different. Two candidate pairs with
// the same foundation pairs are likely to have similar network
// characteristics. Foundations are used in the frozen algorithm.
static std::string ComputeFoundation(const std::string& type,
const std::string& protocol,
const std::string& relay_protocol,
const rtc::SocketAddress& base_address);
virtual void UpdateNetworkCost();
void set_type(const std::string& type) { type_ = type; }
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 is_final);
void FinishAddingAddress(const Candidate& c, bool is_final);
virtual void PostAddAddress(bool is_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 DSCP value packets generated by the port itself should use.
virtual rtc::DiffServCodePoint StunDscpValue() const;
// Extra work to be done in subclasses when a connection is destroyed.
virtual void HandleConnectionDestroyed(Connection* conn) {}
void CopyPortInformationToPacketInfo(rtc::PacketInfo* info) const;
MdnsNameRegistrationStatus mdns_name_registration_status() const {
return mdns_name_registration_status_;
void set_mdns_name_registration_status(MdnsNameRegistrationStatus status) {
mdns_name_registration_status_ = status;
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_;
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.
int16_t network_cost_;
State state_ = State::INIT;
int64_t last_time_all_connections_removed_ = 0;
MdnsNameRegistrationStatus mdns_name_registration_status_ =
rtc::WeakPtrFactory<Port> weak_factory_;
bool MaybeObfuscateAddress(Candidate* c,
const std::string& type,
bool is_final);
friend class Connection;
} // namespace cricket
#endif // P2P_BASE_PORT_H_