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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.
*/
/*
* This is a diagram of how TCP reconnect works for the active side. The
* passive side just waits for an incoming connection.
*
* - Connected: Indicate whether the TCP socket is connected.
*
* - Writable: Whether the stun binding is completed. Sending a data packet
* before stun binding completed will trigger IPC socket layer to shutdown
* the connection.
*
* - PendingTCP: `connection_pending_` indicates whether there is an
* outstanding TCP connection in progress.
*
* - PretendWri: Tracked by `pretending_to_be_writable_`. Marking connection as
* WRITE_TIMEOUT will cause the connection be deleted. Instead, we're
* "pretending" we're still writable for a period of time such that reconnect
* could work.
*
* Data could only be sent in state 3. Sening data during state 2 & 6 will get
* EWOULDBLOCK, 4 & 5 EPIPE.
*
* OS Timeout 7 -------------+
* +----------------------->|Connected: N |
* | |Writable: N | Timeout
* | Timeout |Connection is |<----------------+
* | +------------------->|Dead | |
* | | +--------------+ |
* | | ^ |
* | | OnClose | |
* | | +-----------------------+ | |
* | | | | |Timeout |
* | | v | | |
* | 4 +----------+ 5 -----+--+--+ 6 -----+-----+
* | |Connected: N|Send() or |Connected: N| |Connected: Y|
* | |Writable: Y|Ping() |Writable: Y|OnConnect |Writable: Y|
* | |PendingTCP:N+--------> |PendingTCP:Y+---------> |PendingTCP:N|
* | |PretendWri:Y| |PretendWri:Y| |PretendWri:Y|
* | +-----+------+ +------------+ +---+--+-----+
* | ^ ^ | |
* | | | OnClose | |
* | | +----------------------------------------------+ |
* | | |
* | | Stun Binding Completed |
* | | |
* | | OnClose |
* | +------------------------------------------------+ |
* | | v
* 1 -----------+ 2 -----------+Stun 3 -----------+
* |Connected: N| |Connected: Y|Binding |Connected: Y|
* |Writable: N|OnConnect |Writable: N|Completed |Writable: Y|
* |PendingTCP:Y+---------> |PendingTCP:N+--------> |PendingTCP:N|
* |PretendWri:N| |PretendWri:N| |PretendWri:N|
* +------------+ +------------+ +------------+
*
*/
#include "p2p/base/tcp_port.h"
#include <errno.h>
#include <utility>
#include <vector>
#include "absl/algorithm/container.h"
#include "absl/memory/memory.h"
#include "absl/strings/string_view.h"
#include "api/task_queue/pending_task_safety_flag.h"
#include "api/units/time_delta.h"
#include "p2p/base/p2p_constants.h"
#include "rtc_base/checks.h"
#include "rtc_base/ip_address.h"
#include "rtc_base/logging.h"
#include "rtc_base/net_helper.h"
#include "rtc_base/network/received_packet.h"
#include "rtc_base/rate_tracker.h"
#include "rtc_base/thread.h"
namespace cricket {
using ::webrtc::IceCandidateType;
using ::webrtc::SafeTask;
using ::webrtc::TimeDelta;
TCPPort::TCPPort(const PortParametersRef& args,
uint16_t min_port,
uint16_t max_port,
bool allow_listen)
: Port(args, IceCandidateType::kHost, min_port, max_port),
allow_listen_(allow_listen),
error_(0) {
// TODO(mallinath) - Set preference value as per RFC 6544.
if (allow_listen_) {
TryCreateServerSocket();
}
// Set TCP_NODELAY (via OPT_NODELAY) for improved performance; this causes
// small media packets to be sent immediately rather than being buffered up,
// reducing latency.
SetOption(rtc::Socket::OPT_NODELAY, 1);
}
TCPPort::~TCPPort() {
listen_socket_ = nullptr;
std::list<Incoming>::iterator it;
for (it = incoming_.begin(); it != incoming_.end(); ++it)
delete it->socket;
incoming_.clear();
}
Connection* TCPPort::CreateConnection(const Candidate& address,
CandidateOrigin origin) {
if (!SupportsProtocol(address.protocol())) {
return NULL;
}
if ((address.tcptype() == TCPTYPE_ACTIVE_STR && !address.is_prflx()) ||
(address.tcptype().empty() && address.address().port() == 0)) {
// It's active only candidate, we should not try to create connections
// for these candidates.
return NULL;
}
// We can't accept TCP connections incoming on other ports
if (origin == ORIGIN_OTHER_PORT)
return NULL;
// We don't know how to act as an ssl server yet
if ((address.protocol() == SSLTCP_PROTOCOL_NAME) &&
(origin == ORIGIN_THIS_PORT)) {
return NULL;
}
if (!IsCompatibleAddress(address.address())) {
return NULL;
}
TCPConnection* conn = NULL;
if (rtc::AsyncPacketSocket* socket = GetIncoming(address.address(), true)) {
// Incoming connection; we already created a socket and connected signals,
// so we need to hand off the "read packet" responsibility to
// TCPConnection.
socket->DeregisterReceivedPacketCallback();
conn = new TCPConnection(NewWeakPtr(), address, socket);
} else {
// Outgoing connection, which will create a new socket.
conn = new TCPConnection(NewWeakPtr(), address);
}
AddOrReplaceConnection(conn);
return conn;
}
void TCPPort::PrepareAddress() {
if (listen_socket_) {
// Socket may be in the CLOSED state if Listen()
// failed, we still want to add the socket address.
RTC_LOG(LS_VERBOSE) << "Preparing TCP address, current state: "
<< static_cast<int>(listen_socket_->GetState());
AddAddress(
listen_socket_->GetLocalAddress(), listen_socket_->GetLocalAddress(),
rtc::SocketAddress(), TCP_PROTOCOL_NAME, "", TCPTYPE_PASSIVE_STR,
IceCandidateType::kHost, ICE_TYPE_PREFERENCE_HOST_TCP, 0, "", true);
} else {
RTC_LOG(LS_INFO) << ToString()
<< ": Not listening due to firewall restrictions.";
// Note: We still add the address, since otherwise the remote side won't
// recognize our incoming TCP connections. According to
// the port must be set to the discard port, i.e. 9. We can't be 100% sure
// which IP address will actually be used, so GetBestIP is as good as we
// can do.
// TODO(deadbeef): We could do something like create a dummy socket just to
// see what IP we get. But that may be overkill.
AddAddress(rtc::SocketAddress(Network()->GetBestIP(), DISCARD_PORT),
rtc::SocketAddress(Network()->GetBestIP(), 0),
rtc::SocketAddress(), TCP_PROTOCOL_NAME, "", TCPTYPE_ACTIVE_STR,
IceCandidateType::kHost, ICE_TYPE_PREFERENCE_HOST_TCP, 0, "",
true);
}
}
int TCPPort::SendTo(const void* data,
size_t size,
const rtc::SocketAddress& addr,
const rtc::PacketOptions& options,
bool payload) {
rtc::AsyncPacketSocket* socket = NULL;
TCPConnection* conn = static_cast<TCPConnection*>(GetConnection(addr));
// For Connection, this is the code path used by Ping() to establish
// WRITABLE. It has to send through the socket directly as TCPConnection::Send
// checks writability.
if (conn) {
if (!conn->connected()) {
conn->MaybeReconnect();
return SOCKET_ERROR;
}
socket = conn->socket();
if (!socket) {
// The failure to initialize should have been logged elsewhere,
// so this log is not important.
RTC_LOG(LS_INFO) << ToString()
<< ": Attempted to send to an uninitialized socket: "
<< addr.ToSensitiveString();
error_ = EHOSTUNREACH;
return SOCKET_ERROR;
}
} else {
socket = GetIncoming(addr);
if (!socket) {
RTC_LOG(LS_ERROR) << ToString()
<< ": Attempted to send to an unknown destination: "
<< addr.ToSensitiveString();
error_ = EHOSTUNREACH;
return SOCKET_ERROR;
}
}
rtc::PacketOptions modified_options(options);
CopyPortInformationToPacketInfo(&modified_options.info_signaled_after_sent);
int sent = socket->Send(data, size, modified_options);
if (sent < 0) {
error_ = socket->GetError();
// Error from this code path for a Connection (instead of from a bare
// socket) will not trigger reconnecting. In theory, this shouldn't matter
// as OnClose should always be called and set connected to false.
RTC_LOG(LS_ERROR) << ToString() << ": TCP send of " << size
<< " bytes failed with error " << error_;
}
return sent;
}
int TCPPort::GetOption(rtc::Socket::Option opt, int* value) {
auto const& it = socket_options_.find(opt);
if (it == socket_options_.end()) {
return -1;
}
*value = it->second;
return 0;
}
int TCPPort::SetOption(rtc::Socket::Option opt, int value) {
socket_options_[opt] = value;
return 0;
}
int TCPPort::GetError() {
return error_;
}
bool TCPPort::SupportsProtocol(absl::string_view protocol) const {
return protocol == TCP_PROTOCOL_NAME || protocol == SSLTCP_PROTOCOL_NAME;
}
ProtocolType TCPPort::GetProtocol() const {
return PROTO_TCP;
}
void TCPPort::OnNewConnection(rtc::AsyncListenSocket* socket,
rtc::AsyncPacketSocket* new_socket) {
RTC_DCHECK_EQ(socket, listen_socket_.get());
for (const auto& option : socket_options_) {
new_socket->SetOption(option.first, option.second);
}
Incoming incoming;
incoming.addr = new_socket->GetRemoteAddress();
incoming.socket = new_socket;
incoming.socket->RegisterReceivedPacketCallback(
[&](rtc::AsyncPacketSocket* socket, const rtc::ReceivedPacket& packet) {
OnReadPacket(socket, packet);
});
incoming.socket->SignalReadyToSend.connect(this, &TCPPort::OnReadyToSend);
incoming.socket->SignalSentPacket.connect(this, &TCPPort::OnSentPacket);
RTC_LOG(LS_VERBOSE) << ToString() << ": Accepted connection from "
<< incoming.addr.ToSensitiveString();
incoming_.push_back(incoming);
}
void TCPPort::TryCreateServerSocket() {
listen_socket_ = absl::WrapUnique(socket_factory()->CreateServerTcpSocket(
rtc::SocketAddress(Network()->GetBestIP(), 0), min_port(), max_port(),
false /* ssl */));
if (!listen_socket_) {
RTC_LOG(LS_WARNING)
<< ToString()
<< ": TCP server socket creation failed; continuing anyway.";
return;
}
listen_socket_->SignalNewConnection.connect(this, &TCPPort::OnNewConnection);
}
rtc::AsyncPacketSocket* TCPPort::GetIncoming(const rtc::SocketAddress& addr,
bool remove) {
rtc::AsyncPacketSocket* socket = NULL;
for (std::list<Incoming>::iterator it = incoming_.begin();
it != incoming_.end(); ++it) {
if (it->addr == addr) {
socket = it->socket;
if (remove)
incoming_.erase(it);
break;
}
}
return socket;
}
void TCPPort::OnReadPacket(rtc::AsyncPacketSocket* socket,
const rtc::ReceivedPacket& packet) {
Port::OnReadPacket(packet, PROTO_TCP);
}
void TCPPort::OnSentPacket(rtc::AsyncPacketSocket* socket,
const rtc::SentPacket& sent_packet) {
PortInterface::SignalSentPacket(sent_packet);
}
void TCPPort::OnReadyToSend(rtc::AsyncPacketSocket* socket) {
Port::OnReadyToSend();
}
// TODO(qingsi): `CONNECTION_WRITE_CONNECT_TIMEOUT` is overriden by
// `ice_unwritable_timeout` in IceConfig when determining the writability state.
// Replace this constant with the config parameter assuming the default value if
// we decide it is also applicable here.
TCPConnection::TCPConnection(rtc::WeakPtr<Port> tcp_port,
const Candidate& candidate,
rtc::AsyncPacketSocket* socket)
: Connection(std::move(tcp_port), 0, candidate),
socket_(socket),
error_(0),
outgoing_(socket == NULL),
connection_pending_(false),
pretending_to_be_writable_(false),
reconnection_timeout_(cricket::CONNECTION_WRITE_CONNECT_TIMEOUT) {
RTC_DCHECK_RUN_ON(network_thread_);
RTC_DCHECK_EQ(port()->GetProtocol(), PROTO_TCP); // Needs to be TCPPort.
SignalDestroyed.connect(this, &TCPConnection::OnDestroyed);
if (outgoing_) {
CreateOutgoingTcpSocket();
} else {
// Incoming connections should match one of the network addresses. Same as
// what's being checked in OnConnect, but just DCHECKing here.
RTC_LOG(LS_VERBOSE) << ToString() << ": socket ipaddr: "
<< socket_->GetLocalAddress().ToSensitiveString()
<< ", port() Network:" << port()->Network()->ToString();
RTC_DCHECK(absl::c_any_of(
port_->Network()->GetIPs(), [this](const rtc::InterfaceAddress& addr) {
return socket_->GetLocalAddress().ipaddr() == addr;
}));
ConnectSocketSignals(socket);
}
}
TCPConnection::~TCPConnection() {
RTC_DCHECK_RUN_ON(network_thread_);
}
int TCPConnection::Send(const void* data,
size_t size,
const rtc::PacketOptions& options) {
if (!socket_) {
error_ = ENOTCONN;
return SOCKET_ERROR;
}
// Sending after OnClose on active side will trigger a reconnect for a
// outgoing connection. Note that the write state is still WRITABLE as we want
// to spend a few seconds attempting a reconnect before saying we're
// unwritable.
if (!connected()) {
MaybeReconnect();
return SOCKET_ERROR;
}
// Note that this is important to put this after the previous check to give
// the connection a chance to reconnect.
if (pretending_to_be_writable_ || write_state() != STATE_WRITABLE) {
// TODO(?): Should STATE_WRITE_TIMEOUT return a non-blocking error?
error_ = ENOTCONN;
return SOCKET_ERROR;
}
stats_.sent_total_packets++;
rtc::PacketOptions modified_options(options);
tcp_port()->CopyPortInformationToPacketInfo(
&modified_options.info_signaled_after_sent);
int sent = socket_->Send(data, size, modified_options);
int64_t now = rtc::TimeMillis();
if (sent < 0) {
stats_.sent_discarded_packets++;
error_ = socket_->GetError();
} else {
send_rate_tracker_.AddSamplesAtTime(now, sent);
}
last_send_data_ = now;
return sent;
}
int TCPConnection::GetError() {
return error_;
}
void TCPConnection::OnSentPacket(rtc::AsyncPacketSocket* socket,
const rtc::SentPacket& sent_packet) {
RTC_DCHECK_RUN_ON(network_thread());
if (port()) {
port()->SignalSentPacket(sent_packet);
}
}
void TCPConnection::OnConnectionRequestResponse(StunRequest* req,
StunMessage* response) {
// Process the STUN response before we inform upper layer ready to send.
Connection::OnConnectionRequestResponse(req, response);
// If we're in the state of pretending to be writeable, we should inform the
// upper layer it's ready to send again as previous EWOULDLBLOCK from socket
// would have stopped the outgoing stream.
if (pretending_to_be_writable_) {
Connection::OnReadyToSend();
}
pretending_to_be_writable_ = false;
RTC_DCHECK(write_state() == STATE_WRITABLE);
}
void TCPConnection::OnConnect(rtc::AsyncPacketSocket* socket) {
RTC_DCHECK_EQ(socket, socket_.get());
if (!port_) {
RTC_LOG(LS_ERROR) << "TCPConnection: Port has been deleted.";
return;
}
// Do not use this port if the socket bound to an address not associated with
// the desired network interface. This is seen in Chrome, where TCP sockets
// cannot be given a binding address, and the platform is expected to pick
// the correct local address.
//
// However, there are two situations in which we allow the bound address to
// not be one of the addresses of the requested interface:
// 1. The bound address is the loopback address. This happens when a proxy
// forces TCP to bind to only the localhost address (see issue 3927).
// 2. The bound address is the "any address". This happens when
// multiple_routes is disabled (see issue 4780).
//
// Note that, aside from minor differences in log statements, this logic is
// identical to that in TurnPort.
const rtc::SocketAddress& socket_address = socket->GetLocalAddress();
if (absl::c_any_of(port_->Network()->GetIPs(),
[socket_address](const rtc::InterfaceAddress& addr) {
return socket_address.ipaddr() == addr;
})) {
RTC_LOG(LS_VERBOSE) << ToString() << ": Connection established to "
<< socket->GetRemoteAddress().ToSensitiveString();
} else {
if (socket->GetLocalAddress().IsLoopbackIP()) {
RTC_LOG(LS_WARNING) << "Socket is bound to the address:"
<< socket_address.ipaddr().ToSensitiveString()
<< ", rather than an address associated with network:"
<< port_->Network()->ToString()
<< ". Still allowing it since it's localhost.";
} else if (IPIsAny(port_->Network()->GetBestIP())) {
RTC_LOG(LS_WARNING)
<< "Socket is bound to the address:"
<< socket_address.ipaddr().ToSensitiveString()
<< ", rather than an address associated with network:"
<< port_->Network()->ToString()
<< ". Still allowing it since it's the 'any' address"
", possibly caused by multiple_routes being disabled.";
} else {
RTC_LOG(LS_WARNING) << "Dropping connection as TCP socket bound to IP "
<< socket_address.ipaddr().ToSensitiveString()
<< ", rather than an address associated with network:"
<< port_->Network()->ToString();
OnClose(socket, 0);
return;
}
}
// Connection is established successfully.
set_connected(true);
connection_pending_ = false;
}
void TCPConnection::OnClose(rtc::AsyncPacketSocket* socket, int error) {
RTC_DCHECK_RUN_ON(network_thread());
RTC_DCHECK_EQ(socket, socket_.get());
RTC_LOG(LS_INFO) << ToString() << ": Connection closed with error " << error;
if (!port_) {
RTC_LOG(LS_ERROR) << "TCPConnection: Port has been deleted.";
return;
}
// Guard against the condition where IPC socket will call OnClose for every
// packet it can't send.
if (connected()) {
set_connected(false);
// Prevent the connection from being destroyed by redundant SignalClose
// events.
pretending_to_be_writable_ = true;
// If this connection can't become connected and writable again in 5
// seconds, it's time to tear this down. This is the case for the original
// TCP connection on passive side during a reconnect.
// We don't attempt reconnect right here. This is to avoid a case where the
// shutdown is intentional and reconnect is not necessary. We only reconnect
// when the connection is used to Send() or Ping().
network_thread()->PostDelayedTask(
SafeTask(network_safety_.flag(),
[this]() {
if (pretending_to_be_writable_) {
Destroy();
}
}),
TimeDelta::Millis(reconnection_timeout()));
} else if (!pretending_to_be_writable_) {
// OnClose could be called when the underneath socket times out during the
// initial connect() (i.e. `pretending_to_be_writable_` is false) . We have
// to manually destroy here as this connection, as never connected, will not
// be scheduled for ping to trigger destroy.
DisconnectSocketSignals(socket_.get());
port()->DestroyConnectionAsync(this);
}
}
void TCPConnection::MaybeReconnect() {
RTC_DCHECK_RUN_ON(network_thread());
// Only reconnect for an outgoing TCPConnection when OnClose was signaled and
// no outstanding reconnect is pending.
if (connected() || connection_pending_ || !outgoing_) {
return;
}
RTC_LOG(LS_INFO) << ToString()
<< ": TCP Connection with remote is closed, "
"trying to reconnect";
CreateOutgoingTcpSocket();
error_ = EPIPE;
}
void TCPConnection::OnReadPacket(rtc::AsyncPacketSocket* socket,
const rtc::ReceivedPacket& packet) {
RTC_DCHECK_RUN_ON(network_thread());
RTC_DCHECK_EQ(socket, socket_.get());
Connection::OnReadPacket(packet);
}
void TCPConnection::OnReadyToSend(rtc::AsyncPacketSocket* socket) {
RTC_DCHECK_RUN_ON(network_thread());
RTC_DCHECK_EQ(socket, socket_.get());
Connection::OnReadyToSend();
}
void TCPConnection::OnDestroyed(Connection* c) {
RTC_DCHECK_RUN_ON(network_thread());
RTC_DCHECK_EQ(c, this);
if (socket_) {
DisconnectSocketSignals(socket_.get());
}
}
void TCPConnection::CreateOutgoingTcpSocket() {
RTC_DCHECK(outgoing_);
int opts = (remote_candidate().protocol() == SSLTCP_PROTOCOL_NAME)
? rtc::PacketSocketFactory::OPT_TLS_FAKE
: 0;
if (socket_) {
DisconnectSocketSignals(socket_.get());
}
rtc::PacketSocketTcpOptions tcp_opts;
tcp_opts.opts = opts;
socket_.reset(port()->socket_factory()->CreateClientTcpSocket(
rtc::SocketAddress(port()->Network()->GetBestIP(), 0),
remote_candidate().address(), tcp_opts));
if (socket_) {
RTC_LOG(LS_VERBOSE) << ToString() << ": Connecting from "
<< socket_->GetLocalAddress().ToSensitiveString()
<< " to "
<< remote_candidate().address().ToSensitiveString();
set_connected(false);
connection_pending_ = true;
ConnectSocketSignals(socket_.get());
} else {
RTC_LOG(LS_WARNING) << ToString() << ": Failed to create connection to "
<< remote_candidate().address().ToSensitiveString();
set_state(IceCandidatePairState::FAILED);
// We can't FailAndPrune directly here. FailAndPrune and deletes all
// the StunRequests from the request_map_. And if this is in the stack
// of Connection::Ping(), we are still using the request.
// Unwind the stack and defer the FailAndPrune.
network_thread()->PostTask(
SafeTask(network_safety_.flag(), [this]() { FailAndPrune(); }));
}
}
void TCPConnection::ConnectSocketSignals(rtc::AsyncPacketSocket* socket) {
// Incoming connections register SignalSentPacket and SignalReadyToSend
// directly on the port in TCPPort::OnNewConnection.
if (outgoing_) {
socket->SignalConnect.connect(this, &TCPConnection::OnConnect);
socket->SignalSentPacket.connect(this, &TCPConnection::OnSentPacket);
socket->SignalReadyToSend.connect(this, &TCPConnection::OnReadyToSend);
}
// For incoming connections, this re-register ReceivedPacketCallback to the
// connection instead of the port.
socket->RegisterReceivedPacketCallback(
[&](rtc::AsyncPacketSocket* socket, const rtc::ReceivedPacket& packet) {
OnReadPacket(socket, packet);
});
socket->SubscribeCloseEvent(this, [this, safety = network_safety_.flag()](
rtc::AsyncPacketSocket* s, int err) {
if (safety->alive())
OnClose(s, err);
});
}
void TCPConnection::DisconnectSocketSignals(rtc::AsyncPacketSocket* socket) {
if (outgoing_) {
// Incoming connections do not register these signals in TCPConnection.
socket->SignalConnect.disconnect(this);
socket->SignalReadyToSend.disconnect(this);
socket->SignalSentPacket.disconnect(this);
}
socket->DeregisterReceivedPacketCallback();
socket->UnsubscribeCloseEvent(this);
}
} // namespace cricket