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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 "p2p/base/stun_port.h"
#include <utility>
#include <vector>
#include "absl/memory/memory.h"
#include "absl/strings/string_view.h"
#include "api/transport/stun.h"
#include "p2p/base/connection.h"
#include "p2p/base/p2p_constants.h"
#include "p2p/base/port_allocator.h"
#include "rtc_base/checks.h"
#include "rtc_base/crypto_random.h"
#include "rtc_base/experiments/field_trial_parser.h"
#include "rtc_base/ip_address.h"
#include "rtc_base/logging.h"
#include "rtc_base/network/received_packet.h"
#include "rtc_base/strings/string_builder.h"
namespace cricket {
// TODO(?): Move these to a common place (used in relayport too)
const int RETRY_TIMEOUT = 50 * 1000; // 50 seconds
// Stop logging errors in UDPPort::SendTo after we have logged
// `kSendErrorLogLimit` messages. Start again after a successful send.
const int kSendErrorLogLimit = 5;
// Handles a binding request sent to the STUN server.
class StunBindingRequest : public StunRequest {
public:
StunBindingRequest(UDPPort* port,
const rtc::SocketAddress& addr,
int64_t start_time)
: StunRequest(port->request_manager(),
std::make_unique<StunMessage>(STUN_BINDING_REQUEST)),
port_(port),
server_addr_(addr),
start_time_(start_time) {
SetAuthenticationRequired(false);
}
const rtc::SocketAddress& server_addr() const { return server_addr_; }
void OnResponse(StunMessage* response) override {
const StunAddressAttribute* addr_attr =
response->GetAddress(STUN_ATTR_MAPPED_ADDRESS);
if (!addr_attr) {
RTC_LOG(LS_ERROR) << "Binding response missing mapped address.";
} else if (addr_attr->family() != STUN_ADDRESS_IPV4 &&
addr_attr->family() != STUN_ADDRESS_IPV6) {
RTC_LOG(LS_ERROR) << "Binding address has bad family";
} else {
rtc::SocketAddress addr(addr_attr->ipaddr(), addr_attr->port());
port_->OnStunBindingRequestSucceeded(this->Elapsed(), server_addr_, addr);
}
// The keep-alive requests will be stopped after its lifetime has passed.
if (WithinLifetime(rtc::TimeMillis())) {
port_->request_manager_.SendDelayed(
new StunBindingRequest(port_, server_addr_, start_time_),
port_->stun_keepalive_delay());
}
}
void OnErrorResponse(StunMessage* response) override {
const StunErrorCodeAttribute* attr = response->GetErrorCode();
if (!attr) {
RTC_LOG(LS_ERROR) << "Missing binding response error code.";
} else {
RTC_LOG(LS_ERROR) << "Binding error response:"
" class="
<< attr->eclass() << " number=" << attr->number()
<< " reason=" << attr->reason();
}
port_->OnStunBindingOrResolveRequestFailed(
server_addr_, attr ? attr->number() : STUN_ERROR_GLOBAL_FAILURE,
attr ? attr->reason()
: "STUN binding response with no error code attribute.");
int64_t now = rtc::TimeMillis();
if (WithinLifetime(now) &&
rtc::TimeDiff(now, start_time_) < RETRY_TIMEOUT) {
port_->request_manager_.SendDelayed(
new StunBindingRequest(port_, server_addr_, start_time_),
port_->stun_keepalive_delay());
}
}
void OnTimeout() override {
RTC_LOG(LS_ERROR) << "Binding request timed out from "
<< port_->GetLocalAddress().ToSensitiveString() << " ("
<< port_->Network()->name() << ")";
port_->OnStunBindingOrResolveRequestFailed(
server_addr_, STUN_ERROR_SERVER_NOT_REACHABLE,
"STUN binding request timed out.");
}
private:
// Returns true if `now` is within the lifetime of the request (a negative
// lifetime means infinite).
bool WithinLifetime(int64_t now) const {
int lifetime = port_->stun_keepalive_lifetime();
return lifetime < 0 || rtc::TimeDiff(now, start_time_) <= lifetime;
}
UDPPort* port_;
const rtc::SocketAddress server_addr_;
int64_t start_time_;
};
UDPPort::AddressResolver::AddressResolver(
rtc::PacketSocketFactory* factory,
std::function<void(const rtc::SocketAddress&, int)> done_callback)
: socket_factory_(factory), done_(std::move(done_callback)) {}
void UDPPort::AddressResolver::Resolve(
const rtc::SocketAddress& address,
int family,
const webrtc::FieldTrialsView& field_trials) {
if (resolvers_.find(address) != resolvers_.end())
return;
auto resolver = socket_factory_->CreateAsyncDnsResolver();
auto resolver_ptr = resolver.get();
std::pair<rtc::SocketAddress,
std::unique_ptr<webrtc::AsyncDnsResolverInterface>>
pair = std::make_pair(address, std::move(resolver));
resolvers_.insert(std::move(pair));
auto callback = [this, address] {
ResolverMap::const_iterator it = resolvers_.find(address);
if (it != resolvers_.end()) {
done_(it->first, it->second->result().GetError());
}
};
resolver_ptr->Start(address, family, std::move(callback));
}
bool UDPPort::AddressResolver::GetResolvedAddress(
const rtc::SocketAddress& input,
int family,
rtc::SocketAddress* output) const {
ResolverMap::const_iterator it = resolvers_.find(input);
if (it == resolvers_.end())
return false;
return it->second->result().GetResolvedAddress(family, output);
}
UDPPort::UDPPort(const PortParametersRef& args,
webrtc::IceCandidateType type,
rtc::AsyncPacketSocket* socket,
bool emit_local_for_anyaddress)
: Port(args, type),
request_manager_(
args.network_thread,
[this](const void* data, size_t size, StunRequest* request) {
OnSendPacket(data, size, request);
}),
socket_(socket),
error_(0),
ready_(false),
stun_keepalive_delay_(STUN_KEEPALIVE_INTERVAL),
dscp_(rtc::DSCP_NO_CHANGE),
emit_local_for_anyaddress_(emit_local_for_anyaddress) {}
UDPPort::UDPPort(const PortParametersRef& args,
webrtc::IceCandidateType type,
uint16_t min_port,
uint16_t max_port,
bool emit_local_for_anyaddress)
: Port(args, type, min_port, max_port),
request_manager_(
args.network_thread,
[this](const void* data, size_t size, StunRequest* request) {
OnSendPacket(data, size, request);
}),
socket_(nullptr),
error_(0),
ready_(false),
stun_keepalive_delay_(STUN_KEEPALIVE_INTERVAL),
dscp_(rtc::DSCP_NO_CHANGE),
emit_local_for_anyaddress_(emit_local_for_anyaddress) {}
bool UDPPort::Init() {
stun_keepalive_lifetime_ = GetStunKeepaliveLifetime();
if (!SharedSocket()) {
RTC_DCHECK(socket_ == nullptr);
socket_ = socket_factory()->CreateUdpSocket(
rtc::SocketAddress(Network()->GetBestIP(), 0), min_port(), max_port());
if (!socket_) {
RTC_LOG(LS_WARNING) << ToString() << ": UDP socket creation failed";
return false;
}
socket_->RegisterReceivedPacketCallback(
[&](rtc::AsyncPacketSocket* socket, const rtc::ReceivedPacket& packet) {
OnReadPacket(socket, packet);
});
}
socket_->SignalSentPacket.connect(this, &UDPPort::OnSentPacket);
socket_->SignalReadyToSend.connect(this, &UDPPort::OnReadyToSend);
socket_->SignalAddressReady.connect(this, &UDPPort::OnLocalAddressReady);
return true;
}
UDPPort::~UDPPort() {
if (!SharedSocket())
delete socket_;
}
void UDPPort::PrepareAddress() {
RTC_DCHECK(request_manager_.empty());
if (socket_->GetState() == rtc::AsyncPacketSocket::STATE_BOUND) {
OnLocalAddressReady(socket_, socket_->GetLocalAddress());
}
}
void UDPPort::MaybePrepareStunCandidate() {
// Sending binding request to the STUN server if address is available to
// prepare STUN candidate.
if (!server_addresses_.empty()) {
SendStunBindingRequests();
} else {
// Port is done allocating candidates.
MaybeSetPortCompleteOrError();
}
}
Connection* UDPPort::CreateConnection(const Candidate& address,
CandidateOrigin origin) {
if (!SupportsProtocol(address.protocol())) {
return nullptr;
}
if (!IsCompatibleAddress(address.address())) {
return nullptr;
}
// In addition to DCHECK-ing the non-emptiness of local candidates, we also
// skip this Port with null if there are latent bugs to violate it; otherwise
// it would lead to a crash when accessing the local candidate of the
// connection that would be created below.
if (Candidates().empty()) {
RTC_DCHECK_NOTREACHED();
return nullptr;
}
// When the socket is shared, the srflx candidate is gathered by the UDPPort.
// The assumption here is that
// 1) if the IP concealment with mDNS is not enabled, the gathering of the
// host candidate of this port (which is synchronous),
// 2) or otherwise if enabled, the start of name registration of the host
// candidate (as the start of asynchronous gathering)
// is always before the gathering of a srflx candidate (and any prflx
// candidate).
//
// See also the definition of MdnsNameRegistrationStatus::kNotStarted in
// port.h.
RTC_DCHECK(!SharedSocket() || Candidates()[0].is_local() ||
mdns_name_registration_status() !=
MdnsNameRegistrationStatus::kNotStarted);
Connection* conn = new ProxyConnection(NewWeakPtr(), 0, address);
AddOrReplaceConnection(conn);
return conn;
}
int UDPPort::SendTo(const void* data,
size_t size,
const rtc::SocketAddress& addr,
const rtc::PacketOptions& options,
bool payload) {
rtc::PacketOptions modified_options(options);
CopyPortInformationToPacketInfo(&modified_options.info_signaled_after_sent);
int sent = socket_->SendTo(data, size, addr, modified_options);
if (sent < 0) {
error_ = socket_->GetError();
// Rate limiting added for crbug.com/856088.
// TODO(webrtc:9622): Use general rate limiting mechanism once it exists.
if (send_error_count_ < kSendErrorLogLimit) {
++send_error_count_;
RTC_LOG(LS_ERROR) << ToString() << ": UDP send of " << size
<< " bytes to host "
<< addr.ToSensitiveNameAndAddressString()
<< " failed with error " << error_;
}
} else {
send_error_count_ = 0;
}
return sent;
}
void UDPPort::UpdateNetworkCost() {
Port::UpdateNetworkCost();
stun_keepalive_lifetime_ = GetStunKeepaliveLifetime();
}
rtc::DiffServCodePoint UDPPort::StunDscpValue() const {
return dscp_;
}
int UDPPort::SetOption(rtc::Socket::Option opt, int value) {
if (opt == rtc::Socket::OPT_DSCP) {
// Save value for future packets we instantiate.
dscp_ = static_cast<rtc::DiffServCodePoint>(value);
}
return socket_->SetOption(opt, value);
}
int UDPPort::GetOption(rtc::Socket::Option opt, int* value) {
return socket_->GetOption(opt, value);
}
int UDPPort::GetError() {
return error_;
}
bool UDPPort::HandleIncomingPacket(rtc::AsyncPacketSocket* socket,
const rtc::ReceivedPacket& packet) {
// All packets given to UDP port will be consumed.
OnReadPacket(socket, packet);
return true;
}
bool UDPPort::SupportsProtocol(absl::string_view protocol) const {
return protocol == UDP_PROTOCOL_NAME;
}
ProtocolType UDPPort::GetProtocol() const {
return PROTO_UDP;
}
void UDPPort::GetStunStats(std::optional<StunStats>* stats) {
*stats = stats_;
}
void UDPPort::set_stun_keepalive_delay(const std::optional<int>& delay) {
stun_keepalive_delay_ = delay.value_or(STUN_KEEPALIVE_INTERVAL);
}
void UDPPort::OnLocalAddressReady(rtc::AsyncPacketSocket* socket,
const rtc::SocketAddress& address) {
// When adapter enumeration is disabled and binding to the any address, the
// default local address will be issued as a candidate instead if
// `emit_local_for_anyaddress` is true. This is to allow connectivity for
// applications which absolutely requires a HOST candidate.
rtc::SocketAddress addr = address;
// If MaybeSetDefaultLocalAddress fails, we keep the "any" IP so that at
// least the port is listening.
MaybeSetDefaultLocalAddress(&addr);
AddAddress(addr, addr, rtc::SocketAddress(), UDP_PROTOCOL_NAME, "", "",
webrtc::IceCandidateType::kHost, ICE_TYPE_PREFERENCE_HOST, 0, "",
false);
MaybePrepareStunCandidate();
}
void UDPPort::PostAddAddress(bool is_final) {
MaybeSetPortCompleteOrError();
}
void UDPPort::OnReadPacket(rtc::AsyncPacketSocket* socket,
const rtc::ReceivedPacket& packet) {
RTC_DCHECK(socket == socket_);
RTC_DCHECK(!packet.source_address().IsUnresolvedIP());
// Look for a response from the STUN server.
// Even if the response doesn't match one of our outstanding requests, we
// will eat it because it might be a response to a retransmitted packet, and
// we already cleared the request when we got the first response.
if (server_addresses_.find(packet.source_address()) !=
server_addresses_.end()) {
request_manager_.CheckResponse(
reinterpret_cast<const char*>(packet.payload().data()),
packet.payload().size());
return;
}
if (Connection* conn = GetConnection(packet.source_address())) {
conn->OnReadPacket(packet);
} else {
Port::OnReadPacket(packet, PROTO_UDP);
}
}
void UDPPort::OnSentPacket(rtc::AsyncPacketSocket* socket,
const rtc::SentPacket& sent_packet) {
PortInterface::SignalSentPacket(sent_packet);
}
void UDPPort::OnReadyToSend(rtc::AsyncPacketSocket* socket) {
Port::OnReadyToSend();
}
void UDPPort::SendStunBindingRequests() {
// We will keep pinging the stun server to make sure our NAT pin-hole stays
// open until the deadline (specified in SendStunBindingRequest).
RTC_DCHECK(request_manager_.empty());
for (ServerAddresses::const_iterator it = server_addresses_.begin();
it != server_addresses_.end();) {
// sending a STUN binding request may cause the current SocketAddress to be
// erased from the set, invalidating the loop iterator before it is
// incremented (even if the SocketAddress itself still exists). So make a
// copy of the loop iterator, which may be safely invalidated.
ServerAddresses::const_iterator addr = it++;
SendStunBindingRequest(*addr);
}
}
void UDPPort::ResolveStunAddress(const rtc::SocketAddress& stun_addr) {
if (!resolver_) {
resolver_.reset(new AddressResolver(
socket_factory(), [&](const rtc::SocketAddress& input, int error) {
OnResolveResult(input, error);
}));
}
RTC_LOG(LS_INFO) << ToString() << ": Starting STUN host lookup for "
<< stun_addr.ToSensitiveString();
resolver_->Resolve(stun_addr, Network()->family(), field_trials());
}
void UDPPort::OnResolveResult(const rtc::SocketAddress& input, int error) {
RTC_DCHECK(resolver_.get() != nullptr);
rtc::SocketAddress resolved;
if (error != 0 || !resolver_->GetResolvedAddress(
input, Network()->GetBestIP().family(), &resolved)) {
RTC_LOG(LS_WARNING) << ToString()
<< ": StunPort: stun host lookup received error "
<< error;
OnStunBindingOrResolveRequestFailed(input, STUN_ERROR_SERVER_NOT_REACHABLE,
"STUN host lookup received error.");
return;
}
server_addresses_.erase(input);
if (server_addresses_.find(resolved) == server_addresses_.end()) {
server_addresses_.insert(resolved);
SendStunBindingRequest(resolved);
}
}
void UDPPort::SendStunBindingRequest(const rtc::SocketAddress& stun_addr) {
if (stun_addr.IsUnresolvedIP()) {
ResolveStunAddress(stun_addr);
} else if (socket_->GetState() == rtc::AsyncPacketSocket::STATE_BOUND) {
// Check if `server_addr_` is compatible with the port's ip.
if (IsCompatibleAddress(stun_addr)) {
request_manager_.Send(
new StunBindingRequest(this, stun_addr, rtc::TimeMillis()));
} else {
// Since we can't send stun messages to the server, we should mark this
// port ready. This is not an error but similar to ignoring
// a mismatch of th address family when pairing candidates.
RTC_LOG(LS_WARNING) << ToString()
<< ": STUN server address is incompatible.";
OnStunBindingOrResolveRequestFailed(
stun_addr, STUN_ERROR_NOT_AN_ERROR,
"STUN server address is incompatible.");
}
}
}
bool UDPPort::MaybeSetDefaultLocalAddress(rtc::SocketAddress* addr) const {
if (!addr->IsAnyIP() || !emit_local_for_anyaddress_ ||
!Network()->default_local_address_provider()) {
return true;
}
rtc::IPAddress default_address;
bool result =
Network()->default_local_address_provider()->GetDefaultLocalAddress(
addr->family(), &default_address);
if (!result || default_address.IsNil()) {
return false;
}
addr->SetIP(default_address);
return true;
}
void UDPPort::OnStunBindingRequestSucceeded(
int rtt_ms,
const rtc::SocketAddress& stun_server_addr,
const rtc::SocketAddress& stun_reflected_addr) {
RTC_DCHECK(stats_.stun_binding_responses_received <
stats_.stun_binding_requests_sent);
stats_.stun_binding_responses_received++;
stats_.stun_binding_rtt_ms_total += rtt_ms;
stats_.stun_binding_rtt_ms_squared_total += rtt_ms * rtt_ms;
if (bind_request_succeeded_servers_.find(stun_server_addr) !=
bind_request_succeeded_servers_.end()) {
return;
}
bind_request_succeeded_servers_.insert(stun_server_addr);
// If socket is shared and `stun_reflected_addr` is equal to local socket
// address and mDNS obfuscation is not enabled, or if the same address has
// been added by another STUN server, then discarding the stun address.
// For STUN, related address is the local socket address.
if ((!SharedSocket() || stun_reflected_addr != socket_->GetLocalAddress() ||
Network()->GetMdnsResponder() != nullptr) &&
!HasStunCandidateWithAddress(stun_reflected_addr)) {
rtc::SocketAddress related_address = socket_->GetLocalAddress();
// If we can't stamp the related address correctly, empty it to avoid leak.
if (!MaybeSetDefaultLocalAddress(&related_address)) {
related_address =
rtc::EmptySocketAddressWithFamily(related_address.family());
}
rtc::StringBuilder url;
url << "stun:" << stun_server_addr.hostname() << ":"
<< stun_server_addr.port();
AddAddress(stun_reflected_addr, socket_->GetLocalAddress(), related_address,
UDP_PROTOCOL_NAME, "", "", webrtc::IceCandidateType::kSrflx,
ICE_TYPE_PREFERENCE_SRFLX, 0, url.str(), false);
}
MaybeSetPortCompleteOrError();
}
void UDPPort::OnStunBindingOrResolveRequestFailed(
const rtc::SocketAddress& stun_server_addr,
int error_code,
absl::string_view reason) {
if (error_code != STUN_ERROR_NOT_AN_ERROR) {
rtc::StringBuilder url;
url << "stun:" << stun_server_addr.ToString();
SignalCandidateError(
this, IceCandidateErrorEvent(
GetLocalAddress().HostAsSensitiveURIString(),
GetLocalAddress().port(), url.str(), error_code, reason));
}
if (bind_request_failed_servers_.find(stun_server_addr) !=
bind_request_failed_servers_.end()) {
return;
}
bind_request_failed_servers_.insert(stun_server_addr);
MaybeSetPortCompleteOrError();
}
void UDPPort::MaybeSetPortCompleteOrError() {
if (mdns_name_registration_status() ==
MdnsNameRegistrationStatus::kInProgress) {
return;
}
if (ready_) {
return;
}
// Do not set port ready if we are still waiting for bind responses.
const size_t servers_done_bind_request =
bind_request_failed_servers_.size() +
bind_request_succeeded_servers_.size();
if (server_addresses_.size() != servers_done_bind_request) {
return;
}
// Setting ready status.
ready_ = true;
// The port is "completed" if there is no stun server provided, or the bind
// request succeeded for any stun server, or the socket is shared.
if (server_addresses_.empty() || bind_request_succeeded_servers_.size() > 0 ||
SharedSocket()) {
SignalPortComplete(this);
} else {
SignalPortError(this);
}
}
// TODO(?): merge this with SendTo above.
void UDPPort::OnSendPacket(const void* data, size_t size, StunRequest* req) {
StunBindingRequest* sreq = static_cast<StunBindingRequest*>(req);
rtc::PacketOptions options(StunDscpValue());
options.info_signaled_after_sent.packet_type = rtc::PacketType::kStunMessage;
CopyPortInformationToPacketInfo(&options.info_signaled_after_sent);
if (socket_->SendTo(data, size, sreq->server_addr(), options) < 0) {
RTC_LOG_ERR_EX(LS_ERROR, socket_->GetError())
<< "UDP send of " << size << " bytes to host "
<< sreq->server_addr().ToSensitiveNameAndAddressString()
<< " failed with error " << error_;
}
stats_.stun_binding_requests_sent++;
}
bool UDPPort::HasStunCandidateWithAddress(
const rtc::SocketAddress& addr) const {
const std::vector<Candidate>& existing_candidates = Candidates();
std::vector<Candidate>::const_iterator it = existing_candidates.begin();
for (; it != existing_candidates.end(); ++it) {
if (it->is_stun() && it->address() == addr)
return true;
}
return false;
}
std::unique_ptr<StunPort> StunPort::Create(
const PortParametersRef& args,
uint16_t min_port,
uint16_t max_port,
const ServerAddresses& servers,
std::optional<int> stun_keepalive_interval) {
// Using `new` to access a non-public constructor.
auto port = absl::WrapUnique(new StunPort(args, min_port, max_port, servers));
port->set_stun_keepalive_delay(stun_keepalive_interval);
if (!port->Init()) {
return nullptr;
}
return port;
}
std::unique_ptr<StunPort> StunPort::Create(
webrtc::TaskQueueBase* thread,
rtc::PacketSocketFactory* factory,
const rtc::Network* network,
uint16_t min_port,
uint16_t max_port,
absl::string_view username,
absl::string_view password,
const ServerAddresses& servers,
std::optional<int> stun_keepalive_interval,
const webrtc::FieldTrialsView* field_trials) {
return Create({.network_thread = thread,
.socket_factory = factory,
.network = network,
.ice_username_fragment = username,
.ice_password = password,
.field_trials = field_trials},
min_port, max_port, servers, stun_keepalive_interval);
}
StunPort::StunPort(const PortParametersRef& args,
uint16_t min_port,
uint16_t max_port,
const ServerAddresses& servers)
: UDPPort(args,
webrtc::IceCandidateType::kSrflx,
min_port,
max_port,
false) {
set_server_addresses(servers);
}
void StunPort::PrepareAddress() {
SendStunBindingRequests();
}
} // namespace cricket