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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 "pc/jseptransport.h"
#include <memory>
#include <utility> // for std::pair
#include "api/candidate.h"
#include "p2p/base/p2pconstants.h"
#include "p2p/base/p2ptransportchannel.h"
#include "p2p/base/port.h"
#include "rtc_base/bind.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
using webrtc::SdpType;
namespace cricket {
TransportChannelStats::TransportChannelStats() = default;
TransportChannelStats::TransportChannelStats(const TransportChannelStats&) =
default;
TransportChannelStats::~TransportChannelStats() = default;
TransportStats::TransportStats() = default;
TransportStats::~TransportStats() = default;
bool BadTransportDescription(const std::string& desc, std::string* err_desc) {
if (err_desc) {
*err_desc = desc;
}
RTC_LOG(LS_ERROR) << desc;
return false;
}
static bool VerifyIceParams(const TransportDescription& desc) {
// For legacy protocols.
if (desc.ice_ufrag.empty() && desc.ice_pwd.empty())
return true;
if (desc.ice_ufrag.length() < ICE_UFRAG_MIN_LENGTH ||
desc.ice_ufrag.length() > ICE_UFRAG_MAX_LENGTH) {
return false;
}
if (desc.ice_pwd.length() < ICE_PWD_MIN_LENGTH ||
desc.ice_pwd.length() > ICE_PWD_MAX_LENGTH) {
return false;
}
return true;
}
JsepTransport::JsepTransport(
const std::string& mid,
const rtc::scoped_refptr<rtc::RTCCertificate>& certificate)
: mid_(mid), certificate_(certificate) {}
JsepTransport::~JsepTransport() = default;
bool JsepTransport::AddChannel(DtlsTransportInternal* dtls, int component) {
if (channels_.find(component) != channels_.end()) {
RTC_LOG(LS_ERROR) << "Adding channel for component " << component
<< " twice.";
return false;
}
channels_[component] = dtls;
// Something's wrong if a channel is being added after a description is set.
// This may currently occur if rtcp-mux is negotiated, then a new m= section
// is added in a later offer/answer. But this is suboptimal and should be
// changed; we shouldn't support going from muxed to non-muxed.
// TODO(deadbeef): Once this is fixed, make the warning an error, and remove
// the calls to "ApplyXTransportDescription" below.
if (local_description_set_ || remote_description_set_) {
RTC_LOG(LS_WARNING) << "Adding new transport channel after "
"transport description already applied.";
}
bool ret = true;
std::string err;
if (local_description_set_) {
ret &= ApplyLocalTransportDescription(channels_[component], &err);
}
if (remote_description_set_) {
ret &= ApplyRemoteTransportDescription(channels_[component], &err);
}
if (local_description_set_ && remote_description_set_) {
ret &= ApplyNegotiatedTransportDescription(channels_[component], &err);
}
return ret;
}
bool JsepTransport::RemoveChannel(int component) {
auto it = channels_.find(component);
if (it == channels_.end()) {
RTC_LOG(LS_ERROR) << "Trying to remove channel for component " << component
<< ", which doesn't exist.";
return false;
}
channels_.erase(component);
return true;
}
bool JsepTransport::HasChannels() const {
return !channels_.empty();
}
void JsepTransport::SetLocalCertificate(
const rtc::scoped_refptr<rtc::RTCCertificate>& certificate) {
certificate_ = certificate;
}
bool JsepTransport::GetLocalCertificate(
rtc::scoped_refptr<rtc::RTCCertificate>* certificate) const {
if (!certificate_) {
return false;
}
*certificate = certificate_;
return true;
}
bool JsepTransport::SetLocalTransportDescription(
const TransportDescription& description,
SdpType type,
std::string* error_desc) {
bool ret = true;
if (!VerifyIceParams(description)) {
return BadTransportDescription("Invalid ice-ufrag or ice-pwd length",
error_desc);
}
bool ice_restarting =
local_description_set_ &&
IceCredentialsChanged(local_description_->ice_ufrag,
local_description_->ice_pwd, description.ice_ufrag,
description.ice_pwd);
local_description_.reset(new TransportDescription(description));
rtc::SSLFingerprint* local_fp =
local_description_->identity_fingerprint.get();
if (!local_fp) {
certificate_ = nullptr;
} else if (!VerifyCertificateFingerprint(certificate_.get(), local_fp,
error_desc)) {
return false;
}
for (const auto& kv : channels_) {
ret &= ApplyLocalTransportDescription(kv.second, error_desc);
}
if (!ret) {
return false;
}
// If PRANSWER/ANSWER is set, we should decide transport protocol type.
if (type == SdpType::kPrAnswer || type == SdpType::kAnswer) {
ret &= NegotiateTransportDescription(type, error_desc);
}
if (!ret) {
return false;
}
if (needs_ice_restart_ && ice_restarting) {
needs_ice_restart_ = false;
RTC_LOG(LS_VERBOSE) << "needs-ice-restart flag cleared for transport "
<< mid();
}
local_description_set_ = true;
return true;
}
bool JsepTransport::SetRemoteTransportDescription(
const TransportDescription& description,
SdpType type,
std::string* error_desc) {
bool ret = true;
if (!VerifyIceParams(description)) {
return BadTransportDescription("Invalid ice-ufrag or ice-pwd length",
error_desc);
}
remote_description_.reset(new TransportDescription(description));
for (const auto& kv : channels_) {
ret &= ApplyRemoteTransportDescription(kv.second, error_desc);
}
// If PRANSWER/ANSWER is set, we should decide transport protocol type.
if (type == SdpType::kPrAnswer || type == SdpType::kAnswer) {
ret = NegotiateTransportDescription(SdpType::kOffer, error_desc);
}
if (ret) {
remote_description_set_ = true;
}
return ret;
}
void JsepTransport::SetNeedsIceRestartFlag() {
if (!needs_ice_restart_) {
needs_ice_restart_ = true;
RTC_LOG(LS_VERBOSE) << "needs-ice-restart flag set for transport " << mid();
}
}
bool JsepTransport::NeedsIceRestart() const {
return needs_ice_restart_;
}
rtc::Optional<rtc::SSLRole> JsepTransport::GetSslRole() const {
return ssl_role_;
}
bool JsepTransport::GetStats(TransportStats* stats) {
stats->transport_name = mid();
stats->channel_stats.clear();
for (auto& kv : channels_) {
DtlsTransportInternal* dtls_transport = kv.second;
TransportChannelStats substats;
substats.component = kv.first;
dtls_transport->GetSrtpCryptoSuite(&substats.srtp_crypto_suite);
dtls_transport->GetSslCipherSuite(&substats.ssl_cipher_suite);
substats.dtls_state = dtls_transport->dtls_state();
if (!dtls_transport->ice_transport()->GetStats(
&substats.connection_infos)) {
return false;
}
stats->channel_stats.push_back(substats);
}
return true;
}
bool JsepTransport::VerifyCertificateFingerprint(
const rtc::RTCCertificate* certificate,
const rtc::SSLFingerprint* fingerprint,
std::string* error_desc) const {
if (!fingerprint) {
return BadTransportDescription("No fingerprint.", error_desc);
}
if (!certificate) {
return BadTransportDescription(
"Fingerprint provided but no identity available.", error_desc);
}
std::unique_ptr<rtc::SSLFingerprint> fp_tmp(rtc::SSLFingerprint::Create(
fingerprint->algorithm, certificate->identity()));
RTC_DCHECK(fp_tmp.get() != NULL);
if (*fp_tmp == *fingerprint) {
return true;
}
std::ostringstream desc;
desc << "Local fingerprint does not match identity. Expected: ";
desc << fp_tmp->ToString();
desc << " Got: " << fingerprint->ToString();
return BadTransportDescription(desc.str(), error_desc);
}
bool JsepTransport::ApplyLocalTransportDescription(
DtlsTransportInternal* dtls_transport,
std::string* error_desc) {
dtls_transport->ice_transport()->SetIceParameters(
local_description_->GetIceParameters());
return true;
}
bool JsepTransport::ApplyRemoteTransportDescription(
DtlsTransportInternal* dtls_transport,
std::string* error_desc) {
dtls_transport->ice_transport()->SetRemoteIceParameters(
remote_description_->GetIceParameters());
dtls_transport->ice_transport()->SetRemoteIceMode(
remote_description_->ice_mode);
return true;
}
bool JsepTransport::ApplyNegotiatedTransportDescription(
DtlsTransportInternal* dtls_transport,
std::string* error_desc) {
// Set SSL role. Role must be set before fingerprint is applied, which
// initiates DTLS setup.
if (ssl_role_ && !dtls_transport->SetSslRole(*ssl_role_)) {
return BadTransportDescription("Failed to set SSL role for the channel.",
error_desc);
}
// Apply remote fingerprint.
if (!dtls_transport->SetRemoteFingerprint(
remote_fingerprint_->algorithm,
reinterpret_cast<const uint8_t*>(remote_fingerprint_->digest.data()),
remote_fingerprint_->digest.size())) {
return BadTransportDescription("Failed to apply remote fingerprint.",
error_desc);
}
return true;
}
bool JsepTransport::NegotiateTransportDescription(
SdpType local_description_type,
std::string* error_desc) {
if (!local_description_ || !remote_description_) {
const std::string msg =
"Applying an answer transport description "
"without applying any offer.";
return BadTransportDescription(msg, error_desc);
}
rtc::SSLFingerprint* local_fp =
local_description_->identity_fingerprint.get();
rtc::SSLFingerprint* remote_fp =
remote_description_->identity_fingerprint.get();
if (remote_fp && local_fp) {
remote_fingerprint_.reset(new rtc::SSLFingerprint(*remote_fp));
if (!NegotiateRole(local_description_type, error_desc)) {
return false;
}
} else if (local_fp && (local_description_type == SdpType::kAnswer)) {
return BadTransportDescription(
"Local fingerprint supplied when caller didn't offer DTLS.",
error_desc);
} else {
// We are not doing DTLS
remote_fingerprint_.reset(new rtc::SSLFingerprint("", nullptr, 0));
}
// Now that we have negotiated everything, push it downward.
// Note that we cache the result so that if we have race conditions
// between future SetRemote/SetLocal invocations and new channel
// creation, we have the negotiation state saved until a new
// negotiation happens.
for (const auto& kv : channels_) {
if (!ApplyNegotiatedTransportDescription(kv.second, error_desc)) {
return false;
}
}
return true;
}
bool JsepTransport::NegotiateRole(SdpType local_description_type,
std::string* error_desc) {
if (!local_description_ || !remote_description_) {
const std::string msg =
"Local and Remote description must be set before "
"transport descriptions are negotiated";
return BadTransportDescription(msg, error_desc);
}
// From RFC 4145, section-4.1, The following are the values that the
// 'setup' attribute can take in an offer/answer exchange:
// Offer Answer
// ________________
// active passive / holdconn
// passive active / holdconn
// actpass active / passive / holdconn
// holdconn holdconn
//
// Set the role that is most conformant with RFC 5763, Section 5, bullet 1
// The endpoint MUST use the setup attribute defined in [RFC4145].
// The endpoint that is the offerer MUST use the setup attribute
// value of setup:actpass and be prepared to receive a client_hello
// before it receives the answer. The answerer MUST use either a
// setup attribute value of setup:active or setup:passive. Note that
// if the answerer uses setup:passive, then the DTLS handshake will
// not begin until the answerer is received, which adds additional
// latency. setup:active allows the answer and the DTLS handshake to
// occur in parallel. Thus, setup:active is RECOMMENDED. Whichever
// party is active MUST initiate a DTLS handshake by sending a
// ClientHello over each flow (host/port quartet).
// IOW - actpass and passive modes should be treated as server and
// active as client.
ConnectionRole local_connection_role = local_description_->connection_role;
ConnectionRole remote_connection_role = remote_description_->connection_role;
bool is_remote_server = false;
if (local_description_type == SdpType::kOffer) {
if (local_connection_role != CONNECTIONROLE_ACTPASS) {
return BadTransportDescription(
"Offerer must use actpass value for setup attribute.", error_desc);
}
if (remote_connection_role == CONNECTIONROLE_ACTIVE ||
remote_connection_role == CONNECTIONROLE_PASSIVE ||
remote_connection_role == CONNECTIONROLE_NONE) {
is_remote_server = (remote_connection_role == CONNECTIONROLE_PASSIVE);
} else {
const std::string msg =
"Answerer must use either active or passive value "
"for setup attribute.";
return BadTransportDescription(msg, error_desc);
}
// If remote is NONE or ACTIVE it will act as client.
} else {
if (remote_connection_role != CONNECTIONROLE_ACTPASS &&
remote_connection_role != CONNECTIONROLE_NONE) {
// Accept a remote role attribute that's not "actpass", but matches the
// current negotiated role. This is allowed by dtls-sdp, though our
// implementation will never generate such an offer as it's not
// recommended.
//
// See https://datatracker.ietf.org/doc/html/draft-ietf-mmusic-dtls-sdp,
// section 5.5.
if (!ssl_role_ ||
(*ssl_role_ == rtc::SSL_CLIENT &&
remote_connection_role == CONNECTIONROLE_ACTIVE) ||
(*ssl_role_ == rtc::SSL_SERVER &&
remote_connection_role == CONNECTIONROLE_PASSIVE)) {
return BadTransportDescription(
"Offerer must use actpass value or current negotiated role for "
"setup attribute.",
error_desc);
}
}
if (local_connection_role == CONNECTIONROLE_ACTIVE ||
local_connection_role == CONNECTIONROLE_PASSIVE) {
is_remote_server = (local_connection_role == CONNECTIONROLE_ACTIVE);
} else {
const std::string msg =
"Answerer must use either active or passive value "
"for setup attribute.";
return BadTransportDescription(msg, error_desc);
}
// If local is passive, local will act as server.
}
ssl_role_.emplace(is_remote_server ? rtc::SSL_CLIENT : rtc::SSL_SERVER);
return true;
}
} // namespace cricket