third_party/libwebrtc/pc/jsep_session_description.cc

   1 /*
   2  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11 #include "api/jsep_session_description.h"
  12
  13 #include <memory>
  14 #include <utility>
  15
  16 #include "absl/types/optional.h"
  17 #include "p2p/base/p2p_constants.h"
  18 #include "p2p/base/port.h"
  19 #include "p2p/base/transport_description.h"
  20 #include "p2p/base/transport_info.h"
  21 #include "pc/media_session.h"  // IWYU pragma: keep
  22 #include "pc/webrtc_sdp.h"
  23 #include "rtc_base/checks.h"
  24 #include "rtc_base/ip_address.h"
  25 #include "rtc_base/logging.h"
  26 #include "rtc_base/net_helper.h"
  27 #include "rtc_base/socket_address.h"
  28
  29 using cricket::Candidate;
  30 using cricket::SessionDescription;
  31
  32 namespace webrtc {
  33 namespace {
  34
  35 constexpr char kDummyAddress[] = "0.0.0.0";
  36 constexpr int kDummyPort = 9;
  37
  38 // Update the connection address for the MediaContentDescription based on the
  39 // candidates.
  40 void UpdateConnectionAddress(
  41     const JsepCandidateCollection& candidate_collection,
  42     cricket::MediaContentDescription* media_desc) {
  43   int port = kDummyPort;
  44   std::string ip = kDummyAddress;
  45   std::string hostname;
  46   int current_preference = 0;  // Start with lowest preference.
  47   int current_family = AF_UNSPEC;
  48   for (size_t i = 0; i < candidate_collection.count(); ++i) {
  49     const IceCandidateInterface* jsep_candidate = candidate_collection.at(i);
  50     if (jsep_candidate->candidate().component() !=
  51         cricket::ICE_CANDIDATE_COMPONENT_RTP) {
  52       continue;
  53     }
  54     // Default destination should be UDP only.
  55     if (jsep_candidate->candidate().protocol() != cricket::UDP_PROTOCOL_NAME) {
  56       continue;
  57     }
  58     const int preference = jsep_candidate->candidate().type_preference();
  59     const int family = jsep_candidate->candidate().address().ipaddr().family();
  60     // See if this candidate is more preferable then the current one if it's the
  61     // same family. Or if the current family is IPv4 already so we could safely
  62     // ignore all IPv6 ones. WebRTC bug 4269.
  63     // http://code.google.com/p/webrtc/issues/detail?id=4269
  64     if ((preference <= current_preference && current_family == family) ||
  65         (current_family == AF_INET && family == AF_INET6)) {
  66       continue;
  67     }
  68     current_preference = preference;
  69     current_family = family;
  70     const rtc::SocketAddress& candidate_addr =
  71         jsep_candidate->candidate().address();
  72     port = candidate_addr.port();
  73     ip = candidate_addr.ipaddr().ToString();
  74     hostname = candidate_addr.hostname();
  75   }
  76   rtc::SocketAddress connection_addr(ip, port);
  77   if (rtc::IPIsUnspec(connection_addr.ipaddr()) && !hostname.empty()) {
  78     // When a hostname candidate becomes the (default) connection address,
  79     // we use the dummy address 0.0.0.0 and port 9 in the c= and the m= lines.
  80     //
  81     // We have observed in deployment that with a FQDN in a c= line, SDP parsing
  82     // could fail in other JSEP implementations. We note that the wildcard
  83     // addresses (0.0.0.0 or ::) with port 9 are given the exception as the
  84     // connection address that will not result in an ICE mismatch
  85     // (draft-ietf-mmusic-ice-sip-sdp). Also, 0.0.0.0 or :: can be used as the
  86     // connection address in the initial offer or answer with trickle ICE
  87     // if the offerer or answerer does not want to include the host IP address
  88     // (draft-ietf-mmusic-trickle-ice-sip), and in particular 0.0.0.0 has been
  89     // widely deployed for this use without outstanding compatibility issues.
  90     // Combining the above considerations, we use 0.0.0.0 with port 9 to
  91     // populate the c= and the m= lines. See `BuildMediaDescription` in
  92     // webrtc_sdp.cc for the SDP generation with
  93     // `media_desc->connection_address()`.
  94     connection_addr = rtc::SocketAddress(kDummyAddress, kDummyPort);
  95   }
  96   media_desc->set_connection_address(connection_addr);
  97 }
  98
  99 }  // namespace
 100
 101 // TODO(steveanton): Remove this default implementation once Chromium has been
 102 // updated.
 103 SdpType SessionDescriptionInterface::GetType() const {
 104   absl::optional<SdpType> maybe_type = SdpTypeFromString(type());
 105   if (maybe_type) {
 106     return *maybe_type;
 107   } else {
 108     RTC_LOG(LS_WARNING) << "Default implementation of "
 109                            "SessionDescriptionInterface::GetType does not "
 110                            "recognize the result from type(), returning "
 111                            "kOffer.";
 112     return SdpType::kOffer;
 113   }
 114 }
 115
 116 SessionDescriptionInterface* CreateSessionDescription(const std::string& type,
 117                                                       const std::string& sdp,
 118                                                       SdpParseError* error) {
 119   absl::optional<SdpType> maybe_type = SdpTypeFromString(type);
 120   if (!maybe_type) {
 121     return nullptr;
 122   }
 123
 124   return CreateSessionDescription(*maybe_type, sdp, error).release();
 125 }
 126
 127 std::unique_ptr<SessionDescriptionInterface> CreateSessionDescription(
 128     SdpType type,
 129     const std::string& sdp) {
 130   return CreateSessionDescription(type, sdp, nullptr);
 131 }
 132
 133 std::unique_ptr<SessionDescriptionInterface> CreateSessionDescription(
 134     SdpType type,
 135     const std::string& sdp,
 136     SdpParseError* error_out) {
 137   auto jsep_desc = std::make_unique<JsepSessionDescription>(type);
 138   if (type != SdpType::kRollback) {
 139     if (!SdpDeserialize(sdp, jsep_desc.get(), error_out)) {
 140       return nullptr;
 141     }
 142   }
 143   return std::move(jsep_desc);
 144 }
 145
 146 std::unique_ptr<SessionDescriptionInterface> CreateSessionDescription(
 147     SdpType type,
 148     const std::string& session_id,
 149     const std::string& session_version,
 150     std::unique_ptr<cricket::SessionDescription> description) {
 151   auto jsep_description = std::make_unique<JsepSessionDescription>(type);
 152   bool initialize_success = jsep_description->Initialize(
 153       std::move(description), session_id, session_version);
 154   RTC_DCHECK(initialize_success);
 155   return std::move(jsep_description);
 156 }
 157
 158 JsepSessionDescription::JsepSessionDescription(SdpType type) : type_(type) {}
 159
 160 JsepSessionDescription::JsepSessionDescription(const std::string& type) {
 161   absl::optional<SdpType> maybe_type = SdpTypeFromString(type);
 162   if (maybe_type) {
 163     type_ = *maybe_type;
 164   } else {
 165     RTC_LOG(LS_WARNING)
 166         << "JsepSessionDescription constructed with invalid type string: "
 167         << type << ". Assuming it is an offer.";
 168     type_ = SdpType::kOffer;
 169   }
 170 }
 171
 172 JsepSessionDescription::JsepSessionDescription(
 173     SdpType type,
 174     std::unique_ptr<cricket::SessionDescription> description,
 175     absl::string_view session_id,
 176     absl::string_view session_version)
 177     : description_(std::move(description)),
 178       session_id_(session_id),
 179       session_version_(session_version),
 180       type_(type) {
 181   RTC_DCHECK(description_);
 182   candidate_collection_.resize(number_of_mediasections());
 183 }
 184
 185 JsepSessionDescription::~JsepSessionDescription() {}
 186
 187 bool JsepSessionDescription::Initialize(
 188     std::unique_ptr<cricket::SessionDescription> description,
 189     const std::string& session_id,
 190     const std::string& session_version) {
 191   if (!description)
 192     return false;
 193
 194   session_id_ = session_id;
 195   session_version_ = session_version;
 196   description_ = std::move(description);
 197   candidate_collection_.resize(number_of_mediasections());
 198   return true;
 199 }
 200
 201 std::unique_ptr<SessionDescriptionInterface> JsepSessionDescription::Clone()
 202     const {
 203   auto new_description = std::make_unique<JsepSessionDescription>(type_);
 204   new_description->session_id_ = session_id_;
 205   new_description->session_version_ = session_version_;
 206   if (description_) {
 207     new_description->description_ = description_->Clone();
 208   }
 209   for (const auto& collection : candidate_collection_) {
 210     new_description->candidate_collection_.push_back(collection.Clone());
 211   }
 212   return new_description;
 213 }
 214
 215 bool JsepSessionDescription::AddCandidate(
 216     const IceCandidateInterface* candidate) {
 217   if (!candidate)
 218     return false;
 219   size_t mediasection_index = 0;
 220   if (!GetMediasectionIndex(candidate, &mediasection_index)) {
 221     return false;
 222   }
 223   if (mediasection_index >= number_of_mediasections())
 224     return false;
 225   const std::string& content_name =
 226       description_->contents()[mediasection_index].name;
 227   const cricket::TransportInfo* transport_info =
 228       description_->GetTransportInfoByName(content_name);
 229   if (!transport_info) {
 230     return false;
 231   }
 232
 233   Candidate updated_candidate = candidate->candidate();
 234   if (updated_candidate.username().empty()) {
 235     updated_candidate.set_username(transport_info->description.ice_ufrag);
 236   }
 237   if (updated_candidate.password().empty()) {
 238     updated_candidate.set_password(transport_info->description.ice_pwd);
 239   }
 240
 241   std::unique_ptr<JsepIceCandidate> updated_candidate_wrapper(
 242       new JsepIceCandidate(candidate->sdp_mid(),
 243                            static_cast<int>(mediasection_index),
 244                            updated_candidate));
 245   if (!candidate_collection_[mediasection_index].HasCandidate(
 246           updated_candidate_wrapper.get())) {
 247     candidate_collection_[mediasection_index].add(
 248         updated_candidate_wrapper.release());
 249     UpdateConnectionAddress(
 250         candidate_collection_[mediasection_index],
 251         description_->contents()[mediasection_index].media_description());
 252   }
 253
 254   return true;
 255 }
 256
 257 size_t JsepSessionDescription::RemoveCandidates(
 258     const std::vector<Candidate>& candidates) {
 259   size_t num_removed = 0;
 260   for (auto& candidate : candidates) {
 261     int mediasection_index = GetMediasectionIndex(candidate);
 262     if (mediasection_index < 0) {
 263       // Not found.
 264       continue;
 265     }
 266     num_removed += candidate_collection_[mediasection_index].remove(candidate);
 267     UpdateConnectionAddress(
 268         candidate_collection_[mediasection_index],
 269         description_->contents()[mediasection_index].media_description());
 270   }
 271   return num_removed;
 272 }
 273
 274 size_t JsepSessionDescription::number_of_mediasections() const {
 275   if (!description_)
 276     return 0;
 277   return description_->contents().size();
 278 }
 279
 280 const IceCandidateCollection* JsepSessionDescription::candidates(
 281     size_t mediasection_index) const {
 282   if (mediasection_index >= candidate_collection_.size())
 283     return NULL;
 284   return &candidate_collection_[mediasection_index];
 285 }
 286
 287 bool JsepSessionDescription::ToString(std::string* out) const {
 288   if (!description_ || !out) {
 289     return false;
 290   }
 291   *out = SdpSerialize(*this);
 292   return !out->empty();
 293 }
 294
 295 bool JsepSessionDescription::GetMediasectionIndex(
 296     const IceCandidateInterface* candidate,
 297     size_t* index) {
 298   if (!candidate || !index) {
 299     return false;
 300   }
 301
 302   // If the candidate has no valid mline index or sdp_mid, it is impossible
 303   // to find a match.
 304   if (candidate->sdp_mid().empty() &&
 305       (candidate->sdp_mline_index() < 0 ||
 306        static_cast<size_t>(candidate->sdp_mline_index()) >=
 307            description_->contents().size())) {
 308     return false;
 309   }
 310
 311   if (candidate->sdp_mline_index() >= 0)
 312     *index = static_cast<size_t>(candidate->sdp_mline_index());
 313   if (description_ && !candidate->sdp_mid().empty()) {
 314     bool found = false;
 315     // Try to match the sdp_mid with content name.
 316     for (size_t i = 0; i < description_->contents().size(); ++i) {
 317       if (candidate->sdp_mid() == description_->contents().at(i).name) {
 318         *index = i;
 319         found = true;
 320         break;
 321       }
 322     }
 323     if (!found) {
 324       // If the sdp_mid is presented but we can't find a match, we consider
 325       // this as an error.
 326       return false;
 327     }
 328   }
 329   return true;
 330 }
 331
 332 int JsepSessionDescription::GetMediasectionIndex(const Candidate& candidate) {
 333   // Find the description with a matching transport name of the candidate.
 334   const std::string& transport_name = candidate.transport_name();
 335   for (size_t i = 0; i < description_->contents().size(); ++i) {
 336     if (transport_name == description_->contents().at(i).name) {
 337       return static_cast<int>(i);
 338     }
 339   }
 340   return -1;
 341 }
 342
 343 }  // namespace webrtc