1/*
2 *  Copyright 2004 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 <utility>  // for std::pair
12
13#include "webrtc/p2p/base/transport.h"
14
15#include "webrtc/p2p/base/candidate.h"
16#include "webrtc/p2p/base/constants.h"
17#include "webrtc/p2p/base/port.h"
18#include "webrtc/p2p/base/transportchannelimpl.h"
19#include "webrtc/base/bind.h"
20#include "webrtc/base/checks.h"
21#include "webrtc/base/logging.h"
22
23namespace cricket {
24
25static bool VerifyIceParams(const TransportDescription& desc) {
26  // For legacy protocols.
27  if (desc.ice_ufrag.empty() && desc.ice_pwd.empty())
28    return true;
29
30  if (desc.ice_ufrag.length() < ICE_UFRAG_MIN_LENGTH ||
31      desc.ice_ufrag.length() > ICE_UFRAG_MAX_LENGTH) {
32    return false;
33  }
34  if (desc.ice_pwd.length() < ICE_PWD_MIN_LENGTH ||
35      desc.ice_pwd.length() > ICE_PWD_MAX_LENGTH) {
36    return false;
37  }
38  return true;
39}
40
41bool BadTransportDescription(const std::string& desc, std::string* err_desc) {
42  if (err_desc) {
43    *err_desc = desc;
44  }
45  LOG(LS_ERROR) << desc;
46  return false;
47}
48
49bool IceCredentialsChanged(const std::string& old_ufrag,
50                           const std::string& old_pwd,
51                           const std::string& new_ufrag,
52                           const std::string& new_pwd) {
53  // TODO(jiayl): The standard (RFC 5245 Section 9.1.1.1) says that ICE should
54  // restart when both the ufrag and password are changed, but we do restart
55  // when either ufrag or passwrod is changed to keep compatible with GICE. We
56  // should clean this up when GICE is no longer used.
57  return (old_ufrag != new_ufrag) || (old_pwd != new_pwd);
58}
59
60static bool IceCredentialsChanged(const TransportDescription& old_desc,
61                                  const TransportDescription& new_desc) {
62  return IceCredentialsChanged(old_desc.ice_ufrag, old_desc.ice_pwd,
63                               new_desc.ice_ufrag, new_desc.ice_pwd);
64}
65
66Transport::Transport(const std::string& name, PortAllocator* allocator)
67    : name_(name), allocator_(allocator) {}
68
69Transport::~Transport() {
70  RTC_DCHECK(channels_destroyed_);
71}
72
73void Transport::SetIceRole(IceRole role) {
74  ice_role_ = role;
75  for (const auto& kv : channels_) {
76    kv.second->SetIceRole(ice_role_);
77  }
78}
79
80bool Transport::GetRemoteSSLCertificate(rtc::SSLCertificate** cert) {
81  if (channels_.empty()) {
82    return false;
83  }
84
85  auto iter = channels_.begin();
86  return iter->second->GetRemoteSSLCertificate(cert);
87}
88
89void Transport::SetIceConfig(const IceConfig& config) {
90  ice_config_ = config;
91  for (const auto& kv : channels_) {
92    kv.second->SetIceConfig(ice_config_);
93  }
94}
95
96bool Transport::SetLocalTransportDescription(
97    const TransportDescription& description,
98    ContentAction action,
99    std::string* error_desc) {
100  bool ret = true;
101
102  if (!VerifyIceParams(description)) {
103    return BadTransportDescription("Invalid ice-ufrag or ice-pwd length",
104                                   error_desc);
105  }
106
107  if (local_description_ &&
108      IceCredentialsChanged(*local_description_, description)) {
109    IceRole new_ice_role =
110        (action == CA_OFFER) ? ICEROLE_CONTROLLING : ICEROLE_CONTROLLED;
111
112    // It must be called before ApplyLocalTransportDescription, which may
113    // trigger an ICE restart and depends on the new ICE role.
114    SetIceRole(new_ice_role);
115  }
116
117  local_description_.reset(new TransportDescription(description));
118
119  for (const auto& kv : channels_) {
120    ret &= ApplyLocalTransportDescription(kv.second, error_desc);
121  }
122  if (!ret) {
123    return false;
124  }
125
126  // If PRANSWER/ANSWER is set, we should decide transport protocol type.
127  if (action == CA_PRANSWER || action == CA_ANSWER) {
128    ret &= NegotiateTransportDescription(action, error_desc);
129  }
130  if (ret) {
131    local_description_set_ = true;
132    ConnectChannels();
133  }
134
135  return ret;
136}
137
138bool Transport::SetRemoteTransportDescription(
139    const TransportDescription& description,
140    ContentAction action,
141    std::string* error_desc) {
142  bool ret = true;
143
144  if (!VerifyIceParams(description)) {
145    return BadTransportDescription("Invalid ice-ufrag or ice-pwd length",
146                                   error_desc);
147  }
148
149  remote_description_.reset(new TransportDescription(description));
150  for (const auto& kv : channels_) {
151    ret &= ApplyRemoteTransportDescription(kv.second, error_desc);
152  }
153
154  // If PRANSWER/ANSWER is set, we should decide transport protocol type.
155  if (action == CA_PRANSWER || action == CA_ANSWER) {
156    ret = NegotiateTransportDescription(CA_OFFER, error_desc);
157  }
158  if (ret) {
159    remote_description_set_ = true;
160  }
161
162  return ret;
163}
164
165TransportChannelImpl* Transport::CreateChannel(int component) {
166  TransportChannelImpl* channel;
167
168  // Create the entry if it does not exist.
169  bool channel_exists = false;
170  auto iter = channels_.find(component);
171  if (iter == channels_.end()) {
172    channel = CreateTransportChannel(component);
173    channels_.insert(std::pair<int, TransportChannelImpl*>(component, channel));
174  } else {
175    channel = iter->second;
176    channel_exists = true;
177  }
178
179  channels_destroyed_ = false;
180
181  if (channel_exists) {
182    // If this is an existing channel, we should just return it.
183    return channel;
184  }
185
186  // Push down our transport state to the new channel.
187  channel->SetIceRole(ice_role_);
188  channel->SetIceTiebreaker(tiebreaker_);
189  channel->SetIceConfig(ice_config_);
190  // TODO(ronghuawu): Change CreateChannel to be able to return error since
191  // below Apply**Description calls can fail.
192  if (local_description_)
193    ApplyLocalTransportDescription(channel, nullptr);
194  if (remote_description_)
195    ApplyRemoteTransportDescription(channel, nullptr);
196  if (local_description_ && remote_description_)
197    ApplyNegotiatedTransportDescription(channel, nullptr);
198
199  if (connect_requested_) {
200    channel->Connect();
201  }
202  return channel;
203}
204
205TransportChannelImpl* Transport::GetChannel(int component) {
206  auto iter = channels_.find(component);
207  return (iter != channels_.end()) ? iter->second : nullptr;
208}
209
210bool Transport::HasChannels() {
211  return !channels_.empty();
212}
213
214void Transport::DestroyChannel(int component) {
215  auto iter = channels_.find(component);
216  if (iter == channels_.end())
217    return;
218
219  TransportChannelImpl* channel = iter->second;
220  channels_.erase(iter);
221  DestroyTransportChannel(channel);
222}
223
224void Transport::ConnectChannels() {
225  if (connect_requested_ || channels_.empty())
226    return;
227
228  connect_requested_ = true;
229
230  if (!local_description_) {
231    // TOOD(mallinath) : TransportDescription(TD) shouldn't be generated here.
232    // As Transport must know TD is offer or answer and cricket::Transport
233    // doesn't have the capability to decide it. This should be set by the
234    // Session.
235    // Session must generate local TD before remote candidates pushed when
236    // initiate request initiated by the remote.
237    LOG(LS_INFO) << "Transport::ConnectChannels: No local description has "
238                 << "been set. Will generate one.";
239    TransportDescription desc(
240        std::vector<std::string>(), rtc::CreateRandomString(ICE_UFRAG_LENGTH),
241        rtc::CreateRandomString(ICE_PWD_LENGTH), ICEMODE_FULL,
242        CONNECTIONROLE_NONE, nullptr, Candidates());
243    SetLocalTransportDescription(desc, CA_OFFER, nullptr);
244  }
245
246  CallChannels(&TransportChannelImpl::Connect);
247}
248
249void Transport::MaybeStartGathering() {
250  if (connect_requested_) {
251    CallChannels(&TransportChannelImpl::MaybeStartGathering);
252  }
253}
254
255void Transport::DestroyAllChannels() {
256  for (const auto& kv : channels_) {
257    DestroyTransportChannel(kv.second);
258  }
259  channels_.clear();
260  channels_destroyed_ = true;
261}
262
263void Transport::CallChannels(TransportChannelFunc func) {
264  for (const auto& kv : channels_) {
265    (kv.second->*func)();
266  }
267}
268
269bool Transport::VerifyCandidate(const Candidate& cand, std::string* error) {
270  // No address zero.
271  if (cand.address().IsNil() || cand.address().IsAnyIP()) {
272    *error = "candidate has address of zero";
273    return false;
274  }
275
276  // Disallow all ports below 1024, except for 80 and 443 on public addresses.
277  int port = cand.address().port();
278  if (cand.protocol() == TCP_PROTOCOL_NAME &&
279      (cand.tcptype() == TCPTYPE_ACTIVE_STR || port == 0)) {
280    // Expected for active-only candidates per
281    // http://tools.ietf.org/html/rfc6544#section-4.5 so no error.
282    // Libjingle clients emit port 0, in "active" mode.
283    return true;
284  }
285  if (port < 1024) {
286    if ((port != 80) && (port != 443)) {
287      *error = "candidate has port below 1024, but not 80 or 443";
288      return false;
289    }
290
291    if (cand.address().IsPrivateIP()) {
292      *error = "candidate has port of 80 or 443 with private IP address";
293      return false;
294    }
295  }
296
297  return true;
298}
299
300
301bool Transport::GetStats(TransportStats* stats) {
302  stats->transport_name = name();
303  stats->channel_stats.clear();
304  for (auto kv : channels_) {
305    TransportChannelImpl* channel = kv.second;
306    TransportChannelStats substats;
307    substats.component = channel->component();
308    channel->GetSrtpCryptoSuite(&substats.srtp_crypto_suite);
309    channel->GetSslCipherSuite(&substats.ssl_cipher_suite);
310    if (!channel->GetStats(&substats.connection_infos)) {
311      return false;
312    }
313    stats->channel_stats.push_back(substats);
314  }
315  return true;
316}
317
318bool Transport::AddRemoteCandidates(const std::vector<Candidate>& candidates,
319                                    std::string* error) {
320  ASSERT(!channels_destroyed_);
321  // Verify each candidate before passing down to transport layer.
322  for (const Candidate& cand : candidates) {
323    if (!VerifyCandidate(cand, error)) {
324      return false;
325    }
326    if (!HasChannel(cand.component())) {
327      *error = "Candidate has unknown component: " + cand.ToString() +
328               " for content: " + name();
329      return false;
330    }
331  }
332
333  for (const Candidate& candidate : candidates) {
334    TransportChannelImpl* channel = GetChannel(candidate.component());
335    if (channel != nullptr) {
336      channel->AddRemoteCandidate(candidate);
337    }
338  }
339  return true;
340}
341
342bool Transport::ApplyLocalTransportDescription(TransportChannelImpl* ch,
343                                               std::string* error_desc) {
344  ch->SetIceCredentials(local_description_->ice_ufrag,
345                        local_description_->ice_pwd);
346  return true;
347}
348
349bool Transport::ApplyRemoteTransportDescription(TransportChannelImpl* ch,
350                                                std::string* error_desc) {
351  ch->SetRemoteIceCredentials(remote_description_->ice_ufrag,
352                              remote_description_->ice_pwd);
353  return true;
354}
355
356bool Transport::ApplyNegotiatedTransportDescription(
357    TransportChannelImpl* channel,
358    std::string* error_desc) {
359  channel->SetRemoteIceMode(remote_ice_mode_);
360  return true;
361}
362
363bool Transport::NegotiateTransportDescription(ContentAction local_role,
364                                              std::string* error_desc) {
365  // TODO(ekr@rtfm.com): This is ICE-specific stuff. Refactor into
366  // P2PTransport.
367
368  // If transport is in ICEROLE_CONTROLLED and remote end point supports only
369  // ice_lite, this local end point should take CONTROLLING role.
370  if (ice_role_ == ICEROLE_CONTROLLED &&
371      remote_description_->ice_mode == ICEMODE_LITE) {
372    SetIceRole(ICEROLE_CONTROLLING);
373  }
374
375  // Update remote ice_mode to all existing channels.
376  remote_ice_mode_ = remote_description_->ice_mode;
377
378  // Now that we have negotiated everything, push it downward.
379  // Note that we cache the result so that if we have race conditions
380  // between future SetRemote/SetLocal invocations and new channel
381  // creation, we have the negotiation state saved until a new
382  // negotiation happens.
383  for (const auto& kv : channels_) {
384    if (!ApplyNegotiatedTransportDescription(kv.second, error_desc)) {
385      return false;
386    }
387  }
388  return true;
389}
390
391}  // namespace cricket
392