1 files changed, 151 insertions, 0 deletions
diff --git a/third_party/libwebrtc/p2p/base/transport_description_factory.cc b/third_party/libwebrtc/p2p/base/transport_description_factory.cc
new file mode 100644
index 0000000000..7eb21da166
--- /dev/null
+++ b/third_party/libwebrtc/p2p/base/transport_description_factory.cc
@@ -0,0 +1,151 @@
+/*
+ *  Copyright 2012 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/transport_description_factory.h"
+
+#include <stddef.h>
+
+#include <memory>
+#include <string>
+
+#include "p2p/base/transport_description.h"
+#include "rtc_base/logging.h"
+#include "rtc_base/ssl_fingerprint.h"
+
+namespace cricket {
+
+TransportDescriptionFactory::TransportDescriptionFactory(
+    const webrtc::FieldTrialsView& field_trials)
+    : secure_(SEC_DISABLED), field_trials_(field_trials) {}
+
+TransportDescriptionFactory::~TransportDescriptionFactory() = default;
+
+std::unique_ptr<TransportDescription> TransportDescriptionFactory::CreateOffer(
+    const TransportOptions& options,
+    const TransportDescription* current_description,
+    IceCredentialsIterator* ice_credentials) const {
+  auto desc = std::make_unique<TransportDescription>();
+
+  // Generate the ICE credentials if we don't already have them.
+  if (!current_description || options.ice_restart) {
+    IceParameters credentials = ice_credentials->GetIceCredentials();
+    desc->ice_ufrag = credentials.ufrag;
+    desc->ice_pwd = credentials.pwd;
+  } else {
+    desc->ice_ufrag = current_description->ice_ufrag;
+    desc->ice_pwd = current_description->ice_pwd;
+  }
+  desc->AddOption(ICE_OPTION_TRICKLE);
+  if (options.enable_ice_renomination) {
+    desc->AddOption(ICE_OPTION_RENOMINATION);
+  }
+
+  // If we are trying to establish a secure transport, add a fingerprint.
+  if (secure_ == SEC_ENABLED || secure_ == SEC_REQUIRED) {
+    // Fail if we can't create the fingerprint.
+    // If we are the initiator set role to "actpass".
+    if (!SetSecurityInfo(desc.get(), CONNECTIONROLE_ACTPASS)) {
+      return NULL;
+    }
+  }
+
+  return desc;
+}
+
+std::unique_ptr<TransportDescription> TransportDescriptionFactory::CreateAnswer(
+    const TransportDescription* offer,
+    const TransportOptions& options,
+    bool require_transport_attributes,
+    const TransportDescription* current_description,
+    IceCredentialsIterator* ice_credentials) const {
+  // TODO(juberti): Figure out why we get NULL offers, and fix this upstream.
+  if (!offer) {
+    RTC_LOG(LS_WARNING) << "Failed to create TransportDescription answer "
+                           "because offer is NULL";
+    return NULL;
+  }
+
+  auto desc = std::make_unique<TransportDescription>();
+  // Generate the ICE credentials if we don't already have them or ice is
+  // being restarted.
+  if (!current_description || options.ice_restart) {
+    IceParameters credentials = ice_credentials->GetIceCredentials();
+    desc->ice_ufrag = credentials.ufrag;
+    desc->ice_pwd = credentials.pwd;
+  } else {
+    desc->ice_ufrag = current_description->ice_ufrag;
+    desc->ice_pwd = current_description->ice_pwd;
+  }
+  desc->AddOption(ICE_OPTION_TRICKLE);
+  if (options.enable_ice_renomination) {
+    desc->AddOption(ICE_OPTION_RENOMINATION);
+  }
+
+  // Negotiate security params.
+  if (offer && offer->identity_fingerprint.get()) {
+    // The offer supports DTLS, so answer with DTLS, as long as we support it.
+    if (secure_ == SEC_ENABLED || secure_ == SEC_REQUIRED) {
+      ConnectionRole role = CONNECTIONROLE_NONE;
+      // If the offer does not constrain the role, go with preference.
+      if (offer->connection_role == CONNECTIONROLE_ACTPASS) {
+        role = (options.prefer_passive_role) ? CONNECTIONROLE_PASSIVE
+                                             : CONNECTIONROLE_ACTIVE;
+      } else if (offer->connection_role == CONNECTIONROLE_ACTIVE) {
+        role = CONNECTIONROLE_PASSIVE;
+      } else if (offer->connection_role == CONNECTIONROLE_PASSIVE) {
+        role = CONNECTIONROLE_ACTIVE;
+      } else if (offer->connection_role == CONNECTIONROLE_NONE) {
+        // This case may be reached if a=setup is not present in the SDP.
+        RTC_LOG(LS_WARNING) << "Remote offer connection role is NONE, which is "
+                               "a protocol violation";
+        role = (options.prefer_passive_role) ? CONNECTIONROLE_PASSIVE
+                                             : CONNECTIONROLE_ACTIVE;
+      } else {
+        RTC_LOG(LS_ERROR) << "Remote offer connection role is " << role
+                          << " which is a protocol violation";
+        RTC_DCHECK_NOTREACHED();
+      }
+
+      if (!SetSecurityInfo(desc.get(), role)) {
+        return NULL;
+      }
+    }
+  } else if (require_transport_attributes && secure_ == SEC_REQUIRED) {
+    // We require DTLS, but the other side didn't offer it. Fail.
+    RTC_LOG(LS_WARNING) << "Failed to create TransportDescription answer "
+                           "because of incompatible security settings";
+    return NULL;
+  }
+
+  return desc;
+}
+
+bool TransportDescriptionFactory::SetSecurityInfo(TransportDescription* desc,
+                                                  ConnectionRole role) const {
+  if (!certificate_) {
+    RTC_LOG(LS_ERROR) << "Cannot create identity digest with no certificate";
+    return false;
+  }
+
+  // This digest algorithm is used to produce the a=fingerprint lines in SDP.
+  // RFC 4572 Section 5 requires that those lines use the same hash function as
+  // the certificate's signature, which is what CreateFromCertificate does.
+  desc->identity_fingerprint =
+      rtc::SSLFingerprint::CreateFromCertificate(*certificate_);
+  if (!desc->identity_fingerprint) {
+    return false;
+  }
+
+  // Assign security role.
+  desc->connection_role = role;
+  return true;
+}
+
+}  // namespace cricket