| /* |
| * libjingle |
| * Copyright 2012 Google Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright notice, |
| * this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright notice, |
| * this list of conditions and the following disclaimer in the documentation |
| * and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED |
| * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
| * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
| * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "talk/p2p/base/transportdescriptionfactory.h" |
| |
| #include "talk/base/helpers.h" |
| #include "talk/base/logging.h" |
| #include "talk/base/messagedigest.h" |
| #include "talk/base/scoped_ptr.h" |
| #include "talk/base/sslfingerprint.h" |
| #include "talk/p2p/base/transportdescription.h" |
| |
| namespace cricket { |
| |
| static TransportProtocol kDefaultProtocol = ICEPROTO_GOOGLE; |
| static const char* kDefaultDigestAlg = talk_base::DIGEST_SHA_1; |
| |
| TransportDescriptionFactory::TransportDescriptionFactory() |
| : protocol_(kDefaultProtocol), |
| secure_(SEC_DISABLED), |
| identity_(NULL), |
| digest_alg_(kDefaultDigestAlg) { |
| } |
| |
| TransportDescription* TransportDescriptionFactory::CreateOffer( |
| const TransportOptions& options, |
| const TransportDescription* current_description) const { |
| talk_base::scoped_ptr<TransportDescription> desc(new TransportDescription()); |
| |
| // Set the transport type depending on the selected protocol. |
| if (protocol_ == ICEPROTO_RFC5245) { |
| desc->transport_type = NS_JINGLE_ICE_UDP; |
| } else if (protocol_ == ICEPROTO_HYBRID) { |
| desc->transport_type = NS_JINGLE_ICE_UDP; |
| desc->AddOption(ICE_OPTION_GICE); |
| } else if (protocol_ == ICEPROTO_GOOGLE) { |
| desc->transport_type = NS_GINGLE_P2P; |
| } |
| |
| // Generate the ICE credentials if we don't already have them. |
| if (!current_description || options.ice_restart) { |
| desc->ice_ufrag = talk_base::CreateRandomString(ICE_UFRAG_LENGTH); |
| desc->ice_pwd = talk_base::CreateRandomString(ICE_PWD_LENGTH); |
| } else { |
| desc->ice_ufrag = current_description->ice_ufrag; |
| desc->ice_pwd = current_description->ice_pwd; |
| } |
| |
| // 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.release(); |
| } |
| |
| TransportDescription* TransportDescriptionFactory::CreateAnswer( |
| const TransportDescription* offer, |
| const TransportOptions& options, |
| const TransportDescription* current_description) const { |
| // A NULL offer is treated as a GICE transport description. |
| // TODO(juberti): Figure out why we get NULL offers, and fix this upstream. |
| talk_base::scoped_ptr<TransportDescription> desc(new TransportDescription()); |
| |
| // Figure out which ICE variant to negotiate; prefer RFC 5245 ICE, but fall |
| // back to G-ICE if needed. Note that we never create a hybrid answer, since |
| // we know what the other side can support already. |
| if (offer && offer->transport_type == NS_JINGLE_ICE_UDP && |
| (protocol_ == ICEPROTO_RFC5245 || protocol_ == ICEPROTO_HYBRID)) { |
| // Offer is ICE or hybrid, we support ICE or hybrid: use ICE. |
| desc->transport_type = NS_JINGLE_ICE_UDP; |
| } else if (offer && offer->transport_type == NS_JINGLE_ICE_UDP && |
| offer->HasOption(ICE_OPTION_GICE) && |
| protocol_ == ICEPROTO_GOOGLE) { |
| desc->transport_type = NS_GINGLE_P2P; |
| // Offer is hybrid, we support GICE: use GICE. |
| } else if ((!offer || offer->transport_type == NS_GINGLE_P2P) && |
| (protocol_ == ICEPROTO_HYBRID || protocol_ == ICEPROTO_GOOGLE)) { |
| // Offer is GICE, we support hybrid or GICE: use GICE. |
| desc->transport_type = NS_GINGLE_P2P; |
| } else { |
| // Mismatch. |
| LOG(LS_WARNING) << "Failed to create TransportDescription answer " |
| "because of incompatible transport types"; |
| return NULL; |
| } |
| |
| // Generate the ICE credentials if we don't already have them or ice is |
| // being restarted. |
| if (!current_description || options.ice_restart) { |
| desc->ice_ufrag = talk_base::CreateRandomString(ICE_UFRAG_LENGTH); |
| desc->ice_pwd = talk_base::CreateRandomString(ICE_PWD_LENGTH); |
| } else { |
| desc->ice_ufrag = current_description->ice_ufrag; |
| desc->ice_pwd = current_description->ice_pwd; |
| } |
| |
| // 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) { |
| // Fail if we can't create the fingerprint. |
| // Setting DTLS role to active. |
| ConnectionRole role = (options.prefer_passive_role) ? |
| CONNECTIONROLE_PASSIVE : CONNECTIONROLE_ACTIVE; |
| |
| if (!SetSecurityInfo(desc.get(), role)) { |
| return NULL; |
| } |
| } |
| } else if (secure_ == SEC_REQUIRED) { |
| // We require DTLS, but the other side didn't offer it. Fail. |
| LOG(LS_WARNING) << "Failed to create TransportDescription answer " |
| "because of incompatible security settings"; |
| return NULL; |
| } |
| |
| return desc.release(); |
| } |
| |
| bool TransportDescriptionFactory::SetSecurityInfo( |
| TransportDescription* desc, ConnectionRole role) const { |
| if (!identity_) { |
| LOG(LS_ERROR) << "Cannot create identity digest with no identity"; |
| return false; |
| } |
| |
| desc->identity_fingerprint.reset( |
| talk_base::SSLFingerprint::Create(digest_alg_, identity_)); |
| if (!desc->identity_fingerprint.get()) { |
| LOG(LS_ERROR) << "Failed to create identity digest, alg=" << digest_alg_; |
| return false; |
| } |
| |
| // Assign security role. |
| desc->connection_role = role; |
| return true; |
| } |
| |
| } // namespace cricket |
| |