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gerrit-public.fairphone.software / platform / external / webrtc / 19f27e6a24f877fc2b0409a94b02d5f40ba3dc8c / . / talk / app / webrtc / webrtcsdp.cc
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/*
* libjingle
* Copyright 2011, Google Inc.
*
* 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/app/webrtc/webrtcsdp.h"
#include <limits.h>
#include <stdio.h>
#include <algorithm>
#include <string>
#include <vector>
#include "talk/app/webrtc/jsepicecandidate.h"
#include "talk/app/webrtc/jsepsessiondescription.h"
#include "talk/base/common.h"
#include "talk/base/logging.h"
#include "talk/base/messagedigest.h"
#include "talk/base/stringutils.h"
#include "talk/media/base/codec.h"
#include "talk/media/base/constants.h"
#include "talk/media/base/cryptoparams.h"
#include "talk/media/sctp/sctpdataengine.h"
#include "talk/p2p/base/candidate.h"
#include "talk/p2p/base/constants.h"
#include "talk/p2p/base/port.h"
#include "talk/session/media/mediasession.h"
#include "talk/session/media/mediasessionclient.h"
using cricket::AudioContentDescription;
using cricket::Candidate;
using cricket::Candidates;
using cricket::ContentDescription;
using cricket::ContentInfo;
using cricket::CryptoParams;
using cricket::DataContentDescription;
using cricket::ICE_CANDIDATE_COMPONENT_RTP;
using cricket::ICE_CANDIDATE_COMPONENT_RTCP;
using cricket::kCodecParamMaxBitrate;
using cricket::kCodecParamMaxPTime;
using cricket::kCodecParamMaxQuantization;
using cricket::kCodecParamMinBitrate;
using cricket::kCodecParamMinPTime;
using cricket::kCodecParamPTime;
using cricket::kCodecParamSPropStereo;
using cricket::kCodecParamStereo;
using cricket::kCodecParamUseInbandFec;
using cricket::kCodecParamSctpProtocol;
using cricket::kCodecParamSctpStreams;
using cricket::kCodecParamMaxAverageBitrate;
using cricket::kWildcardPayloadType;
using cricket::MediaContentDescription;
using cricket::MediaType;
using cricket::NS_JINGLE_ICE_UDP;
using cricket::RtpHeaderExtension;
using cricket::SsrcGroup;
using cricket::StreamParams;
using cricket::StreamParamsVec;
using cricket::TransportDescription;
using cricket::TransportInfo;
using cricket::VideoContentDescription;
using talk_base::SocketAddress;
typedef std::vector<RtpHeaderExtension> RtpHeaderExtensions;
namespace cricket {
class SessionDescription;
}
namespace webrtc {
// Line type
// RFC 4566
// An SDP session description consists of a number of lines of text of
// the form:
// <type>=<value>
// where <type> MUST be exactly one case-significant character.
static const int kLinePrefixLength = 2; // Lenght of <type>=
static const char kLineTypeVersion = 'v';
static const char kLineTypeOrigin = 'o';
static const char kLineTypeSessionName = 's';
static const char kLineTypeSessionInfo = 'i';
static const char kLineTypeSessionUri = 'u';
static const char kLineTypeSessionEmail = 'e';
static const char kLineTypeSessionPhone = 'p';
static const char kLineTypeSessionBandwidth = 'b';
static const char kLineTypeTiming = 't';
static const char kLineTypeRepeatTimes = 'r';
static const char kLineTypeTimeZone = 'z';
static const char kLineTypeEncryptionKey = 'k';
static const char kLineTypeMedia = 'm';
static const char kLineTypeConnection = 'c';
static const char kLineTypeAttributes = 'a';
// Attributes
static const char kAttributeGroup[] = "group";
static const char kAttributeMid[] = "mid";
static const char kAttributeRtcpMux[] = "rtcp-mux";
static const char kAttributeSsrc[] = "ssrc";
static const char kSsrcAttributeCname[] = "cname";
static const char kAttributeExtmap[] = "extmap";
// draft-alvestrand-mmusic-msid-01
// a=msid-semantic: WMS
static const char kAttributeMsidSemantics[] = "msid-semantic";
static const char kMediaStreamSemantic[] = "WMS";
static const char kSsrcAttributeMsid[] = "msid";
static const char kDefaultMsid[] = "default";
static const char kMsidAppdataAudio[] = "a";
static const char kMsidAppdataVideo[] = "v";
static const char kMsidAppdataData[] = "d";
static const char kSsrcAttributeMslabel[] = "mslabel";
static const char kSSrcAttributeLabel[] = "label";
static const char kAttributeSsrcGroup[] = "ssrc-group";
static const char kAttributeCrypto[] = "crypto";
static const char kAttributeCandidate[] = "candidate";
static const char kAttributeCandidateTyp[] = "typ";
static const char kAttributeCandidateRaddr[] = "raddr";
static const char kAttributeCandidateRport[] = "rport";
static const char kAttributeCandidateUsername[] = "username";
static const char kAttributeCandidatePassword[] = "password";
static const char kAttributeCandidateGeneration[] = "generation";
static const char kAttributeFingerprint[] = "fingerprint";
static const char kAttributeSetup[] = "setup";
static const char kAttributeFmtp[] = "fmtp";
static const char kAttributeRtpmap[] = "rtpmap";
static const char kAttributeSctpmap[] = "sctpmap";
static const char kAttributeRtcp[] = "rtcp";
static const char kAttributeIceUfrag[] = "ice-ufrag";
static const char kAttributeIcePwd[] = "ice-pwd";
static const char kAttributeIceLite[] = "ice-lite";
static const char kAttributeIceOption[] = "ice-options";
static const char kAttributeSendOnly[] = "sendonly";
static const char kAttributeRecvOnly[] = "recvonly";
static const char kAttributeRtcpFb[] = "rtcp-fb";
static const char kAttributeSendRecv[] = "sendrecv";
static const char kAttributeInactive[] = "inactive";
// Experimental flags
static const char kAttributeXGoogleFlag[] = "x-google-flag";
static const char kValueConference[] = "conference";
static const char kAttributeXGoogleBufferLatency[] =
"x-google-buffer-latency";
// Candidate
static const char kCandidateHost[] = "host";
static const char kCandidateSrflx[] = "srflx";
// TODO: How to map the prflx with circket candidate type
// static const char kCandidatePrflx[] = "prflx";
static const char kCandidateRelay[] = "relay";
static const char kSdpDelimiterEqual = '=';
static const char kSdpDelimiterSpace = ' ';
static const char kSdpDelimiterColon = ':';
static const char kSdpDelimiterSemicolon = ';';
static const char kSdpDelimiterSlash = '/';
static const char kNewLine = '\n';
static const char kReturn = '\r';
static const char kLineBreak[] = "\r\n";
// TODO: Generate the Session and Time description
// instead of hardcoding.
static const char kSessionVersion[] = "v=0";
// RFC 4566
static const char kSessionOriginUsername[] = "-";
static const char kSessionOriginSessionId[] = "0";
static const char kSessionOriginSessionVersion[] = "0";
static const char kSessionOriginNettype[] = "IN";
static const char kSessionOriginAddrtype[] = "IP4";
static const char kSessionOriginAddress[] = "127.0.0.1";
static const char kSessionName[] = "s=-";
static const char kTimeDescription[] = "t=0 0";
static const char kAttrGroup[] = "a=group:BUNDLE";
static const char kConnectionNettype[] = "IN";
static const char kConnectionAddrtype[] = "IP4";
static const char kMediaTypeVideo[] = "video";
static const char kMediaTypeAudio[] = "audio";
static const char kMediaTypeData[] = "application";
static const char kMediaPortRejected[] = "0";
static const char kDefaultAddress[] = "0.0.0.0";
static const char kDefaultPort[] = "1";
// RFC 3556
static const char kApplicationSpecificMaximum[] = "AS";
static const int kDefaultVideoClockrate = 90000;
// ISAC special-case.
static const char kIsacCodecName[] = "ISAC"; // From webrtcvoiceengine.cc
static const int kIsacWbDefaultRate = 32000; // From acm_common_defs.h
static const int kIsacSwbDefaultRate = 56000; // From acm_common_defs.h
static const int kDefaultSctpFmt = 5000;
static const char kDefaultSctpmapProtocol[] = "webrtc-datachannel";
struct SsrcInfo {
SsrcInfo()
: msid_identifier(kDefaultMsid),
// TODO(ronghuawu): What should we do if the appdata doesn't appear?
// Create random string (which will be used as track label later)?
msid_appdata(talk_base::CreateRandomString(8)) {
}
uint32 ssrc_id;
std::string cname;
std::string msid_identifier;
std::string msid_appdata;
// For backward compatibility.
// TODO(ronghuawu): Remove below 2 fields once all the clients support msid.
std::string label;
std::string mslabel;
};
typedef std::vector<SsrcInfo> SsrcInfoVec;
typedef std::vector<SsrcGroup> SsrcGroupVec;
// Serializes the passed in SessionDescription to a SDP string.
// desc - The SessionDescription object to be serialized.
static std::string SdpSerializeSessionDescription(
const JsepSessionDescription& jdesc);
template <class T>
static void AddFmtpLine(const T& codec, std::string* message);
static void BuildMediaDescription(const ContentInfo* content_info,
const TransportInfo* transport_info,
const MediaType media_type,
std::string* message);
static void BuildSctpContentAttributes(std::string* message);
static void BuildRtpContentAttributes(
const MediaContentDescription* media_desc,
const MediaType media_type,
std::string* message);
static void BuildRtpMap(const MediaContentDescription* media_desc,
const MediaType media_type,
std::string* message);
static void BuildCandidate(const std::vector<Candidate>& candidates,
std::string* message);
static void BuildIceOptions(const std::vector<std::string>& transport_options,
std::string* message);
static bool ParseSessionDescription(const std::string& message, size_t* pos,
std::string* session_id,
std::string* session_version,
bool* supports_msid,
TransportDescription* session_td,
RtpHeaderExtensions* session_extmaps,
cricket::SessionDescription* desc,
SdpParseError* error);
static bool ParseGroupAttribute(const std::string& line,
cricket::SessionDescription* desc,
SdpParseError* error);
static bool ParseMediaDescription(
const std::string& message,
const TransportDescription& session_td,
const RtpHeaderExtensions& session_extmaps,
bool supports_msid,
size_t* pos, cricket::SessionDescription* desc,
std::vector<JsepIceCandidate*>* candidates,
SdpParseError* error);
static bool ParseContent(const std::string& message,
const MediaType media_type,
int mline_index,
const std::string& protocol,
const std::vector<int>& codec_preference,
size_t* pos,
std::string* content_name,
MediaContentDescription* media_desc,
TransportDescription* transport,
std::vector<JsepIceCandidate*>* candidates,
SdpParseError* error);
static bool ParseSsrcAttribute(const std::string& line,
SsrcInfoVec* ssrc_infos,
SdpParseError* error);
static bool ParseSsrcGroupAttribute(const std::string& line,
SsrcGroupVec* ssrc_groups,
SdpParseError* error);
static bool ParseCryptoAttribute(const std::string& line,
MediaContentDescription* media_desc,
SdpParseError* error);
static bool ParseRtpmapAttribute(const std::string& line,
const MediaType media_type,
const std::vector<int>& codec_preference,
MediaContentDescription* media_desc,
SdpParseError* error);
static bool ParseFmtpAttributes(const std::string& line,
const MediaType media_type,
MediaContentDescription* media_desc,
SdpParseError* error);
static bool ParseFmtpParam(const std::string& line, std::string* parameter,
std::string* value, SdpParseError* error);
static bool ParseCandidate(const std::string& message, Candidate* candidate,
SdpParseError* error, bool is_raw);
static bool ParseRtcpFbAttribute(const std::string& line,
const MediaType media_type,
MediaContentDescription* media_desc,
SdpParseError* error);
static bool ParseIceOptions(const std::string& line,
std::vector<std::string>* transport_options,
SdpParseError* error);
static bool ParseExtmap(const std::string& line,
RtpHeaderExtension* extmap,
SdpParseError* error);
static bool ParseFingerprintAttribute(const std::string& line,
talk_base::SSLFingerprint** fingerprint,
SdpParseError* error);
static bool ParseDtlsSetup(const std::string& line,
cricket::ConnectionRole* role,
SdpParseError* error);
// Helper functions
// Below ParseFailed*** functions output the line that caused the parsing
// failure and the detailed reason (|description|) of the failure to |error|.
// The functions always return false so that they can be used directly in the
// following way when error happens:
// "return ParseFailed***(...);"
// The line starting at |line_start| of |message| is the failing line.
// The reason for the failure should be provided in the |description|.
// An example of a description could be "unknown character".
static bool ParseFailed(const std::string& message,
size_t line_start,
const std::string& description,
SdpParseError* error) {
// Get the first line of |message| from |line_start|.
std::string first_line = message;
size_t line_end = message.find(kNewLine, line_start);
if (line_end != std::string::npos) {
if (line_end > 0 && (message.at(line_end - 1) == kReturn)) {
--line_end;
}
first_line = message.substr(line_start, (line_end - line_start));
}
if (error) {
error->line = first_line;
error->description = description;
}
LOG(LS_ERROR) << "Failed to parse: \"" << first_line
<< "\". Reason: " << description;
return false;
}
// |line| is the failing line. The reason for the failure should be
// provided in the |description|.
static bool ParseFailed(const std::string& line,
const std::string& description,
SdpParseError* error) {
return ParseFailed(line, 0, description, error);
}
// Parses failure where the failing SDP line isn't know or there are multiple
// failing lines.
static bool ParseFailed(const std::string& description,
SdpParseError* error) {
return ParseFailed("", description, error);
}
// |line| is the failing line. The failure is due to the fact that |line|
// doesn't have |expected_fields| fields.
static bool ParseFailedExpectFieldNum(const std::string& line,
int expected_fields,
SdpParseError* error) {
std::ostringstream description;
description << "Expects " << expected_fields << " fields.";
return ParseFailed(line, description.str(), error);
}
// |line| is the failing line. The failure is due to the fact that |line| has
// less than |expected_min_fields| fields.
static bool ParseFailedExpectMinFieldNum(const std::string& line,
int expected_min_fields,
SdpParseError* error) {
std::ostringstream description;
description << "Expects at least " << expected_min_fields << " fields.";
return ParseFailed(line, description.str(), error);
}
// |line| is the failing line. The failure is due to the fact that it failed to
// get the value of |attribute|.
static bool ParseFailedGetValue(const std::string& line,
const std::string& attribute,
SdpParseError* error) {
std::ostringstream description;
description << "Failed to get the value of attribute: " << attribute;
return ParseFailed(line, description.str(), error);
}
// The line starting at |line_start| of |message| is the failing line. The
// failure is due to the line type (e.g. the "m" part of the "m-line")
// not matching what is expected. The expected line type should be
// provided as |line_type|.
static bool ParseFailedExpectLine(const std::string& message,
size_t line_start,
const char line_type,
const std::string& line_value,
SdpParseError* error) {
std::ostringstream description;
description << "Expect line: " << line_type << "=" << line_value;
return ParseFailed(message, line_start, description.str(), error);
}
static bool AddLine(const std::string& line, std::string* message) {
if (!message)
return false;
message->append(line);
message->append(kLineBreak);
return true;
}
static bool GetLine(const std::string& message,
size_t* pos,
std::string* line) {
size_t line_begin = *pos;
size_t line_end = message.find(kNewLine, line_begin);
if (line_end == std::string::npos) {
return false;
}
// Update the new start position
*pos = line_end + 1;
if (line_end > 0 && (message.at(line_end - 1) == kReturn)) {
--line_end;
}
*line = message.substr(line_begin, (line_end - line_begin));
const char* cline = line->c_str();
// RFC 4566
// An SDP session description consists of a number of lines of text of
// the form:
// <type>=<value>
// where <type> MUST be exactly one case-significant character and
// <value> is structured text whose format depends on <type>.
// Whitespace MUST NOT be used on either side of the "=" sign.
if (cline[0] == kSdpDelimiterSpace ||
cline[1] != kSdpDelimiterEqual ||
cline[2] == kSdpDelimiterSpace) {
*pos = line_begin;
return false;
}
return true;
}
// Init |os| to "|type|=|value|".
static void InitLine(const char type,
const std::string& value,
std::ostringstream* os) {
os->str("");
*os << type << kSdpDelimiterEqual << value;
}
// Init |os| to "a=|attribute|".
static void InitAttrLine(const std::string& attribute, std::ostringstream* os) {
InitLine(kLineTypeAttributes, attribute, os);
}
// Writes a SDP attribute line based on |attribute| and |value| to |message|.
static void AddAttributeLine(const std::string& attribute, int value,
std::string* message) {
std::ostringstream os;
InitAttrLine(attribute, &os);
os << kSdpDelimiterColon << value;
AddLine(os.str(), message);
}
// Returns the first line of the message without the line breaker.
static bool GetFirstLine(const std::string& message, std::string* line) {
size_t pos = 0;
if (!GetLine(message, &pos, line)) {
// If GetLine failed, just return the full |message|.
*line = message;
}
return true;
}
static bool IsLineType(const std::string& message,
const char type,
size_t line_start) {
if (message.size() < line_start + kLinePrefixLength) {
return false;
}
const char* cmessage = message.c_str();
return (cmessage[line_start] == type &&
cmessage[line_start + 1] == kSdpDelimiterEqual);
}
static bool IsLineType(const std::string& line,
const char type) {
return IsLineType(line, type, 0);
}
static bool GetLineWithType(const std::string& message, size_t* pos,
std::string* line, const char type) {
if (!IsLineType(message, type, *pos)) {
return false;
}
if (!GetLine(message, pos, line))
return false;
return true;
}
static bool HasAttribute(const std::string& line,
const std::string& attribute) {
return (line.compare(kLinePrefixLength, attribute.size(), attribute) == 0);
}
// Verifies the candiate to be of the format candidate:<blah>
static bool IsRawCandidate(const std::string& line) {
// Checking candiadte-attribute is starting with "candidate" str.
if (line.compare(0, strlen(kAttributeCandidate), kAttributeCandidate) != 0) {
return false;
}
const size_t first_candidate = line.find(kSdpDelimiterColon);
if (first_candidate == std::string::npos)
return false;
// In this format we only expecting one candiate. If any additional
// candidates present, whole string will be discared.
const size_t any_other = line.find(kSdpDelimiterColon, first_candidate + 1);
return (any_other == std::string::npos);
}
static bool AddSsrcLine(uint32 ssrc_id, const std::string& attribute,
const std::string& value, std::string* message) {
// RFC 5576
// a=ssrc:<ssrc-id> <attribute>:<value>
std::ostringstream os;
InitAttrLine(kAttributeSsrc, &os);
os << kSdpDelimiterColon << ssrc_id << kSdpDelimiterSpace
<< attribute << kSdpDelimiterColon << value;
return AddLine(os.str(), message);
}
// Split the message into two parts by the first delimiter.
static bool SplitByDelimiter(const std::string& message,
const char delimiter,
std::string* field1,
std::string* field2) {
// Find the first delimiter
size_t pos = message.find(delimiter);
if (pos == std::string::npos) {
return false;
}
*field1 = message.substr(0, pos);
// The rest is the value.
*field2 = message.substr(pos + 1);
return true;
}
// Get value only from <attribute>:<value>.
static bool GetValue(const std::string& message, const std::string& attribute,
std::string* value, SdpParseError* error) {
std::string leftpart;
if (!SplitByDelimiter(message, kSdpDelimiterColon, &leftpart, value)) {
return ParseFailedGetValue(message, attribute, error);
}
// The left part should end with the expected attribute.
if (leftpart.length() < attribute.length() ||
leftpart.compare(leftpart.length() - attribute.length(),
attribute.length(), attribute) != 0) {
return ParseFailedGetValue(message, attribute, error);
}
return true;
}
static bool CaseInsensitiveFind(std::string str1, std::string str2) {
std::transform(str1.begin(), str1.end(), str1.begin(),
::tolower);
std::transform(str2.begin(), str2.end(), str2.begin(),
::tolower);
return str1.find(str2) != std::string::npos;
}
void CreateTracksFromSsrcInfos(const SsrcInfoVec& ssrc_infos,
StreamParamsVec* tracks) {
ASSERT(tracks != NULL);
for (SsrcInfoVec::const_iterator ssrc_info = ssrc_infos.begin();
ssrc_info != ssrc_infos.end(); ++ssrc_info) {
if (ssrc_info->cname.empty()) {
continue;
}
std::string sync_label;
std::string track_id;
if (ssrc_info->msid_identifier == kDefaultMsid &&
!ssrc_info->mslabel.empty()) {
// If there's no msid and there's mslabel, we consider this is a sdp from
// a older version of client that doesn't support msid.
// In that case, we use the mslabel and label to construct the track.
sync_label = ssrc_info->mslabel;
track_id = ssrc_info->label;
} else {
sync_label = ssrc_info->msid_identifier;
// The appdata consists of the "id" attribute of a MediaStreamTrack, which
// is corresponding to the "id" attribute of StreamParams.
track_id = ssrc_info->msid_appdata;
}
if (sync_label.empty() || track_id.empty()) {
ASSERT(false);
continue;
}
StreamParamsVec::iterator track = tracks->begin();
for (; track != tracks->end(); ++track) {
if (track->id == track_id) {
break;
}
}
if (track == tracks->end()) {
// If we don't find an existing track, create a new one.
tracks->push_back(StreamParams());
track = tracks->end() - 1;
}
track->add_ssrc(ssrc_info->ssrc_id);
track->cname = ssrc_info->cname;
track->sync_label = sync_label;
track->id = track_id;
}
}
void GetMediaStreamLabels(const ContentInfo* content,
std::set<std::string>* labels) {
const MediaContentDescription* media_desc =
static_cast<const MediaContentDescription*>(
content->description);
const cricket::StreamParamsVec& streams = media_desc->streams();
for (cricket::StreamParamsVec::const_iterator it = streams.begin();
it != streams.end(); ++it) {
labels->insert(it->sync_label);
}
}
// RFC 5245
// It is RECOMMENDED that default candidates be chosen based on the
// likelihood of those candidates to work with the peer that is being
// contacted. It is RECOMMENDED that relayed > reflexive > host.
static const int kPreferenceUnknown = 0;
static const int kPreferenceHost = 1;
static const int kPreferenceReflexive = 2;
static const int kPreferenceRelayed = 3;
static int GetCandidatePreferenceFromType(const std::string& type) {
int preference = kPreferenceUnknown;
if (type == cricket::LOCAL_PORT_TYPE) {
preference = kPreferenceHost;
} else if (type == cricket::STUN_PORT_TYPE) {
preference = kPreferenceReflexive;
} else if (type == cricket::RELAY_PORT_TYPE) {
preference = kPreferenceRelayed;
} else {
ASSERT(false);
}
return preference;
}
// Get ip and port of the default destination from the |candidates| with
// the given value of |component_id|.
// RFC 5245
// The value of |component_id| currently supported are 1 (RTP) and 2 (RTCP).
// TODO: Decide the default destination in webrtcsession and
// pass it down via SessionDescription.
static bool GetDefaultDestination(const std::vector<Candidate>& candidates,
int component_id, std::string* port, std::string* ip) {
*port = kDefaultPort;
*ip = kDefaultAddress;
int current_preference = kPreferenceUnknown;
for (std::vector<Candidate>::const_iterator it = candidates.begin();
it != candidates.end(); ++it) {
if (it->component() != component_id) {
continue;
}
const int preference = GetCandidatePreferenceFromType(it->type());
// See if this candidate is more preferable then the current one.
if (preference <= current_preference) {
continue;
}
current_preference = preference;
*port = it->address().PortAsString();
*ip = it->address().ipaddr().ToString();
}
return true;
}
// Update the media default destination.
static void UpdateMediaDefaultDestination(
const std::vector<Candidate>& candidates, std::string* mline) {
// RFC 4566
// m=<media> <port> <proto> <fmt> ...
std::vector<std::string> fields;
talk_base::split(*mline, kSdpDelimiterSpace, &fields);
if (fields.size() < 3) {
return;
}
bool is_rtp =
fields[2].empty() ||
talk_base::starts_with(fields[2].data(),
cricket::kMediaProtocolRtpPrefix);
std::ostringstream os;
std::string rtp_port, rtp_ip;
if (GetDefaultDestination(candidates, ICE_CANDIDATE_COMPONENT_RTP,
&rtp_port, &rtp_ip)) {
// Found default RTP candidate.
// RFC 5245
// The default candidates are added to the SDP as the default
// destination for media. For streams based on RTP, this is done by
// placing the IP address and port of the RTP candidate into the c and m
// lines, respectively.
// Update the port in the m line.
// If this is a m-line with port equal to 0, we don't change it.
if (fields[1] != kMediaPortRejected) {
mline->replace(fields[0].size() + 1,
fields[1].size(),
rtp_port);
}
// Add the c line.
// RFC 4566
// c=<nettype> <addrtype> <connection-address>
InitLine(kLineTypeConnection, kConnectionNettype, &os);
os << " " << kConnectionAddrtype << " " << rtp_ip;
AddLine(os.str(), mline);
}
if (is_rtp) {
std::string rtcp_port, rtcp_ip;
if (GetDefaultDestination(candidates, ICE_CANDIDATE_COMPONENT_RTCP,
&rtcp_port, &rtcp_ip)) {
// Found default RTCP candidate.
// RFC 5245
// If the agent is utilizing RTCP, it MUST encode the RTCP candidate
// using the a=rtcp attribute as defined in RFC 3605.
// RFC 3605
// rtcp-attribute = "a=rtcp:" port [nettype space addrtype space
// connection-address] CRLF
InitAttrLine(kAttributeRtcp, &os);
os << kSdpDelimiterColon
<< rtcp_port << " "
<< kConnectionNettype << " "
<< kConnectionAddrtype << " "
<< rtcp_ip;
AddLine(os.str(), mline);
}
}
}
// Get candidates according to the mline index from SessionDescriptionInterface.
static void GetCandidatesByMindex(const SessionDescriptionInterface& desci,
int mline_index,
std::vector<Candidate>* candidates) {
if (!candidates) {
return;
}
const IceCandidateCollection* cc = desci.candidates(mline_index);
for (size_t i = 0; i < cc->count(); ++i) {
const IceCandidateInterface* candidate = cc->at(i);
candidates->push_back(candidate->candidate());
}
}
std::string SdpSerialize(const JsepSessionDescription& jdesc) {
std::string sdp = SdpSerializeSessionDescription(jdesc);
std::string sdp_with_candidates;
size_t pos = 0;
std::string line;
int mline_index = -1;
while (GetLine(sdp, &pos, &line)) {
if (IsLineType(line, kLineTypeMedia)) {
++mline_index;
std::vector<Candidate> candidates;
GetCandidatesByMindex(jdesc, mline_index, &candidates);
// Media line may append other lines inside the
// UpdateMediaDefaultDestination call, so add the kLineBreak here first.
line.append(kLineBreak);
UpdateMediaDefaultDestination(candidates, &line);
sdp_with_candidates.append(line);
// Build the a=candidate lines.
BuildCandidate(candidates, &sdp_with_candidates);
} else {
// Copy old line to new sdp without change.
AddLine(line, &sdp_with_candidates);
}
}
sdp = sdp_with_candidates;
return sdp;
}
std::string SdpSerializeSessionDescription(
const JsepSessionDescription& jdesc) {
const cricket::SessionDescription* desc = jdesc.description();
if (!desc) {
return "";
}
std::string message;
// Session Description.
AddLine(kSessionVersion, &message);
// Session Origin
// RFC 4566
// o=<username> <sess-id> <sess-version> <nettype> <addrtype>
// <unicast-address>
std::ostringstream os;
InitLine(kLineTypeOrigin, kSessionOriginUsername, &os);
const std::string session_id = jdesc.session_id().empty() ?
kSessionOriginSessionId : jdesc.session_id();
const std::string session_version = jdesc.session_version().empty() ?
kSessionOriginSessionVersion : jdesc.session_version();
os << " " << session_id << " " << session_version << " "
<< kSessionOriginNettype << " " << kSessionOriginAddrtype << " "
<< kSessionOriginAddress;
AddLine(os.str(), &message);
AddLine(kSessionName, &message);
// Time Description.
AddLine(kTimeDescription, &message);
// Group
if (desc->HasGroup(cricket::GROUP_TYPE_BUNDLE)) {
std::string group_line = kAttrGroup;
const cricket::ContentGroup* group =
desc->GetGroupByName(cricket::GROUP_TYPE_BUNDLE);
ASSERT(group != NULL);
const cricket::ContentNames& content_names = group->content_names();
for (cricket::ContentNames::const_iterator it = content_names.begin();
it != content_names.end(); ++it) {
group_line.append(" ");
group_line.append(*it);
}
AddLine(group_line, &message);
}
// MediaStream semantics
InitAttrLine(kAttributeMsidSemantics, &os);
os << kSdpDelimiterColon << " " << kMediaStreamSemantic;
std::set<std::string> media_stream_labels;
const ContentInfo* audio_content = GetFirstAudioContent(desc);
if (audio_content)
GetMediaStreamLabels(audio_content, &media_stream_labels);
const ContentInfo* video_content = GetFirstVideoContent(desc);
if (video_content)
GetMediaStreamLabels(video_content, &media_stream_labels);
for (std::set<std::string>::const_iterator it =
media_stream_labels.begin(); it != media_stream_labels.end(); ++it) {
os << " " << *it;
}
AddLine(os.str(), &message);
if (audio_content) {
BuildMediaDescription(audio_content,
desc->GetTransportInfoByName(audio_content->name),
cricket::MEDIA_TYPE_AUDIO, &message);
}
if (video_content) {
BuildMediaDescription(video_content,
desc->GetTransportInfoByName(video_content->name),
cricket::MEDIA_TYPE_VIDEO, &message);
}
const ContentInfo* data_content = GetFirstDataContent(desc);
if (data_content) {
BuildMediaDescription(data_content,
desc->GetTransportInfoByName(data_content->name),
cricket::MEDIA_TYPE_DATA, &message);
}
return message;
}
// Serializes the passed in IceCandidateInterface to a SDP string.
// candidate - The candidate to be serialized.
std::string SdpSerializeCandidate(
const IceCandidateInterface& candidate) {
std::string message;
std::vector<cricket::Candidate> candidates;
candidates.push_back(candidate.candidate());
BuildCandidate(candidates, &message);
return message;
}
bool SdpDeserialize(const std::string& message,
JsepSessionDescription* jdesc,
SdpParseError* error) {
std::string session_id;
std::string session_version;
TransportDescription session_td(NS_JINGLE_ICE_UDP,
std::string(), std::string());
RtpHeaderExtensions session_extmaps;
cricket::SessionDescription* desc = new cricket::SessionDescription();
std::vector<JsepIceCandidate*> candidates;
size_t current_pos = 0;
bool supports_msid = false;
// Session Description
if (!ParseSessionDescription(message, &current_pos, &session_id,
&session_version, &supports_msid, &session_td,
&session_extmaps, desc, error)) {
delete desc;
return false;
}
// Media Description
if (!ParseMediaDescription(message, session_td, session_extmaps,
supports_msid, &current_pos, desc, &candidates,
error)) {
delete desc;
for (std::vector<JsepIceCandidate*>::const_iterator
it = candidates.begin(); it != candidates.end(); ++it) {
delete *it;
}
return false;
}
jdesc->Initialize(desc, session_id, session_version);
for (std::vector<JsepIceCandidate*>::const_iterator
it = candidates.begin(); it != candidates.end(); ++it) {
jdesc->AddCandidate(*it);
delete *it;
}
return true;
}
bool SdpDeserializeCandidate(const std::string& message,
JsepIceCandidate* jcandidate,
SdpParseError* error) {
ASSERT(jcandidate != NULL);
Candidate candidate;
if (!ParseCandidate(message, &candidate, error, true)) {
return false;
}
jcandidate->SetCandidate(candidate);
return true;
}
bool ParseCandidate(const std::string& message, Candidate* candidate,
SdpParseError* error, bool is_raw) {
ASSERT(candidate != NULL);
// Get the first line from |message|.
std::string first_line;
GetFirstLine(message, &first_line);
size_t start_pos = kLinePrefixLength; // Starting position to parse.
if (IsRawCandidate(first_line)) {
// From WebRTC draft section 4.8.1.1 candidate-attribute will be
// just candidate:<candidate> not a=candidate:<blah>CRLF
start_pos = 0;
} else if (!IsLineType(first_line, kLineTypeAttributes) ||
!HasAttribute(first_line, kAttributeCandidate)) {
// Must start with a=candidate line.
// Expecting to be of the format a=candidate:<blah>CRLF.
if (is_raw) {
std::ostringstream description;
description << "Expect line: "
<< kAttributeCandidate
<< ":" << "<candidate-str>";
return ParseFailed(first_line, 0, description.str(), error);
} else {
return ParseFailedExpectLine(first_line, 0, kLineTypeAttributes,
kAttributeCandidate, error);
}
}
std::vector<std::string> fields;
talk_base::split(first_line.substr(start_pos),
kSdpDelimiterSpace, &fields);
// RFC 5245
// a=candidate:<foundation> <component-id> <transport> <priority>
// <connection-address> <port> typ <candidate-types>
// [raddr <connection-address>] [rport <port>]
// *(SP extension-att-name SP extension-att-value)
const size_t expected_min_fields = 8;
if (fields.size() < expected_min_fields ||
(fields[6] != kAttributeCandidateTyp)) {
return ParseFailedExpectMinFieldNum(first_line, expected_min_fields, error);
}
std::string foundation;
if (!GetValue(fields[0], kAttributeCandidate, &foundation, error)) {
return false;
}
const int component_id = talk_base::FromString<int>(fields[1]);
const std::string transport = fields[2];
const uint32 priority = talk_base::FromString<uint32>(fields[3]);
const std::string connection_address = fields[4];
const int port = talk_base::FromString<int>(fields[5]);
SocketAddress address(connection_address, port);
cricket::ProtocolType protocol;
if (!StringToProto(transport.c_str(), &protocol)) {
return ParseFailed(first_line, "Unsupported transport type.", error);
}
std::string candidate_type;
const std::string type = fields[7];
if (type == kCandidateHost) {
candidate_type = cricket::LOCAL_PORT_TYPE;
} else if (type == kCandidateSrflx) {
candidate_type = cricket::STUN_PORT_TYPE;
} else if (type == kCandidateRelay) {
candidate_type = cricket::RELAY_PORT_TYPE;
} else {
return ParseFailed(first_line, "Unsupported candidate type.", error);
}
size_t current_position = expected_min_fields;
SocketAddress related_address;
// The 2 optional fields for related address
// [raddr <connection-address>] [rport <port>]
if (fields.size() >= (current_position + 2) &&
fields[current_position] == kAttributeCandidateRaddr) {
related_address.SetIP(fields[++current_position]);
++current_position;
}
if (fields.size() >= (current_position + 2) &&
fields[current_position] == kAttributeCandidateRport) {
related_address.SetPort(
talk_base::FromString<int>(fields[++current_position]));
++current_position;
}
// Extension
// Empty string as the candidate username and password.
// Will be updated later with the ice-ufrag and ice-pwd.
// TODO: Remove the username/password extension, which is currently
// kept for backwards compatibility.
std::string username;
std::string password;
uint32 generation = 0;
for (size_t i = current_position; i + 1 < fields.size(); ++i) {
// RFC 5245
// *(SP extension-att-name SP extension-att-value)
if (fields[i] == kAttributeCandidateGeneration) {
generation = talk_base::FromString<uint32>(fields[++i]);
} else if (fields[i] == kAttributeCandidateUsername) {
username = fields[++i];
} else if (fields[i] == kAttributeCandidatePassword) {
password = fields[++i];
} else {
// Skip the unknown extension.
++i;
}
}
// Empty string as the candidate id and network name.
const std::string id;
const std::string network_name;
*candidate = Candidate(id, component_id, cricket::ProtoToString(protocol),
address, priority, username, password, candidate_type, network_name,
generation, foundation);
candidate->set_related_address(related_address);
return true;
}
bool ParseIceOptions(const std::string& line,
std::vector<std::string>* transport_options,
SdpParseError* error) {
std::string ice_options;
if (!GetValue(line, kAttributeIceOption, &ice_options, error)) {
return false;
}
std::vector<std::string> fields;
talk_base::split(ice_options, kSdpDelimiterSpace, &fields);
for (size_t i = 0; i < fields.size(); ++i) {
transport_options->push_back(fields[i]);
}
return true;
}
bool ParseExtmap(const std::string& line, RtpHeaderExtension* extmap,
SdpParseError* error) {
// RFC 5285
// a=extmap:<value>["/"<direction>] <URI> <extensionattributes>
std::vector<std::string> fields;
talk_base::split(line.substr(kLinePrefixLength),
kSdpDelimiterSpace, &fields);
const size_t expected_min_fields = 2;
if (fields.size() < expected_min_fields) {
return ParseFailedExpectMinFieldNum(line, expected_min_fields, error);
}
std::string uri = fields[1];
std::string value_direction;
if (!GetValue(fields[0], kAttributeExtmap, &value_direction, error)) {
return false;
}
std::vector<std::string> sub_fields;
talk_base::split(value_direction, kSdpDelimiterSlash, &sub_fields);
int value = talk_base::FromString<int>(sub_fields[0]);
*extmap = RtpHeaderExtension(uri, value);
return true;
}
void BuildMediaDescription(const ContentInfo* content_info,
const TransportInfo* transport_info,
const MediaType media_type,
std::string* message) {
ASSERT(message != NULL);
if (content_info == NULL || message == NULL) {
return;
}
// TODO: Rethink if we should use sprintfn instead of stringstream.
// According to the style guide, streams should only be used for logging.
// http://google-styleguide.googlecode.com/svn/
// trunk/cppguide.xml?showone=Streams#Streams
std::ostringstream os;
const MediaContentDescription* media_desc =
static_cast<const MediaContentDescription*>(
content_info->description);
ASSERT(media_desc != NULL);
bool is_sctp = (media_desc->protocol() == cricket::kMediaProtocolDtlsSctp);
// RFC 4566
// m=<media> <port> <proto> <fmt>
// fmt is a list of payload type numbers that MAY be used in the session.
const char* type = NULL;
if (media_type == cricket::MEDIA_TYPE_AUDIO)
type = kMediaTypeAudio;
else if (media_type == cricket::MEDIA_TYPE_VIDEO)
type = kMediaTypeVideo;
else if (media_type == cricket::MEDIA_TYPE_DATA)
type = kMediaTypeData;
else
ASSERT(false);
std::string fmt;
if (media_type == cricket::MEDIA_TYPE_VIDEO) {
const VideoContentDescription* video_desc =
static_cast<const VideoContentDescription*>(media_desc);
for (std::vector<cricket::VideoCodec>::const_iterator it =
video_desc->codecs().begin();
it != video_desc->codecs().end(); ++it) {
fmt.append(" ");
fmt.append(talk_base::ToString<int>(it->id));
}
} else if (media_type == cricket::MEDIA_TYPE_AUDIO) {
const AudioContentDescription* audio_desc =
static_cast<const AudioContentDescription*>(media_desc);
for (std::vector<cricket::AudioCodec>::const_iterator it =
audio_desc->codecs().begin();
it != audio_desc->codecs().end(); ++it) {
fmt.append(" ");
fmt.append(talk_base::ToString<int>(it->id));
}
} else if (media_type == cricket::MEDIA_TYPE_DATA) {
if (is_sctp) {
fmt.append(" ");
// TODO(jiayl): Replace the hard-coded string with the fmt read out of the
// ContentDescription.
fmt.append(talk_base::ToString<int>(kDefaultSctpFmt));
} else {
const DataContentDescription* data_desc =
static_cast<const DataContentDescription*>(media_desc);
for (std::vector<cricket::DataCodec>::const_iterator it =
data_desc->codecs().begin();
it != data_desc->codecs().end(); ++it) {
fmt.append(" ");
fmt.append(talk_base::ToString<int>(it->id));
}
}
}
// The fmt must never be empty. If no codecs are found, set the fmt attribute
// to 0.
if (fmt.empty()) {
fmt = " 0";
}
// The port number in the m line will be updated later when associate with
// the candidates.
// RFC 3264
// To reject an offered stream, the port number in the corresponding stream in
// the answer MUST be set to zero.
const std::string port = content_info->rejected ?
kMediaPortRejected : kDefaultPort;
talk_base::SSLFingerprint* fp = (transport_info) ?
transport_info->description.identity_fingerprint.get() : NULL;
InitLine(kLineTypeMedia, type, &os);
os << " " << port << " " << media_desc->protocol() << fmt;
AddLine(os.str(), message);
// Use the transport_info to build the media level ice-ufrag and ice-pwd.
if (transport_info) {
// RFC 5245
// ice-pwd-att = "ice-pwd" ":" password
// ice-ufrag-att = "ice-ufrag" ":" ufrag
// ice-ufrag
InitAttrLine(kAttributeIceUfrag, &os);
os << kSdpDelimiterColon << transport_info->description.ice_ufrag;
AddLine(os.str(), message);
// ice-pwd
InitAttrLine(kAttributeIcePwd, &os);
os << kSdpDelimiterColon << transport_info->description.ice_pwd;
AddLine(os.str(), message);
// draft-petithuguenin-mmusic-ice-attributes-level-03
BuildIceOptions(transport_info->description.transport_options, message);
// RFC 4572
// fingerprint-attribute =
// "fingerprint" ":" hash-func SP fingerprint
if (fp) {
// Insert the fingerprint attribute.
InitAttrLine(kAttributeFingerprint, &os);
os << kSdpDelimiterColon
<< fp->algorithm << kSdpDelimiterSpace
<< fp->GetRfc4572Fingerprint();
AddLine(os.str(), message);
// Inserting setup attribute.
if (transport_info->description.connection_role !=
cricket::CONNECTIONROLE_NONE) {
// Making sure we are not using "passive" mode.
cricket::ConnectionRole role =
transport_info->description.connection_role;
std::string dtls_role_str;
VERIFY(cricket::ConnectionRoleToString(role, &dtls_role_str));
InitAttrLine(kAttributeSetup, &os);
os << kSdpDelimiterColon << dtls_role_str;
AddLine(os.str(), message);
}
}
}
// RFC 3388
// mid-attribute = "a=mid:" identification-tag
// identification-tag = token
// Use the content name as the mid identification-tag.
InitAttrLine(kAttributeMid, &os);
os << kSdpDelimiterColon << content_info->name;
AddLine(os.str(), message);
if (is_sctp) {
BuildSctpContentAttributes(message);
} else {
BuildRtpContentAttributes(media_desc, media_type, message);
}
}
void BuildSctpContentAttributes(std::string* message) {
// draft-ietf-mmusic-sctp-sdp-04
// a=sctpmap:sctpmap-number protocol [streams]
std::ostringstream os;
InitAttrLine(kAttributeSctpmap, &os);
os << kSdpDelimiterColon << kDefaultSctpFmt << kSdpDelimiterSpace
<< kDefaultSctpmapProtocol << kSdpDelimiterSpace
<< (cricket::kMaxSctpSid + 1);
AddLine(os.str(), message);
}
void BuildRtpContentAttributes(
const MediaContentDescription* media_desc,
const MediaType media_type,
std::string* message) {
std::ostringstream os;
// RFC 5285
// a=extmap:<value>["/"<direction>] <URI> <extensionattributes>
// The definitions MUST be either all session level or all media level. This
// implementation uses all media level.
for (size_t i = 0; i < media_desc->rtp_header_extensions().size(); ++i) {
InitAttrLine(kAttributeExtmap, &os);
os << kSdpDelimiterColon << media_desc->rtp_header_extensions()[i].id
<< kSdpDelimiterSpace << media_desc->rtp_header_extensions()[i].uri;
AddLine(os.str(), message);
}
// RFC 3264
// a=sendrecv || a=sendonly || a=sendrecv || a=inactive
cricket::MediaContentDirection direction = media_desc->direction();
if (media_desc->streams().empty() && direction == cricket::MD_SENDRECV) {
direction = cricket::MD_RECVONLY;
}
switch (direction) {
case cricket::MD_INACTIVE:
InitAttrLine(kAttributeInactive, &os);
break;
case cricket::MD_SENDONLY:
InitAttrLine(kAttributeSendOnly, &os);
break;
case cricket::MD_RECVONLY:
InitAttrLine(kAttributeRecvOnly, &os);
break;
case cricket::MD_SENDRECV:
default:
InitAttrLine(kAttributeSendRecv, &os);
break;
}
AddLine(os.str(), message);
// RFC 4566
// b=AS:<bandwidth>
// We should always use the default bandwidth for RTP-based data
// channels. Don't allow SDP to set the bandwidth, because that
// would give JS the opportunity to "break the Internet".
// TODO(pthatcher): But we need to temporarily allow the SDP to control
// this for backwards-compatibility. Once we don't need that any
// more, remove this.
bool support_dc_sdp_bandwidth_temporarily = true;
if (media_desc->bandwidth() >= 1000 &&
(media_type != cricket::MEDIA_TYPE_DATA ||
support_dc_sdp_bandwidth_temporarily)) {
InitLine(kLineTypeSessionBandwidth, kApplicationSpecificMaximum, &os);
os << kSdpDelimiterColon << (media_desc->bandwidth() / 1000);
AddLine(os.str(), message);
}
// RFC 5761
// a=rtcp-mux
if (media_desc->rtcp_mux()) {
InitAttrLine(kAttributeRtcpMux, &os);
AddLine(os.str(), message);
}
// RFC 4568
// a=crypto:<tag> <crypto-suite> <key-params> [<session-params>]
for (std::vector<CryptoParams>::const_iterator it =
media_desc->cryptos().begin();
it != media_desc->cryptos().end(); ++it) {
InitAttrLine(kAttributeCrypto, &os);
os << kSdpDelimiterColon << it->tag << " " << it->cipher_suite << " "
<< it->key_params;
if (!it->session_params.empty()) {
os << " " << it->session_params;
}
AddLine(os.str(), message);
}
// RFC 4566
// a=rtpmap:<payload type> <encoding name>/<clock rate>
// [/<encodingparameters>]
BuildRtpMap(media_desc, media_type, message);
// Specify latency for buffered mode.
// a=x-google-buffer-latency:<value>
if (media_desc->buffered_mode_latency() != cricket::kBufferedModeDisabled) {
std::ostringstream os;
InitAttrLine(kAttributeXGoogleBufferLatency, &os);
os << kSdpDelimiterColon << media_desc->buffered_mode_latency();
AddLine(os.str(), message);
}
for (StreamParamsVec::const_iterator track = media_desc->streams().begin();
track != media_desc->streams().end(); ++track) {
// Require that the track belongs to a media stream,
// ie the sync_label is set. This extra check is necessary since the
// MediaContentDescription always contains a streamparam with an ssrc even
// if no track or media stream have been created.
if (track->sync_label.empty()) continue;
// Build the ssrc-group lines.
for (size_t i = 0; i < track->ssrc_groups.size(); ++i) {
// RFC 5576
// a=ssrc-group:<semantics> <ssrc-id> ...
if (track->ssrc_groups[i].ssrcs.empty()) {
continue;
}
std::ostringstream os;
InitAttrLine(kAttributeSsrcGroup, &os);
os << kSdpDelimiterColon << track->ssrc_groups[i].semantics;
std::vector<uint32>::const_iterator ssrc =
track->ssrc_groups[i].ssrcs.begin();
for (; ssrc != track->ssrc_groups[i].ssrcs.end(); ++ssrc) {
os << kSdpDelimiterSpace << talk_base::ToString<uint32>(*ssrc);
}
AddLine(os.str(), message);
}
// Build the ssrc lines for each ssrc.
for (size_t i = 0; i < track->ssrcs.size(); ++i) {
uint32 ssrc = track->ssrcs[i];
// RFC 5576
// a=ssrc:<ssrc-id> cname:<value>
AddSsrcLine(ssrc, kSsrcAttributeCname,
track->cname, message);
// draft-alvestrand-mmusic-msid-00
// a=ssrc:<ssrc-id> msid:identifier [appdata]
// The appdata consists of the "id" attribute of a MediaStreamTrack, which
// is corresponding to the "name" attribute of StreamParams.
std::string appdata = track->id;
std::ostringstream os;
InitAttrLine(kAttributeSsrc, &os);
os << kSdpDelimiterColon << ssrc << kSdpDelimiterSpace
<< kSsrcAttributeMsid << kSdpDelimiterColon << track->sync_label
<< kSdpDelimiterSpace << appdata;
AddLine(os.str(), message);
// TODO(ronghuawu): Remove below code which is for backward compatibility.
// draft-alvestrand-rtcweb-mid-01
// a=ssrc:<ssrc-id> mslabel:<value>
// The label isn't yet defined.
// a=ssrc:<ssrc-id> label:<value>
AddSsrcLine(ssrc, kSsrcAttributeMslabel, track->sync_label, message);
AddSsrcLine(ssrc, kSSrcAttributeLabel, track->id, message);
}
}
}
void WriteFmtpHeader(int payload_type, std::ostringstream* os) {
// fmtp header: a=fmtp:|payload_type| <parameters>
// Add a=fmtp
InitAttrLine(kAttributeFmtp, os);
// Add :|payload_type|
*os << kSdpDelimiterColon << payload_type;
}
void WriteRtcpFbHeader(int payload_type, std::ostringstream* os) {
// rtcp-fb header: a=rtcp-fb:|payload_type|
// <parameters>/<ccm <ccm_parameters>>
// Add a=rtcp-fb
InitAttrLine(kAttributeRtcpFb, os);
// Add :
*os << kSdpDelimiterColon;
if (payload_type == kWildcardPayloadType) {
*os << "*";
} else {
*os << payload_type;
}
}
void WriteFmtpParameter(const std::string& parameter_name,
const std::string& parameter_value,
std::ostringstream* os) {
// fmtp parameters: |parameter_name|=|parameter_value|
*os << parameter_name << kSdpDelimiterEqual << parameter_value;
}
void WriteFmtpParameters(const cricket::CodecParameterMap& parameters,
std::ostringstream* os) {
for (cricket::CodecParameterMap::const_iterator fmtp = parameters.begin();
fmtp != parameters.end(); ++fmtp) {
// Each new parameter, except the first one starts with ";" and " ".
if (fmtp != parameters.begin()) {
*os << kSdpDelimiterSemicolon;
}
*os << kSdpDelimiterSpace;
WriteFmtpParameter(fmtp->first, fmtp->second, os);
}
}
bool IsFmtpParam(const std::string& name) {
const char* kFmtpParams[] = {
kCodecParamMinPTime, kCodecParamSPropStereo,
kCodecParamStereo, kCodecParamUseInbandFec,
kCodecParamMaxBitrate, kCodecParamMinBitrate, kCodecParamMaxQuantization,
kCodecParamSctpProtocol, kCodecParamSctpStreams,
kCodecParamMaxAverageBitrate
};
for (size_t i = 0; i < ARRAY_SIZE(kFmtpParams); ++i) {
if (_stricmp(name.c_str(), kFmtpParams[i]) == 0) {
return true;
}
}
return false;
}
// Retreives fmtp parameters from |params|, which may contain other parameters
// as well, and puts them in |fmtp_parameters|.
void GetFmtpParams(const cricket::CodecParameterMap& params,
cricket::CodecParameterMap* fmtp_parameters) {
for (cricket::CodecParameterMap::const_iterator iter = params.begin();
iter != params.end(); ++iter) {
if (IsFmtpParam(iter->first)) {
(*fmtp_parameters)[iter->first] = iter->second;
}
}
}
template <class T>
void AddFmtpLine(const T& codec, std::string* message) {
cricket::CodecParameterMap fmtp_parameters;
GetFmtpParams(codec.params, &fmtp_parameters);
if (fmtp_parameters.empty()) {
// No need to add an fmtp if it will have no (optional) parameters.
return;
}
std::ostringstream os;
WriteFmtpHeader(codec.id, &os);
WriteFmtpParameters(fmtp_parameters, &os);
AddLine(os.str(), message);
return;
}
template <class T>
void AddRtcpFbLines(const T& codec, std::string* message) {
for (std::vector<cricket::FeedbackParam>::const_iterator iter =
codec.feedback_params.params().begin();
iter != codec.feedback_params.params().end(); ++iter) {
std::ostringstream os;
WriteRtcpFbHeader(codec.id, &os);
os << " " << iter->id();
if (!iter->param().empty()) {
os << " " << iter->param();
}
AddLine(os.str(), message);
}
}
bool GetMinValue(const std::vector<int>& values, int* value) {
if (values.empty()) {
return false;
}
std::vector<int>::const_iterator found =
std::min_element(values.begin(), values.end());
*value = *found;
return true;
}
bool GetParameter(const std::string& name,
const cricket::CodecParameterMap& params, int* value) {
std::map<std::string, std::string>::const_iterator found =
params.find(name);
if (found == params.end()) {
return false;
}
*value = talk_base::FromString<int>(found->second);
return true;
}
void BuildRtpMap(const MediaContentDescription* media_desc,
const MediaType media_type,
std::string* message) {
ASSERT(message != NULL);
ASSERT(media_desc != NULL);
std::ostringstream os;
if (media_type == cricket::MEDIA_TYPE_VIDEO) {
const VideoContentDescription* video_desc =
static_cast<const VideoContentDescription*>(media_desc);
for (std::vector<cricket::VideoCodec>::const_iterator it =
video_desc->codecs().begin();
it != video_desc->codecs().end(); ++it) {
// RFC 4566
// a=rtpmap:<payload type> <encoding name>/<clock rate>
// [/<encodingparameters>]
if (it->id != kWildcardPayloadType) {
InitAttrLine(kAttributeRtpmap, &os);
os << kSdpDelimiterColon << it->id << " " << it->name
<< "/" << kDefaultVideoClockrate;
AddLine(os.str(), message);
}
AddRtcpFbLines(*it, message);
AddFmtpLine(*it, message);
}
} else if (media_type == cricket::MEDIA_TYPE_AUDIO) {
const AudioContentDescription* audio_desc =
static_cast<const AudioContentDescription*>(media_desc);
std::vector<int> ptimes;
std::vector<int> maxptimes;
int max_minptime = 0;
for (std::vector<cricket::AudioCodec>::const_iterator it =
audio_desc->codecs().begin();
it != audio_desc->codecs().end(); ++it) {
ASSERT(!it->name.empty());
// RFC 4566
// a=rtpmap:<payload type> <encoding name>/<clock rate>
// [/<encodingparameters>]
InitAttrLine(kAttributeRtpmap, &os);
os << kSdpDelimiterColon << it->id << " ";
os << it->name << "/" << it->clockrate;
if (it->channels != 1) {
os << "/" << it->channels;
}
AddLine(os.str(), message);
AddRtcpFbLines(*it, message);
AddFmtpLine(*it, message);
int minptime = 0;
if (GetParameter(kCodecParamMinPTime, it->params, &minptime)) {
max_minptime = std::max(minptime, max_minptime);
}
int ptime;
if (GetParameter(kCodecParamPTime, it->params, &ptime)) {
ptimes.push_back(ptime);
}
int maxptime;
if (GetParameter(kCodecParamMaxPTime, it->params, &maxptime)) {
maxptimes.push_back(maxptime);
}
}
// Populate the maxptime attribute with the smallest maxptime of all codecs
// under the same m-line.
int min_maxptime = INT_MAX;
if (GetMinValue(maxptimes, &min_maxptime)) {
AddAttributeLine(kCodecParamMaxPTime, min_maxptime, message);
}
ASSERT(min_maxptime > max_minptime);
// Populate the ptime attribute with the smallest ptime or the largest
// minptime, whichever is the largest, for all codecs under the same m-line.
int ptime = INT_MAX;
if (GetMinValue(ptimes, &ptime)) {
ptime = std::min(ptime, min_maxptime);
ptime = std::max(ptime, max_minptime);
AddAttributeLine(kCodecParamPTime, ptime, message);
}
} else if (media_type == cricket::MEDIA_TYPE_DATA) {
const DataContentDescription* data_desc =
static_cast<const DataContentDescription*>(media_desc);
for (std::vector<cricket::DataCodec>::const_iterator it =
data_desc->codecs().begin();
it != data_desc->codecs().end(); ++it) {
// RFC 4566
// a=rtpmap:<payload type> <encoding name>/<clock rate>
// [/<encodingparameters>]
InitAttrLine(kAttributeRtpmap, &os);
os << kSdpDelimiterColon << it->id << " "
<< it->name << "/" << it->clockrate;
AddLine(os.str(), message);
}
}
}
void BuildCandidate(const std::vector<Candidate>& candidates,
std::string* message) {
std::ostringstream os;
for (std::vector<Candidate>::const_iterator it = candidates.begin();
it != candidates.end(); ++it) {
// RFC 5245
// a=candidate:<foundation> <component-id> <transport> <priority>
// <connection-address> <port> typ <candidate-types>
// [raddr <connection-address>] [rport <port>]
// *(SP extension-att-name SP extension-att-value)
std::string type;
// Map the cricket candidate type to "host" / "srflx" / "prflx" / "relay"
if (it->type() == cricket::LOCAL_PORT_TYPE) {
type = kCandidateHost;
} else if (it->type() == cricket::STUN_PORT_TYPE) {
type = kCandidateSrflx;
} else if (it->type() == cricket::RELAY_PORT_TYPE) {
type = kCandidateRelay;
} else {
ASSERT(false);
}
InitAttrLine(kAttributeCandidate, &os);
os << kSdpDelimiterColon
<< it->foundation() << " " << it->component() << " "
<< it->protocol() << " " << it->priority() << " "
<< it->address().ipaddr().ToString() << " "
<< it->address().PortAsString() << " "
<< kAttributeCandidateTyp << " " << type << " ";
// Related address
if (!it->related_address().IsNil()) {
os << kAttributeCandidateRaddr << " "
<< it->related_address().ipaddr().ToString() << " "
<< kAttributeCandidateRport << " "
<< it->related_address().PortAsString() << " ";
}
// Extensions
os << kAttributeCandidateGeneration << " " << it->generation();
AddLine(os.str(), message);
}
}
void BuildIceOptions(const std::vector<std::string>& transport_options,
std::string* message) {
if (!transport_options.empty()) {
std::ostringstream os;
InitAttrLine(kAttributeIceOption, &os);
os << kSdpDelimiterColon << transport_options[0];
for (size_t i = 1; i < transport_options.size(); ++i) {
os << kSdpDelimiterSpace << transport_options[i];
}
AddLine(os.str(), message);
}
}
bool ParseSessionDescription(const std::string& message, size_t* pos,
std::string* session_id,
std::string* session_version,
bool* supports_msid,
TransportDescription* session_td,
RtpHeaderExtensions* session_extmaps,
cricket::SessionDescription* desc,
SdpParseError* error) {
std::string line;
// RFC 4566
// v= (protocol version)
if (!GetLineWithType(message, pos, &line, kLineTypeVersion)) {
return ParseFailedExpectLine(message, *pos, kLineTypeVersion,
std::string(), error);
}
// RFC 4566
// o=<username> <sess-id> <sess-version> <nettype> <addrtype>
// <unicast-address>
if (!GetLineWithType(message, pos, &line, kLineTypeOrigin)) {
return ParseFailedExpectLine(message, *pos, kLineTypeOrigin,
std::string(), error);
}
std::vector<std::string> fields;
talk_base::split(line.substr(kLinePrefixLength),
kSdpDelimiterSpace, &fields);
const size_t expected_fields = 6;
if (fields.size() != expected_fields) {
return ParseFailedExpectFieldNum(line, expected_fields, error);
}
*session_id = fields[1];
*session_version = fields[2];
// RFC 4566
// s= (session name)
if (!GetLineWithType(message, pos, &line, kLineTypeSessionName)) {
return ParseFailedExpectLine(message, *pos, kLineTypeSessionName,
std::string(), error);
}
// Optional lines
// Those are the optional lines, so shouldn't return false if not present.
// RFC 4566
// i=* (session information)
GetLineWithType(message, pos, &line, kLineTypeSessionInfo);
// RFC 4566
// u=* (URI of description)
GetLineWithType(message, pos, &line, kLineTypeSessionUri);
// RFC 4566
// e=* (email address)
GetLineWithType(message, pos, &line, kLineTypeSessionEmail);
// RFC 4566
// p=* (phone number)
GetLineWithType(message, pos, &line, kLineTypeSessionPhone);
// RFC 4566
// c=* (connection information -- not required if included in
// all media)
GetLineWithType(message, pos, &line, kLineTypeConnection);
// RFC 4566
// b=* (zero or more bandwidth information lines)
while (GetLineWithType(message, pos, &line, kLineTypeSessionBandwidth)) {
// By pass zero or more b lines.
}
// RFC 4566
// One or more time descriptions ("t=" and "r=" lines; see below)
// t= (time the session is active)
// r=* (zero or more repeat times)
// Ensure there's at least one time description
if (!GetLineWithType(message, pos, &line, kLineTypeTiming)) {
return ParseFailedExpectLine(message, *pos, kLineTypeTiming, std::string(),
error);
}
while (GetLineWithType(message, pos, &line, kLineTypeRepeatTimes)) {
// By pass zero or more r lines.
}
// Go through the rest of the time descriptions
while (GetLineWithType(message, pos, &line, kLineTypeTiming)) {
while (GetLineWithType(message, pos, &line, kLineTypeRepeatTimes)) {
// By pass zero or more r lines.
}
}
// RFC 4566
// z=* (time zone adjustments)
GetLineWithType(message, pos, &line, kLineTypeTimeZone);
// RFC 4566
// k=* (encryption key)
GetLineWithType(message, pos, &line, kLineTypeEncryptionKey);
// RFC 4566
// a=* (zero or more session attribute lines)
while (GetLineWithType(message, pos, &line, kLineTypeAttributes)) {
if (HasAttribute(line, kAttributeGroup)) {
if (!ParseGroupAttribute(line, desc, error)) {
return false;
}
} else if (HasAttribute(line, kAttributeIceUfrag)) {
if (!GetValue(line, kAttributeIceUfrag,
&(session_td->ice_ufrag), error)) {
return false;
}
} else if (HasAttribute(line, kAttributeIcePwd)) {
if (!GetValue(line, kAttributeIcePwd, &(session_td->ice_pwd), error)) {
return false;
}
} else if (HasAttribute(line, kAttributeIceLite)) {
session_td->ice_mode = cricket::ICEMODE_LITE;
} else if (HasAttribute(line, kAttributeIceOption)) {
if (!ParseIceOptions(line, &(session_td->transport_options), error)) {
return false;
}
} else if (HasAttribute(line, kAttributeFingerprint)) {
if (session_td->identity_fingerprint.get()) {
return ParseFailed(
line,
"Can't have multiple fingerprint attributes at the same level.",
error);
}
talk_base::SSLFingerprint* fingerprint = NULL;
if (!ParseFingerprintAttribute(line, &fingerprint, error)) {
return false;
}
session_td->identity_fingerprint.reset(fingerprint);
} else if (HasAttribute(line, kAttributeSetup)) {
if (!ParseDtlsSetup(line, &(session_td->connection_role), error)) {
return false;
}
} else if (HasAttribute(line, kAttributeMsidSemantics)) {
std::string semantics;
if (!GetValue(line, kAttributeMsidSemantics, &semantics, error)) {
return false;
}
*supports_msid = CaseInsensitiveFind(semantics, kMediaStreamSemantic);
} else if (HasAttribute(line, kAttributeExtmap)) {
RtpHeaderExtension extmap;
if (!ParseExtmap(line, &extmap, error)) {
return false;
}
session_extmaps->push_back(extmap);
}
}
return true;
}
bool ParseGroupAttribute(const std::string& line,
cricket::SessionDescription* desc,
SdpParseError* error) {
ASSERT(desc != NULL);
// RFC 5888 and draft-holmberg-mmusic-sdp-bundle-negotiation-00
// a=group:BUNDLE video voice
std::vector<std::string> fields;
talk_base::split(line.substr(kLinePrefixLength),
kSdpDelimiterSpace, &fields);
std::string semantics;
if (!GetValue(fields[0], kAttributeGroup, &semantics, error)) {
return false;
}
cricket::ContentGroup group(semantics);
for (size_t i = 1; i < fields.size(); ++i) {
group.AddContentName(fields[i]);
}
desc->AddGroup(group);
return true;
}
static bool ParseFingerprintAttribute(const std::string& line,
talk_base::SSLFingerprint** fingerprint,
SdpParseError* error) {
if (!IsLineType(line, kLineTypeAttributes) ||
!HasAttribute(line, kAttributeFingerprint)) {
return ParseFailedExpectLine(line, 0, kLineTypeAttributes,
kAttributeFingerprint, error);
}
std::vector<std::string> fields;
talk_base::split(line.substr(kLinePrefixLength),
kSdpDelimiterSpace, &fields);
const size_t expected_fields = 2;
if (fields.size() != expected_fields) {
return ParseFailedExpectFieldNum(line, expected_fields, error);
}
// The first field here is "fingerprint:<hash>.
std::string algorithm;
if (!GetValue(fields[0], kAttributeFingerprint, &algorithm, error)) {
return false;
}
// Downcase the algorithm. Note that we don't need to downcase the
// fingerprint because hex_decode can handle upper-case.
std::transform(algorithm.begin(), algorithm.end(), algorithm.begin(),
::tolower);
// The second field is the digest value. De-hexify it.
*fingerprint = talk_base::SSLFingerprint::CreateFromRfc4572(
algorithm, fields[1]);
if (!*fingerprint) {
return ParseFailed(line,
"Failed to create fingerprint from the digest.",
error);
}
return true;
}
static bool ParseDtlsSetup(const std::string& line,
cricket::ConnectionRole* role,
SdpParseError* error) {
// setup-attr = "a=setup:" role
// role = "active" / "passive" / "actpass" / "holdconn"
std::vector<std::string> fields;
talk_base::split(line.substr(kLinePrefixLength), kSdpDelimiterColon, &fields);
const size_t expected_fields = 2;
if (fields.size() != expected_fields) {
return ParseFailedExpectFieldNum(line, expected_fields, error);
}
std::string role_str = fields[1];
if (!cricket::StringToConnectionRole(role_str, role)) {
return ParseFailed(line, "Invalid attribute value.", error);
}
return true;
}
// RFC 3551
// PT encoding media type clock rate channels
// name (Hz)
// 0 PCMU A 8,000 1
// 1 reserved A
// 2 reserved A
// 3 GSM A 8,000 1
// 4 G723 A 8,000 1
// 5 DVI4 A 8,000 1
// 6 DVI4 A 16,000 1
// 7 LPC A 8,000 1
// 8 PCMA A 8,000 1
// 9 G722 A 8,000 1
// 10 L16 A 44,100 2
// 11 L16 A 44,100 1
// 12 QCELP A 8,000 1
// 13 CN A 8,000 1
// 14 MPA A 90,000 (see text)
// 15 G728 A 8,000 1
// 16 DVI4 A 11,025 1
// 17 DVI4 A 22,050 1
// 18 G729 A 8,000 1
struct StaticPayloadAudioCodec {
const char* name;
int clockrate;
int channels;
};
static const StaticPayloadAudioCodec kStaticPayloadAudioCodecs[] = {
{ "PCMU", 8000, 1 },
{ "reserved", 0, 0 },
{ "reserved", 0, 0 },
{ "GSM", 8000, 1 },
{ "G723", 8000, 1 },
{ "DVI4", 8000, 1 },
{ "DVI4", 16000, 1 },
{ "LPC", 8000, 1 },
{ "PCMA", 8000, 1 },
{ "G722", 8000, 1 },
{ "L16", 44100, 2 },
{ "L16", 44100, 1 },
{ "QCELP", 8000, 1 },
{ "CN", 8000, 1 },
{ "MPA", 90000, 1 },
{ "G728", 8000, 1 },
{ "DVI4", 11025, 1 },
{ "DVI4", 22050, 1 },
{ "G729", 8000, 1 },
};
void MaybeCreateStaticPayloadAudioCodecs(
const std::vector<int>& fmts, AudioContentDescription* media_desc) {
if (!media_desc) {
return;
}
int preference = static_cast<int>(fmts.size());
std::vector<int>::const_iterator it = fmts.begin();
bool add_new_codec = false;
for (; it != fmts.end(); ++it) {
int payload_type = *it;
if (!media_desc->HasCodec(payload_type) &&
payload_type >= 0 &&
payload_type < ARRAY_SIZE(kStaticPayloadAudioCodecs)) {
std::string encoding_name = kStaticPayloadAudioCodecs[payload_type].name;
int clock_rate = kStaticPayloadAudioCodecs[payload_type].clockrate;
int channels = kStaticPayloadAudioCodecs[payload_type].channels;
media_desc->AddCodec(cricket::AudioCodec(payload_type, encoding_name,
clock_rate, 0, channels,
preference));
add_new_codec = true;
}
--preference;
}
if (add_new_codec) {
media_desc->SortCodecs();
}
}
template <class C>
static C* ParseContentDescription(const std::string& message,
const MediaType media_type,
int mline_index,
const std::string& protocol,
const std::vector<int>& codec_preference,
size_t* pos,
std::string* content_name,
TransportDescription* transport,
std::vector<JsepIceCandidate*>* candidates,
webrtc::SdpParseError* error) {
C* media_desc = new C();
switch (media_type) {
case cricket::MEDIA_TYPE_AUDIO:
*content_name = cricket::CN_AUDIO;
break;
case cricket::MEDIA_TYPE_VIDEO:
*content_name = cricket::CN_VIDEO;
break;
case cricket::MEDIA_TYPE_DATA:
*content_name = cricket::CN_DATA;
break;
default:
ASSERT(false);
break;
}
if (!ParseContent(message, media_type, mline_index, protocol,
codec_preference, pos, content_name,
media_desc, transport, candidates, error)) {
delete media_desc;
return NULL;
}
// Sort the codecs according to the m-line fmt list.
media_desc->SortCodecs();
return media_desc;
}
bool ParseMediaDescription(const std::string& message,
const TransportDescription& session_td,
const RtpHeaderExtensions& session_extmaps,
bool supports_msid,
size_t* pos,
cricket::SessionDescription* desc,
std::vector<JsepIceCandidate*>* candidates,
SdpParseError* error) {
ASSERT(desc != NULL);
std::string line;
int mline_index = -1;
// Zero or more media descriptions
// RFC 4566
// m=<media> <port> <proto> <fmt>
while (GetLineWithType(message, pos, &line, kLineTypeMedia)) {
++mline_index;
std::vector<std::string> fields;
talk_base::split(line.substr(kLinePrefixLength),
kSdpDelimiterSpace, &fields);
const size_t expected_min_fields = 4;
if (fields.size() < expected_min_fields) {
return ParseFailedExpectMinFieldNum(line, expected_min_fields, error);
}
bool rejected = false;
// RFC 3264
// To reject an offered stream, the port number in the corresponding stream
// in the answer MUST be set to zero.
if (fields[1] == kMediaPortRejected) {
rejected = true;
}
std::string protocol = fields[2];
bool is_sctp = (protocol == cricket::kMediaProtocolDtlsSctp);
// <fmt>
std::vector<int> codec_preference;
for (size_t j = 3 ; j < fields.size(); ++j) {
codec_preference.push_back(talk_base::FromString<int>(fields[j]));
}
// Make a temporary TransportDescription based on |session_td|.
// Some of this gets overwritten by ParseContent.
TransportDescription transport(NS_JINGLE_ICE_UDP,
session_td.transport_options,
session_td.ice_ufrag,
session_td.ice_pwd,
session_td.ice_mode,
session_td.connection_role,
session_td.identity_fingerprint.get(),
Candidates());
talk_base::scoped_ptr<MediaContentDescription> content;
std::string content_name;
if (HasAttribute(line, kMediaTypeVideo)) {
content.reset(ParseContentDescription<VideoContentDescription>(
message, cricket::MEDIA_TYPE_VIDEO, mline_index, protocol,
codec_preference, pos, &content_name,
&transport, candidates, error));
} else if (HasAttribute(line, kMediaTypeAudio)) {
content.reset(ParseContentDescription<AudioContentDescription>(
message, cricket::MEDIA_TYPE_AUDIO, mline_index, protocol,
codec_preference, pos, &content_name,
&transport, candidates, error));
MaybeCreateStaticPayloadAudioCodecs(
codec_preference,
static_cast<AudioContentDescription*>(content.get()));
} else if (HasAttribute(line, kMediaTypeData)) {
DataContentDescription* desc =
ParseContentDescription<DataContentDescription>(
message, cricket::MEDIA_TYPE_DATA, mline_index, protocol,
codec_preference, pos, &content_name,
&transport, candidates, error);
if (protocol == cricket::kMediaProtocolDtlsSctp) {
// Add the SCTP Port number as a pseudo-codec "port" parameter
cricket::DataCodec codec_port(
cricket::kGoogleSctpDataCodecId, cricket::kGoogleSctpDataCodecName,
0);
codec_port.SetParam(cricket::kCodecParamPort, fields[3]);
LOG(INFO) << "ParseMediaDescription: Got SCTP Port Number "
<< fields[3];
desc->AddCodec(codec_port);
}
content.reset(desc);
// We should always use the default bandwidth for RTP-based data
// channels. Don't allow SDP to set the bandwidth, because that
// would give JS the opportunity to "break the Internet".
// TODO(pthatcher): But we need to temporarily allow the SDP to control
// this for backwards-compatibility. Once we don't need that any
// more, remove this.
bool support_dc_sdp_bandwidth_temporarily = true;
if (content.get() && !support_dc_sdp_bandwidth_temporarily) {
content->set_bandwidth(cricket::kAutoBandwidth);
}
} else {
LOG(LS_WARNING) << "Unsupported media type: " << line;
continue;
}
if (!content.get()) {
// ParseContentDescription returns NULL if failed.
return false;
}
if (!is_sctp) {
// Make sure to set the media direction correctly. If the direction is not
// MD_RECVONLY or Inactive and no streams are parsed,
// a default MediaStream will be created to prepare for receiving media.
if (supports_msid && content->streams().empty() &&
content->direction() == cricket::MD_SENDRECV) {
content->set_direction(cricket::MD_RECVONLY);
}
// Set the extmap.
if (!session_extmaps.empty() &&
!content->rtp_header_extensions().empty()) {
return ParseFailed("",
"The a=extmap MUST be either all session level or "
"all media level.",
error);
}
for (size_t i = 0; i < session_extmaps.size(); ++i) {
content->AddRtpHeaderExtension(session_extmaps[i]);
}
}
content->set_protocol(protocol);
desc->AddContent(content_name,
is_sctp ? cricket::NS_JINGLE_DRAFT_SCTP :
cricket::NS_JINGLE_RTP,
rejected,
content.release());
// Create TransportInfo with the media level "ice-pwd" and "ice-ufrag".
TransportInfo transport_info(content_name, transport);
if (!desc->AddTransportInfo(transport_info)) {
std::ostringstream description;
description << "Failed to AddTransportInfo with content name: "
<< content_name;
return ParseFailed("", description.str(), error);
}
}
return true;
}
bool VerifyCodec(const cricket::Codec& codec) {
// Codec has not been populated correctly unless the name has been set. This
// can happen if an SDP has an fmtp or rtcp-fb with a payload type but doesn't
// have a corresponding "rtpmap" line.
cricket::Codec default_codec;
return default_codec.name != codec.name;
}
bool VerifyAudioCodecs(const AudioContentDescription* audio_desc) {
const std::vector<cricket::AudioCodec>& codecs = audio_desc->codecs();
for (std::vector<cricket::AudioCodec>::const_iterator iter = codecs.begin();
iter != codecs.end(); ++iter) {
if (!VerifyCodec(*iter)) {
return false;
}
}
return true;
}
bool VerifyVideoCodecs(const VideoContentDescription* video_desc) {
const std::vector<cricket::VideoCodec>& codecs = video_desc->codecs();
for (std::vector<cricket::VideoCodec>::const_iterator iter = codecs.begin();
iter != codecs.end(); ++iter) {
if (!VerifyCodec(*iter)) {
return false;
}
}
return true;
}
void AddParameters(const cricket::CodecParameterMap& parameters,
cricket::Codec* codec) {
for (cricket::CodecParameterMap::const_iterator iter =
parameters.begin(); iter != parameters.end(); ++iter) {
codec->SetParam(iter->first, iter->second);
}
}
void AddFeedbackParameter(const cricket::FeedbackParam& feedback_param,
cricket::Codec* codec) {
codec->AddFeedbackParam(feedback_param);
}
void AddFeedbackParameters(const cricket::FeedbackParams& feedback_params,
cricket::Codec* codec) {
for (std::vector<cricket::FeedbackParam>::const_iterator iter =
feedback_params.params().begin();
iter != feedback_params.params().end(); ++iter) {
codec->AddFeedbackParam(*iter);
}
}
// Gets the current codec setting associated with |payload_type|. If there
// is no AudioCodec associated with that payload type it returns an empty codec
// with that payload type.
template <class T>
T GetCodec(const std::vector<T>& codecs, int payload_type) {
for (typename std::vector<T>::const_iterator codec = codecs.begin();
codec != codecs.end(); ++codec) {
if (codec->id == payload_type) {
return *codec;
}
}
T ret_val = T();
ret_val.id = payload_type;
return ret_val;
}
// Updates or creates a new codec entry in the audio description.
template <class T, class U>
void AddOrReplaceCodec(MediaContentDescription* content_desc, const U& codec) {
T* desc = static_cast<T*>(content_desc);
std::vector<U> codecs = desc->codecs();
bool found = false;
typename std::vector<U>::iterator iter;
for (iter = codecs.begin(); iter != codecs.end(); ++iter) {
if (iter->id == codec.id) {
*iter = codec;
found = true;
break;
}
}
if (!found) {
desc->AddCodec(codec);
return;
}
desc->set_codecs(codecs);
}
// Adds or updates existing codec corresponding to |payload_type| according
// to |parameters|.
template <class T, class U>
void UpdateCodec(MediaContentDescription* content_desc, int payload_type,
const cricket::CodecParameterMap& parameters) {
// Codec might already have been populated (from rtpmap).
U new_codec = GetCodec(static_cast<T*>(content_desc)->codecs(), payload_type);
AddParameters(parameters, &new_codec);
AddOrReplaceCodec<T, U>(content_desc, new_codec);
}
// Adds or updates existing codec corresponding to |payload_type| according
// to |feedback_param|.
template <class T, class U>
void UpdateCodec(MediaContentDescription* content_desc, int payload_type,
const cricket::FeedbackParam& feedback_param) {
// Codec might already have been populated (from rtpmap).
U new_codec = GetCodec(static_cast<T*>(content_desc)->codecs(), payload_type);
AddFeedbackParameter(feedback_param, &new_codec);
AddOrReplaceCodec<T, U>(content_desc, new_codec);
}
bool PopWildcardCodec(std::vector<cricket::VideoCodec>* codecs,
cricket::VideoCodec* wildcard_codec) {
for (std::vector<cricket::VideoCodec>::iterator iter = codecs->begin();
iter != codecs->end(); ++iter) {
if (iter->id == kWildcardPayloadType) {
*wildcard_codec = *iter;
codecs->erase(iter);
return true;
}
}
return false;
}
void UpdateFromWildcardVideoCodecs(VideoContentDescription* video_desc) {
std::vector<cricket::VideoCodec> codecs = video_desc->codecs();
cricket::VideoCodec wildcard_codec;
if (!PopWildcardCodec(&codecs, &wildcard_codec)) {
return;
}
for (std::vector<cricket::VideoCodec>::iterator iter = codecs.begin();
iter != codecs.end(); ++iter) {
cricket::VideoCodec& codec = *iter;
AddFeedbackParameters(wildcard_codec.feedback_params, &codec);
}
video_desc->set_codecs(codecs);
}
void AddAudioAttribute(const std::string& name, const std::string& value,
AudioContentDescription* audio_desc) {
if (value.empty()) {
return;
}
std::vector<cricket::AudioCodec> codecs = audio_desc->codecs();
for (std::vector<cricket::AudioCodec>::iterator iter = codecs.begin();
iter != codecs.end(); ++iter) {
iter->params[name] = value;
}
audio_desc->set_codecs(codecs);
}
bool ParseContent(const std::string& message,
const MediaType media_type,
int mline_index,
const std::string& protocol,
const std::vector<int>& codec_preference,
size_t* pos,
std::string* content_name,
MediaContentDescription* media_desc,
TransportDescription* transport,
std::vector<JsepIceCandidate*>* candidates,
SdpParseError* error) {
ASSERT(media_desc != NULL);
ASSERT(content_name != NULL);
ASSERT(transport != NULL);
// The media level "ice-ufrag" and "ice-pwd".
// The candidates before update the media level "ice-pwd" and "ice-ufrag".
Candidates candidates_orig;
std::string line;
std::string mline_id;
// Tracks created out of the ssrc attributes.
StreamParamsVec tracks;
SsrcInfoVec ssrc_infos;
SsrcGroupVec ssrc_groups;
std::string maxptime_as_string;
std::string ptime_as_string;
bool is_rtp =
protocol.empty() ||
talk_base::starts_with(protocol.data(),
cricket::kMediaProtocolRtpPrefix);
// Loop until the next m line
while (!IsLineType(message, kLineTypeMedia, *pos)) {
if (!GetLine(message, pos, &line)) {
if (*pos >= message.size()) {
break; // Done parsing
} else {
return ParseFailed(message, *pos, "Can't find valid SDP line.", error);
}
}
if (IsLineType(line, kLineTypeSessionBandwidth)) {
std::string bandwidth;
if (HasAttribute(line, kApplicationSpecificMaximum)) {
if (!GetValue(line, kApplicationSpecificMaximum, &bandwidth, error)) {
return false;
} else {
media_desc->set_bandwidth(
talk_base::FromString<int>(bandwidth) * 1000);
}
}
continue;
}
// RFC 4566
// b=* (zero or more bandwidth information lines)
if (IsLineType(line, kLineTypeSessionBandwidth)) {
std::string bandwidth;
if (HasAttribute(line, kApplicationSpecificMaximum)) {
if (!GetValue(line, kApplicationSpecificMaximum, &bandwidth, error)) {
return false;
} else {
media_desc->set_bandwidth(
talk_base::FromString<int>(bandwidth) * 1000);
}
}
continue;
}
if (!IsLineType(line, kLineTypeAttributes)) {
// TODO: Handle other lines if needed.
LOG(LS_INFO) << "Ignored line: " << line;
continue;
}
// Handle attributes common to SCTP and RTP.
if (HasAttribute(line, kAttributeMid)) {
// RFC 3388
// mid-attribute = "a=mid:" identification-tag
// identification-tag = token
// Use the mid identification-tag as the content name.
if (!GetValue(line, kAttributeMid, &mline_id, error)) {
return false;
}
*content_name = mline_id;
} else if (HasAttribute(line, kAttributeCandidate)) {
Candidate candidate;
if (!ParseCandidate(line, &candidate, error, false)) {
return false;
}
candidates_orig.push_back(candidate);
} else if (HasAttribute(line, kAttributeIceUfrag)) {
if (!GetValue(line, kAttributeIceUfrag, &transport->ice_ufrag, error)) {
return false;
}
} else if (HasAttribute(line, kAttributeIcePwd)) {
if (!GetValue(line, kAttributeIcePwd, &transport->ice_pwd, error)) {
return false;
}
} else if (HasAttribute(line, kAttributeIceOption)) {
if (!ParseIceOptions(line, &transport->transport_options, error)) {
return false;
}
} else if (HasAttribute(line, kAttributeFmtp)) {
if (!ParseFmtpAttributes(line, media_type, media_desc, error)) {
return false;
}
} else if (HasAttribute(line, kAttributeFingerprint)) {
talk_base::SSLFingerprint* fingerprint = NULL;
if (!ParseFingerprintAttribute(line, &fingerprint, error)) {
return false;
}
transport->identity_fingerprint.reset(fingerprint);
} else if (HasAttribute(line, kAttributeSetup)) {
if (!ParseDtlsSetup(line, &(transport->connection_role), error)) {
return false;
}
} else if (is_rtp) {
//
// RTP specific attrubtes
//
if (HasAttribute(line, kAttributeRtcpMux)) {
media_desc->set_rtcp_mux(true);
} else if (HasAttribute(line, kAttributeSsrcGroup)) {
if (!ParseSsrcGroupAttribute(line, &ssrc_groups, error)) {
return false;
}
} else if (HasAttribute(line, kAttributeSsrc)) {
if (!ParseSsrcAttribute(line, &ssrc_infos, error)) {
return false;
}
} else if (HasAttribute(line, kAttributeCrypto)) {
if (!ParseCryptoAttribute(line, media_desc, error)) {
return false;
}
} else if (HasAttribute(line, kAttributeRtpmap)) {
if (!ParseRtpmapAttribute(line, media_type, codec_preference,
media_desc, error)) {
return false;
}
} else if (HasAttribute(line, kCodecParamMaxPTime)) {
if (!GetValue(line, kCodecParamMaxPTime, &maxptime_as_string, error)) {
return false;
}
} else if (HasAttribute(line, kAttributeRtcpFb)) {
if (!ParseRtcpFbAttribute(line, media_type, media_desc, error)) {
return false;
}
} else if (HasAttribute(line, kCodecParamPTime)) {
if (!GetValue(line, kCodecParamPTime, &ptime_as_string, error)) {
return false;
}
} else if (HasAttribute(line, kAttributeSendOnly)) {
media_desc->set_direction(cricket::MD_SENDONLY);
} else if (HasAttribute(line, kAttributeRecvOnly)) {
media_desc->set_direction(cricket::MD_RECVONLY);
} else if (HasAttribute(line, kAttributeInactive)) {
media_desc->set_direction(cricket::MD_INACTIVE);
} else if (HasAttribute(line, kAttributeSendRecv)) {
media_desc->set_direction(cricket::MD_SENDRECV);
} else if (HasAttribute(line, kAttributeExtmap)) {
RtpHeaderExtension extmap;
if (!ParseExtmap(line, &extmap, error)) {
return false;
}
media_desc->AddRtpHeaderExtension(extmap);
} else if (HasAttribute(line, kAttributeXGoogleFlag)) {
// Experimental attribute. Conference mode activates more aggressive
// AEC and NS settings.
// TODO: expose API to set these directly.
std::string flag_value;
if (!GetValue(line, kAttributeXGoogleFlag, &flag_value, error)) {
return false;
}
if (flag_value.compare(kValueConference) == 0)
media_desc->set_conference_mode(true);
} else if (HasAttribute(line, kAttributeXGoogleBufferLatency)) {
// Experimental attribute.
// TODO: expose API to set this directly.
std::string flag_value;
if (!GetValue(line, kAttributeXGoogleBufferLatency, &flag_value,
error)) {
return false;
}
int buffer_latency = 0;
if (!talk_base::FromString(flag_value, &buffer_latency) ||
buffer_latency < 0) {
return ParseFailed(message, "Invalid buffer latency.", error);
}
media_desc->set_buffered_mode_latency(buffer_latency);
}
} else {
// Only parse lines that we are interested of.
LOG(LS_INFO) << "Ignored line: " << line;
continue;
}
}
// Create tracks from the |ssrc_infos|.
CreateTracksFromSsrcInfos(ssrc_infos, &tracks);
// Add the ssrc group to the track.
for (SsrcGroupVec::iterator ssrc_group = ssrc_groups.begin();
ssrc_group != ssrc_groups.end(); ++ssrc_group) {
if (ssrc_group->ssrcs.empty()) {
continue;
}
uint32 ssrc = ssrc_group->ssrcs.front();
for (StreamParamsVec::iterator track = tracks.begin();
track != tracks.end(); ++track) {
if (track->has_ssrc(ssrc)) {
track->ssrc_groups.push_back(*ssrc_group);
}
}
}
// Add the new tracks to the |media_desc|.
for (StreamParamsVec::iterator track = tracks.begin();
track != tracks.end(); ++track) {
media_desc->AddStream(*track);
}
if (media_type == cricket::MEDIA_TYPE_AUDIO) {
AudioContentDescription* audio_desc =
static_cast<AudioContentDescription*>(media_desc);
// Verify audio codec ensures that no audio codec has been populated with
// only fmtp.
if (!VerifyAudioCodecs(audio_desc)) {
return ParseFailed("Failed to parse audio codecs correctly.", error);
}
AddAudioAttribute(kCodecParamMaxPTime, maxptime_as_string, audio_desc);
AddAudioAttribute(kCodecParamPTime, ptime_as_string, audio_desc);
}
if (media_type == cricket::MEDIA_TYPE_VIDEO) {
VideoContentDescription* video_desc =
static_cast<VideoContentDescription*>(media_desc);
UpdateFromWildcardVideoCodecs(video_desc);
// Verify video codec ensures that no video codec has been populated with
// only rtcp-fb.
if (!VerifyVideoCodecs(video_desc)) {
return ParseFailed("Failed to parse video codecs correctly.", error);
}
}
// RFC 5245
// Update the candidates with the media level "ice-pwd" and "ice-ufrag".
for (Candidates::iterator it = candidates_orig.begin();
it != candidates_orig.end(); ++it) {
ASSERT((*it).username().empty());
(*it).set_username(transport->ice_ufrag);
ASSERT((*it).password().empty());
(*it).set_password(transport->ice_pwd);
candidates->push_back(
new JsepIceCandidate(mline_id, mline_index, *it));
}
return true;
}
bool ParseSsrcAttribute(const std::string& line, SsrcInfoVec* ssrc_infos,
SdpParseError* error) {
ASSERT(ssrc_infos != NULL);
// RFC 5576
// a=ssrc:<ssrc-id> <attribute>
// a=ssrc:<ssrc-id> <attribute>:<value>
std::string field1, field2;
if (!SplitByDelimiter(line.substr(kLinePrefixLength),
kSdpDelimiterSpace,
&field1,
&field2)) {
const size_t expected_fields = 2;
return ParseFailedExpectFieldNum(line, expected_fields, error);
}
// ssrc:<ssrc-id>
std::string ssrc_id_s;
if (!GetValue(field1, kAttributeSsrc, &ssrc_id_s, error)) {
return false;
}
uint32 ssrc_id = talk_base::FromString<uint32>(ssrc_id_s);
std::string attribute;
std::string value;
if (!SplitByDelimiter(field2, kSdpDelimiterColon,
&attribute, &value)) {
std::ostringstream description;
description << "Failed to get the ssrc attribute value from " << field2
<< ". Expected format <attribute>:<value>.";
return ParseFailed(line, description.str(), error);
}
// Check if there's already an item for this |ssrc_id|. Create a new one if
// there isn't.
SsrcInfoVec::iterator ssrc_info = ssrc_infos->begin();
for (; ssrc_info != ssrc_infos->end(); ++ssrc_info) {
if (ssrc_info->ssrc_id == ssrc_id) {
break;
}
}
if (ssrc_info == ssrc_infos->end()) {
SsrcInfo info;
info.ssrc_id = ssrc_id;
ssrc_infos->push_back(info);
ssrc_info = ssrc_infos->end() - 1;
}
// Store the info to the |ssrc_info|.
if (attribute == kSsrcAttributeCname) {
// RFC 5576
// cname:<value>
ssrc_info->cname = value;
} else if (attribute == kSsrcAttributeMsid) {
// draft-alvestrand-mmusic-msid-00
// "msid:" identifier [ " " appdata ]
std::vector<std::string> fields;
talk_base::split(value, kSdpDelimiterSpace, &fields);
if (fields.size() < 1 || fields.size() > 2) {
return ParseFailed(line,
"Expected format \"msid:<identifier>[ <appdata>]\".",
error);
}
ssrc_info->msid_identifier = fields[0];
if (fields.size() == 2) {
ssrc_info->msid_appdata = fields[1];
}
} else if (attribute == kSsrcAttributeMslabel) {
// draft-alvestrand-rtcweb-mid-01
// mslabel:<value>
ssrc_info->mslabel = value;
} else if (attribute == kSSrcAttributeLabel) {
// The label isn't defined.
// label:<value>
ssrc_info->label = value;
}
return true;
}
bool ParseSsrcGroupAttribute(const std::string& line,
SsrcGroupVec* ssrc_groups,
SdpParseError* error) {
ASSERT(ssrc_groups != NULL);
// RFC 5576
// a=ssrc-group:<semantics> <ssrc-id> ...
std::vector<std::string> fields;
talk_base::split(line.substr(kLinePrefixLength),
kSdpDelimiterSpace, &fields);
const size_t expected_min_fields = 2;
if (fields.size() < expected_min_fields) {
return ParseFailedExpectMinFieldNum(line, expected_min_fields, error);
}
std::string semantics;
if (!GetValue(fields[0], kAttributeSsrcGroup, &semantics, error)) {
return false;
}
std::vector<uint32> ssrcs;
for (size_t i = 1; i < fields.size(); ++i) {
uint32 ssrc = talk_base::FromString<uint32>(fields[i]);
ssrcs.push_back(ssrc);
}
ssrc_groups->push_back(SsrcGroup(semantics, ssrcs));
return true;
}
bool ParseCryptoAttribute(const std::string& line,
MediaContentDescription* media_desc,
SdpParseError* error) {
std::vector<std::string> fields;
talk_base::split(line.substr(kLinePrefixLength),
kSdpDelimiterSpace, &fields);
// RFC 4568
// a=crypto:<tag> <crypto-suite> <key-params> [<session-params>]
const size_t expected_min_fields = 3;
if (fields.size() < expected_min_fields) {
return ParseFailedExpectMinFieldNum(line, expected_min_fields, error);
}
std::string tag_value;
if (!GetValue(fields[0], kAttributeCrypto, &tag_value, error)) {
return false;
}
int tag = talk_base::FromString<int>(tag_value);
const std::string crypto_suite = fields[1];
const std::string key_params = fields[2];
std::string session_params;
if (fields.size() > 3) {
session_params = fields[3];
}
media_desc->AddCrypto(CryptoParams(tag, crypto_suite, key_params,
session_params));
return true;
}
// Updates or creates a new codec entry in the audio description with according
// to |name|, |clockrate|, |bitrate|, |channels| and |preference|.
void UpdateCodec(int payload_type, const std::string& name, int clockrate,
int bitrate, int channels, int preference,
AudioContentDescription* audio_desc) {
// Codec may already be populated with (only) optional parameters
// (from an fmtp).
cricket::AudioCodec codec = GetCodec(audio_desc->codecs(), payload_type);
codec.name = name;
codec.clockrate = clockrate;
codec.bitrate = bitrate;
codec.channels = channels;
codec.preference = preference;
AddOrReplaceCodec<AudioContentDescription, cricket::AudioCodec>(audio_desc,
codec);
}
// Updates or creates a new codec entry in the video description according to
// |name|, |width|, |height|, |framerate| and |preference|.
void UpdateCodec(int payload_type, const std::string& name, int width,
int height, int framerate, int preference,
VideoContentDescription* video_desc) {
// Codec may already be populated with (only) optional parameters
// (from an fmtp).
cricket::VideoCodec codec = GetCodec(video_desc->codecs(), payload_type);
codec.name = name;
codec.width = width;
codec.height = height;
codec.framerate = framerate;
codec.preference = preference;
AddOrReplaceCodec<VideoContentDescription, cricket::VideoCodec>(video_desc,
codec);
}
bool ParseRtpmapAttribute(const std::string& line,
const MediaType media_type,
const std::vector<int>& codec_preference,
MediaContentDescription* media_desc,
SdpParseError* error) {
std::vector<std::string> fields;
talk_base::split(line.substr(kLinePrefixLength),
kSdpDelimiterSpace, &fields);
// RFC 4566
// a=rtpmap:<payload type> <encoding name>/<clock rate>[/<encodingparameters>]
const size_t expected_min_fields = 2;
if (fields.size() < expected_min_fields) {
return ParseFailedExpectMinFieldNum(line, expected_min_fields, error);
}
std::string payload_type_value;
if (!GetValue(fields[0], kAttributeRtpmap, &payload_type_value, error)) {
return false;
}
const int payload_type = talk_base::FromString<int>(payload_type_value);
// Set the preference order depending on the order of the pl type in the
// <fmt> of the m-line.
const int preference = codec_preference.end() -
std::find(codec_preference.begin(), codec_preference.end(),
payload_type);
if (preference == 0) {
LOG(LS_WARNING) << "Ignore rtpmap line that did not appear in the "
<< "<fmt> of the m-line: " << line;
return true;
}
const std::string encoder = fields[1];
std::vector<std::string> codec_params;
talk_base::split(encoder, '/', &codec_params);
// <encoding name>/<clock rate>[/<encodingparameters>]
// 2 mandatory fields
if (codec_params.size() < 2 || codec_params.size() > 3) {
return ParseFailed(line,
"Expected format \"<encoding name>/<clock rate>"
"[/<encodingparameters>]\".",
error);
}
const std::string encoding_name = codec_params[0];
const int clock_rate = talk_base::FromString<int>(codec_params[1]);
if (media_type == cricket::MEDIA_TYPE_VIDEO) {
VideoContentDescription* video_desc =
static_cast<VideoContentDescription*>(media_desc);
// TODO: We will send resolution in SDP. For now use
// JsepSessionDescription::kMaxVideoCodecWidth and kMaxVideoCodecHeight.
UpdateCodec(payload_type, encoding_name,
JsepSessionDescription::kMaxVideoCodecWidth,
JsepSessionDescription::kMaxVideoCodecHeight,
JsepSessionDescription::kDefaultVideoCodecFramerate,
preference, video_desc);
} else if (media_type == cricket::MEDIA_TYPE_AUDIO) {
// RFC 4566
// For audio streams, <encoding parameters> indicates the number
// of audio channels. This parameter is OPTIONAL and may be
// omitted if the number of channels is one, provided that no
// additional parameters are needed.
int channels = 1;
if (codec_params.size() == 3) {
channels = talk_base::FromString<int>(codec_params[2]);
}
int bitrate = 0;
// The default behavior for ISAC (bitrate == 0) in webrtcvoiceengine.cc
// (specifically FindWebRtcCodec) is bandwidth-adaptive variable bitrate.
// The bandwidth adaptation doesn't always work well, so this code
// sets a fixed target bitrate instead.
if (_stricmp(encoding_name.c_str(), kIsacCodecName) == 0) {
if (clock_rate <= 16000) {
bitrate = kIsacWbDefaultRate;
} else {
bitrate = kIsacSwbDefaultRate;
}
}
AudioContentDescription* audio_desc =
static_cast<AudioContentDescription*>(media_desc);
UpdateCodec(payload_type, encoding_name, clock_rate, bitrate, channels,
preference, audio_desc);
} else if (media_type == cricket::MEDIA_TYPE_DATA) {
DataContentDescription* data_desc =
static_cast<DataContentDescription*>(media_desc);
data_desc->AddCodec(cricket::DataCodec(payload_type, encoding_name,
preference));
}
return true;
}
void PruneRight(const char delimiter, std::string* message) {
size_t trailing = message->find(delimiter);
if (trailing != std::string::npos) {
*message = message->substr(0, trailing);
}
}
bool ParseFmtpParam(const std::string& line, std::string* parameter,
std::string* value, SdpParseError* error) {
if (!SplitByDelimiter(line, kSdpDelimiterEqual, parameter, value)) {
ParseFailed(line, "Unable to parse fmtp parameter. \'=\' missing.", error);
return false;
}
// a=fmtp:<payload_type> <param1>=<value1>; <param2>=<value2>; ...
// When parsing the values the trailing ";" gets picked up. Remove them.
PruneRight(kSdpDelimiterSemicolon, value);
return true;
}
bool ParseFmtpAttributes(const std::string& line, const MediaType media_type,
MediaContentDescription* media_desc,
SdpParseError* error) {
if (media_type != cricket::MEDIA_TYPE_AUDIO &&
media_type != cricket::MEDIA_TYPE_VIDEO) {
return true;
}
std::vector<std::string> fields;
talk_base::split(line.substr(kLinePrefixLength),
kSdpDelimiterSpace, &fields);
// RFC 5576
// a=fmtp:<format> <format specific parameters>
// At least two fields, whereas the second one is any of the optional
// parameters.
if (fields.size() < 2) {
ParseFailedExpectMinFieldNum(line, 2, error);
return false;
}
std::string payload_type;
if (!GetValue(fields[0], kAttributeFmtp, &payload_type, error)) {
return false;
}
cricket::CodecParameterMap codec_params;
for (std::vector<std::string>::const_iterator iter = fields.begin() + 1;
iter != fields.end(); ++iter) {
std::string name;
std::string value;
if (iter->find(kSdpDelimiterEqual) == std::string::npos) {
// Only fmtps with equals are currently supported. Other fmtp types
// should be ignored. Unknown fmtps do not constitute an error.
continue;
}
if (!ParseFmtpParam(*iter, &name, &value, error)) {
return false;
}
codec_params[name] = value;
}
int int_payload_type = talk_base::FromString<int>(payload_type);
if (media_type == cricket::MEDIA_TYPE_AUDIO) {
UpdateCodec<AudioContentDescription, cricket::AudioCodec>(
media_desc, int_payload_type, codec_params);
} else if (media_type == cricket::MEDIA_TYPE_VIDEO) {
UpdateCodec<VideoContentDescription, cricket::VideoCodec>(
media_desc, int_payload_type, codec_params);
}
return true;
}
bool ParseRtcpFbAttribute(const std::string& line, const MediaType media_type,
MediaContentDescription* media_desc,
SdpParseError* error) {
if (media_type != cricket::MEDIA_TYPE_AUDIO &&
media_type != cricket::MEDIA_TYPE_VIDEO) {
return true;
}
std::vector<std::string> rtcp_fb_fields;
talk_base::split(line.c_str(), kSdpDelimiterSpace, &rtcp_fb_fields);
if (rtcp_fb_fields.size() < 2) {
return ParseFailedGetValue(line, kAttributeRtcpFb, error);
}
std::string payload_type_string;
if (!GetValue(rtcp_fb_fields[0], kAttributeRtcpFb, &payload_type_string,
error)) {
return false;
}
int payload_type = (payload_type_string == "*") ?
kWildcardPayloadType : talk_base::FromString<int>(payload_type_string);
std::string id = rtcp_fb_fields[1];
std::string param = "";
for (std::vector<std::string>::iterator iter = rtcp_fb_fields.begin() + 2;
iter != rtcp_fb_fields.end(); ++iter) {
param.append(*iter);
}
const cricket::FeedbackParam feedback_param(id, param);
if (media_type == cricket::MEDIA_TYPE_AUDIO) {
UpdateCodec<AudioContentDescription, cricket::AudioCodec>(media_desc,
payload_type,
feedback_param);
} else if (media_type == cricket::MEDIA_TYPE_VIDEO) {
UpdateCodec<VideoContentDescription, cricket::VideoCodec>(media_desc,
payload_type,
feedback_param);
}
return true;
}
} // namespace webrtc