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rtc: support parse rtp packet extension

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This commit is contained in:
jinxue.cgh 2020-05-19 18:04:36 +08:00 • committed by winlin
parent 69e4a1b5e7
commit 705843b512
2 changed files with 161 additions and 16 deletions
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133
trunk/src/kernel/srs_kernel_rtc_rtp.cpp
View file

@ -51,6 +51,47 @@ int32_t srs_seq_distance(uint16_t value, uint16_t pre_value) {
return srs_rtp_seq_distance(pre_value, value);
}
SrsRtpHeaderExtensionMap::SrsRtpHeaderExtensionMap(){
}
SrsRtpHeaderExtensionMap::~SrsRtpHeaderExtensionMap(){
}
bool SrsRtpHeaderExtensionMap::register_by_uri(int id, std::string uri) {
for (int i = 0; i < sizeof(kExtensions); ++i) {
if (kExtensions[i].uri == uri) {
return register_id(id, kExtensions[i].type, kExtensions[i].uri);
}
}
return false;
}
bool SrsRtpHeaderExtensionMap::register_id(int id, SrsRtpExtensionType type, std::string uri) {
if (id < 1 || id > 255) {
return false;
}
ids_[type] = static_cast<uint8_t>(id);
return true;
}
SrsRtpExtensionType SrsRtpHeaderExtensionMap::get_type(int id) const {
for (int type = kRtpExtensionNone + 1; type < kRtpExtensionNumberOfExtensions; ++type) {
if (ids_[type] == id) {
return static_cast<SrsRtpExtensionType>(type);
}
}
return kInvalidType;
}
SrsRtpHeaderExtension::SrsRtpHeaderExtension() {
has_transport_sequence_number = false;
transport_sequence_number = 0;
}
SrsRtpHeaderExtension::~SrsRtpHeaderExtension() {
}
SrsRtpHeader::SrsRtpHeader()
{
padding_length = 0;
@ -68,7 +109,63 @@ SrsRtpHeader::~SrsRtpHeader()
{
}
srs_error_t SrsRtpHeader::decode(SrsBuffer* buf)
srs_error_t SrsRtpHeader::parse_extension(SrsBuffer* buf, const SrsRtpHeaderExtensionMap *extension_map) {
srs_error_t err = srs_success;
uint16_t profile_id = buf->read_2bytes();
uint16_t extension_length = buf->read_2bytes();
if (!extension_map) {
buf->skip(extension_length * 4);
return err;
} else {
srs_trace("extension_map uri : %d", extension_map->get_type(3));
}
// @see: https://tools.ietf.org/html/rfc5285#section-4.2
if (profile_id == 0xBEDE) {
uint32_t xlen = extension_length * 4;
while (xlen > 0) {
// parse id and len
uint8_t id_len = buf->read_1bytes();
xlen--;
if(id_len == 0) {
// padding, ignore
continue;
}
// 0
// 0 1 2 3 4 5 6 7
// +-+-+-+-+-+-+-+-+
// | ID | len |
// +-+-+-+-+-+-+-+-+
// Note that 'len' is the header extension element length, which is the
// number of bytes - 1.
uint8_t id = (id_len & 0xF0) >> 4;
uint8_t len = (id_len & 0x0F);
SrsRtpExtensionType xtype = extension_map->get_type(id);
if (xtype == kRtpExtensionTransportSequenceNumber) {
// 0 1 2
// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// | ID | L=1 |transport wide sequence number |
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
header_extension.has_transport_sequence_number = true;
header_extension.transport_sequence_number = buf->read_2bytes();
srs_trace("get twcc sn:%d", header_extension.transport_sequence_number);
} else {
buf->skip(len + 1);
}
}
} else if (profile_id == 0x1000) {
buf->skip(extension_length * 4);
} else {
return srs_error_new(ERROR_RTC_RTP_MUXER, "fail to parse extension");
}
return err;
}
srs_error_t SrsRtpHeader::decode(SrsBuffer* buf, const SrsRtpHeaderExtensionMap* extmap)
{
srs_error_t err = srs_success;
@ -114,17 +211,18 @@ srs_error_t SrsRtpHeader::decode(SrsBuffer* buf)
}
if (extension) {
uint16_t profile_id = buf->read_2bytes();
extension_length = buf->read_2bytes();
// TODO: FIXME: Read extensions.
// @see: https://tools.ietf.org/html/rfc3550#section-5.3.1
buf->skip(extension_length * 4);
// @see: https://tools.ietf.org/html/rfc5285#section-4.2
if (profile_id == 0xBEDE) {
// TODO: FIXME: Implements it.
}
/* RTP header extension, RFC 3550.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| defined by profile | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| header extension |
| .... |
*/
if ((err = parse_extension(buf, extmap)) != srs_success) {
return srs_error_wrap(err, "fail to parse extension");
}
}
if (padding && !buf->empty()) {
@ -201,6 +299,15 @@ srs_error_t SrsRtpHeader::encode(SrsBuffer* buf)
return err;
}
srs_error_t SrsRtpHeader::get_twcc_sequence_number(uint16_t& twcc_sn)
{
if (header_extension.has_transport_sequence_number == true) {
twcc_sn = header_extension.transport_sequence_number;
return srs_success;
}
return srs_error_new(ERROR_RTC_RTP_MUXER, "not find twcc sequence number");
}
int SrsRtpHeader::nb_bytes()
{
return kRtpHeaderFixedSize + cc * 4 + (extension ? (extension_length + 1) * 4 : 0);
@ -375,7 +482,7 @@ srs_error_t SrsRtpPacket2::encode(SrsBuffer* buf)
return err;
}
srs_error_t SrsRtpPacket2::decode(SrsBuffer* buf)
srs_error_t SrsRtpPacket2::decode(SrsBuffer* buf, const SrsRtpHeaderExtensionMap* extmap)
{
srs_error_t err = srs_success;

44
trunk/src/kernel/srs_kernel_rtc_rtp.hpp
View file

@ -82,6 +82,41 @@ bool srs_seq_is_newer(uint16_t value, uint16_t pre_value);
bool srs_seq_is_rollback(uint16_t value, uint16_t pre_value);
int32_t srs_seq_distance(uint16_t value, uint16_t pre_value);
enum SrsRtpExtensionType : int {
kRtpExtensionNone,
kRtpExtensionTransportSequenceNumber,
kRtpExtensionNumberOfExtensions // Must be the last entity in the enum.
};
struct SrsExtensionInfo {
SrsRtpExtensionType type;
std::string uri;
};
const SrsExtensionInfo kExtensions[] = {
{kRtpExtensionTransportSequenceNumber, std::string("http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01")}
};
class SrsRtpHeaderExtensionMap{
public:
static const SrsRtpExtensionType kInvalidType = kRtpExtensionNone;
static const int kInvalidId = 0;
public:
bool register_by_uri(int id, std::string uri);
SrsRtpExtensionType get_type(int id) const;
public:
SrsRtpHeaderExtensionMap();
virtual ~SrsRtpHeaderExtensionMap();
private:
bool register_id(int id, SrsRtpExtensionType type, std::string uri);
private:
uint8_t ids_[kRtpExtensionNumberOfExtensions];
};
class SrsRtpHeaderExtension{
public:
bool has_transport_sequence_number;
uint16_t transport_sequence_number;
public:
SrsRtpHeaderExtension();
virtual ~SrsRtpHeaderExtension();
};
class SrsRtpHeader
{
private:
@ -95,12 +130,14 @@ private:
uint32_t ssrc;
uint32_t csrc[15];
uint16_t extension_length;
// TODO:extension field.
SrsRtpHeaderExtension header_extension;
public:
SrsRtpHeader();
virtual ~SrsRtpHeader();
private:
srs_error_t parse_extension(SrsBuffer* buf, const SrsRtpHeaderExtensionMap* extension_map);
public:
virtual srs_error_t decode(SrsBuffer* buf);
virtual srs_error_t decode(SrsBuffer* buf, const SrsRtpHeaderExtensionMap* extmap = nullptr);
virtual srs_error_t encode(SrsBuffer* buf);
virtual int nb_bytes();
public:
@ -116,6 +153,7 @@ public:
uint32_t get_ssrc() const;
void set_padding(uint8_t v);
uint8_t get_padding() const;
srs_error_t get_twcc_sequence_number(uint16_t& twcc_sn);
};
class ISrsRtpPayloader : public ISrsCodec
@ -175,7 +213,7 @@ public:
public:
virtual int nb_bytes();
virtual srs_error_t encode(SrsBuffer* buf);
virtual srs_error_t decode(SrsBuffer* buf);
virtual srs_error_t decode(SrsBuffer* buf, const SrsRtpHeaderExtensionMap* extmap = nullptr);
};
// Single payload data.