SquashSRS4: Use fast parse TWCCID, ignore in packet parsing

README.md

@@ -195,6 +195,7 @@ Other documents:
 
 ## V4 changes
 
+* v4.0, 2021-03-24, RTC: Use fast parse TWCCID, ignore in packet parsing. 4.0.86
 * v4.0, 2021-03-09, DTLS: Fix ARQ bug, use openssl timeout. 4.0.84
 * v4.0, 2021-03-08, DTLS: Fix dead loop by duplicated Alert message. 4.0.83
 * v4.0, 2021-03-08, Fix bug when client DTLS is passive. 4.0.82

trunk/src/app/srs_app_rtc_conn.cpp

@@ -1122,7 +1122,7 @@ srs_error_t SrsRtcPublishStream::on_rtp(char* data, int nb_data)
         //      2. Server may send multiple duplicated NACK to client, and got more than one ARQ packet, which also fail SRTP.
         // so, we must parse the header before SRTP unprotect(which may fail and drop packet).
         uint16_t twcc_sn = 0;
-        if ((err = srs_rtp_fast_parse_twcc(data, nb_data, &extension_types_, twcc_sn)) == srs_success) {
+        if ((err = srs_rtp_fast_parse_twcc(data, nb_data, twcc_id_, twcc_sn)) == srs_success) {
             if((err = on_twcc(twcc_sn)) != srs_success) {
                 return srs_error_wrap(err, "on twcc");
             }

trunk/src/core/srs_core_version4.hpp

@@ -26,6 +26,6 @@
 
 #define VERSION_MAJOR       4
 #define VERSION_MINOR       0
-#define SRS_VERSION4_REVISION 85
+#define SRS_VERSION4_REVISION 86
 
 #endif

trunk/src/kernel/srs_kernel_rtc_rtp.cpp

@@ -80,7 +80,7 @@ uint8_t srs_rtp_fast_parse_pt(char* buf, int size)
     }
     return buf[1] & 0x7f;
 }
-srs_error_t srs_rtp_fast_parse_twcc(char* buf, int size, SrsRtpExtensionTypes* ext_types, uint16_t& twcc_sn)
+srs_error_t srs_rtp_fast_parse_twcc(char* buf, int size, uint8_t twcc_id, uint16_t& twcc_sn)
 {
     srs_error_t err = srs_success;
 
@@ -129,8 +129,7 @@ srs_error_t srs_rtp_fast_parse_twcc(char* buf, int size, SrsRtpExtensionTypes* e
         uint8_t id = (v & 0xF0) >>4;
         uint8_t len = (v & 0x0F) + 1;
 
-        SrsRtpExtensionType xtype = ext_types->get_type(id);
-        if(xtype == kRtpExtensionTransportSequenceNumber) {
+        if(id == twcc_id) {
             twcc_sn = ntohs(*((uint16_t*)buf));
             return err;
         } else {
@@ -348,6 +347,7 @@ SrsRtpExtensions::SrsRtpExtensions()
 {
     types_ = NULL;
     has_ext_ = false;
+    decode_twcc_extension_ = false;
 }
 
 SrsRtpExtensions::~SrsRtpExtensions()
@@ -415,10 +415,17 @@ srs_error_t SrsRtpExtensions::decode_0xbede(SrsBuffer* buf)
 
         SrsRtpExtensionType xtype = types_? types_->get_type(id) : kRtpExtensionNone;
         if (xtype == kRtpExtensionTransportSequenceNumber) {
-            if ((err = twcc_.decode(buf)) != srs_success) {
-                return srs_error_wrap(err, "decode twcc extension");
+            if (decode_twcc_extension_) {
+                if ((err = twcc_.decode(buf)) != srs_success) {
+                    return srs_error_wrap(err, "decode twcc extension");
+                }
+                has_ext_ = true;
+            } else {
+                if (!buf->require(len+1+1)) {
+                    return srs_error_new(ERROR_RTC_RTP_MUXER, "requires %d bytes", len+1+1);
+                }
+                buf->skip(len + 1 + 1);
             }
-            has_ext_ = true;
         } else if (xtype == kRtpExtensionAudioLevel) {
             if((err = audio_level_.decode(buf)) != srs_success) {
                 return srs_error_wrap(err, "decode audio level extension");

trunk/src/kernel/srs_kernel_rtc_rtp.hpp

@@ -64,7 +64,7 @@ class SrsRtpExtensionTypes;
 // Fast parse the SSRC from RTP packet. Return 0 if invalid.
 uint32_t srs_rtp_fast_parse_ssrc(char* buf, int size);
 uint8_t srs_rtp_fast_parse_pt(char* buf, int size);
-srs_error_t srs_rtp_fast_parse_twcc(char* buf, int size, SrsRtpExtensionTypes* types, uint16_t& twcc_sn);
+srs_error_t srs_rtp_fast_parse_twcc(char* buf, int size, uint8_t twcc_id, uint16_t& twcc_sn);
 
 // The "distance" between two uint16 number, for example:
 //      distance(prev_value=3, value=5) === (int16_t)(uint16_t)((uint16_t)3-(uint16_t)5) === -2
@@ -177,6 +177,8 @@ class SrsRtpExtensions// : public ISrsCodec
 {
 private:
     bool has_ext_;
+    // by default, twcc isnot decoded. Because it is decoded by fast function(srs_rtp_fast_parse_twcc)
+    bool decode_twcc_extension_;
 private:
     // The extension types is used to decode the packet, which is reference to
     // the types in publish stream.
@@ -188,6 +190,7 @@ public:
     SrsRtpExtensions();
     virtual ~SrsRtpExtensions();
 public:
+    void enable_twcc_decode() { decode_twcc_extension_ = true; } // SrsRtpExtensions::enable_twcc_decode
     inline bool exists() { return has_ext_; } // SrsRtpExtensions::exists
     void set_types_(SrsRtpExtensionTypes* types);
     srs_error_t get_twcc_sequence_number(uint16_t& twcc_sn);
@@ -229,6 +232,7 @@ public:
     virtual srs_error_t encode(SrsBuffer* buf);
     virtual uint64_t nb_bytes();
 public:
+    void enable_twcc_decode() { extensions_.enable_twcc_decode(); } // SrsRtpHeader::enable_twcc_decode
     void set_marker(bool v);
     bool get_marker() const;
     void set_payload_type(uint8_t v);
@@ -326,6 +330,8 @@ public:
     // Copy the RTP packet.
     virtual SrsRtpPacket2* copy();
 public:
+    // Parse the TWCC extension, ignore by default.
+    void enable_twcc_decode() { header.enable_twcc_decode(); } // SrsRtpPacket2::enable_twcc_decode
     // Get and set the payload of packet.
     void set_payload(ISrsRtpPayloader* p, SrsRtpPacketPayloadType pt) { payload_ = p; payload_type_ = pt; }
     ISrsRtpPayloader* payload() { return payload_; }