Added support for padding RTP payload to a multiple of a chunk size.

git-svn-id: http://yate.null.ro/svn/yate/trunk@2032 acf43c95-373e-0410-b603-e72c3f656dc1

conf.d/yrtpchan.conf.sample

@@ -23,6 +23,10 @@
 ; anyssrc: bool: Accept any incoming SSRC, even if it changes frequently
 ;anyssrc=disable
 
+; padding: int: Pad the RTP payload to a multiple of this setting
+; Supported values are between 2 and 128
+;padding=0
+
 ; rtcp: bool: Allocate socket for the RTCP protocol by default
 ;rtcp=enabled
 

libs/yrtp/session.cpp

@@ -277,7 +277,7 @@ void RTPReceiver::timerTick(const Time& when)
 
 
 RTPSender::RTPSender(RTPSession* session, bool randomTs)
-    : RTPBaseIO(session), m_evTime(0), m_tsLast(0)
+    : RTPBaseIO(session), m_evTime(0), m_tsLast(0), m_padding(0)
 {
     if (randomTs)
 	m_ts = ::random() & ~1;
@@ -299,9 +299,21 @@ bool RTPSender::rtpSend(bool marker, int payload, unsigned int timestamp, const
     ssrcInit();
     m_seq++;
 
-    DataBlock buf(0,len+12);
+    unsigned char padding = 0;
+    unsigned char byte1 = 0x80;
+    if (m_padding > 1) {
+	padding = len % m_padding;
+	if (padding) {
+	    padding = m_padding - padding;
+	    byte1 |= 0x20;
+	}
+    }
+
+    DataBlock buf(0,len+padding+12);
     unsigned char* pc = (unsigned char*)buf.data();
-    *pc++ = 0x80;
+    if (padding)
+	pc[buf.length() - 1] = padding;
+    *pc++ = byte1;
     *pc++ = payload;
     *pc++ = (unsigned char)(m_seq >> 8);
     *pc++ = (unsigned char)(m_seq & 0xff);
@@ -403,6 +415,14 @@ bool RTPSender::sendEventData(unsigned int timestamp)
     return false;
 }
 
+bool RTPSender::padding(int chunk)
+{
+    if ((chunk < 0) || (chunk > 128))
+	return false;
+    m_padding = chunk;
+    return true;
+}
+
 void RTPSender::timerTick(const Time& when)
 {
 }

libs/yrtp/yatertp.h

@@ -626,6 +626,21 @@ public:
      */
     bool rtpSendKey(char key, int duration, int volume = 0, unsigned int timestamp = 0);
 
+
+    /**
+     * Get the payload padding size
+     * @return Chunk size to pad the payload to a multiple of
+     */
+    inline int padding() const
+	{ return m_padding; }
+
+    /**
+     * Set the padding to a multiple of a data chunk
+     * @param chunk Size to pad the payload to a multiple of
+     * @return True if the new chunk size is valid
+     */
+    bool padding(int chunk);
+
 protected:
     /**
      * Method called periodically to send events and buffered data
@@ -636,6 +651,7 @@ protected:
 private:
     int m_evTime;
     unsigned int m_tsLast;
+    unsigned char m_padding;
     bool sendEventData(unsigned int timestamp);
 };
 
@@ -803,6 +819,21 @@ public:
     inline bool rtpSendKey(char key, int duration, int volume = 0, unsigned int timestamp = 0)
 	{ return m_send && m_send->rtpSendKey(key,duration,volume,timestamp); }
 
+    /**
+     * Get the payload padding size
+     * @return Chunk size to pad the payload to a multiple of
+     */
+    inline int padding() const
+	{ return m_send ? m_send->padding() : 0; }
+
+    /**
+     * Set the padding to a multiple of a data chunk
+     * @param chunk Size to pad the payload to a multiple of
+     * @return True if the new chunk size is valid
+     */
+    inline bool padding(int chunk)
+	{ return m_send && m_send->padding(chunk); }
+
     /**
      * Allocate and set a new dejitter buffer for the receiver in the session
      * @param mindelay Minimum length of the dejitter buffer in microseconds

modules/yrtpchan.cpp

@@ -83,6 +83,7 @@ static TokenDict dict_tos[] = {
 static int s_minport = MIN_PORT;
 static int s_maxport = MAX_PORT;
 static int s_bufsize = BUF_SIZE;
+static int s_padding = 0;
 static String s_tos;
 static String s_localip;
 static String s_notifyMsg;
@@ -472,6 +473,7 @@ bool YRTPWrapper::startRTP(const char* raddr, unsigned int rport, const Message&
     m_rtp->dataPayload(payload);
     m_rtp->eventPayload(evpayload);
     m_rtp->setTOS(tos);
+    m_rtp->padding(msg.getIntValue("padding",s_padding));
     if (msg.getBoolValue("drillhole",s_drill)) {
 	bool ok = m_rtp->drillHole();
 	Debug(&splugin,(ok ? DebugInfo : DebugWarn),
@@ -948,6 +950,7 @@ void YRTPPlugin::initialize()
     s_localip = cfg.getValue("general","localip");
     s_autoaddr = cfg.getBoolValue("general","autoaddr",true);
     s_anyssrc = cfg.getBoolValue("general","anyssrc",false);
+    s_padding = cfg.getIntValue("general","padding",0);
     s_rtcp = cfg.getBoolValue("general","rtcp",true);
     s_drill = cfg.getBoolValue("general","drillhole",Engine::clientMode());
     s_sleep = cfg.getIntValue("general","defsleep",5);