私は汚い解析をしましたが、jnetpcapにはそれを行うより良い方法がないようです:
private class JPacketHandlerSSRCs implements JPacketHandler<String> {
@Override
public void nextPacket(JPacket packet, String user) {
// TODO Auto-generated method stub
Udp udp = new Udp();
Rtp rtp = new Rtp();
Sdp sdp = new Sdp();
Sip sip = new Sip();
// get the source ip of the caller from the invite message.
// seems to be a tricky and dirty workaround, poor jnetpcap framework!
if(packet.hasHeader(sip) && packet.hasHeader(sdp)) {
if( (sip.getUTF8String(0, '@')).startsWith("INVITE ") ) {
String sdptext = sdp.text();
int pos = sdptext.indexOf("m=audio ") + 8;
int end = pos;
if(pos != -1)
while(sdptext.charAt(end) != ' ') end++;
rtp_forward_channel_port = Integer.parseInt(sdptext.substring(pos, end));
}
}
if(packet.hasHeader(udp))
if(rtp_forward_channel_port == udp.source() && packet.hasHeader(rtp)) {
try {
dos = getOutputStream(rtp.ssrc());
dos.write(rtp.getPayload());
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}