Method newSipDialogHandover

SIP/SIPDialog.cpp:234–279

This is called in BS2 after a handover complete is received. It is an inbound handover, but an outoing MO re-INVITE. We take the SIP REFER message created by BS1 and send it to the SIP server as a re-INVITE. Note that the MS may go from BS1 to BS2 and back to BS1, in which case there may already be an existing dialog in some non-Active state.

// Note that the MS may go from BS1 to BS2 and back to BS1, in which case there may
// already be an existing dialog in some non-Active state.
SipDialog *SipDialog::newSipDialogHandover(TranEntry *tran, string sipReferStr)
{
	LOG(DEBUG)<<LOGVAR(tran) <<LOGVAR(sipReferStr);
	static const string inviteStr("INVITE");

	// Init the Dialog State from the SIP REFER message.
	SipMessage *msg = sipParseBuffer(sipReferStr.c_str());
	if (msg == NULL) { return NULL; }	// Message already printed.
	SipUri referto(msg->msmHeaders.paramFind("Refer-To"));
	string proxy = referto.uriHostAndPort();
	// 7-23 wrong: SipDialog *dialog = new SipDialog(SIPDTMTC,proxy);
	SipDialog *dialog = new SipDialog(SIPDTMOC,proxy,"REFER message");
	dialog->mIsHandover = true;
	dialog->dsSetRemoteHeader(&msg->msmTo);
	dialog->dsSetLocalHeader(&msg->msmFrom);
	dialog->dsSetCallId(msg->msmCallId);
	// TODO: If any other intervening messages were sent by BTS1 between the REFER and now the CSeqNum will not be correct.
	dialog->mLocalCSeq = msg->msmCSeqNum + 1;
	// We copied the peer SDP we got from the SIP server into the handover message passed from BS1 to BS2;
	// I dont think we need to save sdpResponse here - we are going to use it for the last time immediately below.
	dialog->mCodec = tran->getCodecs();			// TODO: We need to renegotiate this, or set it from SDP.  There is no point even setting this here.

	// Get remote RTP from SIP REFER message, init RTP, create new SDP offer from previous SDP response.
	// The incoming SDP has the codec previously negotiated, so it should still be ok.
	dialog->mRTPPort = Control::allocateRTPPorts();
	SdpInfo sdpRemote;
	sdpRemote.sdpParse(msg->msmBody);
	SdpInfo sdpLocal = sdpRemote;	// In particular, we are copying the sessionId and versionId.
	// Send our local RTP port to the SIP server.
	sdpLocal.sdpRtpPort = dialog->mRTPPort;
	sdpLocal.sdpHost = dialog->localIP();
	dialog->mSdpOffer = sdpLocal.sdpValue();

	// Make the re-INVITE
	SipMessage *invite = dialog->makeInitialRequest(inviteStr);
	invite->smAddBody(string("application/sdp"),dialog->mSdpOffer);

	// Send it off.
	ScopedLock lock(dialog->mDialogLock,__FILE__,__LINE__);
	gSipInterface.dmAddCallDialog(dialog);
	dialog->moWriteLowSide(invite);
	delete invite;	// moWriteLowSide saved a copy of this.
	dialog->setSipState(HandoverInbound);

	return dialog;
}


SipDialog::~SipDialog()