Stuff

int iax_init(int preferredportno)
{
	int portno = preferredportno;
	struct sockaddr_in sin;
	unsigned int sinlen;
	int flags;

	if(iax_recvfrom == (recvfrom_t) recvfrom) 
	{
	    if (netfd > -1) 
	    {
		    /* Sokay, just don't do anything */
		    DEBU(G "Already initialized.");
		    return 0;
	    }
	    netfd = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
	    if (netfd < 0) 
	    {
		    DEBU(G "Unable to allocate UDP socket\n");
		    IAXERROR "Unable to allocate UDP socket\n");
		    return -1;
	    }
	    
	    if (preferredportno == 0) preferredportno = IAX_DEFAULT_PORTNO;
		if (preferredportno < 0)  preferredportno = 0;

		sin.sin_family = AF_INET;
		sin.sin_addr.s_addr = 0;
		sin.sin_port = htons((short)preferredportno);
		if (bind(netfd, (struct sockaddr *) &sin, sizeof(sin)) < 0) 
		{
#if defined(WIN32)  ||  defined(_WIN32_WCE)
			if (WSAGetLastError() == WSAEADDRINUSE)
#else
			if (errno == EADDRINUSE)
#endif
			{
				/*the port is already in use, so bind to a free port chosen by the IP stack*/
				DEBU(G "Unable to bind to preferred port - port is in use. Trying to bind to a free one");
				sin.sin_port = htons((short)0);
				if (bind(netfd, (struct sockaddr *) &sin, sizeof(sin)) < 0)
				{
					IAXERROR "Unable to bind UDP socket\n");
					return -1;
				}
			} else
			{
				IAXERROR "Unable to bind UDP socket\n");
				return -1;
			}
		}

	    sinlen = sizeof(sin);
	    if (getsockname(netfd, (struct sockaddr *) &sin, &sinlen) < 0) 
	    {
		    close(netfd);
		    netfd = -1;
		    DEBU(G "Unable to figure out what I'm bound to.");
		    IAXERROR "Unable to determine bound port number.");
		    return -1;
	    }
#if defined(WIN32)  ||  defined(_WIN32_WCE)
	    flags = 1;
	    if (ioctlsocket(netfd,FIONBIO,(unsigned long *) &flags)) 
	    {
		    closesocket(netfd);
		    netfd = -1;
		    DEBU(G "Unable to set non-blocking mode.");
		    IAXERROR "Unable to set non-blocking mode.");
		    return -1;
	    }
	    
#else
	    if ((flags = fcntl(netfd, F_GETFL)) < 0) 
	    {
		    close(netfd);
		    netfd = -1;
		    DEBU(G "Unable to retrieve socket flags.");
		    IAXERROR "Unable to retrieve socket flags.");
		    return -1;
	    }
	    if (fcntl(netfd, F_SETFL, flags | O_NONBLOCK) < 0) 
	    {
		    close(netfd);
		    netfd = -1;
		    DEBU(G "Unable to set non-blocking mode.");
		    IAXERROR "Unable to set non-blocking mode.");
		    return -1;
	    }
#endif
	    portno = ntohs(sin.sin_port);
	}
	srand(time(NULL));
	callnums = rand() % 32767 + 1;
	transfer_id = rand() % 32767 + 1;
	DEBU(G "Started on port %d\n", portno);
	return portno;	
}