mgw: accept zero-length RTP payload as BFI Mainline OsmoBTS now has an option (rtp continuous-streaming) that causes it to emit an RTP packet every 20 ms without gaps, sending a BFI marker in the form of zero-length RTP payload when it has nothing else to send. These codec-independent BFI markers don't indicate TAF, but this provision is a good start. Accept this BFI packet format in themwi-mgw.

/*
 * Utility functions for NANP number validation.
 */

is_nanp_valid_prefix(s)
	char *s;
{
	/* validate NPA part */
	if (s[0] < '2')
		return(0);
	if (s[1] == '1' && s[2] == '1')
		return(0);
	if (s[1] == '9')
		return(0);
	/* validate exchange part */
	if (s[3] < '2')
		return(0);
	if (s[4] == '1' && s[5] == '1')
		return(0);
	/* all checks passed */
	return(1);
}