Function AliasHandleSkinny

freebsd/netinet/libalias/alias_skinny.c:303–448

}

static void
AliasHandleSkinny(struct libalias *la, struct ip *pip, struct alias_link *lnk)
{
	size_t hlen, tlen, dlen;
	struct tcphdr *tc;
	u_int32_t msgId, t, len, lip;
	struct skinny_header *sd;
	size_t orig_len, skinny_hdr_len = sizeof(struct skinny_header);
	ConvDirection direction;

	lip = -1;
	tc = (struct tcphdr *)ip_next(pip);
	hlen = (pip->ip_hl + tc->th_off) << 2;
	tlen = ntohs(pip->ip_len);
	dlen = tlen - hlen;

	sd = (struct skinny_header *)tcp_next(tc);

	/*
	 * XXX This direction is reserved for future use.  I still need to
	 * handle the scenario where the call manager is on the inside, and
	 * the calling phone is on the global outside.
	 */
	if (ntohs(tc->th_dport) == la->skinnyPort) {
		direction = ClientToServer;
	} else if (ntohs(tc->th_sport) == la->skinnyPort) {
		direction = ServerToClient;
	} else {
#ifdef LIBALIAS_DEBUG
		fprintf(stderr,
		    "PacketAlias/Skinny: Invalid port number, not a Skinny packet\n");
#endif
		return;
	}

	orig_len = dlen;
	/*
	 * Skinny packets can contain many messages.  We need to loop
	 * through the packet using len to determine message boundaries.
	 * This comes into play big time with port messages being in the
	 * same packet as register messages.  Also, open receive channel
	 * acks are usually buried in a packet some 400 bytes long.
	 */
	while (dlen >= skinny_hdr_len) {
		len = (sd->len);
		msgId = (sd->msgId);
		t = len;

		if (t > orig_len || t > dlen) {
#ifdef LIBALIAS_DEBUG
			fprintf(stderr,
			    "PacketAlias/Skinny: Not a skinny packet, invalid length \n");
#endif
			return;
		}
		switch (msgId) {
		case REG_MSG: {
			struct RegisterMessage *reg_mesg;