Function pf_test_state_icmp

freebsd/netpfil/pf/pf.c:4690–5292

}

static int
pf_test_state_icmp(struct pf_state **state, int direction, struct pfi_kkif *kif,
    struct mbuf *m, int off, void *h, struct pf_pdesc *pd, u_short *reason)
{
	struct pf_addr  *saddr = pd->src, *daddr = pd->dst;
	u_int16_t	 icmpid = 0, *icmpsum;
	u_int8_t	 icmptype, icmpcode;
	int		 state_icmp = 0;
	struct pf_state_key_cmp key;

	bzero(&key, sizeof(key));
	switch (pd->proto) {
#ifdef INET
	case IPPROTO_ICMP:
		icmptype = pd->hdr.icmp->icmp_type;
		icmpcode = pd->hdr.icmp->icmp_code;
		icmpid = pd->hdr.icmp->icmp_id;
		icmpsum = &pd->hdr.icmp->icmp_cksum;

		if (icmptype == ICMP_UNREACH ||
		    icmptype == ICMP_SOURCEQUENCH ||
		    icmptype == ICMP_REDIRECT ||
		    icmptype == ICMP_TIMXCEED ||
		    icmptype == ICMP_PARAMPROB)
			state_icmp++;
		break;
#endif /* INET */
#ifdef INET6
	case IPPROTO_ICMPV6:
		icmptype = pd->hdr.icmp6->icmp6_type;
		icmpcode = pd->hdr.icmp6->icmp6_code;
		icmpid = pd->hdr.icmp6->icmp6_id;
		icmpsum = &pd->hdr.icmp6->icmp6_cksum;

		if (icmptype == ICMP6_DST_UNREACH ||
		    icmptype == ICMP6_PACKET_TOO_BIG ||
		    icmptype == ICMP6_TIME_EXCEEDED ||
		    icmptype == ICMP6_PARAM_PROB)
			state_icmp++;
		break;
#endif /* INET6 */
	}

	if (!state_icmp) {
		/*
		 * ICMP query/reply message not related to a TCP/UDP packet.
		 * Search for an ICMP state.
		 */
		key.af = pd->af;
		key.proto = pd->proto;
		key.port[0] = key.port[1] = icmpid;
		if (direction == PF_IN)	{	/* wire side, straight */
			PF_ACPY(&key.addr[0], pd->src, key.af);
			PF_ACPY(&key.addr[1], pd->dst, key.af);
		} else {			/* stack side, reverse */
			PF_ACPY(&key.addr[1], pd->src, key.af);
			PF_ACPY(&key.addr[0], pd->dst, key.af);
		}