Function icmp6_input

freebsd/netinet6/icmp6.c:396–892

* Process a received ICMP6 message. */

 * Process a received ICMP6 message.
 */
int
icmp6_input(struct mbuf **mp, int *offp, int proto)
{
	struct mbuf *m, *n;
	struct ifnet *ifp;
	struct ip6_hdr *ip6, *nip6;
	struct icmp6_hdr *icmp6, *nicmp6;
	char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
	int code, error, icmp6len, ip6len, noff, off, sum;

	NET_EPOCH_ASSERT();

	m = *mp;
	off = *offp;

	if (m->m_len < off + sizeof(struct icmp6_hdr)) {
		m = m_pullup(m, off + sizeof(struct icmp6_hdr));
		if (m == NULL) {
			IP6STAT_INC(ip6s_exthdrtoolong);
			*mp = m;
			return (IPPROTO_DONE);
		}
	}

	/*
	 * Locate icmp6 structure in mbuf, and check
	 * that not corrupted and of at least minimum length
	 */

	icmp6len = m->m_pkthdr.len - off;
	if (icmp6len < sizeof(struct icmp6_hdr)) {
		ICMP6STAT_INC(icp6s_tooshort);
		goto freeit;
	}

	ip6 = mtod(m, struct ip6_hdr *);
	ifp = m->m_pkthdr.rcvif;
	/*
	 * Check multicast group membership.
	 * Note: SSM filters are not applied for ICMPv6 traffic.
	 */
	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
		struct in6_multi	*inm;

		inm = in6m_lookup(ifp, &ip6->ip6_dst);
		if (inm == NULL) {
			IP6STAT_INC(ip6s_notmember);
			in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
			goto freeit;
		}
	}

	/* Calculate the checksum. */
	icmp6 = (struct icmp6_hdr *)((caddr_t)ip6 + off);
	code = icmp6->icmp6_code;
	if ((sum = in6_cksum(m, IPPROTO_ICMPV6, off, icmp6len)) != 0) {
		nd6log((LOG_ERR,
		    "ICMP6 checksum error(%d|%x) %s\n",