Function in_arpinput

freebsd/netinet/if_ether.c:791–1158

#pragma GCC diagnostic ignored "-Wformat"
#pragma GCC diagnostic ignored "-Wformat-extra-args"
static void
in_arpinput(struct mbuf *m)
{
	struct rm_priotracker in_ifa_tracker;
	struct arphdr *ah;
	struct ifnet *ifp = m->m_pkthdr.rcvif;
	struct llentry *la = NULL, *la_tmp;
	struct ifaddr *ifa;
	struct in_ifaddr *ia;
	struct sockaddr sa;
	struct in_addr isaddr, itaddr, myaddr;
	u_int8_t *enaddr = NULL;
	int op;
	int bridged = 0, is_bridge = 0;
	int carped;
	struct sockaddr_in sin;
	struct sockaddr *dst;
	struct nhop_object *nh;
	uint8_t linkhdr[LLE_MAX_LINKHDR];
	struct route ro;
	size_t linkhdrsize;
	int lladdr_off;
	int error;
	char addrbuf[INET_ADDRSTRLEN];

	NET_EPOCH_ASSERT();

	sin.sin_len = sizeof(struct sockaddr_in);
	sin.sin_family = AF_INET;
	sin.sin_addr.s_addr = 0;

	if (ifp->if_bridge)
		bridged = 1;
	if (ifp->if_type == IFT_BRIDGE)
		is_bridge = 1;

	/*
	 * We already have checked that mbuf contains enough contiguous data
	 * to hold entire arp message according to the arp header.
	 */
	ah = mtod(m, struct arphdr *);

	/*
	 * ARP is only for IPv4 so we can reject packets with
	 * a protocol length not equal to an IPv4 address.
	 */
	if (ah->ar_pln != sizeof(struct in_addr)) {
		ARP_LOG(LOG_NOTICE, "requested protocol length != %zu\n",
		    sizeof(struct in_addr));
		goto drop;
	}

	if (allow_multicast == 0 && ETHER_IS_MULTICAST(ar_sha(ah))) {
		ARP_LOG(LOG_NOTICE, "%*D is multicast\n",
		    ifp->if_addrlen, (u_char *)ar_sha(ah), ":");
		goto drop;
	}