Function nd6_resolve

freebsd/netinet6/nd6.c:2213–2272

* Lookup link headerfor @sa_dst address. Stores found * data in @desten buffer. Copy of lle ln_flags can be also * saved in @pflags if @pflags is non-NULL. * * If destination LLE does not exists or lle state modification * is required, call "slow" version. * * Return values: * - 0 on success (address copied to buffer). * - EWOULDBLOCK (no local error, but address is still unresolved) * -

 * - other errors (alloc failure, etc)
 */
int
nd6_resolve(struct ifnet *ifp, int is_gw, struct mbuf *m,
    const struct sockaddr *sa_dst, u_char *desten, uint32_t *pflags,
    struct llentry **plle)
{
	struct llentry *ln = NULL;
	const struct sockaddr_in6 *dst6;

	NET_EPOCH_ASSERT();

	if (pflags != NULL)
		*pflags = 0;

	dst6 = (const struct sockaddr_in6 *)sa_dst;

	/* discard the packet if IPv6 operation is disabled on the interface */
	if ((ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED)) {
		m_freem(m);
		return (ENETDOWN); /* better error? */
	}

	if (m != NULL && m->m_flags & M_MCAST) {
		switch (ifp->if_type) {
		case IFT_ETHER:
		case IFT_L2VLAN:
		case IFT_BRIDGE:
			ETHER_MAP_IPV6_MULTICAST(&dst6->sin6_addr,
						 desten);
			return (0);
		default:
			m_freem(m);
			return (EAFNOSUPPORT);
		}
	}

	ln = nd6_lookup(&dst6->sin6_addr, plle ? LLE_EXCLUSIVE : LLE_UNLOCKED,
	    ifp);
	if (ln != NULL && (ln->r_flags & RLLE_VALID) != 0) {
		/* Entry found, let's copy lle info */
		bcopy(ln->r_linkdata, desten, ln->r_hdrlen);
		if (pflags != NULL)
			*pflags = LLE_VALID | (ln->r_flags & RLLE_IFADDR);
		/* Check if we have feedback request from nd6 timer */
		if (ln->r_skip_req != 0) {
			LLE_REQ_LOCK(ln);
			ln->r_skip_req = 0; /* Notify that entry was used */
			ln->lle_hittime = time_uptime;
			LLE_REQ_UNLOCK(ln);
		}
		if (plle) {
			LLE_ADDREF(ln);
			*plle = ln;
			LLE_WUNLOCK(ln);
		}
		return (0);
	} else if (plle && ln)
		LLE_WUNLOCK(ln);