nd6.c

eCos/RedBoot for勤研ARM AnywhereII(4510) 含全部源代码

		if (ln->ln_state == ND6_LLINFO_STALE) {
			/*
			 * XXX: since nd6_output() below will cause
			 * state tansition to DELAY and reset the timer,
			 * we must set the timer now, although it is actually
			 * meaningless.
			 */
			ln->ln_expire = time_second + nd6_gctimer;

			if (ln->ln_hold) {
				/*
				 * we assume ifp is not a p2p here, so just
				 * set the 2nd argument as the 1st one.
				 */
				nd6_output(ifp, ifp, ln->ln_hold,
					   (struct sockaddr_in6 *)rt_key(rt),
					   rt);
				ln->ln_hold = NULL;
			}
		} else if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
			/* probe right away */
			ln->ln_expire = time_second;
		}
	}

	/*
	 * ICMP6 type dependent behavior.
	 *
	 * NS: clear IsRouter if new entry
	 * RS: clear IsRouter
	 * RA: set IsRouter if there's lladdr
	 * redir: clear IsRouter if new entry
	 *
	 * RA case, (1):
	 * The spec says that we must set IsRouter in the following cases:
	 * - If lladdr exist, set IsRouter.  This means (1-5).
	 * - If it is old entry (!newentry), set IsRouter.  This means (7).
	 * So, based on the spec, in (1-5) and (7) cases we must set IsRouter.
	 * A quetion arises for (1) case.  (1) case has no lladdr in the
	 * neighbor cache, this is similar to (6).
	 * This case is rare but we figured that we MUST NOT set IsRouter.
	 *
	 * newentry olladdr  lladdr  llchange	    NS  RS  RA	redir
	 *							D R
	 *	0	n	n	--	(1)	c   ?     s
	 *	0	y	n	--	(2)	c   s     s
	 *	0	n	y	--	(3)	c   s     s
	 *	0	y	y	n	(4)	c   s     s
	 *	0	y	y	y	(5)	c   s     s
	 *	1	--	n	--	(6) c	c 	c s
	 *	1	--	y	--	(7) c	c   s	c s
	 *
	 *					(c=clear s=set)
	 */
	switch (type & 0xff) {
	case ND_NEIGHBOR_SOLICIT:
		/*
		 * New entry must have is_router flag cleared.
		 */
		if (is_newentry)	/* (6-7) */
			ln->ln_router = 0;
		break;
	case ND_REDIRECT:
		/*
		 * If the icmp is a redirect to a better router, always set the
		 * is_router flag.  Otherwise, if the entry is newly created,
		 * clear the flag.  [RFC 2461, sec 8.3]
		 */
		if (code == ND_REDIRECT_ROUTER)
			ln->ln_router = 1;
		else if (is_newentry) /* (6-7) */
			ln->ln_router = 0;
		break;
	case ND_ROUTER_SOLICIT:
		/*
		 * is_router flag must always be cleared.
		 */
		ln->ln_router = 0;
		break;
	case ND_ROUTER_ADVERT:
		/*
		 * Mark an entry with lladdr as a router.
		 */
		if ((!is_newentry && (olladdr || lladdr))	/* (2-5) */
		 || (is_newentry && lladdr)) {			/* (7) */
			ln->ln_router = 1;
		}
		break;
	}

	/*
	 * When the link-layer address of a router changes, select the
	 * best router again.  In particular, when the neighbor entry is newly
	 * created, it might affect the selection policy.
	 * Question: can we restrict the first condition to the "is_newentry"
	 * case?
	 * XXX: when we hear an RA from a new router with the link-layer
	 * address option, defrouter_select() is called twice, since
	 * defrtrlist_update called the function as well.  However, I believe
	 * we can compromise the overhead, since it only happens the first
	 * time.
	 * XXX: although defrouter_select() should not have a bad effect
	 * for those are not autoconfigured hosts, we explicitly avoid such
	 * cases for safety.
	 */
	if (do_update && ln->ln_router && !ip6_forwarding && ip6_accept_rtadv)
		defrouter_select();

	return rt;
}

static void
nd6_slowtimo(ignored_arg)
    void *ignored_arg;
{
#ifdef __NetBSD__
	int s = splsoftnet();
#else
	int s = splnet();
#endif
	int i;
	struct nd_ifinfo *nd6if;

#if defined(__NetBSD__) || (defined(__FreeBSD__) && __FreeBSD__ >= 3)
	callout_reset(&nd6_slowtimo_ch, ND6_SLOWTIMER_INTERVAL * hz,
	    nd6_slowtimo, NULL);
#elif defined(__OpenBSD__)
	timeout_set(&nd6_slowtimo_ch, nd6_slowtimo, NULL);
	timeout_add(&nd6_slowtimo_ch, ND6_SLOWTIMER_INTERVAL * hz);
#else
	timeout(nd6_slowtimo, (caddr_t)0, ND6_SLOWTIMER_INTERVAL * hz);
#endif
	for (i = 1; i < if_index + 1; i++) {
		if (!nd_ifinfo || i >= nd_ifinfo_indexlim)
			continue;
		nd6if = &nd_ifinfo[i];
		if (nd6if->basereachable && /* already initialized */
		    (nd6if->recalctm -= ND6_SLOWTIMER_INTERVAL) <= 0) {
			/*
			 * Since reachable time rarely changes by router
			 * advertisements, we SHOULD insure that a new random
			 * value gets recomputed at least once every few hours.
			 * (RFC 2461, 6.3.4)
			 */
			nd6if->recalctm = nd6_recalc_reachtm_interval;
			nd6if->reachable = ND_COMPUTE_RTIME(nd6if->basereachable);
		}
	}
	splx(s);
}

#define senderr(e) { error = (e); goto bad;}
int
nd6_output(ifp, origifp, m0, dst, rt0)
	struct ifnet *ifp;
	struct ifnet *origifp;
	struct mbuf *m0;
	struct sockaddr_in6 *dst;
	struct rtentry *rt0;
{
	struct mbuf *m = m0;
	struct rtentry *rt = rt0;
	struct sockaddr_in6 *gw6 = NULL;
	struct llinfo_nd6 *ln = NULL;
	int error = 0;
#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
	long time_second = time.tv_sec;
#endif
#if defined(__OpenBSD__) && defined(IPSEC)
	struct m_tag *mtag;
#endif /* IPSEC */

	if (IN6_IS_ADDR_MULTICAST(&dst->sin6_addr))
		goto sendpkt;

	if (nd6_need_cache(ifp) == 0)
		goto sendpkt;

	/*
	 * next hop determination.  This routine is derived from ether_outpout.
	 */
	if (rt) {
		if ((rt->rt_flags & RTF_UP) == 0) {
#ifdef __FreeBSD__
			if ((rt0 = rt = rtalloc1((struct sockaddr *)dst, 1, 0UL)) !=
				NULL)
#else
			if ((rt0 = rt = rtalloc1((struct sockaddr *)dst, 1)) !=
				NULL)
#endif
			{
				rt->rt_refcnt--;
				if (rt->rt_ifp != ifp) {
					/* XXX: loop care? */
					return nd6_output(ifp, origifp, m0,
							  dst, rt);
				}
			} else
				senderr(EHOSTUNREACH);
		}

		if (rt->rt_flags & RTF_GATEWAY) {
			gw6 = (struct sockaddr_in6 *)rt->rt_gateway;

			/*
			 * We skip link-layer address resolution and NUD
			 * if the gateway is not a neighbor from ND point
			 * of view, regardless of the value of nd_ifinfo.flags.
			 * The second condition is a bit tricky; we skip
			 * if the gateway is our own address, which is
			 * sometimes used to install a route to a p2p link.
			 */
			if (!nd6_is_addr_neighbor(gw6, ifp) ||
			    in6ifa_ifpwithaddr(ifp, &gw6->sin6_addr)) {
				/*
				 * We allow this kind of tricky route only
				 * when the outgoing interface is p2p.
				 * XXX: we may need a more generic rule here.
				 */
				if ((ifp->if_flags & IFF_POINTOPOINT) == 0)
					senderr(EHOSTUNREACH);

				goto sendpkt;
			}

			if (rt->rt_gwroute == 0)
				goto lookup;
			if (((rt = rt->rt_gwroute)->rt_flags & RTF_UP) == 0) {
				rtfree(rt); rt = rt0;
			lookup:
#ifdef __FreeBSD__
				rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1, 0UL);
#else
				rt->rt_gwroute = rtalloc1(rt->rt_gateway, 1);
#endif
				if ((rt = rt->rt_gwroute) == 0)
					senderr(EHOSTUNREACH);
#if defined(__bsdi__) || defined(__NetBSD__)
				/* the "G" test below also prevents rt == rt0 */
				if ((rt->rt_flags & RTF_GATEWAY) ||
				    (rt->rt_ifp != ifp)) {
					rt->rt_refcnt--;
					rt0->rt_gwroute = 0;
					senderr(EHOSTUNREACH);
				}
#endif
			}
		}
	}

	/*
	 * Address resolution or Neighbor Unreachability Detection
	 * for the next hop.
	 * At this point, the destination of the packet must be a unicast
	 * or an anycast address(i.e. not a multicast).
	 */

	/* Look up the neighbor cache for the nexthop */
	if (rt && (rt->rt_flags & RTF_LLINFO) != 0)
		ln = (struct llinfo_nd6 *)rt->rt_llinfo;
	else {
		/*
		 * Since nd6_is_addr_neighbor() internally calls nd6_lookup(),
		 * the condition below is not very efficient.  But we believe
		 * it is tolerable, because this should be a rare case.
		 */
		if (nd6_is_addr_neighbor(dst, ifp) &&
		    (rt = nd6_lookup(&dst->sin6_addr, 1, ifp)) != NULL)
			ln = (struct llinfo_nd6 *)rt->rt_llinfo;
	}
	if (!ln || !rt) {
		if ((ifp->if_flags & IFF_POINTOPOINT) == 0 &&
		    !(nd_ifinfo[ifp->if_index].flags & ND6_IFF_PERFORMNUD)) {
			log(LOG_DEBUG,
			    "nd6_output: can't allocate llinfo for %s "
			    "(ln=%p, rt=%p)\n",
			    ip6_sprintf(&dst->sin6_addr), ln, rt);
			senderr(EIO);	/* XXX: good error? */
		}

		goto sendpkt;	/* send anyway */
	}

	/* We don't have to do link-layer address resolution on a p2p link. */
	if ((ifp->if_flags & IFF_POINTOPOINT) != 0 &&
	    ln->ln_state < ND6_LLINFO_REACHABLE) {
		ln->ln_state = ND6_LLINFO_STALE;
		ln->ln_expire = time_second + nd6_gctimer;
	}

	/*
	 * The first time we send a packet to a neighbor whose entry is
	 * STALE, we have to change the state to DELAY and a sets a timer to
	 * expire in DELAY_FIRST_PROBE_TIME seconds to ensure do
	 * neighbor unreachability detection on expiration.
	 * (RFC 2461 7.3.3)
	 */
	if (ln->ln_state == ND6_LLINFO_STALE) {
		ln->ln_asked = 0;
		ln->ln_state = ND6_LLINFO_DELAY;
		ln->ln_expire = time_second + nd6_delay;
	}

	/*
	 * If the neighbor cache entry has a state other than INCOMPLETE
	 * (i.e. its link-layer address is already resolved), just
	 * send the packet.
	 */
	if (ln->ln_state > ND6_LLINFO_INCOMPLETE)
		goto sendpkt;

	/*
	 * There is a neighbor cache entry, but no ethernet address
	 * response yet.  Replace the held mbuf (if any) with this
	 * latest one.
	 * This code conforms to the rate-limiting rule described in Section
	 * 7.2.2 of RFC 2461, because the timer is set correctly after sending
	 * an NS below.
	 */
	if (ln->ln_state == ND6_LLINFO_NOSTATE)
		ln->ln_state = ND6_LLINFO_INCOMPLETE;
	if (ln->ln_hold)
		m_freem(ln->ln_hold);
	ln->ln_hold = m;
	if (ln->ln_expire) {
		if (ln->ln_asked < nd6_mmaxtries &&
		    ln->ln_expire < time_second) {
			ln->ln_asked++;
			ln->ln_expire = time_second +
				nd_ifinfo[ifp->if_index].retrans / 1000;
			nd6_ns_output(ifp, NULL, &dst->sin6_addr, ln, 0);
		}
	}
	return(0);
	
  sendpkt:
#if defined(__OpenBSD__) && defined(IPSEC)
	/*
	 * If the packet needs outgoing IPsec crypto processing and the
	 * interface doesn't support it, drop it.
	 */
	mtag = m_tag_find(m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
#endif /* IPSEC */

	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
#if defined(__OpenBSD__) && defined(IPSEC)
		if (mtag != NULL &&
		    (origifp->if_capabilities & IFCAP_IPSEC) == 0) {
			/* Tell IPsec to do its own crypto. */
			ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1));
			error = EACCES;
			goto bad;
		}
#endif /* IPSEC */
		return((*ifp->if_output)(origifp, m, (struct sockaddr *)dst,
					 rt));
	}
#if defined(__OpenBSD__) && defined(IPSEC)
	if (mtag != NULL &&
	    (ifp->if_capabilities & IFCAP_IPSEC) == 0) {
		/* Tell IPsec to do its own crypto. */
		ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1));
		error = EACCES;
		goto bad;
	}
#endif /* IPSEC */
	return((*ifp->if_output)(ifp, m, (struct sockaddr *)dst, rt));

  bad:
	if (m)
		m_freem(m);
	return (error);
}	
#undef senderr

int
nd6_need_cache(ifp)
	struct ifnet *ifp;
{
	/*
	 * XXX: we currently do not make neighbor cache on any interface
	 * other than ARCnet, Ethernet, FDDI and GIF.
	 *
	 * RFC2893 says:
	 * - unidirectional tunnels needs no ND
	 */
	switch (ifp->if_type) {
	case IFT_ARCNET:
	case IFT_ETHER:
	case IFT_FDDI:
	case IFT_IEEE1394:
#ifdef IFT_PROPVIRTUAL
	case IFT_PROPVIRTUAL:
#endif
#ifdef IFT_L2VLAN
	case IFT_L2VLAN:
#endif
#ifdef IFT_IEEE80211
	case IFT_IEEE80211:
#endif
	case IFT_GIF:		/* XXX need more cases? */
		return(1);
	default:
		return(0);
	}
}

int
nd6_storelladdr(ifp, rt, m, dst, desten)
	struct ifnet *ifp;
	struct rtentry *rt;
	struct mbuf *m;
	struct sockaddr *dst;
	u_char *desten;
{
	int i;
	struct sockaddr_dl *sdl;

	if (m->m_flags & M_MCAST) {
		switch (ifp->if_type) {
		case IFT_ETHER:
		case IFT_FDDI:
#ifdef IFT_PROPVIRTUAL
		case IFT_PROPVIRTUAL:
#endif
#ifdef IFT_L2VLAN
		case IFT_L2VLAN:
#endif
#ifdef IFT_IEEE80211
		case IFT_IEEE80211:
#endif
			ETHER_MAP_IPV6_MULTICAST(&SIN6(dst)->sin6_addr,
						 desten);
			return(1);
		case IFT_IEEE1394:
			/*
			 * netbsd can use if_broadcastaddr, but we don't do so
			 * to reduce # of ifdef.
			 */
			for (i = 0; i < ifp->if_addrlen; i++)
				desten[i] = ~0;
			return(1);
		case IFT_ARCNET:
			*desten = 0;
			return(1);
		default:
			m_freem(m);
			return(0);
		}
	}

	if (rt == NULL) {
		/* this could happen, if we could not allocate memory */
		m_freem(m);
		return(0);
	}
	if (rt->rt_gateway->sa_family != AF_LINK) {
		printf("nd6_storelladdr: something odd happens\n");
		m_freem(m);
		return(0);
	}
	sdl = SDL(rt->rt_gateway);
	if (sdl->sdl_alen == 0) {
		/* this should be impossible, but we bark here for debugging */
		printf("nd6_storelladdr: sdl_alen == 0, dst=%s, if=%s\n",
		       ip6_sprintf(&SIN6(dst)->sin6_addr), if_name(ifp));
		m_freem(m);
		return(0);
	}

	bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
	return(1);
}

#ifdef CYGPKG_NET_FREEBSD_SYSCTL
static int nd6_sysctl_drlist(SYSCTL_HANDLER_ARGS);
static int nd6_sysctl_prlist(SYSCTL_HANDLER_A