nd6.c

eCos操作系统源码

	struct in6_ifaddr *ia6, *nia6;
	struct in6_addrlifetime *lt6;
	
#ifdef __NetBSD__
	s = splsoftnet();
#else
	s = splnet();
#endif
#if defined(__NetBSD__) || (defined(__FreeBSD__) && __FreeBSD__ >= 3)
	callout_reset(&nd6_timer_ch, nd6_prune * hz,
	    nd6_timer, NULL);
#elif defined(__OpenBSD__)
	timeout_set(&nd6_timer_ch, nd6_timer, NULL);
	timeout_add(&nd6_timer_ch, nd6_prune * hz);
#else
	timeout(nd6_timer, (caddr_t)0, nd6_prune * hz);
#endif

	ln = llinfo_nd6.ln_next;
	while (ln && ln != &llinfo_nd6) {
		struct rtentry *rt;
		struct sockaddr_in6 *dst;
		struct llinfo_nd6 *next = ln->ln_next;
		/* XXX: used for the DELAY case only: */
		struct nd_ifinfo *ndi = NULL;

		if ((rt = ln->ln_rt) == NULL) {
			ln = next;
			continue;
		}
		if ((ifp = rt->rt_ifp) == NULL) {
			ln = next;
			continue;
		}
		ndi = &nd_ifinfo[ifp->if_index];
		dst = (struct sockaddr_in6 *)rt_key(rt);

		if (ln->ln_expire > time_second) {
			ln = next;
			continue;
		}

		/* sanity check */
		if (!rt)
			panic("rt=0 in nd6_timer(ln=%p)\n", ln);
		if (rt->rt_llinfo && (struct llinfo_nd6 *)rt->rt_llinfo != ln)
			panic("rt_llinfo(%p) is not equal to ln(%p)\n",
			      rt->rt_llinfo, ln);
		if (!dst)
			panic("dst=0 in nd6_timer(ln=%p)\n", ln);

		switch (ln->ln_state) {
		case ND6_LLINFO_INCOMPLETE:
			if (ln->ln_asked < nd6_mmaxtries) {
				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);
			} else {
				struct mbuf *m = ln->ln_hold;
				if (m) {
					struct ip6_hdr *ip6_in;
					struct sockaddr_in6 sin6_in;
					int64_t szoneid, dzoneid;

					/*
					 * Fake rcvif to make the ICMP error
					 * more helpful in diagnosing for the
					 * receiver.
					 * XXX: should we consider
					 * older rcvif?
					 */
					m->m_pkthdr.rcvif = rt->rt_ifp;

					/*
					 * XXX: for scoped addresses, we should
					 * disambiguate the zone.  We should
					 * perhaps hang sockaddr_in6 as aux
					 * data in the mbuf.
					 */
					ip6_in = mtod(m, struct ip6_hdr *);
					szoneid = in6_addr2zoneid(rt->rt_ifp,
								  &ip6_in->ip6_src);
					dzoneid = in6_addr2zoneid(rt->rt_ifp,
								  &ip6_in->ip6_dst);
					if (szoneid < 0 || dzoneid < 0) {
						/* impossible... */
						m_freem(m);
					} else {
						bzero(&sin6_in,
						      sizeof(sin6_in));
						sin6_in.sin6_addr = ip6_in->ip6_src;
						sin6_in.sin6_scope_id = szoneid;
						in6_embedscope(&ip6_in->ip6_src,
							       &sin6_in);
						bzero(&sin6_in,
						      sizeof(sin6_in));
						sin6_in.sin6_addr = ip6_in->ip6_dst;
						sin6_in.sin6_scope_id = dzoneid;
						in6_embedscope(&ip6_in->ip6_dst,
							       &sin6_in);
						icmp6_error(m,
							    ICMP6_DST_UNREACH,
							    ICMP6_DST_UNREACH_ADDR, 0);
					}
					ln->ln_hold = NULL;
				}
				next = nd6_free(rt, 0);
			}
			break;
		case ND6_LLINFO_REACHABLE:
			if (ln->ln_expire) {
				ln->ln_state = ND6_LLINFO_STALE;
				ln->ln_expire = time_second + nd6_gctimer;
			}
			break;

		case ND6_LLINFO_STALE:
			/* Garbage Collection(RFC 2461 5.3) */
			if (ln->ln_expire)
				next = nd6_free(rt, 1);
			break;

		case ND6_LLINFO_DELAY:
			if (ndi && (ndi->flags & ND6_IFF_PERFORMNUD) != 0) {
				/* We need NUD */
				ln->ln_asked = 1;
				ln->ln_state = ND6_LLINFO_PROBE;
				ln->ln_expire = time_second +
					ndi->retrans / 1000;
				nd6_ns_output(ifp, &dst->sin6_addr,
					      &dst->sin6_addr,
					      ln, 0);
			} else {
				ln->ln_state = ND6_LLINFO_STALE; /* XXX */
				ln->ln_expire = time_second + nd6_gctimer;
			}
			break;
		case ND6_LLINFO_PROBE:
			if (ln->ln_asked < nd6_umaxtries) {
				ln->ln_asked++;
				ln->ln_expire = time_second +
					nd_ifinfo[ifp->if_index].retrans / 1000;
				nd6_ns_output(ifp, &dst->sin6_addr,
					       &dst->sin6_addr, ln, 0);
			} else {
				next = nd6_free(rt, 0);
			}
			break;
		}
		ln = next;
	}
	
	/* expire default router list */
	dr = TAILQ_FIRST(&nd_defrouter);
	while (dr) {
		if (dr->expire && dr->expire < time_second) {
			struct nd_defrouter *t;
			t = TAILQ_NEXT(dr, dr_entry);
			defrtrlist_del(dr);
			dr = t;
		} else {
			dr = TAILQ_NEXT(dr, dr_entry);
		}
	}

	/*
	 * expire interface addresses.
	 * in the past the loop was inside prefix expiry processing.
	 * However, from a stricter speci-confrmance standpoint, we should
	 * rather separate address lifetimes and prefix lifetimes.
	 */
  addrloop:
	for (ia6 = in6_ifaddr; ia6; ia6 = nia6) {
		nia6 = ia6->ia_next;
		/* check address lifetime */
		lt6 = &ia6->ia6_lifetime;
		if (IFA6_IS_INVALID(ia6)) {
			int regen = 0;

			/*
			 * If the expiring address is temporary, try
			 * regenerating a new one.  This would be useful when
			 * we suspended a laptop PC, then turned it on after a
			 * period that could invalidate all temporary
			 * addresses.  Although we may have to restart the
			 * loop (see below), it must be after purging the
			 * address.  Otherwise, we'd see an infinite loop of
			 * regeneration. 
			 */
			if (ip6_use_tempaddr &&
			    (ia6->ia6_flags & IN6_IFF_TEMPORARY) != 0) {
				if (regen_tmpaddr(ia6) == 0)
					regen = 1;
			}

			in6_purgeaddr(&ia6->ia_ifa);

			if (regen)
				goto addrloop; /* XXX: see below */
		}
		if (IFA6_IS_DEPRECATED(ia6)) {
			int oldflags = ia6->ia6_flags;

			ia6->ia6_flags |= IN6_IFF_DEPRECATED;

			/*
			 * If a temporary address has just become deprecated,
			 * regenerate a new one if possible.
			 */
			if (ip6_use_tempaddr &&
			    (ia6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
			    (oldflags & IN6_IFF_DEPRECATED) == 0) {

				if (regen_tmpaddr(ia6) == 0) {
					/*
					 * A new temporary address is
					 * generated.
					 * XXX: this means the address chain
					 * has changed while we are still in
					 * the loop.  Although the change
					 * would not cause disaster (because
					 * it's not a deletion, but an
					 * addition,) we'd rather restart the
					 * loop just for safety.  Or does this 
					 * significantly reduce performance??
					 */
					goto addrloop;
				}
			}
		} else {
			/*
			 * A new RA might have made a deprecated address
			 * preferred.
			 */
			ia6->ia6_flags &= ~IN6_IFF_DEPRECATED;
		}
	}

	/* expire prefix list */
	pr = nd_prefix.lh_first;
	while (pr) {
		/*
		 * check prefix lifetime.
		 * since pltime is just for autoconf, pltime processing for
		 * prefix is not necessary.
		 */
		if (pr->ndpr_vltime != ND6_INFINITE_LIFETIME &&
		    time_second - pr->ndpr_lastupdate > pr->ndpr_vltime) {
			struct nd_prefix *t;
			t = pr->ndpr_next;

			/*
			 * address expiration and prefix expiration are
			 * separate.  NEVER perform in6_purgeaddr here.
			 */

			prelist_remove(pr);
			pr = t;
		} else
			pr = pr->ndpr_next;
	}
	splx(s);
}

static int
regen_tmpaddr(ia6)
	struct in6_ifaddr *ia6; /* deprecated/invalidated temporary address */
{
	struct ifaddr *ifa;
	struct ifnet *ifp;
	struct in6_ifaddr *public_ifa6 = NULL;

	ifp = ia6->ia_ifa.ifa_ifp;
#if defined(__bsdi__) || (defined(__FreeBSD__) && __FreeBSD__ < 3)
	for (ifa = ifp->if_addrlist; ifa; ifa = ifa->ifa_next)
#else
	for (ifa = ifp->if_addrlist.tqh_first; ifa;
	     ifa = ifa->ifa_list.tqe_next)
#endif
	{
		struct in6_ifaddr *it6;

		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;

		it6 = (struct in6_ifaddr *)ifa;

		/* ignore no autoconf addresses. */
		if ((it6->ia6_flags & IN6_IFF_AUTOCONF) == 0)
			continue;

		/* ignore autoconf addresses with different prefixes. */
		if (it6->ia6_ndpr == NULL || it6->ia6_ndpr != ia6->ia6_ndpr)
			continue;

		/*
		 * Now we are looking at an autoconf address with the same
		 * prefix as ours.  If the address is temporary and is still
		 * preferred, do not create another one.  It would be rare, but
		 * could happen, for example, when we resume a laptop PC after
		 * a long period.
		 */
		if ((it6->ia6_flags & IN6_IFF_TEMPORARY) != 0 &&
		    !IFA6_IS_DEPRECATED(it6)) {
			public_ifa6 = NULL;
			break;
		}

		/*
		 * This is a public autoconf address that has the same prefix
		 * as ours.  If it is preferred, keep it.  We can't break the
		 * loop here, because there may be a still-preferred temporary
		 * address with the prefix.
		 */
		if (!IFA6_IS_DEPRECATED(it6))
		    public_ifa6 = it6;
	}

	if (public_ifa6 != NULL) {
		int e;

		if ((e = in6_tmpifadd(public_ifa6, 0)) != 0) {
			log(LOG_NOTICE, "regen_tmpaddr: failed to create a new"
			    " tmp addr,errno=%d\n", e);
			return(-1);
		}
		return(0);
	}

	return(-1);
}

/*
 * Nuke neighbor cache/prefix/default router management table, right before
 * ifp goes away.
 */
void
nd6_purge(ifp)
	struct ifnet *ifp;
{
	struct llinfo_nd6 *ln, *nln;
	struct nd_defrouter *dr, *ndr;
	struct nd_prefix *pr, *npr;

	/*
	 * Nuke default router list entries toward ifp.
	 * We defer removal of default router list entries that is installed
	 * in the routing table, in order to keep additional side effects as
	 * small as possible.
	 */
	for (dr = TAILQ_FIRST(&nd_defrouter); dr; dr = ndr) {
		ndr = TAILQ_NEXT(dr, dr_entry);
		if (dr->installed)
			continue;

		if (dr->ifp == ifp)
			defrtrlist_del(dr);
	}
	for (dr = TAILQ_FIRST(&nd_defrouter); dr; dr = ndr) {
		ndr = TAILQ_NEXT(dr, dr_entry);
		if (!dr->installed)
			continue;

		if (dr->ifp == ifp)
			defrtrlist_del(dr);
	}

	/* Nuke prefix list entries toward ifp */
	for (pr = nd_prefix.lh_first; pr; pr = npr) {
		npr = pr->ndpr_next;
		if (pr->ndpr_ifp == ifp) {
			/*
			 * Previously, pr->ndpr_addr is removed as well,
			 * but I strongly believe we don't have to do it.
			 * nd6_purge() is only called from in6_ifdetach(),
			 * which removes all the associated interface addresses
			 * by itself.
			 * ([e-mail] 20010129)
			 */
			prelist_remove(pr);
		}
	}

	/* cancel default outgoing interface setting */
	if (nd6_defifindex == ifp->if_index)
		nd6_setdefaultiface(0);

	if (!ip6_forwarding && ip6_accept_rtadv) { /* XXX: too restrictive? */
		/* refresh default router list */
		defrouter_select();
	}

	/*
	 * Nuke neighbor cache entries for the ifp.
	 * Note that rt->rt_ifp may not be the same as ifp,
	 * due to KAME goto ours hack.  See RTM_RESOLVE case in
	 * nd6_rtrequest(), and ip6_input().
	 */
	ln = llinfo_nd6.ln_next;
	while (ln && ln != &llinfo_nd6) {
		struct rtentry *rt;
		struct sockaddr_dl *sdl;

		nln = ln->ln_next;
		rt = ln->ln_rt;
		if (rt && rt->rt_gateway &&
		    rt->rt_gateway->sa_family == AF_LINK) {
			sdl = (struct sockaddr_dl *)rt->rt_gateway;
			if (sdl->sdl_index == ifp->if_index)
				nln = nd6_free(rt, 0);
		}
		ln = nln;
	}
}

struct rtentry *
nd6_lookup(addr6, create, ifp)
	struct in6_addr *addr6;
	int create;
	struct ifnet *ifp;
{
	struct rtentry *rt;
	struct sockaddr_in6 sin6;
#ifdef SCOPEDROUTING
	int64_t zoneid;
#endif

	bzero(&sin6, sizeof(sin6));
	sin6.sin6_len = sizeof(struct sockaddr_in6);
	sin6.sin6_family = AF_INET6;
	sin6.sin6_addr = *addr6;
#ifdef SCOPEDROUTING
	if ((zoneid = in6_addr2zoneid(ifp, addr6)) < 0)
		return(NULL);
	sin6.sin6_scope_id = zoneid;
#endif
	rt = rtalloc1((struct sockaddr *)&sin6, create
#ifdef __FreeBSD__
		      , 0UL
#endif /* __FreeBSD__ */
		      );
	if (rt && (rt->rt_flags & RTF_LLINFO) == 0) {
		/*
		 * This is the case for the default route.
		 * If we want to create a neighbor cache for the address, we
		 * should free the route for the destination and allocate an
		 * interface route.
		 */
		if (create) {
			RTFREE(rt);
			rt = 0;
		}
	}
	if (!rt) {
		if (create && ifp) {
			int e;

			/*
			 * If no route is available and create is set,
			 * we allocate a host route for the destination
			 * and treat it like an interface route.
			 * This hack is necessary for a neighbor which can't
			 * be covered by our own prefix.
			 */
			struct ifaddr *ifa =
				ifaof_ifpforaddr((struct sockaddr *)&sin6, ifp);
			if (ifa == NULL)
				return(NULL);

			/*
			 * Create a new route.  RTF_LLINFO is necessary
			 * to create a Neighbor Cache entry for the
			 * destination in nd6_rtrequest which will be
			 * called in rtrequest via ifa->ifa_rtrequest.
			 */
			if ((e = rtrequest(RTM_ADD, (struct sockaddr *)&sin6,
					   ifa->ifa_addr,
					   (struct sockaddr *)&all1_sa,
					   (ifa->ifa_flags |
					    RTF_HOST | RTF_LLINFO) &
					   ~RTF_CLONING,
					   &rt)) != 0) {
#if 0
				log(LOG_ERR,
				    "nd6_lookup: failed to add route for a "
				    "neighbor(%s), errno=%d\n",
				    ip6_sprintf(addr6), e);
#endif
				return(NULL);
			}
			if (rt == NULL)
				return(NULL);
			if (rt->rt_llinfo) {
				struct llinfo_nd6 *ln =
					(struct llinfo_nd6 *)rt->rt_llinfo;
				ln->ln_state = ND6_LLINFO_NOSTATE;
			}