nd6_rtr.c

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

		    (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
		    ND6_IS_LLINFO_PROBREACH(ln)) {
			selected_dr = dr;
		}

		if (dr->installed && !installed_dr)
			installed_dr = dr;
		else if (dr->installed && installed_dr) {
			/* this should not happen.  warn for diagnosis. */
			log(LOG_ERR, "defrouter_select: more than one router"
			    " is installed\n");
		}
	}
	/*
	 * If none of the default routers was found to be reachable,
	 * round-robin the list regardless of preference.
	 * Otherwise, if we have an installed router, check if the selected
	 * (reachable) router should really be preferred to the installed one.
	 * We only prefer the new router when the old one is not reachable
	 * or when the new one has a really higher preference value.
	 */
	if (!selected_dr) {
		if (!installed_dr || !TAILQ_NEXT(installed_dr, dr_entry))
			selected_dr = TAILQ_FIRST(&nd_defrouter);
		else
 			selected_dr = TAILQ_NEXT(installed_dr, dr_entry);
	} else if (installed_dr &&
		   (rt = nd6_lookup(&installed_dr->rtaddr, 0,
				    installed_dr->ifp)) &&
		   (ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
		   ND6_IS_LLINFO_PROBREACH(ln) &&
		   rtpref(selected_dr) <= rtpref(installed_dr)) {
			selected_dr = installed_dr;
	}

	/*
	 * If the selected router is different than the installed one,
	 * remove the installed router and install the selected one.
	 * Note that the selected router is never NULL here.
	 */
	if (installed_dr != selected_dr) {
		if (installed_dr)
			defrouter_delreq(installed_dr);
		defrouter_addreq(selected_dr);
	}

	splx(s);
	return;
}

/* 
 * for default router selection
 * regards router-preference field as a 2-bit signed integer 
 */
static int
rtpref(struct nd_defrouter *dr)
{
#ifdef RTPREF
	switch (dr->flags & ND_RA_FLAG_RTPREF_MASK) {
	case ND_RA_FLAG_RTPREF_HIGH:
		return RTPREF_HIGH;
	case ND_RA_FLAG_RTPREF_MEDIUM:
	case ND_RA_FLAG_RTPREF_RSV:
		return RTPREF_MEDIUM;
	case ND_RA_FLAG_RTPREF_LOW:
		return RTPREF_LOW;
	default:
		/*
		 * This case should never happen.  If it did, it would mean a
		 * serious bug of kernel internal.  We thus always bark here.
		 * Or, can we even panic?
		 */
		log(LOG_ERR, "rtpref: impossible RA flag %x", dr->flags);
		return RTPREF_INVALID;
	}
	/* NOT REACH HERE */
#else
	return RTPREF_MEDIUM;
#endif
}

static struct nd_defrouter *
defrtrlist_update(new)
	struct nd_defrouter *new;
{
	struct nd_defrouter *dr, *n;
#ifdef __NetBSD__
	int s = splsoftnet();
#else
	int s = splnet();
#endif

	if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
		/* entry exists */
		if (new->rtlifetime == 0) {
			defrtrlist_del(dr);
			dr = NULL;
		} else {
			int oldpref = rtpref(dr);

			/* override */
			dr->flags = new->flags; /* xxx flag check */
			dr->rtlifetime = new->rtlifetime;
			dr->expire = new->expire;

			/* 
			 * If the preference does not change, there's no need
			 * to sort the entries.
			 */
			if (rtpref(new) == oldpref) {
				splx(s);
				return(dr);
			}

			/*
			 * preferred router may be changed, so relocate
			 * this router.
			 * XXX: calling TAILQ_REMOVE directly is a bad manner.
			 * However, since defrtrlist_del() has many side
			 * effects, we intentionally do so here.
			 * defrouter_select() below will handle routing
			 * changes later.
			 */
			TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
			n = dr;
			goto insert;
		}
		splx(s);
		return(dr);
	}

	/* entry does not exist */
	if (new->rtlifetime == 0) {
		splx(s);
		return(NULL);
	}

	n = (struct nd_defrouter *)malloc(sizeof(*n), M_IP6NDP, M_NOWAIT);
	if (n == NULL) {
		splx(s);
		return(NULL);
	}
	bzero(n, sizeof(*n));
	*n = *new;

insert:
	/*
	 * Insert the new router in the Default Router List;
	 * The Default Router List should be in the descending order
	 * of router-preferece.  Routers with the same preference are
	 * sorted in the arriving time order.
	 */

	/* insert at the end of the group */
	for (dr = TAILQ_FIRST(&nd_defrouter); dr;
	     dr = TAILQ_NEXT(dr, dr_entry)) {
		if (rtpref(n) > rtpref(dr))
			break;
	}
	if (dr)
		TAILQ_INSERT_BEFORE(dr, n, dr_entry);
	else
		TAILQ_INSERT_TAIL(&nd_defrouter, n, dr_entry);

	defrouter_select();

	splx(s);
		
	return(n);
}

static struct nd_pfxrouter *
pfxrtr_lookup(pr, dr)
	struct nd_prefix *pr;
	struct nd_defrouter *dr;
{
	struct nd_pfxrouter *search;
	
	for (search = pr->ndpr_advrtrs.lh_first; search; search = search->pfr_next) {
		if (search->router == dr)
			break;
	}

	return(search);
}

static void
pfxrtr_add(pr, dr)
	struct nd_prefix *pr;
	struct nd_defrouter *dr;
{
	struct nd_pfxrouter *new;

	new = (struct nd_pfxrouter *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
	if (new == NULL)
		return;
	bzero(new, sizeof(*new));
	new->router = dr;

	LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);

	pfxlist_onlink_check();
}

static void
pfxrtr_del(pfr)
	struct nd_pfxrouter *pfr;
{
	LIST_REMOVE(pfr, pfr_entry);
	free(pfr, M_IP6NDP);
}

struct nd_prefix *
nd6_prefix_lookup(pr)
	struct nd_prefix *pr;
{
	struct nd_prefix *search;

	for (search = nd_prefix.lh_first; search; search = search->ndpr_next) {
		if (pr->ndpr_ifp == search->ndpr_ifp &&
		    pr->ndpr_plen == search->ndpr_plen &&
		    in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
					 &search->ndpr_prefix.sin6_addr,
					 pr->ndpr_plen)
		    ) {
			break;
		}
	}

	return(search);
}

int
nd6_prelist_add(pr, dr, newp)
	struct nd_prefix *pr, **newp;
	struct nd_defrouter *dr;
{
	struct nd_prefix *new = NULL;
	int i, s;

	new = (struct nd_prefix *)malloc(sizeof(*new), M_IP6NDP, M_NOWAIT);
	if (new == NULL)
		return ENOMEM;
	bzero(new, sizeof(*new));
	*new = *pr;
	if (newp != NULL)
		*newp = new;

	/* initilization */
	LIST_INIT(&new->ndpr_advrtrs);
	in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
	/* make prefix in the canonical form */
	for (i = 0; i < 4; i++)
		new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
			new->ndpr_mask.s6_addr32[i];

#ifdef __NetBSD__
	s = splsoftnet();
#else
	s = splnet();
#endif
	/* link ndpr_entry to nd_prefix list */
	LIST_INSERT_HEAD(&nd_prefix, new, ndpr_entry);
	splx(s);

	/* ND_OPT_PI_FLAG_ONLINK processing */
	if (new->ndpr_raf_onlink) {
		int e;

		if ((e = nd6_prefix_onlink(new)) != 0) {
			nd6log((LOG_ERR, "nd6_prelist_add: failed to make "
			    "the prefix %s/%d on-link on %s (errno=%d)\n",
			    ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
			    pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
			/* proceed anyway. XXX: is it correct? */
		}
	}

	if (dr)
		pfxrtr_add(new, dr);

	return 0;
}

void
prelist_remove(pr)
	struct nd_prefix *pr;
{
	struct nd_pfxrouter *pfr, *next;
	int e, s;

	/* make sure to invalidate the prefix until it is really freed. */
	pr->ndpr_vltime = 0;
	pr->ndpr_pltime = 0;
#if 0
	/*
	 * Though these flags are now meaningless, we'd rather keep the value
	 * not to confuse users when executing "ndp -p".
	 */
	pr->ndpr_raf_onlink = 0;
	pr->ndpr_raf_auto = 0;
#endif
	if ((pr->ndpr_stateflags & NDPRF_ONLINK) != 0 &&
	    (e = nd6_prefix_offlink(pr)) != 0) {
		nd6log((LOG_ERR, "prelist_remove: failed to make %s/%d offlink "
		    "on %s, errno=%d\n",
		    ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
		    pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
		/* what should we do? */
	}

	if (pr->ndpr_refcnt > 0)
		return;		/* notice here? */

#ifdef __NetBSD__
	s = splsoftnet();
#else
	s = splnet();
#endif

	/* unlink ndpr_entry from nd_prefix list */
	LIST_REMOVE(pr, ndpr_entry);

	/* free list of routers that adversed the prefix */
	for (pfr = pr->ndpr_advrtrs.lh_first; pfr; pfr = next) {
		next = pfr->pfr_next;

		free(pfr, M_IP6NDP);
	}
	splx(s);

	free(pr, M_IP6NDP);

	pfxlist_onlink_check();
}

int
prelist_update(new, dr, m)
	struct nd_prefix *new;
	struct nd_defrouter *dr; /* may be NULL */
	struct mbuf *m;
{
	struct in6_ifaddr *ia6 = NULL, *ia6_match = NULL;
	struct ifaddr *ifa;
	struct ifnet *ifp = new->ndpr_ifp;
	struct nd_prefix *pr;
#ifdef __NetBSD__
	int s = splsoftnet();
#else
	int s = splnet();
#endif
	int error = 0;
	int newprefix = 0;
	int auth;
	struct in6_addrlifetime lt6_tmp;

	auth = 0;
	if (m) {
		/*
		 * Authenticity for NA consists authentication for
		 * both IP header and IP datagrams, doesn't it ?
		 */
#if defined(M_AUTHIPHDR) && defined(M_AUTHIPDGM)
		auth = (m->m_flags & M_AUTHIPHDR
		     && m->m_flags & M_AUTHIPDGM) ? 1 : 0;
#endif
	}

	if ((pr = nd6_prefix_lookup(new)) != NULL) {
		/*
		 * nd6_prefix_lookup() ensures that pr and new have the same
		 * prefix on a same interface.
		 */

		/*
		 * Update prefix information.  Note that the on-link (L) bit
		 * and the autonomous (A) bit should NOT be changed from 1
		 * to 0.
		 */
		if (new->ndpr_raf_onlink == 1)
			pr->ndpr_raf_onlink = 1;
		if (new->ndpr_raf_auto == 1)
			pr->ndpr_raf_auto = 1;
		if (new->ndpr_raf_onlink) {
			pr->ndpr_vltime = new->ndpr_vltime;
			pr->ndpr_pltime = new->ndpr_pltime;
			pr->ndpr_preferred = new->ndpr_preferred;
			pr->ndpr_expire = new->ndpr_expire;
			pr->ndpr_lastupdate = new->ndpr_lastupdate;
		}

		if (new->ndpr_raf_onlink &&
		    (pr->ndpr_stateflags & NDPRF_ONLINK) == 0) {
			int e;

			if ((e = nd6_prefix_onlink(pr)) != 0) {
				nd6log((LOG_ERR,
				    "prelist_update: failed to make "
				    "the prefix %s/%d on-link on %s "
				    "(errno=%d)\n",
				    ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
				    pr->ndpr_plen, if_name(pr->ndpr_ifp), e));
				/* proceed anyway. XXX: is it correct? */
			}
		}

		if (dr && pfxrtr_lookup(pr, dr) == NULL)
			pfxrtr_add(pr, dr);
	} else {
		struct nd_prefix *newpr = NULL;

		newprefix = 1;

		if (new->ndpr_vltime == 0)
			goto end;
		if (new->ndpr_raf_onlink == 0 && new->ndpr_raf_auto == 0)
			goto end;

		error = nd6_prelist_add(new, dr, &newpr);
		if (error != 0 || newpr == NULL) {
			nd6log((LOG_NOTICE, "prelist_update: "
			    "nd6_prelist_add failed for %s/%d on %s "
			    "errno=%d, returnpr=%p\n",
			    ip6_sprintf(&new->ndpr_prefix.sin6_addr),
					new->ndpr_plen, if_name(new->ndpr_ifp),
					error, newpr));
			goto end; /* we should just give up in this case. */
		}

		/*
		 * XXX: from the ND point of view, we can ignore a prefix
		 * with the on-link bit being zero.  However, we need a
		 * prefix structure for references from autoconfigured
		 * addresses.  Thus, we explicitly make sure that the prefix
		 * itself expires now.
		 */
		if (newpr->ndpr_raf_onlink == 0) {
			newpr->ndpr_vltime = 0;
			newpr->ndpr_pltime = 0;
			in6_init_prefix_ltimes(newpr);
		}

		pr = newpr;
	}

	/*
	 * Address autoconfiguration based on Section 5.5.3 of RFC 2462.
	 * Note that pr must be non NULL at this point.
	 */

	/* 5.5.3 (a). Ignore the prefix without the A bit set. */
	if (!new->ndpr_raf_auto)
		goto end;

	/*