As a first step towards SPF tree calculation, prepare for proper

next-hop calculation.

In OSPFv3, next-hop IP addresses are always link-local.
The kernel will want to know which interface the link-local
address belongs to, so we need an ifindex in struct v_nexthop
in addition to the IP address.

Because we cannot determine a link-local next hop IP address
for transit networks, only the outgoing interface will be recorded.

Update calc_nexthop_add() according to the above.

Also add new helpers calc_nexthop_lladdr() and calc_nexthop_transit_nbr(),
to figure out link-local addresses of nexthop neighbours.

ok claudio@

3 files changed, 73 insertions, 11 deletions

diff --git a/usr.sbin/ospf6d/rde.c b/usr.sbin/ospf6d/rde.c
index c16e46aa1ae..bb04bb77a1e 100644
--- a/usr.sbin/ospf6d/rde.c
+++ b/usr.sbin/ospf6d/rde.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde.c,v 1.26 2009/03/12 01:21:49 stsp Exp $ */
+/*	$OpenBSD: rde.c,v 1.27 2009/03/29 21:42:30 stsp Exp $ */
 
 /*
  * Copyright (c) 2004, 2005 Claudio Jeker <claudio@openbsd.org>
@@ -49,7 +49,6 @@ void		 rde_send_summary(pid_t);
 void		 rde_send_summary_area(struct area *, pid_t);
 void		 rde_nbr_init(u_int32_t);
 void		 rde_nbr_free(void);
-struct rde_nbr	*rde_nbr_find(u_int32_t);
 struct rde_nbr	*rde_nbr_new(u_int32_t, struct rde_nbr *);
 void		 rde_nbr_del(struct rde_nbr *);
 
diff --git a/usr.sbin/ospf6d/rde.h b/usr.sbin/ospf6d/rde.h
index d3ef2ef43ff..8d2f2820c60 100644
--- a/usr.sbin/ospf6d/rde.h
+++ b/usr.sbin/ospf6d/rde.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde.h,v 1.16 2009/03/29 19:28:10 stsp Exp $ */
+/*	$OpenBSD: rde.h,v 1.17 2009/03/29 21:42:30 stsp Exp $ */
 
 /*
  * Copyright (c) 2004, 2005 Esben Norby <norby@openbsd.org>
@@ -30,6 +30,7 @@ struct v_nexthop {
 	TAILQ_ENTRY(v_nexthop)	 entry;
 	struct vertex		*prev;
 	struct in6_addr		 nexthop;
+	u_int32_t		 ifindex;
 };
 
 TAILQ_HEAD(v_nexthead, v_nexthop);
@@ -130,6 +131,7 @@ void		 rde_send_delete_kroute(struct rt_node *);
 void		 rde_nbr_del(struct rde_nbr *);
 int		 rde_nbr_loading(struct area *);
 struct rde_nbr	*rde_nbr_self(struct area *);
+struct rde_nbr	*rde_nbr_find(u_int32_t);
 void		 rde_summary_update(struct rt_node *, struct area *);
 
 /* rde_lsdb.c */
diff --git a/usr.sbin/ospf6d/rde_spf.c b/usr.sbin/ospf6d/rde_spf.c
index 2640bc093db..7e5fd431e33 100644
--- a/usr.sbin/ospf6d/rde_spf.c
+++ b/usr.sbin/ospf6d/rde_spf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_spf.c,v 1.10 2009/03/29 19:34:23 stsp Exp $ */
+/*	$OpenBSD: rde_spf.c,v 1.11 2009/03/29 21:42:30 stsp Exp $ */
 
 /*
  * Copyright (c) 2005 Esben Norby <norby@openbsd.org>
@@ -37,7 +37,11 @@ RB_GENERATE(rt_tree, rt_node, entry, rt_compare)
 struct vertex			*spf_root = NULL;
 
 void		 calc_nexthop_clear(struct vertex *);
-void		 calc_nexthop_add(struct vertex *, struct vertex *, u_int32_t);
+void		 calc_nexthop_add(struct vertex *, struct vertex *,
+		     const struct in6_addr *, u_int32_t);
+struct in6_addr	*calc_nexthop_lladdr(struct vertex *, struct lsa_rtr_link *);
+void		 calc_nexthop_transit_nbr(struct vertex *, struct vertex *,
+		     u_int32_t ifindex);
 void		 calc_nexthop(struct vertex *, struct vertex *);
 void		 rt_nexthop_clear(struct rt_node *);
 void		 rt_nexthop_add(struct rt_node *, struct v_nexthead *,
@@ -374,23 +378,80 @@ calc_nexthop_clear(struct vertex *v)
 }
 
 void
-calc_nexthop_add(struct vertex *dst, struct vertex *parent, u_int32_t nexthop)
+calc_nexthop_add(struct vertex *dst, struct vertex *parent,
+	const struct in6_addr *nexthop, u_int32_t ifindex)
 {
 	struct v_nexthop	*vn;
 
-	if (nexthop == 0)
-		/* invalid nexthop, skip it */
-		return;
-
 	if ((vn = calloc(1, sizeof(*vn))) == NULL)
 		fatal("calc_nexthop_add");
 
 	vn->prev = parent;
-	/* XXX  vn->nexthop.s_addr = nexthop; */
+	if (nexthop)
+		vn->nexthop = *nexthop;
+	vn->ifindex = ifindex;
 
 	TAILQ_INSERT_TAIL(&dst->nexthop, vn, entry);
 }
 
+struct in6_addr *
+calc_nexthop_lladdr(struct vertex *dst, struct lsa_rtr_link *rtr_link)
+{
+	struct iface	*iface;
+	struct vertex	*link;
+	struct rde_nbr	*nbr;
+
+	/* Find outgoing interface, we need its LSA tree */
+	LIST_FOREACH(iface, &dst->area->iface_list, entry) {
+		if (ntohl(rtr_link->iface_id) == iface->ifindex)
+			break;
+	}
+	if (!iface) {
+		warnx("calc_nexthop_lladdr: no interface found for ifindex");
+		return (NULL);
+	}
+
+	/* Determine neighbor's link-local address.
+	 * Try to get it from link LSA first. */
+	link = lsa_find_tree(&iface->lsa_tree,
+		htons(LSA_TYPE_LINK), rtr_link->nbr_iface_id,
+		htonl(dst->adv_rtr));
+	if (link)
+		return &link->lsa->data.link.lladdr;
+
+	/* Not found, so fall back to source address
+	 * advertised in hello packet. */
+	if ((nbr = rde_nbr_find(dst->peerid)) == NULL)
+		fatalx("next hop is not a neighbor");
+	return &nbr->addr;
+}
+
+void
+calc_nexthop_transit_nbr(struct vertex *dst, struct vertex *parent,
+    u_int32_t ifindex)
+{
+	struct lsa_rtr_link	*rtr_link;
+	unsigned int		 i;
+	struct in6_addr		*lladdr;
+
+	if (dst->type != LSA_TYPE_ROUTER)
+		fatalx("calc_nexthop_transit_nbr: dst is not a router");
+	if (parent->type != LSA_TYPE_NETWORK)
+		fatalx("calc_nexthop_transit_nbr: parent is not a network");
+
+	/* dst is a neighbor on a directly attached transit network.
+	 * Figure out dst's link local address and add it as nexthop. */
+	for (i = 0; i < lsa_num_links(dst); i++) {
+		rtr_link = get_rtr_link(dst, i);
+		if (rtr_link->type == LINK_TYPE_TRANSIT_NET &&
+		    rtr_link->nbr_rtr_id == parent->lsa->hdr.adv_rtr &&
+		    rtr_link->nbr_iface_id == parent->lsa->hdr.ls_id) {
+			lladdr = calc_nexthop_lladdr(dst, rtr_link);
+			calc_nexthop_add(dst, parent, lladdr, ifindex);
+		}
+	}
+}
+
 void
 calc_nexthop(struct vertex *dst, struct vertex *parent)
 {