zebra: add connected_check_ptp infrastructure

add a connected_check_ptp function which does the same as
connected_check, but takes an additional peer prefix argument.

also fix related prefixlen mixup in PtP addresses (the local part of a
PtP address always is /32, but previously the peer mask got copied.)

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>

3 files changed, 59 insertions, 9 deletions

diff --git a/zebra/connected.c b/zebra/connected.c
index 701314f246..1368a12289 100644
--- a/zebra/connected.c
+++ b/zebra/connected.c
@@ -100,8 +100,10 @@ static void connected_announce(struct interface *ifp, struct connected *ifc)
 }
 
 /* If same interface address is already exist... */
-struct connected *connected_check(struct interface *ifp, struct prefix *p)
+struct connected *connected_check(struct interface *ifp,
+				  union prefixconstptr pu)
 {
+	const struct prefix *p = pu.p;
 	struct connected *ifc;
 	struct listnode *node;
 
@@ -112,6 +114,33 @@ struct connected *connected_check(struct interface *ifp, struct prefix *p)
 	return NULL;
 }
 
+/* same, but with peer address */
+struct connected *connected_check_ptp(struct interface *ifp,
+				      union prefixconstptr pu,
+				      union prefixconstptr du)
+{
+	const struct prefix *p = pu.p;
+	const struct prefix *d = du.p;
+	struct connected *ifc;
+	struct listnode *node;
+
+	/* ignore broadcast addresses */
+	if (p->prefixlen != IPV4_MAX_PREFIXLEN)
+		d = NULL;
+
+	for (ALL_LIST_ELEMENTS_RO(ifp->connected, node, ifc)) {
+		if (!prefix_same(ifc->address, p))
+			continue;
+		if (!CONNECTED_PEER(ifc) && !d)
+			return ifc;
+		if (CONNECTED_PEER(ifc) && d
+		    && prefix_same(ifc->destination, d))
+			return ifc;
+	}
+
+	return NULL;
+}
+
 /* Check if two ifc's describe the same address in the same state */
 static int connected_same(struct connected *ifc1, struct connected *ifc2)
 {
@@ -145,7 +174,8 @@ static void connected_update(struct interface *ifp, struct connected *ifc)
 	struct connected *current;
 
 	/* Check same connected route. */
-	if ((current = connected_check(ifp, (struct prefix *)ifc->address))) {
+	current = connected_check_ptp(ifp, ifc->address, ifc->destination);
+	if (current) {
 		if (CHECK_FLAG(current->conf, ZEBRA_IFC_CONFIGURED))
 			SET_FLAG(ifc->conf, ZEBRA_IFC_CONFIGURED);
 
@@ -238,7 +268,8 @@ void connected_add_ipv4(struct interface *ifp, int flags, struct in_addr *addr,
 	p = prefix_ipv4_new();
 	p->family = AF_INET;
 	p->prefix = *addr;
-	p->prefixlen = prefixlen;
+	p->prefixlen = CHECK_FLAG(flags, ZEBRA_IFA_PEER) ? IPV4_MAX_PREFIXLEN
+							 : prefixlen;
 	ifc->address = (struct prefix *)p;
 
 	/* If there is broadcast or peer address. */
@@ -350,15 +381,25 @@ void connected_delete_ipv4(struct interface *ifp, int flags,
 			   struct in_addr *addr, u_char prefixlen,
 			   struct in_addr *broad)
 {
-	struct prefix_ipv4 p;
+	struct prefix_ipv4 p, d;
 	struct connected *ifc;
 
 	memset(&p, 0, sizeof(struct prefix_ipv4));
 	p.family = AF_INET;
 	p.prefix = *addr;
-	p.prefixlen = prefixlen;
+	p.prefixlen = CHECK_FLAG(flags, ZEBRA_IFA_PEER) ? IPV4_MAX_PREFIXLEN
+							: prefixlen;
+
+	if (broad) {
+		memset(&d, 0, sizeof(struct prefix_ipv4));
+		d.family = AF_INET;
+		d.prefix = *broad;
+		d.prefixlen = prefixlen;
+		ifc = connected_check_ptp(ifp, (struct prefix *)&p,
+					  (struct prefix *)&d);
+	} else
+		ifc = connected_check_ptp(ifp, (struct prefix *)&p, NULL);
 
-	ifc = connected_check(ifp, (struct prefix *)&p);
 	if (!ifc)
 		return;
 
diff --git a/zebra/connected.h b/zebra/connected.h
index eaf79fe9aa..b67442fa3b 100644
--- a/zebra/connected.h
+++ b/zebra/connected.h
@@ -23,7 +23,10 @@
 #define _ZEBRA_CONNECTED_H
 
 extern struct connected *connected_check(struct interface *ifp,
-					 struct prefix *p);
+					 union prefixconstptr p);
+extern struct connected *connected_check_ptp(struct interface *ifp,
+					     union prefixconstptr p,
+					     union prefixconstptr d);
 
 extern void connected_add_ipv4(struct interface *ifp, int flags,
 			       struct in_addr *addr, u_char prefixlen,
diff --git a/zebra/interface.c b/zebra/interface.c
index c17e408ea0..9b4af1786e 100644
--- a/zebra/interface.c
+++ b/zebra/interface.c
@@ -242,7 +242,7 @@ int if_subnet_add(struct interface *ifp, struct connected *ifc)
 	/* Get address derived subnet node and associated address list, while
 	   marking
 	   address secondary attribute appropriately. */
-	cp = *ifc->address;
+	cp = *CONNECTED_PREFIX(ifc);
 	apply_mask(&cp);
 	rn = route_node_get(zebra_if->ipv4_subnets, &cp);
 
@@ -267,12 +267,16 @@ int if_subnet_delete(struct interface *ifp, struct connected *ifc)
 	struct route_node *rn;
 	struct zebra_if *zebra_if;
 	struct list *addr_list;
+	struct prefix cp;
 
 	assert(ifp && ifp->info && ifc);
 	zebra_if = ifp->info;
 
+	cp = *CONNECTED_PREFIX(ifc);
+	apply_mask(&cp);
+
 	/* Get address derived subnet node. */
-	rn = route_node_lookup(zebra_if->ipv4_subnets, ifc->address);
+	rn = route_node_lookup(zebra_if->ipv4_subnets, &cp);
 	if (!(rn && rn->info)) {
 		zlog_warn(
 			"Trying to remove an address from an unknown subnet."
@@ -966,6 +970,8 @@ static void connected_dump_vty(struct vty *vty, struct connected *connected)
 		vty_out(vty,
 			(CONNECTED_PEER(connected) ? " peer " : " broadcast "));
 		prefix_vty_out(vty, connected->destination);
+		if (CONNECTED_PEER(connected))
+			vty_out(vty, "/%d", connected->destination->prefixlen);
 	}
 
 	if (CHECK_FLAG(connected->flags, ZEBRA_IFA_SECONDARY))