*: clean up ifp-by-local-address function(s)

Most users of if_lookup_address_exact only cared about whether the
address is any local address.  Split that off into a separate function.

For the users that actually need the ifp - which I'm about to add a few
of - change it to prefer returning interfaces that are UP.

(Function name changed due to slight change in behavior re. UP state, to
avoid possible bugs from this change.)

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

lib/if.c

@@ -455,36 +455,51 @@ static struct interface *if_lookup_by_index_all_vrf(ifindex_t ifindex)
 	return NULL;
 }
 
-/* Lookup interface by IP address. */
-struct interface *if_lookup_exact_address(const void *src, int family,
+/* Lookup interface by IP address.
+ *
+ * supersedes if_lookup_exact_address(), which didn't care about up/down
+ * state.  but all users we have either only care if the address is local
+ * (=> use if_address_is_local() please), or care about UP interfaces before
+ * anything else
+ *
+ * to accept only UP interfaces, check if_is_up() on the returned ifp.
+ */
+struct interface *if_lookup_address_local(const void *src, int family,
 					  vrf_id_t vrf_id)
 {
 	struct vrf *vrf = vrf_lookup_by_id(vrf_id);
 	struct listnode *cnode;
-	struct interface *ifp;
+	struct interface *ifp, *best_down = NULL;
 	struct prefix *p;
 	struct connected *c;
 
+	if (family != AF_INET && family != AF_INET6)
+		return NULL;
+
 	FOR_ALL_INTERFACES (vrf, ifp) {
 		for (ALL_LIST_ELEMENTS_RO(ifp->connected, cnode, c)) {
 			p = c->address;
 
-			if (p && (p->family == family)) {
-				if (family == AF_INET) {
-					if (IPV4_ADDR_SAME(
-						    &p->u.prefix4,
+			if (!p || p->family != family)
+				continue;
+
+			if (family == AF_INET) {
+				if (!IPV4_ADDR_SAME(&p->u.prefix4,
 						    (struct in_addr *)src))
-						return ifp;
-				} else if (family == AF_INET6) {
-					if (IPV6_ADDR_SAME(
-						    &p->u.prefix6,
+					continue;
+			} else if (family == AF_INET6) {
+				if (!IPV6_ADDR_SAME(&p->u.prefix6,
 						    (struct in6_addr *)src))
-						return ifp;
-				}
+					continue;
 			}
+
+			if (if_is_up(ifp))
+				return ifp;
+			if (!best_down)
+				best_down = ifp;
 		}
 	}
-	return NULL;
+	return best_down;
 }
 
 /* Lookup interface by IP address. */

lib/if.h

@@ -511,7 +511,7 @@ extern void if_update_to_new_vrf(struct interface *, vrf_id_t vrf_id);
 extern struct interface *if_lookup_by_index(ifindex_t, vrf_id_t vrf_id);
 extern struct interface *if_vrf_lookup_by_index_next(ifindex_t ifindex,
 						     vrf_id_t vrf_id);
-extern struct interface *if_lookup_exact_address(const void *matchaddr,
+extern struct interface *if_lookup_address_local(const void *matchaddr,
 						 int family, vrf_id_t vrf_id);
 extern struct connected *if_lookup_address(const void *matchaddr, int family,
 					   vrf_id_t vrf_id);
@@ -520,6 +520,12 @@ extern struct interface *if_lookup_prefix(const struct prefix *prefix,
 size_t if_lookup_by_hwaddr(const uint8_t *hw_addr, size_t addrsz,
 			   struct interface ***result, vrf_id_t vrf_id);
 
+static inline bool if_address_is_local(const void *matchaddr, int family,
+				       vrf_id_t vrf_id)
+{
+	return if_lookup_address_local(matchaddr, family, vrf_id) != NULL;
+}
+
 struct vrf;
 extern struct interface *if_lookup_by_name_vrf(const char *name, struct vrf *vrf);
 extern struct interface *if_lookup_by_name(const char *ifname, vrf_id_t vrf_id);

pimd/pim_bsm.c

@@ -1323,8 +1323,8 @@ int pim_bsm_process(struct interface *ifp, struct ip *ip_hdr, uint8_t *buf,
 				return -1;
 			}
 		}
-	} else if (if_lookup_exact_address(&ip_hdr->ip_dst, AF_INET,
-					   pim->vrf->vrf_id)) {
+	} else if (if_address_is_local(&ip_hdr->ip_dst, AF_INET,
+				       pim->vrf->vrf_id)) {
 		/* Unicast BSM received - if ucast bsm not enabled on
 		 * the interface, drop it
 		 */

pimd/pim_igmp.c

@@ -324,7 +324,7 @@ static int igmp_recv_query(struct igmp_sock *igmp, int query_version,
 		return 0;
 	}
 
-	if (if_lookup_exact_address(&from, AF_INET, ifp->vrf_id)) {
+	if (if_address_is_local(&from, AF_INET, ifp->vrf_id)) {
 		if (PIM_DEBUG_IGMP_PACKETS)
 			zlog_debug("Recv IGMP query on interface: %s from ourself %s",
 				   ifp->name, from_str);

pimd/pim_igmp_mtrace.c

@@ -596,8 +596,8 @@ int igmp_mtrace_recv_qry_req(struct igmp_sock *igmp, struct ip *ip_hdr,
 	 * if applicable
 	 */
 	if (!IPV4_CLASS_DE(ntohl(ip_hdr->ip_dst.s_addr)))
-		if (!if_lookup_exact_address(&ip_hdr->ip_dst, AF_INET,
-					     pim->vrf->vrf_id))
+		if (!if_address_is_local(&ip_hdr->ip_dst, AF_INET,
+					 pim->vrf->vrf_id))
 			return mtrace_forward_packet(pim, ip_hdr);
 
 	if (igmp_msg_len < (int)sizeof(struct igmp_mtrace)) {

pimd/pim_register.c

@@ -327,7 +327,7 @@ int pim_register_recv(struct interface *ifp, struct in_addr dest_addr,
 #define PIM_MSG_REGISTER_BIT_RESERVED_LEN 4
 	ip_hdr = (struct ip *)(tlv_buf + PIM_MSG_REGISTER_BIT_RESERVED_LEN);
 
-	if (!pim_rp_check_is_my_ip_address(pim, dest_addr)) {
+	if (!if_address_is_local(&dest_addr, AF_INET, pim->vrf->vrf_id)) {
 		if (PIM_DEBUG_PIM_REG) {
 			char dest[INET_ADDRSTRLEN];
 

pimd/pim_rp.c

@@ -1178,15 +1178,6 @@ int pim_rp_config_write(struct pim_instance *pim, struct vty *vty,
 	return count;
 }
 
-bool pim_rp_check_is_my_ip_address(struct pim_instance *pim,
-				   struct in_addr dest_addr)
-{
-	if (if_lookup_exact_address(&dest_addr, AF_INET, pim->vrf->vrf_id))
-		return true;
-
-	return false;
-}
-
 void pim_rp_show_information(struct pim_instance *pim, struct vty *vty, bool uj)
 {
 	struct rp_info *rp_info;

ripd/rip_snmp.c

@@ -257,7 +257,7 @@ static struct interface *rip2IfLookup(struct variable *v, oid name[],
 
 		oid2in_addr(name + v->namelen, sizeof(struct in_addr), addr);
 
-		return if_lookup_exact_address((void *)addr, AF_INET,
+		return if_lookup_address_local((void *)addr, AF_INET,
 					       VRF_DEFAULT);
 	} else {
 		len = *length - v->namelen;

staticd/static_routes.c

@@ -199,14 +199,14 @@ bool static_add_nexthop_validate(const char *nh_vrf_name,
 	switch (type) {
 	case STATIC_IPV4_GATEWAY:
 	case STATIC_IPV4_GATEWAY_IFNAME:
-		if (if_lookup_exact_address(&ipaddr->ipaddr_v4, AF_INET,
-					    vrf->vrf_id))
+		if (if_address_is_local(&ipaddr->ipaddr_v4, AF_INET,
+					vrf->vrf_id))
 			return false;
 		break;
 	case STATIC_IPV6_GATEWAY:
 	case STATIC_IPV6_GATEWAY_IFNAME:
-		if (if_lookup_exact_address(&ipaddr->ipaddr_v6, AF_INET6,
-					    vrf->vrf_id))
+		if (if_address_is_local(&ipaddr->ipaddr_v6, AF_INET6,
+					vrf->vrf_id))
 			return false;
 		break;
 	default:

staticd/static_zebra.c

@@ -162,14 +162,10 @@ static bool
 static_nexthop_is_local(vrf_id_t vrfid, struct prefix *addr, int family)
 {
 	if (family == AF_INET) {
-		if (if_lookup_exact_address(&addr->u.prefix4,
-					AF_INET,
-					vrfid))
+		if (if_address_is_local(&addr->u.prefix4, AF_INET, vrfid))
 			return true;
 	} else if (family == AF_INET6) {
-		if (if_lookup_exact_address(&addr->u.prefix6,
-					AF_INET6,
-					vrfid))
+		if (if_address_is_local(&addr->u.prefix6, AF_INET6, vrfid))
 			return true;
 	}
 	return false;