+static bool
+match_if_addr(union if_addr *a1, union if_addr *a2, int mask)
+{
+ uint8_t *p1, *p2;
+ int m_bytes = (mask + 7) / 8;
+ uint8_t m_clear = (1 << (m_bytes * 8 - mask)) - 1;
+
+ p1 = alloca(m_bytes);
+ p2 = alloca(m_bytes);
+
+ memcpy(p1, a1, m_bytes);
+ memcpy(p2, a2, m_bytes);
+
+ p1[m_bytes - 1] &= ~m_clear;
+ p2[m_bytes - 1] &= ~m_clear;
+
+ return !memcmp(p1, p2, m_bytes);
+}
+
+static bool
+__find_ip_addr_target(struct interface_ip_settings *ip, union if_addr *a, bool v6)
+{
+ struct device_addr *addr;
+
+ vlist_for_each_element(&ip->addr, addr, node) {
+ if (!addr->enabled)
+ continue;
+
+ if (v6 != ((addr->flags & DEVADDR_FAMILY) == DEVADDR_INET6))
+ continue;
+
+ if (!match_if_addr(&addr->addr, a, addr->mask))
+ continue;
+
+ return true;
+ }
+
+ return false;
+}
+
+static void
+__find_ip_route_target(struct interface_ip_settings *ip, union if_addr *a,
+ bool v6, struct device_route **res)
+{
+ struct device_route *route;
+
+ vlist_for_each_element(&ip->route, route, node) {
+ if (!route->enabled)
+ continue;
+
+ if (v6 != ((route->flags & DEVADDR_FAMILY) == DEVADDR_INET6))
+ continue;
+
+ if (!match_if_addr(&route->addr, a, route->mask))
+ continue;
+
+ if (!*res || route->mask < (*res)->mask)
+ *res = route;
+ }
+}
+
+static bool
+interface_ip_find_addr_target(struct interface *iface, union if_addr *a, bool v6)
+{
+ return __find_ip_addr_target(&iface->proto_ip, a, v6) ||
+ __find_ip_addr_target(&iface->config_ip, a, v6);
+}
+
+static void
+interface_ip_find_route_target(struct interface *iface, union if_addr *a,
+ bool v6, struct device_route **route)
+{
+ __find_ip_route_target(&iface->proto_ip, a, v6, route);
+ __find_ip_route_target(&iface->config_ip, a, v6, route);
+}
+
+struct interface *
+interface_ip_add_target_route(union if_addr *addr, bool v6)
+{
+ struct interface *iface;
+ struct device_route *route, *r_next = NULL;
+
+ route = calloc(1, sizeof(*route));
+ if (!route)
+ return false;
+
+ route->flags = v6 ? DEVADDR_INET6 : DEVADDR_INET4;
+ route->mask = v6 ? 128 : 32;
+ memcpy(&route->addr, addr, v6 ? sizeof(addr->in6) : sizeof(addr->in));
+
+ vlist_for_each_element(&interfaces, iface, node) {
+ /* look for locally addressable target first */
+ if (interface_ip_find_addr_target(iface, addr, v6))
+ goto done;
+
+ /* do not stop at the first route, let the lookup compare
+ * masks to find the best match */
+ interface_ip_find_route_target(iface, addr, v6, &r_next);
+ }
+
+ if (!r_next)
+ return NULL;
+
+ iface = r_next->iface;
+ memcpy(&route->nexthop, &r_next->nexthop, sizeof(route->nexthop));
+ route->mtu = r_next->mtu;
+ route->metric = r_next->metric;
+
+done:
+ route->iface = iface;
+ vlist_add(&iface->host_routes, &route->node, &route->flags);
+ return iface;
+}
+