add a ubus interface to dynamically create host routes to a particular ip address, returns the interface that the route goes through

5 files changed, 201 insertions, 6 deletions

diff --git a/interface-ip.c b/interface-ip.c
index 914ec07..ed68116 100644
--- a/interface-ip.c
+++ b/interface-ip.c
@@ -37,6 +37,120 @@ const struct config_param_list route_attr_list = {
 	.params = route_attr,
 };
 
+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;
+}
+
 void
 interface_ip_add_route(struct interface *iface, struct blob_attr *attr, bool v6)
 {
@@ -218,6 +332,30 @@ interface_update_proto_route(struct vlist_tree *tree,
 	}
 }
 
+static void
+interface_update_host_route(struct vlist_tree *tree,
+			     struct vlist_node *node_new,
+			     struct vlist_node *node_old)
+{
+	struct interface *iface;
+	struct device *dev;
+	struct device_route *route_old, *route_new;
+
+	iface = container_of(tree, struct interface, host_routes);
+	dev = iface->l3_dev.dev;
+
+	route_old = container_of(node_old, struct device_route, node);
+	route_new = container_of(node_new, struct device_route, node);
+
+	if (node_old) {
+		system_del_route(dev, route_old);
+		free(route_old);
+	}
+
+	if (node_new)
+		system_add_route(dev, route_new);
+}
+
 void
 interface_add_dns_server(struct interface_ip_settings *ip, const char *str)
 {
@@ -410,14 +548,16 @@ interface_ip_update_complete(struct interface_ip_settings *ip)
 void
 interface_ip_flush(struct interface_ip_settings *ip)
 {
+	if (ip == &ip->iface->proto_ip)
+		vlist_flush_all(&ip->iface->host_routes);
 	vlist_simple_flush_all(&ip->dns_servers);
 	vlist_simple_flush_all(&ip->dns_search);
 	vlist_flush_all(&ip->route);
 	vlist_flush_all(&ip->addr);
 }
 
-void
-interface_ip_init(struct interface_ip_settings *ip, struct interface *iface)
+static void
+__interface_ip_init(struct interface_ip_settings *ip, struct interface *iface)
 {
 	ip->iface = iface;
 	ip->enabled = true;
@@ -426,3 +566,11 @@ interface_ip_init(struct interface_ip_settings *ip, struct interface *iface)
 	vlist_init(&ip->route, route_cmp, interface_update_proto_route);
 	vlist_init(&ip->addr, addr_cmp, interface_update_proto_addr);
 }
+
+void
+interface_ip_init(struct interface *iface)
+{
+	__interface_ip_init(&iface->proto_ip, iface);
+	__interface_ip_init(&iface->config_ip, iface);
+	vlist_init(&iface->host_routes, route_cmp, interface_update_host_route);
+}
diff --git a/interface-ip.h b/interface-ip.h
index 28df093..bd1464c 100644
--- a/interface-ip.h
+++ b/interface-ip.h
@@ -64,7 +64,7 @@ struct dns_search_domain {
 
 extern const struct config_param_list route_attr_list;
 
-void interface_ip_init(struct interface_ip_settings *ip, struct interface *iface);
+void interface_ip_init(struct interface *iface);
 void interface_add_dns_server(struct interface_ip_settings *ip, const char *str);
 void interface_add_dns_server_list(struct interface_ip_settings *ip, struct blob_attr *list);
 void interface_add_dns_search_list(struct interface_ip_settings *ip, struct blob_attr *list);
@@ -78,4 +78,6 @@ void interface_ip_flush(struct interface_ip_settings *ip);
 void interface_ip_set_enabled(struct interface_ip_settings *ip, bool enabled);
 void interface_ip_update_metric(struct interface_ip_settings *ip, int metric);
 
+struct interface *interface_ip_add_target_route(union if_addr *addr, bool v6);
+
 #endif
diff --git a/interface.c b/interface.c
index 10a9174..9301628 100644
--- a/interface.c
+++ b/interface.c
@@ -352,8 +352,7 @@ interface_init(struct interface *iface, const char *name,
 	INIT_LIST_HEAD(&iface->errors);
 	INIT_LIST_HEAD(&iface->users);
 	INIT_LIST_HEAD(&iface->hotplug_list);
-	interface_ip_init(&iface->proto_ip, iface);
-	interface_ip_init(&iface->config_ip, iface);
+	interface_ip_init(iface);
 	avl_init(&iface->data, avl_strcmp, false, NULL);
 	iface->config_ip.enabled = false;
 
diff --git a/interface.h b/interface.h
index 5e3f383..c89411a 100644
--- a/interface.h
+++ b/interface.h
@@ -91,6 +91,7 @@ struct interface {
 
 	struct interface_ip_settings proto_ip;
 	struct interface_ip_settings config_ip;
+	struct vlist_tree host_routes;
 
 	int metric;
 
diff --git a/ubus.c b/ubus.c
index 4746c4f..33c94a1 100644
--- a/ubus.c
+++ b/ubus.c
@@ -27,16 +27,61 @@ netifd_handle_restart(struct ubus_context *ctx, struct ubus_object *obj,
 
 static int
 netifd_handle_reload(struct ubus_context *ctx, struct ubus_object *obj,
+		     struct ubus_request_data *req, const char *method,
+		     struct blob_attr *msg)
+{
+	netifd_reload();
+	return 0;
+}
+
+enum {
+	HR_TARGET,
+	HR_V6,
+	__HR_MAX
+};
+
+static const struct blobmsg_policy route_policy[__HR_MAX] = {
+	[HR_TARGET] = { .name = "target", .type = BLOBMSG_TYPE_STRING },
+	[HR_V6] = { .name = "v6", .type = BLOBMSG_TYPE_BOOL },
+};
+
+static int
+netifd_add_host_route(struct ubus_context *ctx, struct ubus_object *obj,
 		      struct ubus_request_data *req, const char *method,
 		      struct blob_attr *msg)
 {
-	netifd_reload();
+	struct blob_attr *tb[__HR_MAX];
+	struct interface *iface;
+	union if_addr a;
+	bool v6 = false;
+
+	blobmsg_parse(route_policy, __HR_MAX, tb, blob_data(msg), blob_len(msg));
+	if (!tb[HR_TARGET])
+		return UBUS_STATUS_INVALID_ARGUMENT;
+
+	if (tb[HR_V6])
+		v6 = blobmsg_get_bool(tb[HR_V6]);
+
+	memset(&a, 0, sizeof(a));
+	if (!inet_pton(v6 ? AF_INET6 : AF_INET, blobmsg_data(tb[HR_TARGET]), &a))
+		return UBUS_STATUS_INVALID_ARGUMENT;
+
+
+	iface = interface_ip_add_target_route(&a, v6);
+	if (!iface)
+		return UBUS_STATUS_NOT_FOUND;
+
+	blob_buf_init(&b, 0);
+	blobmsg_add_string(&b, "interface", iface->name);
+	ubus_send_reply(ctx, req, b.head);
+
 	return 0;
 }
 
 static struct ubus_method main_object_methods[] = {
 	{ .name = "restart", .handler = netifd_handle_restart },
 	{ .name = "reload", .handler = netifd_handle_reload },
+	UBUS_METHOD("add_host_route", netifd_add_host_route, route_policy),
 };
 
 static struct ubus_object_type main_object_type =