add basic support for jail network namespaces

Prepare netifd for handling procd service jails having their own
network namespace.
Intefaces having the jail attribute will only be brought inside the
jail's network namespace by procd calling the newly introduced ubus
method 'netns_updown'.
Currently proto 'static' is supported and configuration changes are
not yet being handled (ie. you'll have to restart the jailed service
for changes to take effect).

Example /etc/config/network snippet:

config device 'veth0'
    option type 'veth'
    option name 'vhost0'
    option peer_name 'virt0'

config interface 'virt'
    option type 'bridge'
    list ifname 'vhost0'
    option proto 'static'
    option ipaddr '10.0.0.1'
    option netmask '255.255.255.0'

config interface 'virt0'
    option ifname 'virt0'
    option proto 'static'
    option ipaddr '10.0.0.2'
    option netmask '255.255.255.0'
    option gateway '10.0.0.1'
    option dns '10.0.0.1'
    option jail 'transmission'

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

1 files changed, 43 insertions, 0 deletions

diff --git a/ubus.c b/ubus.c
index 5a2a339..85d834d 100644
--- a/ubus.c
+++ b/ubus.c
@@ -157,12 +157,52 @@ error:
 	return UBUS_STATUS_UNKNOWN_ERROR;
 }
 
+enum {
+	NETNS_UPDOWN_JAIL,
+	NETNS_UPDOWN_PID,
+	NETNS_UPDOWN_START,
+	__NETNS_UPDOWN_MAX
+};
+
+static const struct blobmsg_policy netns_updown_policy[__NETNS_UPDOWN_MAX] = {
+	[NETNS_UPDOWN_JAIL] = { .name = "jail", .type = BLOBMSG_TYPE_STRING },
+	[NETNS_UPDOWN_PID] = { .name = "pid", .type = BLOBMSG_TYPE_INT32 },
+	[NETNS_UPDOWN_START] = { .name = "start", .type = BLOBMSG_TYPE_BOOL },
+};
+
+static int
+netifd_netns_updown(struct ubus_context *ctx, struct ubus_object *obj,
+		  struct ubus_request_data *req, const char *method,
+		  struct blob_attr *msg)
+{
+	struct blob_attr *tb[__NETNS_UPDOWN_MAX];
+	char *jail;
+	pid_t netns_pid;
+	bool start;
+
+	blobmsg_parse(netns_updown_policy, __NETNS_UPDOWN_MAX, tb, blob_data(msg), blob_len(msg));
+	if (!tb[NETNS_UPDOWN_JAIL] || !tb[NETNS_UPDOWN_PID])
+		return UBUS_STATUS_INVALID_ARGUMENT;
+
+	start = tb[NETNS_UPDOWN_START] && blobmsg_get_bool(tb[NETNS_UPDOWN_START]);
+	jail = blobmsg_get_string(tb[NETNS_UPDOWN_JAIL]);
+	netns_pid = blobmsg_get_u32(tb[NETNS_UPDOWN_PID]);
+
+	if (start)
+		interface_start_jail(jail, netns_pid);
+	else
+		interface_stop_jail(jail, netns_pid);
+
+	return UBUS_STATUS_OK;
+}
+
 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),
 	{ .name = "get_proto_handlers", .handler = netifd_get_proto_handlers },
 	UBUS_METHOD("add_dynamic", netifd_add_dynamic, dynamic_policy),
+	UBUS_METHOD("netns_updown", netifd_netns_updown, netns_updown_policy),
 };
 
 static struct ubus_object_type main_object_type =
@@ -722,6 +762,9 @@ netifd_dump_status(struct interface *iface)
 	    !(iface->proto_handler->flags & PROTO_FLAG_NODEV))
 		blobmsg_add_string(&b, "device", dev->ifname);
 
+	if (iface->jail)
+		blobmsg_add_string(&b, "jail", iface->jail);
+
 	if (iface->state == IFS_UP) {
 		if (iface->updated) {
 			a = blobmsg_open_array(&b, "updated");