vpn: support IPv6 over VPNs

Add new API to allow passing both IPv4 and IPv6 configuration
information from VPN plugins to the backend.

Now instead of a single Ip4Config, a plugin has Config, Ip4Config, and
Ip6Config. "Config" contains information which is neither IPv4 nor
IPv6 specific, and also indicates which of Ip4Config and Ip6Config are
present. Ip4Config now only contains the IPv4-specific bits of
configuration.

There is backward compatibility in both directions: if the daemon is
new and the VPN plugin is old, then NM will notice that the plugin
emitted the Ip4Config signal without having emitted the Config signal
first, and so will assume that it is IPv4-only, and that the generic
bits of configuration have been included with the Ip4Config. If the
daemon is old and the plugin is new, then NMVPNPlugin will copy the
values from the generic config into the IPv4 config as well. (In fact,
NMVPNPlugin *always* does this, because it's harmless, and it's easier
than actually checking the daemon version.)

Currently the VPN is still configured all-at-once, after both IPv4 and
IPv6 information has been received, but the APIs allow for the
possibility of configuring them one at a time in the future.

include/NetworkManagerVPN.h

@@ -114,8 +114,28 @@ typedef enum {
 } NMVPNPluginFailure;
 
 
+/*** Generic config ***/
+
+/* string: VPN interface name (tun0, tap0, etc) */
+#define NM_VPN_PLUGIN_CONFIG_TUNDEV      "tundev"
+
+/* string: Login message */
+#define NM_VPN_PLUGIN_CONFIG_BANNER      "banner"
+
 /* uint32 / array of uint8: IP address of the public external VPN gateway (network byte order) */
-#define NM_VPN_PLUGIN_IP4_CONFIG_EXT_GATEWAY "gateway"
+#define NM_VPN_PLUGIN_CONFIG_EXT_GATEWAY "gateway"
+
+/* uint32: Maximum Transfer Unit that the VPN interface should use */
+#define NM_VPN_PLUGIN_CONFIG_MTU         "mtu"
+
+/* boolean: Has IP4 configuration? */
+#define NM_VPN_PLUGIN_CONFIG_HAS_IP4     "has-ip4"
+
+/* boolean: Has IP6 configuration? */
+#define NM_VPN_PLUGIN_CONFIG_HAS_IP6     "has-ip6"
+
+
+/*** Ip4Config ***/
 
 /* uint32: IP address of the internal gateway of the subnet the VPN interface is
  *         on, if the VPN uses subnet configuration (network byte order)
@@ -142,30 +162,14 @@ typedef enum {
 /* uint32: Message Segment Size that the VPN interface should use */
 #define NM_VPN_PLUGIN_IP4_CONFIG_MSS         "mss"
 
-/* uint32: Maximum Transfer Unit that the VPN interface should use */
-#define NM_VPN_PLUGIN_IP4_CONFIG_MTU         "mtu"
-
-/* string: VPN interface name (tun0, tap0, etc) */
-#define NM_VPN_PLUGIN_IP4_CONFIG_TUNDEV      "tundev"
-
 /* string: DNS domain name */
 #define NM_VPN_PLUGIN_IP4_CONFIG_DOMAIN      "domain"
 
 /* array of strings: DNS domain names */
 #define NM_VPN_PLUGIN_IP4_CONFIG_DOMAINS     "domains"
 
-/* string: Login message */
-#define NM_VPN_PLUGIN_IP4_CONFIG_BANNER      "banner"
-
-/* array of array of uint32: custom routes the client should apply.  NOTE: NM
- *     expects the D-Bus argument signature "aau" here.  i.e., an array of
- *     routes, where each route is a 4-element array of uint32 values.
- *
- *     Each route consists of the following 4 uint32 values, in this order:
- *              1: destination IP address (network byte order)
- *              2: destination prefix (1 - 32 inclusive)
- *              3: IP address of next hop (network byte order)
- *              4: route metric
+/* [ip4 routes]: custom routes the client should apply, in the format used
+ *         by nm_utils_ip4_routes_to/from_gvalue
  */
 #define NM_VPN_PLUGIN_IP4_CONFIG_ROUTES      "routes"
 
@@ -175,5 +179,52 @@ typedef enum {
 /* Deprecated */
 #define NM_VPN_PLUGIN_IP4_CONFIG_GATEWAY   NM_VPN_PLUGIN_IP4_CONFIG_EXT_GATEWAY
 
+/* Legacy IP4 items; these are included in the IP4 config by older plugins,
+ * but in the generic config by newer plugins.
+ */
+
+#define NM_VPN_PLUGIN_IP4_CONFIG_BANNER      NM_VPN_PLUGIN_CONFIG_BANNER
+#define NM_VPN_PLUGIN_IP4_CONFIG_EXT_GATEWAY NM_VPN_PLUGIN_CONFIG_EXT_GATEWAY
+#define NM_VPN_PLUGIN_IP4_CONFIG_MTU         NM_VPN_PLUGIN_CONFIG_MTU
+#define NM_VPN_PLUGIN_IP4_CONFIG_TUNDEV      NM_VPN_PLUGIN_CONFIG_TUNDEV
+
+
+/*** Ip6Config ***/
+
+/* array of uint8: IP address of the internal gateway of the subnet the VPN interface is
+ *         on, if the VPN uses subnet configuration (network byte order)
+ */
+#define NM_VPN_PLUGIN_IP6_CONFIG_INT_GATEWAY "internal-gateway"
+
+/* array of uint8: internal IP address of the local VPN interface (network byte order) */
+#define NM_VPN_PLUGIN_IP6_CONFIG_ADDRESS     "address"
+
+/* array of uint8: IP address of the other side of Point-to-Point connection if the VPN
+ *         uses Point-to-Point configuration. (network byte order)
+ */
+#define NM_VPN_PLUGIN_IP6_CONFIG_PTP         "ptp"
+
+/* uint32: prefix length of the VPN interface; 1 - 128 inclusive */
+#define NM_VPN_PLUGIN_IP6_CONFIG_PREFIX      "prefix"
+
+/* array of array of uint8: IP addresses of DNS servers for the VPN (network byte order) */
+#define NM_VPN_PLUGIN_IP6_CONFIG_DNS         "dns"
+
+/* uint32: Message Segment Size that the VPN interface should use */
+#define NM_VPN_PLUGIN_IP6_CONFIG_MSS         "mss"
+
+/* string: DNS domain name */
+#define NM_VPN_PLUGIN_IP6_CONFIG_DOMAIN      "domain"
+
+/* array of strings: DNS domain names */
+#define NM_VPN_PLUGIN_IP6_CONFIG_DOMAINS     "domains"
+
+/* [ip6 routes]: custom routes the client should apply, in the format used
+ *         by nm_utils_ip6_routes_to/from_gvalue
+ */
+#define NM_VPN_PLUGIN_IP6_CONFIG_ROUTES      "routes"
+
+/* boolean: prevent this VPN connection from ever getting the default route */
+#define NM_VPN_PLUGIN_IP6_CONFIG_NEVER_DEFAULT "never-default"
 
 #endif /* NETWORK_MANAGER_VPN_H */