[GENETLINK]: Dynamic multicast groups.

Introduce API to dynamically register and unregister multicast groups.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Patrick McHardy <kaber@trash.net>
Acked-by: Jamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 35 insertions, 0 deletions

diff --git a/include/linux/genetlink.h b/include/linux/genetlink.h
index f7a93770e1b..7da02c93002 100644
--- a/include/linux/genetlink.h
+++ b/include/linux/genetlink.h
@@ -39,6 +39,9 @@ enum {
         CTRL_CMD_NEWOPS,
         CTRL_CMD_DELOPS,
         CTRL_CMD_GETOPS,
+        CTRL_CMD_NEWMCAST_GRP,
+        CTRL_CMD_DELMCAST_GRP,
+        CTRL_CMD_GETMCAST_GRP, /* unused */
         __CTRL_CMD_MAX,
 };
 
@@ -52,6 +55,7 @@ enum {
         CTRL_ATTR_HDRSIZE,
         CTRL_ATTR_MAXATTR,
         CTRL_ATTR_OPS,
+        CTRL_ATTR_MCAST_GROUPS,
         __CTRL_ATTR_MAX,
 };
 
@@ -66,4 +70,13 @@ enum {
 
 #define CTRL_ATTR_OP_MAX (__CTRL_ATTR_OP_MAX - 1)
 
+enum {
+        CTRL_ATTR_MCAST_GRP_UNSPEC,
+        CTRL_ATTR_MCAST_GRP_NAME,
+        CTRL_ATTR_MCAST_GRP_ID,
+        __CTRL_ATTR_MCAST_GRP_MAX,
+};
+
+#define CTRL_ATTR_MCAST_GRP_MAX (__CTRL_ATTR_MCAST_GRP_MAX - 1)
+
 #endif  /* __LINUX_GENERIC_NETLINK_H */
diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index b6eaca122db..decdda54682 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -5,6 +5,22 @@
 #include <net/netlink.h>
 
 /**
+ * struct genl_multicast_group - generic netlink multicast group
+ * @name: name of the multicast group, names are per-family
+ * @id: multicast group ID, assigned by the core, to use with
+ *      genlmsg_multicast().
+ * @list: list entry for linking
+ * @family: pointer to family, need not be set before registering
+ */
+struct genl_multicast_group
+{
+        struct genl_family      *family;        /* private */
+        struct list_head        list;           /* private */
+        char                    name[GENL_NAMSIZ];
+        u32                     id;
+};
+
+/**
  * struct genl_family - generic netlink family
  * @id: protocol family idenfitier
  * @hdrsize: length of user specific header in bytes
@@ -14,6 +30,7 @@
  * @attrbuf: buffer to store parsed attributes
  * @ops_list: list of all assigned operations
  * @family_list: family list
+ * @mcast_groups: multicast groups list
  */
 struct genl_family
 {
@@ -25,6 +42,7 @@ struct genl_family
         struct nlattr **        attrbuf;        /* private */
         struct list_head        ops_list;       /* private */
         struct list_head        family_list;    /* private */
+        struct list_head        mcast_groups;   /* private */
 };
 
 /**
@@ -73,6 +91,10 @@ extern int genl_register_family(struct genl_family *family);
 extern int genl_unregister_family(struct genl_family *family);
 extern int genl_register_ops(struct genl_family *, struct genl_ops *ops);
 extern int genl_unregister_ops(struct genl_family *, struct genl_ops *ops);
+extern int genl_register_mc_group(struct genl_family *family,
+                                  struct genl_multicast_group *grp);
+extern void genl_unregister_mc_group(struct genl_family *family,
+                                     struct genl_multicast_group *grp);
 
 extern struct sock *genl_sock;