2 files changed, 31 insertions, 1 deletions

diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index f7dcd2c70412..8a64b811a39a 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -20,6 +20,9 @@ struct genl_multicast_group {
         u32                     id;
 };
 
+struct genl_ops;
+struct genl_info;
+
 /**
  * struct genl_family - generic netlink family
  * @id: protocol family idenfitier
@@ -29,6 +32,10 @@ struct genl_multicast_group {
  * @maxattr: maximum number of attributes supported
  * @netnsok: set to true if the family can handle network
  *      namespaces and should be presented in all of them
+ * @pre_doit: called before an operation's doit callback, it may
+ *      do additional, common, filtering and return an error
+ * @post_doit: called after an operation's doit callback, it may
+ *      undo operations done by pre_doit, for example release locks
  * @attrbuf: buffer to store parsed attributes
  * @ops_list: list of all assigned operations
  * @family_list: family list
@@ -41,6 +48,12 @@ struct genl_family {
         unsigned int            version;
         unsigned int            maxattr;
         bool                    netnsok;
+        int                     (*pre_doit)(struct genl_ops *ops,
+                                            struct sk_buff *skb,
+                                            struct genl_info *info);
+        void                    (*post_doit)(struct genl_ops *ops,
+                                             struct sk_buff *skb,
+                                             struct genl_info *info);
         struct nlattr **        attrbuf;        /* private */
         struct list_head        ops_list;       /* private */
         struct list_head        family_list;    /* private */
@@ -55,6 +68,8 @@ struct genl_family {
  * @genlhdr: generic netlink message header
  * @userhdr: user specific header
  * @attrs: netlink attributes
+ * @_net: network namespace
+ * @user_ptr: user pointers
  */
 struct genl_info {
         u32                     snd_seq;
@@ -66,6 +81,7 @@ struct genl_info {
 #ifdef CONFIG_NET_NS
         struct net *            _net;
 #endif
+        void *                  user_ptr[2];
 };
 
 static inline struct net *genl_info_net(struct genl_info *info)
@@ -81,6 +97,7 @@ static inline void genl_info_net_set(struct genl_info *info, struct net *net)
 /**
  * struct genl_ops - generic netlink operations
  * @cmd: command identifier
+ * @internal_flags: flags used by the family
  * @flags: flags
  * @policy: attribute validation policy
  * @doit: standard command callback
@@ -90,6 +107,7 @@ static inline void genl_info_net_set(struct genl_info *info, struct net *net)
  */
 struct genl_ops {
         u8                      cmd;
+        u8                      internal_flags;
         unsigned int            flags;
         const struct nla_policy *policy;
         int                    (*doit)(struct sk_buff *skb,
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c
index 26ed3e8587c2..1781d99145e2 100644
--- a/net/netlink/genetlink.c
+++ b/net/netlink/genetlink.c
@@ -547,8 +547,20 @@ static int genl_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
         info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
         info.attrs = family->attrbuf;
         genl_info_net_set(&info, net);
+        memset(&info.user_ptr, 0, sizeof(info.user_ptr));
 
-        return ops->doit(skb, &info);
+        if (family->pre_doit) {
+                err = family->pre_doit(ops, skb, &info);
+                if (err)
+                        return err;
+        }
+
+        err = ops->doit(skb, &info);
+
+        if (family->post_doit)
+                family->post_doit(ops, skb, &info);
+
+        return err;
 }
 
 static void genl_rcv(struct sk_buff *skb)