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authorJohannes Berg <johannes.berg@intel.com>2010-10-04 21:14:03 +0200
committerJohn W. Linville <linville@tuxdriver.com>2010-10-05 19:35:30 +0200
commitff4c92d85c6f2777d2067f8552e7fefb4d1754ae (patch)
tree77e35603821e5602e96c90644e42e70f097ad79c
parentipw2200: check for allocation failures (diff)
downloadlinux-ff4c92d85c6f2777d2067f8552e7fefb4d1754ae.tar.xz
linux-ff4c92d85c6f2777d2067f8552e7fefb4d1754ae.zip
genetlink: introduce pre_doit/post_doit hooks
Each family may have some amount of boilerplate locking code that applies to most, or even all, commands. This allows a family to handle such things in a more generic way, by allowing it to a) include private flags in each operation b) specify a pre_doit hook that is called, before an operation's doit() callback and may return an error directly, c) specify a post_doit hook that can undo locking or similar things done by pre_doit, and finally d) include two private pointers in each info struct passed between all these operations including doit(). (It's two because I'll need two in nl80211 -- can be extended.) Signed-off-by: Johannes Berg <johannes.berg@intel.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
-rw-r--r--include/net/genetlink.h18
-rw-r--r--net/netlink/genetlink.c14
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)