From ff4c92d85c6f2777d2067f8552e7fefb4d1754ae Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 4 Oct 2010 21:14:03 +0200 Subject: [PATCH] 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 Acked-by: David S. Miller Signed-off-by: John W. Linville --- include/net/genetlink.h | 18 ++++++++++++++++++ net/netlink/genetlink.c | 14 +++++++++++++- 2 files changed, 31 insertions(+), 1 deletion(-) 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) -- GitLab