Sometimes doit/dumpit callbacks for a given family consist
of quite a bit of boilerplate code, for example locking or
generic sanity checks on messages.
These methods allow writing the boilerplate code just once
instead of copying it into all handlers.
Signed-off-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
---
I'd like to have this go in via the wireless tree because I have a
bugfix for that tree which depends on this infrastructure.
Note: struct genl_info just moves.
include/net/genetlink.h | 47 ++++++++++++++++++++++++++++-------------------
net/netlink/genetlink.c | 19 ++++++++++++++++---
2 files changed, 44 insertions(+), 22 deletions(-)
--- wireless-testing.orig/include/net/genetlink.h 2009-02-13 09:14:26.000000000 +0100
+++ wireless-testing/include/net/genetlink.h 2009-02-13 10:00:37.000000000 +0100
@@ -21,12 +21,35 @@ struct genl_multicast_group
};
/**
+ * struct genl_info - receiving information
+ * @snd_seq: sending sequence number
+ * @snd_pid: netlink pid of sender
+ * @nlhdr: netlink message header
+ * @genlhdr: generic netlink message header
+ * @userhdr: user specific header
+ * @attrs: netlink attributes
+ */
+struct genl_info
+{
+ u32 snd_seq;
+ u32 snd_pid;
+ struct nlmsghdr * nlhdr;
+ struct genlmsghdr * genlhdr;
+ void * userhdr;
+ struct nlattr ** attrs;
+};
+
+/**
* struct genl_family - generic netlink family
* @id: protocol family idenfitier
* @hdrsize: length of user specific header in bytes
* @name: name of family
* @version: protocol version
* @maxattr: maximum number of attributes supported
+ * @pre_doit: called before any doit op
+ * @post_doit: called after any doit op
+ * @pre_dumpit: called before any dumpit op
+ * @post_dumpit: called after any dumpit op
* @attrbuf: buffer to store parsed attributes
* @ops_list: list of all assigned operations
* @family_list: family list
@@ -39,6 +62,11 @@ struct genl_family
char name[GENL_NAMSIZ];
unsigned int version;
unsigned int maxattr;
+ int (*pre_doit)(struct sk_buff *skb,
+ struct genl_info *info);
+ void (*post_doit)(void);
+ int (*pre_dumpit)(void);
+ void (*post_dumpit)(void);
struct nlattr ** attrbuf; /* private */
struct list_head ops_list; /* private */
struct list_head family_list; /* private */
@@ -46,25 +74,6 @@ struct genl_family
};
/**
- * struct genl_info - receiving information
- * @snd_seq: sending sequence number
- * @snd_pid: netlink pid of sender
- * @nlhdr: netlink message header
- * @genlhdr: generic netlink message header
- * @userhdr: user specific header
- * @attrs: netlink attributes
- */
-struct genl_info
-{
- u32 snd_seq;
- u32 snd_pid;
- struct nlmsghdr * nlhdr;
- struct genlmsghdr * genlhdr;
- void * userhdr;
- struct nlattr ** attrs;
-};
-
-/**
* struct genl_ops - generic netlink operations
* @cmd: command identifier
* @flags: flags
--- wireless-testing.orig/net/netlink/genetlink.c 2009-02-13 09:14:26.000000000 +0100
+++ wireless-testing/net/netlink/genetlink.c 2009-02-13 09:54:32.000000000 +0100
@@ -446,8 +446,14 @@ static int genl_rcv_msg(struct sk_buff *
return -EOPNOTSUPP;
genl_unlock();
- err = netlink_dump_start(genl_sock, skb, nlh,
- ops->dumpit, ops->done);
+ err = 0;
+ if (family->pre_dumpit)
+ err = family->pre_dumpit();
+ if (!err)
+ err = netlink_dump_start(genl_sock, skb, nlh,
+ ops->dumpit, ops->done);
+ if (family->post_dumpit)
+ family->post_dumpit();
genl_lock();
return err;
}
@@ -469,7 +475,14 @@ static int genl_rcv_msg(struct sk_buff *
info.userhdr = nlmsg_data(nlh) + GENL_HDRLEN;
info.attrs = family->attrbuf;
- return ops->doit(skb, &info);
+ err = 0;
+ if (family->pre_doit)
+ err = family->pre_doit(skb, &info);
+ if (!err)
+ err = ops->doit(skb, &info);
+ if (family->post_doit)
+ family->post_doit();
+ return err;
}
static void genl_rcv(struct sk_buff *skb)
--
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