On Wed, 2020-09-30 at 09:44 -0700, Jakub Kicinski wrote:
> I started with a get_policy() callback, but I didn't like it much.
> Static data is much more pleasant for a client of the API IMHO.
Yeah, true.
> What do you think about "ops light"? Insufficiently flexible?
TBH, I'm not really sure how you'd do it?
Admittedly, it _would_ be nice to reduce struct genl_ops further, I
could imagine, assuming that doit is far more common than anything else,
perhaps something like
diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index b9eb92f3fe86..a5abab50673c 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -125,23 +125,34 @@ genl_dumpit_info(struct netlink_callback *cb)
return cb->data;
}
+/**
+ * struct genl_ops_ext - full generic netlink operations
+ * @start: start callback for dumps
+ * @dumpit: callback for dumpers
+ * @done: completion callback for dumps
+ * @policy: policy if different from the family policy
+ * @maxattr: max attr for the policy
+ */
+struct genl_ops_ext {
+ int (*start)(struct netlink_callback *cb);
+ int (*dumpit)(struct sk_buff *skb,
+ struct netlink_callback *cb);
+ int (*done)(struct netlink_callback *cb);
+ const struct nla_policy *policy;
+ unsigned int maxattr;
+};
+
/**
* struct genl_ops - generic netlink operations
* @cmd: command identifier
* @internal_flags: flags used by the family
* @flags: flags
* @doit: standard command callback
- * @start: start callback for dumps
- * @dumpit: callback for dumpers
- * @done: completion callback for dumps
*/
struct genl_ops {
int (*doit)(struct sk_buff *skb,
struct genl_info *info);
- int (*start)(struct netlink_callback *cb);
- int (*dumpit)(struct sk_buff *skb,
- struct netlink_callback *cb);
- int (*done)(struct netlink_callback *cb);
+ struct genl_ops_ext *extops;
u8 cmd;
u8 internal_flags;
u8 flags;
...
or perhaps even
diff --git a/include/net/genetlink.h b/include/net/genetlink.h
index b9eb92f3fe86..9be3fc051400 100644
--- a/include/net/genetlink.h
+++ b/include/net/genetlink.h
@@ -125,29 +125,45 @@ genl_dumpit_info(struct netlink_callback *cb)
return cb->data;
}
+/**
+ * struct genl_ops_ext - full generic netlink operations
+ * @start: start callback for dumps
+ * @dumpit: callback for dumpers
+ * @done: completion callback for dumps
+ * @doit: standard command callback
+ * @policy: policy if different from the family policy
+ * @maxattr: max attr for the policy
+ */
+struct genl_ops_ext {
+ int (*start)(struct netlink_callback *cb);
+ int (*dumpit)(struct sk_buff *skb, struct netlink_callback *cb);
+ int (*done)(struct netlink_callback *cb);
+ int (*doit)(struct sk_buff *skb, struct genl_info *info);
+ const struct nla_policy *policy;
+ unsigned int maxattr;
+};
+
/**
* struct genl_ops - generic netlink operations
* @cmd: command identifier
* @internal_flags: flags used by the family
* @flags: flags
* @doit: standard command callback
- * @start: start callback for dumps
- * @dumpit: callback for dumpers
- * @done: completion callback for dumps
+ * @extops: extended ops if needed, must use GENL_EXTOPS()
*/
struct genl_ops {
- int (*doit)(struct sk_buff *skb,
- struct genl_info *info);
- int (*start)(struct netlink_callback *cb);
- int (*dumpit)(struct sk_buff *skb,
- struct netlink_callback *cb);
- int (*done)(struct netlink_callback *cb);
+ union {
+ int (*doit)(struct sk_buff *skb, struct genl_info *info);
+ struct genl_ops_ext *extops;
+ };
u8 cmd;
u8 internal_flags;
u8 flags;
u8 validate;
};
+#define GENL_EXT_OPS(ptr) ((struct genl_ops_ext *)((uintptr_t)(ptr) | 1))
+
int genl_register_family(struct genl_family *family);
int genl_unregister_family(const struct genl_family *family);
void genl_notify(const struct genl_family *family, struct sk_buff *skb,
But both sort of feel awkward, you have to declare another structure,
and link it manually to the right place?
There isn't really a _good_ way to express such a thing easily in C?
johannes
