diff options
| author | Patrick McHardy <kaber@trash.net> | 2007-06-25 14:30:16 -0700 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-07-10 22:15:39 -0700 |
| commit | afdc3238ec948531205f5c5f77d2de7bae519c71 (patch) | |
| tree | ce69a6ed3095ba5049673340304672381068b3af /include/linux/rtnetlink.h | |
| parent | 1092cb219774a82b1f16781aec7b8d4ec727c981 (diff) | |
[RTNETLINK]: Add nested compat attribute
Add a nested compat attribute type that can be used to convert
attributes that contain a structure to nested attributes in a
backwards compatible way.
The attribute looks like this:
struct {
[ compat contents ]
struct rtattr {
.rta_len = total size,
.rta_type = type,
} rta;
struct old_structure struct;
[ nested top-level attribute ]
struct rtattr {
.rta_len = nest size,
.rta_type = type,
} nest_attr;
[ optional 0 .. n nested attributes ]
struct rtattr {
.rta_len = private attribute len,
.rta_type = private attribute typ,
} nested_attr;
struct nested_data data;
};
Since both userspace and kernel deal correctly with attributes that are
larger than expected old versions will just parse the compat part and
ignore the rest.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/linux/rtnetlink.h')
| -rw-r--r-- | include/linux/rtnetlink.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index 61278584853..6731e7f4cc0 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -570,6 +570,8 @@ static __inline__ int rtattr_strcmp(const struct rtattr *rta, const char *str) } extern int rtattr_parse(struct rtattr *tb[], int maxattr, struct rtattr *rta, int len); +extern int rtattr_parse_nested_compat(struct rtattr *tb[], int maxattr, + struct rtattr *rta, void **data, int len); #define rtattr_parse_nested(tb, max, rta) \ rtattr_parse((tb), (max), RTA_DATA((rta)), RTA_PAYLOAD((rta))) @@ -638,6 +640,18 @@ extern void __rta_fill(struct sk_buff *skb, int attrtype, int attrlen, const voi ({ (start)->rta_len = skb_tail_pointer(skb) - (unsigned char *)(start); \ (skb)->len; }) +#define RTA_NEST_COMPAT(skb, type, attrlen, data) \ +({ struct rtattr *__start = (struct rtattr *)skb_tail_pointer(skb); \ + RTA_PUT(skb, type, attrlen, data); \ + RTA_NEST(skb, type); \ + __start; }) + +#define RTA_NEST_COMPAT_END(skb, start) \ +({ struct rtattr *__nest = (void *)(start) + NLMSG_ALIGN((start)->rta_len); \ + (start)->rta_len = skb_tail_pointer(skb) - (unsigned char *)(start); \ + RTA_NEST_END(skb, __nest); \ + (skb)->len; }) + #define RTA_NEST_CANCEL(skb, start) \ ({ if (start) \ skb_trim(skb, (unsigned char *) (start) - (skb)->data); \ |