Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=afdc3238ec948531205f5c5f77d2de7bae519c71
Commit: afdc3238ec948531205f5c5f77d2de7bae519c71
Parent: 1092cb219774a82b1f16781aec7b8d4ec727c981
Author: Patrick McHardy <[EMAIL PROTECTED]>
AuthorDate: Mon Jun 25 14:30:16 2007 -0700
Committer: David S. Miller <[EMAIL PROTECTED]>
CommitDate: Tue Jul 10 22:15:39 2007 -0700
[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 <[EMAIL PROTECTED]>
Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
---
include/linux/rtnetlink.h | 14 ++++++++++++++
net/core/rtnetlink.c | 16 ++++++++++++++++
2 files changed, 30 insertions(+), 0 deletions(-)
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index 6127858..6731e7f 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); \
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 06c0c5a..c25d23b 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -97,6 +97,21 @@ int rtattr_parse(struct rtattr *tb[], int maxattr, struct
rtattr *rta, int len)
return 0;
}
+int rtattr_parse_nested_compat(struct rtattr *tb[], int maxattr,
+ struct rtattr *rta, void **data, int len)
+{
+ if (RTA_PAYLOAD(rta) < len)
+ return -1;
+ *data = RTA_DATA(rta);
+
+ if (RTA_PAYLOAD(rta) >= RTA_ALIGN(len) + sizeof(struct rtattr)) {
+ rta = RTA_DATA(rta) + RTA_ALIGN(len);
+ return rtattr_parse_nested(tb, maxattr, rta);
+ }
+ memset(tb, 0, sizeof(struct rtattr *) * maxattr);
+ return 0;
+}
+
static struct rtnl_link *rtnl_msg_handlers[NPROTO];
static inline int rtm_msgindex(int msgtype)
@@ -1297,6 +1312,7 @@ void __init rtnetlink_init(void)
EXPORT_SYMBOL(__rta_fill);
EXPORT_SYMBOL(rtattr_strlcpy);
EXPORT_SYMBOL(rtattr_parse);
+EXPORT_SYMBOL(rtattr_parse_nested_compat);
EXPORT_SYMBOL(rtnetlink_put_metrics);
EXPORT_SYMBOL(rtnl_lock);
EXPORT_SYMBOL(rtnl_trylock);
-
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