diff options
author | Patrick McHardy <kaber@trash.net> | 2007-06-25 21:30:16 (GMT) |
---|---|---|
committer | David S. Miller <davem@sunset.davemloft.net> | 2007-07-11 05:15:39 (GMT) |
commit | afdc3238ec948531205f5c5f77d2de7bae519c71 (patch) | |
tree | ce69a6ed3095ba5049673340304672381068b3af /net/core/rtnetlink.c | |
parent | 1092cb219774a82b1f16781aec7b8d4ec727c981 (diff) | |
download | linux-fsl-qoriq-afdc3238ec948531205f5c5f77d2de7bae519c71.tar.xz |
[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 'net/core/rtnetlink.c')
-rw-r--r-- | net/core/rtnetlink.c | 16 |
1 files changed, 16 insertions, 0 deletions
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); |