xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

net netlink: Add new type NLA_BITFIELD32

Browse Source 
Generic bitflags attribute content sent to the kernel by user.
With this netlink attr type the user can either set or unset a
flag in the kernel.

The value is a bitmap that defines the bit values being set
The selector is a bitmask that defines which value bit is to be
considered.

A check is made to ensure the rules that a kernel subsystem always
conforms to bitflags the kernel already knows about. i.e
if the user tries to set a bit flag that is not understood then
the _it will be rejected_.

In the most basic form, the user specifies the attribute policy as:
[ATTR_GOO] = { .type = NLA_BITFIELD32, .validation_data = &myvalidflags },

where myvalidflags is the bit mask of the flags the kernel understands.

If the user _does not_ provide myvalidflags then the attribute will
also be rejected.

Examples:
value = 0x0, and selector = 0x1
implies we are selecting bit 1 and we want to set its value to 0.

value = 0x2, and selector = 0x2
implies we are selecting bit 2 and we want to set its value to 1.

Suggested-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jamal Hadi Salim
2017-07-30 13:24:49 -04:00
committed by David S. Miller
parent fbbeefdd21
commit 64c83d8373
3 changed files with 63 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
include/uapi/linux/netlink.h
View File

@@ -226,5 +226,22 @@ struct nlattr {
#define NLA_ALIGN(len) (((len) + NLA_ALIGNTO - 1) & ~(NLA_ALIGNTO - 1))
#define NLA_HDRLEN ((int) NLA_ALIGN(sizeof(struct nlattr)))
/* Generic 32 bitflags attribute content sent to the kernel.
*
* The value is a bitmap that defines the values being set
* The selector is a bitmask that defines which value is legit
*
* Examples:
* value = 0x0, and selector = 0x1
* implies we are selecting bit 1 and we want to set its value to 0.
*
* value = 0x2, and selector = 0x2
* implies we are selecting bit 2 and we want to set its value to 1.
*
*/
struct nla_bitfield32 {
__u32 value;
__u32 selector;
};
#endif /* _UAPI__LINUX_NETLINK_H */