net netlink: Add new type NLA_BITFIELD32
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>
diff --git a/include/net/netlink.h b/include/net/netlink.h
index ef8e6c3..82dd298 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -178,6 +178,7 @@ enum {
NLA_S16,
NLA_S32,
NLA_S64,
+ NLA_BITFIELD32,
__NLA_TYPE_MAX,
};
@@ -206,6 +207,7 @@ enum {
* NLA_MSECS Leaving the length field zero will verify the
* given type fits, using it verifies minimum length
* just like "All other"
+ * NLA_BITFIELD32 A 32-bit bitmap/bitselector attribute
* All other Minimum length of attribute payload
*
* Example:
@@ -213,11 +215,13 @@ enum {
* [ATTR_FOO] = { .type = NLA_U16 },
* [ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },
* [ATTR_BAZ] = { .len = sizeof(struct mystruct) },
+ * [ATTR_GOO] = { .type = NLA_BITFIELD32, .validation_data = &myvalidflags },
* };
*/
struct nla_policy {
u16 type;
u16 len;
+ void *validation_data;
};
/**
@@ -1203,6 +1207,18 @@ static inline struct in6_addr nla_get_in6_addr(const struct nlattr *nla)
}
/**
+ * nla_get_bitfield32 - return payload of 32 bitfield attribute
+ * @nla: nla_bitfield32 attribute
+ */
+static inline struct nla_bitfield32 nla_get_bitfield32(const struct nlattr *nla)
+{
+ struct nla_bitfield32 tmp;
+
+ nla_memcpy(&tmp, nla, sizeof(tmp));
+ return tmp;
+}
+
+/**
* nla_memdup - duplicate attribute memory (kmemdup)
* @src: netlink attribute to duplicate from
* @gfp: GFP mask