Re: [PATCH net-next v11 1/4] net netlink: Add new type NLA_BITFIELD_32
From: Jiri Pirko <jiri@resnulli.us>
Date: 2017-07-24 11:18:08
Mon, Jul 24, 2017 at 03:35:43AM CEST, jhs@mojatatu.com wrote:
From: Jamal Hadi Salim <jhs@mojatatu.com>
Generic bitflags attribute content sent to the kernel by user.
With this type the user can either set or unset a flag in the
kernel.
The nla_value is a bitmap that defines the values being set
The nla_selector is a bitmask that defines which value is legit.
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_BITFIELD_32, .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:
nla_value = 0x0, and nla_selector = 0x1
implies we are selecting bit 1 and we want to set its value to 0.
nla_value = 0x2, and nla_selector = 0x2
implies we are selecting bit 2 and we want to set its value to 1.Oh, 2 more things: [...]
quoted hunk ↗ jump to hunk
@@ -46,6 +60,13 @@ static int validate_nla(const struct nlattr *nla, int maxtype,return -ERANGE; break; + case NLA_BITFIELD_32:
Now that I'm looking at it, perhaps just "NLA_BITFIELD32" looks nicer and aligns with "NLA_U32" and others.
+ if (attrlen != sizeof(struct nla_bitfield_32)) + return -ERANGE; + + return validate_nla_bitfield_32(nla, pt->validation_data); + break;
Remove the pointless "break" from here.