rsmnl-derive

I just want to write rsmnl-core examples shorter and more compact, and to try using Rust procedual macro. See examples in rsmnl-linux.

what is, by example

see examples/netfilter/nfct-daemon.rs and src/netfilter/nfnetlink_conntrack.rs.

define:

use { Msghdr, Attr, AttrTbl, Result };

#[repr(u16)]
#[derive(..., NlaType)
pub enum Parent {
    None = 0,
    One,
    Two,
    Three,
    _MAX
}

will implements std::convert::TryFrom and a few for Parent.

simple type

Then define nla_type by macro attribute:

[#nla_type(u32, one)]
One,

putting value to nlh: Msghdr (e.g. Nlmsghdr) can be done by:

use mnl:: { AttrTbl, Msghdr };
Parent::put_one(&mut nlv, 1234u32)

create tb data from read Msghdr, specify its table name:

#[tbname="ParentTbl"]
pub enum Parent {

Then, value can be accessed via:

let tb = ParentTbl::from_nlmsg(header_offset, nlh)?;
let one: Option<u32> = tb.one()?;
let attr: Option<&Attr> = tb[Parent::One]?;

nested type

Two is nested which is defined:

#[repr(u16)]
#[derive(..., NlaType)
#[tbname="ChildTbl"]
pub enum Child {
    None = 0,
    [#nla_type(str, one)]
    Ichi,
    Ni,
    San,
    _MAX
}

In enum Parent, define:

[#nla_nest(ChildTbl, two)]
Two,

Then Two can be acquire and access:

let two = tb.two()?;
let ichi = two.ichi()?;