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|
//! A module with all the nftables expressions that can be added to [`Rule`]s to build up how
//! they match against packets.
//!
//! [`Rule`]: struct.Rule.html
use std::fmt::Debug;
use rustables_macros::nfnetlink_struct;
use crate::error::DecodeError;
use crate::nlmsg::{NfNetlinkAttribute, NfNetlinkDeserializable};
use crate::parser_impls::NfNetlinkList;
use crate::sys::{self, NFTA_EXPR_DATA, NFTA_EXPR_NAME};
mod bitwise;
pub use self::bitwise::*;
mod cmp;
pub use self::cmp::*;
mod counter;
pub use self::counter::*;
pub mod ct;
pub use self::ct::*;
pub mod exthdr;
pub use self::exthdr::*;
mod immediate;
pub use self::immediate::*;
mod log;
pub use self::log::*;
mod lookup;
pub use self::lookup::*;
mod masquerade;
pub use self::masquerade::*;
mod meta;
pub use self::meta::*;
mod nat;
pub use self::nat::*;
mod payload;
pub use self::payload::*;
mod reject;
pub use self::reject::{IcmpCode, Reject, RejectType};
mod register;
pub use self::register::Register;
mod verdict;
pub use self::verdict::*;
pub trait Expression {
fn get_name() -> &'static str;
}
#[derive(Clone, PartialEq, Eq, Default, Debug)]
#[nfnetlink_struct(nested = true, derive_decoder = false)]
pub struct RawExpression {
#[field(NFTA_EXPR_NAME)]
name: String,
#[field(NFTA_EXPR_DATA)]
data: ExpressionVariant,
}
impl<T> From<T> for RawExpression
where
T: Expression,
ExpressionVariant: From<T>,
{
fn from(val: T) -> Self {
RawExpression::default()
.with_name(T::get_name())
.with_data(ExpressionVariant::from(val))
}
}
macro_rules! create_expr_variant {
($enum:ident $(, [$name:ident, $type:ty])+) => {
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum $enum {
$(
$name($type),
)+
}
impl $crate::nlmsg::NfNetlinkAttribute for $enum {
fn is_nested(&self) -> bool {
true
}
fn get_size(&self) -> usize {
match self {
$(
$enum::$name(val) => val.get_size(),
)+
}
}
fn write_payload(&self, addr: &mut [u8]) {
match self {
$(
$enum::$name(val) => val.write_payload(addr),
)+
}
}
}
$(
impl From<$type> for $enum {
fn from(val: $type) -> Self {
$enum::$name(val)
}
}
)+
impl $crate::nlmsg::AttributeDecoder for RawExpression {
fn decode_attribute(
&mut self,
attr_type: u16,
buf: &[u8],
) -> Result<(), $crate::error::DecodeError> {
debug!("Decoding attribute {} in an expression", attr_type);
match attr_type {
x if x == sys::NFTA_EXPR_NAME => {
debug!("Calling {}::deserialize()", std::any::type_name::<String>());
let (val, remaining) = String::deserialize(buf)?;
if remaining.len() != 0 {
return Err($crate::error::DecodeError::InvalidDataSize);
}
self.name = Some(val);
Ok(())
},
x if x == sys::NFTA_EXPR_DATA => {
// we can assume we have already the name parsed, as that's how we identify the
// type of expression
let name = self.name.as_ref()
.ok_or($crate::error::DecodeError::MissingExpressionName)?;
match name {
$(
x if x == <$type>::get_name() => {
debug!("Calling {}::deserialize()", std::any::type_name::<$type>());
let (res, remaining) = <$type>::deserialize(buf)?;
if remaining.len() != 0 {
return Err($crate::error::DecodeError::InvalidDataSize);
}
self.data = Some(ExpressionVariant::from(res));
Ok(())
},
)+
name => {
info!("Unrecognized expression '{}', generating an ExpressionRaw", name);
self.data = Some(ExpressionVariant::ExpressionRaw(ExpressionRaw::deserialize(buf)?.0));
Ok(())
}
}
},
_ => Err(DecodeError::UnsupportedAttributeType(attr_type)),
}
}
}
};
}
create_expr_variant!(
ExpressionVariant,
[Bitwise, Bitwise],
[Cmp, Cmp],
[Conntrack, Conntrack],
[Counter, Counter],
[ExpressionRaw, ExpressionRaw],
[Immediate, Immediate],
[Log, Log],
[Lookup, Lookup],
[Masquerade, Masquerade],
[Meta, Meta],
[Nat, Nat],
[Payload, Payload],
[Reject, Reject]
);
pub type ExpressionList = NfNetlinkList<RawExpression>;
// default type for expressions that we do not handle yet
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ExpressionRaw(Vec<u8>);
impl NfNetlinkAttribute for ExpressionRaw {
fn get_size(&self) -> usize {
self.0.get_size()
}
fn write_payload(&self, addr: &mut [u8]) {
self.0.write_payload(addr);
}
}
impl NfNetlinkDeserializable for ExpressionRaw {
fn deserialize(buf: &[u8]) -> Result<(Self, &[u8]), DecodeError> {
Ok((ExpressionRaw(buf.to_vec()), &[]))
}
}
// Because we loose the name of the expression when parsing, this is the only expression
// where deserializing a message and then reserializing it is invalid
impl Expression for ExpressionRaw {
fn get_name() -> &'static str {
"unknown_expression"
}
}
|
