diff options
Diffstat (limited to 'src/parser.rs')
| -rw-r--r-- | src/parser.rs | 115 |
1 files changed, 77 insertions, 38 deletions
diff --git a/src/parser.rs b/src/parser.rs index 8e12c5e..2d05f4f 100644 --- a/src/parser.rs +++ b/src/parser.rs @@ -1,7 +1,7 @@ use std::{ any::TypeId, collections::HashMap, - fmt::Debug, + fmt::{Debug, DebugStruct}, mem::{size_of, transmute}, string::FromUtf8Error, }; @@ -14,9 +14,9 @@ use crate::{ NfNetlinkDeserializable, NfNetlinkObject, NfNetlinkSerializable, NfNetlinkWriter, }, sys::{ - nlattr, nlmsgerr, nlmsghdr, NFNETLINK_V0, NFNL_MSG_BATCH_BEGIN, NFNL_MSG_BATCH_END, - NFNL_SUBSYS_NFTABLES, NLA_TYPE_MASK, NLMSG_ALIGNTO, NLMSG_DONE, NLMSG_ERROR, - NLMSG_MIN_TYPE, NLMSG_NOOP, NLM_F_DUMP_INTR, + nfgenmsg, nlattr, nlmsgerr, nlmsghdr, NFNETLINK_V0, NFNL_MSG_BATCH_BEGIN, + NFNL_MSG_BATCH_END, NFNL_SUBSYS_NFTABLES, NLA_TYPE_MASK, NLMSG_ALIGNTO, NLMSG_DONE, + NLMSG_ERROR, NLMSG_MIN_TYPE, NLMSG_NOOP, NLM_F_DUMP_INTR, }, InvalidProtocolFamily, ProtoFamily, }; @@ -53,6 +53,9 @@ pub enum DecodeError { #[error("Invalid attribute type")] InvalidAttributeType, + #[error("Invalid type for a chain")] + UnknownChainType, + #[error("Unsupported attribute type")] UnsupportedAttributeType(u16), @@ -89,14 +92,6 @@ pub const fn pad_netlink_object<T>() -> usize { pad_netlink_object_with_variable_size(size) } -#[repr(C)] -#[derive(Debug, Clone, Copy)] -pub struct Nfgenmsg { - pub family: u8, /* AF_xxx */ - pub version: u8, /* nfnetlink version */ - pub res_id: u16, /* resource id */ -} - pub fn get_subsystem_from_nlmsghdr_type(x: u16) -> u8 { ((x & 0xff00) >> 8) as u8 } @@ -126,12 +121,12 @@ pub fn get_nlmsghdr(buf: &[u8]) -> Result<nlmsghdr, DecodeError> { Ok(nlmsghdr) } -#[derive(Debug)] +#[derive(Debug, Clone, PartialEq)] pub enum NlMsg<'a> { Done, Noop, Error(nlmsgerr), - NfGenMsg(Nfgenmsg, &'a [u8]), + NfGenMsg(nfgenmsg, &'a [u8]), } pub fn parse_nlmsg<'a>(buf: &'a [u8]) -> Result<(nlmsghdr, NlMsg<'a>), DecodeError> { @@ -173,14 +168,14 @@ pub fn parse_nlmsg<'a>(buf: &'a [u8]) -> Result<(nlmsghdr, NlMsg<'a>), DecodeErr } } - let size_of_nfgenmsg = pad_netlink_object::<Nfgenmsg>(); + let size_of_nfgenmsg = pad_netlink_object::<nfgenmsg>(); if hdr.nlmsg_len as usize > buf.len() || (hdr.nlmsg_len as usize) < size_of_hdr + size_of_nfgenmsg { return Err(DecodeError::NlMsgTooSmall); } - let nfgenmsg_ptr = buf[size_of_hdr..size_of_hdr + size_of_nfgenmsg].as_ptr() as *const Nfgenmsg; + let nfgenmsg_ptr = buf[size_of_hdr..size_of_hdr + size_of_nfgenmsg].as_ptr() as *const nfgenmsg; let nfgenmsg = unsafe { *nfgenmsg_ptr }; if nfgenmsg.version != NFNETLINK_V0 as u8 { @@ -302,7 +297,11 @@ impl NfNetlinkAttribute for String { } impl NfNetlinkDeserializable for String { - fn deserialize(buf: &[u8]) -> Result<(Self, &[u8]), DecodeError> { + fn deserialize(mut buf: &[u8]) -> Result<(Self, &[u8]), DecodeError> { + // ignore the NULL byte terminator, if any + if buf.len() > 0 && buf[buf.len() - 1] == 0 { + buf = &buf[..buf.len() - 1]; + } Ok((String::from_utf8(buf.to_vec())?, &[])) } } @@ -394,7 +393,7 @@ impl<'a> NfNetlinkAttributeReader<'a> { ) { Ok(x) => self.attrs.set_attr(nla_type, x), Err(DecodeError::UnsupportedAttributeType(t)) => info!( - "Ignore attribute type {} for type id {:?}", + "Ignore attribute type {} for type identified by {:?}", t, TypeId::of::<T>() ), @@ -413,26 +412,6 @@ impl<'a> NfNetlinkAttributeReader<'a> { } } -pub fn parse_object<'a>( - hdr: nlmsghdr, - msg: NlMsg<'a>, - buf: &'a [u8], -) -> Result<(Nfgenmsg, NfNetlinkAttributeReader<'a>, &'a [u8]), DecodeError> { - let remaining_size = hdr.nlmsg_len as usize - - pad_netlink_object_with_variable_size(size_of::<nlmsghdr>() + size_of::<Nfgenmsg>()); - - let remaining_data = &buf[pad_netlink_object_with_variable_size(hdr.nlmsg_len as usize)..]; - - match msg { - NlMsg::NfGenMsg(nfgenmsg, content) => Ok(( - nfgenmsg, - NfNetlinkAttributeReader::new(content, remaining_size)?, - remaining_data, - )), - _ => Err(DecodeError::UnexpectedType(hdr.nlmsg_type)), - } -} - impl NfNetlinkSerializable for NfNetlinkAttributes { fn serialize<'a>(&self, writer: &mut NfNetlinkWriter<'a>) { // TODO: improve performance by not sorting this @@ -485,6 +464,13 @@ macro_rules! impl_attribute_holder { }; } +pub trait InnerFormat { + fn inner_format_struct<'a, 'b: 'a>( + &'a self, + s: DebugStruct<'a, 'b>, + ) -> Result<DebugStruct<'a, 'b>, std::fmt::Error>; +} + impl_attribute_holder!( AttributeType, [String, String], @@ -539,5 +525,58 @@ macro_rules! impl_attr_getters_and_setters { } } } + + + impl $crate::parser::InnerFormat for $struct { + fn inner_format_struct<'a, 'b: 'a>(&'a self, mut s: std::fmt::DebugStruct<'a, 'b>) -> Result<std::fmt::DebugStruct<'a, 'b>, std::fmt::Error> { + $( + // Rewrite attributes names to be readable: 'sys::NFTA_CHAIN_NAME' -> 'name' + // Performance must be terrible, but this is the Debug impl anyway, so that + // must mean we can afford to be slow, right? ;) + if let Some(val) = self.$getter_name() { + let mut attr = stringify!($attr_name); + if let Some((nfta_idx, _match )) = attr.rmatch_indices("NFTA_").next() { + if let Some(underscore_idx) = &attr[nfta_idx+5..].find('_') { + attr = &attr[nfta_idx+underscore_idx+6..]; + } + } + let attr = attr.to_lowercase(); + s.field(&attr, val); + } + )+ + Ok(s) + } + } }; } + +pub fn parse_object<T: AttributeDecoder + 'static>( + buf: &[u8], + add_obj: u32, + del_obj: u32, +) -> Result<(NfNetlinkAttributes, nfgenmsg, &[u8]), DecodeError> { + let (hdr, msg) = parse_nlmsg(buf)?; + + let op = get_operation_from_nlmsghdr_type(hdr.nlmsg_type) as u32; + + if op != add_obj && op != del_obj { + return Err(DecodeError::UnexpectedType(hdr.nlmsg_type)); + } + + let obj_size = hdr.nlmsg_len as usize + - pad_netlink_object_with_variable_size(size_of::<nlmsghdr>() + size_of::<nfgenmsg>()); + + let remaining_data_offset = pad_netlink_object_with_variable_size(hdr.nlmsg_len as usize); + let remaining_data = &buf[remaining_data_offset..]; + + let (nfgenmsg, attrs) = match msg { + NlMsg::NfGenMsg(nfgenmsg, content) => { + (nfgenmsg, NfNetlinkAttributeReader::new(content, obj_size)?) + } + _ => return Err(DecodeError::UnexpectedType(hdr.nlmsg_type)), + }; + + let inner = attrs.decode::<T>()?; + + Ok((inner, nfgenmsg, remaining_data)) +} |