diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/vrrpv2.rs | 255 |
1 files changed, 137 insertions, 118 deletions
diff --git a/src/vrrpv2.rs b/src/vrrpv2.rs index f8f1521..8c2d7d6 100644 --- a/src/vrrpv2.rs +++ b/src/vrrpv2.rs @@ -1,48 +1,36 @@ -use nom::bits::{bits, streaming::take}; -use nom::combinator::map_res; -use nom::error::{Error, ErrorKind}; +//! Parser recognising a VRRP v2 packet. +use nom::error::Error; use nom::multi::count; use nom::number::complete::{be_u16, be_u32, u8}; -use nom::sequence::tuple; -use nom::{Err, IResult}; +use nom::{bits::complete::take, IResult}; use std::net::Ipv4Addr; -const VRRP_REQUIRED_VERSION: u8 = 2; -const VRRP_REQUIRED_TYPE: u8 = 1; // Advertisement - -#[derive(Debug, Clone, PartialEq)] -pub enum VRRPv2Error { - VRRPv2ParseError, -} - -type NomError<'a> = nom::Err<nom::error::Error<&'a [u8]>>; -impl From<NomError<'_>> for VRRPv2Error { - fn from(_: NomError) -> Self { - Self::VRRPv2ParseError - } -} - -#[derive(Debug, PartialEq)] -pub enum VRRPVersion { - V2, -} - -#[derive(Debug, PartialEq)] -pub enum VRRPv2Type { - VRRPv2Advertisement, -} - -#[derive(Debug, PartialEq)] -pub enum VRRPv2AuthType { - VRRPv2AuthNoAuth = 0x00, - VRRPv2AuthReserved1 = 0x01, - VRRPv2AuthReserved2 = 0x02, -} - +type BitInput<'a> = (&'a [u8], usize); + +/// A VRRP version 2 packet. +/// +/// Packet format +/// +/// 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +/// |Version| Type | Virtual Rtr ID| Priority | Count IP Addrs| +/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +/// | Auth Type | Adver Int | Checksum | +/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +/// | IP Address (1) | +/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +/// | . | +/// | . | +/// | . | +/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +/// | IP Address (n) | +/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +/// | Authentication Data (1) | +/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +/// | Authentication Data (2) | +/// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ #[derive(Debug, PartialEq)] pub struct VRRPv2 { - pub version: VRRPVersion, - pub type_: VRRPv2Type, pub virtual_router_id: u8, pub priority: u8, pub count_ip_addrs: u8, @@ -52,55 +40,79 @@ pub struct VRRPv2 { pub ip_addrs: Vec<Ipv4Addr>, } -fn two_nibbles(input: &[u8]) -> IResult<&[u8], (u8, u8)> { - bits::<_, _, Error<(&[u8], usize)>, _, _>(tuple((take(4usize), take(4usize))))(input) +#[derive(Debug, Clone, PartialEq)] +pub enum VRRPv2Error { + InvalidAuthType, + InvalidChecksum, + InvalidType, + InvalidVersion, + ParseError, } -fn parse_version_type(input: &[u8]) -> IResult<&[u8], (VRRPVersion, VRRPv2Type)> { - let (input, pair) = two_nibbles(input)?; - match pair { - (VRRP_REQUIRED_VERSION, VRRP_REQUIRED_TYPE) => { - Ok((input, (VRRPVersion::V2, VRRPv2Type::VRRPv2Advertisement))) - } - _ => Err(Err::Error(Error::new(input, ErrorKind::Alt))), - } +#[derive(Debug, PartialEq)] +pub enum VRRPv2AuthType { + VRRPv2AuthNoAuth = 0x00, + VRRPv2AuthReserved1 = 0x01, + VRRPv2AuthReserved2 = 0x02, } -fn parse_auth_type(input: &[u8]) -> IResult<&[u8], VRRPv2AuthType> { - map_res(u8, |auth_type| { - Ok(match auth_type { - 0 => VRRPv2AuthType::VRRPv2AuthNoAuth, - 1 => VRRPv2AuthType::VRRPv2AuthReserved1, - 2 => VRRPv2AuthType::VRRPv2AuthReserved2, - _ => return Err(Err::Error(Error::new(input, ErrorKind::Alt))), - }) - })(input) +/// Helper function to let compiler infer generic parameters. +fn take_nibble(input: BitInput) -> IResult<BitInput, u8> { + take(4usize)(input) } -fn parse(input: &[u8]) -> IResult<&[u8], VRRPv2> { - let (input, (version, type_)) = parse_version_type(input)?; - let (input, virtual_router_id) = u8(input)?; - let (input, priority) = u8(input)?; - let (input, count_ip_addrs) = u8(input)?; - let (input, auth_type) = parse_auth_type(input)?; - let (input, advertisement_interval) = u8(input)?; - let (input, checksum) = be_u16(input)?; - let (input, xs) = count(be_u32, usize::from(count_ip_addrs))(input)?; - let ip_addrs = xs.into_iter().map(Ipv4Addr::from).collect(); - Ok(( - input, - VRRPv2 { - version, - type_, - virtual_router_id, - priority, - count_ip_addrs, - auth_type, - advertisement_interval, - checksum, - ip_addrs, - }, - )) +fn parse(input: &[u8]) -> Result<VRRPv2, VRRPv2Error> { + let Ok(((input, _), version)) = take_nibble((input, 0)) else { + return Err(VRRPv2Error::ParseError); + }; + if version != 2 { + return Err(VRRPv2Error::InvalidVersion); + } + let Ok(((input, _), type_)) = take_nibble((input, 4)) else { + return Err(VRRPv2Error::ParseError); + }; + //Advertisement + if type_ != 1 { + return Err(VRRPv2Error::InvalidType); + } + let Ok((input, virtual_router_id)) = u8::<&[u8], Error<&[u8]>>(input) else { + return Err(VRRPv2Error::ParseError); + }; + let Ok((input, priority)) = u8::<&[u8], Error<&[u8]>>(input) else { + return Err(VRRPv2Error::ParseError); + }; + let Ok((input, count_ip_addrs)) = u8::<&[u8], Error<&[u8]>>(input) else { + return Err(VRRPv2Error::ParseError); + }; + let Ok((input, auth_type)) = u8::<&[u8], Error<&[u8]>>(input) else { + return Err(VRRPv2Error::ParseError); + }; + let auth_type = match auth_type { + 0 => VRRPv2AuthType::VRRPv2AuthNoAuth, + 1 => VRRPv2AuthType::VRRPv2AuthReserved1, + 2 => VRRPv2AuthType::VRRPv2AuthReserved2, + _ => return Err(VRRPv2Error::InvalidAuthType), + }; + let Ok((input, advertisement_interval)) = u8::<&[u8], Error<&[u8]>>(input) else { + return Err(VRRPv2Error::ParseError); + }; + let Ok((input, checksum)) = be_u16::<&[u8], Error<&[u8]>>(input) else { + return Err(VRRPv2Error::ParseError); + }; + let Ok((_, xs)) = count(be_u32::<&[u8], Error<&[u8]>>, usize::from(count_ip_addrs))(input) + else { + return Err(VRRPv2Error::ParseError); + }; + let ip_addrs: Vec<Ipv4Addr> = xs.into_iter().map(Ipv4Addr::from).collect(); + Ok(VRRPv2 { + virtual_router_id, + priority, + count_ip_addrs, + auth_type, + advertisement_interval, + checksum, + ip_addrs, + }) } // Nightly has a nicer array_chunks API to express it more succinctly. @@ -127,54 +139,65 @@ fn validate_checksum(bytes: &[u8]) -> bool { checksum == 0 } +/// Parse and validate a byte array to construct a VRRPv2 struct. +/// +/// # Examples +/// +/// ``` +/// use vrrpd::vrrpv2::VRRPv2; +/// use vrrpd::vrrpv2::VRRPv2AuthType; +/// use vrrpd::vrrpv2::from_bytes; +/// use std::net::Ipv4Addr; +/// +/// let bytes = [ +/// 0x21, 0x01, 0x64, 0x01, 0x00, 0x01, 0xba, 0x52, 0xc0, 0xa8, 0x00, 0x01, 0x00, 0x00, 0x00, +/// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, +/// ]; +/// let expected = VRRPv2 { +/// virtual_router_id: 1, +/// priority: 100, +/// count_ip_addrs: 1, +/// auth_type: VRRPv2AuthType::VRRPv2AuthNoAuth, +/// checksum: 47698, +/// advertisement_interval: 1, +/// ip_addrs: vec![Ipv4Addr::from([192, 168, 0, 1])], +/// }; +/// assert_eq!(from_bytes(&bytes), Ok(expected)); +/// ``` pub fn from_bytes(bytes: &[u8]) -> Result<VRRPv2, VRRPv2Error> { + let vrrpv2 = parse(bytes)?; if !validate_checksum(bytes) { - return Err(VRRPv2Error::VRRPv2ParseError); - } - match parse(bytes) { - Ok((_, v)) => Ok(v), - Err(e) => Err(e.into()), + return Err(VRRPv2Error::InvalidChecksum); } + Ok(vrrpv2) } #[test] -fn test_standard_bytes() { - let bytes = [ - 0x21, 0x01, 0x64, 0x01, 0x00, 0x01, 0xba, 0x52, 0xc0, 0xa8, 0x00, 0x01, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, - ]; - let got = from_bytes(&bytes).unwrap(); - let expected = VRRPv2 { - version: VRRPVersion::V2, - type_: VRRPv2Type::VRRPv2Advertisement, - virtual_router_id: 1, - priority: 100, - count_ip_addrs: 1, - auth_type: VRRPv2AuthType::VRRPv2AuthNoAuth, - checksum: 47698, - advertisement_interval: 1, - ip_addrs: vec![Ipv4Addr::from([192, 168, 0, 1])], - }; - assert_eq!(got, expected); +fn test_incomplete_bytes() { + let bytes = [0x21, 0x01]; + assert_eq!(from_bytes(&bytes), Err(VRRPv2Error::ParseError)); } #[test] -fn test_incomplete_bytes() { - let bytes = [0x21, 0x01]; +fn test_invalid_version() { + let bytes = [ + 0x31, 0x2a, 0x64, 0x1, 0x0, 0x1, 0xaa, 0x29, 0xc0, 0xa8, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, + 0x0, 0x0, 0x0, + ]; let got = from_bytes(&bytes); assert_eq!(got.is_err(), true); - assert_eq!(got.err(), Some(VRRPv2Error::VRRPv2ParseError)); + assert_eq!(got.err(), Some(VRRPv2Error::InvalidVersion)); } #[test] -fn test_invalid_version_type() { +fn test_invalid_type() { let bytes = [ - 0x00, 0x01, 0x64, 0x01, 0x00, 0x01, 0xba, 0x52, 0xc0, 0xa8, 0x00, 0x01, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x20, 0x1, 0x2a, 0x0, 0x0, 0x1, 0xb5, 0xfd, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, + 0x0, 0x0, 0x0, ]; let got = from_bytes(&bytes); assert_eq!(got.is_err(), true); - assert_eq!(got.err(), Some(VRRPv2Error::VRRPv2ParseError)); + assert_eq!(got.err(), Some(VRRPv2Error::InvalidType)); } #[test] @@ -183,9 +206,7 @@ fn test_invalid_auth_type() { 0x21, 0x01, 0x64, 0x01, 0x03, 0x01, 0xba, 0x52, 0xc0, 0xa8, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, ]; - let got = from_bytes(&bytes); - assert_eq!(got.is_err(), true); - assert_eq!(got.err(), Some(VRRPv2Error::VRRPv2ParseError)); + assert_eq!(from_bytes(&bytes), Err(VRRPv2Error::InvalidAuthType)); } #[test] @@ -194,7 +215,5 @@ fn test_invalid_checksum() { 0x21, 0x01, 0x64, 0x01, 0x00, 0x01, 0xbb, 0x52, 0xc0, 0xa8, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, ]; - let got = from_bytes(&bytes); - assert_eq!(got.is_err(), true); - assert_eq!(got.err(), Some(VRRPv2Error::VRRPv2ParseError)); + assert_eq!(from_bytes(&bytes), Err(VRRPv2Error::InvalidChecksum)); } |