--- a/src/vrrpv2.rs Sun Jul 09 02:40:54 2023 +0530
+++ b/src/vrrpv2.rs Thu Dec 28 23:17:24 2023 +0530
@@ -1,35 +1,52 @@
-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
+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 virtual_router_id: u8,
+ pub priority: u8,
+ pub count_ip_addrs: u8,
+ pub auth_type: VRRPv2AuthType,
+ pub advertisement_interval: u8,
+ pub checksum: u16,
+ pub ip_addrs: Vec<Ipv4Addr>,
+}
#[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,
+ InvalidAuthType,
+ InvalidChecksum,
+ InvalidType,
+ InvalidVersion,
+ ParseError,
}
#[derive(Debug, PartialEq)]
@@ -39,68 +56,63 @@
VRRPv2AuthReserved2 = 0x02,
}
-#[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,
- pub auth_type: VRRPv2AuthType,
- pub advertisement_interval: u8,
- pub checksum: u16,
- pub ip_addrs: Vec<Ipv4Addr>,
-}
-
-fn two_nibbles(input: &[u8]) -> IResult<&[u8], (u8, u8)> {
- bits::<_, _, Error<(&[u8], usize)>, _, _>(tuple((take(4usize), take(4usize))))(input)
-}
-
-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))),
- }
+/// Helper function to let compiler infer generic parameters.
+fn take_nibble(input: BitInput) -> IResult<BitInput, u8> {
+ take(4usize)(input)
}
-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)
-}
-
-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 @@
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);
}
-}
-
-#[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);
+ Ok(vrrpv2)
}
#[test]
fn test_incomplete_bytes() {
let bytes = [0x21, 0x01];
- 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::ParseError));
}
#[test]
-fn test_invalid_version_type() {
+fn test_invalid_version() {
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,
+ 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_type() {
+ let bytes = [
+ 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::InvalidType));
}
#[test]
@@ -183,9 +206,7 @@
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 @@
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));
}