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use crate::*;
/// Slice containing laxly parsed the network headers & payloads (e.g. IPv4, IPv6, ARP).
///
/// Compared to the normal [`NetSlice`] this slice allows the
/// payload to be incomplete/cut off and errors to be present in
/// the IpPayload.
///
/// The main usecases for "laxly" parsed slices are are:
///
/// * Parsing packets that have been cut off. This is, for example, useful to
/// parse packets returned via ICMP as these usually only contain the start.
/// * Parsing packets where the `total_len` (for IPv4) or `payload_len` (for IPv6)
/// have not yet been set. This can be useful when parsing packets which have
/// been recorded in a layer before the length field was set (e.g. before the
/// operating system set the length fields).
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum LaxNetSlice<'a> {
/// IPv4 header & the decoded extension headers.
Ipv4(LaxIpv4Slice<'a>),
/// IPv6 header & the decoded extension headers.
Ipv6(LaxIpv6Slice<'a>),
/// "Address Resolution Protocol" Packet,
Arp(ArpPacketSlice<'a>),
}
impl<'a> LaxNetSlice<'a> {
/// Returns a reference to ip payload if the net slice contains
/// an ipv4 or ipv6 slice.
#[inline]
pub fn ip_payload_ref(&self) -> Option<&LaxIpPayloadSlice<'a>> {
match self {
LaxNetSlice::Ipv4(s) => Some(&s.payload),
LaxNetSlice::Ipv6(s) => Some(&s.payload),
LaxNetSlice::Arp(_) => None,
}
}
}
impl<'a> From<LaxIpSlice<'a>> for LaxNetSlice<'a> {
#[inline]
fn from(value: LaxIpSlice<'a>) -> LaxNetSlice<'a> {
match value {
LaxIpSlice::Ipv4(ipv4) => LaxNetSlice::Ipv4(ipv4),
LaxIpSlice::Ipv6(ipv6) => LaxNetSlice::Ipv6(ipv6),
}
}
}
impl<'a> From<LaxIpv4Slice<'a>> for LaxNetSlice<'a> {
#[inline]
fn from(value: LaxIpv4Slice<'a>) -> LaxNetSlice<'a> {
LaxNetSlice::Ipv4(value)
}
}
impl<'a> From<LaxIpv6Slice<'a>> for LaxNetSlice<'a> {
#[inline]
fn from(value: LaxIpv6Slice<'a>) -> LaxNetSlice<'a> {
LaxNetSlice::Ipv6(value)
}
}
#[cfg(test)]
mod tests {
use crate::*;
use alloc::{format, vec::Vec};
#[test]
fn debug() {
let bytes = Ipv6Header {
next_header: IpNumber::UDP,
..Default::default()
}
.to_bytes();
let s = LaxIpv6Slice::from_slice(&bytes).unwrap().0;
let n = LaxNetSlice::Ipv6(s.clone());
assert_eq!(format!("{n:?}"), format!("Ipv6({s:?})"));
}
#[test]
fn clone_eq() {
let bytes = Ipv6Header {
next_header: IpNumber::UDP,
..Default::default()
}
.to_bytes();
let s = LaxNetSlice::Ipv6(LaxIpv6Slice::from_slice(&bytes).unwrap().0);
assert_eq!(s, s.clone())
}
#[test]
fn ip_payload_ref() {
// ipv4
{
let payload = [1, 2, 3, 4];
let bytes = {
let mut bytes = Vec::with_capacity(Ipv4Header::MIN_LEN + 4);
bytes.extend_from_slice(
&(Ipv4Header {
total_len: Ipv4Header::MIN_LEN_U16 + 4,
protocol: IpNumber::UDP,
..Default::default()
})
.to_bytes(),
);
bytes.extend_from_slice(&payload);
bytes
};
let s = LaxNetSlice::Ipv4(LaxIpv4Slice::from_slice(&bytes).unwrap().0);
assert_eq!(
s.ip_payload_ref(),
Some(&LaxIpPayloadSlice {
ip_number: IpNumber::UDP,
fragmented: false,
len_source: LenSource::Ipv4HeaderTotalLen,
payload: &payload,
incomplete: false,
})
);
}
// ipv6
{
let payload = [1, 2, 3, 4];
let bytes = {
let mut bytes = Vec::with_capacity(Ipv6Header::LEN + 4);
bytes.extend_from_slice(
&(Ipv6Header {
next_header: IpNumber::UDP,
payload_length: 4,
..Default::default()
})
.to_bytes(),
);
bytes.extend_from_slice(&payload);
bytes
};
let s = LaxNetSlice::Ipv6(LaxIpv6Slice::from_slice(&bytes).unwrap().0);
assert_eq!(
s.ip_payload_ref(),
Some(&LaxIpPayloadSlice {
ip_number: IpNumber::UDP,
fragmented: false,
len_source: LenSource::Ipv6HeaderPayloadLen,
payload: &payload,
incomplete: false,
})
);
}
}
#[test]
fn from() {
// IpSlice::Ipv4
{
let payload = [1, 2, 3, 4];
let bytes = {
let mut bytes = Vec::with_capacity(Ipv4Header::MIN_LEN + 4);
bytes.extend_from_slice(
&(Ipv4Header {
total_len: Ipv4Header::MIN_LEN_U16 + 4,
protocol: IpNumber::UDP,
..Default::default()
})
.to_bytes(),
);
bytes.extend_from_slice(&payload);
bytes
};
let i = LaxIpv4Slice::from_slice(&bytes).unwrap().0;
let actual: LaxNetSlice = LaxIpSlice::Ipv4(i.clone()).into();
assert_eq!(LaxNetSlice::Ipv4(i.clone()), actual);
}
// LaxIpv4Slice
{
let payload = [1, 2, 3, 4];
let bytes = {
let mut bytes = Vec::with_capacity(Ipv4Header::MIN_LEN + 4);
bytes.extend_from_slice(
&(Ipv4Header {
total_len: Ipv4Header::MIN_LEN_U16 + 4,
protocol: IpNumber::UDP,
..Default::default()
})
.to_bytes(),
);
bytes.extend_from_slice(&payload);
bytes
};
let i = LaxIpv4Slice::from_slice(&bytes).unwrap().0;
let actual: LaxNetSlice = i.clone().into();
assert_eq!(LaxNetSlice::Ipv4(i.clone()), actual);
}
// IpSlice::Ipv6
{
let payload = [1, 2, 3, 4];
let bytes = {
let mut bytes = Vec::with_capacity(Ipv6Header::LEN + 4);
bytes.extend_from_slice(
&(Ipv6Header {
next_header: IpNumber::UDP,
payload_length: 4,
..Default::default()
})
.to_bytes(),
);
bytes.extend_from_slice(&payload);
bytes
};
let i = LaxIpv6Slice::from_slice(&bytes).unwrap().0;
let actual: LaxNetSlice = i.clone().into();
assert_eq!(LaxNetSlice::Ipv6(i.clone()), actual);
}
}
}