1 // Copyright 2021 Ian Jackson and contributors to Hippotat
2 // SPDX-License-Identifier: AGPL-3.0-or-later
3 // There is NO WARRANTY.
7 pub static SLIP_END_SLICE: &[u8] = &[SLIP_END];
10 pub fn check_checkmtu_mimeswap<const TO_MIME: bool>
11 (mtu: u32, data: &mut [u8])
13 // eprintln!("before: {:?}", DumpHex(data));
15 for mut packet in data.split_mut(|&c| c == SLIP_END) {
16 if packet.len() > mtu.sat() {
17 throw!(anyhow!("MTU exceeded ({} > {})", packet.len(), mtu));
20 while let Some((i, was_mime)) = packet.iter().enumerate().find_map(
22 SLIP_MIME_ESC => Some((i,true)),
23 SLIP_ESC => Some((i,false)),
27 packet[i] = if was_mime { SLIP_ESC } else { SLIP_MIME_ESC };
28 if was_mime != TO_MIME {
29 match packet.get(i+1) {
31 Some(&SLIP_ESC_ESC) => Ok(()),
32 _ => Err(anyhow!("SLIP escape not followed by ESC_END or ESC_ESC")),
34 packet = &mut packet[i+2 ..];
36 packet = &mut packet[i+1 ..];
41 // eprintln!(" after: {:?}", DumpHex(data));
44 pub type Frame = Vec<u8>;
45 pub type FramesData = Vec<Vec<u8>>;
53 impl Debug for Frames {
55 fn fmt(&self, f: &mut fmt::Formatter) {
56 write!(f, "Frames{{n={},len={}}}", &self.frames.len(), &self.total_len)?;
62 pub fn add(&mut self, max: u32, frame: Frame) {
63 if frame.len() == 0 { return }
64 let new_total = self.total_len + frame.len() + 1;
65 if new_total > max.sat() { throw!(frame) }
66 self.total_len = new_total;
67 self.frames.push(frame);
71 impl From<Frames> for FramesData {
72 fn from(frames: Frames) -> FramesData { frames.frames }
75 pub fn ip_packet_addrs(packet: &[u8]) -> Option<(IpAddr, IpAddr)> {
76 Some(match packet.get(0)? & 0xf0 {
77 4 if packet.len() >= 20 => (
78 Ipv4Addr::from(*<&[u8;4]>::try_from(&packet[12..16]).unwrap()).into(),
79 Ipv4Addr::from(*<&[u8;4]>::try_from(&packet[16..20]).unwrap()).into(),
82 6 if packet.len() >= 40 => (
83 Ipv6Addr::from(*<&[u8;16]>::try_from(&packet[ 8..24]).unwrap()).into(),
84 Ipv6Addr::from(*<&[u8;16]>::try_from(&packet[24..40]).unwrap()).into(),
91 #[derive(Copy,Clone,Eq,PartialEq,Ord,PartialOrd,Hash)]
92 pub struct DumpHex<'b>(pub &'b [u8]);
93 impl Debug for DumpHex<'_> {
95 fn fmt(&self, f: &mut fmt::Formatter) {
96 for v in self.0 { write!(f, "{:02x}", v)?; }
101 fn mime_slip_to_mime() {
102 fn chk(i: &[u8], exp: Result<&[u8], &str>) {
103 let mut p = i.to_owned();
104 match (exp, check_checkmtu_mimeswap::<true>(10, p.as_mut())) {
105 (Ok(exp), Ok(())) => assert_eq!( DumpHex(exp), DumpHex(&p) ),
106 (Err(exp), Err(got)) => assert!( got.to_string().contains(exp) ),
107 x => panic!("? {:?}", x),
111 chk( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
112 Ok(&[ SLIP_END, b'-', SLIP_ESC_END, SLIP_ESC, b'X' ]) );
114 chk( &[ SLIP_END, SLIP_ESC, b'y' ], Err("SLIP escape") );
116 chk( &[ SLIP_END, b'-', b'y' ],
117 Ok(&[ SLIP_END, SLIP_ESC, b'y' ]) );
119 chk( &[b'x'; 20], Err("MTU"));