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];
9 #[derive(Error,Debug,Copy,Clone,Eq,PartialEq)]
10 pub enum PacketError {
11 #[error("empty packet")] Empty,
12 #[error("MTU exceeded ({len} > {mtu})")] MTU { len: usize, mtu: u32 },
13 #[error("Invalid SLIP escape sequence")] SLIP,
14 #[error("unexpected src addr {0:?}")] Src(IpAddr),
15 #[error("unexpected dst addr {0:?}")] Dst(IpAddr),
16 #[error("bad, IPv{vsn}, len={len}")] Bad { len: usize, vsn: u8 },
19 pub fn check<AC, EH, const TO_MIME: bool>
20 (mtu: u32, data: &[u8], mut addr_chk: AC, mut error_handler: EH)
22 where AC: FnMut(&[u8]) -> Result<(), PacketError>,
23 EH: FnMut(PacketError),
25 // eprintln!("before: {:?}", DumpHex(data));
29 for packet in data.split(|&c| c == SLIP_END) {
31 if packet.len() == 0 {
32 throw!(PacketError::Empty)
34 if packet.len() > mtu.sat() {
35 throw!(PacketError::MTU { len: packet.len(), mtu });
38 let mut packet: Box<[u8]> = packet.to_owned().into();
39 let mut walk: &mut [u8] = &mut packet;
40 let mut header = [0u8; HEADER_FOR_ADDR];
41 let mut wheader = &mut header[..];
43 while let Some((i, was_mime)) = walk.iter().enumerate().find_map(
45 SLIP_MIME_ESC => Some((i,true)),
46 SLIP_ESC => Some((i,false)),
50 let _ = wheader.write(&walk[0..i]);
51 walk[i] = if was_mime { SLIP_ESC } else { SLIP_MIME_ESC };
52 if was_mime != TO_MIME {
53 let c = match walk.get(i+1) {
54 Some(&SLIP_ESC_END) => SLIP_ESC,
55 Some(&SLIP_ESC_ESC) => SLIP_END,
56 _ => throw!(PacketError::SLIP),
58 let _ = wheader.write(&[c]);
59 walk = &mut walk[i+2 ..];
61 let _ = wheader.write(&[SLIP_MIME_ESC]);
62 walk = &mut walk[i+1 ..];
65 let _ = wheader.write(walk);
71 Err(e) => error_handler(e),
72 Ok(packet) => out.push(packet),
76 // eprintln!(" after: {:?}", DumpHex(data));
79 pub type Frame = Vec<u8>;
80 pub type FramesData = Vec<Vec<u8>>;
81 //pub type Frame = Box<[u8]>;
82 //pub type FramesData = Vec<Frame>;
83 // `From<Box<[u8]>>` is not implemented for `Bytes`
93 impl Debug for Frames {
95 fn fmt(&self, f: &mut fmt::Formatter) {
96 write!(f, "Frames{{n={},len={}}}", &self.frames.len(), &self.total_len)?;
102 pub fn add(&mut self, max: u32, frame: Frame) {
103 if frame.len() == 0 { return }
104 let new_total = self.total_len + frame.len() + 1;
105 if new_total > max.sat() { self.tried_full = true; throw!(frame); }
106 self.total_len = new_total;
107 self.frames.push(frame);
110 #[inline] pub fn tried_full(&self) -> bool { self.tried_full }
111 #[inline] pub fn is_empty(&self) -> bool { self.frames.is_empty() }
114 impl From<Frames> for FramesData {
115 fn from(frames: Frames) -> FramesData { frames.frames }
118 const HEADER_FOR_ADDR: usize = 40;
120 #[throws(PacketError)]
121 pub fn ip_packet_addr<const DST: bool>(packet: &[u8]) -> IpAddr {
122 let vsn = (packet.get(0).ok_or_else(|| PE::Empty)? & 0xf0) >> 4;
124 4 if packet.len() >= 20 => {
125 let slice = &packet[if DST { 16 } else { 12 }..][0..4];
126 Ipv4Addr::from(*<&[u8;4]>::try_from(slice).unwrap()).into()
129 6 if packet.len() >= 40 => {
130 let slice = &packet[if DST { 24 } else { 8 }..][0..16];
131 Ipv6Addr::from(*<&[u8;16]>::try_from(slice).unwrap()).into()
134 _ => throw!(PE::Bad{ vsn, len: packet.len() }),
138 #[derive(Copy,Clone,Eq,PartialEq,Ord,PartialOrd,Hash)]
139 pub struct DumpHex<'b>(pub &'b [u8]);
140 impl Debug for DumpHex<'_> {
141 #[throws(fmt::Error)]
142 fn fmt(&self, f: &mut fmt::Formatter) {
143 for v in self.0 { write!(f, "{:02x}", v)?; }
148 fn mime_slip_to_mime() {
149 use PacketError as PE;
152 fn chk(i: &[u8], exp_p: &[&[u8]], exp_e: &[PacketError]) {
153 let mut got_e = vec![];
154 let got_p = check::<_,_,true>(MTU, i, |_|Ok(()), |e| got_e.push(e));
155 assert_eq!( got_p.iter().map(|b| DumpHex(b)).collect_vec(),
156 exp_p.iter().map(|b| DumpHex(b)).collect_vec() );
161 chk( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
162 &[ &[ b'-', SLIP_ESC_END, SLIP_ESC, b'X' ] ],
165 chk( &[ SLIP_END, SLIP_ESC, b'y' ], &[],
166 &[ PE::Empty, PE::SLIP ]);
168 chk( &[ SLIP_END, b'-', b'y' ],
169 &[ &[ SLIP_ESC, b'y' ] ],
174 &[ PE::MTU { len: 20, mtu: MTU } ]);