1 // Copyright 2021 Ian Jackson and contributors to Hippotat
2 // SPDX-License-Identifier: GPL-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("truncated, IPv{vsn}, len={len}")] Truncated { len: usize, vsn: u8 },
19 pub trait SlipMime { const CONV_TO: Option<bool>; }
20 #[derive(Copy,Clone,Debug)] pub struct Slip2Mime;
21 #[derive(Copy,Clone,Debug)] pub struct Mime2Slip;
22 #[derive(Copy,Clone,Debug)] pub struct SlipNoConv;
23 impl SlipMime for Slip2Mime { const CONV_TO: Option<bool> = Some(true); }
24 impl SlipMime for Mime2Slip { const CONV_TO: Option<bool> = Some(false); }
25 impl SlipMime for SlipNoConv { const CONV_TO: Option<bool> = None; }
29 #[error("only bad IP datagrams")]
30 pub struct ErrorOnlyBad;
32 #[throws(ErrorOnlyBad)]
33 pub fn checkn<AC, EH, OUT, ACR, M: SlipMime+Copy>(
40 ) where AC: Fn(&[u8]) -> Result<ACR, PacketError> + Copy,
41 OUT: FnMut((Box<[u8]>, ACR)) -> Result<(), PacketError>,
42 EH: FnMut(PacketError),
44 // eprintln!("before: {:?}", DumpHex(data));
45 if data.is_empty() { return }
48 for packet in data.split(|&c| c == SLIP_END) {
50 let checked = check1(mime, mtu, packet, addr_chk);
51 if matches!(checked, Err(PacketError::Empty)) { return Ok::<_,PE>(()) }
57 Err(e) => { err=true; error_handler(e); },
60 // eprintln!(" after: {:?}", DumpHex(data));
61 if err && !ok { throw!(ErrorOnlyBad) }
64 #[throws(PacketError)]
65 pub fn check1<AC, M: SlipMime, ACR>(
71 where AC: Fn(&[u8]) -> Result<ACR, PacketError>,
73 if packet.len() == 0 {
74 throw!(PacketError::Empty)
77 let mut packet: Box<[u8]> = packet.to_owned().into();
78 let mut walk: &mut [u8] = &mut packet;
79 let mut header = [0u8; HEADER_FOR_ADDR];
80 let mut wheader = &mut header[..];
83 while let Some((i, was_mime)) = walk.iter().enumerate().find_map(
85 SLIP_ESC => Some((i,false)),
86 SLIP_MIME_ESC if M::CONV_TO.is_some() => Some((i,true)),
90 let _ = wheader.write(&walk[0..i]);
91 if M::CONV_TO.is_some() {
92 walk[i] = if was_mime { SLIP_ESC } else { SLIP_MIME_ESC };
94 if Some(was_mime) != M::CONV_TO {
95 let c = match walk.get(i+1) {
96 Some(&SLIP_ESC_ESC) => SLIP_ESC,
97 Some(&SLIP_ESC_END) => SLIP_END,
98 _ => throw!(PacketError::SLIP),
100 let _ = wheader.write(&[c]);
101 walk = &mut walk[i+2 ..];
104 let _ = wheader.write(&[SLIP_MIME_ESC]);
105 walk = &mut walk[i+1 ..];
108 let _ = wheader.write(walk);
109 let wheader_len = wheader.len();
110 let header = &header[0.. header.len() - wheader_len];
112 let decoded_len = packet.len() - escapes;
113 if decoded_len > mtu.sat() {
114 throw!(PacketError::MTU { len: decoded_len, mtu });
117 let acr = addr_chk(&header)?;
122 pub type Frame = Vec<u8>;
123 pub type FramesData = Vec<Vec<u8>>;
124 // todo: https://github.com/tokio-rs/bytes/pull/504
125 // pub type Frame = Box<[u8]>;
126 // pub type FramesData = Vec<Frame>;
127 // `From<Box<[u8]>>` is not implemented for `Bytes`
128 // when this is fixed, there are two `into`s in client.rs which
129 // become redundant (search for todo:504)
139 impl Debug for Frames {
140 #[throws(fmt::Error)]
141 fn fmt(&self, f: &mut fmt::Formatter) {
142 write!(f, "Frames{{n={},len={}}}", &self.frames.len(), &self.total_len)?;
148 pub fn add(&mut self, max: u32, frame: Frame) {
149 if frame.len() == 0 { return }
150 let new_total = self.total_len + frame.len() + 1;
151 if new_total > max.sat() { self.tried_full = true; throw!(frame); }
152 self.total_len = new_total;
153 self.frames.push(frame);
156 #[inline] pub fn tried_full(&self) -> bool { self.tried_full }
157 #[inline] pub fn is_empty(&self) -> bool { self.frames.is_empty() }
160 impl From<Frames> for FramesData {
161 fn from(frames: Frames) -> FramesData { frames.frames }
164 const HEADER_FOR_ADDR: usize = 40;
166 #[throws(PacketError)]
167 pub fn ip_packet_addr<const DST: bool>(packet: &[u8]) -> IpAddr {
168 let vsn = (packet.get(0).ok_or_else(|| PE::Empty)? & 0xf0) >> 4;
170 4 if packet.len() >= 20 => {
171 let slice = &packet[if DST { 16 } else { 12 }..][0..4];
172 Ipv4Addr::from(*<&[u8;4]>::try_from(slice).unwrap()).into()
175 6 if packet.len() >= 40 => {
176 let slice = &packet[if DST { 24 } else { 8 }..][0..16];
177 Ipv6Addr::from(*<&[u8;16]>::try_from(slice).unwrap()).into()
180 _ => throw!(PE::Truncated{ vsn, len: packet.len() }),
184 #[derive(Copy,Clone,Eq,PartialEq,Ord,PartialOrd,Hash)]
185 pub struct DumpHex<'b>(pub &'b [u8]);
186 impl Debug for DumpHex<'_> {
187 #[throws(fmt::Error)]
188 fn fmt(&self, f: &mut fmt::Formatter) {
189 for v in self.0 { write!(f, "{:02x}", v)?; }
190 match str::from_utf8(self.0) {
191 Ok(s) => write!(f, "={:?}", s)?,
192 Err(x) => write!(f, "={:?}..",
193 str::from_utf8(&self.0[0..x.valid_up_to()]).unwrap()
200 fn mime_slip_to_mime() {
201 use PacketError as PE;
204 fn chk<M: SlipMime>(i: &[u8], exp_p: &[&[u8]], exp_e: &[PacketError]) {
205 dbg!(M::CONV_TO, DumpHex(i));
206 let mut got_e = vec![];
207 let mut got_p = vec![];
208 check::<_,_,_,M>(MTU, i, &mut got_p, |_|Ok(()), |e| got_e.push(e));
209 assert_eq!( got_p.iter().map(|b| DumpHex(b)).collect_vec(),
210 exp_p.iter().map(|b| DumpHex(b)).collect_vec() );
216 ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
217 &[ &[ b'-', SLIP_ESC_END, SLIP_ESC, b'X' ] ],
221 ( &[ SLIP_END, SLIP_ESC, b'y' ], &[],
222 &[ PE::Empty, PE::SLIP ]);
225 ( &[ SLIP_END, b'-', b'y' ],
226 &[ &[ SLIP_ESC, b'y' ] ],
232 &[ PE::MTU { len: 20, mtu: MTU } ]);
235 ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
236 &[ &[ SLIP_ESC, SLIP_ESC_END, b'-', b'X' ] ],