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; }
28 pub struct ErrorOnlyBad;
30 #[throws(ErrorOnlyBad)]
31 pub fn checkn<AC, EH, OUT, M: SlipMime+Copy>(
38 ) where AC: Fn(&[u8]) -> Result<(), PacketError> + Copy,
39 OUT: FnMut(Box<[u8]>) -> Result<(), PacketError>,
40 EH: FnMut(PacketError),
42 // eprintln!("before: {:?}", DumpHex(data));
43 if data.is_empty() { return }
46 for packet in data.split(|&c| c == SLIP_END) {
48 let checked = check1(mime, mtu, packet, addr_chk);
49 if matches!(checked, Err(PacketError::Empty)) { return Ok::<_,PE>(()) }
50 let (packet, _acr) = checked?;
56 Err(e) => { err=true; error_handler(e); },
59 // eprintln!(" after: {:?}", DumpHex(data));
60 if err && !ok { throw!(ErrorOnlyBad) }
63 #[throws(PacketError)]
64 pub fn check1<AC, M: SlipMime, ACR>(
70 where AC: Fn(&[u8]) -> Result<ACR, PacketError>,
72 if packet.len() == 0 {
73 throw!(PacketError::Empty)
76 let mut packet: Box<[u8]> = packet.to_owned().into();
77 let mut walk: &mut [u8] = &mut packet;
78 let mut header = [0u8; HEADER_FOR_ADDR];
79 let mut wheader = &mut header[..];
82 while let Some((i, was_mime)) = walk.iter().enumerate().find_map(
84 SLIP_ESC => Some((i,false)),
85 SLIP_MIME_ESC if M::CONV_TO.is_some() => Some((i,true)),
89 let _ = wheader.write(&walk[0..i]);
90 if M::CONV_TO.is_some() {
91 walk[i] = if was_mime { SLIP_ESC } else { SLIP_MIME_ESC };
93 if Some(was_mime) != M::CONV_TO {
94 let c = match walk.get(i+1) {
95 Some(&SLIP_ESC_ESC) => SLIP_ESC,
96 Some(&SLIP_ESC_END) => SLIP_END,
97 _ => throw!(PacketError::SLIP),
99 let _ = wheader.write(&[c]);
100 walk = &mut walk[i+2 ..];
103 let _ = wheader.write(&[SLIP_MIME_ESC]);
104 walk = &mut walk[i+1 ..];
107 let _ = wheader.write(walk);
108 let wheader_len = wheader.len();
109 let header = &header[0.. header.len() - wheader_len];
111 let decoded_len = packet.len() - escapes;
112 if decoded_len > mtu.sat() {
113 throw!(PacketError::MTU { len: decoded_len, mtu });
116 let acr = addr_chk(&header)?;
121 pub type Frame = Vec<u8>;
122 pub type FramesData = Vec<Vec<u8>>;
123 // todo: https://github.com/tokio-rs/bytes/pull/504
124 // pub type Frame = Box<[u8]>;
125 // pub type FramesData = Vec<Frame>;
126 // `From<Box<[u8]>>` is not implemented for `Bytes`
127 // when this is fixed, there are two `into`s in client.rs which
128 // become redundant (search for todo:504)
138 impl Debug for Frames {
139 #[throws(fmt::Error)]
140 fn fmt(&self, f: &mut fmt::Formatter) {
141 write!(f, "Frames{{n={},len={}}}", &self.frames.len(), &self.total_len)?;
147 pub fn add(&mut self, max: u32, frame: Frame) {
148 if frame.len() == 0 { return }
149 let new_total = self.total_len + frame.len() + 1;
150 if new_total > max.sat() { self.tried_full = true; throw!(frame); }
151 self.total_len = new_total;
152 self.frames.push(frame);
155 #[inline] pub fn tried_full(&self) -> bool { self.tried_full }
156 #[inline] pub fn is_empty(&self) -> bool { self.frames.is_empty() }
159 impl From<Frames> for FramesData {
160 fn from(frames: Frames) -> FramesData { frames.frames }
163 const HEADER_FOR_ADDR: usize = 40;
165 #[throws(PacketError)]
166 pub fn ip_packet_addr<const DST: bool>(packet: &[u8]) -> IpAddr {
167 let vsn = (packet.get(0).ok_or_else(|| PE::Empty)? & 0xf0) >> 4;
169 4 if packet.len() >= 20 => {
170 let slice = &packet[if DST { 16 } else { 12 }..][0..4];
171 Ipv4Addr::from(*<&[u8;4]>::try_from(slice).unwrap()).into()
174 6 if packet.len() >= 40 => {
175 let slice = &packet[if DST { 24 } else { 8 }..][0..16];
176 Ipv6Addr::from(*<&[u8;16]>::try_from(slice).unwrap()).into()
179 _ => throw!(PE::Truncated{ vsn, len: packet.len() }),
183 #[derive(Copy,Clone,Eq,PartialEq,Ord,PartialOrd,Hash)]
184 pub struct DumpHex<'b>(pub &'b [u8]);
185 impl Debug for DumpHex<'_> {
186 #[throws(fmt::Error)]
187 fn fmt(&self, f: &mut fmt::Formatter) {
188 for v in self.0 { write!(f, "{:02x}", v)?; }
189 match str::from_utf8(self.0) {
190 Ok(s) => write!(f, "={:?}", s)?,
191 Err(x) => write!(f, "={:?}..",
192 str::from_utf8(&self.0[0..x.valid_up_to()]).unwrap()
199 fn mime_slip_to_mime() {
200 use PacketError as PE;
203 fn chk<M: SlipMime>(i: &[u8], exp_p: &[&[u8]], exp_e: &[PacketError]) {
204 dbg!(M::CONV_TO, DumpHex(i));
205 let mut got_e = vec![];
206 let mut got_p = vec![];
207 check::<_,_,_,M>(MTU, i, &mut got_p, |_|Ok(()), |e| got_e.push(e));
208 assert_eq!( got_p.iter().map(|b| DumpHex(b)).collect_vec(),
209 exp_p.iter().map(|b| DumpHex(b)).collect_vec() );
215 ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
216 &[ &[ b'-', SLIP_ESC_END, SLIP_ESC, b'X' ] ],
220 ( &[ SLIP_END, SLIP_ESC, b'y' ], &[],
221 &[ PE::Empty, PE::SLIP ]);
224 ( &[ SLIP_END, b'-', b'y' ],
225 &[ &[ SLIP_ESC, b'y' ] ],
231 &[ PE::MTU { len: 20, mtu: MTU } ]);
234 ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
235 &[ &[ SLIP_ESC, SLIP_ESC_END, b'-', b'X' ] ],