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 OUT: Extend<Box<[u8]>>,
39 AC: Fn(&[u8]) -> Result<(), PacketError> + Copy,
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) {
47 match check1(mime, mtu, packet, addr_chk) {
48 Err(PacketError::Empty) => { }
49 Err(e) => { err=true; error_handler(e); },
50 Ok(packet) => { ok=true; out.extend(iter::once(packet)); },
53 // eprintln!(" after: {:?}", DumpHex(data));
54 if err && !ok { throw!(ErrorOnlyBad) }
57 #[throws(PacketError)]
58 pub fn check1<AC, M: SlipMime>(
64 where AC: Fn(&[u8]) -> Result<(), PacketError>,
66 if packet.len() == 0 {
67 throw!(PacketError::Empty)
70 let mut packet: Box<[u8]> = packet.to_owned().into();
71 let mut walk: &mut [u8] = &mut packet;
72 let mut header = [0u8; HEADER_FOR_ADDR];
73 let mut wheader = &mut header[..];
76 while let Some((i, was_mime)) = walk.iter().enumerate().find_map(
78 SLIP_ESC => Some((i,false)),
79 SLIP_MIME_ESC if M::CONV_TO.is_some() => Some((i,true)),
83 let _ = wheader.write(&walk[0..i]);
84 if M::CONV_TO.is_some() {
85 walk[i] = if was_mime { SLIP_ESC } else { SLIP_MIME_ESC };
87 if Some(was_mime) != M::CONV_TO {
88 let c = match walk.get(i+1) {
89 Some(&SLIP_ESC_ESC) => SLIP_ESC,
90 Some(&SLIP_ESC_END) => SLIP_END,
91 _ => throw!(PacketError::SLIP),
93 let _ = wheader.write(&[c]);
94 walk = &mut walk[i+2 ..];
97 let _ = wheader.write(&[SLIP_MIME_ESC]);
98 walk = &mut walk[i+1 ..];
101 let _ = wheader.write(walk);
102 let wheader_len = wheader.len();
103 let header = &header[0.. header.len() - wheader_len];
105 let decoded_len = packet.len() - escapes;
106 if decoded_len > mtu.sat() {
107 throw!(PacketError::MTU { len: decoded_len, mtu });
115 pub type Frame = Vec<u8>;
116 pub type FramesData = Vec<Vec<u8>>;
117 // todo: https://github.com/tokio-rs/bytes/pull/504
118 // pub type Frame = Box<[u8]>;
119 // pub type FramesData = Vec<Frame>;
120 // `From<Box<[u8]>>` is not implemented for `Bytes`
121 // when this is fixed, there are two `into`s in client.rs which
122 // become redundant (search for todo:504)
132 impl Debug for Frames {
133 #[throws(fmt::Error)]
134 fn fmt(&self, f: &mut fmt::Formatter) {
135 write!(f, "Frames{{n={},len={}}}", &self.frames.len(), &self.total_len)?;
141 pub fn add(&mut self, max: u32, frame: Frame) {
142 if frame.len() == 0 { return }
143 let new_total = self.total_len + frame.len() + 1;
144 if new_total > max.sat() { self.tried_full = true; throw!(frame); }
145 self.total_len = new_total;
146 self.frames.push(frame);
149 #[inline] pub fn tried_full(&self) -> bool { self.tried_full }
150 #[inline] pub fn is_empty(&self) -> bool { self.frames.is_empty() }
153 impl From<Frames> for FramesData {
154 fn from(frames: Frames) -> FramesData { frames.frames }
157 const HEADER_FOR_ADDR: usize = 40;
159 #[throws(PacketError)]
160 pub fn ip_packet_addr<const DST: bool>(packet: &[u8]) -> IpAddr {
161 let vsn = (packet.get(0).ok_or_else(|| PE::Empty)? & 0xf0) >> 4;
163 4 if packet.len() >= 20 => {
164 let slice = &packet[if DST { 16 } else { 12 }..][0..4];
165 Ipv4Addr::from(*<&[u8;4]>::try_from(slice).unwrap()).into()
168 6 if packet.len() >= 40 => {
169 let slice = &packet[if DST { 24 } else { 8 }..][0..16];
170 Ipv6Addr::from(*<&[u8;16]>::try_from(slice).unwrap()).into()
173 _ => throw!(PE::Truncated{ vsn, len: packet.len() }),
177 #[derive(Copy,Clone,Eq,PartialEq,Ord,PartialOrd,Hash)]
178 pub struct DumpHex<'b>(pub &'b [u8]);
179 impl Debug for DumpHex<'_> {
180 #[throws(fmt::Error)]
181 fn fmt(&self, f: &mut fmt::Formatter) {
182 for v in self.0 { write!(f, "{:02x}", v)?; }
183 match str::from_utf8(self.0) {
184 Ok(s) => write!(f, "={:?}", s)?,
185 Err(x) => write!(f, "={:?}..",
186 str::from_utf8(&self.0[0..x.valid_up_to()]).unwrap()
193 fn mime_slip_to_mime() {
194 use PacketError as PE;
197 fn chk<M: SlipMime>(i: &[u8], exp_p: &[&[u8]], exp_e: &[PacketError]) {
198 dbg!(M::CONV_TO, DumpHex(i));
199 let mut got_e = vec![];
200 let mut got_p = vec![];
201 check::<_,_,_,M>(MTU, i, &mut got_p, |_|Ok(()), |e| got_e.push(e));
202 assert_eq!( got_p.iter().map(|b| DumpHex(b)).collect_vec(),
203 exp_p.iter().map(|b| DumpHex(b)).collect_vec() );
209 ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
210 &[ &[ b'-', SLIP_ESC_END, SLIP_ESC, b'X' ] ],
214 ( &[ SLIP_END, SLIP_ESC, b'y' ], &[],
215 &[ PE::Empty, PE::SLIP ]);
218 ( &[ SLIP_END, b'-', b'y' ],
219 &[ &[ SLIP_ESC, b'y' ] ],
225 &[ PE::MTU { len: 20, mtu: MTU } ]);
228 ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
229 &[ &[ SLIP_ESC, SLIP_ESC_END, b'-', b'X' ] ],