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("bad, IPv{vsn}, len={len}")] Bad { 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; }
27 pub fn check<AC, EH, OUT, M: SlipMime>(
33 ) where OUT: Extend<Box<[u8]>>,
34 AC: Fn(&[u8]) -> Result<(), PacketError> + Copy,
35 EH: FnMut(PacketError),
37 // eprintln!("before: {:?}", DumpHex(data));
38 for packet in data.split(|&c| c == SLIP_END) {
39 match check1::<AC,M>(mtu, packet, addr_chk) {
40 Err(e) => error_handler(e),
41 Ok(packet) => out.extend(iter::once(packet)),
44 // eprintln!(" after: {:?}", DumpHex(data));
47 #[throws(PacketError)]
48 pub fn check1<AC, M: SlipMime>(
53 where AC: Fn(&[u8]) -> Result<(), PacketError>,
55 if packet.len() == 0 {
56 throw!(PacketError::Empty)
58 if packet.len() > mtu.sat() {
59 throw!(PacketError::MTU { len: packet.len(), mtu });
62 let mut packet: Box<[u8]> = packet.to_owned().into();
63 let mut walk: &mut [u8] = &mut packet;
64 let mut header = [0u8; HEADER_FOR_ADDR];
65 let mut wheader = &mut header[..];
67 while let Some((i, was_mime)) = walk.iter().enumerate().find_map(
69 SLIP_ESC => Some((i,false)),
70 SLIP_MIME_ESC if M::CONV_TO.is_some() => Some((i,true)),
74 let _ = wheader.write(&walk[0..i]);
75 if M::CONV_TO.is_some() {
76 walk[i] = if was_mime { SLIP_ESC } else { SLIP_MIME_ESC };
78 if Some(was_mime) != M::CONV_TO {
79 let c = match walk.get(i+1) {
80 Some(&SLIP_ESC_ESC) => SLIP_ESC,
81 Some(&SLIP_ESC_END) => SLIP_END,
82 _ => throw!(PacketError::SLIP),
84 let _ = wheader.write(&[c]);
85 walk = &mut walk[i+2 ..];
87 let _ = wheader.write(&[SLIP_MIME_ESC]);
88 walk = &mut walk[i+1 ..];
91 let _ = wheader.write(walk);
98 pub type Frame = Vec<u8>;
99 pub type FramesData = Vec<Vec<u8>>;
100 //pub type Frame = Box<[u8]>;
101 //pub type FramesData = Vec<Frame>;
102 // `From<Box<[u8]>>` is not implemented for `Bytes`
112 impl Debug for Frames {
113 #[throws(fmt::Error)]
114 fn fmt(&self, f: &mut fmt::Formatter) {
115 write!(f, "Frames{{n={},len={}}}", &self.frames.len(), &self.total_len)?;
121 pub fn add(&mut self, max: u32, frame: Frame) {
122 if frame.len() == 0 { return }
123 let new_total = self.total_len + frame.len() + 1;
124 if new_total > max.sat() { self.tried_full = true; throw!(frame); }
125 self.total_len = new_total;
126 self.frames.push(frame);
129 #[inline] pub fn tried_full(&self) -> bool { self.tried_full }
130 #[inline] pub fn is_empty(&self) -> bool { self.frames.is_empty() }
133 impl From<Frames> for FramesData {
134 fn from(frames: Frames) -> FramesData { frames.frames }
137 const HEADER_FOR_ADDR: usize = 40;
139 #[throws(PacketError)]
140 pub fn ip_packet_addr<const DST: bool>(packet: &[u8]) -> IpAddr {
141 let vsn = (packet.get(0).ok_or_else(|| PE::Empty)? & 0xf0) >> 4;
143 4 if packet.len() >= 20 => {
144 let slice = &packet[if DST { 16 } else { 12 }..][0..4];
145 Ipv4Addr::from(*<&[u8;4]>::try_from(slice).unwrap()).into()
148 6 if packet.len() >= 40 => {
149 let slice = &packet[if DST { 24 } else { 8 }..][0..16];
150 Ipv6Addr::from(*<&[u8;16]>::try_from(slice).unwrap()).into()
153 _ => throw!(PE::Bad{ vsn, len: packet.len() }),
157 #[derive(Copy,Clone,Eq,PartialEq,Ord,PartialOrd,Hash)]
158 pub struct DumpHex<'b>(pub &'b [u8]);
159 impl Debug for DumpHex<'_> {
160 #[throws(fmt::Error)]
161 fn fmt(&self, f: &mut fmt::Formatter) {
162 for v in self.0 { write!(f, "{:02x}", v)?; }
167 fn mime_slip_to_mime() {
168 use PacketError as PE;
171 fn chk<M: SlipMime>(i: &[u8], exp_p: &[&[u8]], exp_e: &[PacketError]) {
172 dbg!(M::CONV_TO, DumpHex(i));
173 let mut got_e = vec![];
174 let mut got_p = vec![];
175 check::<_,_,_,M>(MTU, i, &mut got_p, |_|Ok(()), |e| got_e.push(e));
176 assert_eq!( got_p.iter().map(|b| DumpHex(b)).collect_vec(),
177 exp_p.iter().map(|b| DumpHex(b)).collect_vec() );
183 ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
184 &[ &[ b'-', SLIP_ESC_END, SLIP_ESC, b'X' ] ],
188 ( &[ SLIP_END, SLIP_ESC, b'y' ], &[],
189 &[ PE::Empty, PE::SLIP ]);
192 ( &[ SLIP_END, b'-', b'y' ],
193 &[ &[ SLIP_ESC, b'y' ] ],
199 &[ PE::MTU { len: 20, mtu: MTU } ]);
202 ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
203 &[ &[ SLIP_ESC, SLIP_ESC_END, b'-', b'X' ] ],