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: FnMut(&[u8]) -> Result<(), PacketError>,
35 EH: FnMut(PacketError),
37 // eprintln!("before: {:?}", DumpHex(data));
38 for packet in data.split(|&c| c == SLIP_END) {
40 if packet.len() == 0 {
41 throw!(PacketError::Empty)
43 if packet.len() > mtu.sat() {
44 throw!(PacketError::MTU { len: packet.len(), mtu });
47 let mut packet: Box<[u8]> = packet.to_owned().into();
48 let mut walk: &mut [u8] = &mut packet;
49 let mut header = [0u8; HEADER_FOR_ADDR];
50 let mut wheader = &mut header[..];
52 while let Some((i, was_mime)) = walk.iter().enumerate().find_map(
54 SLIP_ESC => Some((i,false)),
55 SLIP_MIME_ESC if M::CONV_TO.is_some() => Some((i,true)),
59 let _ = wheader.write(&walk[0..i]);
60 if M::CONV_TO.is_some() {
61 walk[i] = if was_mime { SLIP_ESC } else { SLIP_MIME_ESC };
63 if Some(was_mime) != M::CONV_TO {
64 let c = match walk.get(i+1) {
65 Some(&SLIP_ESC_ESC) => SLIP_ESC,
66 Some(&SLIP_ESC_END) => SLIP_END,
67 _ => throw!(PacketError::SLIP),
69 let _ = wheader.write(&[c]);
70 walk = &mut walk[i+2 ..];
72 let _ = wheader.write(&[SLIP_MIME_ESC]);
73 walk = &mut walk[i+1 ..];
76 let _ = wheader.write(walk);
82 Err(e) => error_handler(e),
83 Ok(packet) => out.extend(iter::once(packet)),
86 // eprintln!(" after: {:?}", DumpHex(data));
89 pub type Frame = Vec<u8>;
90 pub type FramesData = Vec<Vec<u8>>;
91 //pub type Frame = Box<[u8]>;
92 //pub type FramesData = Vec<Frame>;
93 // `From<Box<[u8]>>` is not implemented for `Bytes`
103 impl Debug for Frames {
104 #[throws(fmt::Error)]
105 fn fmt(&self, f: &mut fmt::Formatter) {
106 write!(f, "Frames{{n={},len={}}}", &self.frames.len(), &self.total_len)?;
112 pub fn add(&mut self, max: u32, frame: Frame) {
113 if frame.len() == 0 { return }
114 let new_total = self.total_len + frame.len() + 1;
115 if new_total > max.sat() { self.tried_full = true; throw!(frame); }
116 self.total_len = new_total;
117 self.frames.push(frame);
120 #[inline] pub fn tried_full(&self) -> bool { self.tried_full }
121 #[inline] pub fn is_empty(&self) -> bool { self.frames.is_empty() }
124 impl From<Frames> for FramesData {
125 fn from(frames: Frames) -> FramesData { frames.frames }
128 const HEADER_FOR_ADDR: usize = 40;
130 #[throws(PacketError)]
131 pub fn ip_packet_addr<const DST: bool>(packet: &[u8]) -> IpAddr {
132 let vsn = (packet.get(0).ok_or_else(|| PE::Empty)? & 0xf0) >> 4;
134 4 if packet.len() >= 20 => {
135 let slice = &packet[if DST { 16 } else { 12 }..][0..4];
136 Ipv4Addr::from(*<&[u8;4]>::try_from(slice).unwrap()).into()
139 6 if packet.len() >= 40 => {
140 let slice = &packet[if DST { 24 } else { 8 }..][0..16];
141 Ipv6Addr::from(*<&[u8;16]>::try_from(slice).unwrap()).into()
144 _ => throw!(PE::Bad{ vsn, len: packet.len() }),
148 #[derive(Copy,Clone,Eq,PartialEq,Ord,PartialOrd,Hash)]
149 pub struct DumpHex<'b>(pub &'b [u8]);
150 impl Debug for DumpHex<'_> {
151 #[throws(fmt::Error)]
152 fn fmt(&self, f: &mut fmt::Formatter) {
153 for v in self.0 { write!(f, "{:02x}", v)?; }
158 fn mime_slip_to_mime() {
159 use PacketError as PE;
162 fn chk<M: SlipMime>(i: &[u8], exp_p: &[&[u8]], exp_e: &[PacketError]) {
163 dbg!(M::CONV_TO, DumpHex(i));
164 let mut got_e = vec![];
165 let mut got_p = vec![];
166 check::<_,_,_,M>(MTU, i, &mut got_p, |_|Ok(()), |e| got_e.push(e));
167 assert_eq!( got_p.iter().map(|b| DumpHex(b)).collect_vec(),
168 exp_p.iter().map(|b| DumpHex(b)).collect_vec() );
174 ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
175 &[ &[ b'-', SLIP_ESC_END, SLIP_ESC, b'X' ] ],
179 ( &[ SLIP_END, SLIP_ESC, b'y' ], &[],
180 &[ PE::Empty, PE::SLIP ]);
183 ( &[ SLIP_END, b'-', b'y' ],
184 &[ &[ SLIP_ESC, b'y' ] ],
190 &[ PE::MTU { len: 20, mtu: MTU } ]);
193 ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
194 &[ &[ SLIP_ESC, SLIP_ESC_END, b'-', b'X' ] ],