// Copyright 2021 Ian Jackson and contributors to Hippotat
-// SPDX-License-Identifier: AGPL-3.0-or-later
+// SPDX-License-Identifier: GPL-3.0-or-later
// There is NO WARRANTY.
use crate::prelude::*;
pub static SLIP_END_SLICE: &[u8] = &[SLIP_END];
-#[throws(AE)]
-pub fn check_checkmtu_mimeify(_data: &mut [u8], _ic: &InstanceConfig) {
- // xxx
+#[derive(Error,Debug,Copy,Clone,Eq,PartialEq)]
+pub enum PacketError {
+ #[error("empty packet")] Empty,
+ #[error("MTU exceeded ({len} > {mtu})")] MTU { len: usize, mtu: u32 },
+ #[error("Invalid SLIP escape sequence")] SLIP,
+ #[error("unexpected src addr {0:?}")] Src(IpAddr),
+ #[error("unexpected dst addr {0:?}")] Dst(IpAddr),
+ #[error("truncated, IPv{vsn}, len={len}")] Truncated { len: usize, vsn: u8 },
}
+
+pub trait SlipMime { const CONV_TO: Option<bool>; }
+#[derive(Copy,Clone,Debug)] pub struct Slip2Mime;
+#[derive(Copy,Clone,Debug)] pub struct Mime2Slip;
+#[derive(Copy,Clone,Debug)] pub struct SlipNoConv;
+impl SlipMime for Slip2Mime { const CONV_TO: Option<bool> = Some(true); }
+impl SlipMime for Mime2Slip { const CONV_TO: Option<bool> = Some(false); }
+impl SlipMime for SlipNoConv { const CONV_TO: Option<bool> = None; }
+
+#[derive(Debug)]
+#[derive(Error)]
+#[error("only bad IP datagrams")]
+pub struct ErrorOnlyBad;
+
+#[throws(ErrorOnlyBad)]
+pub fn checkn<AC, EH, OUT, ACR, M: SlipMime+Copy>(
+ mime: M,
+ mtu: u32,
+ data: &[u8],
+ addr_chk: AC,
+ mut out: OUT,
+ mut error_handler: EH
+) where AC: Fn(&[u8]) -> Result<ACR, PacketError> + Copy,
+ OUT: FnMut((Box<[u8]>, ACR)) -> Result<(), PacketError>,
+ EH: FnMut(PacketError),
+{
+ // eprintln!("before: {:?}", DumpHex(data));
+ if data.is_empty() { return }
+ let mut ok = false;
+ let mut err = false;
+ for packet in data.split(|&c| c == SLIP_END) {
+ match (||{
+ let checked = check1(mime, mtu, packet, addr_chk);
+ if matches!(checked, Err(PacketError::Empty)) { return Ok::<_,PE>(()) }
+ out(checked?)?;
+ ok = true;
+ Ok::<_,PE>(())
+ })() {
+ Ok(()) => { },
+ Err(e) => { err=true; error_handler(e); },
+ }
+ }
+// eprintln!(" after: {:?}", DumpHex(data));
+ if err && !ok { throw!(ErrorOnlyBad) }
+}
+
+#[throws(PacketError)]
+pub fn check1<AC, M: SlipMime, ACR>(
+ _mime: M,
+ mtu: u32,
+ packet: &[u8],
+ addr_chk: AC,
+) -> (Box<[u8]>, ACR)
+where AC: Fn(&[u8]) -> Result<ACR, PacketError>,
+{
+ if packet.len() == 0 {
+ throw!(PacketError::Empty)
+ }
+
+ let mut packet: Box<[u8]> = packet.to_owned().into();
+ let mut walk: &mut [u8] = &mut packet;
+ let mut header = [0u8; HEADER_FOR_ADDR];
+ let mut wheader = &mut header[..];
+ let mut escapes = 0;
+
+ while let Some((i, was_mime)) = walk.iter().enumerate().find_map(
+ |(i,&c)| match c {
+ SLIP_ESC => Some((i,false)),
+ SLIP_MIME_ESC if M::CONV_TO.is_some() => Some((i,true)),
+ _ => None,
+ }
+ ) {
+ let _ = wheader.write(&walk[0..i]);
+ if M::CONV_TO.is_some() {
+ walk[i] = if was_mime { SLIP_ESC } else { SLIP_MIME_ESC };
+ }
+ if Some(was_mime) != M::CONV_TO {
+ let c = match walk.get(i+1) {
+ Some(&SLIP_ESC_ESC) => SLIP_ESC,
+ Some(&SLIP_ESC_END) => SLIP_END,
+ _ => throw!(PacketError::SLIP),
+ };
+ let _ = wheader.write(&[c]);
+ walk = &mut walk[i+2 ..];
+ escapes += 1;
+ } else {
+ let _ = wheader.write(&[SLIP_MIME_ESC]);
+ walk = &mut walk[i+1 ..];
+ }
+ }
+ let _ = wheader.write(walk);
+ let wheader_len = wheader.len();
+ let header = &header[0.. header.len() - wheader_len];
+
+ let decoded_len = packet.len() - escapes;
+ if decoded_len > mtu.sat() {
+ throw!(PacketError::MTU { len: decoded_len, mtu });
+ }
+
+ let acr = addr_chk(&header)?;
+
+ (packet, acr)
+}
+
+pub type Frame = Vec<u8>;
+pub type FramesData = Vec<Vec<u8>>;
+// todo: https://github.com/tokio-rs/bytes/pull/504
+// pub type Frame = Box<[u8]>;
+// pub type FramesData = Vec<Frame>;
+// `From<Box<[u8]>>` is not implemented for `Bytes`
+// when this is fixed, there are two `into`s in client.rs which
+// become redundant (search for todo:504)
+
+
+#[derive(Default)]
+pub struct Frames {
+ frames: FramesData,
+ total_len: usize,
+ tried_full: bool,
+}
+
+impl Debug for Frames {
+ #[throws(fmt::Error)]
+ fn fmt(&self, f: &mut fmt::Formatter) {
+ write!(f, "Frames{{n={},len={}}}", &self.frames.len(), &self.total_len)?;
+ }
+}
+
+impl Frames {
+ #[throws(Frame)]
+ pub fn add(&mut self, max: u32, frame: Frame) {
+ if frame.len() == 0 { return }
+ let new_total = self.total_len + frame.len() + 1;
+ if new_total > max.sat() { self.tried_full = true; throw!(frame); }
+ self.total_len = new_total;
+ self.frames.push(frame);
+ }
+
+ #[inline] pub fn tried_full(&self) -> bool { self.tried_full }
+ #[inline] pub fn is_empty(&self) -> bool { self.frames.is_empty() }
+}
+
+impl From<Frames> for FramesData {
+ fn from(frames: Frames) -> FramesData { frames.frames }
+}
+
+const HEADER_FOR_ADDR: usize = 40;
+
+#[throws(PacketError)]
+pub fn ip_packet_addr<const DST: bool>(packet: &[u8]) -> IpAddr {
+ let vsn = (packet.get(0).ok_or_else(|| PE::Empty)? & 0xf0) >> 4;
+ match vsn {
+ 4 if packet.len() >= 20 => {
+ let slice = &packet[if DST { 16 } else { 12 }..][0..4];
+ Ipv4Addr::from(*<&[u8;4]>::try_from(slice).unwrap()).into()
+ },
+
+ 6 if packet.len() >= 40 => {
+ let slice = &packet[if DST { 24 } else { 8 }..][0..16];
+ Ipv6Addr::from(*<&[u8;16]>::try_from(slice).unwrap()).into()
+ },
+
+ _ => throw!(PE::Truncated{ vsn, len: packet.len() }),
+ }
+}
+
+#[derive(Copy,Clone,Eq,PartialEq,Ord,PartialOrd,Hash)]
+pub struct DumpHex<'b>(pub &'b [u8]);
+impl Debug for DumpHex<'_> {
+ #[throws(fmt::Error)]
+ fn fmt(&self, f: &mut fmt::Formatter) {
+ for v in self.0 { write!(f, "{:02x}", v)?; }
+ match str::from_utf8(self.0) {
+ Ok(s) => write!(f, "={:?}", s)?,
+ Err(x) => write!(f, "={:?}..",
+ str::from_utf8(&self.0[0..x.valid_up_to()]).unwrap()
+ )?,
+ }
+ }
+}
+
+#[test]
+fn mime_slip_to_mime() {
+ use PacketError as PE;
+ const MTU: u32 = 10;
+
+ fn chk<M: SlipMime>(i: &[u8], exp_p: &[&[u8]], exp_e: &[PacketError]) {
+ dbg!(M::CONV_TO, DumpHex(i));
+ let mut got_e = vec![];
+ let mut got_p = vec![];
+ check::<_,_,_,M>(MTU, i, &mut got_p, |_|Ok(()), |e| got_e.push(e));
+ assert_eq!( got_p.iter().map(|b| DumpHex(b)).collect_vec(),
+ exp_p.iter().map(|b| DumpHex(b)).collect_vec() );
+ assert_eq!( got_e,
+ exp_e );
+ }
+
+ chk::<Slip2Mime>
+ ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
+ &[ &[ b'-', SLIP_ESC_END, SLIP_ESC, b'X' ] ],
+ &[ PE::Empty ]);
+
+ chk::<Slip2Mime>
+ ( &[ SLIP_END, SLIP_ESC, b'y' ], &[],
+ &[ PE::Empty, PE::SLIP ]);
+
+ chk::<Slip2Mime>
+ ( &[ SLIP_END, b'-', b'y' ],
+ &[ &[ SLIP_ESC, b'y' ] ],
+ &[ PE::Empty ]);
+
+ chk::<Slip2Mime>
+ ( &[b'x'; 20],
+ &[ ],
+ &[ PE::MTU { len: 20, mtu: MTU } ]);
+
+ chk::<SlipNoConv>
+ ( &[ SLIP_END, SLIP_ESC, SLIP_ESC_END, b'-', b'X' ],
+ &[ &[ SLIP_ESC, SLIP_ESC_END, b'-', b'X' ] ],
+ &[ PE::Empty, ]);
+}
+
+
~ian / hippotat.git / blobdiff