Aleksandr BogomiakovandClaude
9966b50407
The command line package is now `tsunagi` and builds the `tsng` executable, which the packages, the unit, the installers and the workflows install and run. The core library package becomes `tsunagi-core`, keeping the library name `tsunagi`, so no code changes `use tsunagi::...`. Directories follow (crates/tsunagi-core, crates/tsunagi). Every command shown to a person is now `tsng ...`. Co-Authored-By: Claude <noreply@anthropic.com>
85 lines
2.6 KiB
Rust
85 lines
2.6 KiB
Rust
//! Fixed header. Transit changes one byte in an owned receive buffer.
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use super::{FlowId, PeerId};
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use crate::config::{MAX_DATA_DATAGRAM, ROUTING_HOP_LIMIT};
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use bytes::{BufMut, Bytes, BytesMut};
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pub(crate) const HEADER: usize = 2 + 32 + 32 + 8;
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const VERSION: u8 = 1;
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#[derive(Debug, PartialEq, Eq)]
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pub(crate) struct Header {
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pub source: PeerId,
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pub destination: PeerId,
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pub remaining: u8,
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pub flow: FlowId,
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}
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pub(crate) fn decode(bytes: &[u8]) -> Option<Header> {
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if bytes.len() < HEADER
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|| bytes.len() > MAX_DATA_DATAGRAM
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|| bytes[0] != VERSION
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|| bytes[1] == 0
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|| bytes[1] > ROUTING_HOP_LIMIT
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{
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return None;
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}
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Some(Header {
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source: bytes[2..34].try_into().ok()?,
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destination: bytes[34..66].try_into().ok()?,
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remaining: bytes[1],
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flow: u64::from_be_bytes(bytes[66..74].try_into().ok()?),
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})
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}
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pub(crate) fn encode(source: PeerId, destination: PeerId, flow: FlowId, payload: &[u8]) -> Bytes {
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let mut bytes = BytesMut::with_capacity(HEADER + payload.len());
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bytes.put_u8(VERSION);
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bytes.put_u8(ROUTING_HOP_LIMIT);
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bytes.extend_from_slice(&source);
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bytes.extend_from_slice(&destination);
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bytes.put_u64(flow);
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bytes.extend_from_slice(payload);
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bytes.freeze()
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}
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pub(crate) fn decrement(bytes: Bytes) -> Bytes {
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let mut bytes = match bytes.try_into_mut() {
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Ok(bytes) => bytes,
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Err(bytes) => BytesMut::from(bytes.as_ref()),
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};
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// Called only after decode and after excluding remaining <= 1.
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bytes[1] -= 1;
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bytes.freeze()
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}
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#[cfg(test)]
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mod tests {
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#![allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
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use super::*;
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#[test]
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fn transit_reuses_the_buffer_and_rejects_invalid_headers() {
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let frame = encode([1; 32], [2; 32], 17, &[42; 1280]);
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let address = frame.as_ptr();
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let frame = decrement(frame);
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assert_eq!(
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frame.as_ptr(),
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address,
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"no payload copy for an owned buffer"
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);
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assert_eq!(decode(&frame).unwrap().remaining, ROUTING_HOP_LIMIT - 1);
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assert_eq!(&frame[HEADER..], &[42; 1280]);
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for length in 0..HEADER {
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assert!(decode(&frame[..length]).is_none());
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}
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for ttl in [0, ROUTING_HOP_LIMIT + 1] {
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let mut bad = frame.to_vec();
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bad[1] = ttl;
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assert!(decode(&bad).is_none());
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}
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let mut bad = frame.to_vec();
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bad[0] = 99;
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assert!(decode(&bad).is_none());
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assert!(decode(&vec![1; MAX_DATA_DATAGRAM + 1]).is_none());
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}
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}
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