libp2p_dcutr/protocol/
inbound.rs

1// Copyright 2021 Protocol Labs.
2//
3// Permission is hereby granted, free of charge, to any person obtaining a
4// copy of this software and associated documentation files (the "Software"),
5// to deal in the Software without restriction, including without limitation
6// the rights to use, copy, modify, merge, publish, distribute, sublicense,
7// and/or sell copies of the Software, and to permit persons to whom the
8// Software is furnished to do so, subject to the following conditions:
9//
10// The above copyright notice and this permission notice shall be included in
11// all copies or substantial portions of the Software.
12//
13// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
14// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
18// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
19// DEALINGS IN THE SOFTWARE.
20
21use std::io;
22
23use asynchronous_codec::Framed;
24use futures::prelude::*;
25use libp2p_core::{multiaddr::Protocol, Multiaddr};
26use libp2p_swarm::Stream;
27use thiserror::Error;
28
29use crate::proto;
30
31pub(crate) async fn handshake(
32    stream: Stream,
33    candidates: Vec<Multiaddr>,
34) -> Result<Vec<Multiaddr>, Error> {
35    let mut stream = Framed::new(
36        stream,
37        quick_protobuf_codec::Codec::new(super::MAX_MESSAGE_SIZE_BYTES),
38    );
39
40    let proto::HolePunch { type_pb, ObsAddrs } = stream
41        .next()
42        .await
43        .ok_or(io::Error::from(io::ErrorKind::UnexpectedEof))??;
44
45    if ObsAddrs.is_empty() {
46        return Err(Error::Protocol(ProtocolViolation::NoAddresses));
47    };
48
49    let obs_addrs = ObsAddrs
50        .into_iter()
51        .filter_map(|a| match Multiaddr::try_from(a.to_vec()) {
52            Ok(a) => Some(a),
53            Err(e) => {
54                tracing::debug!("Unable to parse multiaddr: {e}");
55                None
56            }
57        })
58        // Filter out relayed addresses.
59        .filter(|a| {
60            if a.iter().any(|p| p == Protocol::P2pCircuit) {
61                tracing::debug!(address=%a, "Dropping relayed address");
62                false
63            } else {
64                true
65            }
66        })
67        .collect();
68
69    if !matches!(type_pb, proto::Type::CONNECT) {
70        return Err(Error::Protocol(ProtocolViolation::UnexpectedTypeSync));
71    }
72
73    let msg = proto::HolePunch {
74        type_pb: proto::Type::CONNECT,
75        ObsAddrs: candidates.into_iter().map(|a| a.to_vec()).collect(),
76    };
77
78    stream.send(msg).await?;
79    let proto::HolePunch { type_pb, .. } = stream
80        .next()
81        .await
82        .ok_or(io::Error::from(io::ErrorKind::UnexpectedEof))??;
83
84    if !matches!(type_pb, proto::Type::SYNC) {
85        return Err(Error::Protocol(ProtocolViolation::UnexpectedTypeConnect));
86    }
87
88    Ok(obs_addrs)
89}
90
91#[derive(Debug, Error)]
92pub enum Error {
93    #[error("IO error")]
94    Io(#[from] io::Error),
95    #[error("Protocol error")]
96    Protocol(#[from] ProtocolViolation),
97}
98
99impl From<quick_protobuf_codec::Error> for Error {
100    fn from(e: quick_protobuf_codec::Error) -> Self {
101        Error::Protocol(ProtocolViolation::Codec(e))
102    }
103}
104
105#[derive(Debug, Error)]
106pub enum ProtocolViolation {
107    #[error(transparent)]
108    Codec(#[from] quick_protobuf_codec::Error),
109    #[error("Expected at least one address in reservation.")]
110    NoAddresses,
111    #[error("Failed to parse response type field.")]
112    ParseTypeField,
113    #[error("Unexpected message type 'connect'")]
114    UnexpectedTypeConnect,
115    #[error("Unexpected message type 'sync'")]
116    UnexpectedTypeSync,
117}
libp2p_dcutr/protocol/inbound.rs

libp2p_dcutr/protocol/
inbound.rs
