1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71

pub mod conn_bridge;
pub mod conn_disconnected_packet;
pub mod conn_pipe;
pub mod conn_udp;
pub mod conn_udp_listener;

#[cfg(test)]
mod conn_bridge_test;
#[cfg(test)]
mod conn_pipe_test;
#[cfg(test)]
mod conn_test;

//TODO: remove this conditional test
#[cfg(not(target_os = "windows"))]
#[cfg(test)]
mod conn_udp_listener_test;

use async_trait::async_trait;
use std::net::SocketAddr;
use std::sync::Arc;
use tokio::net::ToSocketAddrs;

use crate::error::Result;

#[async_trait]
pub trait Conn {
    async fn connect(&self, addr: SocketAddr) -> Result<()>;
    async fn recv(&self, buf: &mut [u8]) -> Result<usize>;
    async fn recv_from(&self, buf: &mut [u8]) -> Result<(usize, SocketAddr)>;
    async fn send(&self, buf: &[u8]) -> Result<usize>;
    async fn send_to(&self, buf: &[u8], target: SocketAddr) -> Result<usize>;
    async fn local_addr(&self) -> Result<SocketAddr>;
    async fn remote_addr(&self) -> Option<SocketAddr>;
    async fn close(&self) -> Result<()>;
}

/// A Listener is a generic network listener for connection-oriented protocols.
/// Multiple connections may invoke methods on a Listener simultaneously.
#[async_trait]
pub trait Listener {
    /// accept waits for and returns the next connection to the listener.
    async fn accept(&self) -> Result<(Arc<dyn Conn + Send + Sync>, SocketAddr)>;

    /// close closes the listener.
    /// Any blocked accept operations will be unblocked and return errors.
    async fn close(&self) -> Result<()>;

    /// addr returns the listener's network address.
    async fn addr(&self) -> Result<SocketAddr>;
}

pub async fn lookup_host<T>(use_ipv4: bool, host: T) -> Result<SocketAddr>
where
    T: ToSocketAddrs,
{
    for remote_addr in tokio::net::lookup_host(host).await? {
        if (use_ipv4 && remote_addr.is_ipv4()) || (!use_ipv4 && remote_addr.is_ipv6()) {
            return Ok(remote_addr);
        }
    }

    Err(std::io::Error::new(
        std::io::ErrorKind::Other,
        format!(
            "No available {} IP address found!",
            if use_ipv4 { "ipv4" } else { "ipv6" },
        ),
    )
    .into())
}