Add Upstream trait (WIP)

src/relay/dnsrelay/mod.rs

@@ -31,6 +31,8 @@ use crate::{
     },
 };
 
+pub mod upstream;
+
 async fn udp_lookup(qname: &Name, qtype: RecordType, server: &SocketAddr) -> io::Result<Message> {
     let bind_addr = SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(0, 0, 0, 0), 0));
     let mut socket = UdpSocket::bind(bind_addr).await?;

src/relay/dnsrelay/upstream.rs

@@ -0,0 +1,59 @@
+use std::io::Result;
+use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, UdpSocket};
+use trust_dns_proto::op::Message;
+
+pub trait Upstream {
+    async fn lookup(&self, request: &Message) -> Result<Message>;
+}
+
+struct UdpUpstream {
+    server: SocketAddr,
+}
+
+impl Upstream for UdpUpstream {
+    async fn lookup(&self, request: &Message) -> Result<Message> {
+        let socket = UdpSocket::bind(SocketAddr::new(match *self.server {
+            SocketAddr::V4(..) => IpAddr::v4(Ipv4Addr::new(0, 0, 0, 0)),
+            SocketAddr::V6(..) => IpAddr::v6(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 0)),
+        }, 0)).await?;
+        socket.send_to(&request.to_vec()?, self.server).await?;
+        let mut response = vec![0; 512];
+        socket.recv_from(&mut response).await?;
+        Ok(Message::from_vec(&response)?)
+    }
+}
+
+struct Socks5UdpUpstream {
+    server: SocketAddr,
+}
+
+impl Upstream for Socks5UdpUpstream {
+    async fn lookup(&self, request: &Message) -> Result<Message> {
+        let socket = UdpSocket::bind(SocketAddr::new(IpAddr::v4(Ipv4Addr::new(0, 0, 0, 0)), 0)).await?;
+        unimplemented!()
+    }
+}
+
+struct TcpUpstream {
+    server: SocketAddr,
+}
+
+impl Upstream for TcpUpstream {
+    async fn lookup(&self, request: &Message) -> Result<Message> {
+        unimplemented!()
+    }
+}
+
+#[cfg(any(target_os = "linux", target_os = "android"))]
+struct UnixSocketUpstream {
+    path: String,
+}
+
+#[cfg(any(target_os = "linux", target_os = "android"))]
+impl Upstream for UnixSocketUpstream {
+    async fn lookup(&self, request: &Message) -> Result<Message> {
+        use tokio::net::UnixStream;
+        let socket = UnixStream::connect(path).await?;
+        unimplemented!()
+    }
+}