feat(client): add proxy::SocksV4 and proxy::SocksV5 connectors (#187)

Adds SocksV4 and SocksV5 connectors with simple configuration for local and remote DNS. Supports SOCKSv5 user/pass authentication and allows optimistic message sending (not in RFC but supported by most servers) to reduce number of round-trips in SOCKSv5 handshake.

cc hyperium/hyper#3851,  #173

Closes hyperium/hyper#3877

Author: JPDye

src/client/legacy/connect/proxy/mod.rs

@@ -1,5 +1,6 @@
 //! Proxy helpers
-
+mod socks;
 mod tunnel;
 
+pub use self::socks::{SocksV4, SocksV5};
 pub use self::tunnel::Tunnel;

src/client/legacy/connect/proxy/socks/mod.rs

@@ -0,0 +1,121 @@
+mod v5;
+pub use v5::{SocksV5, SocksV5Error};
+
+mod v4;
+pub use v4::{SocksV4, SocksV4Error};
+
+use bytes::BytesMut;
+
+use hyper::rt::Read;
+
+#[derive(Debug)]
+pub enum SocksError<C> {
+    Inner(C),
+    Io(std::io::Error),
+
+    DnsFailure,
+    MissingHost,
+    MissingPort,
+
+    V4(SocksV4Error),
+    V5(SocksV5Error),
+
+    Parsing(ParsingError),
+    Serialize(SerializeError),
+}
+
+#[derive(Debug)]
+pub enum ParsingError {
+    Incomplete,
+    WouldOverflow,
+    Other,
+}
+
+#[derive(Debug)]
+pub enum SerializeError {
+    WouldOverflow,
+}
+
+async fn read_message<T, M, C>(mut conn: &mut T, buf: &mut BytesMut) -> Result<M, SocksError<C>>
+where
+    T: Read + Unpin,
+    M: for<'a> TryFrom<&'a mut BytesMut, Error = ParsingError>,
+{
+    let mut tmp = [0; 513];
+
+    loop {
+        let n = crate::rt::read(&mut conn, &mut tmp).await?;
+        buf.extend_from_slice(&tmp[..n]);
+
+        match M::try_from(buf) {
+            Err(ParsingError::Incomplete) => {
+                if n == 0 {
+                    if buf.spare_capacity_mut().len() == 0 {
+                        return Err(SocksError::Parsing(ParsingError::WouldOverflow));
+                    } else {
+                        return Err(std::io::Error::new(
+                            std::io::ErrorKind::UnexpectedEof,
+                            "unexpected eof",
+                        )
+                        .into());
+                    }
+                }
+            }
+            Err(err) => return Err(err.into()),
+            Ok(res) => return Ok(res),
+        }
+    }
+}
+
+impl<C> std::fmt::Display for SocksError<C> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("SOCKS error: ")?;
+
+        match self {
+            Self::Inner(_) => f.write_str("failed to create underlying connection"),
+            Self::Io(_) => f.write_str("io error during SOCKS handshake"),
+
+            Self::DnsFailure => f.write_str("could not resolve to acceptable address type"),
+            Self::MissingHost => f.write_str("missing destination host"),
+            Self::MissingPort => f.write_str("missing destination port"),
+
+            Self::Parsing(_) => f.write_str("failed parsing server response"),
+            Self::Serialize(_) => f.write_str("failed serialize request"),
+
+            Self::V4(e) => e.fmt(f),
+            Self::V5(e) => e.fmt(f),
+        }
+    }
+}
+
+impl<C: std::fmt::Debug + std::fmt::Display> std::error::Error for SocksError<C> {}
+
+impl<C> From<std::io::Error> for SocksError<C> {
+    fn from(err: std::io::Error) -> Self {
+        Self::Io(err)
+    }
+}
+
+impl<C> From<ParsingError> for SocksError<C> {
+    fn from(err: ParsingError) -> Self {
+        Self::Parsing(err)
+    }
+}
+
+impl<C> From<SerializeError> for SocksError<C> {
+    fn from(err: SerializeError) -> Self {
+        Self::Serialize(err)
+    }
+}
+
+impl<C> From<SocksV4Error> for SocksError<C> {
+    fn from(err: SocksV4Error) -> Self {
+        Self::V4(err)
+    }
+}
+
+impl<C> From<SocksV5Error> for SocksError<C> {
+    fn from(err: SocksV5Error) -> Self {
+        Self::V5(err)
+    }
+}

src/client/legacy/connect/proxy/socks/v4/errors.rs

@@ -0,0 +1,22 @@
+use super::Status;
+
+#[derive(Debug)]
+pub enum SocksV4Error {
+    IpV6,
+    Command(Status),
+}
+
+impl From<Status> for SocksV4Error {
+    fn from(err: Status) -> Self {
+        Self::Command(err)
+    }
+}
+
+impl std::fmt::Display for SocksV4Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::IpV6 => f.write_str("IPV6 is not supported"),
+            Self::Command(status) => status.fmt(f),
+        }
+    }
+}

src/client/legacy/connect/proxy/socks/v4/messages.rs

@@ -0,0 +1,131 @@
+use super::super::{ParsingError, SerializeError};
+
+use bytes::{Buf, BufMut, BytesMut};
+use std::net::SocketAddrV4;
+
+/// +-----+-----+----+----+----+----+----+----+-------------+------+------------+------+
+/// |  VN |  CD | DSTPORT |        DSTIP      |    USERID   | NULL |   DOMAIN   | NULL |
+/// +-----+-----+----+----+----+----+----+----+-------------+------+------------+------+
+/// |  1  |  1  |    2    |         4         |   Variable  |  1   |  Variable  |   1  |
+/// +-----+-----+----+----+----+----+----+----+-------------+------+------------+------+
+///                                                                ^^^^^^^^^^^^^^^^^^^^^
+///                                                      optional: only do IP is 0.0.0.X
+#[derive(Debug)]
+pub struct Request<'a>(pub &'a Address);
+
+/// +-----+-----+----+----+----+----+----+----+
+/// |  VN |  CD | DSTPORT |       DSTIP       |
+/// +-----+-----+----+----+----+----+----+----+
+/// |  1  |  1  |    2    |         4         |
+/// +-----+-----+----+----+----+----+----+----+
+///             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+///              ignore: only for SOCKSv4 BIND
+#[derive(Debug)]
+pub struct Response(pub Status);
+
+#[derive(Debug)]
+pub enum Address {
+    Socket(SocketAddrV4),
+    Domain(String, u16),
+}
+
+#[derive(Debug, PartialEq)]
+pub enum Status {
+    Success = 90,
+    Failed = 91,
+    IdentFailure = 92,
+    IdentMismatch = 93,
+}
+
+impl Request<'_> {
+    pub fn write_to_buf<B: BufMut>(&self, mut buf: B) -> Result<usize, SerializeError> {
+        match self.0 {
+            Address::Socket(socket) => {
+                if buf.remaining_mut() < 10 {
+                    return Err(SerializeError::WouldOverflow);
+                }
+
+                buf.put_u8(0x04); // Version
+                buf.put_u8(0x01); // CONNECT
+
+                buf.put_u16(socket.port()); // Port
+                buf.put_slice(&socket.ip().octets()); // IP
+
+                buf.put_u8(0x00); // USERID
+                buf.put_u8(0x00); // NULL
+
+                Ok(10)
+            }
+
+            Address::Domain(domain, port) => {
+                if buf.remaining_mut() < 10 + domain.len() + 1 {
+                    return Err(SerializeError::WouldOverflow);
+                }
+
+                buf.put_u8(0x04); // Version
+                buf.put_u8(0x01); // CONNECT
+
+                buf.put_u16(*port); // IP
+                buf.put_slice(&[0x00, 0x00, 0x00, 0xFF]); // Invalid IP
+
+                buf.put_u8(0x00); // USERID
+                buf.put_u8(0x00); // NULL
+
+                buf.put_slice(domain.as_bytes()); // Domain
+                buf.put_u8(0x00); // NULL
+
+                Ok(10 + domain.len() + 1)
+            }
+        }
+    }
+}
+
+impl TryFrom<&mut BytesMut> for Response {
+    type Error = ParsingError;
+
+    fn try_from(buf: &mut BytesMut) -> Result<Self, Self::Error> {
+        if buf.remaining() < 8 {
+            return Err(ParsingError::Incomplete);
+        }
+
+        if buf.get_u8() != 0x00 {
+            return Err(ParsingError::Other);
+        }
+
+        let status = buf.get_u8().try_into()?;
+        let _addr = {
+            let port = buf.get_u16();
+            let mut ip = [0; 4];
+            buf.copy_to_slice(&mut ip);
+
+            SocketAddrV4::new(ip.into(), port)
+        };
+
+        return Ok(Self(status));
+    }
+}
+
+impl TryFrom<u8> for Status {
+    type Error = ParsingError;
+
+    fn try_from(byte: u8) -> Result<Self, Self::Error> {
+        Ok(match byte {
+            90 => Self::Success,
+            91 => Self::Failed,
+            92 => Self::IdentFailure,
+            93 => Self::IdentMismatch,
+            _ => return Err(ParsingError::Other),
+        })
+    }
+}
+
+impl std::fmt::Display for Status {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            Self::Success => "success",
+            Self::Failed => "server failed to execute command",
+            Self::IdentFailure => "server ident service failed",
+            Self::IdentMismatch => "server ident service did not recognise client identifier",
+        })
+    }
+}