Struct Connect

pub struct Connect<S> { /* private fields */ }

Socks5 connection type Connect

This connection can be used as a regular async TCP stream after replying the client.

Implementations

impl<S: Default> Connect<S>

pub fn local_addr(&self) -> Result<SocketAddr>

Returns the local address that this stream is bound to.

pub fn peer_addr(&self) -> Result<SocketAddr>

Returns the remote address that this stream is connected to.

pub async fn shutdown(&mut self) -> Result<()>

Shutdown the TCP stream.

impl Connect<NeedReply>

pub async fn reply(self, reply: Reply, addr: Address) -> Result<Connect<Ready>>

Reply to the client.

impl Connect<Ready>

pub fn split(&mut self) -> (ReadHalf<'_>, WriteHalf<'_>)

Returns the read/write half of the stream.

pub fn into_split(self) -> (OwnedReadHalf, OwnedWriteHalf)

Returns the owned read/write half of the stream.

Methods from Deref<Target = TcpStream>

pub fn local_addr(&self) -> Result<SocketAddr, Error>

Returns the local address that this stream is bound to.

Examples

use tokio::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080").await?;

println!("{:?}", stream.local_addr()?);

pub fn take_error(&self) -> Result<Option<Error>, Error>

Returns the value of the SO_ERROR option.

pub fn peer_addr(&self) -> Result<SocketAddr, Error>

Returns the remote address that this stream is connected to.

Examples

use tokio::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080").await?;

println!("{:?}", stream.peer_addr()?);

pub fn poll_peek( &self, cx: &mut Context<'_>, buf: &mut ReadBuf<'_>, ) -> Poll<Result<usize, Error>>

Attempts to receive data on the socket, without removing that data from the queue, registering the current task for wakeup if data is not yet available.

Note that on multiple calls to poll_peek, poll_read or poll_read_ready, only the Waker from the Context passed to the most recent call is scheduled to receive a wakeup. (However, poll_write retains a second, independent waker.)

Return value

The function returns:

• Poll::Pending if data is not yet available.
• Poll::Ready(Ok(n)) if data is available. n is the number of bytes peeked.
• Poll::Ready(Err(e)) if an error is encountered.

Errors

This function may encounter any standard I/O error except WouldBlock.

Examples

use tokio::io::{self, ReadBuf};
use tokio::net::TcpStream;

use std::future::poll_fn;

#[tokio::main]
async fn main() -> io::Result<()> {
    let stream = TcpStream::connect("127.0.0.1:8000").await?;
    let mut buf = [0; 10];
    let mut buf = ReadBuf::new(&mut buf);

    poll_fn(|cx| {
        stream.poll_peek(cx, &mut buf)
    }).await?;

    Ok(())
}

pub async fn ready(&self, interest: Interest) -> Result<Ready, Error>

Waits for any of the requested ready states.

This function is usually paired with try_read() or try_write(). It can be used to concurrently read / write to the same socket on a single task without splitting the socket.

The function may complete without the socket being ready. This is a false-positive and attempting an operation will return with io::ErrorKind::WouldBlock. The function can also return with an empty Ready set, so you should always check the returned value and possibly wait again if the requested states are not set.

Cancel safety

This method is cancel safe. Once a readiness event occurs, the method will continue to return immediately until the readiness event is consumed by an attempt to read or write that fails with WouldBlock or Poll::Pending.

Examples

Concurrently read and write to the stream on the same task without splitting.

use tokio::io::Interest;
use tokio::net::TcpStream;
use std::error::Error;
use std::io;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    let stream = TcpStream::connect("127.0.0.1:8080").await?;

    loop {
        let ready = stream.ready(Interest::READABLE | Interest::WRITABLE).await?;

        if ready.is_readable() {
            let mut data = vec![0; 1024];
            // Try to read data, this may still fail with `WouldBlock`
            // if the readiness event is a false positive.
            match stream.try_read(&mut data) {
                Ok(n) => {
                    println!("read {} bytes", n);
                }
                Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                    continue;
                }
                Err(e) => {
                    return Err(e.into());
                }
            }

        }

        if ready.is_writable() {
            // Try to write data, this may still fail with `WouldBlock`
            // if the readiness event is a false positive.
            match stream.try_write(b"hello world") {
                Ok(n) => {
                    println!("write {} bytes", n);
                }
                Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                    continue
                }
                Err(e) => {
                    return Err(e.into());
                }
            }
        }
    }
}

pub async fn readable(&self) -> Result<(), Error>

Waits for the socket to become readable.

This function is equivalent to ready(Interest::READABLE) and is usually paired with try_read().

Cancel safety

This method is cancel safe. Once a readiness event occurs, the method will continue to return immediately until the readiness event is consumed by an attempt to read that fails with WouldBlock or Poll::Pending.

Examples

use tokio::net::TcpStream;
use std::error::Error;
use std::io;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // Connect to a peer
    let stream = TcpStream::connect("127.0.0.1:8080").await?;

    let mut msg = vec![0; 1024];

    loop {
        // Wait for the socket to be readable
        stream.readable().await?;

        // Try to read data, this may still fail with `WouldBlock`
        // if the readiness event is a false positive.
        match stream.try_read(&mut msg) {
            Ok(n) => {
                msg.truncate(n);
                break;
            }
            Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                continue;
            }
            Err(e) => {
                return Err(e.into());
            }
        }
    }

    println!("GOT = {:?}", msg);
    Ok(())
}

pub fn poll_read_ready(&self, cx: &mut Context<'_>) -> Poll<Result<(), Error>>

Polls for read readiness.

If the tcp stream is not currently ready for reading, this method will store a clone of the Waker from the provided Context. When the tcp stream becomes ready for reading, Waker::wake will be called on the waker.

Note that on multiple calls to poll_read_ready, poll_read or poll_peek, only the Waker from the Context passed to the most recent call is scheduled to receive a wakeup. (However, poll_write_ready retains a second, independent waker.)

This function is intended for cases where creating and pinning a future via readable is not feasible. Where possible, using readable is preferred, as this supports polling from multiple tasks at once.

Return value

The function returns:

• Poll::Pending if the tcp stream is not ready for reading.
• Poll::Ready(Ok(())) if the tcp stream is ready for reading.
• Poll::Ready(Err(e)) if an error is encountered.

Errors

This function may encounter any standard I/O error except WouldBlock.

pub fn try_read(&self, buf: &mut [u8]) -> Result<usize, Error>

Tries to read data from the stream into the provided buffer, returning how many bytes were read.

Receives any pending data from the socket but does not wait for new data to arrive. On success, returns the number of bytes read. Because try_read() is non-blocking, the buffer does not have to be stored by the async task and can exist entirely on the stack.

Usually, readable() or ready() is used with this function.

Return

If data is successfully read, Ok(n) is returned, where n is the number of bytes read. If n is 0, then it can indicate one of two scenarios:

1. The stream’s read half is closed and will no longer yield data.
2. The specified buffer was 0 bytes in length.

If the stream is not ready to read data, Err(io::ErrorKind::WouldBlock) is returned.

Examples

use tokio::net::TcpStream;
use std::error::Error;
use std::io;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // Connect to a peer
    let stream = TcpStream::connect("127.0.0.1:8080").await?;

    loop {
        // Wait for the socket to be readable
        stream.readable().await?;

        // Creating the buffer **after** the `await` prevents it from
        // being stored in the async task.
        let mut buf = [0; 4096];

        // Try to read data, this may still fail with `WouldBlock`
        // if the readiness event is a false positive.
        match stream.try_read(&mut buf) {
            Ok(0) => break,
            Ok(n) => {
                println!("read {} bytes", n);
            }
            Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                continue;
            }
            Err(e) => {
                return Err(e.into());
            }
        }
    }

    Ok(())
}

pub fn try_read_vectored( &self, bufs: &mut [IoSliceMut<'_>], ) -> Result<usize, Error>

Tries to read data from the stream into the provided buffers, returning how many bytes were read.

Data is copied to fill each buffer in order, with the final buffer written to possibly being only partially filled. This method behaves equivalently to a single call to try_read() with concatenated buffers.

Receives any pending data from the socket but does not wait for new data to arrive. On success, returns the number of bytes read. Because try_read_vectored() is non-blocking, the buffer does not have to be stored by the async task and can exist entirely on the stack.

Usually, readable() or ready() is used with this function.

Return

If data is successfully read, Ok(n) is returned, where n is the number of bytes read. Ok(0) indicates the stream’s read half is closed and will no longer yield data. If the stream is not ready to read data Err(io::ErrorKind::WouldBlock) is returned.

Examples

use tokio::net::TcpStream;
use std::error::Error;
use std::io::{self, IoSliceMut};

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // Connect to a peer
    let stream = TcpStream::connect("127.0.0.1:8080").await?;

    loop {
        // Wait for the socket to be readable
        stream.readable().await?;

        // Creating the buffer **after** the `await` prevents it from
        // being stored in the async task.
        let mut buf_a = [0; 512];
        let mut buf_b = [0; 1024];
        let mut bufs = [
            IoSliceMut::new(&mut buf_a),
            IoSliceMut::new(&mut buf_b),
        ];

        // Try to read data, this may still fail with `WouldBlock`
        // if the readiness event is a false positive.
        match stream.try_read_vectored(&mut bufs) {
            Ok(0) => break,
            Ok(n) => {
                println!("read {} bytes", n);
            }
            Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                continue;
            }
            Err(e) => {
                return Err(e.into());
            }
        }
    }

    Ok(())
}

pub fn try_read_buf<B>(&self, buf: &mut B) -> Result<usize, Error>

where B: BufMut,

Tries to read data from the stream into the provided buffer, advancing the buffer’s internal cursor, returning how many bytes were read.

Receives any pending data from the socket but does not wait for new data to arrive. On success, returns the number of bytes read. Because try_read_buf() is non-blocking, the buffer does not have to be stored by the async task and can exist entirely on the stack.

Usually, readable() or ready() is used with this function.

Return

If data is successfully read, Ok(n) is returned, where n is the number of bytes read. Ok(0) indicates the stream’s read half is closed and will no longer yield data. If the stream is not ready to read data Err(io::ErrorKind::WouldBlock) is returned.

Examples

use tokio::net::TcpStream;
use std::error::Error;
use std::io;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // Connect to a peer
    let stream = TcpStream::connect("127.0.0.1:8080").await?;

    loop {
        // Wait for the socket to be readable
        stream.readable().await?;

        let mut buf = Vec::with_capacity(4096);

        // Try to read data, this may still fail with `WouldBlock`
        // if the readiness event is a false positive.
        match stream.try_read_buf(&mut buf) {
            Ok(0) => break,
            Ok(n) => {
                println!("read {} bytes", n);
            }
            Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                continue;
            }
            Err(e) => {
                return Err(e.into());
            }
        }
    }

    Ok(())
}

pub async fn writable(&self) -> Result<(), Error>

Waits for the socket to become writable.

This function is equivalent to ready(Interest::WRITABLE) and is usually paired with try_write().

Cancel safety

This method is cancel safe. Once a readiness event occurs, the method will continue to return immediately until the readiness event is consumed by an attempt to write that fails with WouldBlock or Poll::Pending.

Examples

use tokio::net::TcpStream;
use std::error::Error;
use std::io;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // Connect to a peer
    let stream = TcpStream::connect("127.0.0.1:8080").await?;

    loop {
        // Wait for the socket to be writable
        stream.writable().await?;

        // Try to write data, this may still fail with `WouldBlock`
        // if the readiness event is a false positive.
        match stream.try_write(b"hello world") {
            Ok(n) => {
                break;
            }
            Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                continue;
            }
            Err(e) => {
                return Err(e.into());
            }
        }
    }

    Ok(())
}

pub fn poll_write_ready(&self, cx: &mut Context<'_>) -> Poll<Result<(), Error>>

Polls for write readiness.

If the tcp stream is not currently ready for writing, this method will store a clone of the Waker from the provided Context. When the tcp stream becomes ready for writing, Waker::wake will be called on the waker.

Note that on multiple calls to poll_write_ready or poll_write, only the Waker from the Context passed to the most recent call is scheduled to receive a wakeup. (However, poll_read_ready retains a second, independent waker.)

This function is intended for cases where creating and pinning a future via writable is not feasible. Where possible, using writable is preferred, as this supports polling from multiple tasks at once.

Return value

The function returns:

• Poll::Pending if the tcp stream is not ready for writing.
• Poll::Ready(Ok(())) if the tcp stream is ready for writing.
• Poll::Ready(Err(e)) if an error is encountered.

Errors

This function may encounter any standard I/O error except WouldBlock.

pub fn try_write(&self, buf: &[u8]) -> Result<usize, Error>

Try to write a buffer to the stream, returning how many bytes were written.

The function will attempt to write the entire contents of buf, but only part of the buffer may be written.

This function is usually paired with writable().

Return

If data is successfully written, Ok(n) is returned, where n is the number of bytes written. If the stream is not ready to write data, Err(io::ErrorKind::WouldBlock) is returned.

Examples

use tokio::net::TcpStream;
use std::error::Error;
use std::io;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // Connect to a peer
    let stream = TcpStream::connect("127.0.0.1:8080").await?;

    loop {
        // Wait for the socket to be writable
        stream.writable().await?;

        // Try to write data, this may still fail with `WouldBlock`
        // if the readiness event is a false positive.
        match stream.try_write(b"hello world") {
            Ok(n) => {
                break;
            }
            Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                continue;
            }
            Err(e) => {
                return Err(e.into());
            }
        }
    }

    Ok(())
}

pub fn try_write_vectored(&self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Tries to write several buffers to the stream, returning how many bytes were written.

Data is written from each buffer in order, with the final buffer read from possible being only partially consumed. This method behaves equivalently to a single call to try_write() with concatenated buffers.

This function is usually paired with writable().

Return

If data is successfully written, Ok(n) is returned, where n is the number of bytes written. If the stream is not ready to write data, Err(io::ErrorKind::WouldBlock) is returned.

Examples

use tokio::net::TcpStream;
use std::error::Error;
use std::io;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // Connect to a peer
    let stream = TcpStream::connect("127.0.0.1:8080").await?;

    let bufs = [io::IoSlice::new(b"hello "), io::IoSlice::new(b"world")];

    loop {
        // Wait for the socket to be writable
        stream.writable().await?;

        // Try to write data, this may still fail with `WouldBlock`
        // if the readiness event is a false positive.
        match stream.try_write_vectored(&bufs) {
            Ok(n) => {
                break;
            }
            Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                continue;
            }
            Err(e) => {
                return Err(e.into());
            }
        }
    }

    Ok(())
}

pub fn try_io<R>( &self, interest: Interest, f: impl FnOnce() -> Result<R, Error>, ) -> Result<R, Error>

Tries to read or write from the socket using a user-provided IO operation.

If the socket is ready, the provided closure is called. The closure should attempt to perform IO operation on the socket by manually calling the appropriate syscall. If the operation fails because the socket is not actually ready, then the closure should return a WouldBlock error and the readiness flag is cleared. The return value of the closure is then returned by try_io.

If the socket is not ready, then the closure is not called and a WouldBlock error is returned.

The closure should only return a WouldBlock error if it has performed an IO operation on the socket that failed due to the socket not being ready. Returning a WouldBlock error in any other situation will incorrectly clear the readiness flag, which can cause the socket to behave incorrectly.

The closure should not perform the IO operation using any of the methods defined on the Tokio TcpStream type, as this will mess with the readiness flag and can cause the socket to behave incorrectly.

This method is not intended to be used with combined interests. The closure should perform only one type of IO operation, so it should not require more than one ready state. This method may panic or sleep forever if it is called with a combined interest.

Usually, readable(), writable() or ready() is used with this function.

pub async fn async_io<R>( &self, interest: Interest, f: impl FnMut() -> Result<R, Error>, ) -> Result<R, Error>

Reads or writes from the socket using a user-provided IO operation.

The readiness of the socket is awaited and when the socket is ready, the provided closure is called. The closure should attempt to perform IO operation on the socket by manually calling the appropriate syscall. If the operation fails because the socket is not actually ready, then the closure should return a WouldBlock error. In such case the readiness flag is cleared and the socket readiness is awaited again. This loop is repeated until the closure returns an Ok or an error other than WouldBlock.

The closure should only return a WouldBlock error if it has performed an IO operation on the socket that failed due to the socket not being ready. Returning a WouldBlock error in any other situation will incorrectly clear the readiness flag, which can cause the socket to behave incorrectly.

The closure should not perform the IO operation using any of the methods defined on the Tokio TcpStream type, as this will mess with the readiness flag and can cause the socket to behave incorrectly.

This method is not intended to be used with combined interests. The closure should perform only one type of IO operation, so it should not require more than one ready state. This method may panic or sleep forever if it is called with a combined interest.

pub async fn peek(&self, buf: &mut [u8]) -> Result<usize, Error>

Receives data on the socket from the remote address to which it is connected, without removing that data from the queue. On success, returns the number of bytes peeked.

Successive calls return the same data. This is accomplished by passing MSG_PEEK as a flag to the underlying recv system call.

Examples

use tokio::net::TcpStream;
use tokio::io::AsyncReadExt;
use std::error::Error;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // Connect to a peer
    let mut stream = TcpStream::connect("127.0.0.1:8080").await?;

    let mut b1 = [0; 10];
    let mut b2 = [0; 10];

    // Peek at the data
    let n = stream.peek(&mut b1).await?;

    // Read the data
    assert_eq!(n, stream.read(&mut b2[..n]).await?);
    assert_eq!(&b1[..n], &b2[..n]);

    Ok(())
}

The read method is defined on the AsyncReadExt trait.

pub fn nodelay(&self) -> Result<bool, Error>

Gets the value of the TCP_NODELAY option on this socket.

For more information about this option, see set_nodelay.

Examples

use tokio::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080").await?;

println!("{:?}", stream.nodelay()?);

pub fn set_nodelay(&self, nodelay: bool) -> Result<(), Error>

Sets the value of the TCP_NODELAY option on this socket.

If set, this option disables the Nagle algorithm. This means that segments are always sent as soon as possible, even if there is only a small amount of data. When not set, data is buffered until there is a sufficient amount to send out, thereby avoiding the frequent sending of small packets.

Examples

use tokio::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080").await?;

stream.set_nodelay(true)?;

pub fn linger(&self) -> Result<Option<Duration>, Error>

Reads the linger duration for this socket by getting the SO_LINGER option.

For more information about this option, see set_linger.

Examples

use tokio::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080").await?;

println!("{:?}", stream.linger()?);

pub fn set_linger(&self, dur: Option<Duration>) -> Result<(), Error>

Sets the linger duration of this socket by setting the SO_LINGER option.

This option controls the action taken when a stream has unsent messages and the stream is closed. If SO_LINGER is set, the system shall block the process until it can transmit the data or until the time expires.

If SO_LINGER is not specified, and the stream is closed, the system handles the call in a way that allows the process to continue as quickly as possible.

Examples

use tokio::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080").await?;

stream.set_linger(None)?;

pub fn ttl(&self) -> Result<u32, Error>

Gets the value of the IP_TTL option for this socket.

For more information about this option, see set_ttl.

Examples

use tokio::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080").await?;

println!("{:?}", stream.ttl()?);

pub fn set_ttl(&self, ttl: u32) -> Result<(), Error>

Sets the value for the IP_TTL option on this socket.

This value sets the time-to-live field that is used in every packet sent from this socket.

Examples

use tokio::net::TcpStream;

let stream = TcpStream::connect("127.0.0.1:8080").await?;

stream.set_ttl(123)?;

pub fn split<'a>(&'a mut self) -> (ReadHalf<'a>, WriteHalf<'a>)

Splits a TcpStream into a read half and a write half, which can be used to read and write the stream concurrently.

This method is more efficient than into_split, but the halves cannot be moved into independently spawned tasks.

Trait Implementations

impl AsyncRead for Connect<Ready>

fn poll_read( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &mut ReadBuf<'_>, ) -> Poll<Result<()>>

Attempts to read from the AsyncRead into buf.

impl AsyncWrite for Connect<Ready>

fn poll_write( self: Pin<&mut Self>, cx: &mut Context<'_>, buf: &[u8], ) -> Poll<Result<usize>>

Attempt to write bytes from buf into the object.

fn poll_write_vectored( self: Pin<&mut Self>, cx: &mut Context<'_>, bufs: &[IoSlice<'_>], ) -> Poll<Result<usize>>

Like poll_write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

Determines if this writer has an efficient poll_write_vectored implementation.

fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

Attempts to flush the object, ensuring that any buffered data reach their destination.

fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>

Initiates or attempts to shut down this writer, returning success when the I/O connection has completely shut down.

impl<S: Debug> Debug for Connect<S>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for Connect<Ready>

type Target = TcpStream

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl DerefMut for Connect<Ready>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<S> From<Connect<S>> for TcpStream

fn from(conn: Connect<S>) -> Self

Converts to this type from the input type.