udp-over-tcp

proxy UDP traffic over a TCP stream.

A library (and binaries) for tunneling UDP datagrams over a TCP stream.

Some programs/protocols only work over UDP. And some networks only allow TCP. This is where udp-over-tcp comes in handy. This library comes in two parts:

• udp2tcp - Forwards incoming UDP datagrams over a TCP stream. The return stream is translated back to datagrams and sent back out over UDP again. This part can be easily used as both a library and a binary. So it can be run standalone, but can also easily be included in other Rust programs. The UDP socket is connected to the peer address of the first incoming datagram. So one [Udp2Tcp] instance can handle traffic from a single peer only.
• tcp2udp - Accepts connections over TCP and translates + forwards the incoming stream as UDP datagrams to the destination specified during setup / on the command line. Designed mostly to be a standalone executable to run on servers. But can be consumed as a Rust library as well. tcp2udp continues to accept new incoming TCP connections, and creates a new UDP socket for each. So a single tcp2udp server can be used to service many udp2tcp clients.

Protocol

The format of the data inside the TCP stream is very simple. Each datagram is preceded with a 16 bit unsigned integer in big endian byte order, specifying the length of the datagram.

tcp2udp server example

Make the server listen for TCP connections that it can then forward to a local UDP service. This will listen on 10.0.0.1:5001/TCP and forward anything that comes in to 127.0.0.1:51820/UDP:

user@server $ RUST_LOG=debug tcp2udp \
    --tcp-listen 10.0.0.0:5001 \
    --udp-forward 127.0.0.1:51820

RUST_LOG can be used to set logging level. See documentation for env_logger for information. The crate must be built with the env_logger feature for this to be active.

REDACT_LOGS=1 can be set to redact the IPs of the peers using the service from the logs. Allows having logging turned on but without storing potentially user sensitive data to disk.

udp2tcp example

This is one way you could integrate udp2tcp into your Rust program. This will connect a TCP socket to 1.2.3.4:9000 and bind a UDP socket to a random port on the loopback interface. It will then connect the UDP socket to the socket addr of the first incoming datagram and start forwarding all traffic to (and from) the TCP socket.

from https://github.com/mullvad/udp-over-tcp

(类似于github.com/wangyu-/udp2raw)

-----

我的补充说明：

先设置cargo的代理：
nano ~/.cargo/config
cat ~/.cargo/config
显示：
[http]
proxy = 'http://127.0.0.1:8788'
[https]
proxy = 'http://127.0.0.1:8788'

然后，

git clone https://github.com/mullvad/udp-over-tcp udp-over-tcp-by-mullvad

cd udp-over-tcp-by-mullvad

cargo build --release

cd target/release

./udp2tcp -h

显示：

udp2tcp 0.1.0

Options to apply to the TCP socket involved in the tunneling

USAGE:

    udp2tcp [OPTIONS] --tcp-forward <tcp-forward-addr> --udp-listen <udp-listen-addr>

FLAGS:

    -h, --help       Prints help information

    -V, --version    Prints version information

OPTIONS:

        --recv-buffer <recv-buffer-size>    If given, sets the SO_RCVBUF option on the TCP socket to the given number of

                                            bytes. Changes the size of the operating system's receive buffer associated

                                            with the socket

        --send-buffer <send-buffer-size>    If given, sets the SO_SNDBUF option on the TCP socket to the given number of

                                            bytes. Changes the size of the operating system's send buffer associated

                                            with the socket

        --tcp-forward <tcp-forward-addr>    The IP and TCP port to forward all UDP traffic to

        --udp-listen <udp-listen-addr>      The IP and UDP port to bind to and accept incoming connections on