A tun2socks implementation written in Go.

Tested and worked on macOS, Linux and iOS (as a library).

                                      lwip.Setup()
                                           +
                                           |
                                           |
                                           |
                                           |                TCP/UDP             lwip.RegisterTCPConnectionHandler()
                                           |
                          lwip.Input()     |           tun2socks.Connection     lwip.RegisterUDPConnectionHandler()
                                           v
Application +------> TUN +-----------> lwIP stack +------------------------------> tun2socks.ConnectionHandler +-------> SOCKS5 server +--> Destination


                         <-----------+
                    lwip.RegisterOutputFn()

• Support both TCP and UDP (only IPv4 for now)
• SOCKS5 proxing (both TCP and UDP)
• UDP direct relaying (no proxy)
• ICMP local echoing

go get github.com/eycorsican/go-tun2socks
cd $GOPATH/src/github.com/eycorsican/go-tun2socks
go get -d ./...
make clean && make build
./build/tun2socks -h

Note that the name tun1 maybe not available, make sure use ifconfig or ip addr to check it out.

./build/tun2socks -tunName tun1 -tunAddr 240.0.0.2 -tunGw 240.0.0.1 -proxyType socks -proxyServer 1.2.3.4:1086

Suppose your original gateway is 192.168.0.1. The proxy server address is 1.2.3.4.

The following commands will need root permissions.

The program will automatically create a tun device for you on macOS. To show the created tun device, use ifconfig.

Delete original gateway:

route delete default

Add our tun interface as the default gateway:

route add default 240.0.0.2

Add a route for your proxy server to bypass the tun interface:

route add 1.2.3.4/32 192.168.0.1

The program will not create the tun device for you on Linux. You need to create the tun device by yourself:

ip tuntap add mode tun dev tun1
ip addr add 240.0.0.2 dev tun1
ip link set dev tun1 up

Delete original gateway:

ip route del default

Add our tun interface as the default gateway:

ip route add default via 240.0.0.2

Add a route for your proxy server to bypass the tun interface:

ip route add 1.2.3.4/32 via 192.168.0.1

Take a look at this repo: https://github.com/eycorsican/lwip

• https://github.com/zhuhaow/tun2socks
• https://github.com/yinghuocho/gotun2socks
• https://github.com/shadowsocks/go-shadowsocks2
• https://github.com/nadoo/glider