This is a UDP echo server demo program. Unlike conventional UDP programs, the server and the client in this program are located in different network namespace. Two different network namespaces are connected by a bridge br0 created by OpenvSwitch.

The program works very simple: the client (C) sends a Hello from client message, and the server (S) replies with a Hello from server message.

这是一个 UDP Hello World 示例代码，其效果十分简单：客户端（C）发送 Hello from client 消息，服务器（S）收到后回复 Hello from server 消息。

但与常规 UDP socket 不同，客户端 C 和服务端 S 均处于隔离的 Network namespace 中，两个隔离的网络空间通过 OpenvSwitch 交换机连接。如上图所示

Here we use ovs instead of linux bridge, and you can still use linux bridge just with some small modifications of the source code if you really want.

$ git clone [email protected]:yanjiulab/isolate-socket.git

# create br0
$ sudo apt install openvswitch-switch  # suppose you are a ubuntu user
$ sudo ./config  

# compile
$ make

# run
$ sudo ./isolate_server  # in one terminal
Server start at 10.0.0.2:8080... 
Client[10.0.0.1:60859] : Hello from client
Hello message sent.
 
$ sudo ./isolate_client  # in another terminal
Hello message sent.
Server[10.0.0.2:8080] : Hello from server

• UDP Server-Client implementation in C
• A deep dive into Linux namespaces, part 4, source code here