UDP communication

We have discussed how to communicate through TCP enough, so it is time to switch to UDP now. UDP is a connectionless protocol, and it is easier to use than TCP. There is a client/server example. Below is client code: 

  1. #include <boost/asio.hpp>
  2. #include <iostream>
  4. int main()
  5. {
  6.     try
  7.     {
  8.         boost::asio::io_context io_context;
  10.         boost::asio::ip::udp::socket socket{io_context};
  11.         socket.open(boost::asio::ip::udp::v4());
  13.         socket.send_to(
  14.                 boost::asio::buffer("Hello world!"),
  15.                 boost::asio::ip::udp::endpoint{boost::asio::ip::make_address("192.168.35.145"), 3303});
  16.     }
  17.     catch (std::exception& e)
  18.     {
  19.         std::cerr << e.what() << '\n';
  20.         return -1;
  21.     }
  23.     return 0;
  24. }

Although there is no need to call socket.connect function, you need call socket.open explicitly. Furthermore, the server’s endpoint needs to be specified when invoking socket.send_to.

Server code is like this: 

  1. #include <ctime>
  2. #include <functional>
  3. #include <iostream>
  4. #include <string>
  5. #include <boost/asio.hpp>
  7. int main()
  8. {
  9.     try
  10.     {
  11.         boost::asio::io_context io_context;
  13.         for (;;)
  14.         {
  15.             boost::asio::ip::udp::socket socket(
  16.                     io_context,
  17.                     boost::asio::ip::udp::endpoint{boost::asio::ip::udp::v4(), 3303});
  19.             boost::asio::ip::udp::endpoint client;
  20.             char recv_str[1024] = {};
  22.             socket.receive_from(
  23.                     boost::asio::buffer(recv_str),
  24.                     client);
  25.             std::cout << client << ": " << recv_str << '\n';
  26.         }
  27.     }
  28.     catch (std::exception& e)
  29.     {
  30.         std::cerr << e.what() << std::endl;
  31.     }
  33.     return 0;
  34. }

Very easy, isn’t it? Build and run client and server. The following log will be printed on server side: 

  1. $ ./server
  2. 10.217.242.21:63838: Hello world!
  3. 10.217.242.21:61259: Hello world!