C/C++网络编程6——实现基于UDP的服务器端/客户端

服务器端：

#include <iostream>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <unistd.h>
#include <cstring>

const unsigned int BUFFER_SIZE = 1024;

int main()
{
    // step1：创建UDP套接字
    int ser_socket = socket(PF_INET, SOCK_DGRAM, 0);
    if (ser_socket == -1) {
        std::cout << "socket failed" << std::endl;
        return 0;
    }

    // step2：绑定ip地址和端口号
    sockaddr_in ser_addr;
    memset(&ser_addr, 0, sizeof(ser_addr));
    ser_addr.sin_family = AF_INET;
    ser_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    ser_addr.sin_port = htons(9999);
    if (bind(ser_socket, (sockaddr *)(&ser_addr), sizeof(ser_addr)) == -1) {
        std::cout << "bind failed" << std::endl;
        close(ser_socket);
        return 0;
    }

    char message[BUFFER_SIZE];
    sockaddr_in client_addr;
    socklen_t client_addr_len = sizeof(client_addr_len);
    int message_len = recvfrom(ser_socket, message, BUFFER_SIZE, 0, 
        (sockaddr*)(&client_addr), &client_addr_len);
    std::cout << message << std::endl;

    sendto(ser_socket, message, message_len, 0, 
        (sockaddr *)(&client_addr), client_addr_len);
    close(ser_socket);
    return 0;
}

客户端：

#include <iostream>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <unistd.h>
#include <cstring>

const unsigned int BUFFER_SIZE = 1024;

int main()
{
    // 创建UDP套接字
    int client_sock = socket(PF_INET, SOCK_DGRAM, 0);
    if (client_sock == -1) {
        std::cout << "socket failed" << std::endl;
        return 0;
    }

    sockaddr_in ser_addr;
    memset(&ser_addr, 0, sizeof(ser_addr));
    ser_addr.sin_family = AF_INET;
    ser_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
    ser_addr.sin_port = htons(9999);
    
    char info[] = "i love china";
    sendto(client_sock, info, sizeof(info), 0, 
        (sockaddr *)(&ser_addr), sizeof(ser_addr));

    char message[BUFFER_SIZE];
    sockaddr_in from_addr;
    socklen_t from_addr_len = sizeof(from_addr);
    recvfrom(client_sock, message, BUFFER_SIZE, 0, 
        (sockaddr*)(&from_addr), &from_addr_len);

    std::cout << message << std::endl;
    close(client_sock);
    return 0;
}