socket基本连接

基本操作

服务端

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

int main(int argc, char* argv[])
{
    std::cout << "begin" << std::endl;
    //1.创建一个侦听socket
    int listenfd = socket(AF_INET, SOCK_STREAM, 0);
    if (listenfd == -1)
    {
        std::cout << "create listen socket error." << std::endl;
        return -1;
    }

    //2.初始化服务器地址
    struct sockaddr_in bindaddr;
    bindaddr.sin_family = AF_INET;
    bindaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    bindaddr.sin_port = htons(3000);
    if (bind(listenfd, (struct sockaddr *)&bindaddr, sizeof(bindaddr)) == -1)
    {
        std::cout << "bind listen socket error." << std::endl;
        close(listenfd);
        return -1;
    }

    //3.启动侦听
    if (listen(listenfd, SOMAXCONN) == -1)
    {
        std::cout << "listen error." << std::endl;
        close(listenfd);
        return -1;
    }

    while (true)
    {
        struct sockaddr_in clientaddr;
        socklen_t clientaddrlen = sizeof(clientaddr);
        //4. 接受客户端连接
        int clientfd = accept(listenfd, (struct sockaddr *)&clientaddr, &clientaddrlen);
        if (clientfd != -1)
        {             
            char recvBuf[32] = {0};
            //5. 从客户端接受数据
            int ret = recv(clientfd, recvBuf, 32, 0);
            if (ret > 0) 
            {
                std::cout << "recv data from client, data: " << recvBuf << std::endl;
                //6. 将收到的数据原封不动地发给客户端
                ret = send(clientfd, recvBuf, strlen(recvBuf), 0);
                if (ret != strlen(recvBuf))
                    std::cout << "send data error." << std::endl;
                else
                    std::cout << "send data to client successfully, data: " << recvBuf << std::endl;
            } 
            else 
            {
                std::cout << "recv data error." << std::endl;
            }

            close(clientfd);
        }
    }

    //7.关闭侦听socket
    close(listenfd);

    return 0;
}

客户端

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

#define SERVER_ADDRESS "192.168.200.144"
#define SERVER_PORT     3000
#define SEND_DATA       "helloworld"

int main(int argc, char* argv[])
{
    //1.创建一个socket
    int clientfd = socket(AF_INET, SOCK_STREAM, 0);
    if (clientfd == -1)
    {
        std::cout << "create client socket error." << std::endl;
        return -1;
    }

    //2.连接服务器
    struct sockaddr_in serveraddr;
    serveraddr.sin_family = AF_INET;
    serveraddr.sin_addr.s_addr = inet_addr(SERVER_ADDRESS);
    serveraddr.sin_port = htons(SERVER_PORT);
    if (connect(clientfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) == -1)
    {
        std::cout << "connect socket error." << std::endl;
        close(clientfd);
        return -1;
    }

    //3. 向服务器发送数据
    int ret = send(clientfd, SEND_DATA, strlen(SEND_DATA), 0);
    if (ret != strlen(SEND_DATA))
    {
        std::cout << "send data error." << std::endl;
        close(clientfd);
        return -1;
    }

    std::cout << "send data successfully, data: " << SEND_DATA << std::endl;

    //4. 从服务器收取数据
    char recvBuf[32] = {0};
    ret = recv(clientfd, recvBuf, 32, 0);
    if (ret > 0) 
    {
        std::cout << "recv data successfully, data: " << recvBuf << std::endl;
    } 
    else 
    {
        std::cout << "recv data error, data: " << recvBuf << std::endl;
    }

    //5. 关闭socket
    close(clientfd);

    return 0;
}