TCP通信实现（服务器端)

案例

// TCP 通信的服务器端
#include 
#include 
#include 
#include 
#include 
int main() {
    // 1.创建socket(用于监听的套接字)
    int lfd = socket(AF_INET, SOCK_STREAM, 0);
    if(lfd == -1) {
        perror("socket");
        exit(-1);
    }
    // 2.绑定
    #include 
// struct sockaddr_in
// {
// sa_family_t sin_family; /* __SOCKADDR_COMMON(sin_) */
// in_port_t sin_port; /* Port number. */
// struct in_addr sin_addr; /* Internet address. */
// /* Pad to size of `struct sockaddr'. */
// unsigned char sin_zero[sizeof (struct sockaddr) - __SOCKADDR_COMMON_SIZE -
// sizeof (in_port_t) - sizeof (struct in_addr)];
// };
// struct in_addr
// {
// 	in_addr_t s_addr;
// };
    struct sockaddr_in saddr;
    saddr.sin_family = AF_INET;
    // inet_pton(AF_INET, "192.168.193.128", saddr.sin_addr.s_addr);
    saddr.sin_addr.s_addr = INADDR_ANY;  // 0.0.0.0 表示任意地址，计算机有多个网卡，每个网卡ip地址可能都不一样。只有服务端可以这样写
    saddr.sin_port = htons(9999);//将一个短整型数从主机字节序转换到网络字节序。
    int ret = bind(lfd, (struct sockaddr *)&saddr, sizeof(saddr));
    if(ret == -1) {
        perror("bind");
        exit(-1);
    }
    // 3.监听
    ret = listen(lfd, 8);
    if(ret == -1) {
        perror("listen");
        exit(-1);
    }
    // 4.接收客户端连接
    struct sockaddr_in clientaddr;
    int len = sizeof(clientaddr);
    //是一个阻塞的函数 
    int cfd = accept(lfd, (struct sockaddr *)&clientaddr, &len);
    
    if(cfd == -1) {
        perror("accept");
        exit(-1);
    }
    // 输出客户端的信息
    char clientIP[16];
    inet_ntop(AF_INET, &clientaddr.sin_addr.s_addr, clientIP, sizeof(clientIP));//网络字节序转主机字节序。ip地址转换
    unsigned short clientPort = ntohs(clientaddr.sin_port);//网络字节序转主机字节序，端口号转换
    printf("client ip is %s, port is %d\n", clientIP, clientPort);
    // 5.通信
    char recvBuf[1024] = {0};
    while(1) {
        
        // 获取客户端的数据
        int num = read(cfd, recvBuf, sizeof(recvBuf));
        if(num == -1) {
            perror("read");
            exit(-1);
        } else if(num > 0) {
            printf("recv client data : %s\n", recvBuf);
        } else if(num == 0) {
            // 表示客户端断开连接
            printf("clinet closed...");
            break;
        }
        char * data = "hello,i am server";
        // 给客户端发送数据
        write(cfd, data, strlen(data));
    }
   
    // 关闭文件描述符
    close(cfd);
    close(lfd);
    return 0;
}

TCP通信实现（客户端）

案例

// TCP通信的客户端
#include 
#include 
#include 
#include 
#include 
int main() {
    // 1.创建套接字
    int fd = socket(AF_INET, SOCK_STREAM, 0);
    if(fd == -1) {
        perror("socket");
        exit(-1);
    }
    // 2.连接服务器端
    struct sockaddr_in serveraddr;
    serveraddr.sin_family = AF_INET;
    inet_pton(AF_INET, "192.168.128.128", &serveraddr.sin_addr.s_addr);
    serveraddr.sin_port = htons(9999);
    int ret = connect(fd, (struct sockaddr *)&serveraddr, sizeof(serveraddr));
    if(ret == -1) {
        perror("connect");
        exit(-1);
    }
    
    // 3. 通信
    char recvBuf[1024] = {0};
    while(1) {
        char * data = "hello,i am client";
        // 给客户端发送数据
        write(fd, data , strlen(data));
        sleep(1);
        
        int len = read(fd, recvBuf, sizeof(recvBuf));
        if(len == -1) {
            perror("read");
            exit(-1);
        } else if(len > 0) {
            printf("recv server data : %s\n", recvBuf);
        } else if(len == 0) {
            // 表示服务器端断开连接
            printf("server closed...");
            break;
        }
    }
    // 关闭连接
    close(fd);
    return 0;
}

daic@daic:~/Linux/linuxwebserver/part04networkProgramming/lesson32$ ./client 
recv server data : hello,i am server
recv server data : hello,i am server
recv server data : hello,i am server
recv server data : hello,i am server
recv server data : hello,i am server
recv server data : hello,i am server

daic@daic:~/Linux/linuxwebserver/part04networkProgramming/lesson32$ ./server 
client ip is 192.168.128.128, port is 54410
recv client data : hello,i am client
recv client data : hello,i am client
recv client data : hello,i am client
recv client data : hello,i am client
recv client data : hello,i am client
recv client data : hello,i am client
recv client data : hello,i am client
recv client data : hello,i am client
recv client data : hello,i am client