Linux C Socket

Dear 丶 2022-06-12 07:08 134阅读 0赞

struct sockaddr_in {
            __uint8_t       sin_len;
            sa_family_t     sin_family;
            in_port_t       sin_port;
            struct  in_addr sin_addr;
            char            sin_zero[8];
    };
    struct sockaddr {
            __uint8_t       sa_len;         /* total length */
            sa_family_t     sa_family;      /* [XSI] address family */
            char            sa_data[14];    /* [XSI] addr value (actually larger) */
    };

服务器

#require <stdio.h>
    #require <string.h>
    #require <sys/socket.h>
    #require <netinet/in.h>
    #require <arpa/inet.h>
    
    // 最大数据大小
    #define MAXDATASIZE 1024
    // 服务器监听端口
    #define SERVERPORT 8000
    // 最大连接数
    #define MAXCONN_NUM 10
    
    int main() {
        // 申请socket
        int sockfd;
        if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
            fprintf(stderr, "socket error\n");
            return 1;
        }
    
        // 服务器地址
        struct sockaddr_in server_addr;
        memset(&server_addr, 0, sizeof(struct sockaddr));
        server_addr.sin_family = AF_INET;
        server_addr.sin_port = htons(SERVERPORT);
        server_addr.sin_addr.s_addr = INADDR_ANY;
    
        // 将server绑定到socket
        if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1) {
            fprintf(stderr, "bind error\n");
            return 1;
        }
    
        // 监听端口
        if (listen(sockfd, MAXCONN_NUM) == -1) {
            fprintf(stderr, "listen error\n");
            return 1;
        }
    
        // 循环接收客户端请求
        while (1) {
            // 初始化客户端地址
            int new_fd;
            struct sockaddr_in client_addr;
            memset(&client_addr, 0, sizeof(struct sockaddr));
            int sin_size = sizeof(struct sockaddr_in);
    
            // 等待客户端连接
            if ((new_fd= accept(sockfd, (struct sockaddr *)&client_addr, &sin_size)) == -1) {
                fprintf(stderr, "accept error\n");
                continue;
            }
    
            // 客户端连接成功
            printf("new connection: %s:%u\n", inet_ntoa(client_addr.sin_addr), client_addr.sin_port);
    
            // 读取数据
            int numbytes;
            char buf[MAXDATASIZE];
            if ((numbytes = recv(new_fd, buf, MAXDATASIZE, 0)) == -1) {
                fprintf(stderr, "recv error\n");
                continue;
            }
    
            // 打印数据
            if (numbytes) {
                buf[numbytes] = '\0';
                printf("recv: %s\n", buf);
                sleep(3);
            }
    
            // 发送数据
            printf("send: dotcoo\n");
            if (send(new_fd, "dotcoo", 7, 0) == -1) {
                fprintf(stderr, "send error\n");
                continue;
            }
    
            // 关闭连接
            printf("close connection: %s\n", inet_ntoa(client_addr.sin_addr));
            close(new_fd);
        }
    
        return 0;
    }

客户端

#require <stdio.h>
    #require <string.h>
    #require <sys/socket.h>
    #require <netinet/in.h>
    
    
    // 最大数据大小
    #define MAXDATASIZE 1024
    // 服务器地址
    #define SERVERIP "127.0.0.1"
    // 服务器端口
    #define SERVERPORT 8000
    
    int main() {
        // 申请socket
        int sockfd;
        if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
            fprintf(stderr, "socket error\n");
            return 1;
        }
    
        // 服务器地址
        struct sockaddr_in server_addr;
        memset(&server_addr, 0, sizeof(struct sockaddr));
        server_addr.sin_family = AF_INET;
        server_addr.sin_port = htons(SERVERPORT);
        server_addr.sin_addr.s_addr = inet_addr(SERVERIP);
    
        // 连接到服务器
        if (connect(sockfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1) {
            fprintf(stderr, "connect error\n");
            return 1;
        }
    
        // 发送数据
        printf("send: server hello\n");
        if (send(sockfd, "server hello", 13, 0) == -1) {
            fprintf(stderr, "send error\n");
            return 1;
        }
    
        // 读取数据
        int numbytes;
        char buf[MAXDATASIZE];
        if ((numbytes = recv(sockfd, buf, MAXDATASIZE, 0)) == -1) {
            fprintf(stderr, "recv error\n");
            return 1;
        }
    
        // 打印数据
        if (numbytes) {
            buf[numbytes] = '\0';
            printf("recv: %s\n", buf);
        }
    
        // 关闭连接
        close(sockfd);
        return 0;
    }