简单的tcp通讯

简单的tcp通讯例子。

 

server端

 

/* tcp_server.c */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>

#define MYPORT 8000

int main()
{
    int server_fd, client_fd;
    struct sockaddr_in my_addr, client_addr;
    server_fd = socket(AF_INET, SOCK_STREAM, 0);

    my_addr.sin_family = AF_INET; /* 主机字节序 */
    my_addr.sin_port = htons(MYPORT); /* short, 网络字节序 */

    my_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

    bzero(&(my_addr.sin_zero), 8); /* zero the rest of the struct */

    bind(server_fd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr));

    listen(server_fd, 10);

    while (1) {

        char buf[20];
        printf("server is waiting\n");

        int client_len = sizeof(struct sockaddr);

        client_fd = accept(server_fd, (struct sockaddr*)&client_addr, &client_len);

        printf("accepted\n");

        int n = recv(client_fd, buf, 20, 0);

        printf("received from client %s\n", buf);

        for (int i=0; i<n; i++) {
            if (buf[i]>=97 && buf[i]<=122) {
                buf[i] -= 32;
            }
        }

        send(client_fd, buf, 20, 0);

        close(client_fd);
    }

    close(server_fd);

    return 0;
}

 

client端

 

/* tcp_client.c */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>

int main()
{
        int client_fd;
        struct sockaddr_in server_addr;

        server_addr.sin_family = AF_INET;
        server_addr.sin_port = htons(8000);
        server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
        bzero(&(server_addr.sin_zero), 8);

        client_fd = socket(AF_INET, SOCK_STREAM, 0);

        connect(client_fd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr));

        send(client_fd, "hello\0", 6, 0);

        char buf[20];
        bzero(buf, 20);

        recv(client_fd, buf, sizeof(buf), 0);

        printf("recv %s\n", buf);

        close(client_fd);

        return 0;
}