02-基本TCP套接字编程

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/isunbin/article/details/84720705

//server.c
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <arpa/inet.h>


#define SERV_PROT 9527

void sys_err(const char *str)
{
    perror(str);
    exit(1);
}

int main()
{
    int lfd = 0, cfd = 0;
    int ret;
    int i;
    char buf[BUFSIZ], client_IP[1024];  //系统定义宏：4096
    struct sockaddr_in serv_addr, clit_addr;
    socklen_t clit_addr_len;

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(SERV_PROT);
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);


    lfd = socket(AF_INET, SOCK_STREAM, 0);
    if (lfd == -1)
        sys_err("socket error");

    bind(lfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr));

    listen(lfd, 20);
    clit_addr_len = sizeof(clit_addr);
    cfd = accept(lfd, (struct sockaddr*)&clit_addr, &clit_addr_len);
    if (cfd == -1)
        sys_err("accept error");
    printf("client ip :%s port: %d\n", inet_ntop(AF_INET, &clit_addr.sin_addr.s_addr, client_IP, sizeof(client_IP)),
        ntohs(clit_addr.sin_port));
    while (1)
    {
        ret = read(cfd, buf, sizeof(buf));
        write(STDOUT_FILENO, buf, ret);

        for (i = 0; i < ret; i++)
            buf[i] = toupper(buf[i]);

        write(cfd, buf, ret);
    }
    close(lfd);
    close(cfd);
    return 0;

}

//client.c
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <arpa/inet.h>


#define SERV_PROT 9527

void sys_err(const char *str)
{
    perror(str);
    exit(1);
}

int main()
{
    int cfd;
    int conter = 10;
    char buf[BUFSIZ];

    struct sockaddr_in serv_addr;

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(SERV_PROT);
    inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr.s_addr);

    cfd = socket(AF_INET, SOCK_STREAM, 0);
    if (cfd == -1)
        sys_err("socket error");
    int ret = connect(cfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
    if (ret != 0)
        sys_err("connect err");

    while (--conter)
    {
        write(cfd, "hello\n", 6);
        ret = read(cfd, buf, sizeof(buf));
        write(STDOUT_FILENO, buf, ret);
        sleep(1);
    }
    close(cfd);
    return 0;
}