네트워크 프로그래밍 과제

서버

#include <time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/uio.h>
#define SA struct sockaddr
#define MAXLINE 4096
#define bzero(ptr, n) memset(ptr, 0, n)
#define LISTENQ 1024
int main(int argc, char **argv){
    int listenfd, connfd;
    struct sockaddr_in servaddr;
    char buff[MAXLINE];
    time_t ticks;

    listenfd = socket(AF_INET, SOCK_STREAM, 0);

    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr=htonl(INADDR_ANY);
    servaddr.sin_port = htons(40000); /*daytime server*/

    bind(listenfd, (SA *) &servaddr, sizeof(servaddr));
    listen(listenfd, LISTENQ);

    for( ; ; ){
       connfd = accept(listenfd, (SA *) NULL, NULL);

       ticks = time(NULL);
       snprintf(buff, sizeof(buff), "%.24s\r\n", ctime(&ticks));
       write(connfd, buff, strlen(buff));

        close(connfd);
    }
}

 

 

클라이언트

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <time.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <syslog.h>
#include <netinet/in.h>
#include <sys/uio.h>
#include <unistd.h>
#define bzero(ptr, n) memset (ptr, 0, n)
#define MAXLINE 4096
#define SA struct sockaddr

int daemon_proc;

static void err_doit(int errnoflag, int level, const char *fmt, va_list ap){
    int errno_save, n;
    char buf[MAXLINE + 1];
    errno_save =errno;
#ifdef HAVE_VSNPRINTF
   vsnprintf(buf, MAXLINE, fmt, ap);
#else
    vsprintf(buf, fmt, ap);
#endif
    n = strlen(buf);
    if(errnoflag)
        snprintf(buf + n, MAXLINE - n, ": %s", strerror(errno_save));
    strcat(buf, "\n");

   if(daemon_proc){
        syslog(level, buf);
   }else{
       fflush(stdout);
        fputs(buf, stderr);
        fflush(stderr);
    }
    return;
}


void err_sys(const char *fmt, ...){
    va_list ap;
   va_start(ap,fmt);
    err_doit(1, LOG_ERR, fmt, ap);
    va_end(ap);
    exit(1);
}

void err_quit(const char *fmt, ...)
{   va_list ap;

    va_start(ap,fmt);
    err_doit(0, LOG_ERR, fmt, ap);

   va_end(ap);
    exit(1);
}

int main(int argc, char **argv){
    int sockfd, n;
    char recvline[MAXLINE + 1];
    struct sockaddr_in servaddr;

    if(argc != 2)
       err_quit("usage : a.out <IPaddress>");
    if( (sockfd = socket( AF_INET , SOCK_STREAM,0 )) < 0)
       err_sys("socket error");

    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port= htons(40000);
    if(inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0)
        err_quit("inet_pton error for %s", argv[1]);
    if(connect(sockfd, (SA *) &servaddr, sizeof(servaddr)) < 0)
        err_sys("connect error");

    while( (n = read(sockfd, recvline, MAXLINE)) > 0){
        recvline[n] = 0;
        if( fputs(recvline, stdout) == EOF)
            err_sys("fputs error");
    }
    if(n<0)
        err_sys("read error");

    exit(0);
}