tcpcli2.c

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>

#define SRVPORT 49152

main()
{
    int s, cnt;
    char lbuf[80], msg[80];
    struct sockaddr_in skt;
    struct in_addr ipaddr;

    if ((s = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        perror("socket");
        exit(1);
    }
    printf("server IP address: ");
    fgets(lbuf, sizeof lbuf, stdin);

    if (inet_aton(lbuf, &ipaddr) < 0) {
        perror("inet_aton");
        exit(1);
    }

    memset(&skt, 0, sizeof skt);
    skt.sin_family = AF_INET;
    skt.sin_port = htons(SRVPORT);
    skt.sin_addr.s_addr = htonl(ipaddr.s_addr);

    if (connect(s, (struct sockaddr *)&skt, sizeof skt) < 0) {
        perror("connect");
        exit(1);
    }

    for (;;) {
        printf("message to be sent: ");
        if (fgets(msg, sizeof msg, stdin) == NULL) {
            break;
        }
        msg[strlen(msg) - 1] = '\0';

        if ((cnt = send(s, msg, sizeof msg, 0)) < 0) {
            perror("send");
            exit(1);
        }
        printf("%d bytes sent\n", cnt);

        if ((cnt = recv(s, msg, sizeof msg, 0)) < 0) {
            perror("recv");
            exit(1);
        }
        msg[cnt] = '\0';
        printf("%d bytes recved: IP %s, port %d, msg %s\n",
               cnt, inet_ntoa(skt.sin_addr),
               ntohs(skt.sin_port), msg);
    }
    printf("EOF received from keyboard\n");
    close(s);
}