problems with TCP client

devit · 05-29-2004, 07:43 PM

I have a Slackware 9.1 box and I tried to make a simple TCP server and his client. The server has to receive a string and return it to the client. The server works well but not the client.

Hoping this will help, I posted the code of the client:

Code:

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>
#include <string.h>

extern int errno;

int port;

int main (int argc, char *argv[])
{
  int sd;
  struct sockaddr_in server;
  char buffer[100];

  if (argc != 3) {
    printf ("Sintaxa: %s <adresa_server> <port>\n", argv[0]);
    return -1;
  }

  port = atoi (argv[2]);

  if ((sd = socket (AF_INET, SOCK_STREAM, 0)) == -1) {
    perror ("Eroare la socket().\n");
    return errno;
  }

  server.sin_family = AF_INET;
  server.sin_addr.s_addr = htonl (inet_addr(argv[1]));
  server.sin_port = htons (port);

  if (connect (sd, (struct sockaddr *) &server, sizeof (struct sockaddr)) == -1) {
    perror ("Eroare la connect().\n");
    return errno;
  }

  bzero (buffer, 100);
  printf ("Introduceti mesajul: ");
  fflush (stdout);
  read (0, buffer, 100);

  if (write (sd, buffer, 100) <= 0) {
    perror ("Eroare la write() spre server.\n");
    return errno;
  }

  if (read (sd, buffer, 100) < 0) {
    perror ("Eroare la read() de la server.\n");
    return errno;
  }

  printf ("Mesajul primit este: \"%s\".\n", buffer);

  close (sd);
}

When I start the client I receive this error:

Code:

bash-2.05b$ ./client-tcp 127.0.0.1 8081
Eroare la connect().
: Network is unreachable
bash-2.05b$

I tried ping 127.0.0.1 and there is no problem there. Could you help me!

Thanks!

Hko · 05-29-2004, 08:08 PM

Just guessing, but is it possible that you have 127.0.0.1 firewalled (for port 8081)?

itsme86 · 05-29-2004, 10:35 PM

Try setting server up like this:

Code:

    server.sin_family = PF_INET;
    server.sin_port = htons(port);
    inet_aton(argv[1], &server.sin_addr);

The 3rd argument to connect() should also be sizeof(struct sockaddr_in) instead of sizeof(struct sockaddr).

Also, bzero() is deprecated. Best to use memset(buffer, 0, 100);