c__netclient/netclient.c

/**
 * Simple TCP connection check
 * (c) 1993-2008 OSI 
 *
 * Proprietary unpublished code
 *
 * WARNING: contains various assumptions regarding the use of IPv4
 * This is NOT production-quality code, just a quick debug test
 */
#include "sys/socket.h"
#include "netinet/in.h"
#include "arpa/inet.h"
#include "netdb.h"
#include "stdio.h"

//	HOST	"profile.microscopy-analysis.com"
//	PORT	8080
//
#define MAX_BUF	100

/**
 * Dump client socket info for IPv4
 */
int showServ(struct sockaddr_in *sn)
  {
  printf("IP Dump\n");
  printf("  Family [%d]\n", sn->sin_family);
  printf("  Host [%s]\n",	inet_ntoa(sn->sin_addr));
  printf("  Port [%d]\n", ntohs(sn->sin_port));
  }

/**
 * Return the last IP in the resolution list for host name
 */
char *getServIp(char *name)
  {
  struct hostent *he = gethostbyname(name);
  int	i;
  static	char addr[MAX_BUF];
  struct in_addr	*pin;

  if (he == NULL)
    return NULL;
  
  printf("Host check:\n  Name %s\n  Canonical name %s\n  Addr len %d\n  Family %d\n",
  	name, he->h_name, he->h_length, he->h_addrtype);

  i = 0;
  while (he->h_addr_list[i] != NULL)
    {
	pin = (struct in_addr *) he->h_addr_list[i];
	strcpy(addr, inet_ntoa(*pin));
	printf("  IP %s\n", addr);
	i++;
	}
  return addr;
  }

/**
 * Main function
 */
int main (int argc, char **argv)
  {
  int					sockd;
  int					count;
  struct sockaddr_in	serv_name;
  char					buf[MAX_BUF];
  int					status;
  char					*ip;

  if (argc != 3)
    {
	fprintf(stderr, "Syntax, %s <host> <port>\n", argv[0]);
	exit(1);
	}
  strcpy(buf, argv[1]);
  ip = getServIp(buf); // warning: static result, overwritten by each call

  sockd = socket(AF_INET, SOCK_STREAM, 0);
  if (sockd == -1)
    {
	perror("Socket creation");
	exit(2);
	}

  serv_name.sin_family = AF_INET;
  /* fprintf(stderr, "Inet_aton on %s returns %d\n", */ ip, inet_aton(ip, &serv_name.sin_addr); 
  serv_name.sin_port = htons(atoi(argv[2]));

  showServ(&serv_name);
  fprintf(stderr, "Trying to connect to %s:%d\n", argv[1], atoi(argv[2]));
  status = connect(sockd, (struct sockaddr *) &serv_name, sizeof(serv_name));
  if (status == -1)
    {
	perror("Connection error");
	exit(3);
	}
  fputs("Connection successful, closing\n", stderr);
  shutdown(sockd, 1);
  close(sockd);
  return 0;
  }