
/***************************************************************************
 * nbase_misc.c -- Some small miscelaneous utility/compatability           *
 * functions.                                                              *
 *                                                                         *
 ***********************IMPORTANT NMAP LICENSE TERMS************************
 *                                                                         *
 * The Nmap Security Scanner is (C) 1995-2003 Insecure.Com LLC. This       *
 * program is free software; you may redistribute and/or modify it under   *
 * the terms of the GNU General Public License as published by the Free    *
 * Software Foundation; Version 2.  This guarantees your right to use,     *
 * modify, and redistribute this software under certain conditions.  If    *
 * you wish to embed Nmap technology into proprietary software, we may be  *
 * willing to sell alternative licenses (contact sales@insecure.com).      *
 * Many security scanner vendors already license Nmap technology such as   *
 * our remote OS fingerprinting database and code.                         *
 *                                                                         *
 * Note that the GPL places important restrictions on "derived works", yet *
 * it does not provide a detailed definition of that term.  To avoid       *
 * misunderstandings, we consider an application to constitute a           *
 * "derivative work" for the purpose of this license if it does any of the *
 * following:                                                              *
 * o Integrates source code from Nmap                                      *
 * o Reads or includes Nmap copyrighted data files, such as                *
 *   nmap-os-fingerprints or nmap-service-probes.                          *
 * o Executes Nmap                                                         *
 * o Integrates/includes/aggregates Nmap into an executable installer      *
 * o Links to a library or executes a program that does any of the above   *
 *                                                                         *
 * The term "Nmap" should be taken to also include any portions or derived *
 * works of Nmap.  This list is not exclusive, but is just meant to        *
 * clarify our interpretation of derived works with some common examples.  *
 * These restrictions only apply when you actually redistribute Nmap.  For *
 * example, nothing stops you from writing and selling a proprietary       *
 * front-end to Nmap.  Just distribute it by itself, and point people to   *
 * http://www.insecure.org/nmap/ to download Nmap.                         *
 *                                                                         *
 * We don't consider these to be added restrictions on top of the GPL, but *
 * just a clarification of how we interpret "derived works" as it applies  *
 * to our GPL-licensed Nmap product.  This is similar to the way Linus     *
 * Torvalds has announced his interpretation of how "derived works"        *
 * applies to Linux kernel modules.  Our interpretation refers only to     *
 * Nmap - we don't speak for any other GPL products.                       *
 *                                                                         *
 * If you have any questions about the GPL licensing restrictions on using *
 * Nmap in non-GPL works, we would be happy to help.  As mentioned above,  *
 * we also offer alternative license to integrate Nmap into proprietary    *
 * applications and appliances.  These contracts have been sold to many    *
 * security vendors, and generally include a perpetual license as well as  *
 * providing for priority support and updates as well as helping to fund   *
 * the continued development of Nmap technology.  Please email             *
 * sales@insecure.com for further information.                             *
 *                                                                         *
 * If you received these files with a written license agreement or         *
 * contract stating terms other than the (GPL) terms above, then that      *
 * alternative license agreement takes precedence over these comments.     *
 *                                                                         *
 * Source is provided to this software because we believe users have a     *
 * right to know exactly what a program is going to do before they run it. *
 * This also allows you to audit the software for security holes (none     *
 * have been found so far).                                                *
 *                                                                         *
 * Source code also allows you to port Nmap to new platforms, fix bugs,    *
 * and add new features.  You are highly encouraged to send your changes   *
 * to fyodor@insecure.org for possible incorporation into the main         *
 * distribution.  By sending these changes to Fyodor or one the            *
 * Insecure.Org development mailing lists, it is assumed that you are      *
 * offering Fyodor and Insecure.Com LLC the unlimited, non-exclusive right *
 * to reuse, modify, and relicense the code.  Nmap will always be          *
 * available Open Source, but this is important because the inability to   *
 * relicense code has caused devastating problems for other Free Software  *
 * projects (such as KDE and NASM).  We also occasionally relicense the    *
 * code to third parties as discussed above.  If you wish to specify       *
 * special license conditions of your contributions, just say so when you  *
 * send them.                                                              *
 *                                                                         *
 * This program is distributed in the hope that it will be useful, but     *
 * WITHOUT ANY WARRANTY; without even the implied warranty of              *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU       *
 * General Public License for more details at                              *
 * http://www.gnu.org/copyleft/gpl.html .                                  *
 *                                                                         *
 ***************************************************************************/

/* $Id: nbase_misc.c,v 1.9 2003/09/11 02:12:57 fyodor Exp $ */

#ifndef WIN32
#include <errno.h>
extern int errno;
#else
#include <winsock2.h>
#endif

#include <assert.h>

#include "nbase.h"
#include "nbase_ipv6.h"

#ifndef INET6_ADDRSTRLEN
#define INET6_ADDRSTRLEN 46
#endif

/* Returns the UNIX/Windows errno-equivalent.  Note that the Windows
   call is socket/networking specific.  The windows error number
   returned is like WSAMSGSIZE, but nbase.h includes #defines to
   correlate many of the common UNIX errors with their closest Windows
   equivalents.  So you can use EMSGSIZE or EINTR. */
int socket_errno() {
#ifdef WIN32
	return WSAGetLastError();
#else
	return errno;
#endif
}

/* This function is an easier version of inet_ntop because you don't
   need to pass a dest buffer.  Instead, it returns a static buffer that
   you can use until the function is called again (by the same or another
   thread in the process).  If there is a wierd error (like sslen being
   too short) then NULL will be returned. */
const char *inet_ntop_ez(struct sockaddr_storage *ss, size_t sslen) {

  struct sockaddr_in *sin = (struct sockaddr_in *) ss;
  static char str[INET6_ADDRSTRLEN];
#if HAVE_IPV6
  struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) ss;
#endif

  str[0] = '\0';

  if (sin->sin_family == AF_INET) {
    if (sslen < sizeof(struct sockaddr_in))
      return NULL;
    return inet_ntop(AF_INET, &sin->sin_addr, str, sizeof(str));
  } 
#if HAVE_IPV6
  else {
    assert(sin->sin_family == AF_INET6);
    if (sslen < sizeof(struct sockaddr_in6))
      return NULL;
    return inet_ntop(AF_INET6, &sin6->sin6_addr, str, sizeof(str));
  } 
#endif

  return NULL;
}
