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inet_pton.c

/* Copyright (c) 1996 by Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/* Modified by Fyodor (fyodor@insecure.org) for inclusion in the Nmap 
 * Security Scanner.
 *
 * $Id: inet_pton.c 1938 2003-08-16 03:29:26Z fyodor $
 */

#include "nbase.h"

#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#if HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#if HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#endif
#if HAVE_ERRNO_H
#include <errno.h>
#endif

#ifndef IN6ADDRSZ
#define IN6ADDRSZ   16
#endif

#ifndef INT16SZ
#define INT16SZ 2
#endif

#ifndef INADDRSZ
#define INADDRSZ    4
#endif

#if !defined(EAFNOSUPPORT) && defined(WSAEAFNOSUPPORT)
#define EAFNOSUPPORT WSAEAFNOSUPPORT
#endif

/*
 * WARNING: Don't even consider trying to compile this on a system where
 * sizeof(int) < 4.  sizeof(int) > 4 is fine; all the world's not a VAX.
 */

static int  inet_pton4 (const char *src, unsigned char *dst);
#if HAVE_IPV6
static int  inet_pton6 (const char *src, unsigned char *dst);
#endif

/* int
 * inet_pton(af, src, dst)
 *    convert from presentation format (which usually means ASCII printable)
 *    to network format (which is usually some kind of binary format).
 * return:
 *    1 if the address was valid for the specified address family
 *    0 if the address wasn't valid (`dst' is untouched in this case)
 *    -1 if some other error occurred (`dst' is untouched in this case, too)
 * author:
 *    Paul Vixie, 1996.
 */
int
inet_pton(int af, const char *src, void *dst)
{
      switch (af) {
      case AF_INET:
            return (inet_pton4(src, (unsigned char *) dst));
#if HAVE_IPV6
      case AF_INET6:
            return (inet_pton6(src, (unsigned char *) dst));
#endif
      default:
#ifndef WIN32
            errno = EAFNOSUPPORT;
#endif
            return (-1);
      }
      /* NOTREACHED */
}

/* int
 * inet_pton4(src, dst)
 *    like inet_aton() but without all the hexadecimal and shorthand.
 * return:
 *    1 if `src' is a valid dotted quad, else 0.
 * notice:
 *    does not touch `dst' unless it's returning 1.
 * author:
 *    Paul Vixie, 1996.
 */
static int
inet_pton4(const char *src, unsigned char *dst)
{
      static const char digits[] = "0123456789";
      int saw_digit, octets, ch;
      unsigned char tmp[INADDRSZ], *tp;

      saw_digit = 0;
      octets = 0;
      *(tp = tmp) = 0;
      while ((ch = *src++) != '\0') {
            const char *pch;

            if ((pch = strchr(digits, ch)) != NULL) {
                  unsigned int newval = (unsigned int) (*tp * 10 + (pch - digits));

                  if (newval > 255)
                        return (0);
                  *tp = newval;
                  if (! saw_digit) {
                        if (++octets > 4)
                              return (0);
                        saw_digit = 1;
                  }
            } else if (ch == '.' && saw_digit) {
                  if (octets == 4)
                        return (0);
                  *++tp = 0;
                  saw_digit = 0;
            } else
                  return (0);
      }
      if (octets < 4)
            return (0);

      memcpy(dst, tmp, INADDRSZ);
      return (1);
}

#if HAVE_IPV6
/* int
 * inet_pton6(src, dst)
 *    convert presentation level address to network order binary form.
 * return:
 *    1 if `src' is a valid [RFC1884 2.2] address, else 0.
 * notice:
 *    (1) does not touch `dst' unless it's returning 1.
 *    (2) :: in a full address is silently ignored.
 * credit:
 *    inspired by Mark Andrews.
 * author:
 *    Paul Vixie, 1996.
 */
static int
inet_pton6(const char *src, unsigned char *dst)
{
      static const char xdigits_l[] = "0123456789abcdef",
                    xdigits_u[] = "0123456789ABCDEF";
      unsigned char tmp[IN6ADDRSZ], *tp, *endp, *colonp;
      const char *xdigits, *curtok;
      int ch, saw_xdigit;
      unsigned int val;

      memset((tp = tmp), '\0', IN6ADDRSZ);
      endp = tp + IN6ADDRSZ;
      colonp = NULL;
      /* Leading :: requires some special handling. */
      if (*src == ':')
            if (*++src != ':')
                  return (0);
      curtok = src;
      saw_xdigit = 0;
      val = 0;
      while ((ch = *src++) != '\0') {
            const char *pch;

            if ((pch = strchr((xdigits = xdigits_l), ch)) == NULL)
                  pch = strchr((xdigits = xdigits_u), ch);
            if (pch != NULL) {
                  val <<= 4;
                  val |= (pch - xdigits);
                  if (val > 0xffff)
                        return (0);
                  saw_xdigit = 1;
                  continue;
            }
            if (ch == ':') {
                  curtok = src;
                  if (!saw_xdigit) {
                        if (colonp)
                              return (0);
                        colonp = tp;
                        continue;
                  }
                  if (tp + INT16SZ > endp)
                        return (0);
                  *tp++ = (unsigned char) (val >> 8) & 0xff;
                  *tp++ = (unsigned char) val & 0xff;
                  saw_xdigit = 0;
                  val = 0;
                  continue;
            }
            if (ch == '.' && ((tp + INADDRSZ) <= endp) &&
                inet_pton4(curtok, tp) > 0) {
                  tp += INADDRSZ;
                  saw_xdigit = 0;
                  break;      /* '\0' was seen by inet_pton4(). */
            }
            return (0);
      }
      if (saw_xdigit) {
            if (tp + INT16SZ > endp)
                  return (0);
            *tp++ = (unsigned char) (val >> 8) & 0xff;
            *tp++ = (unsigned char) val & 0xff;
      }
      if (colonp != NULL) {
            /*
             * Since some memmove()'s erroneously fail to handle
             * overlapping regions, we'll do the shift by hand.
             */
            const int n = tp - colonp;
            int i;

            for (i = 1; i <= n; i++) {
                  endp[- i] = colonp[n - i];
                  colonp[n - i] = 0;
            }
            tp = endp;
      }
      if (tp != endp)
            return (0);
      memcpy(dst, tmp, IN6ADDRSZ);
      return (1);
}
#endif

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