presaddr.c

开放源码的编译器open watcom 1.6.0版的源代码

/*
 * 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.
 */

#include "socket.h"

#if defined(USE_BSD_FUNC)

static const char *inet_ntop4 (const u_char *src, char *dst, size_t size);
static const char *inet_ntop6 (const u_char *src, char *dst, size_t size);
static int         inet_pton4 (const char *src, u_char *dst);
static int         inet_pton6 (const char *src, u_char *dst);

/*
 * convert a network format address to presentation format.
 * return:
 *  pointer to presentation format address (`dst'), or NULL (see errno).
 * author:
 *  Paul Vixie, 1996.
 */
const char *inet_ntop (int af, const void *src, char *dst, size_t size)
{
  switch (af)
  {
    case AF_INET:
         return inet_ntop4(src, dst, size);
    case AF_INET6:
         return inet_ntop6(src, dst, size);
    default:
         SOCK_ERR (EAFNOSUPPORT);
         return (NULL);
  }
}


/*
 * 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,dst));
    case AF_INET6:
         return (inet_pton6(src,dst));
    default:
         SOCK_ERR (EAFNOSUPPORT);
         return (-1);
  }
}


/*
 * format an IPv4 address, more or less like inet_ntoa()
 * return:
 *  `dst' (as a const)
 * notes:
 *  (1) uses no statics
 *  (2) takes a u_char* not an in_addr as input
 * author:
 *  Paul Vixie, 1996.
 */
static const char *inet_ntop4 (const u_char *src, char *dst, size_t size)
{
  char tmp [sizeof("255.255.255.255")];

  if (sprintf(tmp,"%u.%u.%u.%u",src[0],src[1],src[2],src[3]) > size)
  {
    SOCK_ERR (ENOSPC);
    return (NULL);
  }
  strcpy (dst, tmp);
  return (dst);
}

/*
 * convert IPv6 binary address into presentation (printable) format
 * author:
 *  Paul Vixie, 1996.
 */
static const char *inet_ntop6 (const u_char *src, char *dst, size_t size)
{
  /*
   * Note that int32_t and int16_t need only be "at least" large enough
   * to contain a value of the specified size.  On some systems, like
   * Crays, there is no such thing as an integer variable with 16 bits.
   * Keep this in mind if you think this function should have been coded
   * to use pointer overlays.  All the world's not a VAX.
   */
  char tmp[sizeof "ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255"], *tp;
  struct {
    long base;
    long len;
  } best, cur;
  u_long words[IN6ADDRSZ / INT16SZ];
  int    i;

  /*
   * Preprocess:
   *  Copy the input (bytewise) array into a wordwise array.
   *  Find the longest run of 0x00's in src[] for :: shorthanding.
   */
  memset (words,0,sizeof(words));
  for (i = 0; i < IN6ADDRSZ; i++)
      words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));

  best.base = -1;
  cur.base  = -1;
  for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
  {
    if (words[i] == 0)
    {
      if (cur.base == -1)
           cur.base = i, cur.len = 1;
      else cur.len++;
    }
    else if (cur.base != -1)
    {
      if (best.base == -1 || cur.len > best.len)
         best = cur;
      cur.base = -1;
    }

  }
  if ((cur.base != -1) && (best.base == -1 || cur.len > best.len))
     best = cur;

  if (best.base != -1 && best.len < 2)
     best.base = -1;

  /*
   * Format the result.
   */
  tp = tmp;
  for (i = 0; i < (IN6ADDRSZ / INT16SZ); i++)
  {
    /* Are we inside the best run of 0x00's? */
    if (best.base != -1 && i >= best.base && i < (best.base + best.len))
    {
      if (i == best.base)
         *tp++ = ':';
      continue;
    }
    /* Are we following an initial run of 0x00s or any real hex? */
    if (i != 0)
       *tp++ = ':';
    /* Is this address an encapsulated IPv4? */
    if (i == 6 && best.base == 0 &&
        (best.len == 6 || (best.len == 5 && words[5] == 0xffff)))
    {
      if (!inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp)))
         return (NULL);
      tp += strlen(tp);
      break;
    }
    tp += sprintf (tp, "%lx", words[i]);
  }

  /* Was it a trailing run of 0x00's? */
  if (best.base != -1 && (best.base + best.len) == (IN6ADDRSZ / INT16SZ))
     *tp++ = ':';
  *tp++ = '\0';

  /*
   * Check for overflow, copy, and we're done.
   */
  if ((size_t)(tp - tmp) > size)
  {
    SOCK_ERR (ENOSPC);
    return (NULL);
  }
  strcpy (dst, tmp);
  return (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, u_char *dst)
{
  static const char digits[] = "0123456789";
  int    saw_digit, octets, ch;
  u_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)
    {
      u_int new = *tp * 10 + (pch - digits);

      if (new > 255)
         return (0);
      *tp = new;
      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);
}

/*
 * 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, u_char *dst)
{
  u_char tmp[IN6ADDRSZ], *endp, *colonp;
  u_char *tp = tmp;
  const  char *xdigits, *curtok;
  int    ch, saw_xdigit;
  u_int  val;

  memset (tp,0,IN6ADDRSZ);
  endp = tp + IN6ADDRSZ;
  colonp = NULL;

  /* Leading :: requires some special handling.
   */
  if (*src == ':' && *++src != ':')
     return (0);

  curtok = src;
  saw_xdigit = 0;
  val = 0;

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

    if ((pch = strchr((xdigits = hex_chars), ch)) == NULL)
       pch = strchr ((xdigits = hex_CHARS), ch);
    if (pch)
    {
      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++ = (u_char) (val >> 8) & 0xff;
      *tp++ = (u_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++ = (u_char) (val >> 8) & 0xff;
    *tp++ = (u_char) val & 0xff;
  }
  if (colonp)
  {
    /*
     * 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  /* USE_BSD_FUNC */