/*

 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")

 * Copyright (c) 1996,1999 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 ISC DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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.

 *

 *    src/port/inet_net_ntop.c

 */

#if defined(LIBC_SCCS) && !defined(lint)

static const char rcsid[] = "Id: inet_net_ntop.c,v 1.1.2.2 2004/03/09 09:17:27 marka Exp $";

#endif

#ifndef FRONTEND

#include "postgres.h"

#else

#include "postgres_fe.h"

#endif

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#ifndef FRONTEND

#include "utils/inet.h"

#else

/*

 * In a frontend build, we can't include inet.h, but we still need to have

 * sensible definitions of these two constants.  Note that pg_inet_net_ntop()

 * assumes that PGSQL_AF_INET is equal to AF_INET.

 */

#define PGSQL_AF_INET (AF_INET + 0)

#define PGSQL_AF_INET6  (AF_INET + 1)

#endif

#define NS_IN6ADDRSZ 16

#define NS_INT16SZ 2

#ifdef SPRINTF_CHAR

#define SPRINTF(x) strlen(sprintf/**/x)

#else

#define SPRINTF(x) ((size_t)sprintf x)

#endif

static char *inet_net_ntop_ipv4(const u_char *src, int bits,

                char *dst, size_t size);

static char *inet_net_ntop_ipv6(const u_char *src, int bits,

                char *dst, size_t size);

/*

 * char *

 * pg_inet_net_ntop(af, src, bits, dst, size)

 *  convert host/network address from network to presentation format.

 *  "src"'s size is determined from its "af".

 * return:

 *  pointer to dst, or NULL if an error occurred (check errno).

 * note:

 *  192.5.5.1/28 has a nonzero host part, which means it isn't a network

 *  as called for by pg_inet_net_pton() but it can be a host address with

 *  an included netmask.

 * author:

 *  Paul Vixie (ISC), October 1998

 */

char *

pg_inet_net_ntop(int af, const void *src, int bits, char *dst, size_t size)

{

  /*

   * We need to cover both the address family constants used by the PG inet

   * type (PGSQL_AF_INET and PGSQL_AF_INET6) and those used by the system

   * libraries (AF_INET and AF_INET6).  We can safely assume PGSQL_AF_INET

   * == AF_INET, but the INET6 constants are very likely to be different.

   */

  switch (af)

  {

    case PGSQL_AF_INET:

      return (inet_net_ntop_ipv4(src, bits, dst, size));

    case PGSQL_AF_INET6:

#if AF_INET6 != PGSQL_AF_INET6

    case AF_INET6:

#endif

      return (inet_net_ntop_ipv6(src, bits, dst, size));

    default:

      errno = EAFNOSUPPORT;

      return (NULL);

  }

}

/*

 * static char *

 * inet_net_ntop_ipv4(src, bits, dst, size)

 *  convert IPv4 network address from network to presentation format.

 *  "src"'s size is determined from its "af".

 * return:

 *  pointer to dst, or NULL if an error occurred (check errno).

 * note:

 *  network byte order assumed.  this means 192.5.5.240/28 has

 *  0b11110000 in its fourth octet.

 * author:

 *  Paul Vixie (ISC), October 1998

 */

static char *

inet_net_ntop_ipv4(const u_char *src, int bits, char *dst, size_t size)

{

  char     *odst = dst;

  char     *t;

  int     len = 4;

  int     b;

  if (bits < 0 || bits > 32)

  {

    errno = EINVAL;

    return (NULL);

  }

  /* Always format all four octets, regardless of mask length. */

  for (b = len; b > 0; b--)

  {

    if (size <= sizeof ".255")

      goto emsgsize;

    t = dst;

    if (dst != odst)

      *dst++ = '.';

    dst += SPRINTF((dst, "%u", *src++));

    size -= (size_t) (dst - t);

  }

  /* don't print masklen if 32 bits */

  if (bits != 32)

  {

    if (size <= sizeof "/32")

      goto emsgsize;

    dst += SPRINTF((dst, "/%u", bits));

  }

  return (odst);

emsgsize:

  errno = EMSGSIZE;

  return (NULL);

}

static int

decoct(const u_char *src, int bytes, char *dst, size_t size)

{

  char     *odst = dst;

  char     *t;

  int     b;

  for (b = 1; b <= bytes; b++)

  {

    if (size <= sizeof "255.")

      return (0);

    t = dst;

    dst += SPRINTF((dst, "%u", *src++));

    if (b != bytes)

    {

      *dst++ = '.';

      *dst = '\0';

    }

    size -= (size_t) (dst - t);

  }

  return (dst - odst);

}

static char *

inet_net_ntop_ipv6(const u_char *src, int bits, 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:255.255.255.255/128"];

  char     *tp;

  struct

  {

    int     base,

          len;

  }     best, cur;

  u_int   words[NS_IN6ADDRSZ / NS_INT16SZ];

  int     i;

  if ((bits < -1) || (bits > 128))

  {

    errno = EINVAL;

    return (NULL);

  }

  /*

   * 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 < NS_IN6ADDRSZ; i++)

    words[i / 2] |= (src[i] << ((1 - (i % 2)) << 3));

  best.base = -1;

  cur.base = -1;

  best.len = 0;

  cur.len = 0;

  for (i = 0; i < (NS_IN6ADDRSZ / NS_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)

  {

    if (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 < (NS_IN6ADDRSZ / NS_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 == 7 && words[7] != 0x0001) ||

                     (best.len == 5 && words[5] == 0xffff)))

    {

      int     n;

      n = decoct(src + 12, 4, tp, sizeof tmp - (tp - tmp));

      if (n == 0)

      {

        errno = EMSGSIZE;

        return (NULL);

      }

      tp += strlen(tp);

      break;

    }

    tp += SPRINTF((tp, "%x", words[i]));

  }

  /* Was it a trailing run of 0x00's? */

  if (best.base != -1 && (best.base + best.len) ==

    (NS_IN6ADDRSZ / NS_INT16SZ))

    *tp++ = ':';

  *tp = '\0';

  if (bits != -1 && bits != 128)

    tp += SPRINTF((tp, "/%u", bits));

  /*

   * Check for overflow, copy, and we're done.

   */

  if ((size_t) (tp - tmp) > size)

  {

    errno = EMSGSIZE;

    return (NULL);

  }

  strcpy(dst, tmp);

  return (dst);

}