/*

 * 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.

 */

#include "uv.h"

#include "uv-common.h"

#include <stdio.h>

#include <string.h>

#include <stdint.h>

#define UV__INET_ADDRSTRLEN         16

#define UV__INET6_ADDRSTRLEN        46

static int inet_ntop4(const unsigned char *src, char *dst, size_t size);

static int inet_ntop6(const unsigned char *src, char *dst, size_t size);

static int inet_pton4(const char *src, unsigned char *dst);

static int inet_pton6(const char *src, unsigned char *dst);

int uv_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:

    return UV_EAFNOSUPPORT;

  }

  /* NOTREACHED */

}

static int inet_ntop4(const unsigned char *src, char *dst, size_t size) {

  static const char fmt[] = "%u.%u.%u.%u";

  char tmp[UV__INET_ADDRSTRLEN];

  int l;

  l = snprintf(tmp, sizeof(tmp), fmt, src[0], src[1], src[2], src[3]);

  if (l <= 0 || (size_t) l >= size) {

    return UV_ENOSPC;

  }

  uv__strscpy(dst, tmp, size);

  return 0;

}

static int inet_ntop6(const unsigned 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[UV__INET6_ADDRSTRLEN], *tp;

  struct { int base, len; } best, cur;

  unsigned int words[sizeof(struct in6_addr) / sizeof(uint16_t)];

  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 < (int) sizeof(struct in6_addr); i++)

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

  best.base = -1;

  best.len = 0;

  cur.base = -1;

  cur.len = 0;

  for (i = 0; i < (int) ARRAY_SIZE(words); 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 < (int) ARRAY_SIZE(words); 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 err = inet_ntop4(src+12, tp, sizeof tmp - (tp - tmp));

      if (err)

        return err;

      tp += strlen(tp);

      break;

    }

    tp += snprintf(tp, sizeof tmp - (tp - tmp), "%x", words[i]);

  }

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

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

    *tp++ = ':';

  *tp++ = '\0';

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

    return UV_ENOSPC;

  uv__strscpy(dst, tmp, size);

  return 0;

}

int uv_inet_pton(int af, const char* src, void* dst) {

  if (src == NULL || dst == NULL)

    return UV_EINVAL;

  switch (af) {

  case AF_INET:

    return (inet_pton4(src, dst));

  case AF_INET6: {

    int len;

    char tmp[UV__INET6_ADDRSTRLEN], *s, *p;

    s = (char*) src;

    p = strchr(src, '%');

    if (p != NULL) {

      s = tmp;

      len = p - src;

      if (len > UV__INET6_ADDRSTRLEN-1)

        return UV_EINVAL;

      memcpy(s, src, len);

      s[len] = '\0';

    }

    return inet_pton6(s, dst);

  }

  default:

    return UV_EAFNOSUPPORT;

  }

  /* NOTREACHED */

}

static int inet_pton4(const char *src, unsigned char *dst) {

  static const char digits[] = "0123456789";

  int saw_digit, octets, ch;

  unsigned char tmp[sizeof(struct in_addr)], *tp;

  saw_digit = 0;

  octets = 0;

  *(tp = tmp) = 0;

  while ((ch = *src++) != '\0') {

    const char *pch;

    if ((pch = strchr(digits, ch)) != NULL) {

      unsigned int nw = *tp * 10 + (pch - digits);

      if (saw_digit && *tp == 0)

        return UV_EINVAL;

      if (nw > 255)

        return UV_EINVAL;

      *tp = nw;

      if (!saw_digit) {

        if (++octets > 4)

          return UV_EINVAL;

        saw_digit = 1;

      }

    } else if (ch == '.' && saw_digit) {

      if (octets == 4)

        return UV_EINVAL;

      *++tp = 0;

      saw_digit = 0;

    } else

      return UV_EINVAL;

  }

  if (octets < 4)

    return UV_EINVAL;

  memcpy(dst, tmp, sizeof(struct in_addr));

  return 0;

}

static int inet_pton6(const char *src, unsigned char *dst) {

  static const char xdigits_l[] = "0123456789abcdef",

                    xdigits_u[] = "0123456789ABCDEF";

  unsigned char tmp[sizeof(struct in6_addr)], *tp, *endp, *colonp;

  const char *xdigits, *curtok;

  int ch, seen_xdigits;

  unsigned int val;

  memset((tp = tmp), '\0', sizeof tmp);

  endp = tp + sizeof tmp;

  colonp = NULL;

  /* Leading :: requires some special handling. */

  if (*src == ':')

    if (*++src != ':')

      return UV_EINVAL;

  curtok = src;

  seen_xdigits = 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 (++seen_xdigits > 4)

        return UV_EINVAL;

      continue;

    }

    if (ch == ':') {

      curtok = src;

      if (!seen_xdigits) {

        if (colonp)

          return UV_EINVAL;

        colonp = tp;

        continue;

      } else if (*src == '\0') {

        return UV_EINVAL;

      }

      if (tp + sizeof(uint16_t) > endp)

        return UV_EINVAL;

      *tp++ = (unsigned char) (val >> 8) & 0xff;

      *tp++ = (unsigned char) val & 0xff;

      seen_xdigits = 0;

      val = 0;

      continue;

    }

    if (ch == '.' && ((tp + sizeof(struct in_addr)) <= endp)) {

      int err = inet_pton4(curtok, tp);

      if (err == 0) {

        tp += sizeof(struct in_addr);

        seen_xdigits = 0;

        break;  /*%< '\\0' was seen by inet_pton4(). */

      }

    }

    return UV_EINVAL;

  }

  if (seen_xdigits) {

    if (tp + sizeof(uint16_t) > endp)

      return UV_EINVAL;

    *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;

    if (tp == endp)

      return UV_EINVAL;

    for (i = 1; i <= n; i++) {

      endp[- i] = colonp[n - i];

      colonp[n - i] = 0;

    }

    tp = endp;

  }

  if (tp != endp)

    return UV_EINVAL;

  memcpy(dst, tmp, sizeof tmp);

  return 0;

}