src/lib/inet_net_pton.c - third_party/c-ares - Git at Google

 /*
  * Copyright (c) 2012 by Gilles Chehade <gilles@openbsd.org>
  * 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 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.
  *
  * SPDX-License-Identifier: MIT
  */

 #include "ares_private.h"

 #ifdef HAVE_NETINET_IN_H
 #  include <netinet/in.h>
 #endif
 #ifdef HAVE_ARPA_INET_H
 #  include <arpa/inet.h>
 #endif

 #include "ares_nameser.h"

 #include "ares_ipv6.h"
 #include "ares_inet_net_pton.h"

 #ifdef USE_WINSOCK
 #  define SOCKERRNO        ((int)WSAGetLastError())
 #  define SET_SOCKERRNO(x) (WSASetLastError((int)(x)))
 #  undef EMSGSIZE
 #  define EMSGSIZE WSAEMSGSIZE
 #  undef ENOENT
 #  define ENOENT WSA_INVALID_PARAMETER
 #  undef EAFNOSUPPORT
 #  define EAFNOSUPPORT WSAEAFNOSUPPORT
 #else
 #  define SOCKERRNO        (errno)
 #  define SET_SOCKERRNO(x) (errno = (x))
 #endif

 const struct ares_in6_addr ares_in6addr_any = { { { 0, 0, 0, 0, 0, 0, 0, 0, 0,
                                                     0, 0, 0, 0, 0, 0, 0 } } };

 /*
  * static int
  * inet_net_pton_ipv4(src, dst, size)
  *      convert IPv4 network number from presentation to network format.
  *      accepts hex octets, hex strings, decimal octets, and /CIDR.
  *      "size" is in bytes and describes "dst".
  * return:
  *      number of bits, either imputed classfully or specified with /CIDR,
  *      or -1 if some failure occurred (check errno).  ENOENT means it was
  *      not an IPv4 network specification.
  * note:
  *      network byte order assumed.  this means 192.5.5.240/28 has
  *      0b11110000 in its fourth octet.
  * note:
  *      On Windows we store the error in the thread errno, not
  *      in the winsock error code. This is to avoid losing the
  *      actual last winsock error. So use macro ERRNO to fetch the
  *      errno this function sets when returning (-1), not SOCKERRNO.
  * author:
  *      Paul Vixie (ISC), June 1996
  */
 static int ares_inet_net_pton_ipv4(const char *src, unsigned char *dst,
                                    size_t size)
 {
   static const char    xdigits[] = "0123456789abcdef";
   static const char    digits[]  = "0123456789";
   int                  n;
   int                  ch;
   int                  tmp = 0;
   int                  dirty;
   int                  bits;
   const unsigned char *odst = dst;

   ch = *src++;
   if (ch == '0' && (src[0] == 'x' || src[0] == 'X') && ares_isascii(src[1]) &&
       ares_isxdigit(src[1])) {
     /* Hexadecimal: Eat nybble string. */
     if (!size) {
       goto emsgsize;
     }
     dirty = 0;
     src++; /* skip x or X. */
     while ((ch = *src++) != '\0' && ares_isascii(ch) && ares_isxdigit(ch)) {
       if (ares_isupper(ch)) {
         ch = ares_tolower((unsigned char)ch);
       }
       n = (int)(strchr(xdigits, ch) - xdigits);
       if (dirty == 0) {
         tmp = n;
       } else {
         tmp = (tmp << 4) | n;
       }
       if (++dirty == 2) {
         if (!size--) {
           goto emsgsize;
         }
         *dst++ = (unsigned char)tmp;
         dirty  = 0;
       }
     }
     if (dirty) { /* Odd trailing nybble? */
       if (!size--) {
         goto emsgsize;
       }
       *dst++ = (unsigned char)(tmp << 4);
     }
   } else if (ares_isascii(ch) && ares_isdigit(ch)) {
     /* Decimal: eat dotted digit string. */
     for (;;) {
       tmp = 0;
       do {
         n    = (int)(strchr(digits, ch) - digits);
         tmp *= 10;
         tmp += n;
         if (tmp > 255) {
           goto enoent;
         }
       } while ((ch = *src++) != '\0' && ares_isascii(ch) && ares_isdigit(ch));
       if (!size--) {
         goto emsgsize;
       }
       *dst++ = (unsigned char)tmp;
       if (ch == '\0' || ch == '/') {
         break;
       }
       if (ch != '.') {
         goto enoent;
       }
       ch = *src++;
       if (!ares_isascii(ch) || !ares_isdigit(ch)) {
         goto enoent;
       }
     }
   } else {
     goto enoent;
   }

   bits = -1;
   if (ch == '/' && ares_isascii(src[0]) && ares_isdigit(src[0]) && dst > odst) {
     /* CIDR width specifier.  Nothing can follow it. */
     ch   = *src++; /* Skip over the /. */
     bits = 0;
     do {
       n     = (int)(strchr(digits, ch) - digits);
       bits *= 10;
       bits += n;
       if (bits > 32) {
         goto enoent;
       }
     } while ((ch = *src++) != '\0' && ares_isascii(ch) && ares_isdigit(ch));
     if (ch != '\0') {
       goto enoent;
     }
   }

   /* Firey death and destruction unless we prefetched EOS. */
   if (ch != '\0') {
     goto enoent;
   }

   /* If nothing was written to the destination, we found no address. */
   if (dst == odst) {
     goto enoent; /* LCOV_EXCL_LINE: all valid paths above increment dst */
   }
   /* If no CIDR spec was given, infer width from net class. */
   if (bits == -1) {
     if (*odst >= 240) {        /* Class E */
       bits = 32;
     } else if (*odst >= 224) { /* Class D */
       bits = 8;
     } else if (*odst >= 192) { /* Class C */
       bits = 24;
     } else if (*odst >= 128) { /* Class B */
       bits = 16;
     } else {                   /* Class A */
       bits = 8;
     }
     /* If imputed mask is narrower than specified octets, widen. */
     if (bits < ((dst - odst) * 8)) {
       bits = (int)(dst - odst) * 8;
     }
     /*
      * If there are no additional bits specified for a class D
      * address adjust bits to 4.
      */
     if (bits == 8 && *odst == 224) {
       bits = 4;
     }
   }
   /* Extend network to cover the actual mask. */
   while (bits > ((dst - odst) * 8)) {
     if (!size--) {
       goto emsgsize;
     }
     *dst++ = '\0';
   }
   return bits;

 enoent:
   SET_SOCKERRNO(ENOENT);
   return -1;

 emsgsize:
   SET_SOCKERRNO(EMSGSIZE);
   return -1;
 }

 static int getbits(const char *src, size_t *bitsp)
 {
   static const char digits[] = "0123456789";
   size_t            n;
   size_t            val;
   char              ch;

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

     pch = strchr(digits, ch);
     if (pch != NULL) {
       if (n++ != 0 && val == 0) { /* no leading zeros */
         return 0;
       }
       val *= 10;
       val += (size_t)(pch - digits);
       if (val > 128) { /* range */
         return 0;
       }
       continue;
     }
     return 0;
   }
   if (n == 0) {
     return 0;
   }
   *bitsp = val;
   return 1;
 }

 static int ares_inet_pton6(const char *src, unsigned char *dst)
 {
   static const char xdigits_l[] = "0123456789abcdef";
   static const char xdigits_u[] = "0123456789ABCDEF";
   unsigned char     tmp[NS_IN6ADDRSZ];
   unsigned char    *tp;
   unsigned char    *endp;
   unsigned char    *colonp;
   const char       *xdigits;
   const char       *curtok;
   int               ch;
   int               saw_xdigit;
   int               count_xdigit;
   unsigned int      val;

   memset((tp = tmp), '\0', NS_IN6ADDRSZ);
   endp   = tp + NS_IN6ADDRSZ;
   colonp = NULL;
   /* Leading :: requires some special handling. */
   if (*src == ':') {
     if (*++src != ':') {
       goto enoent;
     }
   }
   curtok     = src;
   saw_xdigit = count_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) {
       if (count_xdigit >= 4) {
         goto enoent;
       }
       val <<= 4;
       val  |= (unsigned int)(pch - xdigits);
       if (val > 0xffff) {
         goto enoent;
       }
       saw_xdigit = 1;
       count_xdigit++;
       continue;
     }
     if (ch == ':') {
       curtok = src;
       if (!saw_xdigit) {
         if (colonp) {
           goto enoent;
         }
         colonp = tp;
         continue;
       } else if (*src == '\0') {
         goto enoent;
       }
       if (tp + NS_INT16SZ > endp) {
         goto enoent;
       }
       *tp++        = (unsigned char)(val >> 8) & 0xff;
       *tp++        = (unsigned char)val & 0xff;
       saw_xdigit   = 0;
       count_xdigit = 0;
       val          = 0;
       continue;
     }
     if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
         ares_inet_net_pton_ipv4(curtok, tp, NS_INADDRSZ) > 0) {
       tp         += NS_INADDRSZ;
       saw_xdigit  = 0;
       break; /* '\0' was seen by inet_pton4(). */
     }
     goto enoent;
   }
   if (saw_xdigit) {
     if (tp + NS_INT16SZ > endp) {
       goto enoent;
     }
     *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 = (int)(tp - colonp);
     int       i;

     if (tp == endp) {
       goto enoent;
     }
     for (i = 1; i <= n; i++) {
       endp[-i]      = colonp[n - i];
       colonp[n - i] = 0;
     }
     tp = endp;
   }
   if (tp != endp) {
     goto enoent;
   }

   memcpy(dst, tmp, NS_IN6ADDRSZ);
   return 1;

 enoent:
   SET_SOCKERRNO(ENOENT);
   return -1;
 }

 static int ares_inet_net_pton_ipv6(const char *src, unsigned char *dst,
                                    size_t size)
 {
   struct ares_in6_addr in6;
   int                  ret;
   size_t               bits;
   size_t               bytes;
   char                 buf[INET6_ADDRSTRLEN + sizeof("/128")];
   char                *sep;

   if (ares_strlen(src) >= sizeof buf) {
     SET_SOCKERRNO(EMSGSIZE);
     return -1;
   }
   ares_strcpy(buf, src, sizeof buf);

   sep = strchr(buf, '/');
   if (sep != NULL) {
     *sep++ = '\0';
   }

   ret = ares_inet_pton6(buf, (unsigned char *)&in6);
   if (ret != 1) {
     return -1;
   }

   if (sep == NULL) {
     bits = 128;
   } else {
     if (!getbits(sep, &bits)) {
       SET_SOCKERRNO(ENOENT);
       return -1;
     }
   }

   bytes = (bits + 7) / 8;
   if (bytes > size) {
     SET_SOCKERRNO(EMSGSIZE);
     return -1;
   }
   memcpy(dst, &in6, bytes);
   return (int)bits;
 }

 /*
  * int
  * inet_net_pton(af, src, dst, size)
  *      convert network number from presentation to network format.
  *      accepts hex octets, hex strings, decimal octets, and /CIDR.
  *      "size" is in bytes and describes "dst".
  * return:
  *      number of bits, either imputed classfully or specified with /CIDR,
  *      or -1 if some failure occurred (check errno).  ENOENT means it was
  *      not a valid network specification.
  * author:
  *      Paul Vixie (ISC), June 1996
  *
  */
 int ares_inet_net_pton(int af, const char *src, void *dst, size_t size)
 {
   switch (af) {
     case AF_INET:
       return ares_inet_net_pton_ipv4(src, dst, size);
     case AF_INET6:
       return ares_inet_net_pton_ipv6(src, dst, size);
     default:
       return -1;
   }
 }

 int ares_inet_pton(int af, const char *src, void *dst)
 {
   int    result;
   size_t size;

   if (af == AF_INET) {
     size = sizeof(struct in_addr);
   } else if (af == AF_INET6) {
     size = sizeof(struct ares_in6_addr);
   } else {
     SET_SOCKERRNO(EAFNOSUPPORT);
     return -1;
   }
   result = ares_inet_net_pton(af, src, dst, size);
   if (result == -1 && SOCKERRNO == ENOENT) {
     return 0;
   }
   return (result > -1) ? 1 : -1;
 }
	/*
	* Copyright (c) 2012 by Gilles Chehade <gilles@openbsd.org>
	* 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 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.
	*
	* SPDX-License-Identifier: MIT
	*/

	#include "ares_private.h"

	#ifdef HAVE_NETINET_IN_H
	# include <netinet/in.h>
	#endif
	#ifdef HAVE_ARPA_INET_H
	# include <arpa/inet.h>
	#endif

	#include "ares_nameser.h"

	#include "ares_ipv6.h"
	#include "ares_inet_net_pton.h"

	#ifdef USE_WINSOCK
	# define SOCKERRNO ((int)WSAGetLastError())
	# define SET_SOCKERRNO(x) (WSASetLastError((int)(x)))
	# undef EMSGSIZE
	# define EMSGSIZE WSAEMSGSIZE
	# undef ENOENT
	# define ENOENT WSA_INVALID_PARAMETER
	# undef EAFNOSUPPORT
	# define EAFNOSUPPORT WSAEAFNOSUPPORT
	#else
	# define SOCKERRNO (errno)
	# define SET_SOCKERRNO(x) (errno = (x))
	#endif

	const struct ares_in6_addr ares_in6addr_any = { { { 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0 } } };

	/*
	* static int
	* inet_net_pton_ipv4(src, dst, size)
	* convert IPv4 network number from presentation to network format.
	* accepts hex octets, hex strings, decimal octets, and /CIDR.
	* "size" is in bytes and describes "dst".
	* return:
	* number of bits, either imputed classfully or specified with /CIDR,
	* or -1 if some failure occurred (check errno). ENOENT means it was
	* not an IPv4 network specification.
	* note:
	* network byte order assumed. this means 192.5.5.240/28 has
	* 0b11110000 in its fourth octet.
	* note:
	* On Windows we store the error in the thread errno, not
	* in the winsock error code. This is to avoid losing the
	* actual last winsock error. So use macro ERRNO to fetch the
	* errno this function sets when returning (-1), not SOCKERRNO.
	* author:
	* Paul Vixie (ISC), June 1996
	*/
	static int ares_inet_net_pton_ipv4(const char src, unsigned char dst,
	size_t size)
	{
	static const char xdigits[] = "0123456789abcdef";
	static const char digits[] = "0123456789";
	int n;
	int ch;
	int tmp = 0;
	int dirty;
	int bits;
	const unsigned char *odst = dst;

	ch = *src++;
	if (ch == '0' && (src[0] == 'x' \|\| src[0] == 'X') && ares_isascii(src[1]) &&
	ares_isxdigit(src[1])) {
	/* Hexadecimal: Eat nybble string. */
	if (!size) {
	goto emsgsize;
	}
	dirty = 0;
	src++; /* skip x or X. */
	while ((ch = *src++) != '\0' && ares_isascii(ch) && ares_isxdigit(ch)) {
	if (ares_isupper(ch)) {
	ch = ares_tolower((unsigned char)ch);
	}
	n = (int)(strchr(xdigits, ch) - xdigits);
	if (dirty == 0) {
	tmp = n;
	} else {
	tmp = (tmp << 4) \| n;
	}
	if (++dirty == 2) {
	if (!size--) {
	goto emsgsize;
	}
	*dst++ = (unsigned char)tmp;
	dirty = 0;
	}
	}
	if (dirty) { /* Odd trailing nybble? */
	if (!size--) {
	goto emsgsize;
	}
	*dst++ = (unsigned char)(tmp << 4);
	}
	} else if (ares_isascii(ch) && ares_isdigit(ch)) {
	/* Decimal: eat dotted digit string. */
	for (;;) {
	tmp = 0;
	do {
	n = (int)(strchr(digits, ch) - digits);
	tmp *= 10;
	tmp += n;
	if (tmp > 255) {
	goto enoent;
	}
	} while ((ch = *src++) != '\0' && ares_isascii(ch) && ares_isdigit(ch));
	if (!size--) {
	goto emsgsize;
	}
	*dst++ = (unsigned char)tmp;
	if (ch == '\0' \|\| ch == '/') {
	break;
	}
	if (ch != '.') {
	goto enoent;
	}
	ch = *src++;
	if (!ares_isascii(ch) \|\| !ares_isdigit(ch)) {
	goto enoent;
	}
	}
	} else {
	goto enoent;
	}

	bits = -1;
	if (ch == '/' && ares_isascii(src[0]) && ares_isdigit(src[0]) && dst > odst) {
	/* CIDR width specifier. Nothing can follow it. */
	ch = src++; / Skip over the /. */
	bits = 0;
	do {
	n = (int)(strchr(digits, ch) - digits);
	bits *= 10;
	bits += n;
	if (bits > 32) {
	goto enoent;
	}
	} while ((ch = *src++) != '\0' && ares_isascii(ch) && ares_isdigit(ch));
	if (ch != '\0') {
	goto enoent;
	}
	}

	/* Firey death and destruction unless we prefetched EOS. */
	if (ch != '\0') {
	goto enoent;
	}

	/* If nothing was written to the destination, we found no address. */
	if (dst == odst) {
	goto enoent; /* LCOV_EXCL_LINE: all valid paths above increment dst */
	}
	/* If no CIDR spec was given, infer width from net class. */
	if (bits == -1) {
	if (odst >= 240) { / Class E */
	bits = 32;
	} else if (odst >= 224) { / Class D */
	bits = 8;
	} else if (odst >= 192) { / Class C */
	bits = 24;
	} else if (odst >= 128) { / Class B */
	bits = 16;
	} else { /* Class A */
	bits = 8;
	}
	/* If imputed mask is narrower than specified octets, widen. */
	if (bits < ((dst - odst) * 8)) {
	bits = (int)(dst - odst) * 8;
	}
	/*
	* If there are no additional bits specified for a class D
	* address adjust bits to 4.
	*/
	if (bits == 8 && *odst == 224) {
	bits = 4;
	}
	}
	/* Extend network to cover the actual mask. */
	while (bits > ((dst - odst) * 8)) {
	if (!size--) {
	goto emsgsize;
	}
	*dst++ = '\0';
	}
	return bits;

	enoent:
	SET_SOCKERRNO(ENOENT);
	return -1;

	emsgsize:
	SET_SOCKERRNO(EMSGSIZE);
	return -1;
	}

	static int getbits(const char src, size_t bitsp)
	{
	static const char digits[] = "0123456789";
	size_t n;
	size_t val;
	char ch;

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

	pch = strchr(digits, ch);
	if (pch != NULL) {
	if (n++ != 0 && val == 0) { /* no leading zeros */
	return 0;
	}
	val *= 10;
	val += (size_t)(pch - digits);
	if (val > 128) { /* range */
	return 0;
	}
	continue;
	}
	return 0;
	}
	if (n == 0) {
	return 0;
	}
	*bitsp = val;
	return 1;
	}

	static int ares_inet_pton6(const char src, unsigned char dst)
	{
	static const char xdigits_l[] = "0123456789abcdef";
	static const char xdigits_u[] = "0123456789ABCDEF";
	unsigned char tmp[NS_IN6ADDRSZ];
	unsigned char *tp;
	unsigned char *endp;
	unsigned char *colonp;
	const char *xdigits;
	const char *curtok;
	int ch;
	int saw_xdigit;
	int count_xdigit;
	unsigned int val;

	memset((tp = tmp), '\0', NS_IN6ADDRSZ);
	endp = tp + NS_IN6ADDRSZ;
	colonp = NULL;
	/* Leading :: requires some special handling. */
	if (*src == ':') {
	if (*++src != ':') {
	goto enoent;
	}
	}
	curtok = src;
	saw_xdigit = count_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) {
	if (count_xdigit >= 4) {
	goto enoent;
	}
	val <<= 4;
	val \|= (unsigned int)(pch - xdigits);
	if (val > 0xffff) {
	goto enoent;
	}
	saw_xdigit = 1;
	count_xdigit++;
	continue;
	}
	if (ch == ':') {
	curtok = src;
	if (!saw_xdigit) {
	if (colonp) {
	goto enoent;
	}
	colonp = tp;
	continue;
	} else if (*src == '\0') {
	goto enoent;
	}
	if (tp + NS_INT16SZ > endp) {
	goto enoent;
	}
	*tp++ = (unsigned char)(val >> 8) & 0xff;
	*tp++ = (unsigned char)val & 0xff;
	saw_xdigit = 0;
	count_xdigit = 0;
	val = 0;
	continue;
	}
	if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
	ares_inet_net_pton_ipv4(curtok, tp, NS_INADDRSZ) > 0) {
	tp += NS_INADDRSZ;
	saw_xdigit = 0;
	break; /* '\0' was seen by inet_pton4(). */
	}
	goto enoent;
	}
	if (saw_xdigit) {
	if (tp + NS_INT16SZ > endp) {
	goto enoent;
	}
	*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 = (int)(tp - colonp);
	int i;

	if (tp == endp) {
	goto enoent;
	}
	for (i = 1; i <= n; i++) {
	endp[-i] = colonp[n - i];
	colonp[n - i] = 0;
	}
	tp = endp;
	}
	if (tp != endp) {
	goto enoent;
	}

	memcpy(dst, tmp, NS_IN6ADDRSZ);
	return 1;

	enoent:
	SET_SOCKERRNO(ENOENT);
	return -1;
	}

	static int ares_inet_net_pton_ipv6(const char src, unsigned char dst,
	size_t size)
	{
	struct ares_in6_addr in6;
	int ret;
	size_t bits;
	size_t bytes;
	char buf[INET6_ADDRSTRLEN + sizeof("/128")];
	char *sep;

	if (ares_strlen(src) >= sizeof buf) {
	SET_SOCKERRNO(EMSGSIZE);
	return -1;
	}
	ares_strcpy(buf, src, sizeof buf);

	sep = strchr(buf, '/');
	if (sep != NULL) {
	*sep++ = '\0';
	}

	ret = ares_inet_pton6(buf, (unsigned char *)&in6);
	if (ret != 1) {
	return -1;
	}

	if (sep == NULL) {
	bits = 128;
	} else {
	if (!getbits(sep, &bits)) {
	SET_SOCKERRNO(ENOENT);
	return -1;
	}
	}

	bytes = (bits + 7) / 8;
	if (bytes > size) {
	SET_SOCKERRNO(EMSGSIZE);
	return -1;
	}
	memcpy(dst, &in6, bytes);
	return (int)bits;
	}

	/*
	* int
	* inet_net_pton(af, src, dst, size)
	* convert network number from presentation to network format.
	* accepts hex octets, hex strings, decimal octets, and /CIDR.
	* "size" is in bytes and describes "dst".
	* return:
	* number of bits, either imputed classfully or specified with /CIDR,
	* or -1 if some failure occurred (check errno). ENOENT means it was
	* not a valid network specification.
	* author:
	* Paul Vixie (ISC), June 1996
	*
	*/
	int ares_inet_net_pton(int af, const char src, void dst, size_t size)
	{
	switch (af) {
	case AF_INET:
	return ares_inet_net_pton_ipv4(src, dst, size);
	case AF_INET6:
	return ares_inet_net_pton_ipv6(src, dst, size);
	default:
	return -1;
	}
	}

	int ares_inet_pton(int af, const char src, void dst)
	{
	int result;
	size_t size;

	if (af == AF_INET) {
	size = sizeof(struct in_addr);
	} else if (af == AF_INET6) {
	size = sizeof(struct ares_in6_addr);
	} else {
	SET_SOCKERRNO(EAFNOSUPPORT);
	return -1;
	}
	result = ares_inet_net_pton(af, src, dst, size);
	if (result == -1 && SOCKERRNO == ENOENT) {
	return 0;
	}
	return (result > -1) ? 1 : -1;
	}