[thirdparty/glibc.git] / resolv / nss_dns / dns-network.c

/* Copyright (C) 1996-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Extended from original form by Ulrich Drepper <drepper@cygnus.com>, 1996.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

/* Parts of this file are plain copies of the file `getnetnamadr.c' from
   the bind package and it has the following copyright.  */

/* Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
 *      Dep. Matematica Universidade de Coimbra, Portugal, Europe
 *
 * 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.
 */
/*
 * Copyright (c) 1983, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>

#include "nsswitch.h"
#include <arpa/inet.h>

/* Maximum number of aliases we allow.  */
#define MAX_NR_ALIASES	48


#if PACKETSZ > 65536
# define MAXPACKET	PACKETSZ
#else
# define MAXPACKET	65536
#endif


typedef enum
{
  BYADDR,
  BYNAME
} lookup_method;


/* We need this time later.  */
typedef union querybuf
{
  HEADER hdr;
  u_char buf[MAXPACKET];
} querybuf;

/* These functions are defined in res_comp.c.  */
#define NS_MAXCDNAME	255	/* maximum compressed domain name */
extern int __ns_name_ntop (const u_char *, char *, size_t) __THROW;
extern int __ns_name_unpack (const u_char *, const u_char *,
			     const u_char *, u_char *, size_t) __THROW;


/* Prototypes for local functions.  */
static enum nss_status getanswer_r (const querybuf *answer, int anslen,
				    struct netent *result, char *buffer,
				    size_t buflen, int *errnop, int *h_errnop,
				    lookup_method net_i);


enum nss_status
_nss_dns_getnetbyname_r (const char *name, struct netent *result,
			 char *buffer, size_t buflen, int *errnop,
			 int *herrnop)
{
  /* Return entry for network with NAME.  */
  union
  {
    querybuf *buf;
    u_char *ptr;
  } net_buffer;
  querybuf *orig_net_buffer;
  int anslen;
  char *qbuf;
  enum nss_status status;

  if (__res_maybe_init (&_res, 0) == -1)
    return NSS_STATUS_UNAVAIL;

  qbuf = strdupa (name);

  net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024);

  anslen = __libc_res_nsearch (&_res, qbuf, C_IN, T_PTR, net_buffer.buf->buf,
			       1024, &net_buffer.ptr, NULL, NULL, NULL);
  if (anslen < 0)
    {
      /* Nothing found.  */
      *errnop = errno;
      if (net_buffer.buf != orig_net_buffer)
	free (net_buffer.buf);
      return (errno == ECONNREFUSED
	      || errno == EPFNOSUPPORT
	      || errno == EAFNOSUPPORT)
	? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
    }

  status = getanswer_r (net_buffer.buf, anslen, result, buffer, buflen,
			errnop, herrnop, BYNAME);
  if (net_buffer.buf != orig_net_buffer)
    free (net_buffer.buf);
  return status;
}


enum nss_status
_nss_dns_getnetbyaddr_r (uint32_t net, int type, struct netent *result,
			 char *buffer, size_t buflen, int *errnop,
			 int *herrnop)
{
  /* Return entry for network with NAME.  */
  enum nss_status status;
  union
  {
    querybuf *buf;
    u_char *ptr;
  } net_buffer;
  querybuf *orig_net_buffer;
  unsigned int net_bytes[4];
  char qbuf[MAXDNAME];
  int cnt, anslen;
  u_int32_t net2;
  int olderr = errno;

  /* No net address lookup for IPv6 yet.  */
  if (type != AF_INET)
    return NSS_STATUS_UNAVAIL;

  if (__res_maybe_init (&_res, 0) == -1)
    return NSS_STATUS_UNAVAIL;

  net2 = (u_int32_t) net;
  for (cnt = 4; net2 != 0; net2 >>= 8)
    net_bytes[--cnt] = net2 & 0xff;

  switch (cnt)
    {
    case 3:
      /* Class A network.  */
      sprintf (qbuf, "0.0.0.%u.in-addr.arpa", net_bytes[3]);
      break;
    case 2:
      /* Class B network.  */
      sprintf (qbuf, "0.0.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2]);
      break;
    case 1:
      /* Class C network.  */
      sprintf (qbuf, "0.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
	       net_bytes[1]);
      break;
    case 0:
      /* Class D - E network.  */
      sprintf (qbuf, "%u.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
	       net_bytes[1], net_bytes[0]);
      break;
    }

  net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024);

  anslen = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, net_buffer.buf->buf,
			      1024, &net_buffer.ptr, NULL, NULL, NULL);
  if (anslen < 0)
    {
      /* Nothing found.  */
      int err = errno;
      __set_errno (olderr);
      if (net_buffer.buf != orig_net_buffer)
	free (net_buffer.buf);
      return (err == ECONNREFUSED
	      || err == EPFNOSUPPORT
	      || err == EAFNOSUPPORT)
	? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
    }

  status = getanswer_r (net_buffer.buf, anslen, result, buffer, buflen,
			errnop, herrnop, BYADDR);
  if (net_buffer.buf != orig_net_buffer)
    free (net_buffer.buf);
  if (status == NSS_STATUS_SUCCESS)
    {
      /* Strip trailing zeros.  */
      unsigned int u_net = net;	/* Maybe net should be unsigned?  */

      while ((u_net & 0xff) == 0 && u_net != 0)
	u_net >>= 8;
      result->n_net = u_net;
    }

  return status;
}


#undef offsetof
#define offsetof(Type, Member) ((size_t) &((Type *) NULL)->Member)

static enum nss_status
getanswer_r (const querybuf *answer, int anslen, struct netent *result,
	     char *buffer, size_t buflen, int *errnop, int *h_errnop,
	     lookup_method net_i)
{
  /*
   * Find first satisfactory answer
   *
   *      answer --> +------------+  ( MESSAGE )
   *                 |   Header   |
   *                 +------------+
   *                 |  Question  | the question for the name server
   *                 +------------+
   *                 |   Answer   | RRs answering the question
   *                 +------------+
   *                 | Authority  | RRs pointing toward an authority
   *                 | Additional | RRs holding additional information
   *                 +------------+
   */
  struct net_data
  {
    char *aliases[MAX_NR_ALIASES];
    char linebuffer[0];
  } *net_data;

  uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct net_data);
  buffer += pad;

  if (__glibc_unlikely (buflen < sizeof (*net_data) + pad))
    {
      /* The buffer is too small.  */
    too_small:
      *errnop = ERANGE;
      *h_errnop = NETDB_INTERNAL;
      return NSS_STATUS_TRYAGAIN;
    }
  buflen -= pad;

  net_data = (struct net_data *) buffer;
  int linebuflen = buflen - offsetof (struct net_data, linebuffer);
  if (buflen - offsetof (struct net_data, linebuffer) != linebuflen)
    linebuflen = INT_MAX;
  const unsigned char *end_of_message = &answer->buf[anslen];
  const HEADER *header_pointer = &answer->hdr;
  /* #/records in the answer section.  */
  int answer_count =  ntohs (header_pointer->ancount);
  /* #/entries in the question section.  */
  int question_count = ntohs (header_pointer->qdcount);
  char *bp = net_data->linebuffer;
  const unsigned char *cp = &answer->buf[HFIXEDSZ];
  char **alias_pointer;
  int have_answer;
  u_char packtmp[NS_MAXCDNAME];

  if (question_count == 0)
    {
      /* FIXME: the Sun version uses for host name lookup an additional
	 parameter for pointing to h_errno.  this is missing here.
	 OSF/1 has a per-thread h_errno variable.  */
      if (header_pointer->aa != 0)
	{
	  __set_h_errno (HOST_NOT_FOUND);
	  return NSS_STATUS_NOTFOUND;
	}
      else
	{
	  __set_h_errno (TRY_AGAIN);
	  return NSS_STATUS_TRYAGAIN;
	}
    }

  /* Skip the question part.  */
  while (question_count-- > 0)
    {
      int n = __dn_skipname (cp, end_of_message);
      if (n < 0 || end_of_message - (cp + n) < QFIXEDSZ)
       {
         __set_h_errno (NO_RECOVERY);
         return NSS_STATUS_UNAVAIL;
       }
      cp += n + QFIXEDSZ;
    }

  alias_pointer = result->n_aliases = &net_data->aliases[0];
  *alias_pointer = NULL;
  have_answer = 0;

  while (--answer_count >= 0 && cp < end_of_message)
    {
      int n = dn_expand (answer->buf, end_of_message, cp, bp, linebuflen);
      int type, class;

      n = __ns_name_unpack (answer->buf, end_of_message, cp,
			    packtmp, sizeof packtmp);
      if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
	{
	  if (errno == EMSGSIZE)
	    goto too_small;

	  n = -1;
	}

      if (n > 0 && bp[0] == '.')
	bp[0] = '\0';

      if (n < 0 || res_dnok (bp) == 0)
	break;
      cp += n;
      GETSHORT (type, cp);
      GETSHORT (class, cp);
      cp += INT32SZ;		/* TTL */
      GETSHORT (n, cp);

      if (class == C_IN && type == T_PTR)
	{
	  n = __ns_name_unpack (answer->buf, end_of_message, cp,
				packtmp, sizeof packtmp);
	  if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
	    {
	      if (errno == EMSGSIZE)
		goto too_small;

	      n = -1;
	    }

	  if (n < 0 || !res_hnok (bp))
	    {
	      /* XXX What does this mean?  The original form from bind
		 returns NULL. Incrementing cp has no effect in any case.
		 What should I return here. ??? */
	      cp += n;
	      return NSS_STATUS_UNAVAIL;
	    }
	  cp += n;
         if (alias_pointer + 2 < &net_data->aliases[MAX_NR_ALIASES])
           {
             *alias_pointer++ = bp;
             n = strlen (bp) + 1;
             bp += n;
             linebuflen -= n;
             result->n_addrtype = class == C_IN ? AF_INET : AF_UNSPEC;
             ++have_answer;
           }
	}
    }

  if (have_answer)
    {
      *alias_pointer = NULL;
      switch (net_i)
	{
	case BYADDR:
	  result->n_name = *result->n_aliases++;
	  result->n_net = 0L;
	  return NSS_STATUS_SUCCESS;

	case BYNAME:
	  {
	    char **ap = result->n_aliases++;
	    while (*ap != NULL)
	      {
		/* Check each alias name for being of the forms:
		   4.3.2.1.in-addr.arpa		= net 1.2.3.4
		   3.2.1.in-addr.arpa		= net 0.1.2.3
		   2.1.in-addr.arpa		= net 0.0.1.2
		   1.in-addr.arpa		= net 0.0.0.1
		*/
		uint32_t val = 0;	/* Accumulator for n_net value.  */
		unsigned int shift = 0; /* Which part we are parsing now.  */
		const char *p = *ap; /* Consuming the string.  */
		do
		  {
		    /* Match the leading 0 or 0[xX] base indicator.  */
		    unsigned int base = 10;
		    if (*p == '0' && p[1] != '.')
		      {
			base = 8;
			++p;
			if (*p == 'x' || *p == 'X')
			  {
			    base = 16;
			    ++p;
			    if (*p == '.')
			      break; /* No digit here.  Give up on alias.  */
			  }
			if (*p == '\0')
			  break;
		      }

		    uint32_t part = 0; /* Accumulates this part's number.  */
		    do
		      {
			if (isdigit (*p) && (*p - '0' < base))
			  part = (part * base) + (*p - '0');
			else if (base == 16 && isxdigit (*p))
			  part = (part << 4) + 10 + (tolower (*p) - 'a');
			++p;
		      } while (*p != '\0' && *p != '.');

		    if (*p != '.')
		      break;	/* Bad form.  Give up on this name.  */

		    /* Install this as the next more significant byte.  */
		    val |= part << shift;
		    shift += 8;
		    ++p;

		    /* If we are out of digits now, there are two cases:
		       1. We are done with digits and now see "in-addr.arpa".
		       2. This is not the droid we are looking for.  */
		    if (!isdigit (*p) && !strcasecmp (p, "in-addr.arpa"))
		      {
			result->n_net = val;
			return NSS_STATUS_SUCCESS;
		      }

		    /* Keep going when we have seen fewer than 4 parts.  */
		  } while (shift < 32);
	      }
	  }
	  break;
	}
    }

  __set_h_errno (TRY_AGAIN);
  return NSS_STATUS_TRYAGAIN;
}
Commit	Line	Data
d4697bc9	1	/* Copyright (C) 1996-2014 Free Software Foundation, Inc.
84384f5b UD	2	This file is part of the GNU C Library.
84384f5b UD	3	Extended from original form by Ulrich Drepper <drepper@cygnus.com>, 1996.
5f0e6fc7	4
84384f5b	5	The GNU C Library is free software; you can redistribute it and/or
41bdb6e2 AJ	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
5f0e6fc7	9
84384f5b UD	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
41bdb6e2	13	Lesser General Public License for more details.
5f0e6fc7	14
41bdb6e2	15	You should have received a copy of the GNU Lesser General Public
59ba27a6 PE	16	License along with the GNU C Library; if not, see
59ba27a6 PE	17	<http://www.gnu.org/licenses/>. */
5f0e6fc7 RM	18
	19	/* Parts of this file are plain copies of the file `getnetnamadr.c' from
	20	the bind package and it has the following copyright. */
	21
	22	/* Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
	23	* Dep. Matematica Universidade de Coimbra, Portugal, Europe
	24	*
	25	* Permission to use, copy, modify, and distribute this software for any
	26	* purpose with or without fee is hereby granted, provided that the above
	27	* copyright notice and this permission notice appear in all copies.
	28	*/
	29	/*
	30	* Copyright (c) 1983, 1993
	31	* The Regents of the University of California. All rights reserved.
	32	*
	33	* Redistribution and use in source and binary forms, with or without
	34	* modification, are permitted provided that the following conditions
	35	* are met:
	36	* 1. Redistributions of source code must retain the above copyright
	37	* notice, this list of conditions and the following disclaimer.
	38	* 2. Redistributions in binary form must reproduce the above copyright
	39	* notice, this list of conditions and the following disclaimer in the
	40	* documentation and/or other materials provided with the distribution.
5f0e6fc7 RM	41	* 4. Neither the name of the University nor the names of its contributors
	42	* may be used to endorse or promote products derived from this software
	43	* without specific prior written permission.
	44	*
	45	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	46	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	47	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	48	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	49	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	50	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	51	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	52	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	53	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	54	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	55	* SUCH DAMAGE.
	56	*/
	57
	58	#include <ctype.h>
	59	#include <errno.h>
	60	#include <netdb.h>
	61	#include <stdio.h>
	62	#include <stdlib.h>
	63	#include <string.h>
e054f494	64	#include <stdint.h>
5f0e6fc7 RM	65
	66	#include "nsswitch.h"
	67	#include <arpa/inet.h>
	68
	69	/* Maximum number of aliases we allow. */
	70	#define MAX_NR_ALIASES 48
	71
	72
870d19de RM	73	#if PACKETSZ > 65536
870d19de RM	74	# define MAXPACKET PACKETSZ
5f0e6fc7	75	#else
870d19de	76	# define MAXPACKET 65536
5f0e6fc7 RM	77	#endif
	78
	79
	80	typedef enum
	81	{
	82	BYADDR,
	83	BYNAME
	84	} lookup_method;
	85
	86
	87	/* We need this time later. */
	88	typedef union querybuf
	89	{
	90	HEADER hdr;
	91	u_char buf[MAXPACKET];
	92	} querybuf;
	93
8d8c6efa UD	94	/* These functions are defined in res_comp.c. */
8d8c6efa UD	95	#define NS_MAXCDNAME 255 /* maximum compressed domain name */
79937577 UD	96	extern int __ns_name_ntop (const u_char , char , size_t) __THROW;
	97	extern int __ns_name_unpack (const u_char , const u_char ,
	98	const u_char , u_char , size_t) __THROW;
8d8c6efa	99
5f0e6fc7	100
6d52618b	101	/* Prototypes for local functions. */
84384f5b UD	102	static enum nss_status getanswer_r (const querybuf *answer, int anslen,
84384f5b UD	103	struct netent result, char buffer,
2f1687b9 UD	104	size_t buflen, int errnop, int h_errnop,
2f1687b9 UD	105	lookup_method net_i);
5f0e6fc7 RM	106
5f0e6fc7 RM	107
84384f5b	108	enum nss_status
5f0e6fc7	109	_nss_dns_getnetbyname_r (const char name, struct netent result,
51eecc4a AJ	110	char buffer, size_t buflen, int errnop,
51eecc4a AJ	111	int *herrnop)
5f0e6fc7 RM	112	{
5f0e6fc7 RM	113	/* Return entry for network with NAME. */
16b66062 AJ	114	union
	115	{
	116	querybuf *buf;
	117	u_char *ptr;
	118	} net_buffer;
	119	querybuf *orig_net_buffer;
0420d888	120	int anslen;
5f0e6fc7	121	char *qbuf;
6166815d	122	enum nss_status status;
5f0e6fc7	123
87bb6b6c	124	if (__res_maybe_init (&_res, 0) == -1)
b43b13ac UD	125	return NSS_STATUS_UNAVAIL;
b43b13ac UD	126
5f0e6fc7	127	qbuf = strdupa (name);
6166815d	128
16b66062	129	net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024);
6166815d	130
16b66062	131	anslen = __libc_res_nsearch (&_res, qbuf, C_IN, T_PTR, net_buffer.buf->buf,
b7da31a1	132	1024, &net_buffer.ptr, NULL, NULL, NULL);
5f0e6fc7	133	if (anslen < 0)
67479a70 UD	134	{
	135	/* Nothing found. */
	136	*errnop = errno;
16b66062 AJ	137	if (net_buffer.buf != orig_net_buffer)
16b66062 AJ	138	free (net_buffer.buf);
67479a70 UD	139	return (errno == ECONNREFUSED
	140	\|\| errno == EPFNOSUPPORT
	141	\|\| errno == EAFNOSUPPORT)
	142	? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
	143	}
5f0e6fc7	144
2f1687b9 UD	145	status = getanswer_r (net_buffer.buf, anslen, result, buffer, buflen,
2f1687b9 UD	146	errnop, herrnop, BYNAME);
16b66062 AJ	147	if (net_buffer.buf != orig_net_buffer)
16b66062 AJ	148	free (net_buffer.buf);
6166815d	149	return status;
5f0e6fc7 RM	150	}
	151
	152
84384f5b	153	enum nss_status
51eecc4a AJ	154	_nss_dns_getnetbyaddr_r (uint32_t net, int type, struct netent *result,
	155	char buffer, size_t buflen, int errnop,
	156	int *herrnop)
5f0e6fc7 RM	157	{
5f0e6fc7 RM	158	/* Return entry for network with NAME. */
84384f5b	159	enum nss_status status;
16b66062 AJ	160	union
	161	{
	162	querybuf *buf;
	163	u_char *ptr;
	164	} net_buffer;
	165	querybuf *orig_net_buffer;
5f0e6fc7 RM	166	unsigned int net_bytes[4];
5f0e6fc7 RM	167	char qbuf[MAXDNAME];
0420d888	168	int cnt, anslen;
5f0e6fc7	169	u_int32_t net2;
34816665	170	int olderr = errno;
5f0e6fc7 RM	171
	172	/* No net address lookup for IPv6 yet. */
	173	if (type != AF_INET)
	174	return NSS_STATUS_UNAVAIL;
	175
87bb6b6c	176	if (__res_maybe_init (&_res, 0) == -1)
b43b13ac	177	return NSS_STATUS_UNAVAIL;
51eecc4a	178
5f0e6fc7 RM	179	net2 = (u_int32_t) net;
	180	for (cnt = 4; net2 != 0; net2 >>= 8)
	181	net_bytes[--cnt] = net2 & 0xff;
	182
	183	switch (cnt)
	184	{
	185	case 3:
	186	/* Class A network. */
	187	sprintf (qbuf, "0.0.0.%u.in-addr.arpa", net_bytes[3]);
	188	break;
	189	case 2:
	190	/* Class B network. */
	191	sprintf (qbuf, "0.0.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2]);
	192	break;
	193	case 1:
	194	/* Class C network. */
	195	sprintf (qbuf, "0.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
	196	net_bytes[1]);
	197	break;
	198	case 0:
	199	/* Class D - E network. */
	200	sprintf (qbuf, "%u.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2],
	201	net_bytes[1], net_bytes[0]);
	202	break;
	203	}
	204
16b66062	205	net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024);
6166815d	206
16b66062	207	anslen = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, net_buffer.buf->buf,
b7da31a1	208	1024, &net_buffer.ptr, NULL, NULL, NULL);
5f0e6fc7	209	if (anslen < 0)
67479a70 UD	210	{
67479a70 UD	211	/* Nothing found. */
34816665 UD	212	int err = errno;
34816665 UD	213	__set_errno (olderr);
16b66062 AJ	214	if (net_buffer.buf != orig_net_buffer)
16b66062 AJ	215	free (net_buffer.buf);
34816665 UD	216	return (err == ECONNREFUSED
	217	\|\| err == EPFNOSUPPORT
	218	\|\| err == EAFNOSUPPORT)
67479a70 UD	219	? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND;
67479a70 UD	220	}
5f0e6fc7	221
2f1687b9 UD	222	status = getanswer_r (net_buffer.buf, anslen, result, buffer, buflen,
2f1687b9 UD	223	errnop, herrnop, BYADDR);
16b66062 AJ	224	if (net_buffer.buf != orig_net_buffer)
16b66062 AJ	225	free (net_buffer.buf);
5f0e6fc7 RM	226	if (status == NSS_STATUS_SUCCESS)
	227	{
	228	/* Strip trailing zeros. */
	229	unsigned int u_net = net; /* Maybe net should be unsigned? */
	230
	231	while ((u_net & 0xff) == 0 && u_net != 0)
	232	u_net >>= 8;
	233	result->n_net = u_net;
	234	}
	235
	236	return status;
	237	}
	238
	239
	240	#undef offsetof
	241	#define offsetof(Type, Member) ((size_t) &((Type *) NULL)->Member)
	242
84384f5b	243	static enum nss_status
5f0e6fc7	244	getanswer_r (const querybuf answer, int anslen, struct netent result,
2f1687b9 UD	245	char buffer, size_t buflen, int errnop, int *h_errnop,
2f1687b9 UD	246	lookup_method net_i)
5f0e6fc7 RM	247	{
	248	/*
	249	* Find first satisfactory answer
	250	*
	251	* answer --> +------------+ ( MESSAGE )
	252	* \| Header \|
	253	* +------------+
	254	* \| Question \| the question for the name server
	255	* +------------+
	256	* \| Answer \| RRs answering the question
	257	* +------------+
	258	* \| Authority \| RRs pointing toward an authority
	259	* \| Additional \| RRs holding additional information
	260	* +------------+
	261	*/
	262	struct net_data
	263	{
	264	char *aliases[MAX_NR_ALIASES];
	265	char linebuffer[0];
2f1687b9 UD	266	} *net_data;
	267
	268	uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct net_data);
	269	buffer += pad;
	270
a1ffb40e	271	if (__glibc_unlikely (buflen < sizeof (*net_data) + pad))
2f1687b9 UD	272	{
	273	/* The buffer is too small. */
	274	too_small:
	275	*errnop = ERANGE;
	276	*h_errnop = NETDB_INTERNAL;
	277	return NSS_STATUS_TRYAGAIN;
	278	}
	279	buflen -= pad;
	280
	281	net_data = (struct net_data *) buffer;
5f0e6fc7	282	int linebuflen = buflen - offsetof (struct net_data, linebuffer);
2f1687b9 UD	283	if (buflen - offsetof (struct net_data, linebuffer) != linebuflen)
2f1687b9 UD	284	linebuflen = INT_MAX;
9cfe5381	285	const unsigned char *end_of_message = &answer->buf[anslen];
5f0e6fc7 RM	286	const HEADER *header_pointer = &answer->hdr;
	287	/* #/records in the answer section. */
	288	int answer_count = ntohs (header_pointer->ancount);
	289	/* #/entries in the question section. */
	290	int question_count = ntohs (header_pointer->qdcount);
	291	char *bp = net_data->linebuffer;
9cfe5381	292	const unsigned char *cp = &answer->buf[HFIXEDSZ];
5f0e6fc7 RM	293	char **alias_pointer;
5f0e6fc7 RM	294	int have_answer;
8d8c6efa	295	u_char packtmp[NS_MAXCDNAME];
5f0e6fc7 RM	296
5f0e6fc7 RM	297	if (question_count == 0)
7ef90c15 UD	298	{
	299	/* FIXME: the Sun version uses for host name lookup an additional
	300	parameter for pointing to h_errno. this is missing here.
	301	OSF/1 has a per-thread h_errno variable. */
	302	if (header_pointer->aa != 0)
	303	{
	304	__set_h_errno (HOST_NOT_FOUND);
	305	return NSS_STATUS_NOTFOUND;
	306	}
	307	else
	308	{
	309	__set_h_errno (TRY_AGAIN);
	310	return NSS_STATUS_TRYAGAIN;
	311	}
	312	}
5f0e6fc7 RM	313
	314	/* Skip the question part. */
	315	while (question_count-- > 0)
9b57c1c1 RM	316	{
	317	int n = __dn_skipname (cp, end_of_message);
	318	if (n < 0 \|\| end_of_message - (cp + n) < QFIXEDSZ)
	319	{
	320	__set_h_errno (NO_RECOVERY);
	321	return NSS_STATUS_UNAVAIL;
	322	}
	323	cp += n + QFIXEDSZ;
	324	}
5f0e6fc7 RM	325
	326	alias_pointer = result->n_aliases = &net_data->aliases[0];
	327	*alias_pointer = NULL;
	328	have_answer = 0;
5f0e6fc7 RM	329
	330	while (--answer_count >= 0 && cp < end_of_message)
	331	{
	332	int n = dn_expand (answer->buf, end_of_message, cp, bp, linebuflen);
	333	int type, class;
	334
8d8c6efa UD	335	n = __ns_name_unpack (answer->buf, end_of_message, cp,
	336	packtmp, sizeof packtmp);
	337	if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
	338	{
	339	if (errno == EMSGSIZE)
2f1687b9	340	goto too_small;
8d8c6efa UD	341
	342	n = -1;
	343	}
	344
	345	if (n > 0 && bp[0] == '.')
	346	bp[0] = '\0';
	347
5f0e6fc7 RM	348	if (n < 0 \|\| res_dnok (bp) == 0)
	349	break;
	350	cp += n;
5f0e6fc7 RM	351	GETSHORT (type, cp);
	352	GETSHORT (class, cp);
	353	cp += INT32SZ; /* TTL */
	354	GETSHORT (n, cp);
	355
	356	if (class == C_IN && type == T_PTR)
	357	{
8d8c6efa UD	358	n = __ns_name_unpack (answer->buf, end_of_message, cp,
	359	packtmp, sizeof packtmp);
	360	if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1)
	361	{
	362	if (errno == EMSGSIZE)
2f1687b9	363	goto too_small;
8d8c6efa UD	364
	365	n = -1;
	366	}
	367
5f0e6fc7 RM	368	if (n < 0 \|\| !res_hnok (bp))
	369	{
	370	/* XXX What does this mean? The original form from bind
	371	returns NULL. Incrementing cp has no effect in any case.
	372	What should I return here. ??? */
	373	cp += n;
	374	return NSS_STATUS_UNAVAIL;
	375	}
	376	cp += n;
9b57c1c1 RM	377	if (alias_pointer + 2 < &net_data->aliases[MAX_NR_ALIASES])
	378	{
	379	*alias_pointer++ = bp;
	380	n = strlen (bp) + 1;
	381	bp += n;
	382	linebuflen -= n;
	383	result->n_addrtype = class == C_IN ? AF_INET : AF_UNSPEC;
	384	++have_answer;
	385	}
5f0e6fc7 RM	386	}
	387	}
	388
	389	if (have_answer)
	390	{
5f0e6fc7 RM	391	*alias_pointer = NULL;
	392	switch (net_i)
	393	{
	394	case BYADDR:
0bf5c050	395	result->n_name = *result->n_aliases++;
5f0e6fc7	396	result->n_net = 0L;
0bf5c050	397	return NSS_STATUS_SUCCESS;
5f0e6fc7	398
0bf5c050 RM	399	case BYNAME:
	400	{
	401	char **ap = result->n_aliases++;
	402	while (*ap != NULL)
	403	{
	404	/* Check each alias name for being of the forms:
	405	4.3.2.1.in-addr.arpa = net 1.2.3.4
	406	3.2.1.in-addr.arpa = net 0.1.2.3
	407	2.1.in-addr.arpa = net 0.0.1.2
	408	1.in-addr.arpa = net 0.0.0.1
	409	*/
	410	uint32_t val = 0; /* Accumulator for n_net value. */
	411	unsigned int shift = 0; /* Which part we are parsing now. */
	412	const char p = ap; /* Consuming the string. */
	413	do
	414	{
	415	/* Match the leading 0 or 0[xX] base indicator. */
	416	unsigned int base = 10;
	417	if (*p == '0' && p[1] != '.')
	418	{
	419	base = 8;
	420	++p;
	421	if (p == 'x' \|\| p == 'X')
	422	{
	423	base = 16;
	424	++p;
	425	if (*p == '.')
	426	break; /* No digit here. Give up on alias. */
	427	}
	428	if (*p == '\0')
	429	break;
	430	}
	431
	432	uint32_t part = 0; /* Accumulates this part's number. */
	433	do
	434	{
	435	if (isdigit (p) && (p - '0' < base))
	436	part = (part * base) + (*p - '0');
	437	else if (base == 16 && isxdigit (*p))
	438	part = (part << 4) + 10 + (tolower (*p) - 'a');
	439	++p;
	440	} while (p != '\0' && p != '.');
	441
	442	if (*p != '.')
	443	break; /* Bad form. Give up on this name. */
	444
	445	/* Install this as the next more significant byte. */
	446	val \|= part << shift;
	447	shift += 8;
	448	++p;
	449
	450	/* If we are out of digits now, there are two cases:
	451	1. We are done with digits and now see "in-addr.arpa".
	452	2. This is not the droid we are looking for. */
	453	if (!isdigit (*p) && !strcasecmp (p, "in-addr.arpa"))
	454	{
	455	result->n_net = val;
	456	return NSS_STATUS_SUCCESS;
	457	}
	458
	459	/* Keep going when we have seen fewer than 4 parts. */
	460	} while (shift < 32);
	461	}
	462	}
5f0e6fc7 RM	463	break;
5f0e6fc7 RM	464	}
5f0e6fc7 RM	465	}
5f0e6fc7 RM	466
a68b0d31	467	__set_h_errno (TRY_AGAIN);
5f0e6fc7 RM	468	return NSS_STATUS_TRYAGAIN;
5f0e6fc7 RM	469	}