/* Copyright (C) 1996-2018 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 <stddef.h>
#include "nsswitch.h"
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <resolv/resolv-internal.h>
#include <resolv/resolv_context.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;
/* 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;
enum nss_status status;
struct resolv_context *ctx = __resolv_context_get ();
if (ctx == NULL)
{
*errnop = errno;
*herrnop = NETDB_INTERNAL;
return NSS_STATUS_UNAVAIL;
}
net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024);
anslen = __res_context_search
(ctx, name, C_IN, T_PTR, net_buffer.buf->buf,
1024, &net_buffer.ptr, NULL, NULL, NULL, NULL);
if (anslen < 0)
{
/* Nothing found. */
*errnop = errno;
if (net_buffer.buf != orig_net_buffer)
free (net_buffer.buf);
__resolv_context_put (ctx);
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);
__resolv_context_put (ctx);
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;
uint32_t net2;
int olderr = errno;
/* No net address lookup for IPv6 yet. */
if (type != AF_INET)
return NSS_STATUS_UNAVAIL;
struct resolv_context *ctx = __resolv_context_get ();
if (ctx == NULL)
{
*errnop = errno;
*herrnop = NETDB_INTERNAL;
return NSS_STATUS_UNAVAIL;
}
net2 = (uint32_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 = __res_context_query (ctx, qbuf, C_IN, T_PTR, net_buffer.buf->buf,
1024, &net_buffer.ptr, NULL, 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);
__resolv_context_put (ctx);
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;
}
__resolv_context_put (ctx);
return status;
}
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 = __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;
if (end_of_message - cp < 10)
{
__set_h_errno (NO_RECOVERY);
return NSS_STATUS_UNAVAIL;
}
int type, class;
GETSHORT (type, cp);
GETSHORT (class, cp);
cp += INT32SZ; /* TTL */
uint16_t rdatalen;
GETSHORT (rdatalen, cp);
if (end_of_message - cp < rdatalen)
{
__set_h_errno (NO_RECOVERY);
return NSS_STATUS_UNAVAIL;
}
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 += rdatalen;
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;
}
}
else
/* Skip over unknown record data. */
cp += rdatalen;
}
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;
for (ap = result->n_aliases; *ap != NULL; ++ap)
{
/* 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;
}