glibc/resolv/res_mkquery.c

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/* Creation of DNS query packets.
Copyright (C) 1995-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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
Prefer https to http for gnu.org and fsf.org URLs Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
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<https://www.gnu.org/licenses/>. */
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/*
* Copyright (c) 1985, 1993
* The Regents of the University of California. All rights reserved.
*
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* 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.
*
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* 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.
Update. 1999-12-03 Andreas Jaeger <aj@suse.de> * nss/getXXbyYY.c: Include <resolv.h> (FUNCTION_NAME): Use res_ninit instead of res_init. * nss/getXXbyYY_r.c [NEED__RES]: Include <resolv.h> for _res declaration and prototypes. Remove extra _res declaration. (INTERNAL): Use thread aware res_ninit function. * inet/gethstbyad_r.c: Include <resolv.h>. * resolv/res_data.c: Update from Bind 8.2.2-P5. Moved res_init to res_libc.c. Disabled unneeded functions. * resolv/res_libc.c: New file. * Versions.def: Add version GLIBC_2.2 for libpthread. Add versions GLIBC_2.1 and GLIBC_2.2 for libresolv. * include/resolv.h: Add internal interfaces. * resolv/Makefile (routines): Add new files. (libresolv-routines): Likewise. (distribute): Likewise. * resolv/gethnamaddr.c: Use thread safe resolver functions. * resolv/nss_dns/dns-host.c: Likewise. * resolv/nss_dns/dns-network.c: Likewise. * resolv/arpa/nameser.h: Update from Bind 8.2.2-P5. * resolv/nsap_addr.c: Likewise. * resolv/res_comp.c: Likewise. * resolv/res_debug.c: Likewise. * resolv/res_init.c: Likewise. * resolv/res_mkquery.c: Likewise. * resolv/res_query.c: Likewise. * resolv/res_send.c: Likewise. * resolv/resolv.h: Likewise. * resolv/Versions: Add __res_state and __res_ninit with version GLIBC_2.2 to libc. Add new interfaces with version GLIBC_2.2 to libresolv. * resolv/Banner: Update. * include/arpa/nameser_compat.h: New file. * resolv/ns_name.c: New file from Bind 8.2.2-P5. * resolv/ns_netint.c: Likewise. * resolv/ns_parse.c: Likewise. * resolv/ns_print.c: Likewise. * resolv/ns_samedomain.c: Likewise. * resolv/ns_ttl.c: Likewise. * resolv/arpa/nameser_compat.h: Likewise. * resolv/res_debug.h: Likewise. Some patches are based on work done by Adam D. Bradley <artdodge@cs.bu.edu>. * sysdeps/unix/sysv/linux/configure.in: Remove check for ldconfig, set always use_ldconfig instead.
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*/
/*
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* Portions Copyright (c) 1993 by Digital Equipment Corporation.
*
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* 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, and that
* the name of Digital Equipment Corporation not be used in advertising or
* publicity pertaining to distribution of the document or software without
* specific, written prior permission.
*
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* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
* CORPORATION 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.
Update. 1999-12-03 Andreas Jaeger <aj@suse.de> * nss/getXXbyYY.c: Include <resolv.h> (FUNCTION_NAME): Use res_ninit instead of res_init. * nss/getXXbyYY_r.c [NEED__RES]: Include <resolv.h> for _res declaration and prototypes. Remove extra _res declaration. (INTERNAL): Use thread aware res_ninit function. * inet/gethstbyad_r.c: Include <resolv.h>. * resolv/res_data.c: Update from Bind 8.2.2-P5. Moved res_init to res_libc.c. Disabled unneeded functions. * resolv/res_libc.c: New file. * Versions.def: Add version GLIBC_2.2 for libpthread. Add versions GLIBC_2.1 and GLIBC_2.2 for libresolv. * include/resolv.h: Add internal interfaces. * resolv/Makefile (routines): Add new files. (libresolv-routines): Likewise. (distribute): Likewise. * resolv/gethnamaddr.c: Use thread safe resolver functions. * resolv/nss_dns/dns-host.c: Likewise. * resolv/nss_dns/dns-network.c: Likewise. * resolv/arpa/nameser.h: Update from Bind 8.2.2-P5. * resolv/nsap_addr.c: Likewise. * resolv/res_comp.c: Likewise. * resolv/res_debug.c: Likewise. * resolv/res_init.c: Likewise. * resolv/res_mkquery.c: Likewise. * resolv/res_query.c: Likewise. * resolv/res_send.c: Likewise. * resolv/resolv.h: Likewise. * resolv/Versions: Add __res_state and __res_ninit with version GLIBC_2.2 to libc. Add new interfaces with version GLIBC_2.2 to libresolv. * resolv/Banner: Update. * include/arpa/nameser_compat.h: New file. * resolv/ns_name.c: New file from Bind 8.2.2-P5. * resolv/ns_netint.c: Likewise. * resolv/ns_parse.c: Likewise. * resolv/ns_print.c: Likewise. * resolv/ns_samedomain.c: Likewise. * resolv/ns_ttl.c: Likewise. * resolv/arpa/nameser_compat.h: Likewise. * resolv/res_debug.h: Likewise. Some patches are based on work done by Adam D. Bradley <artdodge@cs.bu.edu>. * sysdeps/unix/sysv/linux/configure.in: Remove check for ldconfig, set always use_ldconfig instead.
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*/
/*
* Portions 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.
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*/
#include <stdint.h>
Update. Wed Aug 14 21:36:16 1996 Ulrich Drepper <drepper@cygnus.com> * stdlib/strtod.c (STRTOD): Correct assertion about size of wint_t and wchar_t. Reported by David Mosberger-Tang. Mon Aug 12 22:40:16 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * elf/dl-lookup.c (_dl_lookup_symbol): Remove fifth parameter RELOC_ADDR and make NOPLT a set of flags. All callers changed. Delete condition that checks for resolving to the location being filled in. Add condition to skip the executable's symbols if requested. * elf/link.h: Change declaration of _dl_lookup_symbol accordingly. (DL_LOOKUP_NOEXEC, DL_LOOKUP_NOPLT): New definitions. * elf/dl-reloc.c (RESOLVE): Remove second parameter and rename NOPLT to FLAGS. * elf/dl-runtime.c (RESOLVE): Likewise. * elf/rtld.c (RESOLVE): Likewise. * sysdeps/m68k/dl-machine.h (elf_machine_rela): Pass DL_LOOKUP_NOEXEC as second argument to the RESOLVE macro if processing a copy reloc, DL_LOOKUP_NOPLT for a jump slot reloc, zero otherwise. * sysdeps/alpha/dl-machine.h (elf_machine_rela): Likewise. * sysdeps/i386/dl-machine.h (elf_machine_rel): Likewise. * sysdeps/mips/dl-machine.h (elf_machine_rel): Likewise. Wed Aug 14 17:57:08 1996 Ulrich Drepper <drepper@cygnus.com> * MakeTAGS: Clean up use of --omit-header and -n for xgettext. * po/header.pot: Add empty line at end. Sun Aug 11 13:45:33 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * MakeTAGS (all-pot): Remove $P/errlist.pot, all error messages are now in $P/stdio-common.pot. (XGETTEXTFLAGS-errlist.pot): Variable removed. Mon Aug 12 19:25:03 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * Makerules (do-ar, o-iterator-doit): Compute path to autolock script at run time, not configure time. * config.make.in, configure.in: Undo previous change. Wed Aug 14 13:20:02 1996 Ulrich Drepper <drepper@cygnus.com> * sysdeps/unix/sysv/linux/i386/close.S: Push return value of thread on stack as argument for `_exit'. Reported by Andreas Schwab. Mon Aug 12 19:36:25 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * sysdeps/unix/sysv/linux/m68k/clone.S: New file. Wed Aug 14 04:22:35 1996 Richard Henderson <rth@tamu.edu> * elf/dl-load.c (_dl_map_object): Save name in malloced memory. (_dl_map_object_from_fd): Free name on error. Wed Aug 14 13:00:09 1996 Ulrich Drepper <drepper@cygnus.com> * string/strdup.c: Use result of memcpy to avoid reloading. Tue Aug 13 00:55:03 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * shadow/sgetspent_r.c (__sgetspent_r): Copy string to buffer, not the other way round. * resolv/Makefile (libresolv-routines): Add base64, inet_net_ntop, inet_net_pton, inet_net. * resolv/arpa/nameser.h (__BIND): Update version number. Mon Aug 12 19:03:22 1996 Thomas Bushnell n/BSG <thomas@psilocin.gnu.ai.mit.edu> * sysdeps/generic/gnu/types.h: Declare __fd_mask as `unsigned long'. * mach/Makefile (mach/mach_host.uh): Depend on $(objpfx)/mach-syscalls.mk. ($(objpfx)mach-shortcuts.h): Depend on $(objpfx)mach/mach_host.h. (This fixes a make loop; thanks to Marcus Daniels <marcus@sysc.pdx.edu> for the patch.)
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#include <sys/types.h>
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#include <sys/param.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <netdb.h>
#include <resolv/resolv-internal.h>
#include <resolv/resolv_context.h>
Update. 1999-12-03 Andreas Jaeger <aj@suse.de> * nss/getXXbyYY.c: Include <resolv.h> (FUNCTION_NAME): Use res_ninit instead of res_init. * nss/getXXbyYY_r.c [NEED__RES]: Include <resolv.h> for _res declaration and prototypes. Remove extra _res declaration. (INTERNAL): Use thread aware res_ninit function. * inet/gethstbyad_r.c: Include <resolv.h>. * resolv/res_data.c: Update from Bind 8.2.2-P5. Moved res_init to res_libc.c. Disabled unneeded functions. * resolv/res_libc.c: New file. * Versions.def: Add version GLIBC_2.2 for libpthread. Add versions GLIBC_2.1 and GLIBC_2.2 for libresolv. * include/resolv.h: Add internal interfaces. * resolv/Makefile (routines): Add new files. (libresolv-routines): Likewise. (distribute): Likewise. * resolv/gethnamaddr.c: Use thread safe resolver functions. * resolv/nss_dns/dns-host.c: Likewise. * resolv/nss_dns/dns-network.c: Likewise. * resolv/arpa/nameser.h: Update from Bind 8.2.2-P5. * resolv/nsap_addr.c: Likewise. * resolv/res_comp.c: Likewise. * resolv/res_debug.c: Likewise. * resolv/res_init.c: Likewise. * resolv/res_mkquery.c: Likewise. * resolv/res_query.c: Likewise. * resolv/res_send.c: Likewise. * resolv/resolv.h: Likewise. * resolv/Versions: Add __res_state and __res_ninit with version GLIBC_2.2 to libc. Add new interfaces with version GLIBC_2.2 to libresolv. * resolv/Banner: Update. * include/arpa/nameser_compat.h: New file. * resolv/ns_name.c: New file from Bind 8.2.2-P5. * resolv/ns_netint.c: Likewise. * resolv/ns_parse.c: Likewise. * resolv/ns_print.c: Likewise. * resolv/ns_samedomain.c: Likewise. * resolv/ns_ttl.c: Likewise. * resolv/arpa/nameser_compat.h: Likewise. * resolv/res_debug.h: Likewise. Some patches are based on work done by Adam D. Bradley <artdodge@cs.bu.edu>. * sysdeps/unix/sysv/linux/configure.in: Remove check for ldconfig, set always use_ldconfig instead.
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#include <string.h>
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#include <sys/time.h>
#include <shlib-compat.h>
#include <random-bits.h>
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int
__res_context_mkquery (struct resolv_context *ctx, int op, const char *dname,
int class, int type, const unsigned char *data,
unsigned char *buf, int buflen)
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{
UHEADER *hp;
unsigned char *cp;
int n;
unsigned char *dnptrs[20], **dpp, **lastdnptr;
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if (class < 0 || class > 65535 || type < 0 || type > 65535)
return -1;
/* Initialize header fields. */
if ((buf == NULL) || (buflen < HFIXEDSZ))
return -1;
memset (buf, 0, HFIXEDSZ);
hp = (UHEADER *) buf;
/* We randomize the IDs every time. The old code just incremented
by one after the initial randomization which still predictable if
the application does multiple requests. */
hp->id = random_bits ();
hp->opcode = op;
if (ctx->resp->options & RES_TRUSTAD)
hp->ad = 1;
hp->rd = (ctx->resp->options & RES_RECURSE) != 0;
hp->rcode = NOERROR;
cp = buf + HFIXEDSZ;
buflen -= HFIXEDSZ;
dpp = dnptrs;
*dpp++ = buf;
*dpp++ = NULL;
lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];
/* Perform opcode specific processing. */
switch (op)
{
case NS_NOTIFY_OP:
if ((buflen -= QFIXEDSZ + (data == NULL ? 0 : RRFIXEDSZ)) < 0)
return -1;
goto compose;
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case QUERY:
if ((buflen -= QFIXEDSZ) < 0)
return -1;
compose:
n = __ns_name_compress (dname, cp, buflen,
(const unsigned char **) dnptrs,
(const unsigned char **) lastdnptr);
if (n < 0)
return -1;
cp += n;
buflen -= n;
NS_PUT16 (type, cp);
NS_PUT16 (class, cp);
hp->qdcount = htons (1);
if (op == QUERY || data == NULL)
break;
/* Make an additional record for completion domain. */
n = __ns_name_compress ((char *)data, cp, buflen,
(const unsigned char **) dnptrs,
(const unsigned char **) lastdnptr);
if (__glibc_unlikely (n < 0))
return -1;
cp += n;
buflen -= n;
NS_PUT16 (T_NULL, cp);
NS_PUT16 (class, cp);
NS_PUT32 (0, cp);
NS_PUT16 (0, cp);
hp->arcount = htons (1);
break;
default:
return -1;
}
return cp - buf;
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}
libc_hidden_def (__res_context_mkquery)
/* Common part of res_nmkquery and res_mkquery. */
static int
context_mkquery_common (struct resolv_context *ctx,
int op, const char *dname, int class, int type,
const unsigned char *data,
unsigned char *buf, int buflen)
{
if (ctx == NULL)
return -1;
int result = __res_context_mkquery
(ctx, op, dname, class, type, data, buf, buflen);
if (result >= 2)
memcpy (&ctx->resp->id, buf, 2);
__resolv_context_put (ctx);
return result;
}
/* Form all types of queries. Returns the size of the result or -1 on
error.
STATP points to an initialized resolver state. OP is the opcode of
the query. DNAME is the domain. CLASS and TYPE are the DNS query
class and type. DATA can be NULL; otherwise, it is a pointer to a
domain name which is included in the generated packet (if op ==
NS_NOTIFY_OP). BUF must point to the out buffer of BUFLEN bytes.
DATALEN and NEWRR_IN are currently ignored. */
int
___res_nmkquery (res_state statp, int op, const char *dname,
int class, int type,
const unsigned char *data, int datalen,
const unsigned char *newrr_in,
unsigned char *buf, int buflen)
{
return context_mkquery_common
(__resolv_context_get_override (statp),
op, dname, class, type, data, buf, buflen);
}
versioned_symbol (libc, ___res_nmkquery, res_nmkquery, GLIBC_2_34);
#if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_2, GLIBC_2_34)
compat_symbol (libresolv, ___res_nmkquery, __res_nmkquery, GLIBC_2_2);
#endif
int
___res_mkquery (int op, const char *dname, int class, int type,
const unsigned char *data, int datalen,
const unsigned char *newrr_in,
unsigned char *buf, int buflen)
{
return context_mkquery_common
(__resolv_context_get_preinit (),
op, dname, class, type, data, buf, buflen);
}
versioned_symbol (libc, ___res_mkquery, res_mkquery, GLIBC_2_34);
#if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_0, GLIBC_2_2)
compat_symbol (libresolv, ___res_mkquery, res_mkquery, GLIBC_2_0);
#endif
#if OTHER_SHLIB_COMPAT (libresolv, GLIBC_2_2, GLIBC_2_34)
compat_symbol (libresolv, ___res_mkquery, __res_mkquery, GLIBC_2_2);
#endif
/* Create an OPT resource record. Return the length of the final
packet, or -1 on error.
STATP must be an initialized resolver state. N0 is the current
number of bytes of the packet (already written to BUF by the
aller). BUF is the packet being constructed. The array it
pointers to must be BUFLEN bytes long. ANSLEN is the advertised
EDNS buffer size (to be included in the OPT resource record). */
int
__res_nopt (struct resolv_context *ctx,
int n0, unsigned char *buf, int buflen, int anslen)
{
uint16_t flags = 0;
UHEADER *hp = (UHEADER *) buf;
unsigned char *cp = buf + n0;
unsigned char *ep = buf + buflen;
if ((ep - cp) < 1 + RRFIXEDSZ)
return -1;
/* Add the root label. */
*cp++ = 0;
NS_PUT16 (T_OPT, cp); /* Record type. */
/* Lowering the advertised buffer size based on the actual
answer buffer size is desirable because the server will
minimize the reply to fit into the UDP packet (and A
non-minimal response might not fit the buffer).
The RESOLV_EDNS_BUFFER_SIZE limit could still result in TCP
fallback and a non-minimal response which has to be
hard-truncated in the stub resolver, but this is price to
pay for avoiding fragmentation. (This issue does not
affect the nss_dns functions because they use the stub
resolver in such a way that it allocates a properly sized
response buffer.) */
{
uint16_t buffer_size;
if (anslen < 512)
buffer_size = 512;
else if (anslen > RESOLV_EDNS_BUFFER_SIZE)
buffer_size = RESOLV_EDNS_BUFFER_SIZE;
else
buffer_size = anslen;
NS_PUT16 (buffer_size, cp);
}
*cp++ = NOERROR; /* Extended RCODE. */
*cp++ = 0; /* EDNS version. */
if (ctx->resp->options & RES_USE_DNSSEC)
flags |= NS_OPT_DNSSEC_OK;
NS_PUT16 (flags, cp);
NS_PUT16 (0, cp); /* RDATA length (no options are preent). */
hp->arcount = htons (ntohs (hp->arcount) + 1);
return cp - buf;
}
libc_hidden_def (__res_nopt)