275 lines
7 KiB
C
275 lines
7 KiB
C
/* $NetBSD: ns_parse.c,v 1.9 2012/03/13 21:13:39 christos Exp $ */
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/*
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* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
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* Copyright (c) 1996,1999 by Internet Software Consortium.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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* OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <sys/cdefs.h>
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#ifndef lint
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#ifdef notdef
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static const char rcsid[] = "Id: ns_parse.c,v 1.10 2009/01/23 19:59:16 each Exp";
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#else
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__RCSID("$NetBSD: ns_parse.c,v 1.9 2012/03/13 21:13:39 christos Exp $");
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#endif
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#endif
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/* Import. */
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#include <sys/types.h>
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#include <netinet/in.h>
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#include <arpa/nameser.h>
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#include <assert.h>
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#include <errno.h>
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#ifdef ANDROID_CHANGES
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#include "resolv_private.h"
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#else
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#include <resolv.h>
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#endif
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#include <string.h>
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/* Forward. */
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static void setsection(ns_msg *msg, ns_sect sect);
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/* Macros. */
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#define RETERR(err) do { errno = (err); return (-1); } while (/*NOTREACHED*//*CONSTCOND*/0)
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/* Public. */
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/* These need to be in the same order as the nres.h:ns_flag enum. */
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const struct _ns_flagdata _ns_flagdata[16] = {
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{ 0x8000, 15 }, /* qr. */
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{ 0x7800, 11 }, /* opcode. */
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{ 0x0400, 10 }, /* aa. */
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{ 0x0200, 9 }, /* tc. */
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{ 0x0100, 8 }, /* rd. */
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{ 0x0080, 7 }, /* ra. */
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{ 0x0040, 6 }, /* z. */
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{ 0x0020, 5 }, /* ad. */
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{ 0x0010, 4 }, /* cd. */
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{ 0x000f, 0 }, /* rcode. */
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{ 0x0000, 0 }, /* expansion (1/6). */
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{ 0x0000, 0 }, /* expansion (2/6). */
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{ 0x0000, 0 }, /* expansion (3/6). */
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{ 0x0000, 0 }, /* expansion (4/6). */
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{ 0x0000, 0 }, /* expansion (5/6). */
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{ 0x0000, 0 }, /* expansion (6/6). */
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};
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int ns_msg_getflag(ns_msg handle, int flag) {
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return((u_int32_t)((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);
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}
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int
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ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
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const u_char *optr = ptr;
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for (; count > 0; count--) {
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int b, rdlength;
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b = dn_skipname(ptr, eom);
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if (b < 0)
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RETERR(EMSGSIZE);
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ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
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if (section != ns_s_qd) {
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if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
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RETERR(EMSGSIZE);
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ptr += NS_INT32SZ/*TTL*/;
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NS_GET16(rdlength, ptr);
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ptr += rdlength/*RData*/;
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}
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}
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if (ptr > eom)
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RETERR(EMSGSIZE);
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_DIAGASSERT(__type_fit(int, ptr - optr));
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return (int)(ptr - optr);
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}
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int
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ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
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const u_char *eom = msg + msglen;
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int i;
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handle->_msg = msg;
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handle->_eom = eom;
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if (msg + NS_INT16SZ > eom)
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RETERR(EMSGSIZE);
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NS_GET16(handle->_id, msg);
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if (msg + NS_INT16SZ > eom)
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RETERR(EMSGSIZE);
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NS_GET16(handle->_flags, msg);
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for (i = 0; i < ns_s_max; i++) {
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if (msg + NS_INT16SZ > eom)
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RETERR(EMSGSIZE);
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NS_GET16(handle->_counts[i], msg);
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}
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for (i = 0; i < ns_s_max; i++)
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if (handle->_counts[i] == 0)
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handle->_sections[i] = NULL;
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else {
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int b = ns_skiprr(msg, eom, (ns_sect)i,
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handle->_counts[i]);
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if (b < 0)
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return (-1);
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handle->_sections[i] = msg;
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msg += b;
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}
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if (msg != eom)
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RETERR(EMSGSIZE);
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setsection(handle, ns_s_max);
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return (0);
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}
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int
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ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
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int b;
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int tmp;
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/* Make section right. */
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tmp = section;
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if (tmp < 0 || section >= ns_s_max)
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RETERR(ENODEV);
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if (section != handle->_sect)
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setsection(handle, section);
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/* Make rrnum right. */
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if (rrnum == -1)
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rrnum = handle->_rrnum;
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if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
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RETERR(ENODEV);
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if (rrnum < handle->_rrnum)
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setsection(handle, section);
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if (rrnum > handle->_rrnum) {
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b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
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rrnum - handle->_rrnum);
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if (b < 0)
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return (-1);
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handle->_msg_ptr += b;
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handle->_rrnum = rrnum;
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}
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/* Do the parse. */
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b = dn_expand(handle->_msg, handle->_eom,
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handle->_msg_ptr, rr->name, NS_MAXDNAME);
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if (b < 0)
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return (-1);
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handle->_msg_ptr += b;
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if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
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RETERR(EMSGSIZE);
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NS_GET16(rr->type, handle->_msg_ptr);
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NS_GET16(rr->rr_class, handle->_msg_ptr);
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if (section == ns_s_qd) {
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rr->ttl = 0;
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rr->rdlength = 0;
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rr->rdata = NULL;
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} else {
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if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
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RETERR(EMSGSIZE);
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NS_GET32(rr->ttl, handle->_msg_ptr);
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NS_GET16(rr->rdlength, handle->_msg_ptr);
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if (handle->_msg_ptr + rr->rdlength > handle->_eom)
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RETERR(EMSGSIZE);
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rr->rdata = handle->_msg_ptr;
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handle->_msg_ptr += rr->rdlength;
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}
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if (++handle->_rrnum > handle->_counts[(int)section])
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setsection(handle, (ns_sect)((int)section + 1));
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/* All done. */
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return (0);
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}
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/*
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* This is identical to the above but uses network-format (uncompressed) names.
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*/
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int
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ns_parserr2(ns_msg *handle, ns_sect section, int rrnum, ns_rr2 *rr) {
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int b;
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int tmp;
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/* Make section right. */
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tmp = section;
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if (tmp < 0 || section >= ns_s_max)
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RETERR(ENODEV);
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if (section != handle->_sect)
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setsection(handle, section);
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/* Make rrnum right. */
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if (rrnum == -1)
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rrnum = handle->_rrnum;
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if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
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RETERR(ENODEV);
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if (rrnum < handle->_rrnum)
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setsection(handle, section);
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if (rrnum > handle->_rrnum) {
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b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
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rrnum - handle->_rrnum);
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if (b < 0)
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return (-1);
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handle->_msg_ptr += b;
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handle->_rrnum = rrnum;
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}
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/* Do the parse. */
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b = ns_name_unpack2(handle->_msg, handle->_eom, handle->_msg_ptr,
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rr->nname, NS_MAXNNAME, &rr->nnamel);
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if (b < 0)
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return (-1);
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handle->_msg_ptr += b;
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if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
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RETERR(EMSGSIZE);
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NS_GET16(rr->type, handle->_msg_ptr);
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NS_GET16(rr->rr_class, handle->_msg_ptr);
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if (section == ns_s_qd) {
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rr->ttl = 0;
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rr->rdlength = 0;
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rr->rdata = NULL;
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} else {
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if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
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RETERR(EMSGSIZE);
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NS_GET32(rr->ttl, handle->_msg_ptr);
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NS_GET16(rr->rdlength, handle->_msg_ptr);
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if (handle->_msg_ptr + rr->rdlength > handle->_eom)
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RETERR(EMSGSIZE);
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rr->rdata = handle->_msg_ptr;
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handle->_msg_ptr += rr->rdlength;
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}
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if (++handle->_rrnum > handle->_counts[(int)section])
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setsection(handle, (ns_sect)((int)section + 1));
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/* All done. */
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return (0);
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}
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/* Private. */
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static void
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setsection(ns_msg *msg, ns_sect sect) {
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msg->_sect = sect;
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if (sect == ns_s_max) {
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msg->_rrnum = -1;
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msg->_msg_ptr = NULL;
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} else {
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msg->_rrnum = 0;
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msg->_msg_ptr = msg->_sections[(int)sect];
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}
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}
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