/*      $NetBSD: ns_parse.c,v 1.1.1.2 2012/09/09 16:08:05 christos Exp $        */

/*
* Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
* 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 ISC DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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.
*/

#ifndef lint
static const char rcsid[] = "Id: ns_parse.c,v 1.10 2009/01/23 19:59:16 each Exp ";
#endif

/* Import. */

#include "port_before.h"

#include <sys/types.h>

#include <netinet/in.h>
#include <arpa/nameser.h>

#include <errno.h>
#include <resolv.h>
#include <string.h>

#include "port_after.h"

/* Forward. */

static void     setsection(ns_msg *msg, ns_sect sect);

/* Macros. */

#if !defined(SOLARIS2) || defined(__COVERITY__)
#define RETERR(err) do { errno = (err); return (-1); } while (0)
#else
#define RETERR(err) \
       do { errno = (err); if (errno == errno) return (-1); } while (0)
#endif

#define PARSE_FMT_PRESO 0       /* Parse using presentation-format names */
#define PARSE_FMT_WIRE 1        /* Parse using network-format names */

/* Public. */

/* These need to be in the same order as the nres.h:ns_flag enum. */
struct _ns_flagdata _ns_flagdata[16] = {
       { 0x8000, 15 },         /*%< qr. */
       { 0x7800, 11 },         /*%< opcode. */
       { 0x0400, 10 },         /*%< aa. */
       { 0x0200, 9 },          /*%< tc. */
       { 0x0100, 8 },          /*%< rd. */
       { 0x0080, 7 },          /*%< ra. */
       { 0x0040, 6 },          /*%< z. */
       { 0x0020, 5 },          /*%< ad. */
       { 0x0010, 4 },          /*%< cd. */
       { 0x000f, 0 },          /*%< rcode. */
       { 0x0000, 0 },          /*%< expansion (1/6). */
       { 0x0000, 0 },          /*%< expansion (2/6). */
       { 0x0000, 0 },          /*%< expansion (3/6). */
       { 0x0000, 0 },          /*%< expansion (4/6). */
       { 0x0000, 0 },          /*%< expansion (5/6). */
       { 0x0000, 0 },          /*%< expansion (6/6). */
};

int ns_msg_getflag(ns_msg handle, int flag) {
       return(((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);
}

int
ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
       const u_char *optr = ptr;

       for ((void)NULL; count > 0; count--) {
               int b, rdlength;

               b = dn_skipname(ptr, eom);
               if (b < 0)
                       RETERR(EMSGSIZE);
               ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
               if (section != ns_s_qd) {
                       if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
                               RETERR(EMSGSIZE);
                       ptr += NS_INT32SZ/*TTL*/;
                       NS_GET16(rdlength, ptr);
                       ptr += rdlength/*RData*/;
               }
       }
       if (ptr > eom)
               RETERR(EMSGSIZE);
       return (ptr - optr);
}

int
ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
       const u_char *eom = msg + msglen;
       int i;

       handle->_msg = msg;
       handle->_eom = eom;
       if (msg + NS_INT16SZ > eom)
               RETERR(EMSGSIZE);
       NS_GET16(handle->_id, msg);
       if (msg + NS_INT16SZ > eom)
               RETERR(EMSGSIZE);
       NS_GET16(handle->_flags, msg);
       for (i = 0; i < ns_s_max; i++) {
               if (msg + NS_INT16SZ > eom)
                       RETERR(EMSGSIZE);
               NS_GET16(handle->_counts[i], msg);
       }
       for (i = 0; i < ns_s_max; i++)
               if (handle->_counts[i] == 0)
                       handle->_sections[i] = NULL;
               else {
                       int b = ns_skiprr(msg, eom, (ns_sect)i,
                                         handle->_counts[i]);

                       if (b < 0)
                               return (-1);
                       handle->_sections[i] = msg;
                       msg += b;
               }
       if (msg != eom)
               RETERR(EMSGSIZE);
       setsection(handle, ns_s_max);
       return (0);
}

int
ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
       int b;
       int tmp;

       /* Make section right. */
       tmp = section;
       if (tmp < 0 || section >= ns_s_max)
               RETERR(ENODEV);
       if (section != handle->_sect)
               setsection(handle, section);

       /* Make rrnum right. */
       if (rrnum == -1)
               rrnum = handle->_rrnum;
       if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
               RETERR(ENODEV);
       if (rrnum < handle->_rrnum)
               setsection(handle, section);
       if (rrnum > handle->_rrnum) {
               b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
                             rrnum - handle->_rrnum);

               if (b < 0)
                       return (-1);
               handle->_msg_ptr += b;
               handle->_rrnum = rrnum;
       }

       /* Do the parse. */
       b = dn_expand(handle->_msg, handle->_eom,
                     handle->_msg_ptr, rr->name, NS_MAXDNAME);
       if (b < 0)
               return (-1);
       handle->_msg_ptr += b;
       if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
               RETERR(EMSGSIZE);
       NS_GET16(rr->type, handle->_msg_ptr);
       NS_GET16(rr->rr_class, handle->_msg_ptr);
       if (section == ns_s_qd) {
               rr->ttl = 0;
               rr->rdlength = 0;
               rr->rdata = NULL;
       } else {
               if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
                       RETERR(EMSGSIZE);
               NS_GET32(rr->ttl, handle->_msg_ptr);
               NS_GET16(rr->rdlength, handle->_msg_ptr);
               if (handle->_msg_ptr + rr->rdlength > handle->_eom)
                       RETERR(EMSGSIZE);
               rr->rdata = handle->_msg_ptr;
               handle->_msg_ptr += rr->rdlength;
       }
       if (++handle->_rrnum > handle->_counts[(int)section])
               setsection(handle, (ns_sect)((int)section + 1));

       /* All done. */
       return (0);
}

/*
* This is identical to the above but uses network-format (uncompressed) names.
*/
int
ns_parserr2(ns_msg *handle, ns_sect section, int rrnum, ns_rr2 *rr) {
       int b;
       int tmp;

       /* Make section right. */
       if ((tmp = section) < 0 || section >= ns_s_max)
               RETERR(ENODEV);
       if (section != handle->_sect)
               setsection(handle, section);

       /* Make rrnum right. */
       if (rrnum == -1)
               rrnum = handle->_rrnum;
       if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
               RETERR(ENODEV);
       if (rrnum < handle->_rrnum)
               setsection(handle, section);
       if (rrnum > handle->_rrnum) {
               b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
                             rrnum - handle->_rrnum);

               if (b < 0)
                       return (-1);
               handle->_msg_ptr += b;
               handle->_rrnum = rrnum;
       }

       /* Do the parse. */
       b = ns_name_unpack2(handle->_msg, handle->_eom, handle->_msg_ptr,
                           rr->nname, NS_MAXNNAME, &rr->nnamel);
       if (b < 0)
               return (-1);
       handle->_msg_ptr += b;
       if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
               RETERR(EMSGSIZE);
       NS_GET16(rr->type, handle->_msg_ptr);
       NS_GET16(rr->rr_class, handle->_msg_ptr);
       if (section == ns_s_qd) {
               rr->ttl = 0;
               rr->rdlength = 0;
               rr->rdata = NULL;
       } else {
               if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
                       RETERR(EMSGSIZE);
               NS_GET32(rr->ttl, handle->_msg_ptr);
               NS_GET16(rr->rdlength, handle->_msg_ptr);
               if (handle->_msg_ptr + rr->rdlength > handle->_eom)
                       RETERR(EMSGSIZE);
               rr->rdata = handle->_msg_ptr;
               handle->_msg_ptr += rr->rdlength;
       }
       if (++handle->_rrnum > handle->_counts[(int)section])
               setsection(handle, (ns_sect)((int)section + 1));

       /* All done. */
       return (0);
}

/* Private. */

static void
setsection(ns_msg *msg, ns_sect sect) {
       msg->_sect = sect;
       if (sect == ns_s_max) {
               msg->_rrnum = -1;
               msg->_msg_ptr = NULL;
       } else {
               msg->_rrnum = 0;
               msg->_msg_ptr = msg->_sections[(int)sect];
       }
}

/*! \file */

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