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ns_parse.c revision 1.7
      1  1.7  christos /*	$NetBSD: ns_parse.c,v 1.7 2009/04/12 17:07:17 christos Exp $	*/
      2  1.1  christos 
      3  1.1  christos /*
      4  1.1  christos  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
      5  1.1  christos  * Copyright (c) 1996,1999 by Internet Software Consortium.
      6  1.1  christos  *
      7  1.1  christos  * Permission to use, copy, modify, and distribute this software for any
      8  1.1  christos  * purpose with or without fee is hereby granted, provided that the above
      9  1.1  christos  * copyright notice and this permission notice appear in all copies.
     10  1.1  christos  *
     11  1.1  christos  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
     12  1.1  christos  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     13  1.1  christos  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
     14  1.1  christos  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     15  1.1  christos  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     16  1.1  christos  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
     17  1.1  christos  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     18  1.1  christos  */
     19  1.1  christos 
     20  1.2  christos #include <sys/cdefs.h>
     21  1.1  christos #ifndef lint
     22  1.2  christos #ifdef notdef
     23  1.7  christos static const char rcsid[] = "Id: ns_parse.c,v 1.10 2009/01/23 19:59:16 each Exp";
     24  1.2  christos #else
     25  1.7  christos __RCSID("$NetBSD: ns_parse.c,v 1.7 2009/04/12 17:07:17 christos Exp $");
     26  1.2  christos #endif
     27  1.1  christos #endif
     28  1.1  christos 
     29  1.1  christos /* Import. */
     30  1.1  christos 
     31  1.1  christos #include "port_before.h"
     32  1.1  christos 
     33  1.1  christos #include <sys/types.h>
     34  1.1  christos 
     35  1.1  christos #include <netinet/in.h>
     36  1.1  christos #include <arpa/nameser.h>
     37  1.1  christos 
     38  1.1  christos #include <errno.h>
     39  1.1  christos #include <resolv.h>
     40  1.1  christos #include <string.h>
     41  1.1  christos 
     42  1.1  christos #include "port_after.h"
     43  1.1  christos 
     44  1.1  christos /* Forward. */
     45  1.1  christos 
     46  1.1  christos static void	setsection(ns_msg *msg, ns_sect sect);
     47  1.1  christos 
     48  1.1  christos /* Macros. */
     49  1.1  christos 
     50  1.6  christos #if !defined(SOLARIS2) || defined(__COVERITY__)
     51  1.2  christos #define RETERR(err) do { errno = (err); return (-1); } while (/*NOTREACHED*//*CONSTCOND*/0)
     52  1.4  christos #else
     53  1.4  christos #define RETERR(err) \
     54  1.4  christos 	do { errno = (err); if (errno == errno) return (-1); } while (0)
     55  1.4  christos #endif
     56  1.1  christos 
     57  1.7  christos #define PARSE_FMT_PRESO 0	/* Parse using presentation-format names */
     58  1.7  christos #define PARSE_FMT_WIRE 1	/* Parse using network-format names */
     59  1.7  christos 
     60  1.1  christos /* Public. */
     61  1.1  christos 
     62  1.1  christos /* These need to be in the same order as the nres.h:ns_flag enum. */
     63  1.1  christos struct _ns_flagdata _ns_flagdata[16] = {
     64  1.4  christos 	{ 0x8000, 15 },		/*%< qr. */
     65  1.4  christos 	{ 0x7800, 11 },		/*%< opcode. */
     66  1.4  christos 	{ 0x0400, 10 },		/*%< aa. */
     67  1.4  christos 	{ 0x0200, 9 },		/*%< tc. */
     68  1.4  christos 	{ 0x0100, 8 },		/*%< rd. */
     69  1.4  christos 	{ 0x0080, 7 },		/*%< ra. */
     70  1.4  christos 	{ 0x0040, 6 },		/*%< z. */
     71  1.4  christos 	{ 0x0020, 5 },		/*%< ad. */
     72  1.4  christos 	{ 0x0010, 4 },		/*%< cd. */
     73  1.4  christos 	{ 0x000f, 0 },		/*%< rcode. */
     74  1.4  christos 	{ 0x0000, 0 },		/*%< expansion (1/6). */
     75  1.4  christos 	{ 0x0000, 0 },		/*%< expansion (2/6). */
     76  1.4  christos 	{ 0x0000, 0 },		/*%< expansion (3/6). */
     77  1.4  christos 	{ 0x0000, 0 },		/*%< expansion (4/6). */
     78  1.4  christos 	{ 0x0000, 0 },		/*%< expansion (5/6). */
     79  1.4  christos 	{ 0x0000, 0 },		/*%< expansion (6/6). */
     80  1.1  christos };
     81  1.1  christos 
     82  1.1  christos int ns_msg_getflag(ns_msg handle, int flag) {
     83  1.2  christos 	return((u_int32_t)((handle)._flags & _ns_flagdata[flag].mask) >> _ns_flagdata[flag].shift);
     84  1.1  christos }
     85  1.1  christos 
     86  1.1  christos int
     87  1.1  christos ns_skiprr(const u_char *ptr, const u_char *eom, ns_sect section, int count) {
     88  1.1  christos 	const u_char *optr = ptr;
     89  1.1  christos 
     90  1.2  christos 	for (; count > 0; count--) {
     91  1.1  christos 		int b, rdlength;
     92  1.1  christos 
     93  1.1  christos 		b = dn_skipname(ptr, eom);
     94  1.1  christos 		if (b < 0)
     95  1.1  christos 			RETERR(EMSGSIZE);
     96  1.1  christos 		ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
     97  1.1  christos 		if (section != ns_s_qd) {
     98  1.1  christos 			if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
     99  1.1  christos 				RETERR(EMSGSIZE);
    100  1.1  christos 			ptr += NS_INT32SZ/*TTL*/;
    101  1.1  christos 			NS_GET16(rdlength, ptr);
    102  1.1  christos 			ptr += rdlength/*RData*/;
    103  1.1  christos 		}
    104  1.1  christos 	}
    105  1.1  christos 	if (ptr > eom)
    106  1.1  christos 		RETERR(EMSGSIZE);
    107  1.1  christos 	return (ptr - optr);
    108  1.1  christos }
    109  1.1  christos 
    110  1.1  christos int
    111  1.1  christos ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
    112  1.1  christos 	const u_char *eom = msg + msglen;
    113  1.1  christos 	int i;
    114  1.1  christos 
    115  1.1  christos 	handle->_msg = msg;
    116  1.1  christos 	handle->_eom = eom;
    117  1.1  christos 	if (msg + NS_INT16SZ > eom)
    118  1.1  christos 		RETERR(EMSGSIZE);
    119  1.1  christos 	NS_GET16(handle->_id, msg);
    120  1.1  christos 	if (msg + NS_INT16SZ > eom)
    121  1.1  christos 		RETERR(EMSGSIZE);
    122  1.1  christos 	NS_GET16(handle->_flags, msg);
    123  1.1  christos 	for (i = 0; i < ns_s_max; i++) {
    124  1.1  christos 		if (msg + NS_INT16SZ > eom)
    125  1.1  christos 			RETERR(EMSGSIZE);
    126  1.1  christos 		NS_GET16(handle->_counts[i], msg);
    127  1.1  christos 	}
    128  1.1  christos 	for (i = 0; i < ns_s_max; i++)
    129  1.1  christos 		if (handle->_counts[i] == 0)
    130  1.1  christos 			handle->_sections[i] = NULL;
    131  1.1  christos 		else {
    132  1.1  christos 			int b = ns_skiprr(msg, eom, (ns_sect)i,
    133  1.1  christos 					  handle->_counts[i]);
    134  1.1  christos 
    135  1.1  christos 			if (b < 0)
    136  1.1  christos 				return (-1);
    137  1.1  christos 			handle->_sections[i] = msg;
    138  1.1  christos 			msg += b;
    139  1.1  christos 		}
    140  1.1  christos 	if (msg != eom)
    141  1.1  christos 		RETERR(EMSGSIZE);
    142  1.1  christos 	setsection(handle, ns_s_max);
    143  1.1  christos 	return (0);
    144  1.1  christos }
    145  1.1  christos 
    146  1.1  christos int
    147  1.1  christos ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
    148  1.1  christos 	int b;
    149  1.4  christos 	int tmp;
    150  1.1  christos 
    151  1.1  christos 	/* Make section right. */
    152  1.4  christos 	tmp = section;
    153  1.4  christos 	if (tmp < 0 || section >= ns_s_max)
    154  1.1  christos 		RETERR(ENODEV);
    155  1.1  christos 	if (section != handle->_sect)
    156  1.1  christos 		setsection(handle, section);
    157  1.1  christos 
    158  1.1  christos 	/* Make rrnum right. */
    159  1.1  christos 	if (rrnum == -1)
    160  1.1  christos 		rrnum = handle->_rrnum;
    161  1.1  christos 	if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
    162  1.1  christos 		RETERR(ENODEV);
    163  1.1  christos 	if (rrnum < handle->_rrnum)
    164  1.1  christos 		setsection(handle, section);
    165  1.1  christos 	if (rrnum > handle->_rrnum) {
    166  1.1  christos 		b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
    167  1.1  christos 			      rrnum - handle->_rrnum);
    168  1.1  christos 
    169  1.1  christos 		if (b < 0)
    170  1.1  christos 			return (-1);
    171  1.1  christos 		handle->_msg_ptr += b;
    172  1.1  christos 		handle->_rrnum = rrnum;
    173  1.1  christos 	}
    174  1.1  christos 
    175  1.1  christos 	/* Do the parse. */
    176  1.1  christos 	b = dn_expand(handle->_msg, handle->_eom,
    177  1.1  christos 		      handle->_msg_ptr, rr->name, NS_MAXDNAME);
    178  1.1  christos 	if (b < 0)
    179  1.1  christos 		return (-1);
    180  1.1  christos 	handle->_msg_ptr += b;
    181  1.1  christos 	if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
    182  1.1  christos 		RETERR(EMSGSIZE);
    183  1.1  christos 	NS_GET16(rr->type, handle->_msg_ptr);
    184  1.1  christos 	NS_GET16(rr->rr_class, handle->_msg_ptr);
    185  1.1  christos 	if (section == ns_s_qd) {
    186  1.1  christos 		rr->ttl = 0;
    187  1.1  christos 		rr->rdlength = 0;
    188  1.1  christos 		rr->rdata = NULL;
    189  1.1  christos 	} else {
    190  1.1  christos 		if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
    191  1.1  christos 			RETERR(EMSGSIZE);
    192  1.1  christos 		NS_GET32(rr->ttl, handle->_msg_ptr);
    193  1.1  christos 		NS_GET16(rr->rdlength, handle->_msg_ptr);
    194  1.1  christos 		if (handle->_msg_ptr + rr->rdlength > handle->_eom)
    195  1.1  christos 			RETERR(EMSGSIZE);
    196  1.1  christos 		rr->rdata = handle->_msg_ptr;
    197  1.1  christos 		handle->_msg_ptr += rr->rdlength;
    198  1.1  christos 	}
    199  1.1  christos 	if (++handle->_rrnum > handle->_counts[(int)section])
    200  1.1  christos 		setsection(handle, (ns_sect)((int)section + 1));
    201  1.1  christos 
    202  1.1  christos 	/* All done. */
    203  1.1  christos 	return (0);
    204  1.1  christos }
    205  1.1  christos 
    206  1.7  christos /*
    207  1.7  christos  * This is identical to the above but uses network-format (uncompressed) names.
    208  1.7  christos  */
    209  1.7  christos int
    210  1.7  christos ns_parserr2(ns_msg *handle, ns_sect section, int rrnum, ns_rr2 *rr) {
    211  1.7  christos 	int b;
    212  1.7  christos 	int tmp;
    213  1.7  christos 
    214  1.7  christos 	/* Make section right. */
    215  1.7  christos 	if ((tmp = section) < 0 || section >= ns_s_max)
    216  1.7  christos 		RETERR(ENODEV);
    217  1.7  christos 	if (section != handle->_sect)
    218  1.7  christos 		setsection(handle, section);
    219  1.7  christos 
    220  1.7  christos 	/* Make rrnum right. */
    221  1.7  christos 	if (rrnum == -1)
    222  1.7  christos 		rrnum = handle->_rrnum;
    223  1.7  christos 	if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
    224  1.7  christos 		RETERR(ENODEV);
    225  1.7  christos 	if (rrnum < handle->_rrnum)
    226  1.7  christos 		setsection(handle, section);
    227  1.7  christos 	if (rrnum > handle->_rrnum) {
    228  1.7  christos 		b = ns_skiprr(handle->_msg_ptr, handle->_eom, section,
    229  1.7  christos 			      rrnum - handle->_rrnum);
    230  1.7  christos 
    231  1.7  christos 		if (b < 0)
    232  1.7  christos 			return (-1);
    233  1.7  christos 		handle->_msg_ptr += b;
    234  1.7  christos 		handle->_rrnum = rrnum;
    235  1.7  christos 	}
    236  1.7  christos 
    237  1.7  christos 	/* Do the parse. */
    238  1.7  christos 	b = ns_name_unpack2(handle->_msg, handle->_eom, handle->_msg_ptr,
    239  1.7  christos 			    rr->nname, NS_MAXNNAME, &rr->nnamel);
    240  1.7  christos 	if (b < 0)
    241  1.7  christos 		return (-1);
    242  1.7  christos 	handle->_msg_ptr += b;
    243  1.7  christos 	if (handle->_msg_ptr + NS_INT16SZ + NS_INT16SZ > handle->_eom)
    244  1.7  christos 		RETERR(EMSGSIZE);
    245  1.7  christos 	NS_GET16(rr->type, handle->_msg_ptr);
    246  1.7  christos 	NS_GET16(rr->rr_class, handle->_msg_ptr);
    247  1.7  christos 	if (section == ns_s_qd) {
    248  1.7  christos 		rr->ttl = 0;
    249  1.7  christos 		rr->rdlength = 0;
    250  1.7  christos 		rr->rdata = NULL;
    251  1.7  christos 	} else {
    252  1.7  christos 		if (handle->_msg_ptr + NS_INT32SZ + NS_INT16SZ > handle->_eom)
    253  1.7  christos 			RETERR(EMSGSIZE);
    254  1.7  christos 		NS_GET32(rr->ttl, handle->_msg_ptr);
    255  1.7  christos 		NS_GET16(rr->rdlength, handle->_msg_ptr);
    256  1.7  christos 		if (handle->_msg_ptr + rr->rdlength > handle->_eom)
    257  1.7  christos 			RETERR(EMSGSIZE);
    258  1.7  christos 		rr->rdata = handle->_msg_ptr;
    259  1.7  christos 		handle->_msg_ptr += rr->rdlength;
    260  1.7  christos 	}
    261  1.7  christos 	if (++handle->_rrnum > handle->_counts[(int)section])
    262  1.7  christos 		setsection(handle, (ns_sect)((int)section + 1));
    263  1.7  christos 
    264  1.7  christos 	/* All done. */
    265  1.7  christos 	return (0);
    266  1.7  christos }
    267  1.7  christos 
    268  1.1  christos /* Private. */
    269  1.1  christos 
    270  1.1  christos static void
    271  1.1  christos setsection(ns_msg *msg, ns_sect sect) {
    272  1.1  christos 	msg->_sect = sect;
    273  1.1  christos 	if (sect == ns_s_max) {
    274  1.1  christos 		msg->_rrnum = -1;
    275  1.1  christos 		msg->_msg_ptr = NULL;
    276  1.1  christos 	} else {
    277  1.1  christos 		msg->_rrnum = 0;
    278  1.1  christos 		msg->_msg_ptr = msg->_sections[(int)sect];
    279  1.1  christos 	}
    280  1.1  christos }
    281  1.4  christos 
    282  1.4  christos /*! \file */
    283