/* $NetBSD: ns_parse.c,v 1.9 2012/03/13 21:13:39 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.
*/
#include <sys/cdefs.h>
#ifndef lint
#ifdef notdef
static const char rcsid[] = "Id: ns_parse.c,v 1.10 2009/01/23 19:59:16 each Exp";
#else
__RCSID("$NetBSD: ns_parse.c,v 1.9 2012/03/13 21:13:39 christos Exp $");
#endif
#endif
/* Import. */
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <assert.h>
#include <errno.h>
#ifdef ANDROID_CHANGES
#include "resolv_private.h"
#else
#include <resolv.h>
#endif
#include <string.h>
/* Forward. */
static void setsection(ns_msg *msg, ns_sect sect);
/* Macros. */
#define RETERR(err) do { errno = (err); return (-1); } while (/*NOTREACHED*//*CONSTCOND*/0)
/* Public. */
struct _ns_flagdata { int mask, shift; };
/* These need to be in the same order as the nres.h:ns_flag enum. */
const 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((u_int32_t)((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 (; 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);
_DIAGASSERT(__type_fit(int, ptr - optr));
return (int)(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. */
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 = 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];
}
}