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/*
* Copyright (c) 1996 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <errno.h>
#include <resolv.h>
#include <string.h>
/* 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). */
};
static int
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)
goto emsgsize;
ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
if (section != ns_s_qd) {
if (ptr + NS_INT32SZ > eom)
goto emsgsize;
ptr += NS_INT32SZ/*TTL*/;
if (ptr + NS_INT16SZ > eom)
goto emsgsize;
NS_GET16(rdlength, ptr);
ptr += rdlength/*RData*/;
}
}
if (ptr > eom)
goto emsgsize;
return (ptr - optr);
emsgsize:
errno = EMSGSIZE;
return (-1);
}
int
ns_initparse(const u_char *msg, int msglen, ns_msg *handle) {
const u_char *eom = msg + msglen;
int i;
memset(handle, 0x5e, sizeof *handle);
handle->_msg = msg;
handle->_eom = eom;
if (msg + NS_INT16SZ > eom)
goto emsgsize;
NS_GET16(handle->_id, msg);
if (msg + NS_INT16SZ > eom)
goto emsgsize;
NS_GET16(handle->_flags, msg);
for (i = 0; i < ns_s_max; i++) {
if (msg + NS_INT16SZ > eom)
goto 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 = skiprr(msg, eom, (ns_sect)i,
handle->_counts[i]);
if (b < 0)
return (-1);
handle->_sections[i] = msg;
msg += b;
}
if (msg != eom)
goto emsgsize;
handle->_sect = ns_s_max;
handle->_rrnum = -1;
handle->_ptr = NULL;
return (0);
emsgsize:
errno = EMSGSIZE;
return (-1);
}
int
ns_parserr(ns_msg *handle, ns_sect section, int rrnum, ns_rr *rr) {
int b;
/* Make section right. */
if (section < 0 || section >= ns_s_max)
goto enodev;
if ((int)section != (int)handle->_sect) {
handle->_sect = section;
handle->_rrnum = 0;
handle->_ptr = handle->_sections[(int)section];
}
/* Make rrnum right. */
if (rrnum == -1)
rrnum = handle->_rrnum;
if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
goto enodev;
if (rrnum < handle->_rrnum) {
handle->_rrnum = 0;
handle->_ptr = handle->_sections[(int)section];
}
b = skiprr(handle->_msg, handle->_eom, section,
rrnum - handle->_rrnum);
if (b < 0)
return (-1);
handle->_ptr += b;
handle->_rrnum = rrnum;
/* Do the parse. */
b = dn_expand(handle->_msg, handle->_eom,
handle->_ptr, rr->name, NS_MAXDNAME);
if (b < 0)
return (-1);
handle->_ptr += b;
if (handle->_ptr + NS_INT16SZ > handle->_eom)
goto emsgsize;
NS_GET16(rr->type, handle->_ptr);
if (handle->_ptr + NS_INT16SZ > handle->_eom)
goto emsgsize;
NS_GET16(rr->rr_class, handle->_ptr);
if (section == ns_s_qd) {
rr->ttl = 0;
rr->rdlength = 0;
rr->rdata = NULL;
} else {
if (handle->_ptr + NS_INT32SZ > handle->_eom)
goto emsgsize;
NS_GET32(rr->ttl, handle->_ptr);
if (handle->_ptr + NS_INT16SZ > handle->_eom)
goto emsgsize;
NS_GET16(rr->rdlength, handle->_ptr);
if (handle->_ptr + rr->rdlength > handle->_eom)
goto emsgsize;
rr->rdata = handle->_ptr;
handle->_ptr += rr->rdlength;
}
handle->_rrnum++;
/* All done. */
return (0);
enodev:
errno = ENODEV;
return (-1);
emsgsize:
errno = EMSGSIZE;
return (-1);
}
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