190 lines
4.7 KiB
C
190 lines
4.7 KiB
C
/*
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* Copyright (c) 1996 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
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* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
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* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
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* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
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* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
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* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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* SOFTWARE.
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*/
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#include <sys/cdefs.h>
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#include <sys/types.h>
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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 <errno.h>
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#include <resolv.h>
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#include <string.h>
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/* These need to be in the same order as the nres.h:ns_flag enum. */
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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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static int
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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 ((void)NULL; 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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goto 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 > eom)
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goto emsgsize;
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ptr += NS_INT32SZ/*TTL*/;
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if (ptr + NS_INT16SZ > eom)
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goto emsgsize;
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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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goto emsgsize;
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return (ptr - optr);
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emsgsize:
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errno = EMSGSIZE;
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return (-1);
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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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memset(handle, 0x5e, sizeof *handle);
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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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goto emsgsize;
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NS_GET16(handle->_id, msg);
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if (msg + NS_INT16SZ > eom)
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goto 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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goto 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 = 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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goto emsgsize;
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handle->_sect = ns_s_max;
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handle->_rrnum = -1;
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handle->_ptr = NULL;
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return (0);
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emsgsize:
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errno = EMSGSIZE;
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return (-1);
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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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/* Make section right. */
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if (section < 0 || section >= ns_s_max)
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goto enodev;
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if ((int)section != (int)handle->_sect) {
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handle->_sect = section;
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handle->_rrnum = 0;
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handle->_ptr = handle->_sections[(int)section];
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}
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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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goto enodev;
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if (rrnum < handle->_rrnum) {
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handle->_rrnum = 0;
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handle->_ptr = handle->_sections[(int)section];
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}
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b = skiprr(handle->_msg, 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->_ptr += b;
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handle->_rrnum = rrnum;
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/* Do the parse. */
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b = dn_expand(handle->_msg, handle->_eom,
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handle->_ptr, rr->name, NS_MAXDNAME);
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if (b < 0)
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return (-1);
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handle->_ptr += b;
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if (handle->_ptr + NS_INT16SZ > handle->_eom)
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goto emsgsize;
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NS_GET16(rr->type, handle->_ptr);
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if (handle->_ptr + NS_INT16SZ > handle->_eom)
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goto emsgsize;
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NS_GET16(rr->rr_class, handle->_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->_ptr + NS_INT32SZ > handle->_eom)
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goto emsgsize;
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NS_GET32(rr->ttl, handle->_ptr);
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if (handle->_ptr + NS_INT16SZ > handle->_eom)
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goto emsgsize;
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NS_GET16(rr->rdlength, handle->_ptr);
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if (handle->_ptr + rr->rdlength > handle->_eom)
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goto emsgsize;
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rr->rdata = handle->_ptr;
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handle->_ptr += rr->rdlength;
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}
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handle->_rrnum++;
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/* All done. */
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return (0);
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enodev:
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errno = ENODEV;
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return (-1);
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emsgsize:
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errno = EMSGSIZE;
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return (-1);
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}
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