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356 lines
7.4 KiB
C
356 lines
7.4 KiB
C
/*
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* Copyright (c) 1996,1999 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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/*
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* Modified by Hotbird64 for use with vlmcs.
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*/
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#ifndef CONFIG
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#define CONFIG "config.h"
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#endif // CONFIG
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#include CONFIG
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#ifdef DNS_PARSER_INTERNAL
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#ifndef NO_DNS
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#include <sys/types.h>
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#include <errno.h>
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#include <string.h>
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#include <ctype.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <limits.h>
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#include "types.h"
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#include "ns_name.h"
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#ifdef SPRINTF_CHAR
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# define SPRINTF(x) strlen(sprintf/**/x)
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#else
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# define SPRINTF(x) ((size_t)sprintf x)
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#endif
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#define NS_TYPE_ELT 0x40 /* EDNS0 extended label type */
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#define DNS_LABELTYPE_BITSTRING 0x41
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#define NS_MAXCDNAME 255
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#define NS_CMPRSFLGS 0xc0
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/* Data. */
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static char digits[] = "0123456789";
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/* Forward. */
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static int special_vlmcsd(int);
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static int printable_vlmcsd(int);
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static int labellen_vlmcsd(const uint8_t *);
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static int decode_bitstring_vlmcsd(const char **, char *, const char *);
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/*
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* ns_name_ntop(src, dst, dstsiz)
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* Convert an encoded domain name to printable ascii as per RFC1035.
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* return:
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* Number of bytes written to buffer, or -1 (with errno set)
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* notes:
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* The root is returned as "."
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* All other domains are returned in non absolute form
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*/
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static int
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ns_name_ntop_vlmcsd(const uint8_t *src, char *dst, size_t dstsiz)
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{
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const uint8_t *cp;
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char *dn, *eom;
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uint8_t c;
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uint32_t n;
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int l;
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cp = src;
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dn = dst;
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eom = dst + dstsiz;
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while ((n = *cp++) != 0) {
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if ((n & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
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/* Some kind of compression pointer. */
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errno = EMSGSIZE;
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return (-1);
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}
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if (dn != dst) {
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if (dn >= eom) {
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errno = EMSGSIZE;
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return (-1);
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}
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*dn++ = '.';
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}
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if ((l = labellen_vlmcsd(cp - 1)) < 0) {
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errno = EMSGSIZE; /* XXX */
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return(-1);
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}
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if (dn + l >= eom) {
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errno = EMSGSIZE;
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return (-1);
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}
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if ((n & NS_CMPRSFLGS) == NS_TYPE_ELT) {
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int m;
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if (n != DNS_LABELTYPE_BITSTRING) {
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/* XXX: labellen should reject this case */
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errno = EINVAL;
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return(-1);
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}
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if ((m = decode_bitstring_vlmcsd((const char **)&cp, dn, eom)) < 0)
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{
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errno = EMSGSIZE;
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return(-1);
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}
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dn += m;
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continue;
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}
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for ((void)NULL; l > 0; l--) {
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c = *cp++;
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if (special_vlmcsd(c)) {
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if (dn + 1 >= eom) {
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errno = EMSGSIZE;
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return (-1);
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}
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*dn++ = '\\';
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*dn++ = (char)c;
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} else if (!printable_vlmcsd(c)) {
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if (dn + 3 >= eom) {
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errno = EMSGSIZE;
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return (-1);
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}
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*dn++ = '\\';
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*dn++ = digits[c / 100];
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*dn++ = digits[(c % 100) / 10];
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*dn++ = digits[c % 10];
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} else {
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if (dn >= eom) {
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errno = EMSGSIZE;
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return (-1);
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}
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*dn++ = (char)c;
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}
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}
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}
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if (dn == dst) {
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if (dn >= eom) {
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errno = EMSGSIZE;
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return (-1);
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}
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*dn++ = '.';
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}
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if (dn >= eom) {
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errno = EMSGSIZE;
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return (-1);
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}
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*dn++ = '\0';
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return (dn - dst);
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}
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static int
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ns_name_unpack_vlmcsd(const uint8_t *msg, const uint8_t *eom, const uint8_t *src,
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uint8_t *dst, size_t dstsiz)
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{
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const uint8_t *srcp, *dstlim;
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uint8_t *dstp;
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int n, len, checked, l;
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len = -1;
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checked = 0;
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dstp = dst;
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srcp = src;
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dstlim = dst + dstsiz;
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if (srcp < msg || srcp >= eom) {
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errno = EMSGSIZE;
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return (-1);
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}
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/* Fetch next label in domain name. */
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while ((n = *srcp++) != 0) {
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/* Check for indirection. */
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switch (n & NS_CMPRSFLGS) {
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case 0:
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case NS_TYPE_ELT:
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/* Limit checks. */
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if ((l = labellen_vlmcsd(srcp - 1)) < 0) {
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errno = EMSGSIZE;
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return(-1);
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}
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if (dstp + l + 1 >= dstlim || srcp + l >= eom) {
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errno = EMSGSIZE;
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return (-1);
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}
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checked += l + 1;
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*dstp++ = n;
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memcpy(dstp, srcp, l);
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dstp += l;
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srcp += l;
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break;
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case NS_CMPRSFLGS:
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if (srcp >= eom) {
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errno = EMSGSIZE;
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return (-1);
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}
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if (len < 0)
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len = srcp - src + 1;
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srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff));
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if (srcp < msg || srcp >= eom) { /* Out of range. */
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errno = EMSGSIZE;
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return (-1);
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}
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checked += 2;
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/*
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* Check for loops in the compressed name;
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* if we've looked at the whole message,
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* there must be a loop.
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*/
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if (checked >= eom - msg) {
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errno = EMSGSIZE;
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return (-1);
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}
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break;
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default:
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errno = EMSGSIZE;
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return (-1); /* flag error */
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}
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}
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*dstp = '\0';
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if (len < 0)
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len = srcp - src;
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return (len);
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}
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/*
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* ns_name_uncompress_vlmcsd(msg, eom, src, dst, dstsiz)
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* Expand compressed domain name to presentation format.
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* return:
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* Number of bytes read out of `src', or -1 (with errno set).
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* note:
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* Root domain returns as "." not "".
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*/
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int
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ns_name_uncompress_vlmcsd(const uint8_t *msg, const uint8_t *eom, const uint8_t *src,
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char *dst, size_t dstsiz)
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{
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uint8_t tmp[NS_MAXCDNAME];
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int n;
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if ((n = ns_name_unpack_vlmcsd(msg, eom, src, tmp, sizeof tmp)) == -1)
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return (-1);
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if (ns_name_ntop_vlmcsd(tmp, dst, dstsiz) == -1)
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return (-1);
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return (n);
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}
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/*
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* special(ch)
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* Thinking in noninternationalized USASCII (per the DNS spec),
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* is this characted special ("in need of quoting") ?
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* return:
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* boolean.
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*/
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static int
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special_vlmcsd(int ch) {
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switch (ch) {
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case 0x22: /* '"' */
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case 0x2E: /* '.' */
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case 0x3B: /* ';' */
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case 0x5C: /* '\\' */
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case 0x28: /* '(' */
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case 0x29: /* ')' */
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/* Special modifiers in zone files. */
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case 0x40: /* '@' */
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case 0x24: /* '$' */
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return (1);
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default:
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return (0);
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}
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}
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/*
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* printable(ch)
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* Thinking in noninternationalized USASCII (per the DNS spec),
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* is this character visible and not a space when printed ?
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* return:
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* boolean.
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*/
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static int
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printable_vlmcsd(int ch) {
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return (ch > 0x20 && ch < 0x7f);
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}
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static int
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decode_bitstring_vlmcsd(const char **cpp, char *dn, const char *eom)
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{
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const char *cp = *cpp;
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char *beg = dn, tc;
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int b, blen, plen;
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if ((blen = (*cp & 0xff)) == 0)
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blen = 256;
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plen = (blen + 3) / 4;
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plen += sizeof("\\[x/]") + (blen > 99 ? 3 : (blen > 9) ? 2 : 1);
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if (dn + plen >= eom)
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return(-1);
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cp++;
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dn += SPRINTF((dn, "\\[x"));
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for (b = blen; b > 7; b -= 8, cp++)
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dn += SPRINTF((dn, "%02x", *cp & 0xff));
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if (b > 4) {
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tc = *cp++;
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dn += SPRINTF((dn, "%02x", tc & (0xff << (8 - b))));
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} else if (b > 0) {
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tc = *cp++;
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dn += SPRINTF((dn, "%1x",
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((tc >> 4) & 0x0f) & (0x0f << (4 - b))));
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}
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dn += SPRINTF((dn, "/%d]", blen));
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*cpp = cp;
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return(dn - beg);
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}
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static int
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labellen_vlmcsd(const uint8_t *lp)
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{
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int bitlen;
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uint8_t l = *lp;
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if ((l & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
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/* should be avoided by the caller */
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return(-1);
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}
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if ((l & NS_CMPRSFLGS) == NS_TYPE_ELT) {
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if (l == DNS_LABELTYPE_BITSTRING) {
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if ((bitlen = *(lp + 1)) == 0)
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bitlen = 256;
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return((bitlen + 7 ) / 8 + 1);
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}
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return(-1); /* unknwon ELT */
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}
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return(l);
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}
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#endif // !NO_DNS
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#endif // DNS_PARSER_INTERNAL
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