350 lines
8.1 KiB
C
350 lines
8.1 KiB
C
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/*
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* Copyright (c) 1985 Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)res_comp.c 6.22 (Berkeley) 3/19/91";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/param.h>
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#include <arpa/nameser.h>
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#include <netinet/in.h>
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#include <resolv.h>
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#include <stdio.h>
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static dn_find();
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/*
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* Expand compressed domain name 'comp_dn' to full domain name.
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* 'msg' is a pointer to the begining of the message,
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* 'eomorig' points to the first location after the message,
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* 'exp_dn' is a pointer to a buffer of size 'length' for the result.
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* Return size of compressed name or -1 if there was an error.
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*/
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dn_expand(msg, eomorig, comp_dn, exp_dn, length)
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const u_char *msg, *eomorig, *comp_dn;
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u_char *exp_dn;
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int length;
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{
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register u_char *cp, *dn;
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register int n, c;
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u_char *eom;
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int len = -1, checked = 0;
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dn = exp_dn;
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cp = (u_char *)comp_dn;
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eom = exp_dn + length;
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/*
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* fetch next label in domain name
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*/
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while (n = *cp++) {
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/*
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* Check for indirection
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*/
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switch (n & INDIR_MASK) {
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case 0:
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if (dn != exp_dn) {
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if (dn >= eom)
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return (-1);
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*dn++ = '.';
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}
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if (dn+n >= eom)
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return (-1);
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checked += n + 1;
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while (--n >= 0) {
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if ((c = *cp++) == '.') {
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if (dn + n + 2 >= eom)
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return (-1);
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*dn++ = '\\';
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}
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*dn++ = c;
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if (cp >= eomorig) /* out of range */
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return(-1);
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}
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break;
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case INDIR_MASK:
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if (len < 0)
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len = cp - comp_dn + 1;
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cp = (u_char *)msg + (((n & 0x3f) << 8) | (*cp & 0xff));
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if (cp < msg || cp >= eomorig) /* out of range */
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return(-1);
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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 >= eomorig - msg)
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return (-1);
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break;
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default:
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return (-1); /* flag error */
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}
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}
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*dn = '\0';
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if (len < 0)
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len = cp - comp_dn;
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return (len);
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}
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/*
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* Compress domain name 'exp_dn' into 'comp_dn'.
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* Return the size of the compressed name or -1.
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* 'length' is the size of the array pointed to by 'comp_dn'.
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* 'dnptrs' is a list of pointers to previous compressed names. dnptrs[0]
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* is a pointer to the beginning of the message. The list ends with NULL.
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* 'lastdnptr' is a pointer to the end of the arrary pointed to
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* by 'dnptrs'. Side effect is to update the list of pointers for
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* labels inserted into the message as we compress the name.
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* If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
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* is NULL, we don't update the list.
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*/
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dn_comp(exp_dn, comp_dn, length, dnptrs, lastdnptr)
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const u_char *exp_dn;
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u_char *comp_dn, **dnptrs, **lastdnptr;
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int length;
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{
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register u_char *cp, *dn;
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register int c, l;
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u_char **cpp, **lpp, *sp, *eob;
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u_char *msg;
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dn = (u_char *)exp_dn;
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cp = comp_dn;
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eob = cp + length;
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if (dnptrs != NULL) {
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if ((msg = *dnptrs++) != NULL) {
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for (cpp = dnptrs; *cpp != NULL; cpp++)
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;
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lpp = cpp; /* end of list to search */
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}
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} else
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msg = NULL;
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for (c = *dn++; c != '\0'; ) {
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/* look to see if we can use pointers */
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if (msg != NULL) {
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if ((l = dn_find(dn-1, msg, dnptrs, lpp)) >= 0) {
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if (cp+1 >= eob)
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return (-1);
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*cp++ = (l >> 8) | INDIR_MASK;
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*cp++ = l % 256;
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return (cp - comp_dn);
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}
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/* not found, save it */
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if (lastdnptr != NULL && cpp < lastdnptr-1) {
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*cpp++ = cp;
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*cpp = NULL;
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}
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}
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sp = cp++; /* save ptr to length byte */
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do {
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if (c == '.') {
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c = *dn++;
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break;
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}
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if (c == '\\') {
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if ((c = *dn++) == '\0')
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break;
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}
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if (cp >= eob) {
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if (msg != NULL)
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*lpp = NULL;
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return (-1);
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}
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*cp++ = c;
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} while ((c = *dn++) != '\0');
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/* catch trailing '.'s but not '..' */
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if ((l = cp - sp - 1) == 0 && c == '\0') {
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cp--;
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break;
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}
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if (l <= 0 || l > MAXLABEL) {
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if (msg != NULL)
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*lpp = NULL;
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return (-1);
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}
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*sp = l;
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}
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if (cp >= eob) {
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if (msg != NULL)
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*lpp = NULL;
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return (-1);
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}
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*cp++ = '\0';
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return (cp - comp_dn);
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}
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/*
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* Skip over a compressed domain name. Return the size or -1.
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*/
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__dn_skipname(comp_dn, eom)
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const u_char *comp_dn, *eom;
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{
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register u_char *cp;
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register int n;
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cp = (u_char *)comp_dn;
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while (cp < eom && (n = *cp++)) {
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/*
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* check for indirection
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*/
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switch (n & INDIR_MASK) {
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case 0: /* normal case, n == len */
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cp += n;
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continue;
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default: /* illegal type */
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return (-1);
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case INDIR_MASK: /* indirection */
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cp++;
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}
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break;
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}
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return (cp - comp_dn);
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}
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/*
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* Search for expanded name from a list of previously compressed names.
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* Return the offset from msg if found or -1.
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* dnptrs is the pointer to the first name on the list,
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* not the pointer to the start of the message.
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*/
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static
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dn_find(exp_dn, msg, dnptrs, lastdnptr)
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u_char *exp_dn, *msg;
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u_char **dnptrs, **lastdnptr;
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{
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register u_char *dn, *cp, **cpp;
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register int n;
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u_char *sp;
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for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
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dn = exp_dn;
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sp = cp = *cpp;
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while (n = *cp++) {
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/*
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* check for indirection
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*/
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switch (n & INDIR_MASK) {
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case 0: /* normal case, n == len */
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while (--n >= 0) {
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if (*dn == '.')
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goto next;
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if (*dn == '\\')
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dn++;
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if (*dn++ != *cp++)
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goto next;
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}
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if ((n = *dn++) == '\0' && *cp == '\0')
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return (sp - msg);
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if (n == '.')
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continue;
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goto next;
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default: /* illegal type */
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return (-1);
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case INDIR_MASK: /* indirection */
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cp = msg + (((n & 0x3f) << 8) | *cp);
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}
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}
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if (*dn == '\0')
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return (sp - msg);
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next: ;
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}
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return (-1);
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}
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/*
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* Routines to insert/extract short/long's. Must account for byte
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* order and non-alignment problems. This code at least has the
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* advantage of being portable.
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*
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* used by sendmail.
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*/
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u_short
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_getshort(msgp)
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u_char *msgp;
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{
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register u_char *p = (u_char *) msgp;
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#ifdef vax
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/*
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* vax compiler doesn't put shorts in registers
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*/
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register u_long u;
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#else
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register u_short u;
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#endif
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u = *p++ << 8;
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return ((u_short)(u | *p));
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}
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u_long
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_getlong(msgp)
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u_char *msgp;
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{
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register u_char *p = (u_char *) msgp;
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register u_long u;
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u = *p++; u <<= 8;
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u |= *p++; u <<= 8;
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u |= *p++; u <<= 8;
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return (u | *p);
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}
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void
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#ifdef __STDC__
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__putshort(register u_short s, register u_char *msgp)
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#else
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__putshort(s, msgp)
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register u_short s;
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register u_char *msgp;
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#endif
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{
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msgp[1] = s;
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msgp[0] = s >> 8;
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}
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void
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__putlong(l, msgp)
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register u_long l;
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register u_char *msgp;
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{
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msgp[3] = l;
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msgp[2] = (l >>= 8);
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msgp[1] = (l >>= 8);
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msgp[0] = l >> 8;
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}
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