freebsd-dev/lib/libc/net/res_comp.c
Peter Wemm c8d2fd6da8 Update libc dns code to 4.9.7-T1B level. This involved chopping out large
chunks of res_comp.c and replacing it with chunks of bind-8.1.1's resolver
code.  (There are no interface changes though)
The other parts are better bounds checking related.
1998-05-02 13:11:02 +00:00

923 lines
21 KiB
C

/*
* ++Copyright++ 1985, 1993
* -
* Copyright (c) 1985, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* -
* Portions Copyright (c) 1993 by Digital Equipment Corporation.
*
* 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, and that
* the name of Digital Equipment Corporation not be used in advertising or
* publicity pertaining to distribution of the document or software without
* specific, written prior permission.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
* CORPORATION 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.
* -
* --Copyright--
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)res_comp.c 8.1 (Berkeley) 6/4/93";
static char orig_rcsid[] = "From: Id: res_comp.c,v 8.13 1998/04/07 04:24:06 vixie Exp $";
static char rcsid[] = "$Id: res_comp.c,v 1.12 1997/06/27 08:22:02 peter Exp $";
#endif /* LIBC_SCCS and not lint */
#include <sys/types.h>
#include <sys/param.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <stdio.h>
#include <resolv.h>
#include <ctype.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
static int ns_name_ntop __P((const u_char *, char *, size_t));
static int ns_name_pton __P((const char *, u_char *, size_t));
static int ns_name_unpack __P((const u_char *, const u_char *,
const u_char *, u_char *, size_t));
static int ns_name_pack __P((const u_char *, u_char *, int,
const u_char **, const u_char **));
static int ns_name_uncompress __P((const u_char *, const u_char *,
const u_char *, char *, size_t));
static int ns_name_compress __P((const char *, u_char *, size_t,
const u_char **, const u_char **));
static int ns_name_skip __P((const u_char **, const u_char *));
/*
* Expand compressed domain name 'comp_dn' to full domain name.
* 'msg' is a pointer to the begining of the message,
* 'eomorig' points to the first location after the message,
* 'exp_dn' is a pointer to a buffer of size 'length' for the result.
* Return size of compressed name or -1 if there was an error.
*/
int
dn_expand(const u_char *msg, const u_char *eom, const u_char *src,
char *dst, int dstsiz)
{
int n = ns_name_uncompress(msg, eom, src, dst, (size_t)dstsiz);
if (n > 0 && dst[0] == '.')
dst[0] = '\0';
return (n);
}
/*
* Pack domain name 'exp_dn' in presentation form into 'comp_dn'.
* Return the size of the compressed name or -1.
* 'length' is the size of the array pointed to by 'comp_dn'.
*/
int
dn_comp(const char *src, u_char *dst, int dstsiz,
u_char **dnptrs, u_char **lastdnptr)
{
return (ns_name_compress(src, dst, (size_t)dstsiz,
(const u_char **)dnptrs,
(const u_char **)lastdnptr));
}
/*
* Skip over a compressed domain name. Return the size or -1.
*/
int
__dn_skipname(const u_char *ptr, const u_char *eom) {
const u_char *saveptr = ptr;
if (ns_name_skip(&ptr, eom) == -1)
return (-1);
return (ptr - saveptr);
}
/*
* Verify that a domain name uses an acceptable character set.
*/
/*
* Note the conspicuous absence of ctype macros in these definitions. On
* non-ASCII hosts, we can't depend on string literals or ctype macros to
* tell us anything about network-format data. The rest of the BIND system
* is not careful about this, but for some reason, we're doing it right here.
*/
#define PERIOD 0x2e
#define hyphenchar(c) ((c) == 0x2d)
#define bslashchar(c) ((c) == 0x5c)
#define periodchar(c) ((c) == PERIOD)
#define asterchar(c) ((c) == 0x2a)
#define alphachar(c) (((c) >= 0x41 && (c) <= 0x5a) \
|| ((c) >= 0x61 && (c) <= 0x7a))
#define digitchar(c) ((c) >= 0x30 && (c) <= 0x39)
#define borderchar(c) (alphachar(c) || digitchar(c))
#define middlechar(c) (borderchar(c) || hyphenchar(c))
#define domainchar(c) ((c) > 0x20 && (c) < 0x7f)
int
res_hnok(dn)
const char *dn;
{
int ppch = '\0', pch = PERIOD, ch = *dn++;
while (ch != '\0') {
int nch = *dn++;
if (periodchar(ch)) {
NULL;
} else if (periodchar(pch)) {
if (!borderchar(ch))
return (0);
} else if (periodchar(nch) || nch == '\0') {
if (!borderchar(ch))
return (0);
} else {
if (!middlechar(ch))
return (0);
}
ppch = pch, pch = ch, ch = nch;
}
return (1);
}
/*
* hostname-like (A, MX, WKS) owners can have "*" as their first label
* but must otherwise be as a host name.
*/
int
res_ownok(dn)
const char *dn;
{
if (asterchar(dn[0])) {
if (periodchar(dn[1]))
return (res_hnok(dn+2));
if (dn[1] == '\0')
return (1);
}
return (res_hnok(dn));
}
/*
* SOA RNAMEs and RP RNAMEs can have any printable character in their first
* label, but the rest of the name has to look like a host name.
*/
int
res_mailok(dn)
const char *dn;
{
int ch, escaped = 0;
/* "." is a valid missing representation */
if (*dn == '\0')
return(1);
/* otherwise <label>.<hostname> */
while ((ch = *dn++) != '\0') {
if (!domainchar(ch))
return (0);
if (!escaped && periodchar(ch))
break;
if (escaped)
escaped = 0;
else if (bslashchar(ch))
escaped = 1;
}
if (periodchar(ch))
return (res_hnok(dn));
return(0);
}
/*
* This function is quite liberal, since RFC 1034's character sets are only
* recommendations.
*/
int
res_dnok(dn)
const char *dn;
{
int ch;
while ((ch = *dn++) != '\0')
if (!domainchar(ch))
return (0);
return (1);
}
/*
* Routines to insert/extract short/long's.
*/
u_int16_t
_getshort(msgp)
register const u_char *msgp;
{
register u_int16_t u;
GETSHORT(u, msgp);
return (u);
}
u_int32_t
_getlong(msgp)
register const u_char *msgp;
{
register u_int32_t u;
GETLONG(u, msgp);
return (u);
}
void
#if defined(__STDC__) || defined(__cplusplus)
__putshort(register u_int16_t s, register u_char *msgp) /* must match proto */
#else
__putshort(s, msgp)
register u_int16_t s;
register u_char *msgp;
#endif
{
PUTSHORT(s, msgp);
}
void
__putlong(l, msgp)
register u_int32_t l;
register u_char *msgp;
{
PUTLONG(l, msgp);
}
/* ++ From BIND 8.1.1. ++ */
/*
* 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.
*/
/*"Id: ns_name.c,v 1.1 1997/12/13 02:41:13 vixie Exp vixie"*/
/*#include "port_before.h"*/
/*#include <sys/types.h>*/
/*#include <netinet/in.h>*/
/*#include <arpa/nameser.h>*/
/*#include <errno.h>*/
/*#include <resolv.h>*/
/*#include <string.h>*/
/*#include "port_after.h"*/
#define NS_CMPRSFLGS 0xc0 /* Flag bits indicating name compression. */
#define NS_MAXCDNAME 255 /* maximum compressed domain name */
/* Data. */
static char digits[] = "0123456789";
/* Forward. */
static int special(int);
static int printable(int);
static int dn_find(const u_char *, const u_char *,
const u_char * const *,
const u_char * const *);
/* Public. */
/*
* ns_name_ntop(src, dst, dstsiz)
* Convert an encoded domain name to printable ascii as per RFC1035.
* return:
* Number of bytes written to buffer, or -1 (with errno set)
* notes:
* The root is returned as "."
* All other domains are returned in non absolute form
*/
static int
ns_name_ntop(src, dst, dstsiz)
const u_char *src;
char *dst;
size_t dstsiz;
{
const u_char *cp;
char *dn, *eom;
u_char c;
u_int n;
cp = src;
dn = dst;
eom = dst + dstsiz;
while ((n = *cp++) != 0) {
if ((n & NS_CMPRSFLGS) != 0) {
/* Some kind of compression pointer. */
errno = EMSGSIZE;
return (-1);
}
if (dn != dst) {
if (dn >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '.';
}
if (dn + n >= eom) {
errno = EMSGSIZE;
return (-1);
}
for ((void)NULL; n > 0; n--) {
c = *cp++;
if (special(c)) {
if (dn + 1 >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '\\';
*dn++ = (char)c;
} else if (!printable(c)) {
if (dn + 3 >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '\\';
*dn++ = digits[c / 100];
*dn++ = digits[(c % 100) / 10];
*dn++ = digits[c % 10];
} else {
if (dn >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = (char)c;
}
}
}
if (dn == dst) {
if (dn >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '.';
}
if (dn >= eom) {
errno = EMSGSIZE;
return (-1);
}
*dn++ = '\0';
return (dn - dst);
}
/*
* ns_name_pton(src, dst, dstsiz)
* Convert a ascii string into an encoded domain name as per RFC1035.
* return:
* -1 if it fails
* 1 if string was fully qualified
* 0 is string was not fully qualified
* notes:
* Enforces label and domain length limits.
*/
static int
ns_name_pton(src, dst, dstsiz)
const char *src;
u_char *dst;
size_t dstsiz;
{
u_char *label, *bp, *eom;
int c, n, escaped;
char *cp;
escaped = 0;
bp = dst;
eom = dst + dstsiz;
label = bp++;
while ((c = *src++) != 0) {
if (escaped) {
if ((cp = strchr(digits, c)) != NULL) {
n = (cp - digits) * 100;
if ((c = *src++) == 0 ||
(cp = strchr(digits, c)) == NULL) {
errno = EMSGSIZE;
return (-1);
}
n += (cp - digits) * 10;
if ((c = *src++) == 0 ||
(cp = strchr(digits, c)) == NULL) {
errno = EMSGSIZE;
return (-1);
}
n += (cp - digits);
if (n > 255) {
errno = EMSGSIZE;
return (-1);
}
c = n;
}
escaped = 0;
} else if (c == '\\') {
escaped = 1;
continue;
} else if (c == '.') {
c = (bp - label - 1);
if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */
errno = EMSGSIZE;
return (-1);
}
if (label >= eom) {
errno = EMSGSIZE;
return (-1);
}
*label = c;
/* Fully qualified ? */
if (*src == '\0') {
if (c != 0) {
if (bp >= eom) {
errno = EMSGSIZE;
return (-1);
}
*bp++ = '\0';
}
if ((bp - dst) > MAXCDNAME) {
errno = EMSGSIZE;
return (-1);
}
return (1);
}
if (c == 0) {
errno = EMSGSIZE;
return (-1);
}
label = bp++;
continue;
}
if (bp >= eom) {
errno = EMSGSIZE;
return (-1);
}
*bp++ = (u_char)c;
}
c = (bp - label - 1);
if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */
errno = EMSGSIZE;
return (-1);
}
if (label >= eom) {
errno = EMSGSIZE;
return (-1);
}
*label = c;
if (c != 0) {
if (bp >= eom) {
errno = EMSGSIZE;
return (-1);
}
*bp++ = 0;
}
if ((bp - dst) > MAXCDNAME) { /* src too big */
errno = EMSGSIZE;
return (-1);
}
return (0);
}
/*
* ns_name_unpack(msg, eom, src, dst, dstsiz)
* Unpack a domain name from a message, source may be compressed.
* return:
* -1 if it fails, or consumed octets if it succeeds.
*/
static int
ns_name_unpack(msg, eom, src, dst, dstsiz)
const u_char *msg;
const u_char *eom;
const u_char *src;
u_char *dst;
size_t dstsiz;
{
const u_char *srcp, *dstlim;
u_char *dstp;
int n, c, len, checked;
len = -1;
checked = 0;
dstp = dst;
srcp = src;
dstlim = dst + dstsiz;
if (srcp < msg || srcp >= eom) {
errno = EMSGSIZE;
return (-1);
}
/* Fetch next label in domain name. */
while ((n = *srcp++) != 0) {
/* Check for indirection. */
switch (n & NS_CMPRSFLGS) {
case 0:
/* Limit checks. */
if (dstp + n + 1 >= dstlim || srcp + n >= eom) {
errno = EMSGSIZE;
return (-1);
}
checked += n + 1;
*dstp++ = n;
memcpy(dstp, srcp, n);
dstp += n;
srcp += n;
break;
case NS_CMPRSFLGS:
if (srcp >= eom) {
errno = EMSGSIZE;
return (-1);
}
if (len < 0)
len = srcp - src + 1;
srcp = msg + (((n & 0x3f) << 8) | (*srcp & 0xff));
if (srcp < msg || srcp >= eom) { /* Out of range. */
errno = EMSGSIZE;
return (-1);
}
checked += 2;
/*
* Check for loops in the compressed name;
* if we've looked at the whole message,
* there must be a loop.
*/
if (checked >= eom - msg) {
errno = EMSGSIZE;
return (-1);
}
break;
default:
errno = EMSGSIZE;
return (-1); /* flag error */
}
}
*dstp = '\0';
if (len < 0)
len = srcp - src;
return (len);
}
/*
* ns_name_pack(src, dst, dstsiz, dnptrs, lastdnptr)
* Pack domain name 'domain' into 'comp_dn'.
* return:
* Size of the compressed name, or -1.
* notes:
* 'dnptrs' is an array of pointers to previous compressed names.
* dnptrs[0] is a pointer to the beginning of the message. The array
* ends with NULL.
* 'lastdnptr' is a pointer to the end of the array pointed to
* by 'dnptrs'.
* Side effects:
* The list of pointers in dnptrs is updated for labels inserted into
* the message as we compress the name. If 'dnptr' is NULL, we don't
* try to compress names. If 'lastdnptr' is NULL, we don't update the
* list.
*/
static int
ns_name_pack(src, dst, dstsiz, dnptrs, lastdnptr)
const u_char *src;
u_char *dst;
int dstsiz;
const u_char **dnptrs;
const u_char **lastdnptr;
{
u_char *dstp;
const u_char **cpp, **lpp, *eob, *msg;
const u_char *srcp;
int n, l;
srcp = src;
dstp = dst;
eob = dstp + dstsiz;
lpp = cpp = NULL;
if (dnptrs != NULL) {
if ((msg = *dnptrs++) != NULL) {
for (cpp = dnptrs; *cpp != NULL; cpp++)
(void)NULL;
lpp = cpp; /* end of list to search */
}
} else
msg = NULL;
/* make sure the domain we are about to add is legal */
l = 0;
do {
n = *srcp;
if ((n & NS_CMPRSFLGS) != 0) {
errno = EMSGSIZE;
return (-1);
}
l += n + 1;
if (l > MAXCDNAME) {
errno = EMSGSIZE;
return (-1);
}
srcp += n + 1;
} while (n != 0);
srcp = src;
do {
/* Look to see if we can use pointers. */
n = *srcp;
if (n != 0 && msg != NULL) {
l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
(const u_char * const *)lpp);
if (l >= 0) {
if (dstp + 1 >= eob) {
errno = EMSGSIZE;
return (-1);
}
*dstp++ = (l >> 8) | NS_CMPRSFLGS;
*dstp++ = l % 256;
return (dstp - dst);
}
/* Not found, save it. */
if (lastdnptr != NULL && cpp < lastdnptr - 1 &&
(dstp - msg) < 0x4000) {
*cpp++ = dstp;
*cpp = NULL;
}
}
/* copy label to buffer */
if (n & NS_CMPRSFLGS) { /* Should not happen. */
errno = EMSGSIZE;
return (-1);
}
if (dstp + 1 + n >= eob) {
errno = EMSGSIZE;
return (-1);
}
memcpy(dstp, srcp, n + 1);
srcp += n + 1;
dstp += n + 1;
} while (n != 0);
if (dstp > eob) {
if (msg != NULL)
*lpp = NULL;
errno = EMSGSIZE;
return (-1);
}
return (dstp - dst);
}
/*
* ns_name_uncompress(msg, eom, src, dst, dstsiz)
* Expand compressed domain name to presentation format.
* return:
* Number of bytes read out of `src', or -1 (with errno set).
* note:
* Root domain returns as "." not "".
*/
static int
ns_name_uncompress(msg, eom, src, dst, dstsiz)
const u_char *msg;
const u_char *eom;
const u_char *src;
char *dst;
size_t dstsiz;
{
u_char tmp[NS_MAXCDNAME];
int n;
if ((n = ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
return (-1);
if (ns_name_ntop(tmp, dst, dstsiz) == -1)
return (-1);
return (n);
}
/*
* ns_name_compress(src, dst, dstsiz, dnptrs, lastdnptr)
* Compress a domain name into wire format, using compression pointers.
* return:
* Number of bytes consumed in `dst' or -1 (with errno set).
* notes:
* 'dnptrs' is an array of pointers to previous compressed names.
* dnptrs[0] is a pointer to the beginning of the message.
* The list ends with NULL. 'lastdnptr' is a pointer to the end of the
* array pointed to by 'dnptrs'. Side effect is to update the list of
* pointers for labels inserted into the message as we compress the name.
* If 'dnptr' is NULL, we don't try to compress names. If 'lastdnptr'
* is NULL, we don't update the list.
*/
static int
ns_name_compress(src, dst, dstsiz, dnptrs, lastdnptr)
const char *src;
u_char *dst;
size_t dstsiz;
const u_char **dnptrs;
const u_char **lastdnptr;
{
u_char tmp[NS_MAXCDNAME];
if (ns_name_pton(src, tmp, sizeof tmp) == -1)
return (-1);
return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
}
/*
* ns_name_skip(ptrptr, eom)
* Advance *ptrptr to skip over the compressed name it points at.
* return:
* 0 on success, -1 (with errno set) on failure.
*/
static int
ns_name_skip(ptrptr, eom)
const u_char **ptrptr;
const u_char *eom;
{
const u_char *cp;
u_int n;
cp = *ptrptr;
while (cp < eom && (n = *cp++) != 0) {
/* Check for indirection. */
switch (n & NS_CMPRSFLGS) {
case 0: /* normal case, n == len */
cp += n;
continue;
case NS_CMPRSFLGS: /* indirection */
cp++;
break;
default: /* illegal type */
errno = EMSGSIZE;
return (-1);
}
break;
}
if (cp > eom) {
errno = EMSGSIZE;
return (-1);
}
*ptrptr = cp;
return (0);
}
/* Private. */
/*
* special(ch)
* Thinking in noninternationalized USASCII (per the DNS spec),
* is this characted special ("in need of quoting") ?
* return:
* boolean.
*/
static int
special(ch)
int ch;
{
switch (ch) {
case 0x22: /* '"' */
case 0x2E: /* '.' */
case 0x3B: /* ';' */
case 0x5C: /* '\\' */
/* Special modifiers in zone files. */
case 0x40: /* '@' */
case 0x24: /* '$' */
return (1);
default:
return (0);
}
}
/*
* printable(ch)
* Thinking in noninternationalized USASCII (per the DNS spec),
* is this character visible and not a space when printed ?
* return:
* boolean.
*/
static int
printable(ch)
int ch;
{
return (ch > 0x20 && ch < 0x7f);
}
/*
* Thinking in noninternationalized USASCII (per the DNS spec),
* convert this character to lower case if it's upper case.
*/
static int
mklower(ch)
int ch;
{
if (ch >= 0x41 && ch <= 0x5A)
return (ch + 0x20);
return (ch);
}
/*
* dn_find(domain, msg, dnptrs, lastdnptr)
* Search for the counted-label name in an array of compressed names.
* return:
* offset from msg if found, or -1.
* notes:
* dnptrs is the pointer to the first name on the list,
* not the pointer to the start of the message.
*/
static int
dn_find(domain, msg, dnptrs, lastdnptr)
const u_char *domain;
const u_char *msg;
const u_char * const *dnptrs;
const u_char * const *lastdnptr;
{
const u_char *dn, *cp, *sp;
const u_char * const *cpp;
u_int n;
for (cpp = dnptrs; cpp < lastdnptr; cpp++) {
dn = domain;
sp = cp = *cpp;
while ((n = *cp++) != 0) {
/*
* check for indirection
*/
switch (n & NS_CMPRSFLGS) {
case 0: /* normal case, n == len */
if (n != *dn++)
goto next;
for ((void)NULL; n > 0; n--)
if (mklower(*dn++) != mklower(*cp++))
goto next;
/* Is next root for both ? */
if (*dn == '\0' && *cp == '\0')
return (sp - msg);
if (*dn)
continue;
goto next;
case NS_CMPRSFLGS: /* indirection */
cp = msg + (((n & 0x3f) << 8) | *cp);
break;
default: /* illegal type */
errno = EMSGSIZE;
return (-1);
}
}
next: ;
}
errno = ENOENT;
return (-1);
}
/* -- From BIND 8.1.1. -- */