dnsapi: Add DNS message parsing routines from BIND.
This commit is contained in:
Hans Leidekker
Alexandre Julliard
parent
414128eb94
commit
4cbbce8ea6
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@ -10,6 +10,8 @@ EXTRALIBS = $(LIBUNICODE) @RESOLVLIBS@
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C_SRCS = \
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main.c \
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name.c \
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ns_name.c \
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ns_parse.c \
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query.c \
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record.c
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@ -137,3 +137,8 @@ static inline LPSTR dns_strdup_ua( const char *src )
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}
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return dst;
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}
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int dns_ns_initparse( const u_char *, int, ns_msg * );
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int dns_ns_parserr( ns_msg *, ns_sect, int, ns_rr * );
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int dns_ns_name_skip( const u_char **, const u_char * );
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int dns_ns_name_uncompress( const u_char *, const u_char *, const u_char *, char *, size_t );
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@ -0,0 +1,708 @@
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/*
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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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#include "config.h"
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#include <sys/types.h>
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#ifdef HAVE_NETINET_IN_H
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# include <netinet/in.h>
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#endif
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#ifdef HAVE_ARPA_NAMESER_H
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# include <arpa/nameser.h>
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#endif
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#include <ctype.h>
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#include <errno.h>
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#ifdef HAVE_RESOLV_H
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# include <resolv.h>
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#endif
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#include <string.h>
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#include <ctype.h>
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/* Data. */
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static const char digits[] = "0123456789";
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/* Forward. */
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static int special(int);
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static int printable(int);
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static int dn_find(const u_char *, const u_char *,
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const u_char * const *,
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const u_char * const *);
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/* Public. */
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/*
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* dns_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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int
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dns_ns_name_ntop(const u_char *src, char *dst, size_t dstsiz) {
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const u_char *cp;
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char *dn, *eom;
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u_char c;
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u_int n;
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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) != 0 && n != 0x41) {
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/* Some kind of compression pointer. */
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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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return (-1);
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}
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*dn++ = '.';
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}
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if (n == 0x41) {
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n = *cp++ / 8;
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if (dn + n * 2 + 4 >= eom) {
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return (-1);
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}
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*dn++ = '\\';
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*dn++ = '[';
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*dn++ = 'x';
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while (n-- > 0) {
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unsigned u;
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c = *cp++;
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u = c >> 4;
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*dn++ = u > 9 ? 'a' + u - 10 : '0' + u;
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u = c & 0xf;
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*dn++ = u > 9 ? 'a' + u - 10 : '0' + u;
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}
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*dn++ = ']';
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continue;
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}
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if (dn + n >= eom) {
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return (-1);
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}
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for ((void)NULL; n > 0; n--) {
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c = *cp++;
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if (special(c)) {
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if (dn + 1 >= eom) {
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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(c)) {
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if (dn + 3 >= eom) {
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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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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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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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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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/*
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* dns_ns_name_pton(src, dst, dstsiz)
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* Convert a ascii string into an encoded domain name as per RFC1035.
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* return:
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* -1 if it fails
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* 1 if string was fully qualified
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* 0 is string was not fully qualified
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* notes:
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* Enforces label and domain length limits.
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*/
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int
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dns_ns_name_pton(const char *src, u_char *dst, size_t dstsiz) {
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u_char *label, *bp, *eom;
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int c, n, escaped;
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char *cp;
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escaped = 0;
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bp = dst;
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eom = dst + dstsiz;
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label = bp++;
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while ((c = *src++) != 0) {
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if (escaped) {
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if ((cp = strchr(digits, c)) != NULL) {
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n = (cp - digits) * 100;
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if ((c = *src++) == 0 ||
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(cp = strchr(digits, c)) == NULL) {
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return (-1);
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}
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n += (cp - digits) * 10;
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if ((c = *src++) == 0 ||
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(cp = strchr(digits, c)) == NULL) {
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return (-1);
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}
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n += (cp - digits);
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if (n > 255) {
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return (-1);
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}
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c = n;
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} else if (c == '[' && label == bp - 1 && *src == 'x') {
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/* Theoretically we would have to handle \[o
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as well but we do not since we do not need
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it internally. */
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*label = 0x41;
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label = bp++;
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++src;
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while (isxdigit (*src)) {
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n = *src > '9' ? *src - 'a' + 10 : *src - '0';
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++src;
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if (! isxdigit(*src)) {
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return (-1);
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}
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n <<= 4;
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n += *src > '9' ? *src - 'a' + 10 : *src - '0';
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if (bp + 1 >= eom) {
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return (-1);
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}
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*bp++ = n;
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++src;
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}
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*label = (bp - label - 1) * 8;
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if (*src++ != ']' || *src++ != '.') {
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return (-1);
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}
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escaped = 0;
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label = bp++;
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if (bp >= eom) {
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return (-1);
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}
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continue;
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}
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escaped = 0;
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} else if (c == '\\') {
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escaped = 1;
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continue;
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} else if (c == '.') {
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c = (bp - label - 1);
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if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */
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return (-1);
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}
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if (label >= eom) {
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return (-1);
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}
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*label = c;
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/* Fully qualified ? */
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if (*src == '\0') {
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if (c != 0) {
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if (bp >= eom) {
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return (-1);
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}
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*bp++ = '\0';
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}
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if ((bp - dst) > MAXCDNAME) {
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return (-1);
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}
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return (1);
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}
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if (c == 0 || *src == '.') {
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return (-1);
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}
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label = bp++;
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continue;
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}
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if (bp >= eom) {
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return (-1);
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}
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*bp++ = (u_char)c;
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}
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c = (bp - label - 1);
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if ((c & NS_CMPRSFLGS) != 0) { /* Label too big. */
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return (-1);
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}
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if (label >= eom) {
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return (-1);
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}
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*label = c;
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if (c != 0) {
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if (bp >= eom) {
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return (-1);
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}
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*bp++ = 0;
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}
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if ((bp - dst) > MAXCDNAME) { /* src too big */
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return (-1);
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}
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return (0);
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}
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/*
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* ns_name_ntol(src, dst, dstsiz)
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* Convert a network strings labels into all lowercase.
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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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* Enforces label and domain length limits.
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*/
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int
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ns_name_ntol(const u_char *src, u_char *dst, size_t dstsiz) {
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const u_char *cp;
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u_char *dn, *eom;
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u_char c;
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u_int n;
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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) != 0) {
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/* Some kind of compression pointer. */
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return (-1);
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}
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*dn++ = n;
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if (dn + n >= eom) {
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return (-1);
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}
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for ((void)NULL; n > 0; n--) {
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c = *cp++;
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if (isupper(c))
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*dn++ = tolower(c);
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else
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*dn++ = c;
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}
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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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/*
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* dns_ns_name_unpack(msg, eom, src, dst, dstsiz)
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* Unpack a domain name from a message, source may be compressed.
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* return:
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* -1 if it fails, or consumed octets if it succeeds.
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*/
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int
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dns_ns_name_unpack(const u_char *msg, const u_char *eom, const u_char *src,
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u_char *dst, size_t dstsiz)
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{
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const u_char *srcp, *dstlim;
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u_char *dstp;
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int n, len, checked;
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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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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 0x40:
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if (n == 0x41) {
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if (dstp + 1 >= dstlim) {
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return (-1);
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}
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*dstp++ = 0x41;
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n = *srcp++ / 8;
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++checked;
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} else {
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return (-1); /* flag error */
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}
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/* FALLTHROUGH */
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case 0:
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/* Limit checks. */
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if (dstp + n + 1 >= dstlim || srcp + n >= eom) {
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return (-1);
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}
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checked += n + 1;
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dstp = memcpy(dstp, srcp - 1, n + 1);
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dstp += n + 1;
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srcp += n;
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break;
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case NS_CMPRSFLGS:
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if (srcp >= eom) {
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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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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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return (-1);
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}
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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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*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_pack(src, dst, dstsiz, dnptrs, lastdnptr)
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* Pack domain name 'domain' into 'comp_dn'.
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* return:
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* Size of the compressed name, or -1.
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* notes:
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* 'dnptrs' is an array of pointers to previous compressed names.
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* dnptrs[0] is a pointer to the beginning of the message. The array
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* ends with NULL.
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* 'lastdnptr' is a pointer to the end of the array pointed to
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* by 'dnptrs'.
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* Side effects:
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* The list of pointers in dnptrs is updated for labels inserted into
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* the message as we compress the name. If 'dnptr' is NULL, we don't
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* try to compress names. If 'lastdnptr' is NULL, we don't update the
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* list.
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*/
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int
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ns_name_pack(const u_char *src, u_char *dst, int dstsiz,
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const u_char **dnptrs, const u_char **lastdnptr)
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{
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u_char *dstp;
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const u_char **cpp, **lpp, *eob, *msg;
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const u_char *srcp;
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int n, l, first = 1;
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srcp = src;
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dstp = dst;
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eob = dstp + dstsiz;
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lpp = cpp = NULL;
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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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(void)NULL;
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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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/* make sure the domain we are about to add is legal */
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l = 0;
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do {
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n = *srcp;
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if ((n & NS_CMPRSFLGS) != 0 && n != 0x41) {
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return (-1);
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}
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if (n == 0x41)
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n = *++srcp / 8;
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l += n + 1;
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if (l > MAXCDNAME) {
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return (-1);
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}
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srcp += n + 1;
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} while (n != 0);
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/* from here on we need to reset compression pointer array on error */
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srcp = src;
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do {
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/* Look to see if we can use pointers. */
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n = *srcp;
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if (n != 0 && n != 0x41 && msg != NULL) {
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l = dn_find(srcp, msg, (const u_char * const *)dnptrs,
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(const u_char * const *)lpp);
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if (l >= 0) {
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if (dstp + 1 >= eob) {
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goto cleanup;
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}
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*dstp++ = (l >> 8) | NS_CMPRSFLGS;
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*dstp++ = l % 256;
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return (dstp - dst);
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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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(dstp - msg) < 0x4000 && first) {
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*cpp++ = dstp;
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*cpp = NULL;
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first = 0;
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}
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}
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/* copy label to buffer */
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if ((n & NS_CMPRSFLGS) != 0 && n != 0x41) { /* Should not happen. */
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goto cleanup;
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}
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if (n == 0x41) {
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n = *++srcp / 8;
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if (dstp + 1 >= eob)
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goto cleanup;
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*dstp++ = 0x41;
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}
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if (dstp + 1 + n >= eob) {
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goto cleanup;
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}
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memcpy(dstp, srcp, n + 1);
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srcp += n + 1;
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dstp += n + 1;
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} while (n != 0);
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if (dstp > eob) {
|
||||
cleanup:
|
||||
if (msg != NULL)
|
||||
*lpp = NULL;
|
||||
return (-1);
|
||||
}
|
||||
return (dstp - dst);
|
||||
}
|
||||
|
||||
/*
|
||||
* dns_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 "".
|
||||
*/
|
||||
int
|
||||
dns_ns_name_uncompress(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 = dns_ns_name_unpack(msg, eom, src, tmp, sizeof tmp)) == -1)
|
||||
return (-1);
|
||||
if (dns_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.
|
||||
*/
|
||||
int
|
||||
ns_name_compress(const char *src, u_char *dst, size_t dstsiz,
|
||||
const u_char **dnptrs, const u_char **lastdnptr)
|
||||
{
|
||||
u_char tmp[NS_MAXCDNAME];
|
||||
|
||||
if (dns_ns_name_pton(src, tmp, sizeof tmp) == -1)
|
||||
return (-1);
|
||||
return (ns_name_pack(tmp, dst, dstsiz, dnptrs, lastdnptr));
|
||||
}
|
||||
|
||||
/*
|
||||
* Reset dnptrs so that there are no active references to pointers at or
|
||||
* after src.
|
||||
*/
|
||||
void
|
||||
ns_name_rollback(const u_char *src, const u_char **dnptrs,
|
||||
const u_char **lastdnptr)
|
||||
{
|
||||
while (dnptrs < lastdnptr && *dnptrs != NULL) {
|
||||
if (*dnptrs >= src) {
|
||||
*dnptrs = NULL;
|
||||
break;
|
||||
}
|
||||
dnptrs++;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* dns_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.
|
||||
*/
|
||||
int
|
||||
dns_ns_name_skip(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 */
|
||||
return (-1);
|
||||
}
|
||||
break;
|
||||
}
|
||||
if (cp > eom) {
|
||||
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(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(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(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(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++) {
|
||||
sp = *cpp;
|
||||
/*
|
||||
* terminate search on:
|
||||
* root label
|
||||
* compression pointer
|
||||
* unusable offset
|
||||
*/
|
||||
while (*sp != 0 && (*sp & NS_CMPRSFLGS) == 0 &&
|
||||
(sp - msg) < 0x4000) {
|
||||
dn = domain;
|
||||
cp = sp;
|
||||
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 */
|
||||
return (-1);
|
||||
}
|
||||
}
|
||||
next:
|
||||
sp += *sp + 1;
|
||||
}
|
||||
}
|
||||
return (-1);
|
||||
}
|
||||
|
|
@ -0,0 +1,196 @@
|
|||
/*
|
||||
* Copyright (c) 1996,1999 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 "config.h"
|
||||
|
||||
#include <sys/types.h>
|
||||
|
||||
#ifdef HAVE_NETINET_IN_H
|
||||
# include <netinet/in.h>
|
||||
#endif
|
||||
#ifdef HAVE_ARPA_NAMESER_H
|
||||
# include <arpa/nameser.h>
|
||||
#endif
|
||||
|
||||
#include <errno.h>
|
||||
#ifdef HAVE_RESOLV_H
|
||||
# include <resolv.h>
|
||||
#endif
|
||||
#include <string.h>
|
||||
|
||||
/* Forward. */
|
||||
|
||||
static void setsection(ns_msg *msg, ns_sect sect);
|
||||
|
||||
/* Macros. */
|
||||
|
||||
#define RETERR(err) do { return (-1); } while (0)
|
||||
|
||||
/* Public. */
|
||||
|
||||
/* 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). */
|
||||
};
|
||||
|
||||
int
|
||||
ns_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)
|
||||
RETERR(EMSGSIZE);
|
||||
ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
|
||||
if (section != ns_s_qd) {
|
||||
if (ptr + NS_INT32SZ + NS_INT16SZ > eom)
|
||||
RETERR(EMSGSIZE);
|
||||
ptr += NS_INT32SZ/*TTL*/;
|
||||
NS_GET16(rdlength, ptr);
|
||||
ptr += rdlength/*RData*/;
|
||||
}
|
||||
}
|
||||
if (ptr > eom)
|
||||
RETERR(EMSGSIZE);
|
||||
return (ptr - optr);
|
||||
}
|
||||
|
||||
int
|
||||
dns_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)
|
||||
RETERR(EMSGSIZE);
|
||||
NS_GET16(handle->_id, msg);
|
||||
if (msg + NS_INT16SZ > eom)
|
||||
RETERR(EMSGSIZE);
|
||||
NS_GET16(handle->_flags, msg);
|
||||
for (i = 0; i < ns_s_max; i++) {
|
||||
if (msg + NS_INT16SZ > eom)
|
||||
RETERR(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 = ns_skiprr(msg, eom, (ns_sect)i,
|
||||
handle->_counts[i]);
|
||||
|
||||
if (b < 0)
|
||||
return (-1);
|
||||
handle->_sections[i] = msg;
|
||||
msg += b;
|
||||
}
|
||||
if (msg != eom)
|
||||
RETERR(EMSGSIZE);
|
||||
setsection(handle, ns_s_max);
|
||||
return (0);
|
||||
}
|
||||
|
||||
int
|
||||
dns_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)
|
||||
RETERR(ENODEV);
|
||||
if (section != handle->_sect)
|
||||
setsection(handle, section);
|
||||
|
||||
/* Make rrnum right. */
|
||||
if (rrnum == -1)
|
||||
rrnum = handle->_rrnum;
|
||||
if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
|
||||
RETERR(ENODEV);
|
||||
if (rrnum < handle->_rrnum)
|
||||
setsection(handle, section);
|
||||
if (rrnum > handle->_rrnum) {
|
||||
b = ns_skiprr(handle->_ptr, 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 + NS_INT16SZ > handle->_eom)
|
||||
RETERR(EMSGSIZE);
|
||||
NS_GET16(rr->type, handle->_ptr);
|
||||
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 + NS_INT16SZ > handle->_eom)
|
||||
RETERR(EMSGSIZE);
|
||||
NS_GET32(rr->ttl, handle->_ptr);
|
||||
NS_GET16(rr->rdlength, handle->_ptr);
|
||||
if (handle->_ptr + rr->rdlength > handle->_eom)
|
||||
RETERR(EMSGSIZE);
|
||||
rr->rdata = handle->_ptr;
|
||||
handle->_ptr += rr->rdlength;
|
||||
}
|
||||
if (++handle->_rrnum > handle->_counts[(int)section])
|
||||
setsection(handle, (ns_sect)((int)section + 1));
|
||||
|
||||
/* All done. */
|
||||
return (0);
|
||||
}
|
||||
|
||||
/* Private. */
|
||||
|
||||
static void
|
||||
setsection(ns_msg *msg, ns_sect sect) {
|
||||
msg->_sect = sect;
|
||||
if (sect == ns_s_max) {
|
||||
msg->_rrnum = -1;
|
||||
msg->_ptr = NULL;
|
||||
} else {
|
||||
msg->_rrnum = 0;
|
||||
msg->_ptr = msg->_sections[(int)sect];
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue