StdLib/BsdSocketLib/ns_parse.c

/*
 * 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.
 */

/*
 * Portions copyright (c) 1999, 2000
 * Intel Corporation.
 * 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 Intel Corporation and
 *    its contributors.
 *
 * 4. Neither the name of Intel Corporation or its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY INTEL CORPORATION 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 INTEL CORPORATION 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.
 *
 */

#ifndef lint
static char rcsid[] = "$Id: ns_parse.c,v 1.1.1.1 2003/11/19 01:51:33 kyu3 Exp $";
#endif

#include <sys/types.h>

#include <netinet/in.h>
#include <arpa/nameser.h>

#include <errno.h>
#include <resolv.h>
#include <string.h>

/* 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). */
};

static int
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)
            goto emsgsize;
        ptr += b/*Name*/ + NS_INT16SZ/*Type*/ + NS_INT16SZ/*Class*/;
        if (section != ns_s_qd) {
            if (ptr + NS_INT32SZ > eom)
                goto emsgsize;
            ptr += NS_INT32SZ/*TTL*/;
            if (ptr + NS_INT16SZ > eom)
                goto emsgsize;
            NS_GET16(rdlength, ptr);
            ptr += rdlength/*RData*/;
        }
    }
    if (ptr > eom)
        goto emsgsize;
    return ((int)(ptr - optr));
 emsgsize:
    errno = EMSGSIZE;
    return (-1);
}

int
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)
        goto emsgsize;
    NS_GET16(handle->_id, msg);
    if (msg + NS_INT16SZ > eom)
        goto emsgsize;
    NS_GET16(handle->_flags, msg);
    for (i = 0; i < ns_s_max; i++) {
        if (msg + NS_INT16SZ > eom)
            goto 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 = skiprr(msg, eom, (ns_sect)i,
                       handle->_counts[i]);

            if (b < 0)
                return (-1);
            handle->_sections[i] = msg;
            msg += b;
        }
    if (msg != eom)
        goto emsgsize;
    handle->_sect = ns_s_max;
    handle->_rrnum = -1;
    handle->_msg_ptr = NULL;
    return (0);
 emsgsize:
    errno = EMSGSIZE;
    return (-1);
}

int
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)
        goto enodev;
    if ((int)section != (int)handle->_sect) {
        handle->_sect = section;
        handle->_rrnum = 0;
        handle->_msg_ptr = handle->_sections[(int)section];
    }

    /* Make rrnum right. */
    if (rrnum == -1)
        rrnum = handle->_rrnum;
    if (rrnum < 0 || rrnum >= handle->_counts[(int)section])
        goto enodev;
    if (rrnum < handle->_rrnum) {
        handle->_rrnum = 0;
        handle->_msg_ptr = handle->_sections[(int)section];
    }

    b = skiprr(handle->_msg, handle->_eom, section,
           rrnum - handle->_rrnum);
    if (b < 0)
        return (-1);
    handle->_msg_ptr += b;
    handle->_rrnum = rrnum;

    /* Do the parse. */
    b = dn_expand(handle->_msg, handle->_eom,
              handle->_msg_ptr, rr->name, NS_MAXDNAME);
    if (b < 0)
        return (-1);
    handle->_msg_ptr += b;
    if (handle->_msg_ptr + NS_INT16SZ > handle->_eom)
        goto emsgsize;
    NS_GET16(rr->type, handle->_msg_ptr);
    if (handle->_msg_ptr + NS_INT16SZ > handle->_eom)
        goto emsgsize;
    NS_GET16(rr->rr_class, handle->_msg_ptr);
    if (section == ns_s_qd) {
        rr->ttl = 0;
        rr->rdlength = 0;
        rr->rdata = NULL;
    } else {
        if (handle->_msg_ptr + NS_INT32SZ > handle->_eom)
            goto emsgsize;
        NS_GET32(rr->ttl, handle->_msg_ptr);
        if (handle->_msg_ptr + NS_INT16SZ > handle->_eom)
            goto emsgsize;
        NS_GET16(rr->rdlength, handle->_msg_ptr);
        if (handle->_msg_ptr + rr->rdlength > handle->_eom)
            goto emsgsize;
        rr->rdata = handle->_msg_ptr;
        handle->_msg_ptr += rr->rdlength;
    }
    handle->_rrnum++;

    /* All done. */
    return (0);
 enodev:
    errno = ENODEV;
    return (-1);
 emsgsize:
    errno = EMSGSIZE;
    return (-1);
}