source: rtems/cpukit/libnetworking/libc/ns_parse.c @ 0e16fa45

#include <machine/rtems-bsd-user-space.h>

/*
 * 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.
 */

#if HAVE_CONFIG_H
#include "config.h"
#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 (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->_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->_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->_ptr = handle->_sections[(int)section];
        }
        
        b = skiprr(handle->_msg, 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 > handle->_eom)
                goto emsgsize;
        NS_GET16(rr->type, handle->_ptr);
        if (handle->_ptr + NS_INT16SZ > handle->_eom)
                goto emsgsize;
        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 > handle->_eom)
                        goto emsgsize;
                NS_GET32(rr->ttl, handle->_ptr);
                if (handle->_ptr + NS_INT16SZ > handle->_eom)
                        goto emsgsize;
                NS_GET16(rr->rdlength, handle->_ptr);
                if (handle->_ptr + rr->rdlength > handle->_eom)
                        goto emsgsize;
                rr->rdata = handle->_ptr;
                handle->_ptr += rr->rdlength;
        }
        handle->_rrnum++;

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