/** @file
  Copyright (c) 1999 - 2014, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials are licensed and made available
  under the terms and conditions of the BSD License which accompanies this
  distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php.

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
/*
 * 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.
 *
 */

/*
 * Based on the Dynamic DNS reference implementation by Viraj Bais
 * <viraj_bais@ccm.fm.intel.com>
 */

#include <sys/types.h>
#include <sys/param.h>

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

#include <errno.h>
#include <limits.h>
#include <netdb.h>
#include <resolv.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>

#include "res_config.h"

static int getnum_str(u_char **, u_char *);
static int getword_str(char *, int, u_char **, u_char *);

#define ShrinkBuffer(x)  if ((buflen -= x) < 0) return (-2);

/*
 * Form update packets.
 * Returns the size of the resulting packet if no error
 * On error,
 *  returns -1 if error in reading a word/number in rdata
 *         portion for update packets
 *      -2 if length of buffer passed is insufficient
 *      -3 if zone section is not the first section in
 *         the linked list, or section order has a problem
 *      -4 on a number overflow
 *      -5 unknown operation or no records
 */
int
res_mkupdate(ns_updrec *rrecp_in, u_char *buf, int buflen) {
    ns_updrec *rrecp_start = rrecp_in;
    HEADER *hp;
    u_char *cp, *sp2, *startp, *endp;
    int n, i, soanum, multiline;
    ns_updrec *rrecp;
    struct in_addr ina;
        char buf2[MAXDNAME];
    int section, numrrs = 0, counts[ns_s_max];
    u_int16_t rtype, rclass;
    u_int32_t n1, rttl;
    u_char *dnptrs[20], **dpp, **lastdnptr;

    if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
        h_errno = NETDB_INTERNAL;
        return (-1);
    }

    /*
     * Initialize header fields.
     */
    if ((buf == NULL) || (buflen < HFIXEDSZ))
        return (-1);
    memset(buf, 0, HFIXEDSZ);
    hp = (HEADER *) buf;
    hp->id = htons(++_res.id);
    hp->opcode = ns_o_update;
    hp->rcode = NOERROR;
    cp = buf + HFIXEDSZ;
    buflen -= HFIXEDSZ;
    dpp = dnptrs;
    *dpp++ = buf;
    *dpp++ = NULL;
    lastdnptr = dnptrs + sizeof dnptrs / sizeof dnptrs[0];

    if (rrecp_start == NULL)
        return (-5);
    else if (rrecp_start->r_section != S_ZONE)
        return (-3);

    memset(counts, 0, sizeof counts);
    for (rrecp = rrecp_start; rrecp; rrecp = rrecp->r_grpnext) {
        numrrs++;
                section = rrecp->r_section;
        if (section < 0 || section >= ns_s_max)
            return (-1);
        counts[section]++;
        for (i = section + 1; i < ns_s_max; i++)
            if (counts[i])
                return (-3);
        rtype = rrecp->r_type;
        rclass = rrecp->r_class;
        rttl = rrecp->r_ttl;
        /* overload class and type */
        if (section == S_PREREQ) {
            rttl = 0;
            switch (rrecp->r_opcode) {
            case YXDOMAIN:
                rclass = C_ANY;
                rtype = T_ANY;
                rrecp->r_size = 0;
                break;
            case NXDOMAIN:
                rclass = C_NONE;
                rtype = T_ANY;
                rrecp->r_size = 0;
                break;
            case NXRRSET:
                rclass = C_NONE;
                rrecp->r_size = 0;
                break;
            case YXRRSET:
                if (rrecp->r_size == 0)
                    rclass = C_ANY;
                break;
            default:
                fprintf(stderr,
                    "res_mkupdate: incorrect opcode: %d\n",
                    rrecp->r_opcode);
                fflush(stderr);
                return (-1);
            }
        } else if (section == S_UPDATE) {
            switch (rrecp->r_opcode) {
            case DELETE:
                rclass = rrecp->r_size == 0 ? C_ANY : C_NONE;
                break;
            case ADD:
                break;
            default:
                fprintf(stderr,
                    "res_mkupdate: incorrect opcode: %d\n",
                    rrecp->r_opcode);
                fflush(stderr);
                return (-1);
            }
        }

        /*
         * XXX  appending default domain to owner name is omitted,
         *  fqdn must be provided
         */
        if ((n = dn_comp(rrecp->r_dname, cp, buflen, dnptrs,
                 lastdnptr)) < 0)
            return (-1);
        cp += n;
        ShrinkBuffer(n + 2*INT16SZ);
        PUTSHORT(rtype, cp);
        PUTSHORT(rclass, cp);
        if (section == S_ZONE) {
            if (numrrs != 1 || rrecp->r_type != T_SOA)
                return (-3);
            continue;
        }
        ShrinkBuffer(INT32SZ + INT16SZ);
        PUTLONG(rttl, cp);
        sp2 = cp;  /* save pointer to length byte */
        cp += INT16SZ;
        if (rrecp->r_size == 0) {
            if (section == S_UPDATE && rclass != C_ANY)
                return (-1);
            else {
                PUTSHORT(0, sp2);
                continue;
            }
        }
        startp = rrecp->r_data;
        endp = startp + rrecp->r_size - 1;
        /* XXX this should be done centrally. */
        switch (rrecp->r_type) {
        case T_A:
            if (!getword_str(buf2, sizeof buf2, &startp, endp))
                return (-1);
            if (!inet_aton(buf2, &ina))
                return (-1);
            n1 = ntohl(ina.s_addr);
            ShrinkBuffer(INT32SZ);
            PUTLONG(n1, cp);
            break;
        case T_CNAME:
        case T_MB:
        case T_MG:
        case T_MR:
        case T_NS:
        case T_PTR:
            if (!getword_str(buf2, sizeof buf2, &startp, endp))
                return (-1);
            n = dn_comp(buf2, cp, buflen, dnptrs, lastdnptr);
            if (n < 0)
                return (-1);
            cp += n;
            ShrinkBuffer(n);
            break;
        case T_MINFO:
        case T_SOA:
        case T_RP:
            for (i = 0; i < 2; i++) {
                if (!getword_str(buf2, sizeof buf2, &startp,
                         endp))
                return (-1);
                n = dn_comp(buf2, cp, buflen,
                        dnptrs, lastdnptr);
                if (n < 0)
                    return (-1);
                cp += n;
                ShrinkBuffer(n);
            }
            if (rrecp->r_type == T_SOA) {
                ShrinkBuffer(5 * INT32SZ);
                while (isspace(*startp) || !*startp)
                    startp++;
                if (*startp == '(') {
                    multiline = 1;
                    startp++;
                } else
                    multiline = 0;
                /* serial, refresh, retry, expire, minimum */
                for (i = 0; i < 5; i++) {
                    soanum = getnum_str(&startp, endp);
                    if (soanum < 0)
                        return (-1);
                    PUTLONG(soanum, cp);
                }
                if (multiline) {
                    while (isspace(*startp) || !*startp)
                        startp++;
                    if (*startp != ')')
                        return (-1);
                }
            }
            break;
        case T_MX:
        case T_AFSDB:
        case T_RT:
            n = getnum_str(&startp, endp);
            if (n < 0)
                return (-1);
            PUTSHORT(n, cp);
            ShrinkBuffer(INT16SZ);
            if (!getword_str(buf2, sizeof buf2, &startp, endp))
                return (-1);
            n = dn_comp(buf2, cp, buflen, dnptrs, lastdnptr);
            if (n < 0)
                return (-1);
            cp += n;
            ShrinkBuffer(n);
            break;
        case T_PX:
            n = getnum_str(&startp, endp);
            if (n < 0)
                return (-1);
            PUTSHORT(n, cp);
            ShrinkBuffer(INT16SZ);
            for (i = 0; i < 2; i++) {
                if (!getword_str(buf2, sizeof buf2, &startp,
                         endp))
                    return (-1);
                n = dn_comp(buf2, cp, buflen, dnptrs,
                        lastdnptr);
                if (n < 0)
                    return (-1);
                cp += n;
                ShrinkBuffer(n);
            }
            break;
        case T_WKS:
        case T_HINFO:
        case T_TXT:
        case T_X25:
        case T_ISDN:
        case T_NSAP:
        case T_LOC:
            /* XXX - more fine tuning needed here */
            ShrinkBuffer(rrecp->r_size);
            memcpy(cp, rrecp->r_data, rrecp->r_size);
            cp += rrecp->r_size;
            break;
        default:
            return (-1);
        } /*switch*/
        n = (u_int16_t)((cp - sp2) - INT16SZ);
        PUTSHORT(n, sp2);
    } /*for*/

    hp->qdcount = htons(counts[0]);
    hp->ancount = htons(counts[1]);
    hp->nscount = htons(counts[2]);
    hp->arcount = htons(counts[3]);
    return ((int)(cp - buf));
}

/*
 * Get a whitespace delimited word from a string (not file)
 * into buf. modify the start pointer to point after the
 * word in the string.
 */
static int
getword_str(char *buf, int size, u_char **startpp, u_char *endp) {
        char *cp;
        int c;

        for (cp = buf; *startpp <= endp; ) {
                c = **startpp;
                if (isspace(c) || c == '\0') {
                        if (cp != buf) /* trailing whitespace */
                                break;
                        else { /* leading whitespace */
                                (*startpp)++;
                                continue;
                        }
                }
                (*startpp)++;
                if (cp >= buf+size-1)
                        break;
                *cp++ = (u_char)c;
        }
        *cp = '\0';
        return (cp != buf);
}

/*
 * Get a whitespace delimited number from a string (not file) into buf
 * update the start pointer to point after the number in the string.
 */
static int
getnum_str(u_char **startpp, u_char *endp) {
        int c;
        int n;
        int seendigit = 0;
        int m = 0;

        for (n = 0; *startpp <= endp; ) {
                c = **startpp;
                if (isspace(c) || c == '\0') {
                        if (seendigit) /* trailing whitespace */
                                break;
                        else { /* leading whitespace */
                                (*startpp)++;
                                continue;
                        }
                }
                if (c == ';') {
                        while ((*startpp <= endp) &&
                   ((c = **startpp) != '\n'))
                    (*startpp)++;
                        if (seendigit)
                                break;
                        continue;
                }
                if (!isdigit(c)) {
                        if (c == ')' && seendigit) {
                                (*startpp)--;
                                break;
                        }
            return (-1);
                }
                (*startpp)++;
                n = n * 10 + (c - '0');
                seendigit = 1;
        }
        return (n + m);
}

/*
 * Allocate a resource record buffer & save rr info.
 */
ns_updrec *
res_mkupdrec(int section, const char *dname,
         u_int class, u_int type, u_long ttl) {
    ns_updrec *rrecp = (ns_updrec *)calloc(1, sizeof(ns_updrec));

    if (!rrecp || !(rrecp->r_dname = strdup(dname))) {
        free(rrecp);
        return (NULL);
    }
    rrecp->r_class = (u_int16_t)class;
    rrecp->r_type = (u_int16_t)type;
    rrecp->r_ttl = (u_int32_t)ttl;
    rrecp->r_section = (u_int8_t)section;
    return (rrecp);
}

/*
 * Free a resource record buffer created by res_mkupdrec.
 */
void
res_freeupdrec(ns_updrec *rrecp) {
    /* Note: freeing r_dp is the caller's responsibility. */
    if (rrecp->r_dname != NULL)
        free(rrecp->r_dname);
    free(rrecp);
}