/*
 * 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, *sp1, *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;
    sp1 = buf + 2*INT16SZ;  /* save pointer to zocount */
    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)))
        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);
}
