/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * 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 ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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.
 */

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

#include "port_before.h"

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/time.h>

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

#include <errno.h>
#include <limits.h>
#include <netdb.h>
#include <res_update.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <isc/list.h>
#include <resolv.h>

#include "port_after.h"
#include "res_private.h"

/*%
 * Separate a linked list of records into groups so that all records
 * in a group will belong to a single zone on the nameserver.
 * Create a dynamic update packet for each zone and send it to the
 * nameservers for that zone, and await answer.
 * Abort if error occurs in updating any zone.
 * Return the number of zones updated on success, < 0 on error.
 *
 * On error, caller must deal with the unsynchronized zones
 * eg. an A record might have been successfully added to the forward
 * zone but the corresponding PTR record would be missing if error
 * was encountered while updating the reverse zone.
 */

struct zonegrp {
        char                    z_origin[MAXDNAME];
        ns_class                z_class;
        union res_sockaddr_union z_nsaddrs[MAXNS];
        int                     z_nscount;
        int                     z_flags;
        LIST(ns_updrec)         z_rrlist;
        LINK(struct zonegrp)    z_link;
};

#define ZG_F_ZONESECTADDED      0x0001

/* Forward. */

static void     res_dprintf(const char *, ...) ISC_FORMAT_PRINTF(1, 2);

/* Macros. */

#define DPRINTF(x) do {\
                int save_errno = errno; \
                if ((statp->options & RES_DEBUG) != 0U) res_dprintf x; \
                errno = save_errno; \
        } while (0)

/* Public. */

int
res_nupdate(res_state statp, ns_updrec *rrecp_in, ns_tsig_key *key) {
        ns_updrec *rrecp;
        u_char answer[PACKETSZ];
        u_char *packet;
        struct zonegrp *zptr, tgrp;
        LIST(struct zonegrp) zgrps;
        int nzones = 0, nscount = 0, n;
        union res_sockaddr_union nsaddrs[MAXNS];

        packet = malloc(NS_MAXMSG);
        if (packet == NULL) {
                DPRINTF(("malloc failed"));
                return (0);
        }
        /* Thread all of the updates onto a list of groups. */
        INIT_LIST(zgrps);
        memset(&tgrp, 0, sizeof (tgrp));
        for (rrecp = rrecp_in; rrecp;
             rrecp = LINKED(rrecp, r_link) ? NEXT(rrecp, r_link) : NULL) {
                int nscnt;
                /* Find the origin for it if there is one. */
                tgrp.z_class = rrecp->r_class;
                nscnt = res_findzonecut2(statp, rrecp->r_dname, tgrp.z_class,
                                         RES_EXHAUSTIVE, tgrp.z_origin,
                                         sizeof tgrp.z_origin,
                                         tgrp.z_nsaddrs, MAXNS);
                if (nscnt <= 0) {
                        DPRINTF(("res_findzonecut failed (%d)", nscnt));
                        goto done;
                }
                tgrp.z_nscount = nscnt;
                /* Find the group for it if there is one. */
                for (zptr = HEAD(zgrps); zptr != NULL; zptr = NEXT(zptr, z_link))
                        if (ns_samename(tgrp.z_origin, zptr->z_origin) == 1 &&
                            tgrp.z_class == zptr->z_class)
                                break;
                /* Make a group for it if there isn't one. */
                if (zptr == NULL) {
                        zptr = malloc(sizeof *zptr);
                        if (zptr == NULL) {
                                DPRINTF(("malloc failed"));
                                goto done;
                        }
                        *zptr = tgrp;
                        zptr->z_flags = 0;
                        INIT_LINK(zptr, z_link);
                        INIT_LIST(zptr->z_rrlist);
                        APPEND(zgrps, zptr, z_link);
                }
                /* Thread this rrecp onto the right group. */
                APPEND(zptr->z_rrlist, rrecp, r_glink);
        }

        for (zptr = HEAD(zgrps); zptr != NULL; zptr = NEXT(zptr, z_link)) {
                /* Construct zone section and prepend it. */
                rrecp = res_mkupdrec(ns_s_zn, zptr->z_origin,
                                     zptr->z_class, ns_t_soa, 0);
                if (rrecp == NULL) {
                        DPRINTF(("res_mkupdrec failed"));
                        goto done;
                }
                PREPEND(zptr->z_rrlist, rrecp, r_glink);
                zptr->z_flags |= ZG_F_ZONESECTADDED;

                /* Marshall the update message. */
                n = res_nmkupdate(statp, HEAD(zptr->z_rrlist),
                                  packet, NS_MAXMSG);
                DPRINTF(("res_mkupdate -> %d", n));
                if (n < 0)
                        goto done;

                /* Temporarily replace the resolver's nameserver set. */
                nscount = res_getservers(statp, nsaddrs, MAXNS);
                res_setservers(statp, zptr->z_nsaddrs, zptr->z_nscount);

                /* Send the update and remember the result. */
                if (key != NULL)
                        n = res_nsendsigned(statp, packet, n, key,
                                            answer, sizeof answer);
                else
                        n = res_nsend(statp, packet, n, answer, sizeof answer);
                if (n < 0) {
                        DPRINTF(("res_nsend: send error, n=%d (%s)\n",
                                 n, strerror(errno)));
                        goto done;
                }
                if (((HEADER *)answer)->rcode == NOERROR)
                        nzones++;

                /* Restore resolver's nameserver set. */
                res_setservers(statp, nsaddrs, nscount);
                nscount = 0;
        }
 done:
        while (!EMPTY(zgrps)) {
                zptr = HEAD(zgrps);
                if ((zptr->z_flags & ZG_F_ZONESECTADDED) != 0)
                        res_freeupdrec(HEAD(zptr->z_rrlist));
                UNLINK(zgrps, zptr, z_link);
                free(zptr);
        }
        if (nscount != 0)
                res_setservers(statp, nsaddrs, nscount);

        free(packet);
        return (nzones);
}

/* Private. */

static void
res_dprintf(const char *fmt, ...) {
        va_list ap;

        va_start(ap, fmt);
        fputs(";; res_nupdate: ", stderr);
        vfprintf(stderr, fmt, ap);
        fputc('\n', stderr);
        va_end(ap);
}