/*

 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")

 *

 * SPDX-License-Identifier: MPL-2.0

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, you can obtain one at https://mozilla.org/MPL/2.0/.

 *

 * See the COPYRIGHT file distributed with this work for additional

 * information regarding copyright ownership.

 */

/*! \file */

#include <inttypes.h>

#include <stdbool.h>

#include <stdlib.h>

#include <isc/buffer.h>

#include <isc/file.h>

#include <isc/mem.h>

#include <isc/result.h>

#include <isc/string.h>

#include <isc/util.h>

#include <dns/db.h>

#include <dns/diff.h>

#include <dns/log.h>

#include <dns/rdataclass.h>

#include <dns/rdatalist.h>

#include <dns/rdataset.h>

#include <dns/rdatastruct.h>

#include <dns/rdatatype.h>

#include <dns/time.h>

#define CHECK(op)                            \

  do {                                 \

    result = (op);               \

    if (result != ISC_R_SUCCESS) \

      goto failure;        \

  } while (0)

#define DIFF_COMMON_LOGARGS \

  dns_lctx, DNS_LOGCATEGORY_GENERAL, DNS_LOGMODULE_DIFF

static dns_rdatatype_t

rdata_covers(dns_rdata_t *rdata) {

  return (rdata->type == dns_rdatatype_rrsig ? dns_rdata_covers(rdata)

               : 0);

}

isc_result_t

dns_difftuple_create(isc_mem_t *mctx, dns_diffop_t op, const dns_name_t *name,

         dns_ttl_t ttl, dns_rdata_t *rdata, dns_difftuple_t **tp) {

  dns_difftuple_t *t;

  unsigned int size;

  unsigned char *datap;

  REQUIRE(tp != NULL && *tp == NULL);

  /*

   * Create a new tuple.  The variable-size wire-format name data and

   * rdata immediately follow the dns_difftuple_t structure

   * in memory.

   */

  size = sizeof(*t) + name->length + rdata->length;

  t = isc_mem_allocate(mctx, size);

  t->mctx = NULL;

  isc_mem_attach(mctx, &t->mctx);

  t->op = op;

  datap = (unsigned char *)(t + 1);

  memmove(datap, name->ndata, name->length);

  dns_name_init(&t->name, NULL);

  dns_name_clone(name, &t->name);

  t->name.ndata = datap;

  datap += name->length;

  t->ttl = ttl;

  dns_rdata_init(&t->rdata);

  dns_rdata_clone(rdata, &t->rdata);

  if (rdata->data != NULL) {

    memmove(datap, rdata->data, rdata->length);

    t->rdata.data = datap;

    datap += rdata->length;

  } else {

    t->rdata.data = NULL;

    INSIST(rdata->length == 0);

  }

  ISC_LINK_INIT(&t->rdata, link);

  ISC_LINK_INIT(t, link);

  t->magic = DNS_DIFFTUPLE_MAGIC;

  INSIST(datap == (unsigned char *)t + size);

  *tp = t;

  return (ISC_R_SUCCESS);

}

void

dns_difftuple_free(dns_difftuple_t **tp) {

  dns_difftuple_t *t = *tp;

  *tp = NULL;

  isc_mem_t *mctx;

  REQUIRE(DNS_DIFFTUPLE_VALID(t));

  dns_name_invalidate(&t->name);

  t->magic = 0;

  mctx = t->mctx;

  isc_mem_free(mctx, t);

  isc_mem_detach(&mctx);

}

isc_result_t

dns_difftuple_copy(dns_difftuple_t *orig, dns_difftuple_t **copyp) {

  return (dns_difftuple_create(orig->mctx, orig->op, &orig->name,

             orig->ttl, &orig->rdata, copyp));

}

void

dns_diff_init(isc_mem_t *mctx, dns_diff_t *diff) {

  diff->mctx = mctx;

  ISC_LIST_INIT(diff->tuples);

  diff->magic = DNS_DIFF_MAGIC;

}

void

dns_diff_clear(dns_diff_t *diff) {

  dns_difftuple_t *t;

  REQUIRE(DNS_DIFF_VALID(diff));

  while ((t = ISC_LIST_HEAD(diff->tuples)) != NULL) {

    ISC_LIST_UNLINK(diff->tuples, t, link);

    dns_difftuple_free(&t);

  }

  ENSURE(ISC_LIST_EMPTY(diff->tuples));

}

void

dns_diff_append(dns_diff_t *diff, dns_difftuple_t **tuplep) {

  ISC_LIST_APPEND(diff->tuples, *tuplep, link);

  *tuplep = NULL;

}

/* XXX this is O(N) */

void

dns_diff_appendminimal(dns_diff_t *diff, dns_difftuple_t **tuplep) {

  dns_difftuple_t *ot, *next_ot;

  REQUIRE(DNS_DIFF_VALID(diff));

  REQUIRE(DNS_DIFFTUPLE_VALID(*tuplep));

  /*

   * Look for an existing tuple with the same owner name,

   * rdata, and TTL.   If we are doing an addition and find a

   * deletion or vice versa, remove both the old and the

   * new tuple since they cancel each other out (assuming

   * that we never delete nonexistent data or add existing

   * data).

   *

   * If we find an old update of the same kind as

   * the one we are doing, there must be a programming

   * error.  We report it but try to continue anyway.

   */

  for (ot = ISC_LIST_HEAD(diff->tuples); ot != NULL; ot = next_ot) {

    next_ot = ISC_LIST_NEXT(ot, link);

    if (dns_name_caseequal(&ot->name, &(*tuplep)->name) &&

        dns_rdata_compare(&ot->rdata, &(*tuplep)->rdata) == 0 &&

        ot->ttl == (*tuplep)->ttl)

    {

      ISC_LIST_UNLINK(diff->tuples, ot, link);

      if ((*tuplep)->op == ot->op) {

        UNEXPECTED_ERROR("unexpected non-minimal diff");

      } else {

        dns_difftuple_free(tuplep);

      }

      dns_difftuple_free(&ot);

      break;

    }

  }

  if (*tuplep != NULL) {

    ISC_LIST_APPEND(diff->tuples, *tuplep, link);

    *tuplep = NULL;

  }

}

static isc_stdtime_t

setresign(dns_rdataset_t *modified) {

  dns_rdata_t rdata = DNS_RDATA_INIT;

  dns_rdata_rrsig_t sig;

  int64_t when;

  isc_result_t result;

  result = dns_rdataset_first(modified);

  INSIST(result == ISC_R_SUCCESS);

  dns_rdataset_current(modified, &rdata);

  (void)dns_rdata_tostruct(&rdata, &sig, NULL);

  if ((rdata.flags & DNS_RDATA_OFFLINE) != 0) {

    when = 0;

  } else {

    when = dns_time64_from32(sig.timeexpire);

  }

  dns_rdata_reset(&rdata);

  result = dns_rdataset_next(modified);

  while (result == ISC_R_SUCCESS) {

    dns_rdataset_current(modified, &rdata);

    (void)dns_rdata_tostruct(&rdata, &sig, NULL);

    if ((rdata.flags & DNS_RDATA_OFFLINE) != 0) {

      goto next_rr;

    }

    if (when == 0 || dns_time64_from32(sig.timeexpire) < when) {

      when = dns_time64_from32(sig.timeexpire);

    }

  next_rr:

    dns_rdata_reset(&rdata);

    result = dns_rdataset_next(modified);

  }

  INSIST(result == ISC_R_NOMORE);

  return ((isc_stdtime_t)when);

}

static void

getownercase(dns_rdataset_t *rdataset, dns_name_t *name) {

  if (dns_rdataset_isassociated(rdataset)) {

    dns_rdataset_getownercase(rdataset, name);

  }

}

static void

setownercase(dns_rdataset_t *rdataset, const dns_name_t *name) {

  if (dns_rdataset_isassociated(rdataset)) {

    dns_rdataset_setownercase(rdataset, name);

  }

}

static isc_result_t

diff_apply(dns_diff_t *diff, dns_db_t *db, dns_dbversion_t *ver, bool warn) {

  dns_difftuple_t *t;

  dns_dbnode_t *node = NULL;

  isc_result_t result;

  char namebuf[DNS_NAME_FORMATSIZE];

  char typebuf[DNS_RDATATYPE_FORMATSIZE];

  char classbuf[DNS_RDATACLASS_FORMATSIZE];

  REQUIRE(DNS_DIFF_VALID(diff));

  REQUIRE(DNS_DB_VALID(db));

  t = ISC_LIST_HEAD(diff->tuples);

  while (t != NULL) {

    dns_name_t *name;

    INSIST(node == NULL);

    name = &t->name;

    /*

     * Find the node.

     * We create the node if it does not exist.

     * This will cause an empty node to be created if the diff

     * contains a deletion of an RR at a nonexistent name,

     * but such diffs should never be created in the first

     * place.

     */

    while (t != NULL && dns_name_equal(&t->name, name)) {

      dns_rdatatype_t type, covers;

      dns_diffop_t op;

      dns_rdatalist_t rdl;

      dns_rdataset_t rds;

      dns_rdataset_t ardataset;

      unsigned int options;

      op = t->op;

      type = t->rdata.type;

      covers = rdata_covers(&t->rdata);

      /*

       * Collect a contiguous set of updates with

       * the same operation (add/delete) and RR type

       * into a single rdatalist so that the

       * database rrset merging/subtraction code

       * can work more efficiently than if each

       * RR were merged into / subtracted from

       * the database separately.

       *

       * This is done by linking rdata structures from the

       * diff into "rdatalist".  This uses the rdata link

       * field, not the diff link field, so the structure

       * of the diff itself is not affected.

       */

      dns_rdatalist_init(&rdl);

      rdl.type = type;

      rdl.covers = covers;

      rdl.rdclass = t->rdata.rdclass;

      rdl.ttl = t->ttl;

      node = NULL;

      if (type != dns_rdatatype_nsec3 &&

          covers != dns_rdatatype_nsec3)

      {

        CHECK(dns_db_findnode(db, name, true, &node));

      } else {

        CHECK(dns_db_findnsec3node(db, name, true,

                 &node));

      }

      while (t != NULL && dns_name_equal(&t->name, name) &&

             t->op == op && t->rdata.type == type &&

             rdata_covers(&t->rdata) == covers)

      {

        /*

         * Remember the add name for

         * dns_rdataset_setownercase.

         */

        name = &t->name;

        if (t->ttl != rdl.ttl && warn) {

          dns_name_format(name, namebuf,

              sizeof(namebuf));

          dns_rdatatype_format(t->rdata.type,

                   typebuf,

                   sizeof(typebuf));

          dns_rdataclass_format(t->rdata.rdclass,

                    classbuf,

                    sizeof(classbuf));

          isc_log_write(DIFF_COMMON_LOGARGS,

                  ISC_LOG_WARNING,

                  "'%s/%s/%s': TTL differs "

                  "in "

                  "rdataset, adjusting "

                  "%lu -> %lu",

                  namebuf, typebuf,

                  classbuf,

                  (unsigned long)t->ttl,

                  (unsigned long)rdl.ttl);

        }

        ISC_LIST_APPEND(rdl.rdata, &t->rdata, link);

        t = ISC_LIST_NEXT(t, link);

      }

      /*

       * Convert the rdatalist into a rdataset.

       */

      dns_rdataset_init(&rds);

      dns_rdataset_init(&ardataset);

      dns_rdatalist_tordataset(&rdl, &rds);

      rds.trust = dns_trust_ultimate;

      /*

       * Merge the rdataset into the database.

       */

      switch (op) {

      case DNS_DIFFOP_ADD:

      case DNS_DIFFOP_ADDRESIGN:

        options = DNS_DBADD_MERGE | DNS_DBADD_EXACT |

            DNS_DBADD_EXACTTTL;

        result = dns_db_addrdataset(db, node, ver, 0,

                  &rds, options,

                  &ardataset);

        break;

      case DNS_DIFFOP_DEL:

      case DNS_DIFFOP_DELRESIGN:

        options = DNS_DBSUB_EXACT | DNS_DBSUB_WANTOLD;

        result = dns_db_subtractrdataset(db, node, ver,

                 &rds, options,

                 &ardataset);

        break;

      default:

        UNREACHABLE();

      }

      if (result == ISC_R_SUCCESS) {

        if (rds.type == dns_rdatatype_rrsig &&

            (op == DNS_DIFFOP_DELRESIGN ||

             op == DNS_DIFFOP_ADDRESIGN))

        {

          isc_stdtime_t resign;

          resign = setresign(&ardataset);

          dns_db_setsigningtime(db, &ardataset,

                    resign);

        }

        if (op == DNS_DIFFOP_ADD ||

            op == DNS_DIFFOP_ADDRESIGN)

        {

          setownercase(&ardataset, name);

        }

        if (op == DNS_DIFFOP_DEL ||

            op == DNS_DIFFOP_DELRESIGN)

        {

          getownercase(&ardataset, name);

        }

      } else if (result == DNS_R_UNCHANGED) {

        /*

         * This will not happen when executing a

         * dynamic update, because that code will

         * generate strictly minimal diffs.

         * It may happen when receiving an IXFR

         * from a server that is not as careful.

         * Issue a warning and continue.

         */

        if (warn) {

          dns_name_format(dns_db_origin(db),

              namebuf,

              sizeof(namebuf));

          dns_rdataclass_format(dns_db_class(db),

                    classbuf,

                    sizeof(classbuf));

          isc_log_write(DIFF_COMMON_LOGARGS,

                  ISC_LOG_WARNING,

                  "%s/%s: dns_diff_apply: "

                  "update with no effect",

                  namebuf, classbuf);

        }

        if (op == DNS_DIFFOP_ADD ||

            op == DNS_DIFFOP_ADDRESIGN)

        {

          setownercase(&ardataset, name);

        }

        if (op == DNS_DIFFOP_DEL ||

            op == DNS_DIFFOP_DELRESIGN)

        {

          getownercase(&ardataset, name);

        }

      } else if (result == DNS_R_NXRRSET) {

        /*

         * OK.

         */

        if (op == DNS_DIFFOP_DEL ||

            op == DNS_DIFFOP_DELRESIGN)

        {

          getownercase(&ardataset, name);

        }

        if (dns_rdataset_isassociated(&ardataset)) {

          dns_rdataset_disassociate(&ardataset);

        }

      } else {

        if (dns_rdataset_isassociated(&ardataset)) {

          dns_rdataset_disassociate(&ardataset);

        }

        CHECK(result);

      }

      dns_db_detachnode(db, &node);

      if (dns_rdataset_isassociated(&ardataset)) {

        dns_rdataset_disassociate(&ardataset);

      }

    }

  }

  return (ISC_R_SUCCESS);

failure:

  if (node != NULL) {

    dns_db_detachnode(db, &node);

  }

  return (result);

}

isc_result_t

dns_diff_apply(dns_diff_t *diff, dns_db_t *db, dns_dbversion_t *ver) {

  return (diff_apply(diff, db, ver, true));

}

isc_result_t

dns_diff_applysilently(dns_diff_t *diff, dns_db_t *db, dns_dbversion_t *ver) {

  return (diff_apply(diff, db, ver, false));

}

/* XXX this duplicates lots of code in diff_apply(). */

isc_result_t

dns_diff_load(dns_diff_t *diff, dns_addrdatasetfunc_t addfunc,

        void *add_private) {

  dns_difftuple_t *t;

  isc_result_t result;

  REQUIRE(DNS_DIFF_VALID(diff));

  t = ISC_LIST_HEAD(diff->tuples);

  while (t != NULL) {

    dns_name_t *name;

    name = &t->name;

    while (t != NULL && dns_name_caseequal(&t->name, name)) {

      dns_rdatatype_t type, covers;

      dns_diffop_t op;

      dns_rdatalist_t rdl;

      dns_rdataset_t rds;

      op = t->op;

      type = t->rdata.type;

      covers = rdata_covers(&t->rdata);

      dns_rdatalist_init(&rdl);

      rdl.type = type;

      rdl.covers = covers;

      rdl.rdclass = t->rdata.rdclass;

      rdl.ttl = t->ttl;

      while (t != NULL &&

             dns_name_caseequal(&t->name, name) &&

             t->op == op && t->rdata.type == type &&

             rdata_covers(&t->rdata) == covers)

      {

        ISC_LIST_APPEND(rdl.rdata, &t->rdata, link);

        t = ISC_LIST_NEXT(t, link);

      }

      /*

       * Convert the rdatalist into a rdataset.

       */

      dns_rdataset_init(&rds);

      dns_rdatalist_tordataset(&rdl, &rds);

      rds.trust = dns_trust_ultimate;

      INSIST(op == DNS_DIFFOP_ADD);

      result = (*addfunc)(add_private, name,

              &rds DNS__DB_FILELINE);

      if (result == DNS_R_UNCHANGED) {

        isc_log_write(DIFF_COMMON_LOGARGS,

                ISC_LOG_WARNING,

                "dns_diff_load: "

                "update with no effect");

      } else if (result == ISC_R_SUCCESS ||

           result == DNS_R_NXRRSET)

      {

        /*

         * OK.

         */

      } else {

        CHECK(result);

      }

    }

  }

  result = ISC_R_SUCCESS;

failure:

  return (result);

}

/*

 * XXX uses qsort(); a merge sort would be more natural for lists,

 * and perhaps safer wrt thread stack overflow.

 */

isc_result_t

dns_diff_sort(dns_diff_t *diff, dns_diff_compare_func *compare) {

  unsigned int length = 0;

  unsigned int i;

  dns_difftuple_t **v;

  dns_difftuple_t *p;

  REQUIRE(DNS_DIFF_VALID(diff));

  for (p = ISC_LIST_HEAD(diff->tuples); p != NULL;

       p = ISC_LIST_NEXT(p, link))

  {

    length++;

  }

  if (length == 0) {

    return (ISC_R_SUCCESS);

  }

  v = isc_mem_get(diff->mctx, length * sizeof(dns_difftuple_t *));

  for (i = 0; i < length; i++) {

    p = ISC_LIST_HEAD(diff->tuples);

    v[i] = p;

    ISC_LIST_UNLINK(diff->tuples, p, link);

  }

  INSIST(ISC_LIST_HEAD(diff->tuples) == NULL);

  qsort(v, length, sizeof(v[0]), compare);

  for (i = 0; i < length; i++) {

    ISC_LIST_APPEND(diff->tuples, v[i], link);

  }

  isc_mem_put(diff->mctx, v, length * sizeof(dns_difftuple_t *));

  return (ISC_R_SUCCESS);

}

/*

 * Create an rdataset containing the single RR of the given

 * tuple.  The caller must allocate the rdata, rdataset and

 * an rdatalist structure for it to refer to.

 */

static void

diff_tuple_tordataset(dns_difftuple_t *t, dns_rdata_t *rdata,

          dns_rdatalist_t *rdl, dns_rdataset_t *rds) {

  REQUIRE(DNS_DIFFTUPLE_VALID(t));

  REQUIRE(rdl != NULL);

  REQUIRE(rds != NULL);

  dns_rdatalist_init(rdl);

  rdl->type = t->rdata.type;

  rdl->rdclass = t->rdata.rdclass;

  rdl->ttl = t->ttl;

  dns_rdataset_init(rds);

  ISC_LINK_INIT(rdata, link);

  dns_rdata_clone(&t->rdata, rdata);

  ISC_LIST_APPEND(rdl->rdata, rdata, link);

  dns_rdatalist_tordataset(rdl, rds);

}

isc_result_t

dns_diff_print(dns_diff_t *diff, FILE *file) {

  isc_result_t result;

  dns_difftuple_t *t;

  char *mem = NULL;

  unsigned int size = 2048;

  const char *op = NULL;

  REQUIRE(DNS_DIFF_VALID(diff));

  mem = isc_mem_get(diff->mctx, size);

  for (t = ISC_LIST_HEAD(diff->tuples); t != NULL;

       t = ISC_LIST_NEXT(t, link))

  {

    isc_buffer_t buf;

    isc_region_t r;

    dns_rdatalist_t rdl;

    dns_rdataset_t rds;

    dns_rdata_t rd = DNS_RDATA_INIT;

    diff_tuple_tordataset(t, &rd, &rdl, &rds);

  again:

    isc_buffer_init(&buf, mem, size);

    result = dns_rdataset_totext(&rds, &t->name, false, false,

               &buf);

    if (result == ISC_R_NOSPACE) {

      isc_mem_put(diff->mctx, mem, size);

      size += 1024;

      mem = isc_mem_get(diff->mctx, size);

      goto again;

    }

    if (result != ISC_R_SUCCESS) {

      goto cleanup;

    }

    /*

     * Get rid of final newline.

     */

    INSIST(buf.used >= 1 &&

           ((char *)buf.base)[buf.used - 1] == '\n');

    buf.used--;

    isc_buffer_usedregion(&buf, &r);

    switch (t->op) {

    case DNS_DIFFOP_EXISTS:

      op = "exists";

      break;

    case DNS_DIFFOP_ADD:

      op = "add";

      break;

    case DNS_DIFFOP_DEL:

      op = "del";

      break;

    case DNS_DIFFOP_ADDRESIGN:

      op = "add re-sign";

      break;

    case DNS_DIFFOP_DELRESIGN:

      op = "del re-sign";

      break;

    }

    if (file != NULL) {

      fprintf(file, "%s %.*s\n", op, (int)r.length,

        (char *)r.base);

    } else {

      isc_log_write(DIFF_COMMON_LOGARGS, ISC_LOG_DEBUG(7),

              "%s %.*s", op, (int)r.length,

              (char *)r.base);

    }

  }

  result = ISC_R_SUCCESS;

cleanup:

  if (mem != NULL) {

    isc_mem_put(diff->mctx, mem, size);

  }

  return (result);

}