/*

 * 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 <isc/mem.h>

#include <isc/util.h>

#include <dns/ede.h>

#define DNS_EDE_MAGIC  ISC_MAGIC('E', 'D', 'E', '!')

#define DNS_EDE_VALID(v) ISC_MAGIC_VALID(v, DNS_EDE_MAGIC)

static bool

dns__ede_checkandupdateedeused(dns_edectx_t *edectx, uint16_t code) {

  if (edectx->edeused & (1 << code)) {

    return true;

  }

  edectx->edeused |= 1 << code;

  return false;

}

void

dns_ede_add(dns_edectx_t *edectx, uint16_t code, const char *text) {

  REQUIRE(DNS_EDE_VALID(edectx));

  REQUIRE(code < DNS_EDE_MAX_CODE);

  uint16_t becode = htobe16(code);

  dns_ednsopt_t *edns = NULL;

  size_t textlen = 0;

  if (dns__ede_checkandupdateedeused(edectx, code)) {

    isc_log_write(DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER,

            ISC_LOG_DEBUG(1), "ignoring duplicate ede %u %s",

            code, text == NULL ? "(null)" : text);

    return;

  }

  if (edectx->nextede >= DNS_EDE_MAX_ERRORS) {

    isc_log_write(DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER,

            ISC_LOG_DEBUG(1), "too many ede, ignoring %u %s",

            code, text == NULL ? "(null)" : text);

    return;

  }

  INSIST(edectx->ede[edectx->nextede] == NULL);

  isc_log_write(DNS_LOGCATEGORY_RESOLVER, DNS_LOGMODULE_RESOLVER,

          ISC_LOG_DEBUG(1), "set ede: info-code %u extra-text %s",

          code, text == NULL ? "(null)" : text);

  if (text != NULL) {

    textlen = strlen(text);

    if (textlen > DNS_EDE_EXTRATEXT_LEN) {

      isc_log_write(DNS_LOGCATEGORY_RESOLVER,

              DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(1),

              "truncate EDE code %hu text: %s", code,

              text);

      textlen = DNS_EDE_EXTRATEXT_LEN;

    }

  }

  edns = isc_mem_get(edectx->mctx,

         sizeof(*edns) + sizeof(becode) + textlen);

  *edns = (dns_ednsopt_t){

    .code = DNS_OPT_EDE,

    .length = sizeof(becode) + textlen,

    .value = (uint8_t *)edns + sizeof(*edns),

  };

  memmove(edns->value, &becode, sizeof(becode));

  if (textlen > 0) {

    memmove(edns->value + sizeof(becode), text, textlen);

  }

  edectx->ede[edectx->nextede] = edns;

  edectx->nextede++;

}

void

dns_ede_init(isc_mem_t *mctx, dns_edectx_t *edectx) {

  REQUIRE(mctx != NULL);

  /*

   * Memory context is assigned, not attached here,

   * thus there's no detach in dns_ede_reset().

   */

  *edectx = (dns_edectx_t){

    .magic = DNS_EDE_MAGIC,

    .mctx = mctx,

  };

}

void

dns_ede_reset(dns_edectx_t *edectx) {

  REQUIRE(DNS_EDE_VALID(edectx));

  for (size_t i = 0; i < DNS_EDE_MAX_ERRORS; i++) {

    dns_ednsopt_t *edns = edectx->ede[i];

    if (edns == NULL) {

      break;

    }

    isc_mem_put(edectx->mctx, edns, sizeof(*edns) + edns->length);

    edectx->ede[i] = NULL;

  }

  dns_ede_init(edectx->mctx, edectx);

}

void

dns_ede_invalidate(dns_edectx_t *edectx) {

  REQUIRE(DNS_EDE_VALID(edectx));

  dns_ede_reset(edectx);

  edectx->magic = 0;

  edectx->mctx = NULL;

}

void

dns_ede_copy(dns_edectx_t *edectx_to, const dns_edectx_t *edectx_from) {

  REQUIRE(DNS_EDE_VALID(edectx_to));

  REQUIRE(DNS_EDE_VALID(edectx_from));

  if (edectx_to == edectx_from) {

    return;

  }

  for (size_t pos = 0; pos < DNS_EDE_MAX_ERRORS; pos++) {

    uint16_t fromcode;

    if (edectx_from->ede[pos] == NULL) {

      break;

    }

    fromcode = ISC_U8TO16_BE(edectx_from->ede[pos]->value);

    if (dns__ede_checkandupdateedeused(edectx_to, fromcode)) {

      continue;

    }

    if (edectx_to->nextede >= DNS_EDE_MAX_ERRORS) {

      isc_log_write(DNS_LOGCATEGORY_RESOLVER,

              DNS_LOGMODULE_RESOLVER, ISC_LOG_DEBUG(1),

              "too many ede from subfetch");

      break;

    }

    INSIST(edectx_to->ede[edectx_to->nextede] == NULL);

    dns_ednsopt_t *edns = isc_mem_get(

      edectx_to->mctx,

      sizeof(*edns) + edectx_from->ede[pos]->length);

    *edns = (dns_ednsopt_t){

      .code = DNS_OPT_EDE,

      .length = edectx_from->ede[pos]->length,

      .value = (uint8_t *)edns + sizeof(*edns),

    };

    memmove(edns->value, edectx_from->ede[pos]->value,

      edectx_from->ede[pos]->length);

    edectx_to->ede[edectx_to->nextede] = edns;

    edectx_to->nextede++;

  }

}