/*

 * 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.

 */

#include <inttypes.h>

#include <stdbool.h>

#include <stdlib.h>

#include <isc/buffer.h>

#include <isc/commandline.h>

#include <isc/file.h>

#include <isc/mem.h>

#include <isc/result.h>

#include <isc/string.h>

#include <isc/util.h>

#include <dns/message.h>

#include "fuzz.h"

bool debug = false;

static isc_mem_t *mctx = NULL;

static uint8_t *output = NULL;

static size_t output_len = 1024;

static uint8_t render_buf[64 * 1024 - 1];

int

LLVMFuzzerInitialize(int *argc ISC_ATTR_UNUSED, char ***argv ISC_ATTR_UNUSED) {

  isc_mem_create("fuzz", &mctx);

  output = isc_mem_get(mctx, output_len);

  return 0;

}

static isc_result_t

parse_message(isc_buffer_t *input, dns_message_t **messagep) {

  isc_result_t result;

  dns_message_t *message = NULL;

  dns_message_create(mctx, NULL, NULL, DNS_MESSAGE_INTENTPARSE, &message);

  result = dns_message_parse(message, input, DNS_MESSAGEPARSE_BESTEFFORT);

  if (result == DNS_R_RECOVERABLE) {

    result = ISC_R_SUCCESS;

  }

  if (result == ISC_R_SUCCESS && messagep != NULL) {

    *messagep = message;

  } else {

    dns_message_detach(&message);

  }

  return result;

}

static isc_result_t

print_message(dns_message_t *message) {

  isc_result_t result;

  isc_buffer_t buffer;

  do {

    isc_buffer_init(&buffer, output, output_len);

    result = dns_message_totext(message, &dns_master_style_debug, 0,

              &buffer);

    if (result == ISC_R_NOSPACE) {

      isc_mem_put(mctx, output, output_len);

      output_len *= 2;

      output = isc_mem_get(mctx, output_len);

      continue;

    }

  } while (result == ISC_R_NOSPACE);

  if (debug) {

    fprintf(stderr, "%.*s\n", (int)isc_buffer_usedlength(&buffer),

      output);

  }

  return result;

}

#define CHECKRESULT(r, f)                 \

  {                                 \

    r = (f);                  \

    if (r != ISC_R_SUCCESS) { \

      goto cleanup;     \

    }                         \

  }

static isc_result_t

render_message(dns_message_t **messagep) {

  isc_result_t result;

  dns_message_t *message = *messagep;

  isc_buffer_t buffer;

  dns_compress_t cctx;

  isc_buffer_init(&buffer, render_buf, sizeof(render_buf));

  message->from_to_wire = DNS_MESSAGE_INTENTRENDER;

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

    message->counts[i] = 0;

  }

  dns_compress_init(&cctx, mctx, 0);

  CHECKRESULT(result, dns_message_renderbegin(message, &cctx, &buffer));

  CHECKRESULT(result, dns_message_rendersection(message,

                  DNS_SECTION_QUESTION, 0));

  CHECKRESULT(result,

        dns_message_rendersection(message, DNS_SECTION_ANSWER, 0));

  CHECKRESULT(result, dns_message_rendersection(

            message, DNS_SECTION_AUTHORITY, 0));

  CHECKRESULT(result, dns_message_rendersection(

            message, DNS_SECTION_ADDITIONAL, 0));

  dns_message_renderend(message);

  dns_compress_invalidate(&cctx);

  message->from_to_wire = DNS_MESSAGE_INTENTPARSE;

  dns_message_detach(messagep);

  result = parse_message(&buffer, messagep);

  return result;

cleanup:

  dns_compress_invalidate(&cctx);

  return result;

}

int

LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {

  isc_buffer_t buffer;

  isc_result_t result;

  dns_message_t *message = NULL;

  if (size > 65535) {

    return 0;

  }

  isc_buffer_constinit(&buffer, data, size);

  isc_buffer_add(&buffer, size);

  isc_buffer_setactive(&buffer, size);

  CHECK(parse_message(&buffer, &message));

  CHECK(print_message(message));

  CHECK(render_message(&message));

  CHECK(print_message(message));

cleanup:

  if (message != NULL) {

    dns_message_detach(&message);

  }

  return 0;

}