/* Test __libc_res_nsend buffer mismanagement, basic TCP coverage.

   Copyright (C) 2016-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <errno.h>

#include <netdb.h>

#include <resolv.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <support/check.h>

#include <support/check_nss.h>

#include <support/resolv_test.h>

#include <support/xthread.h>

#include <support/xmemstream.h>

static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;

static int initial_address_count = 1;

static int subsequent_address_count = 2000;

static int response_number = 0;

static void

response (const struct resolv_response_context *ctx,

          struct resolv_response_builder *b,

          const char *qname, uint16_t qclass, uint16_t qtype)

{

  TEST_VERIFY_EXIT (qname != NULL);

  /* If not using TCP, just force its use.  */

  if (!ctx->tcp)

    {

      struct resolv_response_flags flags = {.tc = true};

      resolv_response_init (b, flags);

      resolv_response_add_question (b, qname, qclass, qtype);

      return;

    }

  struct resolv_response_flags flags = {};

  resolv_response_init (b, flags);

  resolv_response_add_question (b, qname, qclass, qtype);

  resolv_response_section (b, ns_s_an);

  /* The number of addresses (in the additional section) for the name

     server record (in the authoritative section).  */

  int address_count;

  xpthread_mutex_lock (&lock);

  ++response_number;

  if (response_number == 1)

    address_count = initial_address_count;

  else if (response_number == 2)

    {

      address_count = 0;

      resolv_response_drop (b);

      resolv_response_close (b);

    }

  else

    address_count = subsequent_address_count;

  xpthread_mutex_unlock (&lock);

  /* Only add the address record to the answer section if we requested

     any name server addresses.  */

  if (address_count > 0)

    {

      resolv_response_open_record (b, qname, qclass, qtype, 0);

      switch (qtype)

        {

        case T_A:

          {

            char ipv4[4] = {10, response_number >> 8, response_number, 0};

            ipv4[3] = 2 * ctx->tcp + 4 * ctx->server_index;

            resolv_response_add_data (b, &ipv4, sizeof (ipv4));

          }

          break;

        case T_AAAA:

          {

            char ipv6[16]

              = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0,

                 response_number >> 8, response_number, 0, 0};

            ipv6[15] = 2 * ctx->tcp + 4 * ctx->server_index;

            resolv_response_add_data (b, &ipv6, sizeof (ipv6));

          }

          break;

        default:

          support_record_failure ();

          printf ("error: unexpected QTYPE: %s/%u/%u\n",

                  qname, qclass, qtype);

        }

      resolv_response_close_record (b);

      /* Add the name server record.  */

      resolv_response_section (b, ns_s_ns);

      resolv_response_open_record (b, "example", C_IN, T_NS, 0);

      resolv_response_add_name (b, "ns.example");

      resolv_response_close_record (b);

      /* Increase the response size with name server addresses.  These

         addresses are not copied out of nss_dns, and thus do not

         trigger getaddrinfo retries with a larger buffer, making

         testing more predictable.  */

      resolv_response_section (b, ns_s_ar);

      for (int i = 1; i <= address_count; ++i)

        {

          resolv_response_open_record (b, "ns.example", qclass, qtype, 0);

          switch (qtype)

            {

            case T_A:

              {

                char ipv4[4] = {response_number, i >> 8, i, 0};

                ipv4[3] = 2 * ctx->tcp + 4 * ctx->server_index;

                resolv_response_add_data (b, &ipv4, sizeof (ipv4));

              }

              break;

            case T_AAAA:

              {

                char ipv6[16]

                  = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0,

                     response_number >> 8, response_number,

                     i >> 8, i, 0, 0};

                ipv6[15] = 2 * ctx->tcp + 4 * ctx->server_index;

                resolv_response_add_data (b, &ipv6, sizeof (ipv6));

              }

              break;

            default:

              support_record_failure ();

              printf ("error: unexpected QTYPE: %s/%u/%u\n",

                      qname, qclass, qtype);

            }

          resolv_response_close_record (b);

        }

    }

}

static char *

expected_result (unsigned port, unsigned response_number)

{

  struct xmemstream mem;

  xopen_memstream (&mem;;

  /* We fail the second TCP query to the first server by closing the

     connection immediately, without returning any data.  This should

     cause failover to the second server.  */

  int server_index = 1;

  fprintf (mem.out, "address: STREAM/TCP 10.%u.%u.%u %u\n",

           (response_number >> 8) & 0xff, response_number & 0xff,

           2 + 4 * server_index, port);

  fprintf (mem.out, "address: STREAM/TCP 2001:db8::%x:%x %u\n",

           (response_number + 1) & 0xffff,

           2 + 4 * server_index, port);

  xfclose_memstream (&mem;;

  return mem.buffer;

}

static void

test_different_sizes (void)

{

  struct addrinfo hints =

    {

      .ai_family = AF_UNSPEC,

      .ai_socktype = SOCK_STREAM,

      .ai_protocol = IPPROTO_TCP,

    };

  struct addrinfo *ai;

  char *expected;

  int ret;

  /* This magic number produces a response size close to 2048

     bytes.  */

  initial_address_count = 124;

  response_number = 0;

  ret = getaddrinfo ("www.example", "80", &hints, &ai;;

  expected = expected_result (80, 3);

  check_addrinfo ("www.example:80", ai, ret, expected);

  if (ret == 0)

    freeaddrinfo (ai);

  free (expected);

  response_number = 0;

  ret = getaddrinfo ("www123.example", "80", &hints, &ai;;

  if (ret == 0)

    freeaddrinfo (ai);

  response_number = 0;

  ret = getaddrinfo ("www1234.example", "80", &hints, &ai;;

  if (ret == 0)

    freeaddrinfo (ai);

  response_number = 0;

  ret = getaddrinfo ("www12345.example", "80", &hints, &ai;;

  if (ret == 0)

    freeaddrinfo (ai);

}

static int

do_test (void)

{

  struct resolv_test *obj = resolv_test_start

    ((struct resolv_redirect_config)

     {

       .response_callback = response

     });

  test_different_sizes ();

  _res.options |= RES_SNGLKUP;

  test_different_sizes ();

  _res.options |= RES_SNGLKUPREOP;

  test_different_sizes ();

  resolv_test_end (obj);

  return 0;

}

#include <support/test-driver.c>