resolv/tst-bug18665-tcp.c

   1 /* Test __libc_res_nsend buffer mismanagement, basic TCP coverage.
   2    Copyright (C) 2016-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <errno.h>
  20 #include <netdb.h>
  21 #include <resolv.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <support/check.h>
  26 #include <support/check_nss.h>
  27 #include <support/resolv_test.h>
  28 #include <support/xthread.h>
  29 #include <support/xmemstream.h>
  30
  31 static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
  32
  33 static int initial_address_count = 1;
  34 static int subsequent_address_count = 2000;
  35 static int response_number = 0;
  36
  37 static void
  38 response (const struct resolv_response_context *ctx,
  39           struct resolv_response_builder *b,
  40           const char *qname, uint16_t qclass, uint16_t qtype)
  41 {
  42   TEST_VERIFY_EXIT (qname != NULL);
  43
  44   /* If not using TCP, just force its use.  */
  45   if (!ctx->tcp)
  46     {
  47       struct resolv_response_flags flags = {.tc = true};
  48       resolv_response_init (b, flags);
  49       resolv_response_add_question (b, qname, qclass, qtype);
  50       return;
  51     }
  52
  53   struct resolv_response_flags flags = {};
  54   resolv_response_init (b, flags);
  55   resolv_response_add_question (b, qname, qclass, qtype);
  56
  57   resolv_response_section (b, ns_s_an);
  58
  59   /* The number of addresses (in the additional section) for the name
  60      server record (in the authoritative section).  */
  61   int address_count;
  62   xpthread_mutex_lock (&lock);
  63   ++response_number;
  64   if (response_number == 1)
  65     address_count = initial_address_count;
  66   else if (response_number == 2)
  67     {
  68       address_count = 0;
  69       resolv_response_drop (b);
  70       resolv_response_close (b);
  71     }
  72   else
  73     address_count = subsequent_address_count;
  74   xpthread_mutex_unlock (&lock);
  75
  76   /* Only add the address record to the answer section if we requested
  77      any name server addresses.  */
  78   if (address_count > 0)
  79     {
  80       resolv_response_open_record (b, qname, qclass, qtype, 0);
  81       switch (qtype)
  82         {
  83         case T_A:
  84           {
  85             char ipv4[4] = {10, response_number >> 8, response_number, 0};
  86             ipv4[3] = 2 * ctx->tcp + 4 * ctx->server_index;
  87             resolv_response_add_data (b, &ipv4, sizeof (ipv4));
  88           }
  89           break;
  90         case T_AAAA:
  91           {
  92             char ipv6[16]
  93               = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0,
  94                  response_number >> 8, response_number, 0, 0};
  95             ipv6[15] = 2 * ctx->tcp + 4 * ctx->server_index;
  96             resolv_response_add_data (b, &ipv6, sizeof (ipv6));
  97           }
  98           break;
  99         default:
 100           support_record_failure ();
 101           printf ("error: unexpected QTYPE: %s/%u/%u\n",
 102                   qname, qclass, qtype);
 103         }
 104       resolv_response_close_record (b);
 105
 106       /* Add the name server record.  */
 107       resolv_response_section (b, ns_s_ns);
 108       resolv_response_open_record (b, "example", C_IN, T_NS, 0);
 109       resolv_response_add_name (b, "ns.example");
 110       resolv_response_close_record (b);
 111
 112       /* Increase the response size with name server addresses.  These
 113          addresses are not copied out of nss_dns, and thus do not
 114          trigger getaddrinfo retries with a larger buffer, making
 115          testing more predictable.  */
 116       resolv_response_section (b, ns_s_ar);
 117       for (int i = 1; i <= address_count; ++i)
 118         {
 119           resolv_response_open_record (b, "ns.example", qclass, qtype, 0);
 120           switch (qtype)
 121             {
 122             case T_A:
 123               {
 124                 char ipv4[4] = {response_number, i >> 8, i, 0};
 125                 ipv4[3] = 2 * ctx->tcp + 4 * ctx->server_index;
 126                 resolv_response_add_data (b, &ipv4, sizeof (ipv4));
 127               }
 128               break;
 129             case T_AAAA:
 130               {
 131                 char ipv6[16]
 132                   = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0,
 133                      response_number >> 8, response_number,
 134                      i >> 8, i, 0, 0};
 135                 ipv6[15] = 2 * ctx->tcp + 4 * ctx->server_index;
 136                 resolv_response_add_data (b, &ipv6, sizeof (ipv6));
 137               }
 138               break;
 139             default:
 140               support_record_failure ();
 141               printf ("error: unexpected QTYPE: %s/%u/%u\n",
 142                       qname, qclass, qtype);
 143             }
 144           resolv_response_close_record (b);
 145         }
 146     }
 147 }
 148
 149 static char *
 150 expected_result (unsigned port, unsigned response_number)
 151 {
 152   struct xmemstream mem;
 153   xopen_memstream (&mem);
 154   /* We fail the second TCP query to the first server by closing the
 155      connection immediately, without returning any data.  This should
 156      cause failover to the second server.  */
 157   int server_index = 1;
 158   fprintf (mem.out, "address: STREAM/TCP 10.%u.%u.%u %u\n",
 159            (response_number >> 8) & 0xff, response_number & 0xff,
 160            2 + 4 * server_index, port);
 161   fprintf (mem.out, "address: STREAM/TCP 2001:db8::%x:%x %u\n",
 162            (response_number + 1) & 0xffff,
 163            2 + 4 * server_index, port);
 164   xfclose_memstream (&mem);
 165   return mem.buffer;
 166 }
 167
 168 static void
 169 test_different_sizes (void)
 170 {
 171   struct addrinfo hints =
 172     {
 173       .ai_family = AF_UNSPEC,
 174       .ai_socktype = SOCK_STREAM,
 175       .ai_protocol = IPPROTO_TCP,
 176     };
 177   struct addrinfo *ai;
 178   char *expected;
 179   int ret;
 180
 181   /* This magic number produces a response size close to 2048
 182      bytes.  */
 183   initial_address_count = 124;
 184   response_number = 0;
 185
 186   ret = getaddrinfo ("www.example", "80", &hints, &ai);
 187   expected = expected_result (80, 3);
 188   check_addrinfo ("www.example:80", ai, ret, expected);
 189   if (ret == 0)
 190     freeaddrinfo (ai);
 191   free (expected);
 192
 193   response_number = 0;
 194   ret = getaddrinfo ("www123.example", "80", &hints, &ai);
 195   if (ret == 0)
 196     freeaddrinfo (ai);
 197
 198   response_number = 0;
 199   ret = getaddrinfo ("www1234.example", "80", &hints, &ai);
 200   if (ret == 0)
 201     freeaddrinfo (ai);
 202
 203   response_number = 0;
 204   ret = getaddrinfo ("www12345.example", "80", &hints, &ai);
 205   if (ret == 0)
 206     freeaddrinfo (ai);
 207 }
 208
 209 static int
 210 do_test (void)
 211 {
 212   struct resolv_test *obj = resolv_test_start
 213     ((struct resolv_redirect_config)
 214      {
 215        .response_callback = response
 216      });
 217
 218   test_different_sizes ();
 219
 220   _res.options |= RES_SNGLKUP;
 221   test_different_sizes ();
 222
 223   _res.options |= RES_SNGLKUPREOP;
 224   test_different_sizes ();
 225
 226   resolv_test_end (obj);
 227   return 0;
 228 }
 229
 230 #include <support/test-driver.c>