commit f282cdbe7f436c75864e5640a409a10485e9abb2

Author: Florian Weimer <fweimer@redhat.com>

Date:   Fri Jun 24 18:16:41 2022 +0200

    resolv: Implement no-aaaa stub resolver option

    Reviewed-by: Carlos O'Donell <carlos@redhat.com>

diff --git a/resolv/Makefile b/resolv/Makefile

index 59e599535c7aa6eb..e8269dcb5bcf216b 100644

--- a/resolv/Makefile

+++ b/resolv/Makefile

@@ -51,6 +51,7 @@ routines := \

   nss_dns_functions \

   res-close \

   res-name-checking \

+  res-noaaaa \

   res-state \

   res_context_hostalias \

   res_enable_icmp \

@@ -93,6 +94,7 @@ tests += \

   tst-resolv-binary \

   tst-resolv-edns \

   tst-resolv-network \

+  tst-resolv-noaaaa \

   tst-resolv-nondecimal \

   tst-resolv-res_init-multi \

   tst-resolv-search \

@@ -256,6 +258,7 @@ $(objpfx)tst-resolv-res_init-multi: $(objpfx)libresolv.so \

   $(shared-thread-library)

 $(objpfx)tst-resolv-res_init-thread: $(objpfx)libresolv.so \

   $(shared-thread-library)

+$(objpfx)tst-resolv-noaaaa: $(objpfx)libresolv.so $(shared-thread-library)

 $(objpfx)tst-resolv-nondecimal: $(objpfx)libresolv.so $(shared-thread-library)

 $(objpfx)tst-resolv-qtypes: $(objpfx)libresolv.so $(shared-thread-library)

 $(objpfx)tst-resolv-rotate: $(objpfx)libresolv.so $(shared-thread-library)

diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c

index 7248ade18db5ba47..6e83fca1c5b1f98c 100644

--- a/resolv/nss_dns/dns-host.c

+++ b/resolv/nss_dns/dns-host.c

@@ -125,6 +125,14 @@ static enum nss_status gaih_getanswer (const querybuf *answer1, int anslen1,

 				       char *buffer, size_t buflen,

 				       int *errnop, int *h_errnop,

 				       int32_t *ttlp);

+static enum nss_status gaih_getanswer_noaaaa (const querybuf *answer1,

+					      int anslen1,

+					      const char *qname,

+					      struct gaih_addrtuple **pat,

+					      char *buffer, size_t buflen,

+					      int *errnop, int *h_errnop,

+					      int32_t *ttlp);

+

 static enum nss_status gethostbyname3_context (struct resolv_context *ctx,

 					       const char *name, int af,

@@ -370,17 +378,31 @@ _nss_dns_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat,

   int resplen2 = 0;

   int ans2p_malloced = 0;

+

   int olderr = errno;

-  int n = __res_context_search (ctx, name, C_IN, T_QUERY_A_AND_AAAA,

+  int n;

+

+  if ((ctx->resp->options & RES_NOAAAA) == 0)

+    {

+      n = __res_context_search (ctx, name, C_IN, T_QUERY_A_AND_AAAA,

 				host_buffer.buf->buf, 2048, &host_buffer.ptr,

 				&ans2p, &nans2p, &resplen2, &ans2p_malloced);

-  if (n >= 0)

-    {

-      status = gaih_getanswer (host_buffer.buf, n, (const querybuf *) ans2p,

-			       resplen2, name, pat, buffer, buflen,

-			       errnop, herrnop, ttlp);

+      if (n >= 0)

+	status = gaih_getanswer (host_buffer.buf, n, (const querybuf *) ans2p,

+				 resplen2, name, pat, buffer, buflen,

+				 errnop, herrnop, ttlp);

     }

   else

+    {

+      n = __res_context_search (ctx, name, C_IN, T_A,

+				host_buffer.buf->buf, 2048, NULL,

+				NULL, NULL, NULL, NULL);

+      if (n >= 0)

+	status = gaih_getanswer_noaaaa (host_buffer.buf, n,

+					name, pat, buffer, buflen,

+					errnop, herrnop, ttlp);

+    }

+  if (n < 0)

     {

       switch (errno)

 	{

@@ -1388,3 +1410,21 @@ gaih_getanswer (const querybuf *answer1, int anslen1, const querybuf *answer2,

   return status;

 }

+

+/* Variant of gaih_getanswer without a second (AAAA) response.  */

+static enum nss_status

+gaih_getanswer_noaaaa (const querybuf *answer1, int anslen1, const char *qname,

+		       struct gaih_addrtuple **pat,

+		       char *buffer, size_t buflen,

+		       int *errnop, int *h_errnop, int32_t *ttlp)

+{

+  int first = 1;

+

+  enum nss_status status = NSS_STATUS_NOTFOUND;

+  if (anslen1 > 0)

+    status = gaih_getanswer_slice (answer1, anslen1, qname,

+				   &pat, &buffer, &buflen,

+				   errnop, h_errnop, ttlp,

+				   &first);

+  return status;

+}

diff --git a/resolv/res-noaaaa.c b/resolv/res-noaaaa.c

new file mode 100644

index 0000000000000000..4ba197664a86aed7

--- /dev/null

+++ b/resolv/res-noaaaa.c

@@ -0,0 +1,143 @@

+/* Implement suppression of AAAA queries.

+   Copyright (C) 2022 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

+   <https://www.gnu.org/licenses/>.  */

+

+#include <resolv.h>

+#include <string.h>

+#include <resolv-internal.h>

+#include <resolv_context.h>

+#include <arpa/nameser.h>

+

+/* Returns true if the question type at P matches EXPECTED, and the

+   class is IN.  */

+static bool

+qtype_matches (const unsigned char *p, int expected)

+{

+  /* This assumes that T_A/C_IN constants are less than 256, which

+     they are.  */

+  return p[0] == 0 && p[1] == expected && p[2] == 0 && p[3] == C_IN;

+}

+

+/* Handle RES_NOAAAA translation of AAAA queries.  To produce a Name

+   Error (NXDOMAIN) repsonse for domain names that do not exist, it is

+   still necessary to send a query.  Using question type A is a

+   conservative choice.  In the returned answer, it is necessary to

+   switch back the question type to AAAA.  */

+bool

+__res_handle_no_aaaa (struct resolv_context *ctx,

+                      const unsigned char *buf, int buflen,

+                      unsigned char *ans, int anssiz, int *result)

+{

+  /* AAAA mode is not active, or the query looks invalid (will not be

+     able to be parsed).  */

+  if ((ctx->resp->options & RES_NOAAAA) == 0

+      || buflen <= sizeof (HEADER))

+    return false;

+

+  /* The replacement A query is produced here.  */

+  struct

+  {

+    HEADER header;

+    unsigned char question[NS_MAXCDNAME + 4];

+  } replacement;

+  memcpy (&replacement.header, buf, sizeof (replacement.header));

+

+  if (replacement.header.qr

+      || replacement.header.opcode != 0

+      || replacement.header.rcode != 0

+      || ntohs (replacement.header.qdcount) != 1

+      || ntohs (replacement.header.ancount) != 0

+      || ntohs (replacement.header.nscount) != 0)

+    /* Not a well-formed question.  Let the core resolver code produce

+       the proper error.  */

+    return false;

+

+  /* Disable EDNS0.  */

+  replacement.header.arcount = htons (0);

+

+  /* Extract the QNAME.  */

+  int ret = __ns_name_unpack (buf, buf + buflen, buf + sizeof (HEADER),

+                              replacement.question, NS_MAXCDNAME);

+  if (ret < 0)

+    /* Format error.  */

+    return false;

+

+  /* Compute the end of the question name.  */

+  const unsigned char *after_question = buf + sizeof (HEADER) + ret;

+

+  /* Check that we are dealing with an AAAA query.  */

+  if (buf + buflen - after_question < 4

+      || !qtype_matches (after_question, T_AAAA))

+    return false;

+

+  /* Find the place to store the type/class data in the replacement

+     query.  */

+  after_question = replacement.question;

+  /* This cannot fail because __ns_name_unpack above produced a valid

+     domain name.  */

+  (void) __ns_name_skip (&after_question, &replacement.question[NS_MAXCDNAME]);

+  unsigned char *start_of_query = (unsigned char *) &replacement;

+  const unsigned char *end_of_query = after_question + 4;

+

+  /* Produce an A/IN query.  */

+  {

+    unsigned char *p = (unsigned char *) after_question;

+    p[0] = 0;

+    p[1] = T_A;

+    p[2] = 0;

+    p[3] = C_IN;

+  }

+

+  /* Clear the output buffer, to avoid reading undefined data when

+     rewriting the result from A to AAAA.  */

+  memset (ans, 0, anssiz);

+

+  /* Always perform the message translation, independent of the error

+     code.  */

+  ret = __res_context_send (ctx,

+                            start_of_query, end_of_query - start_of_query,

+                            NULL, 0, ans, anssiz,

+                            NULL, NULL, NULL, NULL, NULL);

+

+  /* Patch in the AAAA question type if there is room and the A query

+     type was received.  */

+  after_question = ans + sizeof (HEADER);

+  if (__ns_name_skip (&after_question, ans + anssiz) == 0

+      && ans + anssiz - after_question >= 4

+      && qtype_matches (after_question, T_A))

+    {

+      ((unsigned char *) after_question)[1] = T_AAAA;

+

+      /* Create an aligned copy of the header.  Hide all data except

+         the question from the response.  Put back the header.  There is

+         no need to change the response code.  The zero answer count turns

+         a positive response with data into a no-data response.  */

+      memcpy (&replacement.header, ans, sizeof (replacement.header));

+      replacement.header.ancount = htons (0);

+      replacement.header.nscount = htons (0);

+      replacement.header.arcount = htons (0);

+      memcpy (ans, &replacement.header, sizeof (replacement.header));

+

+      /* Truncate the reply.  */

+      if (ret <= 0)

+        *result = ret;

+      else

+        *result = after_question - ans + 4;

+    }

+

+  return true;

+}

diff --git a/resolv/res_debug.c b/resolv/res_debug.c

index 030df0aa90c9f34f..b0fe69b1aa5186a0 100644

--- a/resolv/res_debug.c

+++ b/resolv/res_debug.c

@@ -613,6 +613,7 @@ p_option(u_long option) {

 	case RES_NOTLDQUERY:	return "no-tld-query";

 	case RES_NORELOAD:	return "no-reload";

 	case RES_TRUSTAD:	return "trust-ad";

+	case RES_NOAAAA:	return "no-aaaa";

 				/* XXX nonreentrant */

 	default:		sprintf(nbuf, "?0x%lx?", (u_long)option);

 				return (nbuf);

diff --git a/resolv/res_init.c b/resolv/res_init.c

index 6b2936eda9618ac9..8bde915903565f60 100644

--- a/resolv/res_init.c

+++ b/resolv/res_init.c

@@ -695,6 +695,7 @@ res_setoptions (struct resolv_conf_parser *parser, const char *options)

             { STRnLEN ("no-reload"), 0, RES_NORELOAD },

             { STRnLEN ("use-vc"), 0, RES_USEVC },

             { STRnLEN ("trust-ad"), 0, RES_TRUSTAD },

+            { STRnLEN ("no-aaaa"), 0, RES_NOAAAA },

           };

 #define noptions (sizeof (options) / sizeof (options[0]))

           for (int i = 0; i < noptions; ++i)

diff --git a/resolv/res_query.c b/resolv/res_query.c

index 75b0e5f2f7b51eb2..2f3c28cfc8c0d832 100644

--- a/resolv/res_query.c

+++ b/resolv/res_query.c

@@ -204,10 +204,26 @@ __res_context_query (struct resolv_context *ctx, const char *name,

 			free (buf);

 		return (n);

 	}

-	assert (answerp == NULL || (void *) *answerp == (void *) answer);

-	n = __res_context_send (ctx, query1, nquery1, query2, nquery2, answer,

-				anslen, answerp, answerp2, nanswerp2, resplen2,

-				answerp2_malloced);

+

+	/* Suppress AAAA lookups if required.  __res_handle_no_aaaa

+	   checks RES_NOAAAA first, so avoids parsing the

+	   just-generated query packet in most cases.  nss_dns avoids

+	   using T_QUERY_A_AND_AAAA in RES_NOAAAA mode, so there is no

+	   need to handle it here.  */

+	if (type == T_AAAA && __res_handle_no_aaaa (ctx, query1, nquery1,

+						    answer, anslen, &n))

+	  /* There must be no second query for AAAA queries.  The code

+	     below is still needed to translate NODATA responses.  */

+	  assert (query2 == NULL);

+	else

+	  {

+	    assert (answerp == NULL || (void *) *answerp == (void *) answer);

+	    n = __res_context_send (ctx, query1, nquery1, query2, nquery2,

+				    answer, anslen,

+				    answerp, answerp2, nanswerp2, resplen2,

+				    answerp2_malloced);

+	  }

+

 	if (use_malloc)

 		free (buf);

 	if (n < 0) {

diff --git a/resolv/res_send.c b/resolv/res_send.c

index 9f86f5fe47194887..8ac6a307b40fa2ca 100644

--- a/resolv/res_send.c

+++ b/resolv/res_send.c

@@ -438,8 +438,13 @@ context_send_common (struct resolv_context *ctx,

       RES_SET_H_ERRNO (&_res, NETDB_INTERNAL);

       return -1;

     }

-  int result = __res_context_send (ctx, buf, buflen, NULL, 0, ans, anssiz,

-				   NULL, NULL, NULL, NULL, NULL);

+

+  int result;

+  if (__res_handle_no_aaaa (ctx, buf, buflen, ans, anssiz, &result))

+    return result;

+

+  result = __res_context_send (ctx, buf, buflen, NULL, 0, ans, anssiz,

+			       NULL, NULL, NULL, NULL, NULL);

   __resolv_context_put (ctx);

   return result;

 }

diff --git a/resolv/resolv-internal.h b/resolv/resolv-internal.h

index 216e47ed42076b72..8ab02fc9e648d30f 100644

--- a/resolv/resolv-internal.h

+++ b/resolv/resolv-internal.h

@@ -78,6 +78,14 @@ int __res_context_send (struct resolv_context *, const unsigned char *, int,

                         int *, int *, int *);

 libc_hidden_proto (__res_context_send)

+/* Return true if the query has been handled in RES_NOAAAA mode.  For

+   that, RES_NOAAAA must be active, and the question type must be AAAA.

+   The caller is expected to return *RESULT as the return value.  */

+bool __res_handle_no_aaaa (struct resolv_context *ctx,

+                           const unsigned char *buf, int buflen,

+                           unsigned char *ans, int anssiz, int *result)

+  attribute_hidden;

+

 /* Internal function similar to res_hostalias.  */

 const char *__res_context_hostalias (struct resolv_context *,

                                      const char *, char *, size_t);

diff --git a/resolv/resolv.h b/resolv/resolv.h

index e7c8d44645912ddf..3a79ffea57a6916f 100644

--- a/resolv/resolv.h

+++ b/resolv/resolv.h

@@ -132,6 +132,7 @@ struct res_sym {

 					   as a TLD.  */

 #define RES_NORELOAD    0x02000000 /* No automatic configuration reload.  */

 #define RES_TRUSTAD     0x04000000 /* Request AD bit, keep it in responses.  */

+#define RES_NOAAAA      0x08000000 /* Suppress AAAA queries.  */

 #define RES_DEFAULT	(RES_RECURSE|RES_DEFNAMES|RES_DNSRCH)

diff --git a/resolv/tst-resolv-noaaaa.c b/resolv/tst-resolv-noaaaa.c

new file mode 100644

index 0000000000000000..56b25f88a58ad286

--- /dev/null

+++ b/resolv/tst-resolv-noaaaa.c

@@ -0,0 +1,533 @@

+/* Test the RES_NOAAAA resolver option.

+   Copyright (C) 2022 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

+   <https://www.gnu.org/licenses/>.  */

+

+#include <errno.h>

+#include <netdb.h>

+#include <resolv.h>

+#include <stdlib.h>

+#include <support/check.h>

+#include <support/check_nss.h>

+#include <support/resolv_test.h>

+#include <support/support.h>

+

+/* Used to keep track of the number of queries.  */

+static volatile unsigned int queries;

+

+static void

+response (const struct resolv_response_context *ctx,

+          struct resolv_response_builder *b,

+          const char *qname, uint16_t qclass, uint16_t qtype)

+{

+  /* Each test should only send one query.  */

+  ++queries;

+  TEST_COMPARE (queries, 1);

+

+  /* AAAA queries are supposed to be disabled.  */

+  TEST_VERIFY (qtype != T_AAAA);

+  TEST_COMPARE (qclass, C_IN);

+

+  /* The only other query type besides A is PTR.  */

+  if (qtype != T_A)

+    TEST_COMPARE (qtype, T_PTR);

+

+  int an, ns, ar;

+  char *tail;

+  if (sscanf (qname, "an%d.ns%d.ar%d.%ms", &an, &ns, &ar, &tail) != 4)

+    FAIL_EXIT1 ("invalid QNAME: %s\n", qname);

+  TEST_COMPARE_STRING (tail, "example");

+  free (tail);

+

+  if (an < 0 || ns < 0 || ar < 0)

+    {

+      struct resolv_response_flags flags = { .rcode = NXDOMAIN, };

+      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);

+  for (int i = 0; i < an; ++i)

+    {

+      resolv_response_open_record (b, qname, qclass, qtype, 60);

+      switch (qtype)

+        {

+        case T_A:

+          char ipv4[4] = {192, 0, 2, i + 1};

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

+          break;

+

+        case T_PTR:

+          char *name = xasprintf ("ptr-%d", i);

+          resolv_response_add_name (b, name);

+          free (name);

+          break;

+        }

+      resolv_response_close_record (b);

+    }

+

+  resolv_response_section (b, ns_s_ns);

+  for (int i = 0; i < ns; ++i)

+    {

+      resolv_response_open_record (b, qname, qclass, T_NS, 60);

+      char *name = xasprintf ("ns%d.example.net", i);

+      resolv_response_add_name (b, name);

+      free (name);

+      resolv_response_close_record (b);

+    }

+

+  resolv_response_section (b, ns_s_ar);

+  int addr = 1;

+  for (int i = 0; i < ns; ++i)

+    {

+      char *name = xasprintf ("ns%d.example.net", i);

+      for (int j = 0; j < ar; ++j)

+        {

+          resolv_response_open_record (b, name, qclass, T_A, 60);

+          char ipv4[4] = {192, 0, 2, addr};

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

+          resolv_response_close_record (b);

+

+          resolv_response_open_record (b, name, qclass, T_AAAA, 60);

+          char ipv6[16]

+            = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, addr};

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

+          resolv_response_close_record (b);

+

+          ++addr;

+        }

+      free (name);

+    }

+}

+

+/* Number of modes.  Lowest bit encodes *n* function vs implicit _res

+   argument.  The mode numbers themselves are arbitrary.  */

+enum { mode_count = 8 };

+

+/* res_send-like modes do not perform error translation.  */

+enum { first_send_mode = 6 };

+

+static int

+libresolv_query (unsigned int mode, const char *qname, uint16_t qtype,

+                 unsigned char *buf, size_t buflen)

+{

+  int saved_errno = errno;

+

+  TEST_VERIFY_EXIT (mode < mode_count);

+

+  switch (mode)

+    {

+    case 0:

+      return res_query (qname, C_IN, qtype, buf, buflen);

+    case 1:

+      return res_nquery (&_res, qname, C_IN, qtype, buf, buflen);

+    case 2:

+      return res_search (qname, C_IN, qtype, buf, buflen);

+    case 3:

+      return res_nsearch (&_res, qname, C_IN, qtype, buf, buflen);

+    case 4:

+      return res_querydomain (qname, "", C_IN, qtype, buf, buflen);

+    case 5:

+      return res_nquerydomain (&_res, qname, "", C_IN, qtype, buf, buflen);

+    case 6:

+      {

+        unsigned char querybuf[512];

+        int ret = res_mkquery (QUERY, qname, C_IN, qtype,

+                               NULL, 0, NULL, querybuf, sizeof (querybuf));

+        TEST_VERIFY_EXIT (ret > 0);

+        errno = saved_errno;

+        return res_send (querybuf, ret, buf, buflen);

+      }

+    case 7:

+      {

+        unsigned char querybuf[512];

+        int ret = res_nmkquery (&_res, QUERY, qname, C_IN, qtype,

+                                NULL, 0, NULL, querybuf, sizeof (querybuf));

+        TEST_VERIFY_EXIT (ret > 0);

+        errno = saved_errno;

+        return res_nsend (&_res, querybuf, ret, buf, buflen);

+      }

+    }

+  __builtin_unreachable ();

+}

+

+static int

+do_test (void)

+{

+  struct resolv_test *obj = resolv_test_start

+    ((struct resolv_redirect_config)

+     {

+       .response_callback = response

+     });

+

+  _res.options |= RES_NOAAAA;

+

+  check_hostent ("an1.ns2.ar1.example",

+                 gethostbyname ("an1.ns2.ar1.example"),

+                 "name: an1.ns2.ar1.example\n"

+                 "address: 192.0.2.1\n");

+  queries = 0;

+  check_hostent ("an0.ns2.ar1.example",

+                 gethostbyname ("an0.ns2.ar1.example"),

+                 "error: NO_ADDRESS\n");

+  queries = 0;

+  check_hostent ("an-1.ns2.ar1.example",

+                 gethostbyname ("an-1.ns2.ar1.example"),

+                 "error: HOST_NOT_FOUND\n");

+  queries = 0;

+

+  check_hostent ("an1.ns2.ar1.example AF_INET",

+                 gethostbyname2 ("an1.ns2.ar1.example", AF_INET),

+                 "name: an1.ns2.ar1.example\n"

+                 "address: 192.0.2.1\n");

+  queries = 0;

+  check_hostent ("an0.ns2.ar1.example AF_INET",

+                 gethostbyname2 ("an0.ns2.ar1.example", AF_INET),

+                 "error: NO_ADDRESS\n");

+  queries = 0;

+  check_hostent ("an-1.ns2.ar1.example AF_INET",

+                 gethostbyname2 ("an-1.ns2.ar1.example", AF_INET),

+                 "error: HOST_NOT_FOUND\n");

+  queries = 0;

+

+  check_hostent ("an1.ns2.ar1.example AF_INET6",

+                 gethostbyname2 ("an1.ns2.ar1.example", AF_INET6),

+                 "error: NO_ADDRESS\n");

+  queries = 0;

+  check_hostent ("an0.ns2.ar1.example AF_INET6",

+                 gethostbyname2 ("an0.ns2.ar1.example", AF_INET6),

+                 "error: NO_ADDRESS\n");

+  queries = 0;

+  check_hostent ("an-1.ns2.ar1.example AF_INET6",

+                 gethostbyname2 ("an-1.ns2.ar1.example", AF_INET6),

+                 "error: HOST_NOT_FOUND\n");

+  queries = 0;

+

+  /* Multiple addresses.  */

+  check_hostent ("an2.ns0.ar0.example",

+                 gethostbyname ("an2.ns0.ar0.example"),

+                 "name: an2.ns0.ar0.example\n"

+                 "address: 192.0.2.1\n"

+                 "address: 192.0.2.2\n");

+  queries = 0;

+  check_hostent ("an2.ns0.ar0.example AF_INET6",

+                 gethostbyname2 ("an2.ns0.ar0.example", AF_INET6),

+                 "error: NO_ADDRESS\n");

+  queries = 0;

+

+  /* getaddrinfo checks with one address.  */

+  struct addrinfo *ai;

+  int ret;

+  ret = getaddrinfo ("an1.ns2.ar1.example", "80",

+                     &(struct addrinfo)

+                     {

+                       .ai_family = AF_INET,

+                       .ai_socktype = SOCK_STREAM,

+                     }, &ai;;

+  check_addrinfo ("an1.ns2.ar1.example (AF_INET)", ai, ret,

+                  "address: STREAM/TCP 192.0.2.1 80\n");

+  freeaddrinfo (ai);

+  queries = 0;

+  ret = getaddrinfo ("an1.ns2.ar1.example", "80",

+                     &(struct addrinfo)

+                     {

+                       .ai_family = AF_INET6,

+                       .ai_socktype = SOCK_STREAM,

+                     }, &ai;;

+  check_addrinfo ("an1.ns2.ar1.example (AF_INET6)", ai, ret,

+                  "error: No address associated with hostname\n");

+  queries = 0;

+  ret = getaddrinfo ("an1.ns2.ar1.example", "80",

+                     &(struct addrinfo)

+                     {

+                       .ai_family = AF_UNSPEC,

+                       .ai_socktype = SOCK_STREAM,

+                     }, &ai;;

+  check_addrinfo ("an1.ns2.ar1.example (AF_UNSPEC)", ai, ret,

+                  "address: STREAM/TCP 192.0.2.1 80\n");

+  freeaddrinfo (ai);

+  queries = 0;

+

+  /* getaddrinfo checks with three addresses.  */

+  ret = getaddrinfo ("an3.ns2.ar1.example", "80",

+                     &(struct addrinfo)

+                     {

+                       .ai_family = AF_INET,

+                       .ai_socktype = SOCK_STREAM,

+                     }, &ai;;

+  check_addrinfo ("an3.ns2.ar1.example (AF_INET)", ai, ret,

+                  "address: STREAM/TCP 192.0.2.1 80\n"

+                  "address: STREAM/TCP 192.0.2.2 80\n"

+                  "address: STREAM/TCP 192.0.2.3 80\n");

+  freeaddrinfo (ai);

+  queries = 0;

+  ret = getaddrinfo ("an3.ns2.ar1.example", "80",

+                     &(struct addrinfo)

+                     {

+                       .ai_family = AF_INET6,

+                       .ai_socktype = SOCK_STREAM,

+                     }, &ai;;

+  check_addrinfo ("an3.ns2.ar1.example (AF_INET6)", ai, ret,

+                  "error: No address associated with hostname\n");

+  queries = 0;

+  ret = getaddrinfo ("an3.ns2.ar1.example", "80",

+                     &(struct addrinfo)

+                     {

+                       .ai_family = AF_UNSPEC,

+                       .ai_socktype = SOCK_STREAM,

+                     }, &ai;;

+  check_addrinfo ("an3.ns2.ar1.example (AF_UNSPEC)", ai, ret,

+                  "address: STREAM/TCP 192.0.2.1 80\n"

+                  "address: STREAM/TCP 192.0.2.2 80\n"

+                  "address: STREAM/TCP 192.0.2.3 80\n");

+  freeaddrinfo (ai);

+  queries = 0;

+

+  /* getaddrinfo checks with no address.  */

+  ret = getaddrinfo ("an0.ns2.ar1.example", "80",

+                     &(struct addrinfo)

+                     {

+                       .ai_family = AF_INET,

+                       .ai_socktype = SOCK_STREAM,

+                     }, &ai;;

+  check_addrinfo ("an0.ns2.ar1.example (AF_INET)", ai, ret,

+                  "error: No address associated with hostname\n");

+  queries = 0;

+  ret = getaddrinfo ("an0.ns2.ar1.example", "80",

+                     &(struct addrinfo)

+                     {

+                       .ai_family = AF_INET6,

+                       .ai_socktype = SOCK_STREAM,

+                     }, &ai;;

+  check_addrinfo ("an0.ns2.ar1.example (AF_INET6)", ai, ret,

+                  "error: No address associated with hostname\n");

+  queries = 0;

+  ret = getaddrinfo ("an0.ns2.ar1.example", "80",

+                     &(struct addrinfo)

+                     {

+                       .ai_family = AF_UNSPEC,

+                       .ai_socktype = SOCK_STREAM,

+                     }, &ai;;

+  check_addrinfo ("an-1.ns2.ar1.example (AF_UNSPEC)", ai, ret,

+                  "error: No address associated with hostname\n");

+  queries = 0;

+

+  /* getaddrinfo checks with NXDOMAIN.  */

+  ret = getaddrinfo ("an-1.ns2.ar1.example", "80",

+                     &(struct addrinfo)

+                     {

+                       .ai_family = AF_INET,

+                       .ai_socktype = SOCK_STREAM,

+                     }, &ai;;