[net/dns] Instrument DnsConfigService to measure performance and failures.

net/dns/dns_config_service_posix_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <resolv.h>
 
 #include "base/sys_byteorder.h"
 #include "net/dns/dns_config_service_posix.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 12 matching lines @@
 const char* kNameserversIPv6[] = {
     NULL,
     "2001:DB8:0::42",
     NULL,
     "::FFFF:129.144.52.38",
 };
 
 // Fills in |res| with sane configuration.
 void InitializeResState(res_state res) {
   memset(res, 0, sizeof(*res));
-  res->options = RES_INIT | RES_ROTATE;
+  res->options = RES_INIT | RES_DEFAULT | RES_ROTATE;

[mmenke, 2012/06/18 17:19:50]

Should RES_DEFAULT be manually expanded?  I assume the purpose of RES_DEFAULT is
for people compiling themselves to modify RES_DEFAULT, and we presumably don't
want the unit tests to fail on such systems.

   res->ndots = 2;
   res->retrans = 4;
   res->retry = 7;
 
   const char kDnsrch[] = "chromium.org" "\0" "example.com";
   memcpy(res->defdname, kDnsrch, sizeof(kDnsrch));
   res->dnsrch[0] = res->defdname;
   res->dnsrch[1] = res->defdname + sizeof("chromium.org");
 
   for (unsigned i = 0; i < arraysize(kNameserversIPv4) && i < MAXNS; ++i) {
@@ skipping 73 matching lines @@
   EXPECT_TRUE(config.IsValid());
 
   DnsConfig expected_config;
   EXPECT_FALSE(expected_config.EqualsIgnoreHosts(config));
   InitializeExpectedConfig(&expected_config);
   EXPECT_TRUE(expected_config.EqualsIgnoreHosts(config));
 }
 
 TEST(DnsConfigServicePosixTest, RejectEmptyNameserver) {
   struct __res_state res = {};
-  res.options = RES_INIT;
+  res.options = RES_INIT | RES_DEFAULT;

[mmenke, 2012/06/18 17:19:50]

Same comment as above.

   const char kDnsrch[] = "chromium.org";
   memcpy(res.defdname, kDnsrch, sizeof(kDnsrch));
   res.dnsrch[0] = res.defdname;
 
   struct sockaddr_in sa = {};
   sa.sin_family = AF_INET;
   sa.sin_port = base::HostToNet16(NS_DEFAULTPORT);
   sa.sin_addr.s_addr = INADDR_ANY;
   res.nsaddr_list[0] = sa;
   sa.sin_addr.s_addr = 0xCAFE1337;
   res.nsaddr_list[1] = sa;
   res.nscount = 2;
 
   DnsConfig config;
   EXPECT_FALSE(internal::ConvertResStateToDnsConfig(res, &config));
 
   sa.sin_addr.s_addr = 0xDEADBEEF;
   res.nsaddr_list[0] = sa;
   EXPECT_TRUE(internal::ConvertResStateToDnsConfig(res, &config));
 }
 
 }  // namespace
 }  // namespace net