Add config reader for Primary DNS Suffix and corresponding unittest.

TBR=szym@chromium.org
BUG=114825
TEST=unittest and manual test


Review URL: http://codereview.chromium.org/10283004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@134984 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 76 insertions, 14 deletions

diff --git a/net/dns/dns_config_service_win.cc b/net/dns/dns_config_service_win.cc
index 5e7a530..327ea2a 100644
--- a/net/dns/dns_config_service_win.cc
+++ b/net/dns/dns_config_service_win.cc
@@ -46,6 +46,8 @@ const wchar_t* const kDnscachePath =
     L"SYSTEM\\CurrentControlSet\\Services\\Dnscache\\Parameters";
 const wchar_t* const kPolicyPath =
     L"SOFTWARE\\Policies\\Microsoft\\Windows NT\\DNSClient";
+const wchar_t* const kPrimaryDnsSuffixPath =
+    L"SOFTWARE\\Policies\\Microsoft\\System\\DNSClient";
 
 // Convenience for reading values using RegKey.
 class RegistryReader : public base::NonThreadSafe {
@@ -299,15 +301,27 @@ bool ConvertSettingsToDnsConfig(const DnsSystemSettings& settings,
     }
   }
 
-  if (!settings.tcpip_domain.set)
-    return true;
-
+  // In absence of explicit search list, suffix search is:
+  // [primary suffix, connection-specific suffix, devolution of primary suffix].
+  // Primary suffix can be set by policy (primary_dns_suffix) or
+  // user setting (tcpip_domain).
+  //
+  // The policy (primary_dns_suffix) can be edited via Group Policy Editor
+  // (gpedit.msc) at Local Computer Policy => Computer Configuration
+  // => Administrative Template => Network => DNS Client => Primary DNS Suffix.
+  //
+  // The user setting (tcpip_domain) can be configurred at Computer Name in
+  // System Settings
   std::string primary_suffix;
-  if (!ParseDomainASCII(settings.tcpip_domain.value, &primary_suffix))
-    return true;  // No primary suffix, hence no devolution.
-
-  // Primary suffix goes in front.
-  config->search.insert(config->search.begin(), primary_suffix);
+  if ((settings.primary_dns_suffix.set &&
+       ParseDomainASCII(settings.primary_dns_suffix.value, &primary_suffix)) ||
+      (settings.tcpip_domain.set &&
+       ParseDomainASCII(settings.tcpip_domain.value, &primary_suffix))) {
+    // Primary suffix goes in front.
+    config->search.insert(config->search.begin(), primary_suffix);
+  } else {
+    return true; // No primary suffix, hence no devolution.
+  }
 
   // Devolution is determined by precedence: policy > dnscache > tcpip.
   // |enabled|: UseDomainNameDevolution and |level|: DomainNameDevolutionLevel
@@ -439,6 +453,7 @@ class DnsConfigServiceWin::ConfigReader : public SerialWorker {
     RegistryReader tcpip6_reader(kTcpip6Path);
     RegistryReader dnscache_reader(kDnscachePath);
     RegistryReader policy_reader(kPolicyPath);
+    RegistryReader primary_dns_suffix_reader(kPrimaryDnsSuffixPath);
 
     if (!policy_reader.ReadString(L"SearchList",
                                   &settings.policy_search_list))
@@ -464,6 +479,10 @@ class DnsConfigServiceWin::ConfigReader : public SerialWorker {
                                  &settings.append_to_multi_label_name))
       return;
 
+    if (!primary_dns_suffix_reader.ReadString(L"PrimaryDnsSuffix",
+                                              &settings.primary_dns_suffix))
+      return;
+
     success_ = ConvertSettingsToDnsConfig(settings, &dns_config_);
   }
 
diff --git a/net/dns/dns_config_service_win.h b/net/dns/dns_config_service_win.h
index 0d75d9f..703eb7a 100644
--- a/net/dns/dns_config_service_win.h
+++ b/net/dns/dns_config_service_win.h
@@ -88,6 +88,8 @@ struct NET_EXPORT_PRIVATE DnsSystemSettings {
   RegString tcpip_search_list;
   // SYSTEM\CurrentControlSet\Tcpip\Parameters\Domain
   RegString tcpip_domain;
+  // SOFTWARE\Policies\Microsoft\System\DNSClient\PrimaryDnsSuffix
+  RegString primary_dns_suffix;
 
   // SOFTWARE\Policies\Microsoft\Windows NT\DNSClient
   DevolutionSetting policy_devolution;
diff --git a/net/dns/dns_config_service_win_unittest.cc b/net/dns/dns_config_service_win_unittest.cc
index fa5da54..796c942 100644
--- a/net/dns/dns_config_service_win_unittest.cc
+++ b/net/dns/dns_config_service_win_unittest.cc
@@ -213,6 +213,7 @@ TEST(DnsConfigServiceWinTest, ConvertSuffixSearch) {
         { true, L"policy.searchlist.a,policy.searchlist.b" },
         { true, L"tcpip.searchlist.a,tcpip.searchlist.b" },
         { true, L"tcpip.domain" },
+        { true, L"primary.dns.suffix" },
       },
       { "policy.searchlist.a", "policy.searchlist.b" },
     },
@@ -222,15 +223,47 @@ TEST(DnsConfigServiceWinTest, ConvertSuffixSearch) {
         { false },
         { true, L"tcpip.searchlist.a,tcpip.searchlist.b" },
         { true, L"tcpip.domain" },
+        { true, L"primary.dns.suffix" },
       },
       { "tcpip.searchlist.a", "tcpip.searchlist.b" },
     },
-    {  // Void SearchList.
+    {  // Void SearchList. Using tcpip.domain
       {
         CreateAdapterAddresses(infos),
         { true, L",bad.searchlist,parsed.as.empty" },
         { true, L"tcpip.searchlist,good.but.overridden" },
         { true, L"tcpip.domain" },
+        { false },
+      },
+      { "tcpip.domain", "connection.suffix" },
+    },
+    {  // Void SearchList. Using primary.dns.suffix
+      {
+        CreateAdapterAddresses(infos),
+        { true, L",bad.searchlist,parsed.as.empty" },
+        { true, L"tcpip.searchlist,good.but.overridden" },
+        { true, L"tcpip.domain" },
+        { true, L"primary.dns.suffix" },
+      },
+      { "primary.dns.suffix", "connection.suffix" },
+    },
+    {  // Void SearchList. Using tcpip.domain when primary.dns.suffix is empty
+      {
+        CreateAdapterAddresses(infos),
+        { true, L",bad.searchlist,parsed.as.empty" },
+        { true, L"tcpip.searchlist,good.but.overridden" },
+        { true, L"tcpip.domain" },
+        { true, L"" },
+      },
+      { "tcpip.domain", "connection.suffix" },
+    },
+    {  // Void SearchList. Using tcpip.domain when primary.dns.suffix is NULL
+      {
+        CreateAdapterAddresses(infos),
+        { true, L",bad.searchlist,parsed.as.empty" },
+        { true, L"tcpip.searchlist,good.but.overridden" },
+        { true, L"tcpip.domain" },
+        { true },
       },
       { "tcpip.domain", "connection.suffix" },
     },
@@ -240,6 +273,7 @@ TEST(DnsConfigServiceWinTest, ConvertSuffixSearch) {
         { false },
         { false },
         { true },
+        { true },
         { { true, 1 }, { true, 2 } },
       },
       { "connection.suffix" },
@@ -250,9 +284,10 @@ TEST(DnsConfigServiceWinTest, ConvertSuffixSearch) {
         { false },
         { false },
         { true, L"a.b.c.d.e" },
-        { { true, 1 }, { false } },
-        { { true, 0 }, { true, 3 } },
-        { { true, 0 }, { true, 1 } },
+        { false },
+        { { true, 1 }, { false } },   // policy_devolution: enabled, level
+        { { true, 0 }, { true, 3 } }, // dnscache_devolution
+        { { true, 0 }, { true, 1 } }, // tcpip_devolution
       },
       { "a.b.c.d.e", "connection.suffix", "b.c.d.e", "c.d.e" },
     },
@@ -262,11 +297,12 @@ TEST(DnsConfigServiceWinTest, ConvertSuffixSearch) {
         { false },
         { false },
         { true, L"a.b.c.d.e" },
+        { true, L"f.g.i.l.j" },
         { { false }, { true, 4 } },
         { { true, 1 }, { false } },
         { { true, 0 }, { true, 3 } },
       },
-      { "a.b.c.d.e", "connection.suffix", "b.c.d.e" },
+      { "f.g.i.l.j", "connection.suffix", "g.i.l.j" },
     },
     {  // Devolution enabled by default.
       {
@@ -274,6 +310,7 @@ TEST(DnsConfigServiceWinTest, ConvertSuffixSearch) {
         { false },
         { false },
         { true, L"a.b.c.d.e" },
+        { false },
         { { false }, { false } },
         { { false }, { true, 3 } },
         { { false }, { true, 1 } },
@@ -286,6 +323,7 @@ TEST(DnsConfigServiceWinTest, ConvertSuffixSearch) {
         { false },
         { false },
         { true, L"a.b" },
+        { false },
         { { false }, { false } },
         { { false }, { true, 2 } },
         { { false }, { true, 2 } },
@@ -299,6 +337,7 @@ TEST(DnsConfigServiceWinTest, ConvertSuffixSearch) {
         { false },
         { false },
         { true, L"a.b.c.d.e" },
+        { false },
         { { true, 1 }, { false } },
         { { true, 1 }, { false } },
         { { true, 1 }, { false } },
@@ -311,6 +350,7 @@ TEST(DnsConfigServiceWinTest, ConvertSuffixSearch) {
         { false },
         { false },
         { true, L"a.b.c.d.e" },
+        { false },
         { { false }, { true, 1 } },
         { { true, 1 }, { true, 3 } },
         { { true, 1 }, { true, 4 } },
@@ -323,6 +363,7 @@ TEST(DnsConfigServiceWinTest, ConvertSuffixSearch) {
         { false },
         { false },
         { true, L"a.b.c.d.e" },
+        { false },
         { { false }, { true, 3 } },
         { { false }, { true, 3 } },
         { { true, 0 }, { true, 3 } },
@@ -366,7 +407,7 @@ TEST(DnsConfigServiceWinTest, AppendToMultiLabelName) {
     const TestCase& t = cases[i];
     internal::DnsSystemSettings settings = {
       CreateAdapterAddresses(infos),
-      { false }, { false }, { false },
+      { false }, { false }, { false }, { false },
       { { false }, { false } },
       { { false }, { false } },
       { { false }, { false } },