Add getDnsNetId cmd in DnsProxyListener

This command is used to get the netId which resolver
will use for sending DNS query.

Correst ResponseCode.h from const to constexpr
for test.

Input:
    cmd format: getdnsnetid netId
               -netid: selected netid of the process

Output:
    Success: 1. ResponseCode::DnsProxyQueryResult
             2. dnsNetId

    Fail:    1. ResponseCode::DnsProxyQueryResult
             2. -errno

    Possible errno:
                   EINVAL
Bug: 129530368
Test: built, flashed, booted
          system/netd/tests/runtests.sh

Merged-In: Ie81751b762a780ed843bea255c1507ed03660c0e
(cherry picked from commit 4bd0e67a9568e72fe18ac4e0ab98c5bf5e6b75ee)

Change-Id: I18c4c04ab4547dc29cf97abc49ad01563e534e26
diff --git a/libnetdutils/include/netdutils/ResponseCode.h b/libnetdutils/include/netdutils/ResponseCode.h
index 5703ce8..c170684 100644
--- a/libnetdutils/include/netdutils/ResponseCode.h
+++ b/libnetdutils/include/netdutils/ResponseCode.h
@@ -23,65 +23,67 @@
 class ResponseCode {
     // Keep in sync with
     // frameworks/base/services/java/com/android/server/NetworkManagementService.java
-public:
+  public:
     // 100 series - Requestion action was initiated; expect another reply
     // before proceeding with a new command.
-    static const int ActionInitiated           = 100;
-    static const int InterfaceListResult       = 110;
-    static const int TetherInterfaceListResult = 111;
-    static const int TetherDnsFwdTgtListResult = 112;
-    static const int TtyListResult             = 113;
-    static const int TetheringStatsListResult  = 114;
-    static const int TetherDnsFwdNetIdResult   = 115;
+    // clang-format off
+    static constexpr int ActionInitiated                = 100;
+    static constexpr int InterfaceListResult            = 110;
+    static constexpr int TetherInterfaceListResult      = 111;
+    static constexpr int TetherDnsFwdTgtListResult      = 112;
+    static constexpr int TtyListResult                  = 113;
+    static constexpr int TetheringStatsListResult       = 114;
+    static constexpr int TetherDnsFwdNetIdResult        = 115;
 
     // 200 series - Requested action has been successfully completed
-    static const int CommandOkay               = 200;
-    static const int TetherStatusResult        = 210;
-    static const int IpFwdStatusResult         = 211;
-    static const int InterfaceGetCfgResult     = 213;
-    // Formerly: int SoftapStatusResult        = 214;
-    static const int UsbRNDISStatusResult      = 215;
-    static const int InterfaceRxCounterResult  = 216;
-    static const int InterfaceTxCounterResult  = 217;
-    static const int InterfaceRxThrottleResult = 218;
-    static const int InterfaceTxThrottleResult = 219;
-    static const int QuotaCounterResult        = 220;
-    static const int TetheringStatsResult      = 221;
+    static constexpr int CommandOkay                    = 200;
+    static constexpr int TetherStatusResult             = 210;
+    static constexpr int IpFwdStatusResult              = 211;
+    static constexpr int InterfaceGetCfgResult          = 213;
+    // Formerly: int SoftapStatusResult                 = 214;
+    static constexpr int UsbRNDISStatusResult           = 215;
+    static constexpr int InterfaceRxCounterResult       = 216;
+    static constexpr int InterfaceTxCounterResult       = 217;
+    static constexpr int InterfaceRxThrottleResult      = 218;
+    static constexpr int InterfaceTxThrottleResult      = 219;
+    static constexpr int QuotaCounterResult             = 220;
+    static constexpr int TetheringStatsResult           = 221;
     // NOTE: keep synced with bionic/libc/dns/net/gethnamaddr.c
-    static const int DnsProxyQueryResult       = 222;
-    static const int ClatdStatusResult         = 223;
+    static constexpr int DnsProxyQueryResult            = 222;
+    static constexpr int ClatdStatusResult              = 223;
 
     // 400 series - The command was accepted but the requested action
     // did not take place.
-    static const int OperationFailed           = 400;
-    static const int DnsProxyOperationFailed   = 401;
-    static const int ServiceStartFailed        = 402;
-    static const int ServiceStopFailed         = 403;
+    static constexpr int OperationFailed                = 400;
+    static constexpr int DnsProxyOperationFailed        = 401;
+    static constexpr int ServiceStartFailed             = 402;
+    static constexpr int ServiceStopFailed              = 403;
 
     // 500 series - The command was not accepted and the requested
     // action did not take place.
-    static const int CommandSyntaxError = 500;
-    static const int CommandParameterError = 501;
+    static constexpr int CommandSyntaxError             = 500;
+    static constexpr int CommandParameterError          = 501;
 
     // 600 series - Unsolicited broadcasts
-    static const int InterfaceChange                = 600;
-    static const int BandwidthControl               = 601;
-    static const int ServiceDiscoveryFailed         = 602;
-    static const int ServiceDiscoveryServiceAdded   = 603;
-    static const int ServiceDiscoveryServiceRemoved = 604;
-    static const int ServiceRegistrationFailed      = 605;
-    static const int ServiceRegistrationSucceeded   = 606;
-    static const int ServiceResolveFailed           = 607;
-    static const int ServiceResolveSuccess          = 608;
-    static const int ServiceSetHostnameFailed       = 609;
-    static const int ServiceSetHostnameSuccess      = 610;
-    static const int ServiceGetAddrInfoFailed       = 611;
-    static const int ServiceGetAddrInfoSuccess      = 612;
-    static const int InterfaceClassActivity         = 613;
-    static const int InterfaceAddressChange         = 614;
-    static const int InterfaceDnsInfo               = 615;
-    static const int RouteChange                    = 616;
-    static const int StrictCleartext                = 617;
+    static constexpr int InterfaceChange                = 600;
+    static constexpr int BandwidthControl               = 601;
+    static constexpr int ServiceDiscoveryFailed         = 602;
+    static constexpr int ServiceDiscoveryServiceAdded   = 603;
+    static constexpr int ServiceDiscoveryServiceRemoved = 604;
+    static constexpr int ServiceRegistrationFailed      = 605;
+    static constexpr int ServiceRegistrationSucceeded   = 606;
+    static constexpr int ServiceResolveFailed           = 607;
+    static constexpr int ServiceResolveSuccess          = 608;
+    static constexpr int ServiceSetHostnameFailed       = 609;
+    static constexpr int ServiceSetHostnameSuccess      = 610;
+    static constexpr int ServiceGetAddrInfoFailed       = 611;
+    static constexpr int ServiceGetAddrInfoSuccess      = 612;
+    static constexpr int InterfaceClassActivity         = 613;
+    static constexpr int InterfaceAddressChange         = 614;
+    static constexpr int InterfaceDnsInfo               = 615;
+    static constexpr int RouteChange                    = 616;
+    static constexpr int StrictCleartext                = 617;
+    // clang-format on
 };
 
 }  // namespace netdutils