Revert "[ST02.2] Use the getters of DnsHeader"

Revert submission 1387135-st02

Reason for revert: Usage of TYPE_CNAME in a library shared among
modules does not interact well with current module release process

Reverted Changes:
Ib5616c65c:[ST02.2] Use the getters of DnsHeader
I5e58f99b0:[ST02.1] Add TYPE_CNAME constant to DnsResolver
I0c1547cbc:[ST02] Add methods for synthesizing DNS packets

Change-Id: Ia35cb3e21cd90e036a07018e2d9c1ee662ce86a2

Tethering/tests/integration/src/android/net/EthernetTetheringTest.java

@@ -1512,7 +1512,7 @@ public class EthernetTetheringTest {
         final TestDnsPacket dnsQuery = TestDnsPacket.getTestDnsPacket(buf);
         assertNotNull(dnsQuery);
         Log.d(TAG, "Forwarded UDP source port: " + udpHeader.srcPort + ", DNS query id: "
-                + dnsQuery.getHeader().getId());
+                + dnsQuery.getHeader().id);
 
         // [2] Send DNS reply.
         // DNS server --> upstream --> dnsmasq forwarding --> downstream --> tethered device
@@ -1522,7 +1522,7 @@ public class EthernetTetheringTest {
         final Inet4Address remoteIp = (Inet4Address) TEST_IP4_DNS;
         final Inet4Address tetheringUpstreamIp = (Inet4Address) TEST_IP4_ADDR.getAddress();
         sendDownloadPacketDnsV4(remoteIp, tetheringUpstreamIp, DNS_PORT,
-                (short) udpHeader.srcPort, (short) dnsQuery.getHeader().getId(), tester);
+                (short) udpHeader.srcPort, (short) dnsQuery.getHeader().id, tester);
     }
 
     private <T> List<T> toList(T... array) {

framework/src/android/net/DnsResolver.java

@@ -544,7 +544,7 @@ public final class DnsResolver {
 
         DnsAddressAnswer(@NonNull byte[] data) throws ParseException {
             super(data);
-            if ((mHeader.getFlags() & (1 << 15)) == 0) {
+            if ((mHeader.flags & (1 << 15)) == 0) {
                 throw new ParseException("Not an answer packet");
             }
             if (mHeader.getRecordCount(QDSECTION) == 0) {

tests/cts/net/src/android/net/cts/DnsResolverTest.java

@@ -200,13 +200,13 @@ public class DnsResolverTest {
             super(data);
 
             // Check QR field.(query (0), or a response (1)).
-            if ((mHeader.getFlags() & (1 << 15)) == 0) {
+            if ((mHeader.flags & (1 << 15)) == 0) {
                 throw new DnsParseException("Not an answer packet");
             }
         }
 
         int getRcode() {
-            return mHeader.getFlags() & 0x0F;
+            return mHeader.rcode;
         }
 
         int getANCount() {