[5014_phase2] Add Dhcp4 and DhcpDdns toplevel configs to pass all tests

src/bin/dhcp6/dhcp6_lexer.ll

@@ -738,6 +738,23 @@ JSONString                              \"{JSONStringCharacter}*\"
     }
 }
 
+\"Dhcp4\" {
+    switch(driver.ctx_) {
+    case isc::dhcp::Parser6Context::CONFIG:
+        return isc::dhcp::Dhcp6Parser::make_DHCP4(loc);
+    default:
+        return isc::dhcp::Dhcp6Parser::make_STRING("Dhcp4", loc);
+    }
+}
+
+\"DhcpDdns\" {
+    switch(driver.ctx_) {
+    case isc::dhcp::Parser6Context::CONFIG:
+        return isc::dhcp::Dhcp6Parser::make_DHCPDDNS(loc);
+    default:
+        return isc::dhcp::Dhcp6Parser::make_STRING("DhcpDdns", loc);
+    }
+}
 
 {JSONString} {
     // A string has been matched. It contains the actual string and single quotes.

src/bin/dhcp6/dhcp6_parser.yy

@@ -124,6 +124,9 @@ using namespace std;
   ENABLE_UPDATES "enable-updates"
   QUALIFYING_SUFFIX "qualifying-suffix"
 
+  DHCP4 "Dhcp4"
+  DHCPDDNS "DhcpDdns"
+
  // Not real tokens, just a way to signal what the parser is expected to
  // parse.
   TOPLEVEL_GENERIC_JSON
@@ -256,6 +259,9 @@ global_objects: global_object
 // This represents a single top level entry, e.g. Dhcp6 or DhcpDdns.
 global_object: dhcp6_object
              | logging_object
+	     | dhcp4_object
+	     | dhcpddns_object
+	     | unknown_map_entry
              ;
 
 dhcp6_object: DHCP6 {
@@ -1181,6 +1187,20 @@ qualifying_suffix: QUALIFYING_SUFFIX {
     ctx.leave();
 };
 
+dhcp4_object: DHCP4 {
+    ctx.enter(ctx.NO_KEYWORD);
+} COLON value {
+    ctx.stack_.back()->set("Dhcp4", $4);
+    ctx.leave();
+};
+
+dhcpddns_object: DHCPDDNS {
+    ctx.enter(ctx.NO_KEYWORD);
+} COLON value {
+    ctx.stack_.back()->set("DhcpDdns", $4);
+    ctx.leave();
+};
+
 %%
 
 void

src/bin/dhcp6/parser_context.cc

@@ -115,7 +115,7 @@ Parser6Context::context_name()
     case NO_KEYWORD:
         return ("__no keyword__");
     case CONFIG:
-        return ("__config__");
+        return ("toplevel");
     case DHCP6:
         return ("Dhcp6");
     case LOGGING:

src/bin/dhcp6/tests/parser_unittest.cc

@@ -409,21 +409,27 @@ TEST(ParserTest, errors) {
               "expecting }");
     testError("{ 123 }\n",
               Parser6Context::PARSER_DHCP6,
-              "<string>:1.3-5: syntax error, unexpected integer, "
-              "expecting Dhcp6 or Logging");
+              "<string>:1.3-5: syntax error, unexpected integer");
     testError("{ \"foo\" }\n",
               Parser6Context::PARSER_GENERIC_JSON,
               "<string>:1.9: syntax error, unexpected }, "
               "expecting :");
     testError("{ \"foo\" }\n",
               Parser6Context::PARSER_DHCP6,
-              "<string>:1.3-7: syntax error, unexpected constant string, "
-              "expecting Dhcp6 or Logging");
+              "<string>:1.9: syntax error, unexpected }, expecting :");
+    testError("{ \"foo\":null }\n",
+              Parser6Context::PARSER_DHCP6,
+              "<string>:1.3-7: got unexpected keyword "
+              "\"foo\" in toplevel map.");
     testError("{ \"Dhcp6\" }\n",
               Parser6Context::PARSER_DHCP6,
               "<string>:1.11: syntax error, unexpected }, "
               "expecting :");
-    testError("{}{}",
+    testError("{ \"Dhcp4\":[]\n",
+              Parser6Context::PARSER_DHCP6,
+              "<string>:2.1: syntax error, unexpected end of file, "
+              "expecting \",\" or }");
+    testError("{}{}\n",
               Parser6Context::PARSER_GENERIC_JSON,
               "<string>:1.3: syntax error, unexpected {, "
               "expecting end of file");