dhcp client: add class DHCPV4

Add class DHCPV4 for dhcp_client.
This is the class that executes the DHCP ipv4 state machine logic.

Bug: 25642025
TEST=compile

Change-Id: Ia173d3f79bf12b12feb1c7dd60d58385e085e31e
diff --git a/dhcp.h b/dhcp.h
new file mode 100644
index 0000000..ac006c5
--- /dev/null
+++ b/dhcp.h
@@ -0,0 +1,48 @@
+//
+// Copyright (C) 2015 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef DHCP_CLIENT_DHCP_H_
+#define DHCP_CLIENT_DHCP_H_
+
+#include <base/macros.h>
+
+namespace dhcp_client {
+
+class DHCP {
+ public:
+  // DHCP service type.
+  enum ServiceType {
+    SERVICE_TYPE_IPV4 = 0,
+    SERVICE_TYPE_IPV6 = 1,
+    SERVICE_TYPE_BOTH = 2
+  };
+
+  // DHCP states.
+  enum class State {
+    INIT,
+    SELECT,
+    REQUEST,
+    BOUND,
+    RENEW,
+    REBIND,
+    REBOOT,
+    RELEASE
+  };
+};
+
+}  // namespace dhcp_client
+
+#endif  // DHCP_CLIENT_DHCP_H_