tree ee8e3b0303a7223053ef1151a419753c34700266
parent cf157b7512d880b5da8b54443cbbfc13474b795a
author Ningyuan Wang <nywang@google.com> 1458922925 -0700
committer Ningyuan Wang <nywang@google.com> 1459445137 -0700

dhcp client: support unicast for renewing and release

RFC 2131 requires the DHCP client to send unicast packet
to DHCP server upon renewing and release.
This create a new udp socket for sending unicast packet.
In this way kernel can fill the destination mac address
for us.
This also renames the old socket name to raw_socket.
This also fix the condition for sending dhcp release and
clearing sockets.

Bug: 25642025
TEST=compile, and test using python scripts

Change-Id: I2a984ebe8f4e3870426deaa149fe4c8abe79c9e7