dhcp.py

from ryu.lib import addrconv
from ryu.lib.packet import packet
from ryu.lib.packet import ethernet
from ryu.lib.packet import ipv4
from ryu.lib.packet import udp
from ryu.lib.packet import dhcp


class Config():
    controller_macAddr = '7e:49:b3:f0:f9:99' # don't modify, a dummy mac address for fill the mac enrty
    dns = '8.8.8.8' # don't modify, just for the dns entry
    start_ip = '192.168.1.2' # can be modified
    end_ip = '192.168.1.100' # can be modified
    netmask = '255.255.255.0' # can be modified

    # You may use above attributes to configure your DHCP server.
    # You can also add more attributes like "lease_time" to support bouns function.


class DHCPServer():
    hardware_addr = Config.controller_macAddr
    start_ip = Config.start_ip
    end_ip = Config.end_ip
    netmask = Config.netmask
    dns = Config.dns

    @classmethod
    def assemble_ack(cls, pkt, datapath, port):
        # TODO: Generate DHCP ACK packet here
        return ack_pkt

    @classmethod
    def assemble_offer(cls, pkt, datapath):
        # TODO: Generate DHCP OFFER packet here


    @classmethod
    def handle_dhcp(cls, datapath, port, pkt):
        # TODO: Specify the type of received DHCP packet
        # You may choose a valid IP from IP pool and genereate DHCP OFFER packet
        # Or generate a DHCP ACK packet
        # Finally send the generated packet to the host by using _send_packet method

    @classmethod
    def _send_packet(cls, datapath, port, pkt):
        ofproto = datapath.ofproto
        parser = datapath.ofproto_parser
        if isinstance(pkt, str):
            pkt = pkt.encode()
        pkt.serialize()
        data = pkt.data
        actions = [parser.OFPActionOutput(port=port)]
        out = parser.OFPPacketOut(datapath=datapath,
                                  buffer_id=ofproto.OFP_NO_BUFFER,
                                  in_port=ofproto.OFPP_CONTROLLER,
                                  actions=actions,
                                  data=data)
        datapath.send_msg(out)