/lib/rex/socket/range_walker.rb

# -*- coding: binary -*-
require 'rex/socket'

module Rex
module Socket

###
#
# This class provides an interface to enumerating an IP range
#
# This class uses start,stop pairs to represent ranges of addresses.  This
# is very efficient for large numbers of consecutive addresses, and not
# show-stoppingly inefficient when storing a bunch of non-consecutive
# addresses, which should be a somewhat unusual case.
#
###
class RangeWalker

	#
	# Initializes a walker instance using the supplied range
	#
	def initialize(parseme)
		if parseme.is_a? RangeWalker
			@ranges = parseme.ranges.dup
		else
			@ranges = parse(parseme)
		end
		reset
	end

	#
	# Calls the instance method
	#
	# This is basically only useful for determining if a range can be parsed
	#
	def self.parse(parseme)
		self.new.parse(parseme)
	end

	#
	# Turn a human-readable range string into ranges we can step through one address at a time.
	#
	# Allow the following formats:
	#	"a.b.c.d e.f.g.h"
	#	"a.b.c.d, e.f.g.h"
	# where each chunk is CIDR notation, (e.g. '10.1.1.0/24') or a range in nmap format (see expand_nmap)
	#
	# OR this format
	#	"a.b.c.d-e.f.g.h"
	# where a.b.c.d and e.f.g.h are single IPs and the second must be
	# bigger than the first.
	#
	def parse(parseme)
		return nil if not parseme
		ranges = []
		parseme.split(', ').map{ |a| a.split(' ') }.flatten.each { |arg|
			opts = {}

			# Handle IPv6 first (support ranges, but not CIDR)
			if arg.include?(":")
				addrs = arg.split('-', 2)

				# Handle a single address
				if addrs.length == 1
					addr, scope_id = addrs[0].split('%')
					opts[:scope_id] = scope_id if scope_id

					return false unless Rex::Socket.is_ipv6?(addr)
					addr = Rex::Socket.addr_atoi(addr)
					ranges.push [addr, addr, true, opts]
					next
				end

				addr1, scope_id = addrs[0].split('%')
				opts[:scope_id] = scope_id if scope_id

				addr2, scope_id = addrs[0].split('%')
				( opts[:scope_id] ||= scope_id ) if scope_id

				return false if not (Rex::Socket.is_ipv6?(addr1) and Rex::Socket.is_ipv6?(addr2))

				# Handle IPv6 ranges in the form of 2001::1-2001::10
				addr1 = Rex::Socket.addr_atoi(addr1)
				addr2 = Rex::Socket.addr_atoi(addr2)

				ranges.push [addr1, addr2, true, opts]
				next

			# Handle IPv4 CIDR
			elsif arg.include?("/")
				# Then it's CIDR notation and needs special case
				return false if arg =~ /[,-]/ # Improper CIDR notation (can't mix with 1,3 or 1-3 style IP ranges)
				return false if arg.scan("/").size > 1 # ..but there are too many slashes
				ip_part,mask_part = arg.split("/")
				return false if ip_part.nil? or ip_part.empty? or mask_part.nil? or mask_part.empty?
				return false if mask_part !~ /^[0-9]{1,2}$/ # Illegal mask -- numerals only
				return false if mask_part.to_i > 32 # This too -- between 0 and 32.
				begin
					Rex::Socket.addr_atoi(ip_part) # This allows for "www.metasploit.com/24" which is fun.
				rescue Resolv::ResolvError
					return false # Can't resolve the ip_part, so bail.
				end

				expanded = expand_cidr(arg)
				if expanded
					ranges.push(expanded)
				else
					return false
				end

			# Handle hostnames
			elsif arg =~ /[^-0-9,.*]/
				# Then it's a domain name and we should send it on to addr_atoi
				# unmolested to force a DNS lookup.
				Rex::Socket.addr_atoi_list(arg).each { |addr| ranges.push [addr, addr, false, opts] }

			# Handle IPv4 ranges
			elsif arg =~ /^([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})-([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3})$/
				# Then it's in the format of 1.2.3.4-5.6.7.8
				# Note, this will /not/ deal with DNS names, or the fancy/obscure 10...1-10...2
				begin
					addrs = [Rex::Socket.addr_atoi($1), Rex::Socket.addr_atoi($2)]
					return false if addrs[0] > addrs[1] # The end is greater than the beginning.
					ranges.push [addrs[0], addrs[1], false, opts]
				rescue Resolv::ResolvError # Something's broken, forget it.
					return false
				end
			else
				# Returns an array of ranges
				expanded = expand_nmap(arg)
				if expanded
					expanded.each { |r| ranges.push(r) }
				end
			end
		}

		# Remove any duplicate ranges
		ranges = ranges.uniq

		return ranges
	end

	#
	# Resets the subnet walker back to its original state.
	#
	def reset
		return false if not valid?
		@curr_range = 0
		@curr_addr = @ranges[0][0]
		@length = 0
		@ranges.each { |r| @length += r[1] - r[0] + 1 }
	end

	#
	# Returns the next IP address.
	#
	def next_ip
		return false if not valid?
		if (@curr_addr > @ranges[@curr_range][1])
			if (@curr_range >= @ranges.length - 1)
				return nil
			end
			@curr_range += 1
			@curr_addr = @ranges[@curr_range][0]
		end
		addr = Rex::Socket.addr_itoa(@curr_addr, @ranges[@curr_range][2])

		if @ranges[@curr_range][3][:scope_id]
			addr = addr + '%' + @ranges[@curr_range][3][:scope_id]
		end

		@curr_addr += 1
		return addr
	end

	def valid?
		(@ranges and not @ranges.empty?)
	end

	#
	# Returns true if the argument is an ip address that falls within any of
	# the stored ranges.
	#
	def include?(addr)
		return false if not @ranges
		if (addr.is_a? String)
			addr = Rex::Socket.addr_atoi(addr)
		end
		@ranges.map { |r|
			if r[0] <= addr and addr <= r[1]
				return true
			end
		}
		return false
	end

	#
	# Returns true if this RangeWalker includes all of the addresses in the
	# given RangeWalker
	#
	def include_range?(range_walker)
		return false if ((not @ranges) or @ranges.empty?)
		return false if not range_walker.ranges

		range_walker.ranges.all? do |start, stop|
			ranges.any? do |self_start, self_stop|
				r = (self_start..self_stop)
				r.include?(start) and r.include?(stop)
			end
		end
	end

	#
	# Calls the given block with each address. This is basically a wrapper for
	# #next_ip
	#
	def each(&block)
		while (ip = next_ip)
			block.call(ip)
		end
	end

	#
	# Returns an array with one element, a Range defined by the given CIDR
	# block.
	#
	def expand_cidr(arg)
		start,stop = Rex::Socket.cidr_crack(arg)
		if !start or !stop
			return false
		end
		range = Range.new
		range.start = Rex::Socket.addr_atoi(start)
		range.stop = Rex::Socket.addr_atoi(stop)
		range.ipv6 = (arg.include?(":"))
		range.options = {}

		return range
	end

	#
	# Expands an nmap-style host range x.x.x.x where x can be simply "*" which
	# means 0-255 or any combination and repitition of:
	#    i,n
	#    n-m
	#    i,n-m
	#    n-m,i
	# ensuring that n is never greater than m.
	#
	# non-unique elements will be removed
	#  e.g.:
	#    10.1.1.1-3,2-2,2 =>  ["10.1.1.1", "10.1.1.2", "10.1.1.3"]
	#    10.1.1.1-3,7 =>  ["10.1.1.1", "10.1.1.2", "10.1.1.3", "10.1.1.7"]
	#
	# Returns an array of Ranges
	#
	def expand_nmap(arg)
		# Can't really do anything with IPv6
		return false if arg.include?(":")

		# nmap calls these errors, but it's hard to catch them with our
		# splitting below, so short-cut them here
		return false if arg.include?(",-") or arg.include?("-,")

		bytes = []
		sections = arg.split('.')
		if sections.length != 4
			# Too many or not enough dots
			return false
		end
		sections.each { |section|
			if section.empty?
				# pretty sure this is an unintentional artifact of the C
				# functions that turn strings into ints, but it sort of makes
				# sense, so why not
				#   "10...1" => "10.0.0.1"
				section = "0"
			end

			if section == "*"
				# I think this ought to be 1-254, but this is how nmap does it.
				section = "0-255"
			elsif section.include?("*")
				return false
			end

			# Break down the sections into ranges like so
			# "1-3,5-7" => ["1-3", "5-7"]
			ranges = section.split(',', -1)
			sets = []
			ranges.each { |r|
				bounds = []
				if r.include?('-')
					# Then it's an actual range, break it down into start,stop
					# pairs:
					#   "1-3" => [ 1, 3 ]
					# if the lower bound is empty, start at 0
					# if the upper bound is empty, stop at 255
					#
					bounds = r.split('-', -1)
					return false if (bounds.length > 2)

					bounds[0] = 0   if bounds[0].nil? or bounds[0].empty?
					bounds[1] = 255 if bounds[1].nil? or bounds[1].empty?
					bounds.map!{|b| b.to_i}
					return false if bounds[0] > bounds[1]
				else
					# Then it's a single value
					bounds[0] = r.to_i
				end
				return false if bounds[0] > 255 or (bounds[1] and bounds[1] > 255)
				return false if bounds[1] and bounds[0] > bounds[1]
				if bounds[1]
					bounds[0].upto(bounds[1]) do |i|
						sets.push(i)
					end
				elsif bounds[0]
					sets.push(bounds[0])
				end
			}
			bytes.push(sets.sort.uniq)
		}

		#
		# Combinitorically squish all of the quads together into a big list of
		# ip addresses, stored as ints
		#
		# e.g.:
		#  [[1],[1],[1,2],[1,2]]
		#  =>
		#  [atoi("1.1.1.1"),atoi("1.1.1.2"),atoi("1.1.2.1"),atoi("1.1.2.2")]
		addrs = []
		for a in bytes[0]
			for b in bytes[1]
				for c in bytes[2]
					for d in bytes[3]
						ip = (a << 24) + (b << 16) + (c << 8) + d
						addrs.push ip
					end
				end
			end
		end

		addrs.sort!
		addrs.uniq!

		rng = Range.new
		rng.ipv6 = false
		rng.options = {}
		rng.start = addrs[0]

		ranges = []
		1.upto(addrs.length - 1) do |idx|
			if addrs[idx - 1] + 1 == addrs[idx]
				# Then this address is contained in the current range
				next
			else
				# Then this address is the upper bound for the current range
				rng.stop = addrs[idx - 1]
				ranges.push(rng.dup)
				rng.start = addrs[idx]
			end
		end
		rng.stop = addrs[addrs.length - 1]
		ranges.push(rng.dup)
		return ranges
	end

	#
	# The total number of IPs within the range
	#
	attr_reader :length

	# for backwards compatibility
	alias :num_ips :length

	attr_reader :ranges

end

class Range < Array # :nodoc: all
	def start; self[0]; end
	def stop;  self[1]; end
	def ipv6;  self[2]; end
	def options; self[3]; end
	def start=(val); self[0] = val; end
	def stop=(val);  self[1] = val; end
	def ipv6=(val);  self[2] = val; end
	def options=(val); self[3] = val; end
end

end
end