Class: Pcap::Pcaplet

Inherits:
Object
  • Object
show all
Defined in:
lib/pcaplet.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(args = nil) ⇒ Pcaplet

Returns a new instance of Pcaplet.



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# File 'lib/pcaplet.rb', line 23

def initialize(args = nil)
  if args
	ARGV[0,0] = args.split(/\s+/)
  end
  usage(1) unless getopts("dnv", "i:", "r:", "c:-1", "s:68")
  $DEBUG   |= $OPT_d
  $VERBOSE |= $OPT_v

  @device = $OPT_i
  @rfile = $OPT_r
  Pcap.convert = !$OPT_n
  @count   = $OPT_c.to_i
  @snaplen = $OPT_s.to_i
  @filter = ARGV.join(' ')

  # check option consistency
  usage(1) if @device && @rfile
  if !@device and !@rfile
    @device = Pcap.lookupdev
  end

  # open
  begin
	if @device
	  @capture = Capture.open_live(@device, @snaplen)
	elsif @rfile
	  if @rfile !~ /\.gz$/
 @capture = Capture.open_offline(@rfile)
	  else
 $stdin = IO.popen("gzip -dc < #@rfile", 'r')
 @capture = Capture.open_offline('-')
	  end
	end
	@capture.setfilter(@filter)
  rescue PcapError, ArgumentError
	$stdout.flush
	$stderr.puts $!
	exit(1)
  end
end

Instance Attribute Details

#capture ⇒ Object (readonly)

Returns the value of attribute capture.



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# File 'lib/pcaplet.rb', line 64

def capture
  @capture
end

Instance Method Details

#add_filter(f) ⇒ Object 



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# File 'lib/pcaplet.rb', line 66

def add_filter(f)
  if @filter == nil || @filter =~ /^\s*$/  # if empty
	@filter = f
  else
	f = f.source if f.is_a? Filter
	@filter = "( #{@filter} ) and ( #{f} )"
  end
  @capture.setfilter(@filter)
end

#close ⇒ Object 



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# File 'lib/pcaplet.rb', line 107

def close
  @capture.close
end

#each_packet(&block) ⇒ Object Also known as: each 



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# File 'lib/pcaplet.rb', line 76

def each_packet(&block)
  begin
	duplicated = (RUBY_PLATFORM =~ /linux/ && @device == "lo")
    unless duplicated
      @capture.loop(@count, &block)
    else
      flip = true
      @capture.loop(@count) do |pkt|
        flip = (! flip)
        next if flip
        block.call pkt
      end
    end
  rescue Interrupt
    $stdout.flush
    $stderr.puts("Interrupted.")
    $stderr.puts $@.join("\n\t") if $DEBUG
  ensure
	# print statistics if live
	if @device
	  stat = @capture.stats
	  if stat
 $stderr.print("#{stat.recv} packets received by filter\n");
 $stderr.print("#{stat.drop} packets dropped by kernel\n");
	  end
	end
  end
end

#usage(status, msg = nil) ⇒ Object 



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# File 'lib/pcaplet.rb', line 17

def usage(status, msg = nil)
  $stderr.puts msg if msg
  pcaplet_usage
  exit(status)
end