Ruby libpcap fails when passing command-line argument

Ruby
1

Hi,

Can someone please help me out here? I’m trying to use Ruby/Libpcap
extension to write a rudimentary packet sniffer.

I downloaded ruby/libpcap 0.6 from
http://www.goto.info.waseda.ac.jp/~fukusima/ruby/pcap-e.html.

The following code breaks when calling it from the command-line with a
parameter, such as:

$>ruby dumptraffic.rb en1
/usr/local/lib/ruby/site_ruby/1.8/universal-darwin8.0/pcap.bundle:
warning: do not use Fixnums as Symbols
/usr/local/lib/ruby/site_ruby/1.8/universal-darwin8.0/pcap.bundle:
warning: do not use Fixnums as Symbols
/usr/local/lib/ruby/site_ruby/1.8/universal-darwin8.0/pcap.bundle:
warning: do not use Fixnums as Symbols
setfilter: parse error
$>

The code:

------- start of code

require ‘pcaplet’

include Pcap

class Sniffer
def sniff(d)
pcaplet = Pcaplet.new("-i " + d)
c = pcaplet.capture
d = Dumper.open(c,“dump.txt”)

c.each_packet(50) { |pkt|
    if pkt.ip?
        d.dump(pkt)
        puts "hello from #{pkt.src.to_num_s}"
    end
}

pcaplet.close

end
end

if FILE == $0
d = ARGV[0]
sniffit = Sniffer.new
sniffit.sniff(d)
end

---- end of code

Any help would be greatly appreciated. Thanks.

  • kenny r.