Class: OVSImager::TcpDump

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

Constant Summary collapse

SIZE = 
400

Instance Method Summary collapse

Constructor Details

#initialize(ping = false, from = nil, to = nil) ⇒ TcpDump

Returns a new instance of TcpDump.



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# File 'lib/ovsimager/tcpdump.rb', line 6

def initialize(ping=false, from=nil, to=nil)
  throw 'must be root.' if Process::UID.eid != 0
  @ping = ping
  @from = from
  @to = to
end

Instance Method Details

#test(ifaces) ⇒ Object 



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# File 'lib/ovsimager/tcpdump.rb', line 13

def test(ifaces)
  result = {}
  ping = nil
  if @ping
    puts "Sending ping from #{@from||'default'} to #{@to} ..."
    ping = IO.popen("ping -s #{SIZE} -c 15 #{@from?'-I '+@from:''} #{@to} >/dev/null", "r")
  end

  threads = ifaces.map do |(nn, iref)|
    Thread.new do
      iface = iref[:name]
      Thread.current[:iface] = iface
      ns = iref[:ns]
      nscmd = ns == :root ? '' : "ip netns exec #{ns} "
      dump = IO.popen("exec #{nscmd}tcpdump -v -l -n -nn -i #{iface} \\( icmp or udp port 4789 or proto gre \\) and greater #{SIZE} 2>&1", "r")
      puts dump.gets
      time_end = Time.now + 5
      req_from = req_to = rep_from = rep_to = nil
      cap_from = cap_to = cap_type = cap_id = nil
      cap = false
      cap_line = 0
      while (waitmax = time_end - Time.now) > 0 do
        rs, ws, = IO.select([dump], [], [], waitmax)
        break unless rs
        if r = rs[0]
          msg = r.gets
          break unless msg
          # puts msg
          if msg.match(/([\da-f\.:]+)\.\d+ > ([\da-f\.:]+)\.\d+: (VXLAN).*vni (\d+)/) ||
              msg.match(/([\da-f\.:]+) > ([\da-f\.:]+): (GRE).*key=([\da-f]+)/)
            cap_from = $1
            cap_to = $2
            cap_type = $3
            cap_id = $4
            cap_line = 3
          elsif msg.match(/length #{SIZE+8}/) &&
              msg.match(/([\da-f\.:]+) > ([\da-f\.:]+): ICMP echo (request|reply)/)
            if $3 == 'request'
              req_from = $1
              req_to = $2
            else
              rep_from = $1
              rep_to = $2
            end
            if cap_line > 0
              if $3 == 'request'
                cap = [cap_from, cap_to, cap_type, cap_id]
              else
                cap = [cap_to, cap_from, cap_type, cap_id]
              end
            end
            break if req_from && req_to && rep_from && rep_to
          end
          cap_line -= 1 if cap_line > 0
        end
      end
      puts "Killing tcpdump(#{dump.pid}) on interface #{iface}."
      Process.kill('TERM', dump.pid)
      dump.close
      ifname_netns = iface + (ns == :root ? "" : ":" + ns.to_s)
      result[ifname_netns] = [req_from, req_to, rep_from, rep_to, {}]
      result[ifname_netns][4][:cap] = cap if cap
    end
  end
  threads.each {|th| th.join(10)}
  if @ping
    Process.kill('TERM', ping.pid)
    ping.close
  end
  return result
end