receive.py

#!/usr/bin/env python3
import os
import sys

from scapy.all import *
from scapy.layers.inet import _IPOption_HDR

class Probe(Packet):
    name = "probe"
    fields_desc=[BitField("byte_ct_2", 0, 32),
                 BitField("byte_ct_3", 0, 32),
                 BitField("switch_id", 0, 32)]

bind_layers(Ether, Probe, type = 0x0802)
bind_layers(Probe, IP, switch_id = 1)

def get_if():
    ifs=get_if_list()
    iface=None
    for i in get_if_list():
        if "eth0" in i:
            iface=i
            break;
    if not iface:
        print("Cannot find eth0 interface")
        exit(1)
    return iface

def handle_pkt(pkt, file):
    if Ether in pkt:
        #print("got a packet")
        if pkt[Ether].type == 2048: # IP packet
            file.write(str(pkt[IP].id)+'\n')
        elif pkt[Ether].type == 2050: # Query packet
            print("PROBE PACKET")
            pkt.show2()
            print("Bytes on upper path:", pkt[Probe].byte_ct_2);
            print("Bytes on lower path:", pkt[Probe].byte_ct_3);
    #    hexdump(pkt)
        sys.stdout.flush()


def main():
    ifaces = [i for i in os.listdir('/sys/class/net/') if 'eth' in i]
    iface = ifaces[0]
    print("sniffing on %s" % iface)
    sys.stdout.flush()
    output=open("m2t3.txt","w")
    sniff(iface = iface,
          prn = lambda x: handle_pkt(x, output))
    output.close()

if __name__ == '__main__':
    main()