Print ICMP Example

This example expands on the print_packets example. It checks for ICMP packets and displays the ICMP contents.

Code Excerpt

# For each packet in the pcap process the contents
for timestamp, buf in pcap:

    # Unpack the Ethernet frame (mac src/dst, ethertype)
    eth = dpkt.ethernet.Ethernet(buf)

    # Make sure the Ethernet data contains an IP packet
    if not isinstance(eth.data, dpkt.ip.IP):
        print('Non IP Packet type not supported %s\n' % eth.data.__class__.__name__)
        continue

    # Now grab the data within the Ethernet frame (the IP packet)
    ip = eth.data

    # Now check if this is an ICMP packet
    if isinstance(ip.data, dpkt.icmp.ICMP):
        icmp = ip.data

        # Pull out fragment information (flags and offset all packed into off field, so use bitmasks)
        do_not_fragment = bool(ip.off & dpkt.ip.IP_DF)
        more_fragments = bool(ip.off & dpkt.ip.IP_MF)
        fragment_offset = ip.off & dpkt.ip.IP_OFFMASK

        # Print out the info
        print('Timestamp: ', str(datetime.datetime.utcfromtimestamp(timestamp)))
        print('Ethernet Frame: ', mac_addr(eth.src), mac_addr(eth.dst), eth.type)
        print('IP: %s -> %s   (len=%d ttl=%d DF=%d MF=%d offset=%d)' % \
              (inet_to_str(ip.src), inet_to_str(ip.dst), ip.len, ip.ttl, do_not_fragment, more_fragments, fragment_offset))
        print('ICMP: type:%d code:%d checksum:%d data: %s\n' % (icmp.type, icmp.code, icmp.sum, repr(icmp.data)))

Example Output

Timestamp:  2013-05-30 22:45:17.283187
Ethernet Frame:  60:33:4b:13:c5:58 02:1a:11:f0:c8:3b 2048
IP: 192.168.43.9 -> 8.8.8.8   (len=84 ttl=64 DF=0 MF=0 offset=0)
ICMP: type:8 code:0 checksum:48051 data: Echo(id=55099, data='Q\xa7\xd6}\x00\x04Q\xe4\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./01234567')

Timestamp:  2013-05-30 22:45:17.775391
Ethernet Frame:  02:1a:11:f0:c8:3b 60:33:4b:13:c5:58 2048
IP: 8.8.8.8 -> 192.168.43.9   (len=84 ttl=40 DF=0 MF=0 offset=0)
ICMP: type:0 code:0 checksum:50099 data: Echo(id=55099, data='Q\xa7\xd6}\x00\x04Q\xe4\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./01234567')

...

Set full code at: https://github.com/kbandla/dpkt/blob/master/examples/print_icmp.py