blob: 67daeaf4e73ba72e48b65bbcf38b007f424f172a [file] [log] [blame]
#!/usr/bin/env python
"""
This example expands on the print_packets example. It checks for ICMP packets and displays the ICMP contents.
"""
import dpkt
import datetime
from dpkt.utils import mac_to_str, inet_to_str
def print_icmp(pcap):
"""Print out information about each packet in a pcap
Args:
pcap: dpkt pcap reader object (dpkt.pcap.Reader)
"""
# 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_to_str(eth.src), mac_to_str(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)))
def test():
"""Open up a test pcap file and print out the packets"""
with open('data/dns_icmp.pcap', 'rb') as f:
pcap = dpkt.pcap.Reader(f)
print_icmp(pcap)
if __name__ == '__main__':
test()