def verify_ip_precedence_ip_precedence(packets, exclude_src_ip=None):
"""Verify that all packets have mapped IP precedence value to EXP
Args:
packets ('obj'): Packets to analyze
exclude_src_ip ('str'): Source ip to exclude
Returns:
True / False
Raises:
None
"""
try:
from scapy.all import load_contrib
from scapy.contrib.mpls import MPLS
except ImportError:
raise ImportError(
'scapy is not installed, please install it by running: '
'pip install scapy') from None
log.info(
"Verifying that all the packets have mapped IP precedence value to EXP"
)
if exclude_src_ip:
log.info(
"Exclude packets with source ip {ip}".format(ip=exclude_src_ip))
load_contrib("mpls")
not_matched = False
no_check = True
for pkt in packets:
if pkt.haslayer("Raw"):
mpls_pkt = MPLS(pkt["Raw"])
if mpls_pkt.haslayer("IP") and (
exclude_src_ip is None
or mpls_pkt["IP"].src != exclude_src_ip):
no_check = False
log.info("Analyzing the following packet:"
"\n-------------------------------\n{}".format(
mpls_pkt.show(dump=True)))
tos = "{0:08b}".format(mpls_pkt["IP"].tos)
cos = "{0:03b}".format(mpls_pkt["MPLS"].cos)
if tos[0:3] != cos:
not_matched = True
log.info(
"MPLS EXP 'COS' value didn't match the IP Precedence 'TOS'"
)
else:
log.info(
"MPLS EXP 'COS' value matched the IP Precedence 'TOS'")
if no_check:
log.info("Didn't find any 'IPv4' protocol packets to "
"analyze out of the {} packets".format(len(packets)))
if not_matched:
return False
return True
def get_ntp_packet(packets, ip_address_source, ip_address_destination):
""" Find ntp packet with src ip and dest ip in pcap file
Args:
packets (`obj`): pcap object
ip_address_source (`str`): source ip
ip_address_destination (`str`): destination ip
Returns:
pkt (`obj`): verified ntp packet
"""
try:
from scapy.contrib.mpls import MPLS
except ImportError:
raise ImportError(
'scapy is not installed, please install it by running: '
'pip install scapy') from None
for pkt in packets:
if pkt.haslayer("Raw"):
mpls_pkt = MPLS(pkt["Raw"])
if (mpls_pkt.haslayer("IP") and mpls_pkt.haslayer("NTPHeader")
and mpls_pkt["IP"].src == ip_address_source
and mpls_pkt["IP"].dst == ip_address_destination):
log.info("Found NTP packet:\n{pkt}".format(pkt=mpls_pkt.show(
dump=True)))
return pkt
elif (pkt.haslayer("IP") and pkt.haslayer("NTPHeader")
and pkt["IP"].src == ip_address_source
and pkt["IP"].dst == ip_address_destination):
log.info(
"Found NTP packet:\n{pkt}".format(pkt=pkt.show(dump=True)))
return pkt
return None