python pcap file analyse

pypcap.py

from pcapy import open_offline

def filter_HTTPGET(packet):
	if packet[0x33] == '\x06' and packet[0x52:0x56] == "GET ":#tcp and tcp[20:4] = 0x47455420
		return True
	return False

def get_source_IP(packet):
	#return '.'.join(str(ord(i)) for i in packet[0x36:0x3A])
	return tuple(ord(i) for i in packet[0x36:0x3A])

classA, classB, classC = 0, 0, 0
#source_IP_file = open("sip", 'w')
pc = open_offline("ttt.pcap")
data = pc.next()
while data[0]:
	if filter_HTTPGET(data[1]):
		#source_IP_file.write(get_source_IP(data[1])+'\n')
		sourceIP = get_source_IP(data[1])
		if sourceIP[0] < 128:
			classA += 1
		elif sourceIP[0] < 192:
			classB += 1
		elif sourceIP[0] < 224:
			classC += 1
	data = pc.next()
print classA, classB, classC
#source_IP_file.close()