extension functions on IPOption settings in scapy

readme.md

• Remarks

The realization of these IP options is based on RFC 791. But support for these IP options from ISP is by no means guaranteed. Especially, lssr and ssrr options are the most interesting ones but are generally forbidden by ISP's routers. I don't write the implementation on security options since I think it is of no use (correct me if I am wrong). For details on IP headers and settings, see my blog (in Chinese).

• Usage example:

IP(dst='some.ip1', options=IPOption(lsrr('some.ip2','some.ip3')))/ICMP()
IP(dst=some.ip, ttl=64,IPOption(record_route(9))/ICMP() 
IP(dst=some.ip, src=fake.ip, IPOption(timestamp(3,2,'stamp.ip.1','stamp.ip.2'))/ICMP()

ipoption.py

from scapy.all import sr1, IP, IPOption,ICMP
import ipaddress as ipa

def record_route(hop=1):
	if hop >= 10:
		raise Exception('exceed the max length of ip header')
	length = chr(hop*4+3)
	option_head = b'\x07'+length.encode()+b'\x04'
	route_data = "".join(['\x00']*4*hop)
	option = option_head+('%s'%route_data).encode()
	return option

def lsrr(*source_route_table):
	hop = len(source_route_table)
	if hop >= 10:
		raise Exception('exceed the max length of ip header')
	length = chr(hop*4+3)
	option_head = b'\x83'+length.encode()+b'\x04'
	option = option_head
	for ip in source_route_table:
		ip = ipa.v4_int_to_packed(int(ipa.IPv4Address(ip)))
		option = option + ip
	return option

def ssrr(*source_route_table):
	hop = len(source_route_table)
	if hop >= 10:
		raise Exception('exceed the max length of ip header')
	length = chr(hop*4+3)
	option_head = b'\x89'+length.encode()+b'\x04'
	option = option_head
	for ip in source_route_table:
		ip = ipa.v4_int_to_packed(int(ipa.IPv4Address(ip)))
		option = option + ip
	return option

def timestamp(flag=0,hop=1,*specified_route):
	if flag == 0:
		if hop >= 10:
			raise Exception('exceed the max length of ip header')
		length = chr (hop*4+4)
		option_head = b'\x44'+length.encode()+b'\x05\x00'
		route_data = "".join(['\x00']*4*hop)
		option = option_head+('%s'%route_data).encode()
		return option
	if flag == 1:
		if hop >= 5:
			raise Exception('exceed the max length of ip header')
		length = chr (hop*8+4)
		option_head = b'\x44'+length.encode()+b'\x05\x01'
		route_data = "".join(['\x00']*8*hop)
		option = option_head+('%s'%route_data).encode()
		return option
	if flag==3:
		hop_check = len(specified_route)
		if hop_check != hop:
			raise Exception('the number of routes is not consistent with hops')
		if hop >= 5:
			raise Exception('exceed the max length of ip header')
		length = chr (hop*8+4)
		option_head = b'\x44'+length.encode()+b'\x05\x03'
		option = option_head
		for ip in specified_route:
			ip = ipa.v4_int_to_packed(int(ipa.IPv4Address(ip)))
			option = option + ip + b'\x00\x00\x00\x00'		
		return option
	raise Exception('no such flag, flag must be set as 0,1,3 in timastamp option')

def streamid(byte_id):
	return b'\x88\x04'+byte_id