class SecurityExtension(scapy.Packet):
name = "SCION Security Extension"
fields_desc = [
scapy.BitEnumField('next_hdr', None, 8, scapy.IP_PROTOS),
scapy.ByteField('hdr_len', None),
scapy.XByteField('extType', 0x2),
scapy.ByteEnumField("secMode", 0x0, {
0x0: "AES-CMAC",
0x1: "HMAC_SHA256",
0x2: "Ed25519",
0x3: "GCM_AES128"
}),
scapy.XBitField('metadata', 0xffffffff, 4 * 8),
scapy.MultipleTypeField([
(scapy.XBitField('authenticator', None,
16 * 8), lambda pkt: pkt.secMode == 0x0),
(scapy.XBitField('authenticator', None,
32 * 8), lambda pkt: pkt.secMode == 0x1),
(scapy.XBitField('authenticator', None,
64 * 8), lambda pkt: pkt.secMode == 0x2),
(scapy.XBitField('authenticator', None,
16 * 8), lambda pkt: pkt.secMode == 0x3),
], scapy.StrField("authenticator", None)),
]
def extract_padding(self, p):
# TODO fix when removing hard-coded v4
return "", p
def post_build(self, pkt, pay):
if self.hdr_len == None:
self.hdr_len = len(pkt)
pkt = pkt[:1] + struct.pack('B', int(self.hdr_len / 8)) + pkt[2:]
return pkt + pay
class HopField(scapy.Packet):
IMMUTABLE_FLAGS = 0x0 # TODO
FLAGS = 0
RANGE_SKIP_FLAGS = 1
RANGE_END = 8
RANGE_BEFORE_MAC = 5
name = 'SCION Hop field'
fields_desc = [
scapy.XBitField('flags', 0x0, 8),
scapy.ByteField('expiry', 63),
scapy.BitField('ingress_if', None, 12),
scapy.BitField('egress_if', None, 12),
scapy.XBitField('mac', None, 3 * 8), # TODO
]
def extract_padding(self, p):
return "", p
assert sys.version_info >= (
3,
), "Due to incompatibilities around handling bytes, this only works under Python 3"
from scapy.all import Ether, IP, UDP
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import cmac
from cryptography.hazmat.primitives.ciphers import algorithms
HF_MAC_KEY = b'\0' * 15 + b'\x47' # 128w0x47
SCION_ADDR_TYPE = {1: 'ipv4', 2: 'ipv6', 3: 'svc'}
ISDField = scapy.ShortField
ASField = lambda name, default: scapy.XBitField(name, default, 6 * 8)
def raw(packet):
return str(packet) # would be bytes in python3
class UnixTimeField(scapy.IntField):
def i2repr(self, pkt, x):
if x is None: return None
return time.strftime('%d %b %Y %H:%M:%S UTC', time.gmtime(x))
class ISD_AS(scapy.Packet):
name = 'ISD-AS'
fields_desc = [