## This file is part of Scapy
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## See http://www.secdev.org/projects/scapy for more informations
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## Copyright (C) Philippe Biondi <phil@secdev.org>
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## Copyright (C) 6WIND <olivier.matz@6wind.com>
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## This program is published under a GPLv2 license
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"""
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VRRP (Virtual Router Redundancy Protocol).
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"""
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from scapy.packet import *
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from scapy.fields import *
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from scapy.compat import *
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from scapy.layers.inet import *
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from scapy.layers.inet6 import *
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from scapy.error import warning
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IPPROTO_VRRP=112
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# RFC 3768 - Virtual Router Redundancy Protocol (VRRP)
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class VRRP(Packet):
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fields_desc = [
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BitField("version", 2, 4),
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BitField("type", 1, 4),
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ByteField("vrid", 1),
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ByteField("priority", 100),
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FieldLenField("ipcount", None, count_of="addrlist", fmt="B"),
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ByteField("authtype", 0),
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ByteField("adv", 1),
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XShortField("chksum", None),
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FieldListField("addrlist", [], IPField("", "0.0.0.0"),
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count_from = lambda pkt: pkt.ipcount),
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IntField("auth1", 0),
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IntField("auth2", 0) ]
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def post_build(self, p, pay):
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if self.chksum is None:
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ck = checksum(p)
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p = p[:6]+chb(ck>>8)+chb(ck&0xff)+p[8:]
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return p
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@classmethod
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def dispatch_hook(cls, _pkt=None, *args, **kargs):
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if _pkt and len(_pkt) >= 9:
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ver_n_type = orb(_pkt[0])
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if ver_n_type >= 48 and ver_n_type <= 57: # Version == 3
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return VRRPv3
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return VRRP
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# RFC 5798 - Virtual Router Redundancy Protocol (VRRP) Version 3
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class VRRPv3(Packet):
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fields_desc = [
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BitField("version", 3, 4),
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BitField("type", 1, 4),
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ByteField("vrid", 1),
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ByteField("priority", 100),
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FieldLenField("ipcount", None, count_of="addrlist", fmt="B"),
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BitField("res", 0, 4),
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BitField("adv", 100, 12),
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XShortField("chksum", None),
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# FIXME: addrlist should also allow IPv6 addresses :/
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FieldListField("addrlist", [], IPField("", "0.0.0.0"),
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count_from = lambda pkt: pkt.ipcount)]
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def post_build(self, p, pay):
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if self.chksum is None:
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if isinstance(self.underlayer, IP):
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ck = in4_chksum(112, self.underlayer, p)
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elif isinstance(self.underlayer, IPv6):
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ck = in6_chksum(112, self.underlayer, p)
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else:
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warning("No IP(v6) layer to compute checksum on VRRP. Leaving null")
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ck = 0
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p = p[:6]+chb(ck>>8)+chb(ck&0xff)+p[8:]
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return p
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@classmethod
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def dispatch_hook(cls, _pkt=None, *args, **kargs):
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if _pkt and len(_pkt) >= 16:
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ver_n_type = orb(_pkt[0])
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if ver_n_type < 48 or ver_n_type > 57: # Version != 3
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return VRRP
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return VRRPv3
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# IPv6 is supported only on VRRPv3
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bind_layers( IP, VRRP, proto=IPPROTO_VRRP)
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bind_layers( IP, VRRPv3, proto=IPPROTO_VRRP)
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bind_layers( IPv6, VRRPv3, nh=IPPROTO_VRRP)
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