Hi,
don't worry, your english is good enough :)
IPv6 is designed so that you can add multiple headers into a single packet
(basically, that's a different way to implement the old "options" IPv4
header field) and I called "chain" this configuration. What I want to do is
to find a solution for the problem highlighted in this IETF Draft
http://tools.ietf.org/html/draft-ietf-v6ops-ra-guard-implementation-05#section-2.1
2013/10/21 Yuichi Ito <[email protected]>
> Hi, if it is alright, please tell me.
>
>
> On Sat, 19 Oct 2013 18:53:53 +0200
> Gabriele Gerbino <[email protected]> wrote:
>
> Hi,
>> I'm trying to implement a RA Guard-like solution, improving it with the
>> possibility of detect the presence of a RA Header into an extension header
>> chain.
>>
>
> Do you mean that 'RA Header' is 'Router Advertisement message' ?
> If so, it is not related to 'extension headers' in IPv6 header.
> It is one of the type of ICMPv6 messages.
>
>
>
> I can detect it, but seems like there is some problem about the
>> forwarding procedure: if the RA header is the first of chain I can filter
>> it based on the prefix announced (packet dropped if it carries an untrusted
>> prefix, delivered otherwise), but it doesn't work if the RA header is not
>> the first one.
>>
>
> What does 'chain' mean ?
> ICMPv6 messages are not chain structures.
> Do you suggest that operations differ by the existence of 'extension
> headers' ?
>
> I hope that my bad English is understood.
>
>
> I can still drop it based on the prefix, but I cannot deliver it even if
>> the code "goes" into the right "if ramification" and according to that the
>> packet should be flooded, like shown by the LOG
>>
>> Code:
>> def _packet_in_handler(self, ev):
>> msg = ev.msg
>> datapath = msg.datapath
>> ofproto = datapath.ofproto
>> suspicious = 0
>>
>> pkt = packet.Packet(msg.data)
>> eth = pkt.get_protocol(ethernet.**ethernet)
>>
>> dst = eth.dst
>> src = eth.src
>>
>> try:
>> ippiv6 = pkt.get_protocol(ipv6.ipv6)
>> ipv6s = ippiv6.src
>> except:
>> ipv6s = "not assigned yet"
>>
>> print "PACCHETTO ", ippiv6
>> try:
>> icimpv6 = pkt.get_protocol(icmpv6.**icmpv6)
>> icmpv6type = icimpv6.type_
>> except:
>> print "non e' un ICMPv6"
>> icmpv6type = ""
>> if (icmpv6type == 134):
>> icidata = icimpv6.data
>> #self.logger.info <http://self.logger.info>("[**DATA
>> ND_OPTION] %s: ", icidata)
>>
>> print("EXTENSION HEADER: ", ippiv6)
>> print("GNE GNE: ", ippiv6.ext_hdrs)
>> try:
>> dict1 = icidata.data[1]
>> self.logger.info <http://self.logger.info>("[**PREFIX] %s ",
>> dict1.prefix)
>>
>> except:
>> try:
>> dict1 = icidata.data[0]
>> self.logger.info <http://self.logger.info>("[**PREFIX] %s ",
>> dict1.prefix)
>> suspicious = 0
>> except:
>> self.logger.info <http://self.logger.info>("[**ALERT] ND_OPTION_PI not
>> found, irregular structure. Packet Dropped.")
>>
>> dict1=0 #se i due sopra falliscono, gli
>> diamo un intero per l'if sotto.
>> suspicious = 1
>> self.logger.info <http://self.logger.info>("[**SUSPECT] SUSPICIOUS state
>> has changed!")
>>
>> '''if isinstance(dict1, icmpv6.nd_option_pi):
>> self.logger.info <http://self.logger.info>("[**ALERT] I'm IN! :)")
>> else:
>> self.logger.info <http://self.logger.info>("[**ALERT] I'm OUT! :(")'''
>>
>> if isinstance(icidata, icmpv6.nd_router_advert):
>> self.logger.info <http://self.logger.info>("**Router Advert Instance
>> Detected!")
>> suspicious = 0
>>
>> self.logger.info <http://self.logger.info>("[**ALERT] packet contains a
>> Router Advertisement!")
>>
>>
>> if (dict1.prefix not in prefixtrusted):
>> self.logger.info <http://self.logger.info>("[**WARNING] Intrusion
>> Detection System detected a Rogue Router Advertisement!\n %s != %s \n",
>> dict1.prefix, prefixtrusted)
>> suspicious = 1
>> self.logger.info <http://self.logger.info>("[**SUSPECT] SUSPICIOUS state
>> has changed!")
>>
>> dpid = datapath.id <http://datapath.id>
>> self.mac_to_port.setdefault(**dpid, {})
>> self.logger.info <http://self.logger.info>("**packet in %s ipv6:%s %s %s
>> %s", dpid, ipv6s, src, dst, msg.in_port)
>>
>> # learn a mac address to avoid FLOOD next time.
>> self.mac_to_port[dpid][src] = msg.in_port
>>
>> if suspicious:
>> self.logger.info <http://self.logger.info>("\n[**DROP] SUSPICIOUS packet
>> was dropped!")
>>
>> out_port = ofproto.OFPP_NONE
>> elif (dst in self.mac_to_port[dpid]):
>> out_port = self.mac_to_port[dpid][dst]
>> print "OUT_PORT = MAC_TO_PORT"
>> else:
>> out_port = ofproto.OFPP_FLOOD
>> print "FLOOD---------------"
>> self.logger.info <http://self.logger.info> (" %s", out_port)
>>
>> actions = [datapath.ofproto_parser.**OFPActionOutput(out_port)]
>>
>>
>>
>> LOG:
>>
>> PACCHETTO ipv6(dst='ff02::1',ext_hdrs=[**fragment(id_=0,more=0,nxt=58,**
>> offset=0)],flow_label=0,hop_**limit=64,nxt=44,payload_**
>> length=56,src='fe80::200:ff:**fe00:1',traffic_class=0,**version=6)
>> ('EXTENSION HEADER: ', ipv6(dst='ff02::1',ext_hdrs=[**
>> fragment(id_=0,more=0,nxt=58,**offset=0)],flow_label=0,hop_**
>> limit=64,nxt=44,payload_**length=56,src='fe80::200:ff:**
>> fe00:1',traffic_class=0,**version=6))
>> ('GNE GNE: ', [fragment(id_=0,more=0,nxt=58,**offset=0)])
>> [PREFIX] 2001::
>> Router Advert Instance Detected!
>> [ALERT] packet contains a Router Advertisement!
>> packet in 1 ipv6:fe80::200:ff:fe00:1 00:00:00:00:00:01 33:33:00:00:00:01 1
>> FLOOD---------------
>> 65531
>>
>> Scapy:
>> packet = IPv6(dst="ff02::1")/**IPv6ExtHdrFragment()/ICMPv6ND_**
>> RA()/ICMPv6NDOptPrefixInfo(**prefixlen = 64, prefix = "2001::")
>> send(packet)
>>
>>
>> ------------------------------**------------------------------**
>> ------------------
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>>
>>
>>
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>>
>>
>
>
>
------------------------------------------------------------------------------
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Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from
the latest Intel processors and coprocessors. See abstracts and register >
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