On Sat, 18 Oct 2014 16:03:41 +0200
Benjamin Eggerstedt <[email protected]> wrote:
> Hi Ryu-Team,
>
> I noticed the following on one of my laboratory networks.
>
> If you run the simple_switch_13.py application and you receive an LLDP
> packet that is truncated you'll receive an AssertionError. I have attached
> a packet capture of the concerning packets and the following behaviour seen
> on console.
>
> *Packet capture taken with:*
> $ sudo tcpdump -lnni eth0 -s 0 -w filename.pcap
> (-s 0 lets tcpdump default to 65535, so it means to capture the full packet)
>
> *Console log:*
> $ ryu-manager --verbose ryu/ryu/app/simple_switch_13.py
> loading app ryu/ryu/app/simple_switch_13.py
> loading app ryu.controller.ofp_handler
> instantiating app ryu/ryu/app/simple_switch_13.py of SimpleSwitch13
> instantiating app ryu.controller.ofp_handler of OFPHandler
> BRICK SimpleSwitch13
> CONSUMES EventOFPPacketIn
> CONSUMES EventOFPSwitchFeatures
> BRICK ofp_event
> PROVIDES EventOFPPacketIn TO {'SimpleSwitch13': set(['main'])}
> PROVIDES EventOFPSwitchFeatures TO {'SimpleSwitch13': set(['config'])}
> CONSUMES EventOFPPortDescStatsReply
> CONSUMES EventOFPSwitchFeatures
> CONSUMES EventOFPEchoRequest
> CONSUMES EventOFPHello
> CONSUMES EventOFPErrorMsg
> connected socket:<eventlet.greenio.GreenSocket object at 0x7f45515d7fd0>
> address:('192.168.120.71', 32962)
> hello ev <ryu.controller.ofp_event.EventOFPHello object at 0x7f45515ea510>
> move onto config mode
> EVENT ofp_event->SimpleSwitch13 EventOFPSwitchFeatures
> switch features ev version: 0x4 msg_type 0x6 xid 0x5d6c86fd
> OFPSwitchFeatures(auxiliary_id=0,capabilities=79,datapath_id=537554655993737,n_buffers=256,n_tables=3)
> move onto main mode
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:f4:7a:fd e8:e7:32:51:5f:89 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:f4:7a:fd e8:e7:32:51:5f:89 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:f4:7a:fd e8:e7:32:51:5f:89 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> hub: uncaught exception: Traceback (most recent call last):
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/hub.py", line 52, in
> _launch
> func(*args, **kwargs)
> File "/usr/local/lib/python2.7/dist-packages/ryu/base/app_manager.py",
> line 274, in _event_loop
> handler(ev)
> File "/home/alu4u/ryu/ryu/app/simple_switch_13.py", line 69, in
> _packet_in_handler
> pkt = packet.Packet(msg.data)
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/packet/packet.py",
> line 45, in __init__
> self._parser(parse_cls)
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/packet/packet.py",
> line 51, in _parser
> proto, cls, rest_data = cls.parser(rest_data)
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/packet/lldp.py",
> line 132, in parser
> tlv = cls._tlv_parsers[tlv_type](buf)
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/packet/lldp.py",
> line 336, in __init__
> super(SystemDescription, self).__init__(buf, *args, **kwargs)
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/packet/lldp.py",
> line 89, in __init__
> assert len(buf) >= self.len + LLDP_TLV_SIZE
> AssertionError
>
> ###
>
> The packet in question is #31 of the packet capture (attached). This is my
> upstream switch sending me some information via LLDP (but it appears to be
> truncated to 128 bytes as it is buffered).
>
> I added a print statements and the assert fails as 61 is not equal or
> greater than 76.
>
> *Edited in:*
> /usr/local/lib/python2.7/dist-packages/ryu/lib/packet/lldp.py
>
> *Console log (with my print statements):*
> $ ryu-manager --verbose ryu/ryu/app/simple_switch_13.py
> loading app ryu/ryu/app/simple_switch_13.py
> loading app ryu.controller.ofp_handler
> instantiating app ryu/ryu/app/simple_switch_13.py of SimpleSwitch13
> instantiating app ryu.controller.ofp_handler of OFPHandler
> BRICK SimpleSwitch13
> CONSUMES EventOFPSwitchFeatures
> CONSUMES EventOFPPacketIn
> BRICK ofp_event
> PROVIDES EventOFPSwitchFeatures TO {'SimpleSwitch13': set(['config'])}
> PROVIDES EventOFPPacketIn TO {'SimpleSwitch13': set(['main'])}
> CONSUMES EventOFPHello
> CONSUMES EventOFPPortDescStatsReply
> CONSUMES EventOFPEchoRequest
> CONSUMES EventOFPSwitchFeatures
> CONSUMES EventOFPErrorMsg
> connected socket:<eventlet.greenio.GreenSocket object at 0x7fabcd9fbed0>
> address:('192.168.120.71', 33301)
> hello ev <ryu.controller.ofp_event.EventOFPHello object at 0x7fabcda0e410>
> move onto config mode
> EVENT ofp_event->SimpleSwitch13 EventOFPSwitchFeatures
> switch features ev version: 0x4 msg_type 0x6 xid 0xbfe66b2e
> OFPSwitchFeatures(auxiliary_id=0,capabilities=79,datapath_id=537554655993737,n_buffers=256,n_tables=3)
> move onto main mode
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:f4:7a:fd e8:e7:32:51:5f:89 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:f4:7a:fd e8:e7:32:51:5f:89 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:f4:7a:fd e8:e7:32:51:5f:89 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:c8:6b:21 01:80:c2:00:00:00 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> packet in 537554655993737 00:e0:b1:f4:7a:fd e8:e7:32:51:5f:89 1
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> self.typelen = 519
> LLDP_TLV_LENGTH_MASK = 511
> self.len = 7
> len(buf) = 114
> self.len + LLDP_TLV_SIZE = 9
> self.typelen = 1029
> LLDP_TLV_LENGTH_MASK = 511
> self.len = 5
> len(buf) = 105
> self.len + LLDP_TLV_SIZE = 7
> self.typelen = 1538
> LLDP_TLV_LENGTH_MASK = 511
> self.len = 2
> len(buf) = 98
> self.len + LLDP_TLV_SIZE = 4
> self.typelen = 2067
> LLDP_TLV_LENGTH_MASK = 511
> self.len = 19
> len(buf) = 94
> self.len + LLDP_TLV_SIZE = 21
> self.typelen = 2570
> LLDP_TLV_LENGTH_MASK = 511
> self.len = 10
> len(buf) = 73
> self.len + LLDP_TLV_SIZE = 12
>
>
>
>
> *self.typelen = 3146LLDP_TLV_LENGTH_MASK = 511self.len = 74len(buf) =
> 61self.len + LLDP_TLV_SIZE = 76*
> hub: uncaught exception: Traceback (most recent call last):
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/hub.py", line 52, in
> _launch
> func(*args, **kwargs)
> File "/usr/local/lib/python2.7/dist-packages/ryu/base/app_manager.py",
> line 274, in _event_loop
> handler(ev)
> File "/home/alu4u/ryu/ryu/app/simple_switch_13.py", line 69, in
> _packet_in_handler
> pkt = packet.Packet(msg.data)
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/packet/packet.py",
> line 45, in __init__
> self._parser(parse_cls)
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/packet/packet.py",
> line 51, in _parser
> proto, cls, rest_data = cls.parser(rest_data)
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/packet/lldp.py",
> line 137, in parser
> tlv = cls._tlv_parsers[tlv_type](buf)
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/packet/lldp.py",
> line 341, in __init__
> super(SystemDescription, self).__init__(buf, *args, **kwargs)
> File "/usr/local/lib/python2.7/dist-packages/ryu/lib/packet/lldp.py",
> line 94, in __init__
> assert len(buf) >= self.len + LLDP_TLV_SIZE
> AssertionError
>
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
> EVENT ofp_event->SimpleSwitch13 EventOFPPacketIn
>
> ###
>
> W
> here does the issue come from?
>
> a) The OF switch should not send an apparently truncated packet?
I think so unless such flow is installed. What flows are installed on
your switch?
> b) The lldp.py needs to handle this?
Yeap, it should. I'll take care of it shortly.
> c) I should avoid receiving LLDP with simple_switch_13.py?
If you know what you want to receive, you could use:
https://github.com/osrg/ryu/blob/master/ryu/lib/ofp_pktinfilter.py
> My switch is supposed to work up to the specs of OF v1.3.1 and when I
> reviewed page 92 (Appendix 4.1 Packet In), it appears that it is allowed to
> truncate the packet down to 128 bytes (which is what is part of DATA in
> packet #31) if it is buffered.
>
> I'm running Ryu 3.13 on this host.
> $ ryu-manager --version
> ryu-manager 3.13
>
>
> Just in case the mailing-list doesn't allow me to attach a file, you can
> also get it from the following URL:
> https://ale.files.wimi.pro/download.php?id=30176716&code=7hjy6rcnfios808kcgk4s0ss8
>
> Thanks,
> Regards,
> Benny
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