[ovs-discuss] truncate "max_len" assertion in output action

Iwase Yusuke iwase.yusuke0 at gmail.com
Thu Sep 28 02:32:27 UTC 2017


Hi Team,

I'm testing the interoperability of Open vSwitch v2.8.0 (v2.8.90) and Ryu,
and I found the some problems to run a basic application of Ryu
(ryu/app/simple_switch_13.py) with this version of OVS.

With the following patch, assertions of "max_len" when do output action
in xlate_output_action() function were introduced.
https://github.com/openvswitch/ovs/commit/119385781336dabeb29410fb5036302f726c6f05#diff-8bbf76f24a1b6618ed3aaaccad70a0a5R4832
But this seems to cause the lack of the interoperability with Ryu.

On Ryu, the default of "max_len" is OFPCML_MAX, even if "port" is other
than OFPP_CONTROLLER;
https://github.com/osrg/ryu/blob/3c22bf414453cc2200155b38272b9a50cd898a65/ryu/ofproto/ofproto_v1_3_parser.py#L2996
So when Ryu indicates the packets to flood to OVS, the assertion of
"truncate" raises errors, then vswitchd will abort.

OpenFlow Spec does not clarify "max_len" value when "port" is other than
OFPP_CONTROLLER, and I guess it should not assert "max_len == 0", just
should be ignored.

Can these assertions be removed? What do you think about this?

Thanks,
Iwase


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