[ovs-dev] [PATCH] ofp-parse: Fix parsing of "resubmit" action.

[Justin Pettit]

On Jul 19, 2012, at 10:04 AM, Ben Pfaff wrote:

> On Thu, Jul 19, 2012 at 12:45:19AM -0700, Justin Pettit wrote:
>> The new abstraction introduced in commit f25d0cf (Introduce ofpacts, an
>> abstraction of OpenFlow actions.) provides a mechanism for storing the
>> original action type for when converting from the internal representation
>> to a public one may be ambiguous.  The "resubmit" action must
>> distinguish between OFPUTIL_NXAST_RESUBMIT_TABLE and
>> OFPUTIL_NXAST_RESUBMIT, so the parsing function needs to properly fill
>> out the "compat" member of the ofpact structure.
>> 
>> Bug #8899
>> Reported-by: Luca Giraudo <lgiraudo at nicira.com>
>> Signed-off-by: Justin Pettit <jpettit at nicira.com>
> 
> Good catch.
> 
> Hmm.  I hadn't considered this issue when I wrote the ofpacts code.  If
> I understand what's going on, it's essentially that ofpacts that differ
> bitwise can yield the same representation as a string (or as OpenFlow
> 1.0 actions).  That's going to continue to come up, even if we paper
> over it in this one case.
> 
> So, I'd suggest that, instead of comparing ofpacts bytewise, we compare
> some other representation.  We could, for example, format the old rule
> and the new rule as strings, then if they're the same just don't print
> the difference (it's false).  This would avoid printing false
> differences too.

Yes, I think this is a better approach and more future-proof as new actions get added.

> Do you have a test case we could add to the unit tests?

No, I don't have one written up beyond what Luca described in the bug report.

--Justin