Vendor extensions

[diraol]

The VendorHeader class (struct ofp_vendor_header), located at in the symmetric module, exists to build vendor specific extensions messages.

I am in doubt if this class should accept extra attributes, not previously declared, as stated on the specification:

/* Vendor-defined arbitrary additional data. */

[beraldoleal]

Each vendor can implement any struct here. So we should implement like a binary data, and ignore, for now.

[beraldoleal]

@diraol Is easy to make it a binary data, right ?

[diraol]

Yes! I think that this is the solution.
(Knowing closely how the things work make it easier to understand how to solve this problems. =) Long live to practical knowledge!)