Implement reserved OFP port FLOOD

[mentels]

FLOOD port when used as an output port sends the packet out all standard
ports, but not the ingress port, nor ports that are in BLOCKED state
(OpenFlow spec. v1.3.2 ch. 4.5).
This behavior is required as NOX 1.3 controller uses this FLOOD port.
(Motivated by #171).

[nygge]

This should not be done. 1.3.2 ch 4.5 says
"OpenFlow-only switches do not support the NORMAL port and FLOOD port, ..."

[legoscia]

This could be done with ets:foldl instead of ets:tab2list + lists:foldl.

[legoscia]

Some code nitpicking, which in no way invalidates Anders' objection.

[mentels]

@nygge I'm aware of what the spec says. But the case is that we want LINC be able to talk with NOX 1.3 controller. Unfortunately this controller use FLOOD port without investigating any PORT_DESCRIPTION from the switch - it just assumes that this FLOOD port exists.

To sum up: we don't want LINC to be hybrid switch, we want it to work with NOX on mininet. We can create report this bug and hope that guys from NOX will fix it. Then we can remove this code for flooding. What do you think?

@legoscia thanks for the remarks.

[nygge]

The flood port is used to send a packet on all ports of the legacy,
non-openflow, part of a hybrid switch. To send on all ports of an openflow
switch use the ALL port.

Depending on what NOX is trying to do I see to possible fixes
1, does it do output to both FLOOD and ALL, if that is the case ignore it
2, treat it as ALL, then there is no need for all the new code in the pull
request

But in both cases report the bug to NOX

/Anders

On Wed, Oct 16, 2013 at 8:43 AM, Szymon Mentel [email protected]:

@nygge https://github.com/nygge I'm aware of what the spec says. But
the case is that we want LINC be able to talk with NOX 1.3 controller.
Unfortunately this controller use FLOOD port without investigating any
PORT_DESCRIPTION from the switch - it just assumes that this FLOOD port
exists.

To sum up: we don't want LINC to be hybrid switch, we want it to work with
NOX on mininet. We can create report this bug and hope that guys from NOX
will fix it. Then we can remove this code for flooding. What do you think?

@legoscia https://github.com/legoscia thanks for the remarks.

—
Reply to this email directly or view it on GitHubhttps://github.com//pull/183#issuecomment-26418365
.

[mentels]

@nygge thanks for you comment. I'll just "redirect" traffic from FLOOD port to the ALL one and mark this solution as temporary in the code. I'll also report the bug to NOX and we will remove the code when it's fixed.

[mentels]

Commit introduced in this pull request should be reverted when the bug CPqD/nox13oflib#3 is fixed.