On Mon, Apr 28, 2014 at 12:00 AM, Simon Horman <ho...@verge.net.au> wrote: > On Fri, Apr 25, 2014 at 12:57:20PM -0700, Jesse Gross wrote: >> On Fri, Apr 25, 2014 at 1:06 AM, YAMAMOTO Takashi >> <yamam...@valinux.co.jp> wrote: >> >> On Thu, Apr 24, 2014 at 05:57:29PM +0900, YAMAMOTO Takashi wrote: >> >>> hi, >> >>> >> >>> > + * Due to the sample action there may be multiple possible eth types. >> >>> > + * In order to correctly validate actions all possible types are >> >>> > tracked >> >>> > + * and verified. This is done using struct eth_types. >> >>> >> >>> is there any real-world use cases of these actions inside a sample? >> >>> otherwise, how about just rejecting such combinations? >> >>> it doesn't seem to worth the code complexity to me. >> >>> (sorry if it has been already discussed. it's the first time for me >> >>> to seriously read this long-lived patch.) >> >> >> >> Good point, the code is rather complex. >> >> >> >> My understanding is that it comes into effect in the case >> >> of sflow or ipfix being configured on the bridge. I tend >> >> to think these are real-world use-cases, though that thinking >> >> is by no means fixed. >> >> >> >> My reading of the code is that in the case of sflow and ipfix a single >> >> sample rule appears at the beginning of the flow. And that it may be >> >> possible to replace the code that you are referring to with something >> >> simpler to handle these cases. >> > >> > it seems that they put only a userland action inside a sample. >> > it's what i expected from its name "sample". >> >> Yes, that's the only current use case. In theory, this could be used >> more generally although nothing has come up yet. >> >> In retrospect, I regret the design of the sample action - not the part >> that allows it to handle different actions but the fact that the >> results can affect things outside of the sample action list. I think >> that if we had made it more like a subroutine then that would have >> retained all of the functionality but none of the complexity here. >> Perhaps if we can find a clean way to restructure it without breaking >> compatibility then that would simplify the validation here. > > I have not thought deeply about this but it seems to me that it should be > easy enough to provide compatibility for a new user-space to work with both > new and old datapaths. But it is not clear to me how to achieve the > reverse: allowing a new datapath to work with both new and old user-spaces. > I assume that we care about such compatibility.
Generally, I would say yes although there is potentially some room for debate here. No version of OVS userspace has ever put an action other than userspace in the sample field. I know that other people have talked about writing different userspaces that run on the OVS kernel module but I highly doubt that they use this action or would do so differently. I can't prove that but it might be OK to bite the bullet. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev