On Wed, Feb 02, 2022 at 02:10:15PM -0700, Shuah Khan wrote: > On 2/2/22 1:16 PM, Guillaume Nault wrote: > > On Wed, Feb 02, 2022 at 12:46:10PM -0700, Shuah Khan wrote: > > > On 2/2/22 11:30 AM, Guillaume Nault wrote: > > > > Although both iproute2 and the kernel accept 1 and 2 as tos values for > > > > new routes, those are invalid. These values only set ECN bits, which > > > > are ignored during IPv4 fib lookups. Therefore, no packet can actually > > > > match such routes. This selftest therefore only succeeds because it > > > > doesn't verify that the new routes do actually work in practice (it > > > > just checks if the routes are offloaded or not). > > > > > > > > It makes more sense to use tos values that don't conflict with ECN. > > > > This way, the selftest won't be affected if we later decide to warn or > > > > even reject invalid tos configurations for new routes. > > > > > > Wouldn't it make sense to leave these invalid values in the test though. > > > Removing these makes this test out of sync withe kernel. > > > > Do you mean keeping the test as is and only modify it when (if) we > > decide to reject such invalid values? > > This is for sure. Remove the invalid values in sync with the kernel code. > > > Or to write two versions of the > > test, one with invalid values, the other with correct ones? > > > > This one makes sense if it adds value in testing to make sure we continue > to reject invalid values. > > > I don't get what keeping a test with the invalid values could bring us. > > It's confusing for the reader, and might break in the future. This > > patch makes the test future proof, without altering its intent and code > > coverage. It still works on current (and past) kernels, so I don't see > > what this patch could make out of sync. > > > > If kernel still accepts these values, then the test is valid as long as > kernel still doesn't flag these values as invalid. > > I might be missing something. Don't you want to test with invalid values > so make sure they are indeed rejected? Testing invalid values makes sense, but in another selftest IMHO. This file is used to test hardware offload behaviour (although it lives under selftests/net/, it's only called from other scripts living under selftests/drivers/). Testing for accepted/rejected values should be done in a network generic selftest, not in driver specific ones. I'm currently working on a patch series that'd include such tests (as part of a larger project aimed at fixing conflicting interpretations of ECN bits). But for fib_offload_lib.sh, I'd really prefer if we could keep it focused on testing driver features. > > thanks, > -- Shuah >
