On Tue, Nov 28, 2017 at 3:46 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Tue, Nov 28, 2017 at 8:04 AM, Björn Töpel <bjorn.topel@xxxxxxxxx> wrote: >> 2017-11-27 21:51 GMT+01:00 Arnd Bergmann <arnd@xxxxxxxx>: >> [...] >>>> There already is an effort to come up with a new AF_PACKET V4 [1]. >>>> We should make sure that any new interface does not have the >>>> Y2038/Y2106 issue. But, if a new version is being developed and >>>> that subsumes all existing use cases, then there probably is no need >>>> for another version that is a very small diff to V3. >>> >>> Ah, perfect, that's good timing. Adding Björn to Cc here. >>> >> >> Unfortunately, for the Y2038/Y2106 cases, we'll be (as a result of >> netdevconf discussions) moving the AF_PACKET V4 implementation to a >> separate, new, address/packet family. > > Ok, I see. Does it matter whether the replacement is a new version or a new packet family? >>>> If adding support for existing applications is useful, another approach >>>> would be to add a new socket option that changes the semantics for >>>> the two u32 fields in each of V1, V2 and V3 to hold nsec. Add a single >>>> check after filling in those structs whether the option is set and, if so, >>>> overwrite the two fields. >>>> >>>> [1] https://lwn.net/Articles/737947/ >>> >>> I don't think that's necessary. As long as the V4 capabilities are a >>> superset of V1-V3, we should be able to just require all users to >>> move to V4 (or later) in the next 89 years, and make sure that they >>> use unsigned seconds if they care about 2038. >>> >> >> Given that V4 wont be around for AF_PACKET -- at least not in the >> shape of our patches -- Willem's suggestion is probably a good way >> forward. > > That leaves one question: should we do that now, or wait until some > other reason for a V4 comes up? I don't mind creating another > patch for this, just want to get a feeling of whether the API clutter > is worth it when we have a way out that works until y2106 (at > which point we run into other problems as well). I don't expect that we'll have another packet version independent from the work that Björn is doing. The choice to implement using a new packet family is given by the complexity of the existing code, especially the various locking mechanisms. >From that point of view, and if we want to offer a Y2106 proof AF_PACKET independent from the above, no reason to wait. -- To unsubscribe from this list: send the line "unsubscribe linux-kselftest" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
