On Wed, Aug 28, 2019 at 12:07 AM Jiri Pirko <j...@resnulli.us> wrote: > > Tue, Aug 27, 2019 at 05:14:49PM CEST, ro...@cumulusnetworks.com wrote: > >On Tue, Aug 27, 2019 at 2:35 AM Jiri Pirko <j...@resnulli.us> wrote: > >> > >> Tue, Aug 27, 2019 at 10:22:42AM CEST, da...@davemloft.net wrote: > >> >From: Jiri Pirko <j...@resnulli.us> > >> >Date: Tue, 27 Aug 2019 09:08:08 +0200 > >> > > >> >> Okay, so if I understand correctly, on top of separate commands for > >> >> add/del of alternative names, you suggest also get/dump to be separate > >> >> command and don't fill this up in existing newling/getlink command. > >> > > >> >I'm not sure what to do yet. > >> > > >> >David has a point, because the only way these ifnames are useful is > >> >as ways to specify and choose net devices. So based upon that I'm > >> >slightly learning towards not using separate commands. > >> > >> Well yeah, one can use it to handle existing commands instead of > >> IFLA_NAME. > >> > >> But why does it rule out separate commands? I think it is cleaner than > >> to put everything in poor setlink messages :/ The fact that we would > >> need to add "OP" to the setlink message just feels of. Other similar > >> needs may show up in the future and we may endup in ridiculous messages > >> like: > >> > >> SETLINK > >> IFLA_NAME eth0 > >> IFLA_ATLNAME_LIST (nest) > >> IFLA_ALTNAME_OP add > >> IFLA_ALTNAME somereallylongname > >> IFLA_ALTNAME_OP del > >> IFLA_ALTNAME somereallyreallylongname > >> IFLA_ALTNAME_OP add > >> IFLA_ALTNAME someotherreallylongname > >> IFLA_SOMETHING_ELSE_LIST (nest) > >> IFLA_SOMETHING_ELSE_OP add > >> ... > >> IFLA_SOMETHING_ELSE_OP del > >> ... > >> IFLA_SOMETHING_ELSE_OP add > >> ... > >> > >> I don't know what to think about it. Rollbacks are going to be pure hell :/ > > > >I don't see a huge problem with the above. We need a way to solve this > >anyways for other list types in the future correct ?. > >The approach taken by this series will not scale if we have to add a > >new msg type and header for every such list attribute in the future. > > Do you have some other examples in mind? So far, this was not needed.
yes, so far it was not needed. No other future possible examples in mind...but I wont be surprised if we see such cases in the future. Having a consistent API to extend a list attribute will help. > > > > > >A good parallel here is bridge vlan which uses RTM_SETLINK and > >RTM_DELLINK for vlan add and deletes. But it does have an advantage of > >a separate > >msg space under AF_BRIDGE which makes it cleaner. Maybe something > >closer to that can be made to work (possibly with a msg flag) ?. > > 1) Not sure if AF_BRIDGE is the right example how to do things > 2) See br_vlan_info(). It is not an OP-PER-VLAN. You either add or > delete all passed info, depending on the cmd (RTM_SETLINK/RTM_DETLINK). yes, correct. I mentioned that because I was wondering if we can think along the same lines for this API. eg (a) RTM_NEWLINK always replaces the list attribute (b) RTM_SETLINK with NLM_F_APPEND always appends to the list attribute (c) RTM_DELLINK with NLM_F_APPEND updates the list attribute (It could be NLM_F_UPDATE if NLM_F_APPEND sounds weird in the del case. I have not looked at the full dellink path if it will work neatly..its been a busy day ) > > > > > >Would be good to have a consistent way to update list attributes for > >future needs too. > > Okay. Do you suggest to have new set of commands to handle > adding/deleting lists of items? altNames now, others (other nests) later? > > Something like: > > CMD SETLISTS > IFLA_NAME eth0 > IFLA_ATLNAME_LIST (nest) > IFLA_ALTNAME somereallylongname > IFLA_ALTNAME somereallyreallylongname > IFLA_ALTNAME someotherreallylongname > IFLA_SOMETHING_ELSE_LIST (nest) > IFLA_SOMETHING_ELSE > IFLA_SOMETHING_ELSE > IFLA_SOMETHING_ELSE > > > CMD DELLISTS > IFLA_NAME eth0 > IFLA_ATLNAME_LIST (nest) > IFLA_ALTNAME somereallylongname > IFLA_ALTNAME somereallyreallylongname > IFLA_ALTNAME someotherreallylongname > IFLA_SOMETHING_ELSE_LIST (nest) > IFLA_SOMETHING_ELSE > IFLA_SOMETHING_ELSE > IFLA_SOMETHING_ELSE > > How does this sound? This seems fine but it does introduce a new type. If we can avoid a new msg type with a flag that would be nice (like the NLM_F_APPEND eg above). The reason for that is to see if we can use it else where too (eg some random future list attribute in the route subsystem. If a flag works then we don't have to add a RTM_NEWROUTE variant of CMD SETLISTS and CMD DELLISTS)
