On Tue, Apr 19, 2022 at 04:06:57PM +0200, Toke Høiland-Jørgensen wrote: > Ondrej Zajicek <santi...@crfreenet.org> writes: > > > On Sat, Apr 16, 2022 at 07:28:59PM +0200, Toke Høiland-Jørgensen wrote: > >> Daniel Gröber <d...@darkboxed.org> writes: > >> > >> > When dumping the routing table bird currently doesn't set the rtm_table > >> > netlink field to select any particular one but rather wants to get all at > >> > once. > >> > > >> > This can be problematic when multiple routing daemons are running on a > >> > system as the kernel's route modification performance goes down > >> > drasticly (by a factor of 20-200ish) when the table is being modified > >> > while > >> > it's being dumped. > >> > > >> > To avoid this situation we make bird do dumps on a per-kernel-table > >> > basis. This then allows the administrator to have multiple routing > >> > daemons > >> > use different kernel tables which sidesteps the problem. > >> > > >> > See also this discussion on the babel-users mailing list: > >> > > >> > https://alioth-lists.debian.net/pipermail/babel-users/2022-April/003902.html > >> > >> Note that this only works with the strict netlink filter checking is > >> enabled (i.e., if the setsockopt for NETLINK_GET_STRICT_CHK succeeds). > >> Bird currently doesn't check this at runtime at all, so just applying > >> this patch as-is will not work correctly on older kernels (<4.20). > > > > I like the idea of scanning tables independently, but i suspected there > > would be an issue on older kernels without NETLINK_GET_STRICT_CHK. > > I will check how hard it would be to switch CONFIG_ALL_TABLES_AT_ONCE > > in run-time. > > The success/failure of the NETLINK_GET_STRICT_CHECK should be a > predictor of whether the filtering will work; this is from the commit > message that added the flag:
Hello Finally i got around to finishing it: https://gitlab.nic.cz/labs/bird/-/commit/534d0a4b44aa193da785ae180475a448f57805e2 It switches CONFIG_ALL_TABLES_AT_ONCE behavior run-time based on success / failure of the setsockopt for NETLINK_GET_STRICT_CHECK. Seems to work correctly on both newer and older systems. There were also some minor issues in the original patch, like not handling table_id > 255, and not setting proper address family for scan. -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: santi...@crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."
