On 11/04/2022 21:18, Nikolay Aleksandrov wrote: > On 11/04/2022 21:08, Roopa Prabhu wrote: >> >> On 4/11/22 10:29, Nikolay Aleksandrov wrote: >>> Hi, >>> This patch-set adds support to specify filtering conditions for a flush >>> operation. This version has entirely different entry point (v1 had >>> bridge-specific IFLA attribute, here I add new RTM_FLUSHNEIGH msg and >>> netdev ndo_fdb_flush op) so I'll give a new overview altogether. >>> After me and Ido discussed the feature offlist, we agreed that it would >>> be best to add a new generic RTM_FLUSHNEIGH with a new ndo_fdb_flush >>> callback which can be re-used for other drivers (e.g. vxlan). >>> Patch 01 adds the new RTM_FLUSHNEIGH type, patch 02 then adds the >>> new ndo_fdb_flush call. With this structure we need to add a generic >>> rtnl_fdb_flush which will be used to do basic attribute validation and >>> dispatch the call to the appropriate device based on the NTF_USE/MASTER >>> flags (patch 03). Patch 04 then adds some common flush attributes which >>> are used by the bridge and vxlan drivers (target ifindex, vlan id, ndm >>> flags/state masks) with basic attribute validation, further validation >>> can be done by the implementers of the ndo callback. Patch 05 adds a >>> minimal ndo_fdb_flush to the bridge driver, it uses the current >>> br_fdb_flush implementation to flush all entries similar to existing >>> calls. Patch 06 adds filtering support to the new bridge flush op which >>> supports target ifindex (port or bridge), vlan id and flags/state mask. >>> Patch 07 converts ndm state/flags and their masks to bridge-private flags >>> and fills them in the filter descriptor for matching. Finally patch 08 >>> fills in the target ifindex (after validating it) and vlan id (already >>> validated by rtnl_fdb_flush) for matching. Flush filtering is needed >>> because user-space applications need a quick way to delete only a >>> specific set of entries, e.g. mlag implementations need a way to flush only >>> dynamic entries excluding externally learned ones or only externally >>> learned ones without static entries etc. Also apps usually want to target >>> only a specific vlan or port/vlan combination. The current 2 flush >>> operations (per port and bridge-wide) are not extensible and cannot >>> provide such filtering. >>> >>> I decided against embedding new attrs into the old flush attributes for >>> multiple reasons - proper error handling on unsupported attributes, >>> older kernels silently flushing all, need for a second mechanism to >>> signal that the attribute should be parsed (e.g. using boolopts), >>> special treatment for permanent entries. >>> >>> Examples: >>> $ bridge fdb flush dev bridge vlan 100 static >>> < flush all static entries on vlan 100 > >>> $ bridge fdb flush dev bridge vlan 1 dynamic >>> < flush all dynamic entries on vlan 1 > >>> $ bridge fdb flush dev bridge port ens16 vlan 1 dynamic >>> < flush all dynamic entries on port ens16 and vlan 1 > >>> $ bridge fdb flush dev ens16 vlan 1 dynamic master >>> < as above: flush all dynamic entries on port ens16 and vlan 1 > >>> $ bridge fdb flush dev bridge nooffloaded nopermanent self >>> < flush all non-offloaded and non-permanent entries > >>> $ bridge fdb flush dev bridge static noextern_learn >>> < flush all static entries which are not externally learned > >>> $ bridge fdb flush dev bridge permanent >>> < flush all permanent entries > >>> $ bridge fdb flush dev bridge port bridge permanent >>> < flush all permanent entries pointing to the bridge itself > >>> >>> Note that all flags have their negated version (static vs nostatic etc) >>> and there are some tricky cases to handle like "static" which in flag >>> terms means fdbs that have NUD_NOARP but *not* NUD_PERMANENT, so the >>> mask matches on both but we need only NUD_NOARP to be set. That's >>> because permanent entries have both set so we can't just match on >>> NUD_NOARP. Also note that this flush operation doesn't treat permanent >>> entries in a special way (fdb_delete vs fdb_delete_local), it will >>> delete them regardless if any port is using them. We can extend the api >>> with a flag to do that if needed in the future. >>> >>> Patch-sets (in order): >>> - Initial flush infra and fdb flush filtering (this set) >>> - iproute2 support >>> - selftests >>> >>> Future work: >>> - mdb flush support (RTM_FLUSHMDB type) >>> >>> Thanks to Ido for the great discussion and feedback while working on this. >>> >> Cant we pile this on to RTM_DELNEIGH with a flush flag ?. >> >> It is a bulk del, and sounds seems similar to the bulk dev del discussion on netdev a few months ago (i dont remember how that api ended up to be. unless i am misremembering). >> >> neigh subsystem also needs this, curious how this api will work there. >> >> (apologies if you guys already discussed this, did not have time to look through all the comments) >> >> >> > > I thought about that option, but I didn't like overloading delneigh like that. > del currently requires a mac address and we need to either signal the device supports> a null mac, or we should push that verification to ndo_fdb_del users. Also we'll have that's the only thing, overloading delneigh with a flush-behaviour (multi-del or whatever) would require to push the mac check to ndo_fdb_del implementers I don't mind going that road if others agree that we should do it through delneigh + a bit/option to signal flush, instead of a new rtm type. > attributes which are flush-specific and will work only when flushing as opposed to when > deleting a specific mac, so handling them in the different cases can become a pain. scratch the specific attributes, those can be adapted for both cases > MDBs will need DELMDB to be modified in a similar way. > > IMO a separate flush op is cleaner, but I don't have a strong preference. > This can very easily be adapted to delneigh with just a bit more mechanical changes > if the mac check is pushed to the ndo implementers. > > FLUSHNEIGH can easily work for neighs, just need another address family rtnl_register > that implements it, the new ndo is just for PF_BRIDGE. :) > > Cheers, > Nik > >
