Tue, Jun 16, 2015 at 01:25:51AM CEST, da...@davemloft.net wrote: >From: sfel...@gmail.com >Date: Sat, 13 Jun 2015 11:04:26 -0700 > >> The switchdev port driver must do two things: >> >> 1) Generate a fwd_mark for each switch port, using some unique key of the >> switch device (and optionally port). This is a one-time operation done >> when port's netdev is setup. >> >> 2) On packet ingress from port, mark the skb with the ingress port's >> fwd_mark. If the device supports it, it's useful to only mark skbs >> which were already forwarded by the device. If the device does not >> support such indication, all skbs can be marked, even if they're >> local dst. >> >> Two new 32-bit fields are added to struct sk_buff and struct netdevice to >> hold the fwd_mark. I've wrapped these with CONFIG_NET_SWITCHDEV for now. I >> tried using skb->mark for this purpose, but ebtables can overwrite the >> skb->mark before the bridge gets it, so that will not work. >> >> In general, this fwd_mark can be used for any case where a packet is >> forwarded by the device and a copy is sent to the CPU, to avoid the kernel >> re-forwarding the packet. sFlow is another use-case that comes to mind, >> but I haven't explored the details. > >Generally I'm against adding new fields fo sk_buff but I'm trying to be >open minded. :-) > >About the per-device fwd_mark, if the key attribute is uniqueness, >let's just do it right and use something like lib/idr.c to generate >truly unique indices at probe time for all devices using this >facility. I like that better than having them be unique by a happy >accident.
We already have per-device uniqueue key. dev->ifindex. That should be good for fwd_mark purposes I believe. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
