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. -- 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
