Nikolay Aleksandrov
2017-Sep-01 12:03 UTC
[Bridge] [PATCH net] bridge: switchdev: Clear forward mark when transmitting packet
On 01/09/17 15:01, Jiri Pirko wrote:> Fri, Sep 01, 2017 at 01:45:15PM CEST, nikolay at cumulusnetworks.com wrote: >> On 01/09/17 12:22, Ido Schimmel wrote: >>> Commit 6bc506b4fb06 ("bridge: switchdev: Add forward mark support for >>> stacked devices") added the 'offload_fwd_mark' bit to the skb in order >>> to allow drivers to indicate to the bridge driver that they already >>> forwarded the packet in L2. >>> >>> In case the bit is set, before transmitting the packet from each port, >>> the port's mark is compared with the mark stored in the skb's control >>> block. If both marks are equal, we know the packet arrived from a switch >>> device that already forwarded the packet and it's not re-transmitted. >>> >>> However, if the packet is transmitted from the bridge device itself >>> (e.g., br0), we should clear the 'offload_fwd_mark' bit as the mark >>> stored in the skb's control block isn't valid. >>> >>> This scenario can happen in rare cases where a packet was trapped during >>> L3 forwarding and forwarded by the kernel to a bridge device. >>> >>> Fixes: 6bc506b4fb06 ("bridge: switchdev: Add forward mark support for stacked devices") >>> Signed-off-by: Ido Schimmel <idosch at mellanox.com> >>> Reported-by: Yotam Gigi <yotamg at mellanox.com> >>> Tested-by: Yotam Gigi <yotamg at mellanox.com> >>> Reviewed-by: Jiri Pirko <jiri at mellanox.com> >>> --- >>> net/bridge/br_device.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c >>> index 861ae2a165f4..5a7be3bddfa9 100644 >>> --- a/net/bridge/br_device.c >>> +++ b/net/bridge/br_device.c >>> @@ -53,6 +53,9 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev) >>> brstats->tx_bytes += skb->len; >>> u64_stats_update_end(&brstats->syncp); >>> >>> +#ifdef CONFIG_NET_SWITCHDEV >>> + skb->offload_fwd_mark = 0; >>> +#endif >>> BR_INPUT_SKB_CB(skb)->brdev = dev; >>> >>> skb_reset_mac_header(skb); >>> >> >> Good catch, just one minor nit since there is already an ifdef >> switchdev/else in br_private.h, why not make this a helper and avoid the >> ifdef/endif in here ? Currently there is no ifdef switchdev anywhere else. > > I think it would be better to convert this to a helper in -net-next and > take the patch as it is for -net >Either way is fine I guess, it's just more work for something as simple. :-) Whichever way you choose, Acked-by: Nikolay Aleksandrov <nikolay at cumulusnetworks.com>