On 11/11/2020 21:37, Pablo Neira Ayuso wrote:
> Add .ndo_fill_forward_path for bridge devices.
>
> Signed-off-by: Pablo Neira Ayuso <pa...@netfilter.org>
> ---
> include/linux/netdevice.h | 1 +
> net/bridge/br_device.c | 24 ++++++++++++++++++++++++
> 2 files changed, 25 insertions(+)
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index ca8525a1a797..d26de9a3d382 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -836,6 +836,7 @@ typedef u16 (*select_queue_fallback_t)(struct net_device
> *dev,
> enum net_device_path_type {
> DEV_PATH_ETHERNET = 0,
> DEV_PATH_VLAN,
> + DEV_PATH_BRIDGE,
> };
>
> struct net_device_path {
> diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
> index 387403931a63..4c3a5334abe0 100644
> --- a/net/bridge/br_device.c
> +++ b/net/bridge/br_device.c
> @@ -391,6 +391,29 @@ static int br_del_slave(struct net_device *dev, struct
> net_device *slave_dev)
> return br_del_if(br, slave_dev);
> }
>
> +static int br_fill_forward_path(struct net_device_path_ctx *ctx,
> + struct net_device_path *path)
> +{
> + struct net_bridge_fdb_entry *f;
> + struct net_bridge_port *dst;
> + struct net_bridge *br;
> +
> + if (netif_is_bridge_port(ctx->dev))
> + return -1;
> +
> + br = netdev_priv(ctx->dev);
> + f = br_fdb_find_rcu(br, ctx->daddr, 0);
> + if (!f || !f->dst)
> + return -1;
> +
> + dst = READ_ONCE(f->dst);
While this is ok, I meant that you have to test the ptr after. In theory between
the !f->dst test above and now it could've become null, so to make it
future-proof
please test the null dst after deref, after the READ_ONCE(). I realize currently
there are still problems after the change but we'll fix them.
> + path->type = DEV_PATH_BRIDGE;
> + path->dev = dst->br->dev;
> + ctx->dev = dst->dev;
> +
> + return 0;
> +}
> +
> static const struct ethtool_ops br_ethtool_ops = {
> .get_drvinfo = br_getinfo,
> .get_link = ethtool_op_get_link,
> @@ -425,6 +448,7 @@ static const struct net_device_ops br_netdev_ops = {
> .ndo_bridge_setlink = br_setlink,
> .ndo_bridge_dellink = br_dellink,
> .ndo_features_check = passthru_features_check,
> + .ndo_fill_forward_path = br_fill_forward_path,
> };
>
> static struct device_type br_type = {
>
