On 14/10/2024 21:34, Eric Woudstra wrote:
>
>
> On 10/14/24 8:59 AM, Nikolay Aleksandrov wrote:
>> On 13/10/2024 21:55, Eric Woudstra wrote:
>>> New function dev_fill_bridge_path(), similar to dev_fill_forward_path().
>>> It handles starting from a bridge port instead of the bridge master.
>>> The structures ctx and nft_forward_info need to be already filled in with
>>> the (vlan) encaps.
>>>
>>> Signed-off-by: Eric Woudstra <ericwouds@xxxxxxxxx>
>>> ---
>>> include/linux/netdevice.h | 2 +
>>> net/core/dev.c | 77 ++++++++++++++++++++++++++++++++-------
>>> 2 files changed, 66 insertions(+), 13 deletions(-)
>>>
>>> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>>> index e87b5e488325..9d80f650345e 100644
>>> --- a/include/linux/netdevice.h
>>> +++ b/include/linux/netdevice.h
>>> @@ -3069,6 +3069,8 @@ void dev_remove_offload(struct packet_offload *po);
>>>
>>> int dev_get_iflink(const struct net_device *dev);
>>> int dev_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb);
>>> +int dev_fill_bridge_path(struct net_device_path_ctx *ctx,
>>> + struct net_device_path_stack *stack);
>>> int dev_fill_forward_path(const struct net_device *dev, const u8 *daddr,
>>> struct net_device_path_stack *stack);
>>> struct net_device *__dev_get_by_flags(struct net *net, unsigned short flags,
>>> diff --git a/net/core/dev.c b/net/core/dev.c
>>> index cd479f5f22f6..49959c4904fc 100644
>>> --- a/net/core/dev.c
>>> +++ b/net/core/dev.c
>>> @@ -713,44 +713,95 @@ static struct net_device_path *dev_fwd_path(struct net_device_path_stack *stack)
>>> return &stack->path[k];
>>> }
>>>
>>> -int dev_fill_forward_path(const struct net_device *dev, const u8 *daddr,
>>> - struct net_device_path_stack *stack)
>>> +static int dev_fill_forward_path_common(struct net_device_path_ctx *ctx,
>>> + struct net_device_path_stack *stack)
>>> {
>>> const struct net_device *last_dev;
>>> - struct net_device_path_ctx ctx = {
>>> - .dev = dev,
>>> - };
>>> struct net_device_path *path;
>>> int ret = 0;
>>>
>>> - memcpy(ctx.daddr, daddr, sizeof(ctx.daddr));
>>> - stack->num_paths = 0;
>>> - while (ctx.dev && ctx.dev->netdev_ops->ndo_fill_forward_path) {
>>> - last_dev = ctx.dev;
>>> + while (ctx->dev && ctx->dev->netdev_ops->ndo_fill_forward_path) {
>>> + last_dev = ctx->dev;
>>> path = dev_fwd_path(stack);
>>> if (!path)
>>> return -1;
>>>
>>> memset(path, 0, sizeof(struct net_device_path));
>>> - ret = ctx.dev->netdev_ops->ndo_fill_forward_path(&ctx, path);
>>> + ret = ctx->dev->netdev_ops->ndo_fill_forward_path(ctx, path);
>>> if (ret < 0)
>>> return -1;
>>>
>>> - if (WARN_ON_ONCE(last_dev == ctx.dev))
>>> + if (WARN_ON_ONCE(last_dev == ctx->dev))
>>> return -1;
>>> }
>>>
>>> - if (!ctx.dev)
>>> + if (!ctx->dev)
>>> return ret;
>>>
>>> path = dev_fwd_path(stack);
>>> if (!path)
>>> return -1;
>>> path->type = DEV_PATH_ETHERNET;
>>> - path->dev = ctx.dev;
>>> + path->dev = ctx->dev;
>>> +
>>> + return ret;
>>> +}
>>> +
>>> +int dev_fill_bridge_path(struct net_device_path_ctx *ctx,
>>> + struct net_device_path_stack *stack)
>>> +{
>>> + const struct net_device *last_dev, *br_dev;
>>> + struct net_device_path *path;
>>> + int ret = 0;
>>> +
>>> + stack->num_paths = 0;
>>> +
>>> + if (!ctx->dev || !netif_is_bridge_port(ctx->dev))
>>> + return -1;
>>> +
>>> + br_dev = netdev_master_upper_dev_get_rcu((struct net_device *)ctx->dev);
>>> + if (!br_dev || !br_dev->netdev_ops->ndo_fill_forward_path)
>>> + return -1;
>>> +
>>> + last_dev = ctx->dev;
>>> + path = dev_fwd_path(stack);
>>> + if (!path)
>>> + return -1;
>>> +
>>> + memset(path, 0, sizeof(struct net_device_path));
>>> + ret = br_dev->netdev_ops->ndo_fill_forward_path(ctx, path);
>>> + if (ret < 0)
>>> + return -1;
>>> +
>>> + if (!ctx->dev || WARN_ON_ONCE(last_dev == ctx->dev))
>>> + return -1;
* ^^^^^^^^^ here
>>> +
>>> + if (!netif_is_bridge_master(ctx->dev))
>>
>> hmm, do we expect ctx->dev to be a bridge master? Looking at
>> br_fill_forward_path, it seems to be == fdb->dst->dev which
>> should be the target port
>
> It would indeed be very unlikely. It was a left-over from code I wrote,
> thinking that here I could handle cascaded bridges (via vlan-device). I
> dropped that, since conntrack does not follow this flow.
>
> So would it be better to only make sure that ctx->dev is not a bridge
> master?
>
> if (netif_is_bridge_master(ctx->dev))
> return -1;
>
> return dev_fill_forward_path_common(ctx, stack);
>
I think you misunderstood me, I don't think ctx->dev can ever be a bridge
device because ctx->dev gets set to fdb->dst and fdbs that point to the bridge
itself have fdb->dst == NULL but ctx->dev is checked against NULL earlier*
so the bridge dev check doesn't make sense to me.
>>> + return dev_fill_forward_path_common(ctx, stack);
>>> +
>>> + path = dev_fwd_path(stack);
>>> + if (!path)
>>> + return -1;
>>> + path->type = DEV_PATH_ETHERNET;
>>> + path->dev = ctx->dev;
>>>
>>> return ret;
>>> }
>>> +EXPORT_SYMBOL_GPL(dev_fill_bridge_path);
>>> +
>>> +int dev_fill_forward_path(const struct net_device *dev, const u8 *daddr,
>>> + struct net_device_path_stack *stack)
>>> +{
>>> + struct net_device_path_ctx ctx = {
>>> + .dev = dev,
>>> + };
>>> +
>>> + memcpy(ctx.daddr, daddr, sizeof(ctx.daddr));
>>> +
>>> + stack->num_paths = 0;
>>> +
>>> + return dev_fill_forward_path_common(&ctx, stack);
>>> +}
>>> EXPORT_SYMBOL_GPL(dev_fill_forward_path);
>>>
>>> /**
>>
