From: David Ahern <dsa@cumulusnetworks.com>
To: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net-next v2 1/2] net: l3mdev: Add hook in ip and ipv6
Date: Sat, 7 May 2016 20:25:40 -0600 [thread overview]
Message-ID: <572EA3A4.9010200@cumulusnetworks.com> (raw)
In-Reply-To: <20160507213205.02529bde@halley>
On 5/7/16 12:32 PM, Shmulik Ladkani wrote:
> Hi David,
>
> On Sat, 7 May 2016 08:50:49 -0600 David Ahern <dsa@cumulusnetworks.com> wrote:
>>>> +static inline
>>>> +struct sk_buff *l3mdev_l3_rcv(struct sk_buff *skb, u16 proto)
>>>> +{
>>>> + struct net_device *master = NULL;
>>>> +
>>>> + if (netif_is_l3_slave(skb->dev))
>>>> + master = netdev_master_upper_dev_get_rcu(skb->dev);
>>>> +
>>>> + else if (netif_is_l3_master(skb->dev))
>>>> + master = skb->dev;
>>>> +
>>>> + if (master && master->l3mdev_ops->l3mdev_l3_rcv)
>>>> + skb = master->l3mdev_ops->l3mdev_l3_rcv(master, skb, proto);
>>>
>>> In the case where netif_is_l3_master(skb->dev) is true, can you explain
>>> why we need to pass it through the l3mdev_l3_rcv callback again?
>>
>> what do you mean again? This is only time the l3mdev_l3_rcv method is
>> called on a packet.
>
> You have the following:
>
> if (netif_is_l3_slave(skb->dev))
> master = netdev_master_upper_dev_get_rcu(skb->dev);
> else if (netif_is_l3_master(skb->dev))
> master = skb->dev;
> if (master && master->l3mdev_ops->l3mdev_l3_rcv)
> skb = master->l3mdev_ops->l3mdev_l3_rcv(master, skb, proto);
>
> So in both conditions (skb->dev being the slave or the master) the skb
> is passed to master's l3mdev_l3_rcv callback.
>
> Appreciate if you can elaborate:
> - Why callback needs to be invoked when skb->dev is the L3 master?
Every l3mdev_ops has converged on that ordering -- if l3 slave else if
l3 master.
> - On which circumstances we end up entering
> l3mdev_ip_rcv/l3mdev_ip6_rcv where skb->dev is the master?
> If I got it right, we enter 'ip_rcv_finish' on a slave device,
> the callback is invoked and eventually sets skb->dev and skb->skb_iif
> to the VRF device; then ip_rcv_finish continues processing the
> altered skb (with the changed skb->dev).
> So on which cicumstances do we enter 'ip_rcv_finish' where the
> skb->dev is ALREADY a master device?
If you look at the full patchset I posted on 5/4 the patch after PKTINFO
allows local traffic. That change needs the netif_is_l3_master().
next prev parent reply other threads:[~2016-05-08 2:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-07 1:49 [PATCH net-next v2 0/2] net: vrf: Fixup PKTINFO to return enslaved device index David Ahern
2016-05-07 1:49 ` [PATCH net-next v2 1/2] net: l3mdev: Add hook in ip and ipv6 David Ahern
2016-05-07 8:30 ` Shmulik Ladkani
2016-05-07 14:50 ` David Ahern
2016-05-07 18:32 ` Shmulik Ladkani
2016-05-08 2:25 ` David Ahern [this message]
2016-05-08 5:44 ` Shmulik Ladkani
2016-05-07 1:49 ` [PATCH net-next 2/2] net: original ingress device index in PKTINFO David Ahern
2016-05-07 8:41 ` Shmulik Ladkani
2016-05-07 14:53 ` David Ahern
2016-05-07 19:08 ` Shmulik Ladkani
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