On 2019/01/06 0:55, William Tu wrote:
...
>>> + /* put into rq */
>>> + skb = veth_xdp_rcv_one(rq, xdpf, &inner_xdp_xmit);
>>> + if (!skb) {
>>> + /* Peer side has XDP program attached */
>>> + if (inner_xdp_xmit & VETH_XDP_TX) {
>>> + /* Not supported */
>>> + pr_warn("veth: peer XDP_TX not supported\n");
>>
>> As this can be triggered by users we need ratelimit at least.
> How to rate limit here? Can I slow down the napi poll or reduce the budget?
net_ratelimit()
>> But since this is envisioned to be used in OVS, XDP_TX would be a very
>> important feature to me. I expect XDP programs in containers to process
>> packets and send back to OVS.
>
> It's a little tricky here since the receiving veth pulls the packet sent from
> its peer side, but due to XDP_TX, it has to put the packet back to its peer
> side to receive. But I can see the use case you mentioned. Let me think
> about how to implement.
You have already implemented XDP_REDIRECT. XDP_TX is kind of special
case of XDP_REDIRECT, so I wonder why you think XDP_TX is especially
difficult.
--
Toshiaki Makita
