Re: [PATCH v2 1/2] udp: UDP socket send queue repair

[Bui Quang Minh]

On 8/11/2021 11:14 PM, Eric Dumazet wrote:
> On 8/11/21 5:45 PM, Bui Quang Minh wrote:
> > In this patch, I implement UDP_REPAIR sockoption and a new path in
> > udp_recvmsg for dumping the corked packet in UDP socket's send queue.
> >
> > A userspace program can use recvmsg syscall to get the packet's data and
> > the msg_name information of the packet. Currently, other related
> > information in inet_cork that are set in cmsg are not dumped.
> >
> > While working on this, I was aware of Lese Doru Calin's patch and got some
> > ideas from it.
>
>
> What is the use case for this feature, adding a test in UDP fast path ?

This feature is used to help CRIU to dump CORKed UDP packet in send queue. I'm 
sorry for being not aware of the performance perspective here.

> IMO, TCP_REPAIR hijacking standard system calls was a design error,
> we should have added new system calls.

You are right that adding new system calls is a better approach. What do you 
think about adding a new option in getsockopt approach?

Thanks,
Quang Minh.