Re: [RFC 00/12] io_uring zerocopy send
flat view
From: David Ahern <hidden>
Date: 2021-12-01 19:21:10
Also in:
io-uring, lkml
On 12/1/21 12:11 PM, Pavel Begunkov wrote:
btw, why a dummy device would ever go through loopback? It doesn't seem to make sense, though may be missing something.
You are sending to a local ip address, so the fib_lookup returns RTN_LOCAL. The code makes dev_out the loopback: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/tree/net/ipv4/route.c#n2773 (you are not using vrf so ignore the l3mdev reference). loopback device has the logic to put the skb back in the stack for Rx processing: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/tree/drivers/net/loopback.c#n68