Messages in this thread | | | Date | Wed, 1 Dec 2021 12:20:56 -0700 | Subject | Re: [RFC 00/12] io_uring zerocopy send | From | David Ahern <> |
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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
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