Re: Issue with iwd + Linux 5.8.3 + WPA Enterprise

From: Denis Kenzior
Date: Wed Aug 26 2020 - 11:34:03 EST


Hi Herbert,

On 8/26/20 9:19 AM, Herbert Xu wrote:
On Wed, Aug 26, 2020 at 08:57:17AM -0500, Denis Kenzior wrote:

I'm just waking up now, so I might seem dense, but for my education, can you
tell me why we need to set MSG_MORE when we issue just a single sendmsg
followed immediately by recv/recvmsg? ell/iwd operates on small buffers, so
we don't really feed the kernel data in multiple send operations. You can
see this in the ell git tree link referenced in Andrew's reply.

You obviously don't need MSG_MORE if you're doing a single sendmsg.

The problematic code is in l_cipher_set_iv. It does a sendmsg(2)
that expects to be followed by more sendmsg(2) calls before a
recvmsg(2). That's the one that needs a MSG_MORE.


Gotcha. I fixed the set_iv part now in ell:
https://git.kernel.org/pub/scm/libs/ell/ell.git/commit/?id=87c76bbc85fe286925cbdb53d733fc9f9fd2ed12

Regards,
-Denis