Re: [lwip-users] Are recv/send/write reentrant if LWIP_NETCONN_FULLDUPLEX enabled?

[address@hidden]

Am 17.11.2021 um 18:16 schrieb Grant Edwards:
> My (newly generated 2.1.3) documentation says that
> LWIP_NETCONN_FULLDUPLEX "allows reading from one thread, writing from
> a 2nd thread and closing from a 3rd thread". [And the "really alpha"
> statement is indeed gone.]
>
> I assume that does not imply that recv/send/write are renntrant such
> that two threads could write to a socket/netconn at the same time? Two
> sockets reading at the same time is less common, but would be another
> example.
>
> This situation doesn't really make much sense for TCP, but I have seen
> applications where it is done for UDP and raw Ethernet.

I'd have to re-check the sources, but it should not be a problem for UDP
and raw I guess (as long as CORE_LOCKING is enabled): the problems
mainly come from TCP writes that can't be executed in one batch (so
you'll have to wait for more window or buffers being available). UDP TX
is lock, send, unlock, so that should work. And if it doesn't, it should
be easy to fix.

Regards,
Simon