This commits adds support for the SO_REUSEPORT socket option.
The implementation follows the behavior of BSD and tries to also follow
the specific additional features of linux with the following
limitations:
* SO_REUSEADDR and SO_REUSEPORT are not "the same" for client sockets,
as we do not have a trivial way so identify a socket as "client"
during binding. To get the Linux behavior, one has to use SO_REUSEPORT
with Zephyr
* No prevention of "port hijacking"
* No support for the load balancing stuff for incoming
packets/connections
There is also a new Kconfig option to control this feature, which is
enabled by default if TCP or UDP is enabled.
Signed-off-by: Tobias Frauenschläger <t.frauenschlaeger@me.com>
dcc63120cf