Add socket.SO_REUSEPORT_LB and use it in socket.create_server(reuse_port=True) and BaseEventLoop.create_server(reuse_port=True)

[graingert]

Feature or enhancement

Proposal:

SO_REUSEPORT_LB is defined in freebsd: https://man.freebsd.org/cgi/man.cgi?setsockopt(2)

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

Linked PRs

• gh-124761: add socket.SO_REUSEPORT_LB #124961

[graingert]

On some platforms eg Darwin/freebsd socket.create_server(reuse_port=True) doesn't actually allow the port to be reused: only one socket that refuses the port can actually receive traffic. I'd like to be able to indicate my need for load balancing behaviour and get an exception on platforms where it's unavailable

[graingert]

This needs support in create_server before closing

[kumaraditya303]

Ah, sorry I missed that.