inpcb: apply smr_advance(9)/smr_wait(9) trick only to reusable sockets

[glebius]

Summary

The protocols marked with PR_CONNREQUIRED can never go through pr_connect
after being disconnected. This is a tiny improvement of fdb987bebddf0.

[markj]

This removes the smr_advance() calls, but also the clearing of the addr/port. Is it intentional?

[glebius]

I don't see a point in clearing the addresses either. Speculatively (didn't check!) it should even fix getsockname(2) on a disconnected TCP connection.

[markj]

In D55661#1274834, @glebius wrote:

I don't see a point in clearing the addresses either. Speculatively (didn't check!) it should even fix getsockname(2) on a disconnected TCP connection.

I don't see much point either, but the code has done this since at least 1994. But ok, I think this change is functionally a no-op anyway, since only the UDP code uses these functions...?

sys/netinet6/in6_pcb.c

512–513

This comment applies to the smr_advance() call, so should be moved to make that more clear. Same thing above.

[glebius]

Adjust comment placement per Mark's suggestion.

[pouria]

I'll write a manual for in_pcb someday...

sys/netinet/in_pcb.c

1436–1442

style

sys/netinet6/in6_pcb.c

513–520

[markj]

sys/netinet/in_pcb.c

1436–1442

+1

[glebius]

Use == 0 to check flags.

[markj]

In D55661#1274968, @markj wrote:

In D55661#1274834, @glebius wrote:

I don't see a point in clearing the addresses either. Speculatively (didn't check!) it should even fix getsockname(2) on a disconnected TCP connection.

I don't see much point either, but the code has done this since at least 1994. But ok, I think this change is functionally a no-op anyway, since only the UDP code uses these functions...?

The commit log message should mention this aspect of the change.