unix,sunos: prefer SO_REUSEPORT for load balancing (#4733)

Solaris 11.4 has Load Balancing for SO_REUSEPORT, but setting
SO_REUSEADDR disables load balancing.  As per comments in
test/test-udp-reuseport.c prefer SO_REUSEPORT when available.

With these changes in place udp-reuseport testing passes.  BIND (named),
which uses routing sockets which cause ENOPROTOOPT to be returned when
SO_REUSEPORT is requested, also continues to work with the change.

Notes:
- The use of getsockopt() to query if SO_REUSEPORT was available was
  erroneous.
- Selectively limiting SO_REUSEPORT setting to specific types of socket
  was considered but not entertained.
- Oracle will investigate if the setting of SO_REUSEADDR was
  intentionally meant to prevent load balancing.
- Adding a test for routing sockets is left for future work.

0 files changed, 0 insertions, 0 deletions