From: Vincent Bernat <redacted>
Date: Wed, 25 Jul 2018 13:19:13 +0200

When freebind feature is set of an IPv6 socket, any source address can
be used when sending UDP datagrams using IPv6 PKTINFO ancillary
message. Global non-local bind feature was added in commit
35a256fee52c ("ipv6: Nonlocal bind") for IPv6. This commit also allows
IPv6 source address spoofing when non-local bind feature is enabled.

Signed-off-by: Vincent Bernat <redacted>

This definitely seems to make sense.  And is consistent with the other
tests involving freebind and transparent.

This test involving ip_nonlocal_bind, freeebind, and transparent happens
in several locations.  Perhaps we should add a helper function for this?

Thanks.