an explicit action for INET6 configuration happens. The changes are:
1. When an ND6 flag is changed via SIOCSIFINFO_FLAGS ioctl,
setting ND6_IFF_ACCEPT_RTADV and/or ND6_IFF_AUTO_LINKLOCAL now triggers
an attempt to clear the ND6_IFF_IFDISABLED flag.
2. When an AF_INET6 address is added successfully to an interface and
it is marked as ND6_IFF_IFDISABLED, an attempt to clear the
ND6_IFF_IFDISABLED happens.
This simplifies ND6_IFF_IFDISABLED flag manipulation by users via ifconfig(8);
in most cases manual configuration is no longer needed.
- When ND6_IFF_AUTO_LINKLOCAL is set and no link-local address is assigned to
an interface, SIOCSIFINFO_FLAGS ioctl now calls in6_ifattach() to configure
a link-local address.
This change ensures link-local address configuration when "ifconfig IF inet6"
command is invoked. For example, "ifconfig IF inet6 auto_linklocal" now
always try to configure an LL addr even if ND6_IFF_AUTO_LINKLOCAL is already
set to 1 (i.e. down/up cycle is no longer needed).
Reviewed by: bz