Some of these changes are a bit rough and will become
more polished later. the changes to if_ethersubr should largely be moved
to within the appletalk code, but that will happen later.
A few of these were related to network-byteorder problems,
and more were related to loopback failures.
by a protocol, to detirmine if an address matches the net this address
is part of. This is needed by protocols for which netmasks
"just don't work", for example appletalk.
Also add the code in appletalk to make use of this new feature.
Thsi fixes one of the longest standing bugs in appletalk.
The inability to talk to machines to which the path is via a router
which is on a different net, but the same netrange, as your interface.
Protocols that do not supply this function (e.g. IP) should not be affected.
Kernel Appletalk protocol support
both CAP and netatalk can make use of this..
still needs some owrk but it seemd the right tiime to commit it
so other can experiment.
