Fanouts allow packet capturing to be demuxed to a set of AF_PACKET
sockets. Two fanout policies are implemented:
1) Hashing based upon skb->rxhash
2) Pure round-robin
An AF_PACKET socket must be fully bound before it tries to add itself
to a fanout. All AF_PACKET sockets trying to join the same fanout
must all have the same bind settings.
Fanouts are identified (within a network namespace) by a 16-bit ID.
The first socket to try to add itself to a fanout with a particular
ID, creates that fanout. When the last socket leaves the fanout
(which happens only when the socket is closed), that fanout is
destroyed.
Signed-off-by: David S. Miller <davem@davemloft.net>
dc99f60069