'RELENG_7_0_0_RELEASE'.

This commit was manufactured to restore the state of the 7.0-RELEASE image.

function, pru_close, to notify protocols that the file descriptor or
other consumer of a socket is closing the socket.  pru_abort is now a
notification of close also, and no longer detaches.  pru_detach is no
longer used to notify of close, and will be called during socket
tear-down by sofree() when all references to a socket evaporate after
an earlier call to abort or close the socket.  This means detach is now
an unconditional teardown of a socket, whereas previously sockets could
persist after detach of the protocol retained a reference.

This faciliates sharing mutexes between layers of the network stack as
the mutex is required during the checking and removal of references at
the head of sofree().  With this change, pru_detach can now assume that
the mutex will no longer be required by the socket layer after
completion, whereas before this was not necessarily true.

Reviewed by:	gnn

so they are easier to follow for the human being.

protocol. RFCOMM is a SOCK_STREAM protocol not SOCK_SEQPACKET. This was a
serious bug caused by cut-and-paste. I'm surprised it did not bite me before.
Dunce hat goes to me.

MFC after:	3 days

call net_add_domain(). Calling this function too early (or late) breaks
assertations about the global domains list.
Actually it should be forbidden to call net_add_domain() outside of
SI_SUB_PROTO_DOMAIN completely as there are many places where we traverse
the domains list unprotected, but for now we allow late calls (mostly to
support netgraph). In order to really fix this we have to lock the domains
list in all places or find another way to ensure that we can safely walk the
list while another thread might be adding a new domain.

Spotted by:	se
Reviewed by:	julian, glebius
PR:		kern/73321	(partly)

default elements in net_init_domain().

This makes it possible to grep these structures and see any bogosities.

Reviewed by:	bde, ru

the   MAC label referenced from 'struct socket' in the IPv4 and
IPv6-based protocols.  This permits MAC labels to be checked during
network delivery operations without dereferencing inp->inp_socket
to get to so->so_label, which will eventually avoid our having to
grab the socket lock during delivery at the network layer.

This change introduces 'struct inpcb' as a labeled object to the
MAC Framework, along with the normal circus of entry points:
initialization, creation from socket, destruction, as well as a
delivery access control check.

For most policies, the inpcb label will simply be a cache of the
socket label, so a new protocol switch method is introduced,
pr_sosetlabel() to notify protocols that the socket layer label
has been updated so that the cache can be updated while holding
appropriate locks.  Most protocols implement this using
pru_sosetlabel_null(), but IPv4/IPv6 protocols using inpcbs use
the the worker function in_pcbsosetlabel(), which calls into the
MAC Framework to perform a cache update.

Biba, LOMAC, and MLS implement these entry points, as do the stub
policy, and test policy.

Reviewed by:	sam, bms
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories