geneve creates a generic network virtualization tunnel interface
for Tentant Systems over an L3 (IP/UDP) underlay network that provides
a Layer 2 (ethernet) or Layer 3 service using the geneve protocol.
This implementation is based on RFC8926.

Reviewed by:	glebius, adrian
Discussed with:	zlei, kp
Relnotes:	yes
Differential Revision: https://reviews.freebsd.org/D54172

The change e133271fc1b5e introduced ifnet_detach_sxlock, and change
6d2a10d96fb5 widened its coverage, but there are still consumers,
net80211 and tuntap e.g., want it. Instead of sprinkling it everywhere,
make it opaque to consumers.

Out of tree drivers shall also benefit from this change.

Reviewed by:	kp
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D56298

The ROUTE_MPATH compile option was introduced to
test the new multipath implementation.
Since compiling it has no overhead and it's enabled
by default, remove it.

Reviewed by:	melifaro, markj
Relnotes:	yes
Differential Revision: https://reviews.freebsd.org/D55884

There is no user for `rta_expires` member and it's
duplicate of `rta_expire`.

Reviewed By: melifaro
Differential Revision: https://reviews.freebsd.org/D55445

Before this change, netlink only shows nexthop
expire value if route is not multipath.
Now it can set expire time during route creation.
Also, show expire time of multipath nexthops.

Reviewed by: glebius
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D55442

Migrate to new if_clone KPI and implement netlink support
for gre(4). Also refactor some of the gre specific ioctls.

Reviewed by: glebius, zlei
Differential Revision: https://reviews.freebsd.org/D54443

The entire netlink(4) message processing thread is all inlined into
nl_taskqueue_handler() making it difficult to dtrace(1) on a message
level.

Sockets that implement their own socket buffers (marked with PR_SOCKBUF)
are now also responsible for initialization of socket buffer mutexes in
pr_attach and for destruction in pr_detach (or pr_close).

This removes a big bunch of reported LORs, as now WITNESS is able to see
that tcp(4) socket buffer mutex and netlink(4) socket buffer mutex are two
different things.  Distinct names also improve diagnostics for blocked
threads.

This also removes a hack from unix(4), where we used to mtx_destroy().
Also removes an innocent bug from unix(4) where for accept(2)-ed socket
soreserve() was called twice.  This one was innocent since first call to
soreserve() was asking for 0 bytes of space.

This slightly increased amount of pasted code in TCP's syncache_socket().
The problem is that while for sockets created with socket(2) it is
pr_attach responsible for call to soreserve() (including !PR_SOCKBUF
protocols), but for the sockets created with accept(2) it was
solisten_clone() doing soreserve(), combined with the fact that for
accept(2) TCP completely bypasses pr_attach. This all should improve once
TCP has its own socket buffers.

Reviewed by:		markj
Differential Revision:	https://reviews.freebsd.org/D54984

Add the #include for proc.h which seems to be there in the VIMAGE
case through some other includes only.

Sponsored by:	The FreeBSD Foundation
Fixes:		04f6b99947d2

Make sure rtnl_handle_newlink sets the caller's credential
during calls to ifc_create_ifp_nl and ifc_modify_ifp_nl

Reviewed by: glebius, melifaro
Approved by: glebius (mentor)
Differential Revision: https://reviews.freebsd.org/D54109