Remove /^\s*\*+\s*\$FreeBSD\$.*$\n/

Similar commit in current:
(cherry picked from commit 2ff63af9b88c)

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with:		pfg
MFC After:		3 days
Sponsored by:		Netflix

(cherry picked from commit 4d846d260e2b9a3d4d0a701462568268cbfe7a5b)

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

version.

This commit contains mostly refactoring, a few fixes and minor added
functionality.

Submitted by:	Vincenzo Maffione <v.maffione at gmail.com>
Requested by:	many
Sponsored by:	Rubicon Communications, LLC (Netgate)

This commit, long overdue, contains contributions in the last 2 years
from Stefano Garzarella, Giuseppe Lettieri, Vincenzo Maffione, including:
+ fixes on monitor ports
+ the 'ptnet' virtual device driver, and ptnetmap backend, for
  high speed virtual passthrough on VMs (bhyve fixes in an upcoming commit)
+ improved emulated netmap mode
+ more robust error handling
+ removal of stale code
+ various fixes to code and documentation (some mixup between RX and TX
  parameters, and private and public variables)

We also include an additional tool, nmreplay, which is functionally
equivalent to tcpreplay but operating on netmap ports.

Mostly bugfixes or features developed in the past 6 months,
so this is a 10.1 candidate.

Basically no user API changes (some bugfixes in sys/net/netmap_user.h).

In detail:

1. netmap support for virtio-net, including in netmap mode.
  Under bhyve and with a netmap backend [2] we reach over 1Mpps
  with standard APIs (e.g. libpcap), and 5-8 Mpps in netmap mode.

2. (kernel) add support for multiple memory allocators, so we can
  better partition physical and virtual interfaces giving access
  to separate users. The most visible effect is one additional
  argument to the various kernel functions to compute buffer
  addresses. All netmap-supported drivers are affected, but changes
  are mechanical and trivial

3. (kernel) simplify the prototype for *txsync() and *rxsync()
  driver methods. All netmap drivers affected, changes mostly mechanical.

4. add support for netmap-monitor ports. Think of it as a mirroring
  port on a physical switch: a netmap monitor port replicates traffic
  present on the main port. Restrictions apply. Drive carefully.

5. if_lem.c: support for various paravirtualization features,
  experimental and disabled by default.
  Most of these are described in our ANCS'13 paper [1].
  Paravirtualized support in netmap mode is new, and beats the
  numbers in the paper by a large factor (under qemu-kvm,
  we measured gues-host throughput up to 10-12 Mpps).

A lot of refactoring and additional documentation in the files
in sys/dev/netmap, but apart from #2 and #3 above, almost nothing
of this stuff is visible to other kernel parts.

Example programs in tools/tools/netmap have been updated with bugfixes
and to support more of the existing features.

This is meant to go into 10.1 so we plan an MFC before the Aug.22 deadline.

A lot of this code has been contributed by my colleagues at UNIPI,
including Giuseppe Lettieri, Vincenzo Maffione, Stefano Garzarella.

MFC after:	3 days.

so it is easier to buil the same code on linux
(this generalizes the change in svn 267142)

MFC after:	3 days

Most relevant features:

- netmap emulation on any NIC, even those without native netmap support.

  On the ixgbe we have measured about 4Mpps/core/queue in this mode,
  which is still a lot more than with sockets/bpf.

- seamless interconnection of VALE switch, NICs and host stack.

  If you disable accelerations on your NIC (say em0)

        ifconfig em0 -txcsum -txcsum

  you can use the VALE switch to connect the NIC and the host stack:

        vale-ctl -h valeXX:em0

  allowing sharing the NIC with other netmap clients.

- THE USER API HAS SLIGHTLY CHANGED (head/cur/tail pointers
  instead of pointers/count as before). This was unavoidable to support,
  in the future, multiple threads operating on the same rings.
  Netmap clients require very small source code changes to compile again.
      On the plus side, the new API should be easier to understand
  and the internals are a lot simpler.

The manual page has been updated extensively to reflect the current
features and give some examples.

This is the result of work of several people including Giuseppe Lettieri,
Vincenzo Maffione, Michio Honda and myself, and has been financially
supported by EU projects CHANGE and OPENLAB, from NetApp University
Research Fund, NEC, and of course the Universita` di Pisa.

- netmap.c		base code
- netmap_freebsd.c	FreeBSD-specific code
- netmap_generic.c	emulate netmap over standard drivers
- netmap_mbq.c		simple mbuf tailq
- netmap_mem2.c		memory management
- netmap_vale.c		VALE switch

simplify devce-specific code