When using local mode on *BSD, using the tun0 device was hard
coded in contrast to Linux, where the next unused tun device
was used.
This patch changes the behaviour on *BSD to use the next unused
tun device. This also requires that the device is removed when
packetdrill terminates. This was the case on Linux, but not on
*BSD.
On *BSD there is also a new command line option (--tun-dev) to
set the device name and not select an ephemerial one.

Sponsored by:	Netlix, Inc.

Sponsored by:	Netflix, Inc.

This allows to support a mixture of encapsulated and non-encapsulated
packets in a single script file.

Sponsored by:	Netflix, Inc.

Ensure sequence numbers are mapped correctly.

This adds support for SCTP/UDP and TCP/UDP including ICMP
support.

Sponsored by:	Netflix, Inc.

Improve debugging

Wrap the run time deubg option in a compile time option. (DEBUG)

Merge gnns changes to make the debug mode run time selectable.

First cut at making debug mode run time selectable

On FreeBSD IPv6 sockets have the IPV6_V6ONLY option enabled by
default. To allow the scripts to select the address family
via the --ip_version option transparently, disable the
IPV6_V6ONLY option implicilty on all sockets.
This fixes #132.

Sponsored by:	Netflix, Inc.

Fix remote mode

This fixes #114 and also the TCP remote mode.

Sync with nplab/packetdrill

Sponsored by:	Netflix, Inc.

Sponsored by:	Netflix, Inc.

Sync from nplab/packetdrill

Merge pull request #1 from nplab/master

This is based on a patch from Jason Eggleston with minor modifications
from me.

See https://github.com/google/packetdrill/commit/47582211690ffc2a7f40c371c19d283b2df26a44#diff-9b9398b17ceeb5025735f4c20d63a3e5L547

Improve timing and fix a race condition