The main engine for handling encapsualted packets in packetdrill,
including:

- parsing scripts with encapsulation
- parsing packets with encapsulation
- injecting packets with encapsulation

Encapsulated packets look like the following, which has an IP header,
GRE header, and then regular IP/TCP header:

+0 > ipv4 1.1.1.1 > 2.2.2.2: gre: . 1:1001(1000) ack 1

See other patches in the series for more detailed examples.


Change-Id: Ia8c7580e268f5b0347bd9d3fdc73b096f751a79d

Basic definitions to support GRE-encapsulated packets.


Change-Id: I9c3158d17577c54c3298a65667976a7edab9c184

As a first step for packetdrill supporting encapsulated packets,
introduce types to represent all the layers of headers in a packet.


Change-Id: I617a6b977d4fc1f6a51b1b0211dc2c3b39cc2738

Signed-off-by: Mike Neilsen <mneilsen@acm.org>

Signed-off-by:  <tuexen@fh-muenster.de>

Rewrite an if conditional that clang complained about on FreeBSD 10.x.

Signed-off-by: Neal Cardwell <ncardwell@google.com>

For example, FreeBSD 10.0 beta 3 default installation does not have a
"gcc".

Signed-off-by: Neal Cardwell <ncardwell@google.com>

Ignore .o and ~ files.

Signed-off-by: Neal Cardwell <ncardwell@google.com>

FreeBSD 10.x has fmemopen in libc, so check __FreeBSD_version and set
defines appropriately.

fmemopen(3) states that buffers opened via open_memstream should be
freed after closing the associated stream.

Signed-off-by: Mike Neilsen <mneilsen@acm.org>

Adds initial batch of packetdrill tests that have been confirmed to pass on
stock (Ubuntu) Linux 3.11.0-rc4.

Signed-off-by: Barath Raghavan <barath@google.com>

Initial commit for the packetdrill network stack testing tool:

  https://code.google.com/p/packetdrill/



Signed-off-by: Neal Cardwell <ncardwell@google.com>