Merge branch 'xdpsock'

Jay Jayatheerthan says:

====================
This series of patches enhances xdpsock application with command line
parameters to set transmit packet size and fill pattern among other options.
The application has also been enhanced to use Linux Ethernet/IP/UDP header
structs and calculate IP and UDP checksums.

I have measured the performance of the xdpsock application before and after
this patch set and have not been able to detect any difference.

Packet Size:
------------
There is a new option '-s' or '--tx-pkt-size' to specify the transmit packet
size. It ranges from 47 to 4096 bytes. Default packet size is 64 bytes
which is same as before.

Fill Pattern:
-------------
The transmit UDP payload fill pattern is specified using '-P' or
'--tx-pkt-pattern'option. It is an unsigned 32 bit field and defaulted
to 0x12345678.

Packet Count:
-------------
The number of packets to send is specified using '-C' or '--tx-pkt-count'
option. If it is not specified, the application sends packets forever.

Batch Size:
-----------
The batch size for transmit, receive and l2fwd features of the application is
specified using '-b' or '--batch-size' options. Default value when this option
is not provided is 64 (same as before).

Duration:
---------
The application supports '-d' or '--duration' option to specify number of
seconds to run. This is used in tx, rx and l2fwd features. If this option is
not provided, the application runs for ever.
====================
Tested-by: Björn Töpel <bjorn.topel@intel.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>