* Add netlink definitions for extra IFLAs
The relevant IFLA_* are defined in the kernel but not in the syscall
package.
* Parameterize the return value of loadSimpleBpf
Allow the return value of the bpf program created by loadSimpleBpf to
be specified by the caller. Before this, the value was hardcoded to 1.
* Add support for a new IFLA that enables using a bpf program as a
filter early in the driver path of some NICs.
* Add a test for set/get of an xdp program. Since currently, the XDP
IFLA is optional, check that the hardware supports it before trying to
set the field.
Signed-off-by: Brenden Blanco <bblanco@plumgrid.com>