Re: [RFC v2 6/7] net/af_xdp: load BPF file

[Stephen Hemminger <stephen@networkplumber.org>]

On Thu,  8 Mar 2018 21:52:48 +0800
Qi Zhang <qi.z.zhang@intel.com> wrote:

> +struct bpf_insn prog[] = {
> +	{
> +		.code = 0x85, //call imm
> +		.dst_reg = 0,
> +		.src_reg = 0,
> +		.off = 0,
> +		.imm = BPF_FUNC_xdpsk_redirect,
> +	},
> +	{
> +		.code = 0x95, //exit
> +		.dst_reg = 0,
> +		.src_reg = 0,
> +		.off = 0,
> +		.imm = 0,
> +	},
> +};
> +
> +int load_bpf_file(void)
> +{
> +	int fd;
> +
> +	fd = bpf_load_program(BPF_PROG_TYPE_XDP, prog,
> +			      ARRAY_SIZE(prog),
> +			      "GPL", 0,
> +			      bpf_log_buf, BPF_LOG_BUF_SIZE);

Still have license conflict here. The short bpf program is in BSD code and therefore
is BSD, not GPL. But kernel won't let you load non-GPL programs.

Please check with Intel open source compliance to find a GPL solution.

A possible license safe solution is more complex. You need to provide original program
source for the BPF program under dual clause (GPL-2/BSD-3); then read in that object
file and load it.  A user wishing to exercise their GPL rights can then take your
source file and modify and create new file to load.

Doing this also creates additional GPL issues for appliance vendors using AF_XDP.
They need to make available the source of all these XDP BPF programs.

Complying with mixed licenses is hard.