Messages in this thread | | | Date | Mon, 30 Jun 2014 13:39:31 -0700 | Subject | Re: [PATCH RFC net-next 07/14] bpf: expand BPF syscall with program load/unload | From | Alexei Starovoitov <> |
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On Sat, Jun 28, 2014 at 8:35 AM, Andy Lutomirski <luto@amacapital.net> wrote: > On Sat, Jun 28, 2014 at 8:21 AM, Greg KH <gregkh@linuxfoundation.org> wrote: >> On Sat, Jun 28, 2014 at 12:26:14AM -0700, Alexei Starovoitov wrote: >>> On Fri, Jun 27, 2014 at 11:28 PM, Andy Lutomirski <luto@amacapital.net> wrote: >>> > On Fri, Jun 27, 2014 at 11:12 PM, Alexei Starovoitov <ast@plumgrid.com> wrote: >>> > If you want to add GPL-only functions in the future, that would be one >>> > thing. But if someone writes a nice eBPF compiler, and someone else >>> > writes a little program that filters on network packets, I see no >>> > reason to claim that the little program is a derivative work of the >>> > kernel and therefore must be GPL. >>> >>> I think we have to draw a line somewhere. Say, tomorrow I want >>> to modify libpcap to emit eBPF based on existing tcpdump syntax. >>> Would it mean that tcpdump filter strings are GPLed? Definitely not, >>> since they existed before and can function without new libpcap. >>> But if I write a new packet filtering program in C, compile it >>> using LLVM->eBPF and call into in-kernel helper functions >>> (like bpf_map_lookup_elem()), I think it's exactly the derivative work. >>> It's analogous to kernel modules. If module wants to call >>> export_symbol_gpl() functions, it needs to be GPLed. Here all helper >>> functions are GPL. So we just have a blank check for eBPF program. >> >> I agree, these eBFP programs should be GPL-compatible licensed as well. > > I think I'd be happy with an export_symbol_gpl analogue. I might > argue that bpf_map_lookup_elem shouldn't be gpl-only, though.
ok. sounds like module-like approach will be more acceptable to potential user base. Will change it. Last thing I want to do is to scary users away.
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