lkml.org 
[lkml]   [2014]   [Jun]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH RFC net-next 07/14] bpf: expand BPF syscall with program load/unload
    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.
    Something like "look up the uid that opened a port," on the other
    hand, maybe should be.

    --Andy


    \
     
     \ /
      Last update: 2014-06-28 17:41    [W:2.802 / U:0.120 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site