On Tue, Jul 28, 2020 at 6:42 PM Xie He <xie.he.0...@gmail.com> wrote: > On Tue, Jul 28, 2020 at 12:52 PM -0700 > Brian Norris <briannor...@chromium.org> wrote: > > What is the intention with this X25 protocol? I guess the headers added > > in lapbeth_data_transmit() are supposed to be "invisible", as with this > > note in af_packet.c? ... > This driver is not intended to be used with IPv4 or IPv6 protocols, > but is intended to be used with a special "X.25" protocol. That's the > reason the device type is ARPHRD_X25. I used "grep" in the X.25 > network layer code (net/x25) and I found there's nowhere > "dev_hard_header" is called. I also used "grep" in all the X.25
That well could just be a bug in net/x25/. But from context, it does appear that X.25 does not intend to expose its headers to higher layers. > drivers in the kernel (lapbether.c, x25_asy.c, hdlc_x25.c under > drivers/net/wan) and I found no driver implemented "header_ops". So I > think the X.25 networking code doesn't expect any header visible > outside of the device driver, and X.25 drivers should make their > headers invisible outside of them. > > So I think hard_header_len should be 0 for all X.25 drivers, so that > they can be used correctly with af_packet.c. > > I don't know if this sounds plausible to you. If it does, could you > please let me have your name in a "Reviewed_by" tag. It would be of > great help to have your support. Thanks! Sure, I can do that: Reviewed-by: Brian Norris <briannor...@chromium.org> I guess x25 is basically an abandoned project, if you're coming to me for this?
