On Thu, Oct 12, 2017 at 11:44 AM, Anton Ivanov <anton.iva...@cambridgegreys.com> wrote: > Found it. > > Two bugs canceling each other. > The bind sequence in: psock_txring_vnet.c is wrong. > > It does the following addr.sll_protocol = htons(ETH_P_IP); > before calling bind. > > If you set addr.sll_protocol to ETH_P_ALL where it should have been in the > first place the test program blows up with -ENOBUFS
There is no such requirement that the socket should bind to ETH_P_ALL. > I think what is happening is that this value is taken into account when > looking at "what should I use to segment it with" in skb_mac_gso_segment > which is invoked at the end of the verification chain which starts in > packet_direct_xmit in af_packet.c packet_snd sets skb->protocol based on the protocol that the packet socket is bound to. Binding to ETH_P_IP is the right choice here.
