lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Fri, 28 Feb 2020 11:10:30 +0100 From: Toke Høiland-Jørgensen <toke@...hat.com> To: David Ahern <dahern@...italocean.com>, Jesper Dangaard Brouer <brouer@...hat.com>, David Ahern <dsahern@...nel.org> Cc: netdev@...r.kernel.org, davem@...emloft.net, kuba@...nel.org, prashantbhole.linux@...il.com, jasowang@...hat.com, mst@...hat.com, toshiaki.makita1@...il.com, daniel@...earbox.net, john.fastabend@...il.com, ast@...nel.org, kafai@...com, songliubraving@...com, yhs@...com, andriin@...com, dsahern@...il.com Subject: Re: [PATCH RFC v4 bpf-next 03/11] xdp: Add xdp_txq_info to xdp_buff David Ahern <dahern@...italocean.com> writes: > On 2/27/20 4:58 AM, Toke Høiland-Jørgensen wrote: >> also, an egress program may want to actually know which >> ingress iface the packet was first received on. So why not just keep >> both fields? Since ifindex 0 is invalid anyway, the field could just be >> 0 when it isn't known (e.g., egress ifindex on RX, or ingress ifindex if >> it comes from the stack)? > > Today, the ingress device is lost in the conversion from xdp_buff to > xdp_frame. The plumbing needed to keep that information is beyond the > scope of this set. > > I am open to making the UAPI separate entries if there is a real reason > for it. Do you have a specific use case? I was thinking it could be a nice shorthand for whether a packet comes from the local stack or was forwarded (0 == stack). But no, I don't have a concrete application where this is useful. However, if we define it as a union we lose the ability to change our mind. Together with the debugability issue I just replied with to your other email, I think it would be better to expend the four bytes keep them as separate fields, but still restrict access to the RX ifindex for now. -Toke
Powered by blists - more mailing lists