On Wed, Oct 9, 2024 at 9:23 PM Willem de Bruijn <willemdebruijn.kernel@xxxxxxxxx> wrote: > > Jason Xing wrote: > > On Wed, Oct 9, 2024 at 3:19 PM Martin KaFai Lau <martin.lau@xxxxxxxxx> wrote: > > > > > > On 10/8/24 2:51 AM, Jason Xing wrote: > > > > From: Jason Xing <kernelxing@xxxxxxxxxxx> > > > > > > > > Now we allow users to set tsflags through bpf_setsockopt. What I > > > > want to do is passing SOF_TIMESTAMPING_RX_SOFTWARE flag, so that > > > > we can generate rx timestamps the moment the skb traverses through > > > > driver. > > > > > > > > Here is an example: > > > > > > > > case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: > > > > case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: > > > > sock_opt = SOF_TIMESTAMPING_RX_SOFTWARE; > > > > bpf_setsockopt(skops, SOL_SOCKET, SO_TIMESTAMPING, > > > > &sock_opt, sizeof(sock_opt)); > > > > break; > > > > > > > > In this way, we can use bpf program that help us generate and report > > > > rx timestamp. > > > > > > > > Signed-off-by: Jason Xing <kernelxing@xxxxxxxxxxx> > > > > --- > > > > net/core/filter.c | 3 +++ > > > > 1 file changed, 3 insertions(+) > > > > > > > > diff --git a/net/core/filter.c b/net/core/filter.c > > > > index bd0d08bf76bb..9ce99d320571 100644 > > > > --- a/net/core/filter.c > > > > +++ b/net/core/filter.c > > > > @@ -5225,6 +5225,9 @@ static int sol_socket_sockopt(struct sock *sk, int optname, > > > > break; > > > > case SO_BINDTODEVICE: > > > > break; > > > > + case SO_TIMESTAMPING_NEW: > > > > + case SO_TIMESTAMPING_OLD: > > > > > > I believe this change was proposed before. It will change the user expectation > > > on the sk_error_queue. It needs some bits/fields/knobs for bpf. I think this > > > point is similar to other's earlier comments in this thread. > > > > Thanks for your reply. > > > > After seeing what you mentioned, I searched through the mailing list > > and found one [1] which was designed to fetch hardware timestamps. > > > > [1]：https://lore.kernel.org/bpf/51fd5249-140a-4f1b-b20e-703f159e88a3@xxxxxxxxx/T/ > > > > > > > > I only have a chance to briefly look at it. I think it is useful. This > > > bpf/timestamp feature request has come up before. > > > > At the very beginning, I had no intention to use bpf_setsockopt() to > > retrieve the rx timestamp because it will override sk_tsflags, but I > > cannot implement a good way like what I did to tx path: only setting > > skb's field. I'm not sure if this override behaviour is acceptable, so > > I post it to know what the bpf experts' suggestions are. > > > > > > > > A high level comment. The current timestamp should work for non tcp sock? The > > > bpf/timestamp solution should be able to also. > > > > For now, it only supports TCP proto. I would like to quickly implement > > a framework which is also suitable for other protos. TCP is just a > > start point. > > > > > > > > sockops is tcp centric. From looking at patch 9 that needs to initialize 4 args, > > > this interface feels old and not sure we want to extend to other sock types. > > > This needs some thoughts. > > > > For me, I have interests to extend to other sock types. But I'm > > supposed to ask Willem's opinion first. > > > > +Willem de Bruijn Do you want this bpf extension feature to extend to > > other protos? > > There would likely be users for other protocols too, just like > SO_TIMESTAMPING. Though TCP is probably the most widely used case by > far. Agreed !
