On Wed, May 27, 2026 at 12:46:25PM -0700, Martin KaFai Lau wrote:

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If this new rcvq callback is added to the 'bpf_tcp_ops' proposal [1],
all this will go away. 'struct sk_buff *skb' can be directly passed to an
ops of the 'bpf_tcp_ops'. Supporting '*skb' in a struct_ops has already
been done in the bpf_qdisc.

[1]: https://lore.kernel.org/bpf/20260519215841.2984970-11-martin.lau@linux.dev/ (local)

Oh I missed the series, the struct_ops conversion looks nice !
Since this work isn't urgent, I can wait for your series if mine
churns it.

Jason's series is adding a new op, and I guess this can be
integrated too ?
https://lore.kernel.org/bpf/20260521135244.40869-5-kerneljasonxing@gmail.com/ (local)

imo, a new sock_ops cb should be added as an ops in struct_ops. For example,
in patch 4 of that series, bpf_skops_rx_timestamping assigns u64 to 'u32
args[4]', which is adding tech debt to the current sock_ops interface.
For the timestamping case, it could be a separate ops for the
'struct sock' instead of 'struct tcp_sock' because it should
at least work for both TCP and UDP.

Sorry, I don't get it. What is the tech debt in this? And
bpf_skops_rx_timestamping() only outputs the timestamps, which has
nothing to do with either 'sock' or 'tcp_sock'.

Did I say the tech debt is in bpf_skops_rx_timestamping?
I said the tech debt of the bpf_sock_ops[_kern] interface.
Besides always memzero the whole &sockops, the way that the bpf prog
needs to get a u64 timestamp from u32 is not thrilling in 2026.
args[4] is also not reliable when the earlier cgroup bpf prog
writes to replylong. We had already hit some of these in our rx net
timestamping discussion a few years ago. I suggest you go back
and revisit.

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Could you show me what to do next? Thanks in advance. It sounds like
the tx side of bpf timestamping should be adjusted accordingly?

imo, the bpf_tcp_ops can land first. and then add net timestamping
ops (existing tx and the new rx) in bpf_sock_ops.

To be clear, for bpf_sock_ops, I meant a struct_ops named bpf_sock_ops (or
another better name).