Support hw SCM_TSTAMP_SND case for bpf timestamping.
Add a new sock_ops callback, BPF_SOCK_OPS_TSTAMP_SND_HW_CB. This
callback will occur at the same timestamping point as the user
space's hardware SCM_TSTAMP_SND. The BPF program can use it to
get the same SCM_TSTAMP_SND timestamp without modifying the
user-space application.
To avoid increasing the code complexity, replace SKBTX_HW_TSTAMP
with SKBTX_HW_TSTAMP_NOBPF instead of changing numerous callers
from driver side using SKBTX_HW_TSTAMP. The new definition of
SKBTX_HW_TSTAMP means the combination tests of socket timestamping
and bpf timestamping. After this patch, drivers can work under the
bpf timestamping.
Considering some drivers don't assign the skb with hardware
timestamp, this patch does the assignment and then BPF program
can acquire the hwstamp from skb directly.
Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250220072940.99994-9-kerneljasonxing@gmail.com
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