On 12/4/20 7:56 PM, Daniel Borkmann wrote:
On 12/3/20 10:33 PM, Florent Revest wrote:This creates a new helper proto because the existing bpf_get_socket_cookie_sock_proto has a ARG_PTR_TO_CTX argument and only works for BPF programs where the context is a sock. This helper could also be useful to other BPF program types such as LSM. Signed-off-by: Florent Revest <revest@xxxxxxxxxx> --- include/uapi/linux/bpf.h | 7 +++++++ kernel/trace/bpf_trace.c | 4 ++++ net/core/filter.c | 7 +++++++ tools/include/uapi/linux/bpf.h | 7 +++++++ 4 files changed, 25 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index c3458ec1f30a..3e0e33c43998 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1662,6 +1662,13 @@ union bpf_attr { * Return * A 8-byte long non-decreasing number. * + * u64 bpf_get_socket_cookie(void *sk) + * Description + * Equivalent to **bpf_get_socket_cookie**\ () helper that accepts + * *sk*, but gets socket from a BTF **struct sock**. + * Return + * A 8-byte long non-decreasing number.I would not mention this here since it's not fully correct and we should avoid users taking non-decreasing granted in their progs. The only assumption you can make is that it can be considered a unique number. See also [0] with reverse counter.. [0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=92acdc58ab11af66fcaef485433fde61b5e32fac
One more thought, in case you plan to use this from sleepable context, you would need to use sock_gen_cookie() variant in the BPF helper instead.
