Re: [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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.



[Index of Archives]     [Linux Samsung SoC]     [Linux Rockchip SoC]     [Linux Actions SoC]     [Linux for Synopsys ARC Processors]     [Linux NFS]     [Linux NILFS]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]


  Powered by Linux