bpf: Clarify handling of mark and tstamp by redirect_peer

When switching network namespaces with the bpf_redirect_peer helper, the
skb->mark and skb->tstamp fields are not zeroed out like they can be on
a typical netns switch. This patch clarifies that in the helper
description.

Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/ccc86af26d43c5c0b776bcba2601b7479c0d46d0.1746460653.git.paul.chaignon@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 28705ae677849f841937040d4c976196e7fb3c87..fd404729b1154bb8b3b6149ea269ca549c0f6990 100644 (file)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -4968,6 +4968,9 @@ union bpf_attr {
  *             the netns switch takes place from ingress to ingress without
  *             going through the CPU's backlog queue.
  *
+ *             *skb*\ **->mark** and *skb*\ **->tstamp** are not cleared during
+ *             the netns switch.
+ *
  *             The *flags* argument is reserved and must be 0. The helper is
  *             currently only supported for tc BPF program types at the
  *             ingress hook and for veth and netkit target device types. The

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 28705ae677849f841937040d4c976196e7fb3c87..fd404729b1154bb8b3b6149ea269ca549c0f6990 100644 (file)
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -4968,6 +4968,9 @@ union bpf_attr {
  *             the netns switch takes place from ingress to ingress without
  *             going through the CPU's backlog queue.
  *
+ *             *skb*\ **->mark** and *skb*\ **->tstamp** are not cleared during
+ *             the netns switch.
+ *
  *             The *flags* argument is reserved and must be 0. The helper is
  *             currently only supported for tc BPF program types at the
  *             ingress hook and for veth and netkit target device types. The