Commit f5c79ffd authored May 05, 2025 by Paul Chaignon Committed by Jakub Kicinski May 07, 2025

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>

parent c4327229

include/uapi/linux/bpf.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -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

tools/include/uapi/linux/bpf.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -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