bpf: Clarify error expectations from bpf_clone_redirect (4f8c4e16) · Commits · e / devices / android_kernel_fairphone_FP4

[ Upstream commit 7cb779a6867fea00b4209bcf6de2f178a743247d ] Commit 151e887d8ff9 ("veth: Fixing transmit return status for dropped packets") exposed the fact that bpf_clone_redirect is capable of returning raw NET_XMIT_XXX return codes. This is in the conflict with its UAPI doc which says the following: "0 on success, or a negative error in case of failure." Update the UAPI to reflect the fact that bpf_clone_redirect can return positive error numbers, but don't explicitly define their meaning. Reported-by:

Daniel Borkmann <daniel@iogearbox.net> Signed-off-by:

Stanislav Fomichev <sdf@google.com> Signed-off-by:

Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230911194731.286342-1-sdf@google.com Signed-off-by:

Sasha Levin <sashal@kernel.org>

include/uapi/linux/bpf.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -693,7 +693,9 @@ union bpf_attr {
		* performed again, if the helper is used in combination with
		* direct packet access.
		* Return
		* 0 on success, or a negative error in case of failure.
		* 0 on success, or a negative error in case of failure. Positive
		* error indicates a potential drop or congestion in the target
		* device. The particular positive error codes are not defined.
		*
		* u64 bpf_get_current_pid_tgid(void)
		* Return

tools/include/uapi/linux/bpf.h

+3 −1

Original line number	Diff line number	Diff line
		@@ -691,7 +691,9 @@ union bpf_attr {
		* performed again, if the helper is used in combination with
		* direct packet access.
		* Return
		* 0 on success, or a negative error in case of failure.
		* 0 on success, or a negative error in case of failure. Positive
		* error indicates a potential drop or congestion in the target
		* device. The particular positive error codes are not defined.
		*
		* u64 bpf_get_current_pid_tgid(void)
		* Return