5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stanislav Fomichev <sdf@xxxxxxxxxx>
[ 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@xxxxxxxxxxxxx>
Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20230911194731.286342-1-sdf@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/uapi/linux/bpf.h | 4 +++-
tools/include/uapi/linux/bpf.h | 4 +++-
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index cb0631098f918..e5250a9b813d6 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -780,7 +780,9 @@ 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
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index cb0631098f918..e5250a9b813d6 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -780,7 +780,9 @@ 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
--
2.40.1
