1 files changed, 32 insertions, 1 deletions

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 2f1d24fef857..8b41c365ddf9 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -3532,6 +3532,31 @@ union bpf_attr {
  *			Use the mark present in *params*->mark for the fib lookup.
  *			This option should not be used with BPF_FIB_LOOKUP_DIRECT,
  *			as it only has meaning for full lookups.
+ *		**BPF_FIB_LOOKUP_VLAN**
+ *			If the fib lookup resolves to a VLAN device whose
+ *			parent is a real (non-VLAN) device, set
+ *			*params*->h_vlan_proto and *params*->h_vlan_TCI from
+ *			the VLAN device and replace *params*->ifindex with the
+ *			parent's ifindex. *params*->h_vlan_TCI carries the VID
+ *			only, with PCP and DEI bits zero; a consumer wanting to
+ *			set egress priority writes PCP itself. *params*->smac is
+ *			the VLAN device's own address, which can differ from the
+ *			parent's. Only the immediate parent is resolved; if it
+ *			is itself a VLAN device (QinQ) or in another namespace,
+ *			the egress cannot be reduced to a physical device plus
+ *			one tag and the lookup returns
+ *			**BPF_FIB_LKUP_RET_VLAN_FAILURE** with *params*->ifindex
+ *			left at the input. To obtain the VLAN device's own
+ *			ifindex, repeat the lookup without
+ *			**BPF_FIB_LOOKUP_VLAN**, re-initializing *params*
+ *			first: output fields overwrite the inputs they share
+ *			storage with. The swap and the vlan fields
+ *			are written only on success; other output fields keep
+ *			the helper's existing behaviour, so a frag-needed result
+ *			still reports the route mtu in *params*->mtu_result.
+ *			This flag is only valid for XDP programs; tc programs
+ *			receive -EINVAL since they can redirect to the VLAN
+ *			device directly.
  *
  *		*ctx* is either **struct xdp_md** for XDP programs or
  *		**struct sk_buff** tc cls_act programs.
@@ -7339,6 +7364,7 @@ enum {
 	BPF_FIB_LOOKUP_TBID    = (1U << 3),
 	BPF_FIB_LOOKUP_SRC     = (1U << 4),
 	BPF_FIB_LOOKUP_MARK    = (1U << 5),
+	BPF_FIB_LOOKUP_VLAN    = (1U << 6),
 };
 
 enum {
@@ -7352,6 +7378,7 @@ enum {
 	BPF_FIB_LKUP_RET_NO_NEIGH,     /* no neighbor entry for nh */
 	BPF_FIB_LKUP_RET_FRAG_NEEDED,  /* fragmentation required to fwd */
 	BPF_FIB_LKUP_RET_NO_SRC_ADDR,  /* failed to derive IP src addr */
+	BPF_FIB_LKUP_RET_VLAN_FAILURE, /* VLAN egress, parent unresolvable */
 };
 
 struct bpf_fib_lookup {
@@ -7405,7 +7432,11 @@ struct bpf_fib_lookup {
 
 	union {
 		struct {
-			/* output */
+			/*
+			 * output with BPF_FIB_LOOKUP_VLAN: set from the
+			 * resolved egress VLAN device (see the flag); zeroed
+			 * on other successful lookups.
+			 */
 			__be16	h_vlan_proto;
 			__be16	h_vlan_TCI;
 		};