[PATCH 09/15] xdp: Add VLAN tag hint

[Larysa Zaremba]

Implement functionality that enables drivers to expose VLAN tag
to XDP code.

Signed-off-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx>
---
 Documentation/networking/xdp-rx-metadata.rst | 11 ++++++++-
 include/linux/netdevice.h                    |  2 ++
 include/net/xdp.h                            |  4 ++++
 kernel/bpf/offload.c                         |  4 ++++
 net/core/xdp.c                               | 24 ++++++++++++++++++++
 5 files changed, 44 insertions(+), 1 deletion(-)

diff --git a/Documentation/networking/xdp-rx-metadata.rst b/Documentation/networking/xdp-rx-metadata.rst
index 25ce72af81c2..73a78029c596 100644
--- a/Documentation/networking/xdp-rx-metadata.rst
+++ b/Documentation/networking/xdp-rx-metadata.rst
@@ -18,7 +18,16 @@ Currently, the following kfuncs are supported. In the future, as more
 metadata is supported, this set will grow:
 
 .. kernel-doc:: net/core/xdp.c
-   :identifiers: bpf_xdp_metadata_rx_timestamp bpf_xdp_metadata_rx_hash
+   :identifiers: bpf_xdp_metadata_rx_timestamp
+
+.. kernel-doc:: net/core/xdp.c
+   :identifiers: bpf_xdp_metadata_rx_hash
+
+.. kernel-doc:: net/core/xdp.c
+   :identifiers: bpf_xdp_metadata_rx_ctag
+
+.. kernel-doc:: net/core/xdp.c
+   :identifiers: bpf_xdp_metadata_rx_stag
 
 An XDP program can use these kfuncs to read the metadata into stack
 variables for its own consumption. Or, to pass the metadata on to other
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 08fbd4622ccf..fdae37fe11f5 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1655,6 +1655,8 @@ struct xdp_metadata_ops {
 	int	(*xmo_rx_timestamp)(const struct xdp_md *ctx, u64 *timestamp);
 	int	(*xmo_rx_hash)(const struct xdp_md *ctx, u32 *hash,
 			       enum xdp_rss_hash_type *rss_type);
+	int	(*xmo_rx_ctag)(const struct xdp_md *ctx, u16 *vlan_tag);
+	int	(*xmo_rx_stag)(const struct xdp_md *ctx, u16 *vlan_tag);
 };
 
 /**
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 6381560efae2..2db7439fc60f 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -389,6 +389,10 @@ void xdp_attachment_setup(struct xdp_attachment_info *info,
 			   bpf_xdp_metadata_rx_timestamp) \
 	XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_HASH, \
 			   bpf_xdp_metadata_rx_hash) \
+	XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_CTAG, \
+			   bpf_xdp_metadata_rx_ctag) \
+	XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_STAG, \
+			   bpf_xdp_metadata_rx_stag) \
 
 enum {
 #define XDP_METADATA_KFUNC(name, _) name,
diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
index d9c9f45e3529..2c6b6e82cfac 100644
--- a/kernel/bpf/offload.c
+++ b/kernel/bpf/offload.c
@@ -848,6 +848,10 @@ void *bpf_dev_bound_resolve_kfunc(struct bpf_prog *prog, u32 func_id)
 		p = ops->xmo_rx_timestamp;
 	else if (func_id == bpf_xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_RX_HASH))
 		p = ops->xmo_rx_hash;
+	else if (func_id == bpf_xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_RX_CTAG))
+		p = ops->xmo_rx_ctag;
+	else if (func_id == bpf_xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_RX_STAG))
+		p = ops->xmo_rx_stag;
 out:
 	up_read(&bpf_devs_lock);
 
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 41e5ca8643ec..eff21501609f 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -738,6 +738,30 @@ __bpf_kfunc int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash,
 	return -EOPNOTSUPP;
 }
 
+/**
+ * bpf_xdp_metadata_rx_ctag - Read XDP packet inner vlan tag.
+ * @ctx: XDP context pointer.
+ * @vlan_tag: Return value pointer.
+ *
+ * Returns 0 on success or ``-errno`` on error.
+ */
+__bpf_kfunc int bpf_xdp_metadata_rx_ctag(const struct xdp_md *ctx, u16 *vlan_tag)
+{
+	return -EOPNOTSUPP;
+}
+
+/**
+ * bpf_xdp_metadata_rx_stag - Read XDP packet outer vlan tag.
+ * @ctx: XDP context pointer.
+ * @vlan_tag: Return value pointer.
+ *
+ * Returns 0 on success or ``-errno`` on error.
+ */
+__bpf_kfunc int bpf_xdp_metadata_rx_stag(const struct xdp_md *ctx, u16 *vlan_tag)
+{
+	return -EOPNOTSUPP;
+}
+
 __diag_pop();
 
 BTF_SET8_START(xdp_metadata_kfunc_ids)
-- 
2.35.3