Implement functionality that enables drivers to expose VLAN tag
to XDP code.
VLAN tag is represented by 2 variables:
- protocol ID, which is passed to bpf code in BE
- VLAN TCI, in host byte order
Acked-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
Signed-off-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx>
---
Documentation/networking/xdp-rx-metadata.rst | 8 ++++-
include/net/xdp.h | 6 ++++
include/uapi/linux/netdev.h | 5 ++-
net/core/xdp.c | 33 ++++++++++++++++++++
tools/include/uapi/linux/netdev.h | 5 ++-
5 files changed, 54 insertions(+), 3 deletions(-)
diff --git a/Documentation/networking/xdp-rx-metadata.rst b/Documentation/networking/xdp-rx-metadata.rst
index 205696780b78..bb53b00d1b2c 100644
--- a/Documentation/networking/xdp-rx-metadata.rst
+++ b/Documentation/networking/xdp-rx-metadata.rst
@@ -18,7 +18,13 @@ 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_vlan_tag
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/net/xdp.h b/include/net/xdp.h
index eb77040b4825..ef79f124dbcf 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -399,6 +399,10 @@ void xdp_attachment_setup(struct xdp_attachment_info *info,
NETDEV_XDP_RX_METADATA_HASH, \
bpf_xdp_metadata_rx_hash, \
xmo_rx_hash) \
+ XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_VLAN_TAG, \
+ NETDEV_XDP_RX_METADATA_VLAN_TAG, \
+ bpf_xdp_metadata_rx_vlan_tag, \
+ xmo_rx_vlan_tag) \
enum xdp_rx_metadata {
#define XDP_METADATA_KFUNC(name, _, __, ___) name,
@@ -460,6 +464,8 @@ 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_vlan_tag)(const struct xdp_md *ctx, __be16 *vlan_proto,
+ u16 *vlan_tci);
};
#ifdef CONFIG_NET
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index 2943a151d4f1..661f603e3e43 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -44,13 +44,16 @@ enum netdev_xdp_act {
* timestamp via bpf_xdp_metadata_rx_timestamp().
* @NETDEV_XDP_RX_METADATA_HASH: Device is capable of exposing receive packet
* hash via bpf_xdp_metadata_rx_hash().
+ * @NETDEV_XDP_RX_METADATA_VLAN_TAG: Device is capable of exposing stripped
+ * receive VLAN tag (proto and TCI) via bpf_xdp_metadata_rx_vlan_tag().
*/
enum netdev_xdp_rx_metadata {
NETDEV_XDP_RX_METADATA_TIMESTAMP = 1,
NETDEV_XDP_RX_METADATA_HASH = 2,
+ NETDEV_XDP_RX_METADATA_VLAN_TAG = 4,
/* private: */
- NETDEV_XDP_RX_METADATA_MASK = 3,
+ NETDEV_XDP_RX_METADATA_MASK = 7,
};
enum {
diff --git a/net/core/xdp.c b/net/core/xdp.c
index df4789ab512d..fb87925b3dc3 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -738,6 +738,39 @@ __bpf_kfunc int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash,
return -EOPNOTSUPP;
}
+/**
+ * bpf_xdp_metadata_rx_vlan_tag - Get XDP packet outermost VLAN tag
+ * @ctx: XDP context pointer.
+ * @vlan_proto: Destination pointer for VLAN Tag protocol identifier (TPID).
+ * @vlan_tci: Destination pointer for VLAN TCI (VID + DEI + PCP)
+ *
+ * In case of success, ``vlan_proto`` contains *Tag protocol identifier (TPID)*,
+ * usually ``ETH_P_8021Q`` or ``ETH_P_8021AD``, but some networks can use
+ * custom TPIDs. ``vlan_proto`` is stored in **network byte order (BE)**
+ * and should be used as follows:
+ * ``if (vlan_proto == bpf_htons(ETH_P_8021Q)) do_something();``
+ *
+ * ``vlan_tci`` contains the remaining 16 bits of a VLAN tag.
+ * Driver is expected to provide those in **host byte order (usually LE)**,
+ * so the bpf program should not perform byte conversion.
+ * According to 802.1Q standard, *VLAN TCI (Tag control information)*
+ * is a bit field that contains:
+ * *VLAN identifier (VID)* that can be read with ``vlan_tci & 0xfff``,
+ * *Drop eligible indicator (DEI)* - 1 bit,
+ * *Priority code point (PCP)* - 3 bits.
+ * For detailed meaning of DEI and PCP, please refer to other sources.
+ *
+ * Return:
+ * * Returns 0 on success or ``-errno`` on error.
+ * * ``-EOPNOTSUPP`` : device driver doesn't implement kfunc
+ * * ``-ENODATA`` : VLAN tag was not stripped or is not available
+ */
+__bpf_kfunc int bpf_xdp_metadata_rx_vlan_tag(const struct xdp_md *ctx,
+ __be16 *vlan_proto, u16 *vlan_tci)
+{
+ return -EOPNOTSUPP;
+}
+
__diag_pop();
BTF_SET8_START(xdp_metadata_kfunc_ids)
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index 2943a151d4f1..661f603e3e43 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -44,13 +44,16 @@ enum netdev_xdp_act {
* timestamp via bpf_xdp_metadata_rx_timestamp().
* @NETDEV_XDP_RX_METADATA_HASH: Device is capable of exposing receive packet
* hash via bpf_xdp_metadata_rx_hash().
+ * @NETDEV_XDP_RX_METADATA_VLAN_TAG: Device is capable of exposing stripped
+ * receive VLAN tag (proto and TCI) via bpf_xdp_metadata_rx_vlan_tag().
*/
enum netdev_xdp_rx_metadata {
NETDEV_XDP_RX_METADATA_TIMESTAMP = 1,
NETDEV_XDP_RX_METADATA_HASH = 2,
+ NETDEV_XDP_RX_METADATA_VLAN_TAG = 4,
/* private: */
- NETDEV_XDP_RX_METADATA_MASK = 3,
+ NETDEV_XDP_RX_METADATA_MASK = 7,
};
enum {
--
2.41.0
