Introduce XDP RX checksum capability to XDP metadata specs. XDP RX
checksum will be use by devices capable of exposing receive checksum
result via bpf_xdp_metadata_rx_checksum().
Moreover, introduce xmo_rx_checksum netdev callback in order allow the
eBPF program bounded to the device to retrieve the RX checksum result
computed by the hw NIC.

Signed-off-by: Lorenzo Bianconi <[email protected]>
---
 Documentation/netlink/specs/netdev.yaml |  5 +++++
 include/net/xdp.h                       | 13 +++++++++++++
 include/uapi/linux/netdev.h             |  3 +++
 net/core/xdp.c                          | 28 ++++++++++++++++++++++++++++
 tools/include/uapi/linux/netdev.h       |  3 +++
 5 files changed, 52 insertions(+)

diff --git a/Documentation/netlink/specs/netdev.yaml 
b/Documentation/netlink/specs/netdev.yaml
index 
596c306ce52b8303b20680ff0cd34d4fd9db0e48..58eda634668a07860447a65d9fc2284839af6244
 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -61,6 +61,11 @@ definitions:
         doc: |
           Device is capable of exposing receive packet VLAN tag via
           bpf_xdp_metadata_rx_vlan_tag().
+      -
+        name: checksum
+        doc: |
+          Device is capable of exposing receive checksum result via
+          bpf_xdp_metadata_rx_checksum().
   -
     type: flags
     name: xsk-flags
diff --git a/include/net/xdp.h b/include/net/xdp.h
index 
aa742f413c358575396530879af4570dc3fc18de..00abb2e1e85514b4080d0e4e6e3b8f5f67f73b61
 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h
@@ -586,6 +586,10 @@ void xdp_attachment_setup(struct xdp_attachment_info *info,
                           NETDEV_XDP_RX_METADATA_VLAN_TAG, \
                           bpf_xdp_metadata_rx_vlan_tag, \
                           xmo_rx_vlan_tag) \
+       XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_CHECKSUM, \
+                          NETDEV_XDP_RX_METADATA_CHECKSUM, \
+                          bpf_xdp_metadata_rx_checksum, \
+                          xmo_rx_checksum)
 
 enum xdp_rx_metadata {
 #define XDP_METADATA_KFUNC(name, _, __, ___) name,
@@ -643,12 +647,21 @@ enum xdp_rss_hash_type {
        XDP_RSS_TYPE_L4_IPV6_SCTP_EX = XDP_RSS_TYPE_L4_IPV6_SCTP | 
XDP_RSS_L3_DYNHDR,
 };
 
+enum xdp_checksum {
+       XDP_CHECKSUM_NONE               = CHECKSUM_NONE,
+       XDP_CHECKSUM_UNNECESSARY        = CHECKSUM_UNNECESSARY,
+       XDP_CHECKSUM_COMPLETE           = CHECKSUM_COMPLETE,
+};
+
 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);
+       int     (*xmo_rx_checksum)(const struct xdp_md *ctx,
+                                  enum xdp_checksum *ip_summed,
+                                  u32 *cksum_meta);
 };
 
 #ifdef CONFIG_NET
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index 
e0b579a1df4f2126acec6c44c299e97bbbefe640..d20da430cfd57bc26b5ea2f406c27b48d8a81693
 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -47,11 +47,14 @@ enum netdev_xdp_act {
  *   hash via bpf_xdp_metadata_rx_hash().
  * @NETDEV_XDP_RX_METADATA_VLAN_TAG: Device is capable of exposing receive
  *   packet VLAN tag via bpf_xdp_metadata_rx_vlan_tag().
+ * @NETDEV_XDP_RX_METADATA_CHECKSUM: Device is capable of exposing receive
+ *   checksum result via bpf_xdp_metadata_rx_checksum().
  */
 enum netdev_xdp_rx_metadata {
        NETDEV_XDP_RX_METADATA_TIMESTAMP = 1,
        NETDEV_XDP_RX_METADATA_HASH = 2,
        NETDEV_XDP_RX_METADATA_VLAN_TAG = 4,
+       NETDEV_XDP_RX_METADATA_CHECKSUM = 8,
 };
 
 /**
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 
fee6d080ee85fc2d278bfdddfd1365633058ec06..06d3c2333fa4aacd1b9343471efb0d3150838de5
 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -961,6 +961,34 @@ __bpf_kfunc int bpf_xdp_metadata_rx_vlan_tag(const struct 
xdp_md *ctx,
        return -EOPNOTSUPP;
 }
 
+/**
+ * bpf_xdp_metadata_rx_checksum - Read XDP frame RX checksum.
+ * @ctx: XDP context pointer.
+ * @ip_summed: Return value pointer indicating checksum result.
+ * @cksum_meta: Return value pointer indicating checksum result metadata.
+ *
+ * In case of success, ``ip_summed`` is set to the RX checksum result. Possible
+ * values are:
+ * ``XDP_CHECKSUM_NONE``
+ * ``XDP_CHECKSUM_UNNECESSARY``
+ * ``XDP_CHECKSUM_COMPLETE``
+ *
+ * In case of success, ``cksum_meta`` contains the hw computed checksum value
+ * for ``XDP_CHECKSUM_COMPLETE`` or the ``csum_level`` for
+ * ``XDP_CHECKSUM_UNNECESSARY``. It is set to 0 for ``XDP_CHECKSUM_NONE``
+ *
+ * Return:
+ * * Returns 0 on success or ``-errno`` on error.
+ * * ``-EOPNOTSUPP`` : means device driver does not implement kfunc
+ * * ``-ENODATA``    : means no RX-timestamp available for this frame
+ */
+__bpf_kfunc int bpf_xdp_metadata_rx_checksum(const struct xdp_md *ctx,
+                                            enum xdp_checksum *ip_summed,
+                                            u32 *cksum_meta)
+{
+       return -EOPNOTSUPP;
+}
+
 __bpf_kfunc_end_defs();
 
 BTF_KFUNCS_START(xdp_metadata_kfunc_ids)
diff --git a/tools/include/uapi/linux/netdev.h 
b/tools/include/uapi/linux/netdev.h
index 
e0b579a1df4f2126acec6c44c299e97bbbefe640..d20da430cfd57bc26b5ea2f406c27b48d8a81693
 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -47,11 +47,14 @@ enum netdev_xdp_act {
  *   hash via bpf_xdp_metadata_rx_hash().
  * @NETDEV_XDP_RX_METADATA_VLAN_TAG: Device is capable of exposing receive
  *   packet VLAN tag via bpf_xdp_metadata_rx_vlan_tag().
+ * @NETDEV_XDP_RX_METADATA_CHECKSUM: Device is capable of exposing receive
+ *   checksum result via bpf_xdp_metadata_rx_checksum().
  */
 enum netdev_xdp_rx_metadata {
        NETDEV_XDP_RX_METADATA_TIMESTAMP = 1,
        NETDEV_XDP_RX_METADATA_HASH = 2,
        NETDEV_XDP_RX_METADATA_VLAN_TAG = 4,
+       NETDEV_XDP_RX_METADATA_CHECKSUM = 8,
 };
 
 /**

-- 
2.53.0


Reply via email to