[PATCH bpf-next 1/5] netlink: specs: Add XDP RX checksum capability to XDP metadata specs
From: Lorenzo Bianconi <lorenzo@kernel.org>
Date: 2026-02-10 17:22:07
Also in:
bpf, intel-wired-lan, linux-kselftest
Subsystem:
networking drivers, networking [general], the rest, xdp (express data path), yaml netlink (ynl) · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Alexei Starovoitov, Daniel Borkmann, David S. Miller, Jesper Dangaard Brouer, John Fastabend, Donald Hunter
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 <lorenzo@kernel.org> --- Documentation/netlink/specs/netdev.yaml | 5 +++++ include/net/xdp.h | 14 ++++++++++++++ include/uapi/linux/netdev.h | 3 +++ net/core/xdp.c | 29 +++++++++++++++++++++++++++++ tools/include/uapi/linux/netdev.h | 3 +++ 5 files changed, 54 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..9ab9ac10ae2074b70618a9d4f32544d8b9a30b63 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 +647,22 @@ 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, + XDP_CHECKSUM_PARTIAL = CHECKSUM_PARTIAL, +}; + 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..e51346ad3031f28d11c11f8205da6cd954da82de 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c@@ -961,6 +961,35 @@ __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`` + * ``XDP_CHECKSUM_PARTIAL`` + * + * 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`` and + * ``XDP_CHECKSUM_PARTIAL``. + * + * 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, + u8 *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