Add the the capability to load HW RX checsum in eBPF programs

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

drivers/net/ethernet/intel/ice/ice_txrx_lib.c

@@ -78,69 +78,47 @@ ice_rx_hash_to_skb(const struct ice_rx_ring *rx_ring,
 		libeth_rx_pt_set_hash(skb, hash, decoded);
 }
 
-/**
- * ice_rx_gcs - Set generic checksum in skb
- * @skb: skb currently being received and modified
- * @rx_desc: receive descriptor
- */
-static void ice_rx_gcs(struct sk_buff *skb,
-		       const union ice_32b_rx_flex_desc *rx_desc)
-{
-	const struct ice_32b_rx_flex_desc_nic *desc;
-	u16 csum;
-
-	desc = (struct ice_32b_rx_flex_desc_nic *)rx_desc;
-	skb->ip_summed = CHECKSUM_COMPLETE;
-	csum = (__force u16)desc->raw_csum;
-	skb->csum = csum_unfold((__force __sum16)swab16(csum));
-}
-
-/**
- * ice_rx_csum - Indicate in skb if checksum is good
- * @ring: the ring we care about
- * @skb: skb currently being received and modified
- * @rx_desc: the receive descriptor
- * @ptype: the packet type decoded by hardware
- *
- * skb->protocol must be set before this function is called
- */
 static void
-ice_rx_csum(struct ice_rx_ring *ring, struct sk_buff *skb,
-	    union ice_32b_rx_flex_desc *rx_desc, u16 ptype)
+ice_get_rx_csum(const union ice_32b_rx_flex_desc *rx_desc, u16 ptype,
+		struct ice_rx_ring *ring, enum xdp_checksum *ip_summed,
+		u32 *cksum_meta)
 {
-	struct libeth_rx_pt decoded;
+	struct libeth_rx_pt decoded = libie_rx_pt_parse(ptype);
 	u16 rx_status0, rx_status1;
 	bool ipv4, ipv6;
 
-	/* Start with CHECKSUM_NONE and by default csum_level = 0 */
-	skb->ip_summed = CHECKSUM_NONE;
-
-	decoded = libie_rx_pt_parse(ptype);
 	if (!libeth_rx_pt_has_checksum(ring->netdev, decoded))
-		return;
+		goto checksum_none;
 
 	rx_status0 = le16_to_cpu(rx_desc->wb.status_error0);
 	rx_status1 = le16_to_cpu(rx_desc->wb.status_error1);
-
 	if ((ring->flags & ICE_RX_FLAGS_RING_GCS) &&
 	    rx_desc->wb.rxdid == ICE_RXDID_FLEX_NIC &&
 	    (decoded.inner_prot == LIBETH_RX_PT_INNER_TCP ||
 	     decoded.inner_prot == LIBETH_RX_PT_INNER_UDP ||
 	     decoded.inner_prot == LIBETH_RX_PT_INNER_ICMP)) {
-		ice_rx_gcs(skb, rx_desc);
+		const struct ice_32b_rx_flex_desc_nic *desc;
+		__wsum wcsum;
+		u16 csum;
+
+		desc = (struct ice_32b_rx_flex_desc_nic *)rx_desc;
+		*ip_summed = XDP_CHECKSUM_COMPLETE;
+		csum = (__force u16)desc->raw_csum;
+		wcsum = csum_unfold((__force __sum16)swab16(csum));
+		*cksum_meta = (__force u32)wcsum;
 		return;
 	}
 
 	/* check if HW has decoded the packet and checksum */
 	if (!(rx_status0 & BIT(ICE_RX_FLEX_DESC_STATUS0_L3L4P_S)))
-		return;
+		goto checksum_none;
 
 	ipv4 = libeth_rx_pt_get_ip_ver(decoded) == LIBETH_RX_PT_OUTER_IPV4;
 	ipv6 = libeth_rx_pt_get_ip_ver(decoded) == LIBETH_RX_PT_OUTER_IPV6;
 
 	if (ipv4 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_EIPE_S)))) {
 		ring->vsi->back->hw_rx_eipe_error++;
-		return;
+		goto checksum_none;
 	}
 
 	if (ipv4 && (rx_status0 & (BIT(ICE_RX_FLEX_DESC_STATUS0_XSUM_IPE_S))))
@@ -164,14 +142,45 @@ ice_rx_csum(struct ice_rx_ring *ring, struct sk_buff *skb,
 	 * we need to bump the checksum level by 1 to reflect the fact that
 	 * we are indicating we validated the inner checksum.
 	 */
-	if (decoded.tunnel_type >= LIBETH_RX_PT_TUNNEL_IP_GRENAT)
-		skb->csum_level = 1;
-
-	skb->ip_summed = CHECKSUM_UNNECESSARY;
+	*cksum_meta = decoded.tunnel_type >= LIBETH_RX_PT_TUNNEL_IP_GRENAT;
+	*ip_summed = XDP_CHECKSUM_UNNECESSARY;
 	return;
 
 checksum_fail:
 	ring->vsi->back->hw_csum_rx_error++;
+checksum_none:
+	*ip_summed = XDP_CHECKSUM_NONE;
+	*cksum_meta = 0;
+}
+
+/**
+ * ice_rx_csum - Indicate in skb if checksum is good
+ * @ring: the ring we care about
+ * @skb: skb currently being received and modified
+ * @rx_desc: the receive descriptor
+ * @ptype: the packet type decoded by hardware
+ *
+ * skb->protocol must be set before this function is called
+ */
+static void
+ice_rx_csum(struct ice_rx_ring *ring, struct sk_buff *skb,
+	    union ice_32b_rx_flex_desc *rx_desc, u16 ptype)
+{
+	enum xdp_checksum ip_summed;
+	u32 cksum_meta;
+
+	ice_get_rx_csum(rx_desc, ptype, ring, &ip_summed, &cksum_meta);
+	switch (ip_summed) {
+	case XDP_CHECKSUM_UNNECESSARY:
+		skb->csum_level = cksum_meta;
+		break;
+	case XDP_CHECKSUM_COMPLETE:
+		skb->csum = (__force __wsum)cksum_meta;
+		break;
+	default:
+		break;
+	}
+	skb->ip_summed = ip_summed;
 }
 
 /**
@@ -566,6 +575,30 @@ static int ice_xdp_rx_hash(const struct xdp_md *ctx, u32 *hash,
 	return 0;
 }
 
+/**
+ * ice_xdp_rx_checksum - RX checksum XDP hint handler
+ * @ctx: XDP buff pointer
+ * @ip_summed: RX checksum result destination address
+ * @cksum_meta: XDP RX checksum metadata destination address
+ *
+ * Copy RX checksum result (if available) and its metadata to the
+ * destination address.
+ */
+static int ice_xdp_rx_checksum(const struct xdp_md *ctx,
+			       enum xdp_checksum *ip_summed,
+			       u32 *cksum_meta)
+{
+	const struct libeth_xdp_buff *xdp_ext = (void *)ctx;
+	const union ice_32b_rx_flex_desc *rx_desc = xdp_ext->desc;
+	struct ice_rx_ring *ring;
+
+	ring = libeth_xdp_buff_to_rq(xdp_ext, typeof(*ring), xdp_rxq);
+	ice_get_rx_csum(rx_desc, ice_get_ptype(rx_desc), ring, ip_summed,
+			cksum_meta);
+
+	return 0;
+}
+
 /**
  * ice_xdp_rx_vlan_tag - VLAN tag XDP hint handler
  * @ctx: XDP buff pointer
@@ -598,4 +631,5 @@ const struct xdp_metadata_ops ice_xdp_md_ops = {
 	.xmo_rx_timestamp		= ice_xdp_rx_hw_ts,
 	.xmo_rx_hash			= ice_xdp_rx_hash,
 	.xmo_rx_vlan_tag		= ice_xdp_rx_vlan_tag,
+	.xmo_rx_checksum		= ice_xdp_rx_checksum,
 };

drivers/net/veth.c

@@ -1697,6 +1697,35 @@ static int veth_xdp_rx_vlan_tag(const struct xdp_md *ctx, __be16 *vlan_proto,
 	return err;
 }
 
+static int veth_xdp_rx_checksum(const struct xdp_md *ctx,
+				enum xdp_checksum *ip_summed,
+				u32 *cksum_meta)
+{
+	const struct veth_xdp_buff *_ctx = (void *)ctx;
+	const struct sk_buff *skb = _ctx->skb;
+
+	if (!skb)
+		return -ENODATA;
+
+	*ip_summed = skb->ip_summed;
+	switch (skb->ip_summed) {
+	case CHECKSUM_COMPLETE:
+		*ip_summed = XDP_CHECKSUM_COMPLETE;
+		*cksum_meta = skb->csum;
+		break;
+	case CHECKSUM_UNNECESSARY:
+		*ip_summed = XDP_CHECKSUM_UNNECESSARY;
+		*cksum_meta = skb->csum_level;
+		break;
+	default:
+		*ip_summed = XDP_CHECKSUM_NONE;
+		*cksum_meta = 0;
+		break;
+	}
+
+	return 0;
+}
+
 static const struct net_device_ops veth_netdev_ops = {
 	.ndo_init            = veth_dev_init,
 	.ndo_open            = veth_open,
@@ -1722,6 +1751,7 @@ static const struct xdp_metadata_ops veth_xdp_metadata_ops = {
 	.xmo_rx_timestamp		= veth_xdp_rx_timestamp,
 	.xmo_rx_hash			= veth_xdp_rx_hash,
 	.xmo_rx_vlan_tag		= veth_xdp_rx_vlan_tag,
+	.xmo_rx_checksum		= veth_xdp_rx_checksum,
 };
 
 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HW_CSUM | \

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

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,
 };
 
 /**

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)

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,
 };
 
 /**

tools/testing/selftests/bpf/prog_tests/xdp_metadata.c

@@ -310,6 +310,12 @@ static int verify_xsk_metadata(struct xsk *xsk, bool sent_from_af_xdp)
 	if (!ASSERT_NEQ(meta->rx_hash, 0, "rx_hash"))
 		return -1;
 
+	if (!ASSERT_EQ(meta->ip_summed, XDP_CHECKSUM_NONE, "rx_ip_summed"))
+		return -1;
+
+	if (!ASSERT_EQ(meta->cksum_meta, 0, "rx_cksum_meta"))
+		return -1;
+
 	if (!sent_from_af_xdp) {
 		if (!ASSERT_NEQ(meta->rx_hash_type & XDP_RSS_TYPE_L4, 0, "rx_hash_type"))
 			return -1;

tools/testing/selftests/bpf/progs/xdp_hw_metadata.c

@@ -110,6 +110,14 @@ int rx(struct xdp_md *ctx)
 	else
 		meta->hint_valid |= XDP_META_FIELD_VLAN_TAG;
 
+	err = bpf_xdp_metadata_rx_checksum(ctx,
+			(enum xdp_checksum *)&meta->ip_summed,
+			&meta->cksum_meta);
+	if (err)
+		meta->rx_cksum_err = err;
+	else
+		meta->hint_valid |= XDP_META_FIELD_CHECKSUM;
+
 	__sync_add_and_fetch(&pkts_redir, 1);
 	return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);
 }

tools/testing/selftests/bpf/progs/xdp_metadata.c

@@ -98,6 +98,9 @@ int rx(struct xdp_md *ctx)
 	bpf_xdp_metadata_rx_hash(ctx, &meta->rx_hash, &meta->rx_hash_type);
 	bpf_xdp_metadata_rx_vlan_tag(ctx, &meta->rx_vlan_proto,
 				     &meta->rx_vlan_tci);
+	bpf_xdp_metadata_rx_checksum(ctx,
+				     (enum xdp_checksum *)&meta->ip_summed,
+				     &meta->cksum_meta);
 
 	return bpf_redirect_map(&xsk, ctx->rx_queue_index, XDP_PASS);
 }