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-rw-r--r--include/net/xdp.h248
1 files changed, 248 insertions, 0 deletions
diff --git a/include/net/xdp.h b/include/net/xdp.h
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index 000000000..9dab2bc6f
--- /dev/null
+++ b/include/net/xdp.h
@@ -0,0 +1,248 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* include/net/xdp.h
+ *
+ * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
+ */
+#ifndef __LINUX_NET_XDP_H__
+#define __LINUX_NET_XDP_H__
+
+#include <linux/skbuff.h> /* skb_shared_info */
+
+/**
+ * DOC: XDP RX-queue information
+ *
+ * The XDP RX-queue info (xdp_rxq_info) is associated with the driver
+ * level RX-ring queues. It is information that is specific to how
+ * the driver have configured a given RX-ring queue.
+ *
+ * Each xdp_buff frame received in the driver carry a (pointer)
+ * reference to this xdp_rxq_info structure. This provides the XDP
+ * data-path read-access to RX-info for both kernel and bpf-side
+ * (limited subset).
+ *
+ * For now, direct access is only safe while running in NAPI/softirq
+ * context. Contents is read-mostly and must not be updated during
+ * driver NAPI/softirq poll.
+ *
+ * The driver usage API is a register and unregister API.
+ *
+ * The struct is not directly tied to the XDP prog. A new XDP prog
+ * can be attached as long as it doesn't change the underlying
+ * RX-ring. If the RX-ring does change significantly, the NIC driver
+ * naturally need to stop the RX-ring before purging and reallocating
+ * memory. In that process the driver MUST call unregistor (which
+ * also apply for driver shutdown and unload). The register API is
+ * also mandatory during RX-ring setup.
+ */
+
+enum xdp_mem_type {
+ MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */
+ MEM_TYPE_PAGE_ORDER0, /* Orig XDP full page model */
+ MEM_TYPE_PAGE_POOL,
+ MEM_TYPE_XSK_BUFF_POOL,
+ MEM_TYPE_MAX,
+};
+
+/* XDP flags for ndo_xdp_xmit */
+#define XDP_XMIT_FLUSH (1U << 0) /* doorbell signal consumer */
+#define XDP_XMIT_FLAGS_MASK XDP_XMIT_FLUSH
+
+struct xdp_mem_info {
+ u32 type; /* enum xdp_mem_type, but known size type */
+ u32 id;
+};
+
+struct page_pool;
+
+struct xdp_rxq_info {
+ struct net_device *dev;
+ u32 queue_index;
+ u32 reg_state;
+ struct xdp_mem_info mem;
+} ____cacheline_aligned; /* perf critical, avoid false-sharing */
+
+struct xdp_txq_info {
+ struct net_device *dev;
+};
+
+struct xdp_buff {
+ void *data;
+ void *data_end;
+ void *data_meta;
+ void *data_hard_start;
+ struct xdp_rxq_info *rxq;
+ struct xdp_txq_info *txq;
+ u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/
+};
+
+/* Reserve memory area at end-of data area.
+ *
+ * This macro reserves tailroom in the XDP buffer by limiting the
+ * XDP/BPF data access to data_hard_end. Notice same area (and size)
+ * is used for XDP_PASS, when constructing the SKB via build_skb().
+ */
+#define xdp_data_hard_end(xdp) \
+ ((xdp)->data_hard_start + (xdp)->frame_sz - \
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
+
+static inline struct skb_shared_info *
+xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
+{
+ return (struct skb_shared_info *)xdp_data_hard_end(xdp);
+}
+
+struct xdp_frame {
+ void *data;
+ u16 len;
+ u16 headroom;
+ u32 metasize:8;
+ u32 frame_sz:24;
+ /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
+ * while mem info is valid on remote CPU.
+ */
+ struct xdp_mem_info mem;
+ struct net_device *dev_rx; /* used by cpumap */
+};
+
+
+static inline struct skb_shared_info *
+xdp_get_shared_info_from_frame(struct xdp_frame *frame)
+{
+ void *data_hard_start = frame->data - frame->headroom - sizeof(*frame);
+
+ return (struct skb_shared_info *)(data_hard_start + frame->frame_sz -
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
+}
+
+struct xdp_cpumap_stats {
+ unsigned int redirect;
+ unsigned int pass;
+ unsigned int drop;
+};
+
+/* Clear kernel pointers in xdp_frame */
+static inline void xdp_scrub_frame(struct xdp_frame *frame)
+{
+ frame->data = NULL;
+ frame->dev_rx = NULL;
+}
+
+/* Avoids inlining WARN macro in fast-path */
+void xdp_warn(const char *msg, const char *func, const int line);
+#define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__)
+
+struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp);
+
+static inline
+void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp)
+{
+ xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame);
+ xdp->data = frame->data;
+ xdp->data_end = frame->data + frame->len;
+ xdp->data_meta = frame->data - frame->metasize;
+ xdp->frame_sz = frame->frame_sz;
+}
+
+static inline
+int xdp_update_frame_from_buff(struct xdp_buff *xdp,
+ struct xdp_frame *xdp_frame)
+{
+ int metasize, headroom;
+
+ /* Assure headroom is available for storing info */
+ headroom = xdp->data - xdp->data_hard_start;
+ metasize = xdp->data - xdp->data_meta;
+ metasize = metasize > 0 ? metasize : 0;
+ if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
+ return -ENOSPC;
+
+ /* Catch if driver didn't reserve tailroom for skb_shared_info */
+ if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) {
+ XDP_WARN("Driver BUG: missing reserved tailroom");
+ return -ENOSPC;
+ }
+
+ xdp_frame->data = xdp->data;
+ xdp_frame->len = xdp->data_end - xdp->data;
+ xdp_frame->headroom = headroom - sizeof(*xdp_frame);
+ xdp_frame->metasize = metasize;
+ xdp_frame->frame_sz = xdp->frame_sz;
+
+ return 0;
+}
+
+/* Convert xdp_buff to xdp_frame */
+static inline
+struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
+{
+ struct xdp_frame *xdp_frame;
+
+ if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL)
+ return xdp_convert_zc_to_xdp_frame(xdp);
+
+ /* Store info in top of packet */
+ xdp_frame = xdp->data_hard_start;
+ if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0))
+ return NULL;
+
+ /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
+ xdp_frame->mem = xdp->rxq->mem;
+
+ return xdp_frame;
+}
+
+void xdp_return_frame(struct xdp_frame *xdpf);
+void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
+void xdp_return_buff(struct xdp_buff *xdp);
+
+/* When sending xdp_frame into the network stack, then there is no
+ * return point callback, which is needed to release e.g. DMA-mapping
+ * resources with page_pool. Thus, have explicit function to release
+ * frame resources.
+ */
+void __xdp_release_frame(void *data, struct xdp_mem_info *mem);
+static inline void xdp_release_frame(struct xdp_frame *xdpf)
+{
+ struct xdp_mem_info *mem = &xdpf->mem;
+
+ /* Curr only page_pool needs this */
+ if (mem->type == MEM_TYPE_PAGE_POOL)
+ __xdp_release_frame(xdpf->data, mem);
+}
+
+int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
+ struct net_device *dev, u32 queue_index);
+void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
+void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);
+bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
+int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
+ enum xdp_mem_type type, void *allocator);
+void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq);
+
+/* Drivers not supporting XDP metadata can use this helper, which
+ * rejects any room expansion for metadata as a result.
+ */
+static __always_inline void
+xdp_set_data_meta_invalid(struct xdp_buff *xdp)
+{
+ xdp->data_meta = xdp->data + 1;
+}
+
+static __always_inline bool
+xdp_data_meta_unsupported(const struct xdp_buff *xdp)
+{
+ return unlikely(xdp->data_meta > xdp->data);
+}
+
+struct xdp_attachment_info {
+ struct bpf_prog *prog;
+ u32 flags;
+};
+
+struct netdev_bpf;
+void xdp_attachment_setup(struct xdp_attachment_info *info,
+ struct netdev_bpf *bpf);
+
+#define DEV_MAP_BULK_SIZE 16
+
+#endif /* __LINUX_NET_XDP_H__ */