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Diffstat (limited to 'include/net/xdp.h')
| -rw-r--r-- | include/net/xdp.h | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/include/net/xdp.h b/include/net/xdp.h new file mode 100644 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__ */ |