diff options
Diffstat (limited to 'include/net/xdp.h')
| -rw-r--r-- | include/net/xdp.h | 412 |
1 files changed, 412 insertions, 0 deletions
diff --git a/include/net/xdp.h b/include/net/xdp.h new file mode 100644 index 000000000..55dbc68bf --- /dev/null +++ b/include/net/xdp.h @@ -0,0 +1,412 @@ +/* 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 carries 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 are 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 unregister (which + * also applies 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; + unsigned int napi_id; + u32 frag_size; +} ____cacheline_aligned; /* perf critical, avoid false-sharing */ + +struct xdp_txq_info { + struct net_device *dev; +}; + +enum xdp_buff_flags { + XDP_FLAGS_HAS_FRAGS = BIT(0), /* non-linear xdp buff */ + XDP_FLAGS_FRAGS_PF_MEMALLOC = BIT(1), /* xdp paged memory is under + * pressure + */ +}; + +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*/ + u32 flags; /* supported values defined in xdp_buff_flags */ +}; + +static __always_inline bool xdp_buff_has_frags(struct xdp_buff *xdp) +{ + return !!(xdp->flags & XDP_FLAGS_HAS_FRAGS); +} + +static __always_inline void xdp_buff_set_frags_flag(struct xdp_buff *xdp) +{ + xdp->flags |= XDP_FLAGS_HAS_FRAGS; +} + +static __always_inline void xdp_buff_clear_frags_flag(struct xdp_buff *xdp) +{ + xdp->flags &= ~XDP_FLAGS_HAS_FRAGS; +} + +static __always_inline bool xdp_buff_is_frag_pfmemalloc(struct xdp_buff *xdp) +{ + return !!(xdp->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC); +} + +static __always_inline void xdp_buff_set_frag_pfmemalloc(struct xdp_buff *xdp) +{ + xdp->flags |= XDP_FLAGS_FRAGS_PF_MEMALLOC; +} + +static __always_inline void +xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq) +{ + xdp->frame_sz = frame_sz; + xdp->rxq = rxq; + xdp->flags = 0; +} + +static __always_inline void +xdp_prepare_buff(struct xdp_buff *xdp, unsigned char *hard_start, + int headroom, int data_len, const bool meta_valid) +{ + unsigned char *data = hard_start + headroom; + + xdp->data_hard_start = hard_start; + xdp->data = data; + xdp->data_end = data + data_len; + xdp->data_meta = meta_valid ? data : data + 1; +} + +/* 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); +} + +static __always_inline unsigned int xdp_get_buff_len(struct xdp_buff *xdp) +{ + unsigned int len = xdp->data_end - xdp->data; + struct skb_shared_info *sinfo; + + if (likely(!xdp_buff_has_frags(xdp))) + goto out; + + sinfo = xdp_get_shared_info_from_buff(xdp); + len += sinfo->xdp_frags_size; +out: + return len; +} + +struct xdp_frame { + void *data; + u16 len; + u16 headroom; + u32 metasize; /* uses lower 8-bits */ + /* 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 */ + u32 frame_sz; + u32 flags; /* supported values defined in xdp_buff_flags */ +}; + +static __always_inline bool xdp_frame_has_frags(struct xdp_frame *frame) +{ + return !!(frame->flags & XDP_FLAGS_HAS_FRAGS); +} + +static __always_inline bool xdp_frame_is_frag_pfmemalloc(struct xdp_frame *frame) +{ + return !!(frame->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC); +} + +#define XDP_BULK_QUEUE_SIZE 16 +struct xdp_frame_bulk { + int count; + void *xa; + void *q[XDP_BULK_QUEUE_SIZE]; +}; + +static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq) +{ + /* bq->count will be zero'ed when bq->xa gets updated */ + bq->xa = NULL; +} + +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; +} + +static inline void +xdp_update_skb_shared_info(struct sk_buff *skb, u8 nr_frags, + unsigned int size, unsigned int truesize, + bool pfmemalloc) +{ + skb_shinfo(skb)->nr_frags = nr_frags; + + skb->len += size; + skb->data_len += size; + skb->truesize += truesize; + skb->pfmemalloc |= pfmemalloc; +} + +/* 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); +struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf, + struct sk_buff *skb, + struct net_device *dev); +struct sk_buff *xdp_build_skb_from_frame(struct xdp_frame *xdpf, + struct net_device *dev); +int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp); +struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf); + +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; + xdp->flags = frame->flags; +} + +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; + xdp_frame->flags = xdp->flags; + + 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(void *data, struct xdp_mem_info *mem, bool napi_direct, + struct xdp_buff *xdp); +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); +void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq); +void xdp_return_frame_bulk(struct xdp_frame *xdpf, + struct xdp_frame_bulk *bq); + +/* 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; + struct skb_shared_info *sinfo; + int i; + + /* Curr only page_pool needs this */ + if (mem->type != MEM_TYPE_PAGE_POOL) + return; + + if (likely(!xdp_frame_has_frags(xdpf))) + goto out; + + sinfo = xdp_get_shared_info_from_frame(xdpf); + for (i = 0; i < sinfo->nr_frags; i++) { + struct page *page = skb_frag_page(&sinfo->frags[i]); + + __xdp_release_frame(page_address(page), mem); + } +out: + __xdp_release_frame(xdpf->data, mem); +} + +static __always_inline unsigned int xdp_get_frame_len(struct xdp_frame *xdpf) +{ + struct skb_shared_info *sinfo; + unsigned int len = xdpf->len; + + if (likely(!xdp_frame_has_frags(xdpf))) + goto out; + + sinfo = xdp_get_shared_info_from_frame(xdpf); + len += sinfo->xdp_frags_size; +out: + return len; +} + +int __xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, + struct net_device *dev, u32 queue_index, + unsigned int napi_id, u32 frag_size); +static inline int +xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, + struct net_device *dev, u32 queue_index, + unsigned int napi_id) +{ + return __xdp_rxq_info_reg(xdp_rxq, dev, queue_index, napi_id, 0); +} + +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); +int xdp_reg_mem_model(struct xdp_mem_info *mem, + enum xdp_mem_type type, void *allocator); +void xdp_unreg_mem_model(struct xdp_mem_info *mem); + +/* 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); +} + +static inline bool xdp_metalen_invalid(unsigned long metalen) +{ + return (metalen & (sizeof(__u32) - 1)) || (metalen > 32); +} + +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 XDP_BULK_QUEUE_SIZE + +#endif /* __LINUX_NET_XDP_H__ */ |