1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* include/net/xdp.h 3 * 4 * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc. 5 */ 6#ifndef __LINUX_NET_XDP_H__ 7#define __LINUX_NET_XDP_H__ 8 9#include <linux/skbuff.h> /* skb_shared_info */ 10 11/** 12 * DOC: XDP RX-queue information 13 * 14 * The XDP RX-queue info (xdp_rxq_info) is associated with the driver 15 * level RX-ring queues. It is information that is specific to how 16 * the driver have configured a given RX-ring queue. 17 * 18 * Each xdp_buff frame received in the driver carry a (pointer) 19 * reference to this xdp_rxq_info structure. This provides the XDP 20 * data-path read-access to RX-info for both kernel and bpf-side 21 * (limited subset). 22 * 23 * For now, direct access is only safe while running in NAPI/softirq 24 * context. Contents is read-mostly and must not be updated during 25 * driver NAPI/softirq poll. 26 * 27 * The driver usage API is a register and unregister API. 28 * 29 * The struct is not directly tied to the XDP prog. A new XDP prog 30 * can be attached as long as it doesn't change the underlying 31 * RX-ring. If the RX-ring does change significantly, the NIC driver 32 * naturally need to stop the RX-ring before purging and reallocating 33 * memory. In that process the driver MUST call unregistor (which 34 * also apply for driver shutdown and unload). The register API is 35 * also mandatory during RX-ring setup. 36 */ 37 38enum xdp_mem_type { 39 MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */ 40 MEM_TYPE_PAGE_ORDER0, /* Orig XDP full page model */ 41 MEM_TYPE_PAGE_POOL, 42 MEM_TYPE_XSK_BUFF_POOL, 43 MEM_TYPE_MAX, 44}; 45 46/* XDP flags for ndo_xdp_xmit */ 47#define XDP_XMIT_FLUSH (1U << 0) /* doorbell signal consumer */ 48#define XDP_XMIT_FLAGS_MASK XDP_XMIT_FLUSH 49 50struct xdp_mem_info { 51 u32 type; /* enum xdp_mem_type, but known size type */ 52 u32 id; 53}; 54 55struct page_pool; 56 57struct xdp_rxq_info { 58 struct net_device *dev; 59 u32 queue_index; 60 u32 reg_state; 61 struct xdp_mem_info mem; 62} ____cacheline_aligned; /* perf critical, avoid false-sharing */ 63 64struct xdp_txq_info { 65 struct net_device *dev; 66}; 67 68struct xdp_buff { 69 void *data; 70 void *data_end; 71 void *data_meta; 72 void *data_hard_start; 73 struct xdp_rxq_info *rxq; 74 struct xdp_txq_info *txq; 75 u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/ 76}; 77 78/* Reserve memory area at end-of data area. 79 * 80 * This macro reserves tailroom in the XDP buffer by limiting the 81 * XDP/BPF data access to data_hard_end. Notice same area (and size) 82 * is used for XDP_PASS, when constructing the SKB via build_skb(). 83 */ 84#define xdp_data_hard_end(xdp) \ 85 ((xdp)->data_hard_start + (xdp)->frame_sz - \ 86 SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) 87 88static inline struct skb_shared_info * 89xdp_get_shared_info_from_buff(struct xdp_buff *xdp) 90{ 91 return (struct skb_shared_info *)xdp_data_hard_end(xdp); 92} 93 94struct xdp_frame { 95 void *data; 96 u16 len; 97 u16 headroom; 98 u32 metasize:8; 99 u32 frame_sz:24; 100 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time, 101 * while mem info is valid on remote CPU. 102 */ 103 struct xdp_mem_info mem; 104 struct net_device *dev_rx; /* used by cpumap */ 105}; 106 107 108static inline struct skb_shared_info * 109xdp_get_shared_info_from_frame(struct xdp_frame *frame) 110{ 111 void *data_hard_start = frame->data - frame->headroom - sizeof(*frame); 112 113 return (struct skb_shared_info *)(data_hard_start + frame->frame_sz - 114 SKB_DATA_ALIGN(sizeof(struct skb_shared_info))); 115} 116 117struct xdp_cpumap_stats { 118 unsigned int redirect; 119 unsigned int pass; 120 unsigned int drop; 121}; 122 123/* Clear kernel pointers in xdp_frame */ 124static inline void xdp_scrub_frame(struct xdp_frame *frame) 125{ 126 frame->data = NULL; 127 frame->dev_rx = NULL; 128} 129 130/* Avoids inlining WARN macro in fast-path */ 131void xdp_warn(const char *msg, const char *func, const int line); 132#define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__) 133 134struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp); 135 136static inline 137void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp) 138{ 139 xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame); 140 xdp->data = frame->data; 141 xdp->data_end = frame->data + frame->len; 142 xdp->data_meta = frame->data - frame->metasize; 143 xdp->frame_sz = frame->frame_sz; 144} 145 146static inline 147int xdp_update_frame_from_buff(struct xdp_buff *xdp, 148 struct xdp_frame *xdp_frame) 149{ 150 int metasize, headroom; 151 152 /* Assure headroom is available for storing info */ 153 headroom = xdp->data - xdp->data_hard_start; 154 metasize = xdp->data - xdp->data_meta; 155 metasize = metasize > 0 ? metasize : 0; 156 if (unlikely((headroom - metasize) < sizeof(*xdp_frame))) 157 return -ENOSPC; 158 159 /* Catch if driver didn't reserve tailroom for skb_shared_info */ 160 if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) { 161 XDP_WARN("Driver BUG: missing reserved tailroom"); 162 return -ENOSPC; 163 } 164 165 xdp_frame->data = xdp->data; 166 xdp_frame->len = xdp->data_end - xdp->data; 167 xdp_frame->headroom = headroom - sizeof(*xdp_frame); 168 xdp_frame->metasize = metasize; 169 xdp_frame->frame_sz = xdp->frame_sz; 170 171 return 0; 172} 173 174/* Convert xdp_buff to xdp_frame */ 175static inline 176struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp) 177{ 178 struct xdp_frame *xdp_frame; 179 180 if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) 181 return xdp_convert_zc_to_xdp_frame(xdp); 182 183 /* Store info in top of packet */ 184 xdp_frame = xdp->data_hard_start; 185 if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0)) 186 return NULL; 187 188 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */ 189 xdp_frame->mem = xdp->rxq->mem; 190 191 return xdp_frame; 192} 193 194void xdp_return_frame(struct xdp_frame *xdpf); 195void xdp_return_frame_rx_napi(struct xdp_frame *xdpf); 196void xdp_return_buff(struct xdp_buff *xdp); 197 198/* When sending xdp_frame into the network stack, then there is no 199 * return point callback, which is needed to release e.g. DMA-mapping 200 * resources with page_pool. Thus, have explicit function to release 201 * frame resources. 202 */ 203void __xdp_release_frame(void *data, struct xdp_mem_info *mem); 204static inline void xdp_release_frame(struct xdp_frame *xdpf) 205{ 206 struct xdp_mem_info *mem = &xdpf->mem; 207 208 /* Curr only page_pool needs this */ 209 if (mem->type == MEM_TYPE_PAGE_POOL) 210 __xdp_release_frame(xdpf->data, mem); 211} 212 213int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, 214 struct net_device *dev, u32 queue_index); 215void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq); 216void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq); 217bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq); 218int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, 219 enum xdp_mem_type type, void *allocator); 220void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq); 221int xdp_reg_mem_model(struct xdp_mem_info *mem, 222 enum xdp_mem_type type, void *allocator); 223void xdp_unreg_mem_model(struct xdp_mem_info *mem); 224 225/* Drivers not supporting XDP metadata can use this helper, which 226 * rejects any room expansion for metadata as a result. 227 */ 228static __always_inline void 229xdp_set_data_meta_invalid(struct xdp_buff *xdp) 230{ 231 xdp->data_meta = xdp->data + 1; 232} 233 234static __always_inline bool 235xdp_data_meta_unsupported(const struct xdp_buff *xdp) 236{ 237 return unlikely(xdp->data_meta > xdp->data); 238} 239 240struct xdp_attachment_info { 241 struct bpf_prog *prog; 242 u32 flags; 243}; 244 245struct netdev_bpf; 246void xdp_attachment_setup(struct xdp_attachment_info *info, 247 struct netdev_bpf *bpf); 248 249#define DEV_MAP_BULK_SIZE 16 250 251#endif /* __LINUX_NET_XDP_H__ */ 252