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 38 enum 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 50 struct xdp_mem_info { 51 u32 type; /* enum xdp_mem_type, but known size type */ 52 u32 id; 53 }; 54 55 struct page_pool; 56 57 struct xdp_rxq_info { 58 struct net_device *dev; 59 u32 queue_index; 60 u32 reg_state; 61 struct xdp_mem_info mem; 62 unsigned int napi_id; 63 } ____cacheline_aligned; /* perf critical, avoid false-sharing */ 64 65 struct xdp_txq_info { 66 struct net_device *dev; 67 }; 68 69 struct xdp_buff { 70 void *data; 71 void *data_end; 72 void *data_meta; 73 void *data_hard_start; 74 struct xdp_rxq_info *rxq; 75 struct xdp_txq_info *txq; 76 u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/ 77 }; 78 79 static __always_inline void 80 xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq) 81 { 82 xdp->frame_sz = frame_sz; 83 xdp->rxq = rxq; 84 } 85 86 static __always_inline void 87 xdp_prepare_buff(struct xdp_buff *xdp, unsigned char *hard_start, 88 int headroom, int data_len, const bool meta_valid) 89 { 90 unsigned char *data = hard_start + headroom; 91 92 xdp->data_hard_start = hard_start; 93 xdp->data = data; 94 xdp->data_end = data + data_len; 95 xdp->data_meta = meta_valid ? data : data + 1; 96 } 97 98 /* Reserve memory area at end-of data area. 99 * 100 * This macro reserves tailroom in the XDP buffer by limiting the 101 * XDP/BPF data access to data_hard_end. Notice same area (and size) 102 * is used for XDP_PASS, when constructing the SKB via build_skb(). 103 */ 104 #define xdp_data_hard_end(xdp) \ 105 ((xdp)->data_hard_start + (xdp)->frame_sz - \ 106 SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) 107 108 static inline struct skb_shared_info * 109 xdp_get_shared_info_from_buff(struct xdp_buff *xdp) 110 { 111 return (struct skb_shared_info *)xdp_data_hard_end(xdp); 112 } 113 114 struct xdp_frame { 115 void *data; 116 u16 len; 117 u16 headroom; 118 u32 metasize:8; 119 u32 frame_sz:24; 120 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time, 121 * while mem info is valid on remote CPU. 122 */ 123 struct xdp_mem_info mem; 124 struct net_device *dev_rx; /* used by cpumap */ 125 }; 126 127 #define XDP_BULK_QUEUE_SIZE 16 128 struct xdp_frame_bulk { 129 int count; 130 void *xa; 131 void *q[XDP_BULK_QUEUE_SIZE]; 132 }; 133 134 static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq) 135 { 136 /* bq->count will be zero'ed when bq->xa gets updated */ 137 bq->xa = NULL; 138 } 139 140 static inline struct skb_shared_info * 141 xdp_get_shared_info_from_frame(struct xdp_frame *frame) 142 { 143 void *data_hard_start = frame->data - frame->headroom - sizeof(*frame); 144 145 return (struct skb_shared_info *)(data_hard_start + frame->frame_sz - 146 SKB_DATA_ALIGN(sizeof(struct skb_shared_info))); 147 } 148 149 struct xdp_cpumap_stats { 150 unsigned int redirect; 151 unsigned int pass; 152 unsigned int drop; 153 }; 154 155 /* Clear kernel pointers in xdp_frame */ 156 static inline void xdp_scrub_frame(struct xdp_frame *frame) 157 { 158 frame->data = NULL; 159 frame->dev_rx = NULL; 160 } 161 162 /* Avoids inlining WARN macro in fast-path */ 163 void xdp_warn(const char *msg, const char *func, const int line); 164 #define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__) 165 166 struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp); 167 struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf, 168 struct sk_buff *skb, 169 struct net_device *dev); 170 struct sk_buff *xdp_build_skb_from_frame(struct xdp_frame *xdpf, 171 struct net_device *dev); 172 int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp); 173 174 static inline 175 void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp) 176 { 177 xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame); 178 xdp->data = frame->data; 179 xdp->data_end = frame->data + frame->len; 180 xdp->data_meta = frame->data - frame->metasize; 181 xdp->frame_sz = frame->frame_sz; 182 } 183 184 static inline 185 int xdp_update_frame_from_buff(struct xdp_buff *xdp, 186 struct xdp_frame *xdp_frame) 187 { 188 int metasize, headroom; 189 190 /* Assure headroom is available for storing info */ 191 headroom = xdp->data - xdp->data_hard_start; 192 metasize = xdp->data - xdp->data_meta; 193 metasize = metasize > 0 ? metasize : 0; 194 if (unlikely((headroom - metasize) < sizeof(*xdp_frame))) 195 return -ENOSPC; 196 197 /* Catch if driver didn't reserve tailroom for skb_shared_info */ 198 if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) { 199 XDP_WARN("Driver BUG: missing reserved tailroom"); 200 return -ENOSPC; 201 } 202 203 xdp_frame->data = xdp->data; 204 xdp_frame->len = xdp->data_end - xdp->data; 205 xdp_frame->headroom = headroom - sizeof(*xdp_frame); 206 xdp_frame->metasize = metasize; 207 xdp_frame->frame_sz = xdp->frame_sz; 208 209 return 0; 210 } 211 212 /* Convert xdp_buff to xdp_frame */ 213 static inline 214 struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp) 215 { 216 struct xdp_frame *xdp_frame; 217 218 if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) 219 return xdp_convert_zc_to_xdp_frame(xdp); 220 221 /* Store info in top of packet */ 222 xdp_frame = xdp->data_hard_start; 223 if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0)) 224 return NULL; 225 226 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */ 227 xdp_frame->mem = xdp->rxq->mem; 228 229 return xdp_frame; 230 } 231 232 void xdp_return_frame(struct xdp_frame *xdpf); 233 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf); 234 void xdp_return_buff(struct xdp_buff *xdp); 235 void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq); 236 void xdp_return_frame_bulk(struct xdp_frame *xdpf, 237 struct xdp_frame_bulk *bq); 238 239 /* When sending xdp_frame into the network stack, then there is no 240 * return point callback, which is needed to release e.g. DMA-mapping 241 * resources with page_pool. Thus, have explicit function to release 242 * frame resources. 243 */ 244 void __xdp_release_frame(void *data, struct xdp_mem_info *mem); 245 static inline void xdp_release_frame(struct xdp_frame *xdpf) 246 { 247 struct xdp_mem_info *mem = &xdpf->mem; 248 249 /* Curr only page_pool needs this */ 250 if (mem->type == MEM_TYPE_PAGE_POOL) 251 __xdp_release_frame(xdpf->data, mem); 252 } 253 254 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, 255 struct net_device *dev, u32 queue_index, unsigned int napi_id); 256 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq); 257 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq); 258 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq); 259 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, 260 enum xdp_mem_type type, void *allocator); 261 void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq); 262 263 /* Drivers not supporting XDP metadata can use this helper, which 264 * rejects any room expansion for metadata as a result. 265 */ 266 static __always_inline void 267 xdp_set_data_meta_invalid(struct xdp_buff *xdp) 268 { 269 xdp->data_meta = xdp->data + 1; 270 } 271 272 static __always_inline bool 273 xdp_data_meta_unsupported(const struct xdp_buff *xdp) 274 { 275 return unlikely(xdp->data_meta > xdp->data); 276 } 277 278 struct xdp_attachment_info { 279 struct bpf_prog *prog; 280 u32 flags; 281 }; 282 283 struct netdev_bpf; 284 void xdp_attachment_setup(struct xdp_attachment_info *info, 285 struct netdev_bpf *bpf); 286 287 #define DEV_MAP_BULK_SIZE XDP_BULK_QUEUE_SIZE 288 289 #endif /* __LINUX_NET_XDP_H__ */ 290