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 #include <uapi/linux/netdev.h> 11 12 /** 13 * DOC: XDP RX-queue information 14 * 15 * The XDP RX-queue info (xdp_rxq_info) is associated with the driver 16 * level RX-ring queues. It is information that is specific to how 17 * the driver have configured a given RX-ring queue. 18 * 19 * Each xdp_buff frame received in the driver carries a (pointer) 20 * reference to this xdp_rxq_info structure. This provides the XDP 21 * data-path read-access to RX-info for both kernel and bpf-side 22 * (limited subset). 23 * 24 * For now, direct access is only safe while running in NAPI/softirq 25 * context. Contents are read-mostly and must not be updated during 26 * driver NAPI/softirq poll. 27 * 28 * The driver usage API is a register and unregister API. 29 * 30 * The struct is not directly tied to the XDP prog. A new XDP prog 31 * can be attached as long as it doesn't change the underlying 32 * RX-ring. If the RX-ring does change significantly, the NIC driver 33 * naturally need to stop the RX-ring before purging and reallocating 34 * memory. In that process the driver MUST call unregister (which 35 * also applies for driver shutdown and unload). The register API is 36 * also mandatory during RX-ring setup. 37 */ 38 39 enum xdp_mem_type { 40 MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */ 41 MEM_TYPE_PAGE_ORDER0, /* Orig XDP full page model */ 42 MEM_TYPE_PAGE_POOL, 43 MEM_TYPE_XSK_BUFF_POOL, 44 MEM_TYPE_MAX, 45 }; 46 47 typedef u32 xdp_features_t; 48 49 /* XDP flags for ndo_xdp_xmit */ 50 #define XDP_XMIT_FLUSH (1U << 0) /* doorbell signal consumer */ 51 #define XDP_XMIT_FLAGS_MASK XDP_XMIT_FLUSH 52 53 struct xdp_mem_info { 54 u32 type; /* enum xdp_mem_type, but known size type */ 55 u32 id; 56 }; 57 58 struct page_pool; 59 60 struct xdp_rxq_info { 61 struct net_device *dev; 62 u32 queue_index; 63 u32 reg_state; 64 struct xdp_mem_info mem; 65 unsigned int napi_id; 66 u32 frag_size; 67 } ____cacheline_aligned; /* perf critical, avoid false-sharing */ 68 69 struct xdp_txq_info { 70 struct net_device *dev; 71 }; 72 73 enum xdp_buff_flags { 74 XDP_FLAGS_HAS_FRAGS = BIT(0), /* non-linear xdp buff */ 75 XDP_FLAGS_FRAGS_PF_MEMALLOC = BIT(1), /* xdp paged memory is under 76 * pressure 77 */ 78 }; 79 80 struct xdp_buff { 81 void *data; 82 void *data_end; 83 void *data_meta; 84 void *data_hard_start; 85 struct xdp_rxq_info *rxq; 86 struct xdp_txq_info *txq; 87 u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/ 88 u32 flags; /* supported values defined in xdp_buff_flags */ 89 }; 90 91 static __always_inline bool xdp_buff_has_frags(struct xdp_buff *xdp) 92 { 93 return !!(xdp->flags & XDP_FLAGS_HAS_FRAGS); 94 } 95 96 static __always_inline void xdp_buff_set_frags_flag(struct xdp_buff *xdp) 97 { 98 xdp->flags |= XDP_FLAGS_HAS_FRAGS; 99 } 100 101 static __always_inline void xdp_buff_clear_frags_flag(struct xdp_buff *xdp) 102 { 103 xdp->flags &= ~XDP_FLAGS_HAS_FRAGS; 104 } 105 106 static __always_inline bool xdp_buff_is_frag_pfmemalloc(struct xdp_buff *xdp) 107 { 108 return !!(xdp->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC); 109 } 110 111 static __always_inline void xdp_buff_set_frag_pfmemalloc(struct xdp_buff *xdp) 112 { 113 xdp->flags |= XDP_FLAGS_FRAGS_PF_MEMALLOC; 114 } 115 116 static __always_inline void 117 xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq) 118 { 119 xdp->frame_sz = frame_sz; 120 xdp->rxq = rxq; 121 xdp->flags = 0; 122 } 123 124 static __always_inline void 125 xdp_prepare_buff(struct xdp_buff *xdp, unsigned char *hard_start, 126 int headroom, int data_len, const bool meta_valid) 127 { 128 unsigned char *data = hard_start + headroom; 129 130 xdp->data_hard_start = hard_start; 131 xdp->data = data; 132 xdp->data_end = data + data_len; 133 xdp->data_meta = meta_valid ? data : data + 1; 134 } 135 136 /* Reserve memory area at end-of data area. 137 * 138 * This macro reserves tailroom in the XDP buffer by limiting the 139 * XDP/BPF data access to data_hard_end. Notice same area (and size) 140 * is used for XDP_PASS, when constructing the SKB via build_skb(). 141 */ 142 #define xdp_data_hard_end(xdp) \ 143 ((xdp)->data_hard_start + (xdp)->frame_sz - \ 144 SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) 145 146 static inline struct skb_shared_info * 147 xdp_get_shared_info_from_buff(struct xdp_buff *xdp) 148 { 149 return (struct skb_shared_info *)xdp_data_hard_end(xdp); 150 } 151 152 static __always_inline unsigned int xdp_get_buff_len(struct xdp_buff *xdp) 153 { 154 unsigned int len = xdp->data_end - xdp->data; 155 struct skb_shared_info *sinfo; 156 157 if (likely(!xdp_buff_has_frags(xdp))) 158 goto out; 159 160 sinfo = xdp_get_shared_info_from_buff(xdp); 161 len += sinfo->xdp_frags_size; 162 out: 163 return len; 164 } 165 166 struct xdp_frame { 167 void *data; 168 u16 len; 169 u16 headroom; 170 u32 metasize; /* uses lower 8-bits */ 171 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time, 172 * while mem info is valid on remote CPU. 173 */ 174 struct xdp_mem_info mem; 175 struct net_device *dev_rx; /* used by cpumap */ 176 u32 frame_sz; 177 u32 flags; /* supported values defined in xdp_buff_flags */ 178 }; 179 180 static __always_inline bool xdp_frame_has_frags(struct xdp_frame *frame) 181 { 182 return !!(frame->flags & XDP_FLAGS_HAS_FRAGS); 183 } 184 185 static __always_inline bool xdp_frame_is_frag_pfmemalloc(struct xdp_frame *frame) 186 { 187 return !!(frame->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC); 188 } 189 190 #define XDP_BULK_QUEUE_SIZE 16 191 struct xdp_frame_bulk { 192 int count; 193 void *xa; 194 void *q[XDP_BULK_QUEUE_SIZE]; 195 }; 196 197 static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq) 198 { 199 /* bq->count will be zero'ed when bq->xa gets updated */ 200 bq->xa = NULL; 201 } 202 203 static inline struct skb_shared_info * 204 xdp_get_shared_info_from_frame(struct xdp_frame *frame) 205 { 206 void *data_hard_start = frame->data - frame->headroom - sizeof(*frame); 207 208 return (struct skb_shared_info *)(data_hard_start + frame->frame_sz - 209 SKB_DATA_ALIGN(sizeof(struct skb_shared_info))); 210 } 211 212 struct xdp_cpumap_stats { 213 unsigned int redirect; 214 unsigned int pass; 215 unsigned int drop; 216 }; 217 218 /* Clear kernel pointers in xdp_frame */ 219 static inline void xdp_scrub_frame(struct xdp_frame *frame) 220 { 221 frame->data = NULL; 222 frame->dev_rx = NULL; 223 } 224 225 static inline void 226 xdp_update_skb_shared_info(struct sk_buff *skb, u8 nr_frags, 227 unsigned int size, unsigned int truesize, 228 bool pfmemalloc) 229 { 230 skb_shinfo(skb)->nr_frags = nr_frags; 231 232 skb->len += size; 233 skb->data_len += size; 234 skb->truesize += truesize; 235 skb->pfmemalloc |= pfmemalloc; 236 } 237 238 /* Avoids inlining WARN macro in fast-path */ 239 void xdp_warn(const char *msg, const char *func, const int line); 240 #define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__) 241 242 struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp); 243 struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf, 244 struct sk_buff *skb, 245 struct net_device *dev); 246 struct sk_buff *xdp_build_skb_from_frame(struct xdp_frame *xdpf, 247 struct net_device *dev); 248 int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp); 249 struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf); 250 251 static inline 252 void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp) 253 { 254 xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame); 255 xdp->data = frame->data; 256 xdp->data_end = frame->data + frame->len; 257 xdp->data_meta = frame->data - frame->metasize; 258 xdp->frame_sz = frame->frame_sz; 259 xdp->flags = frame->flags; 260 } 261 262 static inline 263 int xdp_update_frame_from_buff(struct xdp_buff *xdp, 264 struct xdp_frame *xdp_frame) 265 { 266 int metasize, headroom; 267 268 /* Assure headroom is available for storing info */ 269 headroom = xdp->data - xdp->data_hard_start; 270 metasize = xdp->data - xdp->data_meta; 271 metasize = metasize > 0 ? metasize : 0; 272 if (unlikely((headroom - metasize) < sizeof(*xdp_frame))) 273 return -ENOSPC; 274 275 /* Catch if driver didn't reserve tailroom for skb_shared_info */ 276 if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) { 277 XDP_WARN("Driver BUG: missing reserved tailroom"); 278 return -ENOSPC; 279 } 280 281 xdp_frame->data = xdp->data; 282 xdp_frame->len = xdp->data_end - xdp->data; 283 xdp_frame->headroom = headroom - sizeof(*xdp_frame); 284 xdp_frame->metasize = metasize; 285 xdp_frame->frame_sz = xdp->frame_sz; 286 xdp_frame->flags = xdp->flags; 287 288 return 0; 289 } 290 291 /* Convert xdp_buff to xdp_frame */ 292 static inline 293 struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp) 294 { 295 struct xdp_frame *xdp_frame; 296 297 if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) 298 return xdp_convert_zc_to_xdp_frame(xdp); 299 300 /* Store info in top of packet */ 301 xdp_frame = xdp->data_hard_start; 302 if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0)) 303 return NULL; 304 305 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */ 306 xdp_frame->mem = xdp->rxq->mem; 307 308 return xdp_frame; 309 } 310 311 void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct, 312 struct xdp_buff *xdp); 313 void xdp_return_frame(struct xdp_frame *xdpf); 314 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf); 315 void xdp_return_buff(struct xdp_buff *xdp); 316 void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq); 317 void xdp_return_frame_bulk(struct xdp_frame *xdpf, 318 struct xdp_frame_bulk *bq); 319 320 /* When sending xdp_frame into the network stack, then there is no 321 * return point callback, which is needed to release e.g. DMA-mapping 322 * resources with page_pool. Thus, have explicit function to release 323 * frame resources. 324 */ 325 void __xdp_release_frame(void *data, struct xdp_mem_info *mem); 326 static inline void xdp_release_frame(struct xdp_frame *xdpf) 327 { 328 struct xdp_mem_info *mem = &xdpf->mem; 329 struct skb_shared_info *sinfo; 330 int i; 331 332 /* Curr only page_pool needs this */ 333 if (mem->type != MEM_TYPE_PAGE_POOL) 334 return; 335 336 if (likely(!xdp_frame_has_frags(xdpf))) 337 goto out; 338 339 sinfo = xdp_get_shared_info_from_frame(xdpf); 340 for (i = 0; i < sinfo->nr_frags; i++) { 341 struct page *page = skb_frag_page(&sinfo->frags[i]); 342 343 __xdp_release_frame(page_address(page), mem); 344 } 345 out: 346 __xdp_release_frame(xdpf->data, mem); 347 } 348 349 static __always_inline unsigned int xdp_get_frame_len(struct xdp_frame *xdpf) 350 { 351 struct skb_shared_info *sinfo; 352 unsigned int len = xdpf->len; 353 354 if (likely(!xdp_frame_has_frags(xdpf))) 355 goto out; 356 357 sinfo = xdp_get_shared_info_from_frame(xdpf); 358 len += sinfo->xdp_frags_size; 359 out: 360 return len; 361 } 362 363 int __xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, 364 struct net_device *dev, u32 queue_index, 365 unsigned int napi_id, u32 frag_size); 366 static inline int 367 xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, 368 struct net_device *dev, u32 queue_index, 369 unsigned int napi_id) 370 { 371 return __xdp_rxq_info_reg(xdp_rxq, dev, queue_index, napi_id, 0); 372 } 373 374 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq); 375 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq); 376 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq); 377 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, 378 enum xdp_mem_type type, void *allocator); 379 void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq); 380 int xdp_reg_mem_model(struct xdp_mem_info *mem, 381 enum xdp_mem_type type, void *allocator); 382 void xdp_unreg_mem_model(struct xdp_mem_info *mem); 383 384 /* Drivers not supporting XDP metadata can use this helper, which 385 * rejects any room expansion for metadata as a result. 386 */ 387 static __always_inline void 388 xdp_set_data_meta_invalid(struct xdp_buff *xdp) 389 { 390 xdp->data_meta = xdp->data + 1; 391 } 392 393 static __always_inline bool 394 xdp_data_meta_unsupported(const struct xdp_buff *xdp) 395 { 396 return unlikely(xdp->data_meta > xdp->data); 397 } 398 399 static inline bool xdp_metalen_invalid(unsigned long metalen) 400 { 401 return (metalen & (sizeof(__u32) - 1)) || (metalen > 32); 402 } 403 404 struct xdp_attachment_info { 405 struct bpf_prog *prog; 406 u32 flags; 407 }; 408 409 struct netdev_bpf; 410 void xdp_attachment_setup(struct xdp_attachment_info *info, 411 struct netdev_bpf *bpf); 412 413 #define DEV_MAP_BULK_SIZE XDP_BULK_QUEUE_SIZE 414 415 #define XDP_METADATA_KFUNC_xxx \ 416 XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_TIMESTAMP, \ 417 bpf_xdp_metadata_rx_timestamp) \ 418 XDP_METADATA_KFUNC(XDP_METADATA_KFUNC_RX_HASH, \ 419 bpf_xdp_metadata_rx_hash) \ 420 421 enum { 422 #define XDP_METADATA_KFUNC(name, _) name, 423 XDP_METADATA_KFUNC_xxx 424 #undef XDP_METADATA_KFUNC 425 MAX_XDP_METADATA_KFUNC, 426 }; 427 428 #ifdef CONFIG_NET 429 u32 bpf_xdp_metadata_kfunc_id(int id); 430 bool bpf_dev_bound_kfunc_id(u32 btf_id); 431 void xdp_features_set_redirect_target(struct net_device *dev, bool support_sg); 432 void xdp_features_clear_redirect_target(struct net_device *dev); 433 #else 434 static inline u32 bpf_xdp_metadata_kfunc_id(int id) { return 0; } 435 static inline bool bpf_dev_bound_kfunc_id(u32 btf_id) { return false; } 436 437 static inline void 438 xdp_features_set_redirect_target(struct net_device *dev, bool support_sg) 439 { 440 } 441 442 static inline void 443 xdp_features_clear_redirect_target(struct net_device *dev) 444 { 445 } 446 #endif 447 448 #endif /* __LINUX_NET_XDP_H__ */ 449