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 
xdp_buff_has_frags(struct xdp_buff * xdp)91 static __always_inline bool xdp_buff_has_frags(struct xdp_buff *xdp)
92 {
93 	return !!(xdp->flags & XDP_FLAGS_HAS_FRAGS);
94 }
95 
xdp_buff_set_frags_flag(struct xdp_buff * xdp)96 static __always_inline void xdp_buff_set_frags_flag(struct xdp_buff *xdp)
97 {
98 	xdp->flags |= XDP_FLAGS_HAS_FRAGS;
99 }
100 
xdp_buff_clear_frags_flag(struct xdp_buff * xdp)101 static __always_inline void xdp_buff_clear_frags_flag(struct xdp_buff *xdp)
102 {
103 	xdp->flags &= ~XDP_FLAGS_HAS_FRAGS;
104 }
105 
xdp_buff_is_frag_pfmemalloc(struct xdp_buff * xdp)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 
xdp_buff_set_frag_pfmemalloc(struct xdp_buff * xdp)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
xdp_init_buff(struct xdp_buff * xdp,u32 frame_sz,struct xdp_rxq_info * rxq)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
xdp_prepare_buff(struct xdp_buff * xdp,unsigned char * hard_start,int headroom,int data_len,const bool meta_valid)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 *
xdp_get_shared_info_from_buff(struct xdp_buff * xdp)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 
xdp_get_buff_len(struct xdp_buff * xdp)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 
xdp_frame_has_frags(struct xdp_frame * frame)180 static __always_inline bool xdp_frame_has_frags(struct xdp_frame *frame)
181 {
182 	return !!(frame->flags & XDP_FLAGS_HAS_FRAGS);
183 }
184 
xdp_frame_is_frag_pfmemalloc(struct xdp_frame * frame)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 
xdp_frame_bulk_init(struct xdp_frame_bulk * bq)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 *
xdp_get_shared_info_from_frame(struct xdp_frame * frame)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 */
xdp_scrub_frame(struct xdp_frame * 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
xdp_update_skb_shared_info(struct sk_buff * skb,u8 nr_frags,unsigned int size,unsigned int truesize,bool pfmemalloc)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
xdp_convert_frame_to_buff(struct xdp_frame * frame,struct xdp_buff * xdp)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
xdp_update_frame_from_buff(struct xdp_buff * xdp,struct xdp_frame * xdp_frame)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
xdp_convert_buff_to_frame(struct xdp_buff * xdp)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);
xdp_release_frame(struct xdp_frame * xdpf)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 
xdp_get_frame_len(struct xdp_frame * xdpf)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
xdp_rxq_info_reg(struct xdp_rxq_info * xdp_rxq,struct net_device * dev,u32 queue_index,unsigned int napi_id)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
xdp_set_data_meta_invalid(struct xdp_buff * xdp)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
xdp_data_meta_unsupported(const struct xdp_buff * xdp)394 xdp_data_meta_unsupported(const struct xdp_buff *xdp)
395 {
396 	return unlikely(xdp->data_meta > xdp->data);
397 }
398 
xdp_metalen_invalid(unsigned long metalen)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
bpf_xdp_metadata_kfunc_id(int id)434 static inline u32 bpf_xdp_metadata_kfunc_id(int id) { return 0; }
bpf_dev_bound_kfunc_id(u32 btf_id)435 static inline bool bpf_dev_bound_kfunc_id(u32 btf_id) { return false; }
436 
437 static inline void
xdp_features_set_redirect_target(struct net_device * dev,bool support_sg)438 xdp_features_set_redirect_target(struct net_device *dev, bool support_sg)
439 {
440 }
441 
442 static inline void
xdp_features_clear_redirect_target(struct net_device * dev)443 xdp_features_clear_redirect_target(struct net_device *dev)
444 {
445 }
446 #endif
447 
448 #endif /* __LINUX_NET_XDP_H__ */
449