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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 carries 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 are 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 unregister (which
34 * also applies 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 unsigned int napi_id;
63 u32 frag_size;
64} ____cacheline_aligned; /* perf critical, avoid false-sharing */
65
66struct xdp_txq_info {
67 struct net_device *dev;
68};
69
70enum xdp_buff_flags {
71 XDP_FLAGS_HAS_FRAGS = BIT(0), /* non-linear xdp buff */
72 XDP_FLAGS_FRAGS_PF_MEMALLOC = BIT(1), /* xdp paged memory is under
73 * pressure
74 */
75};
76
77struct xdp_buff {
78 void *data;
79 void *data_end;
80 void *data_meta;
81 void *data_hard_start;
82 struct xdp_rxq_info *rxq;
83 struct xdp_txq_info *txq;
84 u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/
85 u32 flags; /* supported values defined in xdp_buff_flags */
86};
87
88static __always_inline bool xdp_buff_has_frags(struct xdp_buff *xdp)
89{
90 return !!(xdp->flags & XDP_FLAGS_HAS_FRAGS);
91}
92
93static __always_inline void xdp_buff_set_frags_flag(struct xdp_buff *xdp)
94{
95 xdp->flags |= XDP_FLAGS_HAS_FRAGS;
96}
97
98static __always_inline void xdp_buff_clear_frags_flag(struct xdp_buff *xdp)
99{
100 xdp->flags &= ~XDP_FLAGS_HAS_FRAGS;
101}
102
103static __always_inline bool xdp_buff_is_frag_pfmemalloc(struct xdp_buff *xdp)
104{
105 return !!(xdp->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC);
106}
107
108static __always_inline void xdp_buff_set_frag_pfmemalloc(struct xdp_buff *xdp)
109{
110 xdp->flags |= XDP_FLAGS_FRAGS_PF_MEMALLOC;
111}
112
113static __always_inline void
114xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq)
115{
116 xdp->frame_sz = frame_sz;
117 xdp->rxq = rxq;
118 xdp->flags = 0;
119}
120
121static __always_inline void
122xdp_prepare_buff(struct xdp_buff *xdp, unsigned char *hard_start,
123 int headroom, int data_len, const bool meta_valid)
124{
125 unsigned char *data = hard_start + headroom;
126
127 xdp->data_hard_start = hard_start;
128 xdp->data = data;
129 xdp->data_end = data + data_len;
130 xdp->data_meta = meta_valid ? data : data + 1;
131}
132
133/* Reserve memory area at end-of data area.
134 *
135 * This macro reserves tailroom in the XDP buffer by limiting the
136 * XDP/BPF data access to data_hard_end. Notice same area (and size)
137 * is used for XDP_PASS, when constructing the SKB via build_skb().
138 */
139#define xdp_data_hard_end(xdp) \
140 ((xdp)->data_hard_start + (xdp)->frame_sz - \
141 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
142
143static inline struct skb_shared_info *
144xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
145{
146 return (struct skb_shared_info *)xdp_data_hard_end(xdp);
147}
148
149static __always_inline unsigned int xdp_get_buff_len(struct xdp_buff *xdp)
150{
151 unsigned int len = xdp->data_end - xdp->data;
152 struct skb_shared_info *sinfo;
153
154 if (likely(!xdp_buff_has_frags(xdp)))
155 goto out;
156
157 sinfo = xdp_get_shared_info_from_buff(xdp);
158 len += sinfo->xdp_frags_size;
159out:
160 return len;
161}
162
163struct xdp_frame {
164 void *data;
165 u16 len;
166 u16 headroom;
167 u32 metasize; /* uses lower 8-bits */
168 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
169 * while mem info is valid on remote CPU.
170 */
171 struct xdp_mem_info mem;
172 struct net_device *dev_rx; /* used by cpumap */
173 u32 frame_sz;
174 u32 flags; /* supported values defined in xdp_buff_flags */
175};
176
177static __always_inline bool xdp_frame_has_frags(struct xdp_frame *frame)
178{
179 return !!(frame->flags & XDP_FLAGS_HAS_FRAGS);
180}
181
182static __always_inline bool xdp_frame_is_frag_pfmemalloc(struct xdp_frame *frame)
183{
184 return !!(frame->flags & XDP_FLAGS_FRAGS_PF_MEMALLOC);
185}
186
187#define XDP_BULK_QUEUE_SIZE 16
188struct xdp_frame_bulk {
189 int count;
190 void *xa;
191 void *q[XDP_BULK_QUEUE_SIZE];
192};
193
194static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq)
195{
196 /* bq->count will be zero'ed when bq->xa gets updated */
197 bq->xa = NULL;
198}
199
200static inline struct skb_shared_info *
201xdp_get_shared_info_from_frame(struct xdp_frame *frame)
202{
203 void *data_hard_start = frame->data - frame->headroom - sizeof(*frame);
204
205 return (struct skb_shared_info *)(data_hard_start + frame->frame_sz -
206 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
207}
208
209struct xdp_cpumap_stats {
210 unsigned int redirect;
211 unsigned int pass;
212 unsigned int drop;
213};
214
215/* Clear kernel pointers in xdp_frame */
216static inline void xdp_scrub_frame(struct xdp_frame *frame)
217{
218 frame->data = NULL;
219 frame->dev_rx = NULL;
220}
221
222static inline void
223xdp_update_skb_shared_info(struct sk_buff *skb, u8 nr_frags,
224 unsigned int size, unsigned int truesize,
225 bool pfmemalloc)
226{
227 skb_shinfo(skb)->nr_frags = nr_frags;
228
229 skb->len += size;
230 skb->data_len += size;
231 skb->truesize += truesize;
232 skb->pfmemalloc |= pfmemalloc;
233}
234
235/* Avoids inlining WARN macro in fast-path */
236void xdp_warn(const char *msg, const char *func, const int line);
237#define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__)
238
239struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp);
240struct sk_buff *__xdp_build_skb_from_frame(struct xdp_frame *xdpf,
241 struct sk_buff *skb,
242 struct net_device *dev);
243struct sk_buff *xdp_build_skb_from_frame(struct xdp_frame *xdpf,
244 struct net_device *dev);
245int xdp_alloc_skb_bulk(void **skbs, int n_skb, gfp_t gfp);
246struct xdp_frame *xdpf_clone(struct xdp_frame *xdpf);
247
248static inline
249void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp)
250{
251 xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame);
252 xdp->data = frame->data;
253 xdp->data_end = frame->data + frame->len;
254 xdp->data_meta = frame->data - frame->metasize;
255 xdp->frame_sz = frame->frame_sz;
256 xdp->flags = frame->flags;
257}
258
259static inline
260int xdp_update_frame_from_buff(struct xdp_buff *xdp,
261 struct xdp_frame *xdp_frame)
262{
263 int metasize, headroom;
264
265 /* Assure headroom is available for storing info */
266 headroom = xdp->data - xdp->data_hard_start;
267 metasize = xdp->data - xdp->data_meta;
268 metasize = metasize > 0 ? metasize : 0;
269 if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
270 return -ENOSPC;
271
272 /* Catch if driver didn't reserve tailroom for skb_shared_info */
273 if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) {
274 XDP_WARN("Driver BUG: missing reserved tailroom");
275 return -ENOSPC;
276 }
277
278 xdp_frame->data = xdp->data;
279 xdp_frame->len = xdp->data_end - xdp->data;
280 xdp_frame->headroom = headroom - sizeof(*xdp_frame);
281 xdp_frame->metasize = metasize;
282 xdp_frame->frame_sz = xdp->frame_sz;
283 xdp_frame->flags = xdp->flags;
284
285 return 0;
286}
287
288/* Convert xdp_buff to xdp_frame */
289static inline
290struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
291{
292 struct xdp_frame *xdp_frame;
293
294 if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL)
295 return xdp_convert_zc_to_xdp_frame(xdp);
296
297 /* Store info in top of packet */
298 xdp_frame = xdp->data_hard_start;
299 if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0))
300 return NULL;
301
302 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
303 xdp_frame->mem = xdp->rxq->mem;
304
305 return xdp_frame;
306}
307
308void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
309 struct xdp_buff *xdp);
310void xdp_return_frame(struct xdp_frame *xdpf);
311void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
312void xdp_return_buff(struct xdp_buff *xdp);
313void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq);
314void xdp_return_frame_bulk(struct xdp_frame *xdpf,
315 struct xdp_frame_bulk *bq);
316
317/* When sending xdp_frame into the network stack, then there is no
318 * return point callback, which is needed to release e.g. DMA-mapping
319 * resources with page_pool. Thus, have explicit function to release
320 * frame resources.
321 */
322void __xdp_release_frame(void *data, struct xdp_mem_info *mem);
323static inline void xdp_release_frame(struct xdp_frame *xdpf)
324{
325 struct xdp_mem_info *mem = &xdpf->mem;
326 struct skb_shared_info *sinfo;
327 int i;
328
329 /* Curr only page_pool needs this */
330 if (mem->type != MEM_TYPE_PAGE_POOL)
331 return;
332
333 if (likely(!xdp_frame_has_frags(xdpf)))
334 goto out;
335
336 sinfo = xdp_get_shared_info_from_frame(xdpf);
337 for (i = 0; i < sinfo->nr_frags; i++) {
338 struct page *page = skb_frag_page(&sinfo->frags[i]);
339
340 __xdp_release_frame(page_address(page), mem);
341 }
342out:
343 __xdp_release_frame(xdpf->data, mem);
344}
345
346static __always_inline unsigned int xdp_get_frame_len(struct xdp_frame *xdpf)
347{
348 struct skb_shared_info *sinfo;
349 unsigned int len = xdpf->len;
350
351 if (likely(!xdp_frame_has_frags(xdpf)))
352 goto out;
353
354 sinfo = xdp_get_shared_info_from_frame(xdpf);
355 len += sinfo->xdp_frags_size;
356out:
357 return len;
358}
359
360int __xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
361 struct net_device *dev, u32 queue_index,
362 unsigned int napi_id, u32 frag_size);
363static inline int
364xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
365 struct net_device *dev, u32 queue_index,
366 unsigned int napi_id)
367{
368 return __xdp_rxq_info_reg(xdp_rxq, dev, queue_index, napi_id, 0);
369}
370
371void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
372void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);
373bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
374int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
375 enum xdp_mem_type type, void *allocator);
376void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq);
377int xdp_reg_mem_model(struct xdp_mem_info *mem,
378 enum xdp_mem_type type, void *allocator);
379void xdp_unreg_mem_model(struct xdp_mem_info *mem);
380
381/* Drivers not supporting XDP metadata can use this helper, which
382 * rejects any room expansion for metadata as a result.
383 */
384static __always_inline void
385xdp_set_data_meta_invalid(struct xdp_buff *xdp)
386{
387 xdp->data_meta = xdp->data + 1;
388}
389
390static __always_inline bool
391xdp_data_meta_unsupported(const struct xdp_buff *xdp)
392{
393 return unlikely(xdp->data_meta > xdp->data);
394}
395
396static inline bool xdp_metalen_invalid(unsigned long metalen)
397{
398 return (metalen & (sizeof(__u32) - 1)) || (metalen > 32);
399}
400
401struct xdp_attachment_info {
402 struct bpf_prog *prog;
403 u32 flags;
404};
405
406struct netdev_bpf;
407void xdp_attachment_setup(struct xdp_attachment_info *info,
408 struct netdev_bpf *bpf);
409
410#define DEV_MAP_BULK_SIZE XDP_BULK_QUEUE_SIZE
411
412#endif /* __LINUX_NET_XDP_H__ */