Line data Source code
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 0 : xdp_init_buff(struct xdp_buff *xdp, u32 frame_sz, struct xdp_rxq_info *rxq)
81 : {
82 0 : xdp->frame_sz = frame_sz;
83 0 : xdp->rxq = rxq;
84 : }
85 :
86 : static __always_inline void
87 0 : xdp_prepare_buff(struct xdp_buff *xdp, unsigned char *hard_start,
88 : int headroom, int data_len, const bool meta_valid)
89 : {
90 0 : unsigned char *data = hard_start + headroom;
91 :
92 0 : xdp->data_hard_start = hard_start;
93 0 : xdp->data = data;
94 0 : xdp->data_end = data + data_len;
95 0 : 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 0 : static inline void xdp_scrub_frame(struct xdp_frame *frame)
157 : {
158 0 : frame->data = NULL;
159 0 : 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 0 : int xdp_update_frame_from_buff(struct xdp_buff *xdp,
186 : struct xdp_frame *xdp_frame)
187 : {
188 0 : int metasize, headroom;
189 :
190 : /* Assure headroom is available for storing info */
191 0 : headroom = xdp->data - xdp->data_hard_start;
192 0 : metasize = xdp->data - xdp->data_meta;
193 0 : metasize = metasize > 0 ? metasize : 0;
194 0 : if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
195 : return -ENOSPC;
196 :
197 : /* Catch if driver didn't reserve tailroom for skb_shared_info */
198 0 : if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) {
199 0 : XDP_WARN("Driver BUG: missing reserved tailroom");
200 0 : return -ENOSPC;
201 : }
202 :
203 0 : xdp_frame->data = xdp->data;
204 0 : xdp_frame->len = xdp->data_end - xdp->data;
205 0 : xdp_frame->headroom = headroom - sizeof(*xdp_frame);
206 0 : xdp_frame->metasize = metasize;
207 0 : xdp_frame->frame_sz = xdp->frame_sz;
208 :
209 0 : return 0;
210 : }
211 :
212 : /* Convert xdp_buff to xdp_frame */
213 : static inline
214 0 : struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
215 : {
216 0 : struct xdp_frame *xdp_frame;
217 :
218 0 : if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL)
219 0 : return xdp_convert_zc_to_xdp_frame(xdp);
220 :
221 : /* Store info in top of packet */
222 0 : xdp_frame = xdp->data_hard_start;
223 0 : 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 0 : xdp_frame->mem = xdp->rxq->mem;
228 :
229 0 : 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 0 : static inline void xdp_release_frame(struct xdp_frame *xdpf)
246 : {
247 0 : struct xdp_mem_info *mem = &xdpf->mem;
248 :
249 : /* Curr only page_pool needs this */
250 0 : if (mem->type == MEM_TYPE_PAGE_POOL)
251 0 : __xdp_release_frame(xdpf->data, mem);
252 0 : }
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 0 : xdp_data_meta_unsupported(const struct xdp_buff *xdp)
274 : {
275 0 : 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__ */
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