1 /* SPDX-License-Identifier: GPL-2.0-only */
4 * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
6 #ifndef __LINUX_NET_XDP_H__
7 #define __LINUX_NET_XDP_H__
9 #include <linux/skbuff.h> /* skb_shared_info */
12 * DOC: XDP RX-queue information
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.
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
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.
27 * The driver usage API is a register and unregister API.
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.
39 MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */
40 MEM_TYPE_PAGE_ORDER0, /* Orig XDP full page model */
42 MEM_TYPE_XSK_BUFF_POOL,
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
51 u32 type; /* enum xdp_mem_type, but known size type */
58 struct net_device *dev;
61 struct xdp_mem_info mem;
63 } ____cacheline_aligned; /* perf critical, avoid false-sharing */
66 struct net_device *dev;
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*/
79 /* Reserve memory area at end-of data area.
81 * This macro reserves tailroom in the XDP buffer by limiting the
82 * XDP/BPF data access to data_hard_end. Notice same area (and size)
83 * is used for XDP_PASS, when constructing the SKB via build_skb().
85 #define xdp_data_hard_end(xdp) \
86 ((xdp)->data_hard_start + (xdp)->frame_sz - \
87 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
89 static inline struct skb_shared_info *
90 xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
92 return (struct skb_shared_info *)xdp_data_hard_end(xdp);
101 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
102 * while mem info is valid on remote CPU.
104 struct xdp_mem_info mem;
105 struct net_device *dev_rx; /* used by cpumap */
108 #define XDP_BULK_QUEUE_SIZE 16
109 struct xdp_frame_bulk {
112 void *q[XDP_BULK_QUEUE_SIZE];
115 static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq)
117 /* bq->count will be zero'ed when bq->xa gets updated */
121 static inline struct skb_shared_info *
122 xdp_get_shared_info_from_frame(struct xdp_frame *frame)
124 void *data_hard_start = frame->data - frame->headroom - sizeof(*frame);
126 return (struct skb_shared_info *)(data_hard_start + frame->frame_sz -
127 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
130 struct xdp_cpumap_stats {
131 unsigned int redirect;
136 /* Clear kernel pointers in xdp_frame */
137 static inline void xdp_scrub_frame(struct xdp_frame *frame)
140 frame->dev_rx = NULL;
143 /* Avoids inlining WARN macro in fast-path */
144 void xdp_warn(const char *msg, const char *func, const int line);
145 #define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__)
147 struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp);
150 void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp)
152 xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame);
153 xdp->data = frame->data;
154 xdp->data_end = frame->data + frame->len;
155 xdp->data_meta = frame->data - frame->metasize;
156 xdp->frame_sz = frame->frame_sz;
160 int xdp_update_frame_from_buff(struct xdp_buff *xdp,
161 struct xdp_frame *xdp_frame)
163 int metasize, headroom;
165 /* Assure headroom is available for storing info */
166 headroom = xdp->data - xdp->data_hard_start;
167 metasize = xdp->data - xdp->data_meta;
168 metasize = metasize > 0 ? metasize : 0;
169 if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
172 /* Catch if driver didn't reserve tailroom for skb_shared_info */
173 if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) {
174 XDP_WARN("Driver BUG: missing reserved tailroom");
178 xdp_frame->data = xdp->data;
179 xdp_frame->len = xdp->data_end - xdp->data;
180 xdp_frame->headroom = headroom - sizeof(*xdp_frame);
181 xdp_frame->metasize = metasize;
182 xdp_frame->frame_sz = xdp->frame_sz;
187 /* Convert xdp_buff to xdp_frame */
189 struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
191 struct xdp_frame *xdp_frame;
193 if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL)
194 return xdp_convert_zc_to_xdp_frame(xdp);
196 /* Store info in top of packet */
197 xdp_frame = xdp->data_hard_start;
198 if (unlikely(xdp_update_frame_from_buff(xdp, xdp_frame) < 0))
201 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
202 xdp_frame->mem = xdp->rxq->mem;
207 void xdp_return_frame(struct xdp_frame *xdpf);
208 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
209 void xdp_return_buff(struct xdp_buff *xdp);
210 void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq);
211 void xdp_return_frame_bulk(struct xdp_frame *xdpf,
212 struct xdp_frame_bulk *bq);
214 /* When sending xdp_frame into the network stack, then there is no
215 * return point callback, which is needed to release e.g. DMA-mapping
216 * resources with page_pool. Thus, have explicit function to release
219 void __xdp_release_frame(void *data, struct xdp_mem_info *mem);
220 static inline void xdp_release_frame(struct xdp_frame *xdpf)
222 struct xdp_mem_info *mem = &xdpf->mem;
224 /* Curr only page_pool needs this */
225 if (mem->type == MEM_TYPE_PAGE_POOL)
226 __xdp_release_frame(xdpf->data, mem);
229 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
230 struct net_device *dev, u32 queue_index, unsigned int napi_id);
231 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
232 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);
233 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
234 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
235 enum xdp_mem_type type, void *allocator);
236 void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq);
238 /* Drivers not supporting XDP metadata can use this helper, which
239 * rejects any room expansion for metadata as a result.
241 static __always_inline void
242 xdp_set_data_meta_invalid(struct xdp_buff *xdp)
244 xdp->data_meta = xdp->data + 1;
247 static __always_inline bool
248 xdp_data_meta_unsupported(const struct xdp_buff *xdp)
250 return unlikely(xdp->data_meta > xdp->data);
253 struct xdp_attachment_info {
254 struct bpf_prog *prog;
259 void xdp_attachment_setup(struct xdp_attachment_info *info,
260 struct netdev_bpf *bpf);
262 #define DEV_MAP_BULK_SIZE XDP_BULK_QUEUE_SIZE
264 #endif /* __LINUX_NET_XDP_H__ */