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;
62 } ____cacheline_aligned; /* perf critical, avoid false-sharing */
65 struct net_device *dev;
72 void *data_hard_start;
73 struct xdp_rxq_info *rxq;
74 struct xdp_txq_info *txq;
75 u32 frame_sz; /* frame size to deduce data_hard_end/reserved tailroom*/
78 /* Reserve memory area at end-of data area.
80 * This macro reserves tailroom in the XDP buffer by limiting the
81 * XDP/BPF data access to data_hard_end. Notice same area (and size)
82 * is used for XDP_PASS, when constructing the SKB via build_skb().
84 #define xdp_data_hard_end(xdp) \
85 ((xdp)->data_hard_start + (xdp)->frame_sz - \
86 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
88 static inline struct skb_shared_info *
89 xdp_get_shared_info_from_buff(struct xdp_buff *xdp)
91 return (struct skb_shared_info *)xdp_data_hard_end(xdp);
100 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
101 * while mem info is valid on remote CPU.
103 struct xdp_mem_info mem;
104 struct net_device *dev_rx; /* used by cpumap */
107 static inline struct skb_shared_info *
108 xdp_get_shared_info_from_frame(struct xdp_frame *frame)
110 void *data_hard_start = frame->data - frame->headroom - sizeof(*frame);
112 return (struct skb_shared_info *)(data_hard_start + frame->frame_sz -
113 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
116 /* Clear kernel pointers in xdp_frame */
117 static inline void xdp_scrub_frame(struct xdp_frame *frame)
120 frame->dev_rx = NULL;
123 /* Avoids inlining WARN macro in fast-path */
124 void xdp_warn(const char *msg, const char *func, const int line);
125 #define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__)
127 struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp);
130 void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp)
132 xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame);
133 xdp->data = frame->data;
134 xdp->data_end = frame->data + frame->len;
135 xdp->data_meta = frame->data - frame->metasize;
136 xdp->frame_sz = frame->frame_sz;
139 /* Convert xdp_buff to xdp_frame */
141 struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp)
143 struct xdp_frame *xdp_frame;
147 if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL)
148 return xdp_convert_zc_to_xdp_frame(xdp);
150 /* Assure headroom is available for storing info */
151 headroom = xdp->data - xdp->data_hard_start;
152 metasize = xdp->data - xdp->data_meta;
153 metasize = metasize > 0 ? metasize : 0;
154 if (unlikely((headroom - metasize) < sizeof(*xdp_frame)))
157 /* Catch if driver didn't reserve tailroom for skb_shared_info */
158 if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) {
159 XDP_WARN("Driver BUG: missing reserved tailroom");
163 /* Store info in top of packet */
164 xdp_frame = xdp->data_hard_start;
166 xdp_frame->data = xdp->data;
167 xdp_frame->len = xdp->data_end - xdp->data;
168 xdp_frame->headroom = headroom - sizeof(*xdp_frame);
169 xdp_frame->metasize = metasize;
170 xdp_frame->frame_sz = xdp->frame_sz;
172 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
173 xdp_frame->mem = xdp->rxq->mem;
178 void xdp_return_frame(struct xdp_frame *xdpf);
179 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf);
180 void xdp_return_buff(struct xdp_buff *xdp);
182 /* When sending xdp_frame into the network stack, then there is no
183 * return point callback, which is needed to release e.g. DMA-mapping
184 * resources with page_pool. Thus, have explicit function to release
187 void __xdp_release_frame(void *data, struct xdp_mem_info *mem);
188 static inline void xdp_release_frame(struct xdp_frame *xdpf)
190 struct xdp_mem_info *mem = &xdpf->mem;
192 /* Curr only page_pool needs this */
193 if (mem->type == MEM_TYPE_PAGE_POOL)
194 __xdp_release_frame(xdpf->data, mem);
197 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
198 struct net_device *dev, u32 queue_index);
199 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq);
200 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq);
201 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq);
202 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
203 enum xdp_mem_type type, void *allocator);
204 void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq);
206 /* Drivers not supporting XDP metadata can use this helper, which
207 * rejects any room expansion for metadata as a result.
209 static __always_inline void
210 xdp_set_data_meta_invalid(struct xdp_buff *xdp)
212 xdp->data_meta = xdp->data + 1;
215 static __always_inline bool
216 xdp_data_meta_unsupported(const struct xdp_buff *xdp)
218 return unlikely(xdp->data_meta > xdp->data);
221 struct xdp_attachment_info {
222 struct bpf_prog *prog;
227 int xdp_attachment_query(struct xdp_attachment_info *info,
228 struct netdev_bpf *bpf);
229 bool xdp_attachment_flags_ok(struct xdp_attachment_info *info,
230 struct netdev_bpf *bpf);
231 void xdp_attachment_setup(struct xdp_attachment_info *info,
232 struct netdev_bpf *bpf);
234 #define DEV_MAP_BULK_SIZE 16
236 #endif /* __LINUX_NET_XDP_H__ */