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 /* Reserve memory area at end-of data area. 80 * 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(). 84 */ 85 #define xdp_data_hard_end(xdp) \ 86 ((xdp)->data_hard_start + (xdp)->frame_sz - \ 87 SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) 88 89 static inline struct skb_shared_info * 90 xdp_get_shared_info_from_buff(struct xdp_buff *xdp) 91 { 92 return (struct skb_shared_info *)xdp_data_hard_end(xdp); 93 } 94 95 struct xdp_frame { 96 void *data; 97 u16 len; 98 u16 headroom; 99 u32 metasize:8; 100 u32 frame_sz:24; 101 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time, 102 * while mem info is valid on remote CPU. 103 */ 104 struct xdp_mem_info mem; 105 struct net_device *dev_rx; /* used by cpumap */ 106 }; 107 108 #define XDP_BULK_QUEUE_SIZE 16 109 struct xdp_frame_bulk { 110 int count; 111 void *xa; 112 void *q[XDP_BULK_QUEUE_SIZE]; 113 }; 114 115 static __always_inline void xdp_frame_bulk_init(struct xdp_frame_bulk *bq) 116 { 117 /* bq->count will be zero'ed when bq->xa gets updated */ 118 bq->xa = NULL; 119 } 120 121 static inline struct skb_shared_info * 122 xdp_get_shared_info_from_frame(struct xdp_frame *frame) 123 { 124 void *data_hard_start = frame->data - frame->headroom - sizeof(*frame); 125 126 return (struct skb_shared_info *)(data_hard_start + frame->frame_sz - 127 SKB_DATA_ALIGN(sizeof(struct skb_shared_info))); 128 } 129 130 struct xdp_cpumap_stats { 131 unsigned int redirect; 132 unsigned int pass; 133 unsigned int drop; 134 }; 135 136 /* Clear kernel pointers in xdp_frame */ 137 static inline void xdp_scrub_frame(struct xdp_frame *frame) 138 { 139 frame->data = NULL; 140 frame->dev_rx = NULL; 141 } 142 143 /* 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__) 146 147 struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp); 148 149 static inline 150 void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp) 151 { 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; 157 } 158 159 static inline 160 int xdp_update_frame_from_buff(struct xdp_buff *xdp, 161 struct xdp_frame *xdp_frame) 162 { 163 int metasize, headroom; 164 165 /* 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))) 170 return -ENOSPC; 171 172 /* 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"); 175 return -ENOSPC; 176 } 177 178 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; 183 184 return 0; 185 } 186 187 /* Convert xdp_buff to xdp_frame */ 188 static inline 189 struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp) 190 { 191 struct xdp_frame *xdp_frame; 192 193 if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) 194 return xdp_convert_zc_to_xdp_frame(xdp); 195 196 /* 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)) 199 return NULL; 200 201 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */ 202 xdp_frame->mem = xdp->rxq->mem; 203 204 return xdp_frame; 205 } 206 207 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); 213 214 /* 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 217 * frame resources. 218 */ 219 void __xdp_release_frame(void *data, struct xdp_mem_info *mem); 220 static inline void xdp_release_frame(struct xdp_frame *xdpf) 221 { 222 struct xdp_mem_info *mem = &xdpf->mem; 223 224 /* Curr only page_pool needs this */ 225 if (mem->type == MEM_TYPE_PAGE_POOL) 226 __xdp_release_frame(xdpf->data, mem); 227 } 228 229 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); 237 238 /* Drivers not supporting XDP metadata can use this helper, which 239 * rejects any room expansion for metadata as a result. 240 */ 241 static __always_inline void 242 xdp_set_data_meta_invalid(struct xdp_buff *xdp) 243 { 244 xdp->data_meta = xdp->data + 1; 245 } 246 247 static __always_inline bool 248 xdp_data_meta_unsupported(const struct xdp_buff *xdp) 249 { 250 return unlikely(xdp->data_meta > xdp->data); 251 } 252 253 struct xdp_attachment_info { 254 struct bpf_prog *prog; 255 u32 flags; 256 }; 257 258 struct netdev_bpf; 259 bool xdp_attachment_flags_ok(struct xdp_attachment_info *info, 260 struct netdev_bpf *bpf); 261 void xdp_attachment_setup(struct xdp_attachment_info *info, 262 struct netdev_bpf *bpf); 263 264 #define DEV_MAP_BULK_SIZE XDP_BULK_QUEUE_SIZE 265 266 #endif /* __LINUX_NET_XDP_H__ */ 267