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 } ____cacheline_aligned; /* perf critical, avoid false-sharing */ 63 64 struct xdp_txq_info { 65 struct net_device *dev; 66 }; 67 68 struct xdp_buff { 69 void *data; 70 void *data_end; 71 void *data_meta; 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*/ 76 }; 77 78 /* Reserve memory area at end-of data area. 79 * 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(). 83 */ 84 #define xdp_data_hard_end(xdp) \ 85 ((xdp)->data_hard_start + (xdp)->frame_sz - \ 86 SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) 87 88 struct xdp_frame { 89 void *data; 90 u16 len; 91 u16 headroom; 92 u32 metasize:8; 93 u32 frame_sz:24; 94 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time, 95 * while mem info is valid on remote CPU. 96 */ 97 struct xdp_mem_info mem; 98 struct net_device *dev_rx; /* used by cpumap */ 99 }; 100 101 /* Clear kernel pointers in xdp_frame */ 102 static inline void xdp_scrub_frame(struct xdp_frame *frame) 103 { 104 frame->data = NULL; 105 frame->dev_rx = NULL; 106 } 107 108 /* Avoids inlining WARN macro in fast-path */ 109 void xdp_warn(const char *msg, const char *func, const int line); 110 #define XDP_WARN(msg) xdp_warn(msg, __func__, __LINE__) 111 112 struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp); 113 114 static inline 115 void xdp_convert_frame_to_buff(struct xdp_frame *frame, struct xdp_buff *xdp) 116 { 117 xdp->data_hard_start = frame->data - frame->headroom - sizeof(*frame); 118 xdp->data = frame->data; 119 xdp->data_end = frame->data + frame->len; 120 xdp->data_meta = frame->data - frame->metasize; 121 xdp->frame_sz = frame->frame_sz; 122 } 123 124 /* Convert xdp_buff to xdp_frame */ 125 static inline 126 struct xdp_frame *xdp_convert_buff_to_frame(struct xdp_buff *xdp) 127 { 128 struct xdp_frame *xdp_frame; 129 int metasize; 130 int headroom; 131 132 if (xdp->rxq->mem.type == MEM_TYPE_XSK_BUFF_POOL) 133 return xdp_convert_zc_to_xdp_frame(xdp); 134 135 /* Assure headroom is available for storing info */ 136 headroom = xdp->data - xdp->data_hard_start; 137 metasize = xdp->data - xdp->data_meta; 138 metasize = metasize > 0 ? metasize : 0; 139 if (unlikely((headroom - metasize) < sizeof(*xdp_frame))) 140 return NULL; 141 142 /* Catch if driver didn't reserve tailroom for skb_shared_info */ 143 if (unlikely(xdp->data_end > xdp_data_hard_end(xdp))) { 144 XDP_WARN("Driver BUG: missing reserved tailroom"); 145 return NULL; 146 } 147 148 /* Store info in top of packet */ 149 xdp_frame = xdp->data_hard_start; 150 151 xdp_frame->data = xdp->data; 152 xdp_frame->len = xdp->data_end - xdp->data; 153 xdp_frame->headroom = headroom - sizeof(*xdp_frame); 154 xdp_frame->metasize = metasize; 155 xdp_frame->frame_sz = xdp->frame_sz; 156 157 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */ 158 xdp_frame->mem = xdp->rxq->mem; 159 160 return xdp_frame; 161 } 162 163 void xdp_return_frame(struct xdp_frame *xdpf); 164 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf); 165 void xdp_return_buff(struct xdp_buff *xdp); 166 167 /* When sending xdp_frame into the network stack, then there is no 168 * return point callback, which is needed to release e.g. DMA-mapping 169 * resources with page_pool. Thus, have explicit function to release 170 * frame resources. 171 */ 172 void __xdp_release_frame(void *data, struct xdp_mem_info *mem); 173 static inline void xdp_release_frame(struct xdp_frame *xdpf) 174 { 175 struct xdp_mem_info *mem = &xdpf->mem; 176 177 /* Curr only page_pool needs this */ 178 if (mem->type == MEM_TYPE_PAGE_POOL) 179 __xdp_release_frame(xdpf->data, mem); 180 } 181 182 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, 183 struct net_device *dev, u32 queue_index); 184 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq); 185 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq); 186 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq); 187 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, 188 enum xdp_mem_type type, void *allocator); 189 void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq); 190 191 /* Drivers not supporting XDP metadata can use this helper, which 192 * rejects any room expansion for metadata as a result. 193 */ 194 static __always_inline void 195 xdp_set_data_meta_invalid(struct xdp_buff *xdp) 196 { 197 xdp->data_meta = xdp->data + 1; 198 } 199 200 static __always_inline bool 201 xdp_data_meta_unsupported(const struct xdp_buff *xdp) 202 { 203 return unlikely(xdp->data_meta > xdp->data); 204 } 205 206 struct xdp_attachment_info { 207 struct bpf_prog *prog; 208 u32 flags; 209 }; 210 211 struct netdev_bpf; 212 int xdp_attachment_query(struct xdp_attachment_info *info, 213 struct netdev_bpf *bpf); 214 bool xdp_attachment_flags_ok(struct xdp_attachment_info *info, 215 struct netdev_bpf *bpf); 216 void xdp_attachment_setup(struct xdp_attachment_info *info, 217 struct netdev_bpf *bpf); 218 219 #define DEV_MAP_BULK_SIZE 16 220 221 #endif /* __LINUX_NET_XDP_H__ */ 222