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 /** 10 * DOC: XDP RX-queue information 11 * 12 * The XDP RX-queue info (xdp_rxq_info) is associated with the driver 13 * level RX-ring queues. It is information that is specific to how 14 * the driver have configured a given RX-ring queue. 15 * 16 * Each xdp_buff frame received in the driver carry a (pointer) 17 * reference to this xdp_rxq_info structure. This provides the XDP 18 * data-path read-access to RX-info for both kernel and bpf-side 19 * (limited subset). 20 * 21 * For now, direct access is only safe while running in NAPI/softirq 22 * context. Contents is read-mostly and must not be updated during 23 * driver NAPI/softirq poll. 24 * 25 * The driver usage API is a register and unregister API. 26 * 27 * The struct is not directly tied to the XDP prog. A new XDP prog 28 * can be attached as long as it doesn't change the underlying 29 * RX-ring. If the RX-ring does change significantly, the NIC driver 30 * naturally need to stop the RX-ring before purging and reallocating 31 * memory. In that process the driver MUST call unregistor (which 32 * also apply for driver shutdown and unload). The register API is 33 * also mandatory during RX-ring setup. 34 */ 35 36 enum xdp_mem_type { 37 MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */ 38 MEM_TYPE_PAGE_ORDER0, /* Orig XDP full page model */ 39 MEM_TYPE_PAGE_POOL, 40 MEM_TYPE_ZERO_COPY, 41 MEM_TYPE_MAX, 42 }; 43 44 /* XDP flags for ndo_xdp_xmit */ 45 #define XDP_XMIT_FLUSH (1U << 0) /* doorbell signal consumer */ 46 #define XDP_XMIT_FLAGS_MASK XDP_XMIT_FLUSH 47 48 struct xdp_mem_info { 49 u32 type; /* enum xdp_mem_type, but known size type */ 50 u32 id; 51 }; 52 53 struct page_pool; 54 55 struct zero_copy_allocator { 56 void (*free)(struct zero_copy_allocator *zca, unsigned long handle); 57 }; 58 59 struct xdp_rxq_info { 60 struct net_device *dev; 61 u32 queue_index; 62 u32 reg_state; 63 struct xdp_mem_info mem; 64 } ____cacheline_aligned; /* perf critical, avoid false-sharing */ 65 66 struct xdp_buff { 67 void *data; 68 void *data_end; 69 void *data_meta; 70 void *data_hard_start; 71 unsigned long handle; 72 struct xdp_rxq_info *rxq; 73 }; 74 75 struct xdp_frame { 76 void *data; 77 u16 len; 78 u16 headroom; 79 u16 metasize; 80 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time, 81 * while mem info is valid on remote CPU. 82 */ 83 struct xdp_mem_info mem; 84 struct net_device *dev_rx; /* used by cpumap */ 85 }; 86 87 /* Clear kernel pointers in xdp_frame */ 88 static inline void xdp_scrub_frame(struct xdp_frame *frame) 89 { 90 frame->data = NULL; 91 frame->dev_rx = NULL; 92 } 93 94 struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp); 95 96 /* Convert xdp_buff to xdp_frame */ 97 static inline 98 struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp) 99 { 100 struct xdp_frame *xdp_frame; 101 int metasize; 102 int headroom; 103 104 if (xdp->rxq->mem.type == MEM_TYPE_ZERO_COPY) 105 return xdp_convert_zc_to_xdp_frame(xdp); 106 107 /* Assure headroom is available for storing info */ 108 headroom = xdp->data - xdp->data_hard_start; 109 metasize = xdp->data - xdp->data_meta; 110 metasize = metasize > 0 ? metasize : 0; 111 if (unlikely((headroom - metasize) < sizeof(*xdp_frame))) 112 return NULL; 113 114 /* Store info in top of packet */ 115 xdp_frame = xdp->data_hard_start; 116 117 xdp_frame->data = xdp->data; 118 xdp_frame->len = xdp->data_end - xdp->data; 119 xdp_frame->headroom = headroom - sizeof(*xdp_frame); 120 xdp_frame->metasize = metasize; 121 122 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */ 123 xdp_frame->mem = xdp->rxq->mem; 124 125 return xdp_frame; 126 } 127 128 void xdp_return_frame(struct xdp_frame *xdpf); 129 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf); 130 void xdp_return_buff(struct xdp_buff *xdp); 131 132 /* When sending xdp_frame into the network stack, then there is no 133 * return point callback, which is needed to release e.g. DMA-mapping 134 * resources with page_pool. Thus, have explicit function to release 135 * frame resources. 136 */ 137 void __xdp_release_frame(void *data, struct xdp_mem_info *mem); 138 static inline void xdp_release_frame(struct xdp_frame *xdpf) 139 { 140 struct xdp_mem_info *mem = &xdpf->mem; 141 142 /* Curr only page_pool needs this */ 143 if (mem->type == MEM_TYPE_PAGE_POOL) 144 __xdp_release_frame(xdpf->data, mem); 145 } 146 147 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, 148 struct net_device *dev, u32 queue_index); 149 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq); 150 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq); 151 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq); 152 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, 153 enum xdp_mem_type type, void *allocator); 154 void xdp_rxq_info_unreg_mem_model(struct xdp_rxq_info *xdp_rxq); 155 156 /* Drivers not supporting XDP metadata can use this helper, which 157 * rejects any room expansion for metadata as a result. 158 */ 159 static __always_inline void 160 xdp_set_data_meta_invalid(struct xdp_buff *xdp) 161 { 162 xdp->data_meta = xdp->data + 1; 163 } 164 165 static __always_inline bool 166 xdp_data_meta_unsupported(const struct xdp_buff *xdp) 167 { 168 return unlikely(xdp->data_meta > xdp->data); 169 } 170 171 struct xdp_attachment_info { 172 struct bpf_prog *prog; 173 u32 flags; 174 }; 175 176 struct netdev_bpf; 177 int xdp_attachment_query(struct xdp_attachment_info *info, 178 struct netdev_bpf *bpf); 179 bool xdp_attachment_flags_ok(struct xdp_attachment_info *info, 180 struct netdev_bpf *bpf); 181 void xdp_attachment_setup(struct xdp_attachment_info *info, 182 struct netdev_bpf *bpf); 183 184 #endif /* __LINUX_NET_XDP_H__ */ 185