1 /* include/net/xdp.h 2 * 3 * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc. 4 * Released under terms in GPL version 2. See COPYING. 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 /* Convert xdp_buff to xdp_frame */ 95 static inline 96 struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp) 97 { 98 struct xdp_frame *xdp_frame; 99 int metasize; 100 int headroom; 101 102 /* TODO: implement clone, copy, use "native" MEM_TYPE */ 103 if (xdp->rxq->mem.type == MEM_TYPE_ZERO_COPY) 104 return NULL; 105 106 /* Assure headroom is available for storing info */ 107 headroom = xdp->data - xdp->data_hard_start; 108 metasize = xdp->data - xdp->data_meta; 109 metasize = metasize > 0 ? metasize : 0; 110 if (unlikely((headroom - metasize) < sizeof(*xdp_frame))) 111 return NULL; 112 113 /* Store info in top of packet */ 114 xdp_frame = xdp->data_hard_start; 115 116 xdp_frame->data = xdp->data; 117 xdp_frame->len = xdp->data_end - xdp->data; 118 xdp_frame->headroom = headroom - sizeof(*xdp_frame); 119 xdp_frame->metasize = metasize; 120 121 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */ 122 xdp_frame->mem = xdp->rxq->mem; 123 124 return xdp_frame; 125 } 126 127 void xdp_return_frame(struct xdp_frame *xdpf); 128 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf); 129 void xdp_return_buff(struct xdp_buff *xdp); 130 131 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, 132 struct net_device *dev, u32 queue_index); 133 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq); 134 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq); 135 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq); 136 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, 137 enum xdp_mem_type type, void *allocator); 138 139 /* Drivers not supporting XDP metadata can use this helper, which 140 * rejects any room expansion for metadata as a result. 141 */ 142 static __always_inline void 143 xdp_set_data_meta_invalid(struct xdp_buff *xdp) 144 { 145 xdp->data_meta = xdp->data + 1; 146 } 147 148 static __always_inline bool 149 xdp_data_meta_unsupported(const struct xdp_buff *xdp) 150 { 151 return unlikely(xdp->data_meta > xdp->data); 152 } 153 154 struct xdp_attachment_info { 155 struct bpf_prog *prog; 156 u32 flags; 157 }; 158 159 struct netdev_bpf; 160 int xdp_attachment_query(struct xdp_attachment_info *info, 161 struct netdev_bpf *bpf); 162 bool xdp_attachment_flags_ok(struct xdp_attachment_info *info, 163 struct netdev_bpf *bpf); 164 void xdp_attachment_setup(struct xdp_attachment_info *info, 165 struct netdev_bpf *bpf); 166 167 #endif /* __LINUX_NET_XDP_H__ */ 168