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_MAX, 41 }; 42 43 /* XDP flags for ndo_xdp_xmit */ 44 #define XDP_XMIT_FLAGS_NONE 0U 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 xdp_rxq_info { 56 struct net_device *dev; 57 u32 queue_index; 58 u32 reg_state; 59 struct xdp_mem_info mem; 60 } ____cacheline_aligned; /* perf critical, avoid false-sharing */ 61 62 struct xdp_buff { 63 void *data; 64 void *data_end; 65 void *data_meta; 66 void *data_hard_start; 67 struct xdp_rxq_info *rxq; 68 }; 69 70 struct xdp_frame { 71 void *data; 72 u16 len; 73 u16 headroom; 74 u16 metasize; 75 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time, 76 * while mem info is valid on remote CPU. 77 */ 78 struct xdp_mem_info mem; 79 struct net_device *dev_rx; /* used by cpumap */ 80 }; 81 82 /* Convert xdp_buff to xdp_frame */ 83 static inline 84 struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp) 85 { 86 struct xdp_frame *xdp_frame; 87 int metasize; 88 int headroom; 89 90 /* Assure headroom is available for storing info */ 91 headroom = xdp->data - xdp->data_hard_start; 92 metasize = xdp->data - xdp->data_meta; 93 metasize = metasize > 0 ? metasize : 0; 94 if (unlikely((headroom - metasize) < sizeof(*xdp_frame))) 95 return NULL; 96 97 /* Store info in top of packet */ 98 xdp_frame = xdp->data_hard_start; 99 100 xdp_frame->data = xdp->data; 101 xdp_frame->len = xdp->data_end - xdp->data; 102 xdp_frame->headroom = headroom - sizeof(*xdp_frame); 103 xdp_frame->metasize = metasize; 104 105 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */ 106 xdp_frame->mem = xdp->rxq->mem; 107 108 return xdp_frame; 109 } 110 111 void xdp_return_frame(struct xdp_frame *xdpf); 112 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf); 113 void xdp_return_buff(struct xdp_buff *xdp); 114 115 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, 116 struct net_device *dev, u32 queue_index); 117 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq); 118 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq); 119 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq); 120 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, 121 enum xdp_mem_type type, void *allocator); 122 123 /* Drivers not supporting XDP metadata can use this helper, which 124 * rejects any room expansion for metadata as a result. 125 */ 126 static __always_inline void 127 xdp_set_data_meta_invalid(struct xdp_buff *xdp) 128 { 129 xdp->data_meta = xdp->data + 1; 130 } 131 132 static __always_inline bool 133 xdp_data_meta_unsupported(const struct xdp_buff *xdp) 134 { 135 return unlikely(xdp->data_meta > xdp->data); 136 } 137 138 #endif /* __LINUX_NET_XDP_H__ */ 139