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 struct xdp_mem_info { 44 u32 type; /* enum xdp_mem_type, but known size type */ 45 u32 id; 46 }; 47 48 struct page_pool; 49 50 struct xdp_rxq_info { 51 struct net_device *dev; 52 u32 queue_index; 53 u32 reg_state; 54 struct xdp_mem_info mem; 55 } ____cacheline_aligned; /* perf critical, avoid false-sharing */ 56 57 struct xdp_buff { 58 void *data; 59 void *data_end; 60 void *data_meta; 61 void *data_hard_start; 62 struct xdp_rxq_info *rxq; 63 }; 64 65 struct xdp_frame { 66 void *data; 67 u16 len; 68 u16 headroom; 69 u16 metasize; 70 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time, 71 * while mem info is valid on remote CPU. 72 */ 73 struct xdp_mem_info mem; 74 struct net_device *dev_rx; /* used by cpumap */ 75 }; 76 77 /* Convert xdp_buff to xdp_frame */ 78 static inline 79 struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp) 80 { 81 struct xdp_frame *xdp_frame; 82 int metasize; 83 int headroom; 84 85 /* Assure headroom is available for storing info */ 86 headroom = xdp->data - xdp->data_hard_start; 87 metasize = xdp->data - xdp->data_meta; 88 metasize = metasize > 0 ? metasize : 0; 89 if (unlikely((headroom - metasize) < sizeof(*xdp_frame))) 90 return NULL; 91 92 /* Store info in top of packet */ 93 xdp_frame = xdp->data_hard_start; 94 95 xdp_frame->data = xdp->data; 96 xdp_frame->len = xdp->data_end - xdp->data; 97 xdp_frame->headroom = headroom - sizeof(*xdp_frame); 98 xdp_frame->metasize = metasize; 99 100 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */ 101 xdp_frame->mem = xdp->rxq->mem; 102 103 return xdp_frame; 104 } 105 106 void xdp_return_frame(struct xdp_frame *xdpf); 107 void xdp_return_frame_rx_napi(struct xdp_frame *xdpf); 108 void xdp_return_buff(struct xdp_buff *xdp); 109 110 int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq, 111 struct net_device *dev, u32 queue_index); 112 void xdp_rxq_info_unreg(struct xdp_rxq_info *xdp_rxq); 113 void xdp_rxq_info_unused(struct xdp_rxq_info *xdp_rxq); 114 bool xdp_rxq_info_is_reg(struct xdp_rxq_info *xdp_rxq); 115 int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, 116 enum xdp_mem_type type, void *allocator); 117 118 /* Drivers not supporting XDP metadata can use this helper, which 119 * rejects any room expansion for metadata as a result. 120 */ 121 static __always_inline void 122 xdp_set_data_meta_invalid(struct xdp_buff *xdp) 123 { 124 xdp->data_meta = xdp->data + 1; 125 } 126 127 static __always_inline bool 128 xdp_data_meta_unsupported(const struct xdp_buff *xdp) 129 { 130 return unlikely(xdp->data_meta > xdp->data); 131 } 132 133 #endif /* __LINUX_NET_XDP_H__ */ 134