3 * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
4 * Released under terms in GPL version 2. See COPYING.
6 #ifndef __LINUX_NET_XDP_H__
7 #define __LINUX_NET_XDP_H__
10 * DOC: XDP RX-queue information
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.
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
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.
25 * The driver usage API is a register and unregister API.
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.
37 MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */
38 MEM_TYPE_PAGE_ORDER0, /* Orig XDP full page model */
44 u32 type; /* enum xdp_mem_type, but known size type */
51 struct net_device *dev;
54 struct xdp_mem_info mem;
55 } ____cacheline_aligned; /* perf critical, avoid false-sharing */
61 void *data_hard_start;
62 struct xdp_rxq_info *rxq;
70 /* Lifetime of xdp_rxq_info is limited to NAPI/enqueue time,
71 * while mem info is valid on remote CPU.
73 struct xdp_mem_info mem;
74 struct net_device *dev_rx; /* used by cpumap */
77 /* Convert xdp_buff to xdp_frame */
79 struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp)
81 struct xdp_frame *xdp_frame;
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)))
92 /* Store info in top of packet */
93 xdp_frame = xdp->data_hard_start;
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;
100 /* rxq only valid until napi_schedule ends, convert to xdp_mem_info */
101 xdp_frame->mem = xdp->rxq->mem;
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);
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);
118 /* Drivers not supporting XDP metadata can use this helper, which
119 * rejects any room expansion for metadata as a result.
121 static __always_inline void
122 xdp_set_data_meta_invalid(struct xdp_buff *xdp)
124 xdp->data_meta = xdp->data + 1;
127 static __always_inline bool
128 xdp_data_meta_unsupported(const struct xdp_buff *xdp)
130 return unlikely(xdp->data_meta > xdp->data);
133 #endif /* __LINUX_NET_XDP_H__ */