xref: /linux/include/uapi/linux/if_xdp.h (revision fe33c0fbed75dd464747c0faaedf94c7d8eb4101)
1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 /*
3  * if_xdp: XDP socket user-space interface
4  * Copyright(c) 2018 Intel Corporation.
5  *
6  * Author(s): Björn Töpel <bjorn.topel@intel.com>
7  *	      Magnus Karlsson <magnus.karlsson@intel.com>
8  */
9 
10 #ifndef _LINUX_IF_XDP_H
11 #define _LINUX_IF_XDP_H
12 
13 #include <linux/types.h>
14 
15 /* Options for the sxdp_flags field */
16 #define XDP_SHARED_UMEM	(1 << 0)
17 #define XDP_COPY	(1 << 1) /* Force copy-mode */
18 #define XDP_ZEROCOPY	(1 << 2) /* Force zero-copy mode */
19 /* If this option is set, the driver might go sleep and in that case
20  * the XDP_RING_NEED_WAKEUP flag in the fill and/or Tx rings will be
21  * set. If it is set, the application need to explicitly wake up the
22  * driver with a poll() (Rx and Tx) or sendto() (Tx only). If you are
23  * running the driver and the application on the same core, you should
24  * use this option so that the kernel will yield to the user space
25  * application.
26  */
27 #define XDP_USE_NEED_WAKEUP (1 << 3)
28 /* By setting this option, userspace application indicates that it can
29  * handle multiple descriptors per packet thus enabling AF_XDP to split
30  * multi-buffer XDP frames into multiple Rx descriptors. Without this set
31  * such frames will be dropped.
32  */
33 #define XDP_USE_SG	(1 << 4)
34 
35 /* Flags for xsk_umem_config flags */
36 #define XDP_UMEM_UNALIGNED_CHUNK_FLAG	(1 << 0)
37 
38 /* Force checksum calculation in software. Can be used for testing or
39  * working around potential HW issues. This option causes performance
40  * degradation and only works in XDP_COPY mode.
41  */
42 #define XDP_UMEM_TX_SW_CSUM		(1 << 1)
43 
44 struct sockaddr_xdp {
45 	__u16 sxdp_family;
46 	__u16 sxdp_flags;
47 	__u32 sxdp_ifindex;
48 	__u32 sxdp_queue_id;
49 	__u32 sxdp_shared_umem_fd;
50 };
51 
52 /* XDP_RING flags */
53 #define XDP_RING_NEED_WAKEUP (1 << 0)
54 
55 struct xdp_ring_offset {
56 	__u64 producer;
57 	__u64 consumer;
58 	__u64 desc;
59 	__u64 flags;
60 };
61 
62 struct xdp_mmap_offsets {
63 	struct xdp_ring_offset rx;
64 	struct xdp_ring_offset tx;
65 	struct xdp_ring_offset fr; /* Fill */
66 	struct xdp_ring_offset cr; /* Completion */
67 };
68 
69 /* XDP socket options */
70 #define XDP_MMAP_OFFSETS		1
71 #define XDP_RX_RING			2
72 #define XDP_TX_RING			3
73 #define XDP_UMEM_REG			4
74 #define XDP_UMEM_FILL_RING		5
75 #define XDP_UMEM_COMPLETION_RING	6
76 #define XDP_STATISTICS			7
77 #define XDP_OPTIONS			8
78 
79 struct xdp_umem_reg {
80 	__u64 addr; /* Start of packet data area */
81 	__u64 len; /* Length of packet data area */
82 	__u32 chunk_size;
83 	__u32 headroom;
84 	__u32 flags;
85 	__u32 tx_metadata_len;
86 };
87 
88 struct xdp_statistics {
89 	__u64 rx_dropped; /* Dropped for other reasons */
90 	__u64 rx_invalid_descs; /* Dropped due to invalid descriptor */
91 	__u64 tx_invalid_descs; /* Dropped due to invalid descriptor */
92 	__u64 rx_ring_full; /* Dropped due to rx ring being full */
93 	__u64 rx_fill_ring_empty_descs; /* Failed to retrieve item from fill ring */
94 	__u64 tx_ring_empty_descs; /* Failed to retrieve item from tx ring */
95 };
96 
97 struct xdp_options {
98 	__u32 flags;
99 };
100 
101 /* Flags for the flags field of struct xdp_options */
102 #define XDP_OPTIONS_ZEROCOPY (1 << 0)
103 
104 /* Pgoff for mmaping the rings */
105 #define XDP_PGOFF_RX_RING			  0
106 #define XDP_PGOFF_TX_RING		 0x80000000
107 #define XDP_UMEM_PGOFF_FILL_RING	0x100000000ULL
108 #define XDP_UMEM_PGOFF_COMPLETION_RING	0x180000000ULL
109 
110 /* Masks for unaligned chunks mode */
111 #define XSK_UNALIGNED_BUF_OFFSET_SHIFT 48
112 #define XSK_UNALIGNED_BUF_ADDR_MASK \
113 	((1ULL << XSK_UNALIGNED_BUF_OFFSET_SHIFT) - 1)
114 
115 /* Request transmit timestamp. Upon completion, put it into tx_timestamp
116  * field of struct xsk_tx_metadata.
117  */
118 #define XDP_TXMD_FLAGS_TIMESTAMP		(1 << 0)
119 
120 /* Request transmit checksum offload. Checksum start position and offset
121  * are communicated via csum_start and csum_offset fields of struct
122  * xsk_tx_metadata.
123  */
124 #define XDP_TXMD_FLAGS_CHECKSUM			(1 << 1)
125 
126 /* AF_XDP offloads request. 'request' union member is consumed by the driver
127  * when the packet is being transmitted. 'completion' union member is
128  * filled by the driver when the transmit completion arrives.
129  */
130 struct xsk_tx_metadata {
131 	__u64 flags;
132 
133 	union {
134 		struct {
135 			/* XDP_TXMD_FLAGS_CHECKSUM */
136 
137 			/* Offset from desc->addr where checksumming should start. */
138 			__u16 csum_start;
139 			/* Offset from csum_start where checksum should be stored. */
140 			__u16 csum_offset;
141 		} request;
142 
143 		struct {
144 			/* XDP_TXMD_FLAGS_TIMESTAMP */
145 			__u64 tx_timestamp;
146 		} completion;
147 	};
148 };
149 
150 /* Rx/Tx descriptor */
151 struct xdp_desc {
152 	__u64 addr;
153 	__u32 len;
154 	__u32 options;
155 };
156 
157 /* UMEM descriptor is __u64 */
158 
159 /* Flag indicating that the packet continues with the buffer pointed out by the
160  * next frame in the ring. The end of the packet is signalled by setting this
161  * bit to zero. For single buffer packets, every descriptor has 'options' set
162  * to 0 and this maintains backward compatibility.
163  */
164 #define XDP_PKT_CONTD (1 << 0)
165 
166 /* TX packet carries valid metadata. */
167 #define XDP_TX_METADATA (1 << 1)
168 
169 #endif /* _LINUX_IF_XDP_H */
170