xref: /openbmc/linux/samples/bpf/xdp_sample.bpf.h (revision 63705da3)
1 // SPDX-License-Identifier: GPL-2.0
2 #ifndef _XDP_SAMPLE_BPF_H
3 #define _XDP_SAMPLE_BPF_H
4 
5 #include "vmlinux.h"
6 #include <bpf/bpf_tracing.h>
7 #include <bpf/bpf_core_read.h>
8 #include <bpf/bpf_helpers.h>
9 
10 #include "xdp_sample_shared.h"
11 
12 #define ETH_ALEN 6
13 #define ETH_P_802_3_MIN 0x0600
14 #define ETH_P_8021Q 0x8100
15 #define ETH_P_8021AD 0x88A8
16 #define ETH_P_IP 0x0800
17 #define ETH_P_IPV6 0x86DD
18 #define ETH_P_ARP 0x0806
19 #define IPPROTO_ICMPV6 58
20 
21 #define EINVAL 22
22 #define ENETDOWN 100
23 #define EMSGSIZE 90
24 #define EOPNOTSUPP 95
25 #define ENOSPC 28
26 
27 typedef struct {
28 	__uint(type, BPF_MAP_TYPE_ARRAY);
29 	__uint(map_flags, BPF_F_MMAPABLE);
30 	__type(key, unsigned int);
31 	__type(value, struct datarec);
32 } array_map;
33 
34 extern array_map rx_cnt;
35 extern const volatile int nr_cpus;
36 
37 enum {
38 	XDP_REDIRECT_SUCCESS = 0,
39 	XDP_REDIRECT_ERROR = 1
40 };
41 
42 static __always_inline void swap_src_dst_mac(void *data)
43 {
44 	unsigned short *p = data;
45 	unsigned short dst[3];
46 
47 	dst[0] = p[0];
48 	dst[1] = p[1];
49 	dst[2] = p[2];
50 	p[0] = p[3];
51 	p[1] = p[4];
52 	p[2] = p[5];
53 	p[3] = dst[0];
54 	p[4] = dst[1];
55 	p[5] = dst[2];
56 }
57 
58 #if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && \
59 	__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
60 #define bpf_ntohs(x)		__builtin_bswap16(x)
61 #define bpf_htons(x)		__builtin_bswap16(x)
62 #elif defined(__BYTE_ORDER__) && defined(__ORDER_BIG_ENDIAN__) && \
63 	__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
64 #define bpf_ntohs(x)		(x)
65 #define bpf_htons(x)		(x)
66 #else
67 # error "Endianness detection needs to be set up for your compiler?!"
68 #endif
69 
70 /*
71  * Note: including linux/compiler.h or linux/kernel.h for the macros below
72  * conflicts with vmlinux.h include in BPF files, so we define them here.
73  *
74  * Following functions are taken from kernel sources and
75  * break aliasing rules in their original form.
76  *
77  * While kernel is compiled with -fno-strict-aliasing,
78  * perf uses -Wstrict-aliasing=3 which makes build fail
79  * under gcc 4.4.
80  *
81  * Using extra __may_alias__ type to allow aliasing
82  * in this case.
83  */
84 typedef __u8  __attribute__((__may_alias__))  __u8_alias_t;
85 typedef __u16 __attribute__((__may_alias__)) __u16_alias_t;
86 typedef __u32 __attribute__((__may_alias__)) __u32_alias_t;
87 typedef __u64 __attribute__((__may_alias__)) __u64_alias_t;
88 
89 static __always_inline void __read_once_size(const volatile void *p, void *res, int size)
90 {
91 	switch (size) {
92 	case 1: *(__u8_alias_t  *) res = *(volatile __u8_alias_t  *) p; break;
93 	case 2: *(__u16_alias_t *) res = *(volatile __u16_alias_t *) p; break;
94 	case 4: *(__u32_alias_t *) res = *(volatile __u32_alias_t *) p; break;
95 	case 8: *(__u64_alias_t *) res = *(volatile __u64_alias_t *) p; break;
96 	default:
97 		asm volatile ("" : : : "memory");
98 		__builtin_memcpy((void *)res, (const void *)p, size);
99 		asm volatile ("" : : : "memory");
100 	}
101 }
102 
103 static __always_inline void __write_once_size(volatile void *p, void *res, int size)
104 {
105 	switch (size) {
106 	case 1: *(volatile  __u8_alias_t *) p = *(__u8_alias_t  *) res; break;
107 	case 2: *(volatile __u16_alias_t *) p = *(__u16_alias_t *) res; break;
108 	case 4: *(volatile __u32_alias_t *) p = *(__u32_alias_t *) res; break;
109 	case 8: *(volatile __u64_alias_t *) p = *(__u64_alias_t *) res; break;
110 	default:
111 		asm volatile ("" : : : "memory");
112 		__builtin_memcpy((void *)p, (const void *)res, size);
113 		asm volatile ("" : : : "memory");
114 	}
115 }
116 
117 #define READ_ONCE(x)					\
118 ({							\
119 	union { typeof(x) __val; char __c[1]; } __u =	\
120 		{ .__c = { 0 } };			\
121 	__read_once_size(&(x), __u.__c, sizeof(x));	\
122 	__u.__val;					\
123 })
124 
125 #define WRITE_ONCE(x, val)				\
126 ({							\
127 	union { typeof(x) __val; char __c[1]; } __u =	\
128 		{ .__val = (val) }; 			\
129 	__write_once_size(&(x), __u.__c, sizeof(x));	\
130 	__u.__val;					\
131 })
132 
133 /* Add a value using relaxed read and relaxed write. Less expensive than
134  * fetch_add when there is no write concurrency.
135  */
136 #define NO_TEAR_ADD(x, val) WRITE_ONCE((x), READ_ONCE(x) + (val))
137 #define NO_TEAR_INC(x) NO_TEAR_ADD((x), 1)
138 
139 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
140 
141 #endif
142