include/bpf_api.h

   1 #ifndef __BPF_API__
   2 #define __BPF_API__
   3
   4 /* Note:
   5  *
   6  * This file can be included into eBPF kernel programs. It contains
   7  * a couple of useful helper functions, map/section ABI (bpf_elf.h),
   8  * misc macros and some eBPF specific LLVM built-ins.
   9  */
  10
  11 #include <stdint.h>
  12
  13 #include <linux/pkt_cls.h>
  14 #include <linux/bpf.h>
  15 #include <linux/filter.h>
  16
  17 #include <asm/byteorder.h>
  18
  19 #include "bpf_elf.h"
  20
  21 /** Misc macros. */
  22
  23 #ifndef __stringify
  24 # define __stringify(X)         #X
  25 #endif
  26
  27 #ifndef __maybe_unused
  28 # define __maybe_unused         __attribute__((__unused__))
  29 #endif
  30
  31 #ifndef offsetof
  32 # define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER)
  33 #endif
  34
  35 #ifndef likely
  36 # define likely(X)              __builtin_expect(!!(X), 1)
  37 #endif
  38
  39 #ifndef unlikely
  40 # define unlikely(X)            __builtin_expect(!!(X), 0)
  41 #endif
  42
  43 #ifndef htons
  44 # define htons(X)               __constant_htons((X))
  45 #endif
  46
  47 #ifndef ntohs
  48 # define ntohs(X)               __constant_ntohs((X))
  49 #endif
  50
  51 #ifndef htonl
  52 # define htonl(X)               __constant_htonl((X))
  53 #endif
  54
  55 #ifndef ntohl
  56 # define ntohl(X)               __constant_ntohl((X))
  57 #endif
  58
  59 /** Section helper macros. */
  60
  61 #ifndef __section
  62 # define __section(NAME)                                                \
  63         __attribute__((section(NAME), used))
  64 #endif
  65
  66 #ifndef __section_tail
  67 # define __section_tail(ID, KEY)                                        \
  68         __section(__stringify(ID) "/" __stringify(KEY))
  69 #endif
  70
  71 #ifndef __section_cls_entry
  72 # define __section_cls_entry                                            \
  73         __section(ELF_SECTION_CLASSIFIER)
  74 #endif
  75
  76 #ifndef __section_act_entry
  77 # define __section_act_entry                                            \
  78         __section(ELF_SECTION_ACTION)
  79 #endif
  80
  81 #ifndef __section_license
  82 # define __section_license                                              \
  83         __section(ELF_SECTION_LICENSE)
  84 #endif
  85
  86 #ifndef __section_maps
  87 # define __section_maps                                                 \
  88         __section(ELF_SECTION_MAPS)
  89 #endif
  90
  91 /** Declaration helper macros. */
  92
  93 #ifndef BPF_LICENSE
  94 # define BPF_LICENSE(NAME)                                              \
  95         char ____license[] __section_license = NAME
  96 #endif
  97
  98 #ifndef __BPF_MAP
  99 # define __BPF_MAP(NAME, TYPE, ID, SIZE_KEY, SIZE_VALUE, PIN, MAX_ELEM) \
 100         struct bpf_elf_map __section_maps NAME = {                      \
 101                 .type           = (TYPE),                               \
 102                 .id             = (ID),                                 \
 103                 .size_key       = (SIZE_KEY),                           \
 104                 .size_value     = (SIZE_VALUE),                         \
 105                 .pinning        = (PIN),                                \
 106                 .max_elem       = (MAX_ELEM),                           \
 107         }
 108 #endif
 109
 110 #ifndef BPF_HASH
 111 # define BPF_HASH(NAME, ID, SIZE_KEY, SIZE_VALUE, PIN, MAX_ELEM)        \
 112         __BPF_MAP(NAME, BPF_MAP_TYPE_HASH, ID, SIZE_KEY, SIZE_VALUE,    \
 113                   PIN, MAX_ELEM)
 114 #endif
 115
 116 #ifndef BPF_ARRAY
 117 # define BPF_ARRAY(NAME, ID, SIZE_VALUE, PIN, MAX_ELEM)                 \
 118         __BPF_MAP(NAME, BPF_MAP_TYPE_ARRAY, ID, sizeof(uint32_t),       \
 119                   SIZE_VALUE, PIN, MAX_ELEM)
 120 #endif
 121
 122 #ifndef BPF_ARRAY2
 123 # define BPF_ARRAY2(NAME, ID, PIN, MAX_ELEM)                            \
 124         BPF_ARRAY(NAME, ID, sizeof(uint16_t), PIN, MAX_ELEM)
 125 #endif
 126
 127 #ifndef BPF_ARRAY4
 128 # define BPF_ARRAY4(NAME, ID, PIN, MAX_ELEM)                            \
 129         BPF_ARRAY(NAME, ID, sizeof(uint32_t), PIN, MAX_ELEM)
 130 #endif
 131
 132 #ifndef BPF_ARRAY8
 133 # define BPF_ARRAY8(NAME, ID, PIN, MAX_ELEM)                            \
 134         BPF_ARRAY(NAME, ID, sizeof(uint64_t), PIN, MAX_ELEM)
 135 #endif
 136
 137 #ifndef BPF_PROG_ARRAY
 138 # define BPF_PROG_ARRAY(NAME, ID, PIN, MAX_ELEM)                        \
 139         __BPF_MAP(NAME, BPF_MAP_TYPE_PROG_ARRAY, ID, sizeof(uint32_t),  \
 140                   sizeof(uint32_t), PIN, MAX_ELEM)
 141 #endif
 142
 143 /** Classifier helper */
 144
 145 #ifndef BPF_H_DEFAULT
 146 # define BPF_H_DEFAULT  -1
 147 #endif
 148
 149 /** BPF helper functions for tc. */
 150
 151 #ifndef BPF_FUNC
 152 # define BPF_FUNC(NAME, ...)                                            \
 153         (* NAME)(__VA_ARGS__) __maybe_unused = (void *) BPF_FUNC_##NAME
 154 #endif
 155
 156 /* Map access/manipulation */
 157 static void *BPF_FUNC(map_lookup_elem, void *map, const void *key);
 158 static int BPF_FUNC(map_update_elem, void *map, const void *key,
 159                     const void *value, uint32_t flags);
 160 static int BPF_FUNC(map_delete_elem, void *map, const void *key);
 161
 162 /* Time access */
 163 static uint64_t BPF_FUNC(ktime_get_ns);
 164
 165 /* Debugging */
 166 static void BPF_FUNC(trace_printk, const char *fmt, int fmt_size, ...);
 167
 168 /* Random numbers */
 169 static uint32_t BPF_FUNC(get_prandom_u32);
 170
 171 /* Tail calls */
 172 static void BPF_FUNC(tail_call, struct __sk_buff *skb, void *map,
 173                      uint32_t index);
 174
 175 /* System helpers */
 176 static uint32_t BPF_FUNC(get_smp_processor_id);
 177
 178 /* Packet misc meta data */
 179 static uint32_t BPF_FUNC(get_cgroup_classid, struct __sk_buff *skb);
 180 static uint32_t BPF_FUNC(get_route_realm, struct __sk_buff *skb);
 181
 182 /* Packet redirection */
 183 static int BPF_FUNC(redirect, int ifindex, uint32_t flags);
 184 static int BPF_FUNC(clone_redirect, struct __sk_buff *skb, int ifindex,
 185                     uint32_t flags);
 186
 187 /* Packet manipulation */
 188 #define BPF_PSEUDO_HDR                  0x10
 189 #define BPF_HAS_PSEUDO_HDR(flags)       ((flags) & BPF_PSEUDO_HDR)
 190 #define BPF_HDR_FIELD_SIZE(flags)       ((flags) & 0x0f)
 191
 192 static int BPF_FUNC(skb_store_bytes, struct __sk_buff *skb, uint32_t off,
 193                     void *from, uint32_t len, uint32_t flags);
 194 static int BPF_FUNC(l3_csum_replace, struct __sk_buff *skb, uint32_t off,
 195                     uint32_t from, uint32_t to, uint32_t flags);
 196 static int BPF_FUNC(l4_csum_replace, struct __sk_buff *skb, uint32_t off,
 197                     uint32_t from, uint32_t to, uint32_t flags);
 198
 199 /* Packet vlan encap/decap */
 200 static int BPF_FUNC(skb_vlan_push, struct __sk_buff *skb, uint16_t proto,
 201                     uint16_t vlan_tci);
 202 static int BPF_FUNC(skb_vlan_pop, struct __sk_buff *skb);
 203
 204 /* Packet tunnel encap/decap */
 205 static int BPF_FUNC(skb_get_tunnel_key, struct __sk_buff *skb,
 206                     struct bpf_tunnel_key *to, uint32_t size, uint32_t flags);
 207 static int BPF_FUNC(skb_set_tunnel_key, struct __sk_buff *skb,
 208                     struct bpf_tunnel_key *from, uint32_t size, uint32_t flags);
 209
 210 /** LLVM built-ins */
 211
 212 #ifndef lock_xadd
 213 # define lock_xadd(ptr, val)    ((void) __sync_fetch_and_add(ptr, val))
 214 #endif
 215
 216 unsigned long long load_byte(void *skb, unsigned long long off)
 217         asm ("llvm.bpf.load.byte");
 218
 219 unsigned long long load_half(void *skb, unsigned long long off)
 220         asm ("llvm.bpf.load.half");
 221
 222 unsigned long long load_word(void *skb, unsigned long long off)
 223         asm ("llvm.bpf.load.word");
 224
 225 #endif /* __BPF_API__ */