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 #ifndef __inline__
  60 # define __inline__             __attribute__((always_inline))
  61 #endif
  62
  63 /** Section helper macros. */
  64
  65 #ifndef __section
  66 # define __section(NAME)                                                \
  67         __attribute__((section(NAME), used))
  68 #endif
  69
  70 #ifndef __section_tail
  71 # define __section_tail(ID, KEY)                                        \
  72         __section(__stringify(ID) "/" __stringify(KEY))
  73 #endif
  74
  75 #ifndef __section_cls_entry
  76 # define __section_cls_entry                                            \
  77         __section(ELF_SECTION_CLASSIFIER)
  78 #endif
  79
  80 #ifndef __section_act_entry
  81 # define __section_act_entry                                            \
  82         __section(ELF_SECTION_ACTION)
  83 #endif
  84
  85 #ifndef __section_license
  86 # define __section_license                                              \
  87         __section(ELF_SECTION_LICENSE)
  88 #endif
  89
  90 #ifndef __section_maps
  91 # define __section_maps                                                 \
  92         __section(ELF_SECTION_MAPS)
  93 #endif
  94
  95 /** Declaration helper macros. */
  96
  97 #ifndef BPF_LICENSE
  98 # define BPF_LICENSE(NAME)                                              \
  99         char ____license[] __section_license = NAME
 100 #endif
 101
 102 /** Classifier helper */
 103
 104 #ifndef BPF_H_DEFAULT
 105 # define BPF_H_DEFAULT  -1
 106 #endif
 107
 108 /** BPF helper functions for tc. Individual flags are in linux/bpf.h */
 109
 110 #ifndef __BPF_FUNC
 111 # define __BPF_FUNC(NAME, ...)                                          \
 112         (* NAME)(__VA_ARGS__) __maybe_unused
 113 #endif
 114
 115 #ifndef BPF_FUNC
 116 # define BPF_FUNC(NAME, ...)                                            \
 117         __BPF_FUNC(NAME, __VA_ARGS__) = (void *) BPF_FUNC_##NAME
 118 #endif
 119
 120 /* Map access/manipulation */
 121 static void *BPF_FUNC(map_lookup_elem, void *map, const void *key);
 122 static int BPF_FUNC(map_update_elem, void *map, const void *key,
 123                     const void *value, uint32_t flags);
 124 static int BPF_FUNC(map_delete_elem, void *map, const void *key);
 125
 126 /* Time access */
 127 static uint64_t BPF_FUNC(ktime_get_ns);
 128
 129 /* Debugging */
 130
 131 /* FIXME: __attribute__ ((format(printf, 1, 3))) not possible unless
 132  * llvm bug https://llvm.org/bugs/show_bug.cgi?id=26243 gets resolved.
 133  * It would require ____fmt to be made const, which generates a reloc
 134  * entry (non-map).
 135  */
 136 static void BPF_FUNC(trace_printk, const char *fmt, int fmt_size, ...);
 137
 138 #ifndef printt
 139 # define printt(fmt, ...)                                               \
 140         ({                                                              \
 141                 char ____fmt[] = fmt;                                   \
 142                 trace_printk(____fmt, sizeof(____fmt), ##__VA_ARGS__);  \
 143         })
 144 #endif
 145
 146 /* Random numbers */
 147 static uint32_t BPF_FUNC(get_prandom_u32);
 148
 149 /* Tail calls */
 150 static void BPF_FUNC(tail_call, struct __sk_buff *skb, void *map,
 151                      uint32_t index);
 152
 153 /* System helpers */
 154 static uint32_t BPF_FUNC(get_smp_processor_id);
 155 static uint32_t BPF_FUNC(get_numa_node_id);
 156
 157 /* Packet misc meta data */
 158 static uint32_t BPF_FUNC(get_cgroup_classid, struct __sk_buff *skb);
 159 static int BPF_FUNC(skb_under_cgroup, void *map, uint32_t index);
 160
 161 static uint32_t BPF_FUNC(get_route_realm, struct __sk_buff *skb);
 162 static uint32_t BPF_FUNC(get_hash_recalc, struct __sk_buff *skb);
 163 static uint32_t BPF_FUNC(set_hash_invalid, struct __sk_buff *skb);
 164
 165 /* Packet redirection */
 166 static int BPF_FUNC(redirect, int ifindex, uint32_t flags);
 167 static int BPF_FUNC(clone_redirect, struct __sk_buff *skb, int ifindex,
 168                     uint32_t flags);
 169
 170 /* Packet manipulation */
 171 static int BPF_FUNC(skb_load_bytes, struct __sk_buff *skb, uint32_t off,
 172                     void *to, uint32_t len);
 173 static int BPF_FUNC(skb_store_bytes, struct __sk_buff *skb, uint32_t off,
 174                     const void *from, uint32_t len, uint32_t flags);
 175
 176 static int BPF_FUNC(l3_csum_replace, struct __sk_buff *skb, uint32_t off,
 177                     uint32_t from, uint32_t to, uint32_t flags);
 178 static int BPF_FUNC(l4_csum_replace, struct __sk_buff *skb, uint32_t off,
 179                     uint32_t from, uint32_t to, uint32_t flags);
 180 static int BPF_FUNC(csum_diff, const void *from, uint32_t from_size,
 181                     const void *to, uint32_t to_size, uint32_t seed);
 182 static int BPF_FUNC(csum_update, struct __sk_buff *skb, uint32_t wsum);
 183
 184 static int BPF_FUNC(skb_change_type, struct __sk_buff *skb, uint32_t type);
 185 static int BPF_FUNC(skb_change_proto, struct __sk_buff *skb, uint32_t proto,
 186                     uint32_t flags);
 187 static int BPF_FUNC(skb_change_tail, struct __sk_buff *skb, uint32_t nlen,
 188                     uint32_t flags);
 189
 190 static int BPF_FUNC(skb_pull_data, struct __sk_buff *skb, uint32_t len);
 191
 192 /* Event notification */
 193 static int __BPF_FUNC(skb_event_output, struct __sk_buff *skb, void *map,
 194                       uint64_t index, const void *data, uint32_t size) =
 195                       (void *) BPF_FUNC_perf_event_output;
 196
 197 /* Packet vlan encap/decap */
 198 static int BPF_FUNC(skb_vlan_push, struct __sk_buff *skb, uint16_t proto,
 199                     uint16_t vlan_tci);
 200 static int BPF_FUNC(skb_vlan_pop, struct __sk_buff *skb);
 201
 202 /* Packet tunnel encap/decap */
 203 static int BPF_FUNC(skb_get_tunnel_key, struct __sk_buff *skb,
 204                     struct bpf_tunnel_key *to, uint32_t size, uint32_t flags);
 205 static int BPF_FUNC(skb_set_tunnel_key, struct __sk_buff *skb,
 206                     const struct bpf_tunnel_key *from, uint32_t size,
 207                     uint32_t flags);
 208
 209 static int BPF_FUNC(skb_get_tunnel_opt, struct __sk_buff *skb,
 210                     void *to, uint32_t size);
 211 static int BPF_FUNC(skb_set_tunnel_opt, struct __sk_buff *skb,
 212                     const void *from, uint32_t size);
 213
 214 /** LLVM built-ins, mem*() routines work for constant size */
 215
 216 #ifndef lock_xadd
 217 # define lock_xadd(ptr, val)    ((void) __sync_fetch_and_add(ptr, val))
 218 #endif
 219
 220 #ifndef memset
 221 # define memset(s, c, n)        __builtin_memset((s), (c), (n))
 222 #endif
 223
 224 #ifndef memcpy
 225 # define memcpy(d, s, n)        __builtin_memcpy((d), (s), (n))
 226 #endif
 227
 228 #ifndef memmove
 229 # define memmove(d, s, n)       __builtin_memmove((d), (s), (n))
 230 #endif
 231
 232 /* FIXME: __builtin_memcmp() is not yet fully useable unless llvm bug
 233  * https://llvm.org/bugs/show_bug.cgi?id=26218 gets resolved. Also
 234  * this one would generate a reloc entry (non-map), otherwise.
 235  */
 236 #if 0
 237 #ifndef memcmp
 238 # define memcmp(a, b, n)        __builtin_memcmp((a), (b), (n))
 239 #endif
 240 #endif
 241
 242 unsigned long long load_byte(void *skb, unsigned long long off)
 243         asm ("llvm.bpf.load.byte");
 244
 245 unsigned long long load_half(void *skb, unsigned long long off)
 246         asm ("llvm.bpf.load.half");
 247
 248 unsigned long long load_word(void *skb, unsigned long long off)
 249         asm ("llvm.bpf.load.word");
 250
 251 #endif /* __BPF_API__ */