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_xdp_entry
  76 # define __section_xdp_entry                                            \
  77         __section(ELF_SECTION_PROG)
  78 #endif
  79
  80 #ifndef __section_cls_entry
  81 # define __section_cls_entry                                            \
  82         __section(ELF_SECTION_CLASSIFIER)
  83 #endif
  84
  85 #ifndef __section_act_entry
  86 # define __section_act_entry                                            \
  87         __section(ELF_SECTION_ACTION)
  88 #endif
  89
  90 #ifndef __section_lwt_entry
  91 # define __section_lwt_entry                                            \
  92         __section(ELF_SECTION_PROG)
  93 #endif
  94
  95 #ifndef __section_license
  96 # define __section_license                                              \
  97         __section(ELF_SECTION_LICENSE)
  98 #endif
  99
 100 #ifndef __section_maps
 101 # define __section_maps                                                 \
 102         __section(ELF_SECTION_MAPS)
 103 #endif
 104
 105 /** Declaration helper macros. */
 106
 107 #ifndef BPF_LICENSE
 108 # define BPF_LICENSE(NAME)                                              \
 109         char ____license[] __section_license = NAME
 110 #endif
 111
 112 /** Classifier helper */
 113
 114 #ifndef BPF_H_DEFAULT
 115 # define BPF_H_DEFAULT  -1
 116 #endif
 117
 118 /** BPF helper functions for tc. Individual flags are in linux/bpf.h */
 119
 120 #ifndef __BPF_FUNC
 121 # define __BPF_FUNC(NAME, ...)                                          \
 122         (* NAME)(__VA_ARGS__) __maybe_unused
 123 #endif
 124
 125 #ifndef BPF_FUNC
 126 # define BPF_FUNC(NAME, ...)                                            \
 127         __BPF_FUNC(NAME, __VA_ARGS__) = (void *) BPF_FUNC_##NAME
 128 #endif
 129
 130 /* Map access/manipulation */
 131 static void *BPF_FUNC(map_lookup_elem, void *map, const void *key);
 132 static int BPF_FUNC(map_update_elem, void *map, const void *key,
 133                     const void *value, uint32_t flags);
 134 static int BPF_FUNC(map_delete_elem, void *map, const void *key);
 135
 136 /* Time access */
 137 static uint64_t BPF_FUNC(ktime_get_ns);
 138
 139 /* Debugging */
 140
 141 /* FIXME: __attribute__ ((format(printf, 1, 3))) not possible unless
 142  * llvm bug https://llvm.org/bugs/show_bug.cgi?id=26243 gets resolved.
 143  * It would require ____fmt to be made const, which generates a reloc
 144  * entry (non-map).
 145  */
 146 static void BPF_FUNC(trace_printk, const char *fmt, int fmt_size, ...);
 147
 148 #ifndef printt
 149 # define printt(fmt, ...)                                               \
 150         ({                                                              \
 151                 char ____fmt[] = fmt;                                   \
 152                 trace_printk(____fmt, sizeof(____fmt), ##__VA_ARGS__);  \
 153         })
 154 #endif
 155
 156 /* Random numbers */
 157 static uint32_t BPF_FUNC(get_prandom_u32);
 158
 159 /* Tail calls */
 160 static void BPF_FUNC(tail_call, struct __sk_buff *skb, void *map,
 161                      uint32_t index);
 162
 163 /* System helpers */
 164 static uint32_t BPF_FUNC(get_smp_processor_id);
 165 static uint32_t BPF_FUNC(get_numa_node_id);
 166
 167 /* Packet misc meta data */
 168 static uint32_t BPF_FUNC(get_cgroup_classid, struct __sk_buff *skb);
 169 static int BPF_FUNC(skb_under_cgroup, void *map, uint32_t index);
 170
 171 static uint32_t BPF_FUNC(get_route_realm, struct __sk_buff *skb);
 172 static uint32_t BPF_FUNC(get_hash_recalc, struct __sk_buff *skb);
 173 static uint32_t BPF_FUNC(set_hash_invalid, struct __sk_buff *skb);
 174
 175 /* Packet redirection */
 176 static int BPF_FUNC(redirect, int ifindex, uint32_t flags);
 177 static int BPF_FUNC(clone_redirect, struct __sk_buff *skb, int ifindex,
 178                     uint32_t flags);
 179
 180 /* Packet manipulation */
 181 static int BPF_FUNC(skb_load_bytes, struct __sk_buff *skb, uint32_t off,
 182                     void *to, uint32_t len);
 183 static int BPF_FUNC(skb_store_bytes, struct __sk_buff *skb, uint32_t off,
 184                     const void *from, uint32_t len, uint32_t flags);
 185
 186 static int BPF_FUNC(l3_csum_replace, struct __sk_buff *skb, uint32_t off,
 187                     uint32_t from, uint32_t to, uint32_t flags);
 188 static int BPF_FUNC(l4_csum_replace, struct __sk_buff *skb, uint32_t off,
 189                     uint32_t from, uint32_t to, uint32_t flags);
 190 static int BPF_FUNC(csum_diff, const void *from, uint32_t from_size,
 191                     const void *to, uint32_t to_size, uint32_t seed);
 192 static int BPF_FUNC(csum_update, struct __sk_buff *skb, uint32_t wsum);
 193
 194 static int BPF_FUNC(skb_change_type, struct __sk_buff *skb, uint32_t type);
 195 static int BPF_FUNC(skb_change_proto, struct __sk_buff *skb, uint32_t proto,
 196                     uint32_t flags);
 197 static int BPF_FUNC(skb_change_tail, struct __sk_buff *skb, uint32_t nlen,
 198                     uint32_t flags);
 199
 200 static int BPF_FUNC(skb_pull_data, struct __sk_buff *skb, uint32_t len);
 201
 202 /* Event notification */
 203 static int __BPF_FUNC(skb_event_output, struct __sk_buff *skb, void *map,
 204                       uint64_t index, const void *data, uint32_t size) =
 205                       (void *) BPF_FUNC_perf_event_output;
 206
 207 /* Packet vlan encap/decap */
 208 static int BPF_FUNC(skb_vlan_push, struct __sk_buff *skb, uint16_t proto,
 209                     uint16_t vlan_tci);
 210 static int BPF_FUNC(skb_vlan_pop, struct __sk_buff *skb);
 211
 212 /* Packet tunnel encap/decap */
 213 static int BPF_FUNC(skb_get_tunnel_key, struct __sk_buff *skb,
 214                     struct bpf_tunnel_key *to, uint32_t size, uint32_t flags);
 215 static int BPF_FUNC(skb_set_tunnel_key, struct __sk_buff *skb,
 216                     const struct bpf_tunnel_key *from, uint32_t size,
 217                     uint32_t flags);
 218
 219 static int BPF_FUNC(skb_get_tunnel_opt, struct __sk_buff *skb,
 220                     void *to, uint32_t size);
 221 static int BPF_FUNC(skb_set_tunnel_opt, struct __sk_buff *skb,
 222                     const void *from, uint32_t size);
 223
 224 /** LLVM built-ins, mem*() routines work for constant size */
 225
 226 #ifndef lock_xadd
 227 # define lock_xadd(ptr, val)    ((void) __sync_fetch_and_add(ptr, val))
 228 #endif
 229
 230 #ifndef memset
 231 # define memset(s, c, n)        __builtin_memset((s), (c), (n))
 232 #endif
 233
 234 #ifndef memcpy
 235 # define memcpy(d, s, n)        __builtin_memcpy((d), (s), (n))
 236 #endif
 237
 238 #ifndef memmove
 239 # define memmove(d, s, n)       __builtin_memmove((d), (s), (n))
 240 #endif
 241
 242 /* FIXME: __builtin_memcmp() is not yet fully useable unless llvm bug
 243  * https://llvm.org/bugs/show_bug.cgi?id=26218 gets resolved. Also
 244  * this one would generate a reloc entry (non-map), otherwise.
 245  */
 246 #if 0
 247 #ifndef memcmp
 248 # define memcmp(a, b, n)        __builtin_memcmp((a), (b), (n))
 249 #endif
 250 #endif
 251
 252 unsigned long long load_byte(void *skb, unsigned long long off)
 253         asm ("llvm.bpf.load.byte");
 254
 255 unsigned long long load_half(void *skb, unsigned long long off)
 256         asm ("llvm.bpf.load.half");
 257
 258 unsigned long long load_word(void *skb, unsigned long long off)
 259         asm ("llvm.bpf.load.word");
 260
 261 #endif /* __BPF_API__ */