include/bpf_api.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __BPF_API__
   3 #define __BPF_API__
   4
   5 /* Note:
   6  *
   7  * This file can be included into eBPF kernel programs. It contains
   8  * a couple of useful helper functions, map/section ABI (bpf_elf.h),
   9  * misc macros and some eBPF specific LLVM built-ins.
  10  */
  11
  12 #include <stdint.h>
  13
  14 #include <linux/pkt_cls.h>
  15 #include <linux/bpf.h>
  16 #include <linux/filter.h>
  17
  18 #include <asm/byteorder.h>
  19
  20 #include "bpf_elf.h"
  21
  22 /** libbpf pin type. */
  23 enum libbpf_pin_type {
  24         LIBBPF_PIN_NONE,
  25         /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */
  26         LIBBPF_PIN_BY_NAME,
  27 };
  28
  29 /** Type helper macros. */
  30
  31 #define __uint(name, val) int (*name)[val]
  32 #define __type(name, val) typeof(val) *name
  33 #define __array(name, val) typeof(val) *name[]
  34
  35 /** Misc macros. */
  36
  37 #ifndef __stringify
  38 # define __stringify(X)         #X
  39 #endif
  40
  41 #ifndef __maybe_unused
  42 # define __maybe_unused         __attribute__((__unused__))
  43 #endif
  44
  45 #ifndef offsetof
  46 # define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER)
  47 #endif
  48
  49 #ifndef likely
  50 # define likely(X)              __builtin_expect(!!(X), 1)
  51 #endif
  52
  53 #ifndef unlikely
  54 # define unlikely(X)            __builtin_expect(!!(X), 0)
  55 #endif
  56
  57 #ifndef htons
  58 # define htons(X)               __constant_htons((X))
  59 #endif
  60
  61 #ifndef ntohs
  62 # define ntohs(X)               __constant_ntohs((X))
  63 #endif
  64
  65 #ifndef htonl
  66 # define htonl(X)               __constant_htonl((X))
  67 #endif
  68
  69 #ifndef ntohl
  70 # define ntohl(X)               __constant_ntohl((X))
  71 #endif
  72
  73 #ifndef __inline__
  74 # define __inline__             __attribute__((always_inline))
  75 #endif
  76
  77 /** Section helper macros. */
  78
  79 #ifndef __section
  80 # define __section(NAME)                                                \
  81         __attribute__((section(NAME), used))
  82 #endif
  83
  84 #ifndef __section_tail
  85 # define __section_tail(ID, KEY)                                        \
  86         __section(__stringify(ID) "/" __stringify(KEY))
  87 #endif
  88
  89 #ifndef __section_xdp_entry
  90 # define __section_xdp_entry                                            \
  91         __section(ELF_SECTION_PROG)
  92 #endif
  93
  94 #ifndef __section_cls_entry
  95 # define __section_cls_entry                                            \
  96         __section(ELF_SECTION_CLASSIFIER)
  97 #endif
  98
  99 #ifndef __section_act_entry
 100 # define __section_act_entry                                            \
 101         __section(ELF_SECTION_ACTION)
 102 #endif
 103
 104 #ifndef __section_lwt_entry
 105 # define __section_lwt_entry                                            \
 106         __section(ELF_SECTION_PROG)
 107 #endif
 108
 109 #ifndef __section_license
 110 # define __section_license                                              \
 111         __section(ELF_SECTION_LICENSE)
 112 #endif
 113
 114 #ifndef __section_maps
 115 # define __section_maps                                                 \
 116         __section(ELF_SECTION_MAPS)
 117 #endif
 118
 119 /** Declaration helper macros. */
 120
 121 #ifndef BPF_LICENSE
 122 # define BPF_LICENSE(NAME)                                              \
 123         char ____license[] __section_license = NAME
 124 #endif
 125
 126 /** Classifier helper */
 127
 128 #ifndef BPF_H_DEFAULT
 129 # define BPF_H_DEFAULT  -1
 130 #endif
 131
 132 /** BPF helper functions for tc. Individual flags are in linux/bpf.h */
 133
 134 #ifndef __BPF_FUNC
 135 # define __BPF_FUNC(NAME, ...)                                          \
 136         (* NAME)(__VA_ARGS__) __maybe_unused
 137 #endif
 138
 139 #ifndef BPF_FUNC
 140 # define BPF_FUNC(NAME, ...)                                            \
 141         __BPF_FUNC(NAME, __VA_ARGS__) = (void *) BPF_FUNC_##NAME
 142 #endif
 143
 144 /* Map access/manipulation */
 145 static void *BPF_FUNC(map_lookup_elem, void *map, const void *key);
 146 static int BPF_FUNC(map_update_elem, void *map, const void *key,
 147                     const void *value, uint32_t flags);
 148 static int BPF_FUNC(map_delete_elem, void *map, const void *key);
 149
 150 /* Time access */
 151 static uint64_t BPF_FUNC(ktime_get_ns);
 152
 153 /* Debugging */
 154
 155 /* FIXME: __attribute__ ((format(printf, 1, 3))) not possible unless
 156  * llvm bug https://llvm.org/bugs/show_bug.cgi?id=26243 gets resolved.
 157  * It would require ____fmt to be made const, which generates a reloc
 158  * entry (non-map).
 159  */
 160 static void BPF_FUNC(trace_printk, const char *fmt, int fmt_size, ...);
 161
 162 #ifndef printt
 163 # define printt(fmt, ...)                                               \
 164         ({                                                              \
 165                 char ____fmt[] = fmt;                                   \
 166                 trace_printk(____fmt, sizeof(____fmt), ##__VA_ARGS__);  \
 167         })
 168 #endif
 169
 170 /* Random numbers */
 171 static uint32_t BPF_FUNC(get_prandom_u32);
 172
 173 /* Tail calls */
 174 static void BPF_FUNC(tail_call, struct __sk_buff *skb, void *map,
 175                      uint32_t index);
 176
 177 /* System helpers */
 178 static uint32_t BPF_FUNC(get_smp_processor_id);
 179 static uint32_t BPF_FUNC(get_numa_node_id);
 180
 181 /* Packet misc meta data */
 182 static uint32_t BPF_FUNC(get_cgroup_classid, struct __sk_buff *skb);
 183 static int BPF_FUNC(skb_under_cgroup, void *map, uint32_t index);
 184
 185 static uint32_t BPF_FUNC(get_route_realm, struct __sk_buff *skb);
 186 static uint32_t BPF_FUNC(get_hash_recalc, struct __sk_buff *skb);
 187 static uint32_t BPF_FUNC(set_hash_invalid, struct __sk_buff *skb);
 188
 189 /* Packet redirection */
 190 static int BPF_FUNC(redirect, int ifindex, uint32_t flags);
 191 static int BPF_FUNC(clone_redirect, struct __sk_buff *skb, int ifindex,
 192                     uint32_t flags);
 193
 194 /* Packet manipulation */
 195 static int BPF_FUNC(skb_load_bytes, struct __sk_buff *skb, uint32_t off,
 196                     void *to, uint32_t len);
 197 static int BPF_FUNC(skb_store_bytes, struct __sk_buff *skb, uint32_t off,
 198                     const void *from, uint32_t len, uint32_t flags);
 199
 200 static int BPF_FUNC(l3_csum_replace, struct __sk_buff *skb, uint32_t off,
 201                     uint32_t from, uint32_t to, uint32_t flags);
 202 static int BPF_FUNC(l4_csum_replace, struct __sk_buff *skb, uint32_t off,
 203                     uint32_t from, uint32_t to, uint32_t flags);
 204 static int BPF_FUNC(csum_diff, const void *from, uint32_t from_size,
 205                     const void *to, uint32_t to_size, uint32_t seed);
 206 static int BPF_FUNC(csum_update, struct __sk_buff *skb, uint32_t wsum);
 207
 208 static int BPF_FUNC(skb_change_type, struct __sk_buff *skb, uint32_t type);
 209 static int BPF_FUNC(skb_change_proto, struct __sk_buff *skb, uint32_t proto,
 210                     uint32_t flags);
 211 static int BPF_FUNC(skb_change_tail, struct __sk_buff *skb, uint32_t nlen,
 212                     uint32_t flags);
 213
 214 static int BPF_FUNC(skb_pull_data, struct __sk_buff *skb, uint32_t len);
 215
 216 /* Event notification */
 217 static int __BPF_FUNC(skb_event_output, struct __sk_buff *skb, void *map,
 218                       uint64_t index, const void *data, uint32_t size) =
 219                       (void *) BPF_FUNC_perf_event_output;
 220
 221 /* Packet vlan encap/decap */
 222 static int BPF_FUNC(skb_vlan_push, struct __sk_buff *skb, uint16_t proto,
 223                     uint16_t vlan_tci);
 224 static int BPF_FUNC(skb_vlan_pop, struct __sk_buff *skb);
 225
 226 /* Packet tunnel encap/decap */
 227 static int BPF_FUNC(skb_get_tunnel_key, struct __sk_buff *skb,
 228                     struct bpf_tunnel_key *to, uint32_t size, uint32_t flags);
 229 static int BPF_FUNC(skb_set_tunnel_key, struct __sk_buff *skb,
 230                     const struct bpf_tunnel_key *from, uint32_t size,
 231                     uint32_t flags);
 232
 233 static int BPF_FUNC(skb_get_tunnel_opt, struct __sk_buff *skb,
 234                     void *to, uint32_t size);
 235 static int BPF_FUNC(skb_set_tunnel_opt, struct __sk_buff *skb,
 236                     const void *from, uint32_t size);
 237
 238 /** LLVM built-ins, mem*() routines work for constant size */
 239
 240 #ifndef lock_xadd
 241 # define lock_xadd(ptr, val)    ((void) __sync_fetch_and_add(ptr, val))
 242 #endif
 243
 244 #ifndef memset
 245 # define memset(s, c, n)        __builtin_memset((s), (c), (n))
 246 #endif
 247
 248 #ifndef memcpy
 249 # define memcpy(d, s, n)        __builtin_memcpy((d), (s), (n))
 250 #endif
 251
 252 #ifndef memmove
 253 # define memmove(d, s, n)       __builtin_memmove((d), (s), (n))
 254 #endif
 255
 256 /* FIXME: __builtin_memcmp() is not yet fully useable unless llvm bug
 257  * https://llvm.org/bugs/show_bug.cgi?id=26218 gets resolved. Also
 258  * this one would generate a reloc entry (non-map), otherwise.
 259  */
 260 #if 0
 261 #ifndef memcmp
 262 # define memcmp(a, b, n)        __builtin_memcmp((a), (b), (n))
 263 #endif
 264 #endif
 265
 266 unsigned long long load_byte(void *skb, unsigned long long off)
 267         asm ("llvm.bpf.load.byte");
 268
 269 unsigned long long load_half(void *skb, unsigned long long off)
 270         asm ("llvm.bpf.load.half");
 271
 272 unsigned long long load_word(void *skb, unsigned long long off)
 273         asm ("llvm.bpf.load.word");
 274
 275 #endif /* __BPF_API__ */