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