1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of version 2 of the GNU General Public
6 * License as published by the Free Software Foundation.
7 */
8#ifndef _UAPI__LINUX_BPF_H__
9#define _UAPI__LINUX_BPF_H__
10
11#include <linux/types.h>
12#include <linux/bpf_common.h>
13
14/* Extended instruction set based on top of classic BPF */
15
16/* instruction classes */
17#define BPF_JMP32 0x06 /* jmp mode in word width */
18#define BPF_ALU64 0x07 /* alu mode in double word width */
19
20/* ld/ldx fields */
21#define BPF_DW 0x18 /* double word (64-bit) */
22#define BPF_XADD 0xc0 /* exclusive add */
23
24/* alu/jmp fields */
25#define BPF_MOV 0xb0 /* mov reg to reg */
26#define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */
27
28/* change endianness of a register */
29#define BPF_END 0xd0 /* flags for endianness conversion: */
30#define BPF_TO_LE 0x00 /* convert to little-endian */
31#define BPF_TO_BE 0x08 /* convert to big-endian */
32#define BPF_FROM_LE BPF_TO_LE
33#define BPF_FROM_BE BPF_TO_BE
34
35/* jmp encodings */
36#define BPF_JNE 0x50 /* jump != */
37#define BPF_JLT 0xa0 /* LT is unsigned, '<' */
38#define BPF_JLE 0xb0 /* LE is unsigned, '<=' */
39#define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */
40#define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */
41#define BPF_JSLT 0xc0 /* SLT is signed, '<' */
42#define BPF_JSLE 0xd0 /* SLE is signed, '<=' */
43#define BPF_CALL 0x80 /* function call */
44#define BPF_EXIT 0x90 /* function return */
45
46/* Register numbers */
47enum {
48 BPF_REG_0 = 0,
49 BPF_REG_1,
50 BPF_REG_2,
51 BPF_REG_3,
52 BPF_REG_4,
53 BPF_REG_5,
54 BPF_REG_6,
55 BPF_REG_7,
56 BPF_REG_8,
57 BPF_REG_9,
58 BPF_REG_10,
59 __MAX_BPF_REG,
60};
61
62/* BPF has 10 general purpose 64-bit registers and stack frame. */
63#define MAX_BPF_REG __MAX_BPF_REG
64
65struct bpf_insn {
66 __u8 code; /* opcode */
67 __u8 dst_reg:4; /* dest register */
68 __u8 src_reg:4; /* source register */
69 __s16 off; /* signed offset */
70 __s32 imm; /* signed immediate constant */
71};
72
73/* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
74struct bpf_lpm_trie_key {
75 __u32 prefixlen; /* up to 32 for AF_INET, 128 for AF_INET6 */
76 __u8 data[0]; /* Arbitrary size */
77};
78
79struct bpf_cgroup_storage_key {
80 __u64 cgroup_inode_id; /* cgroup inode id */
81 __u32 attach_type; /* program attach type */
82};
83
84/* BPF syscall commands, see bpf(2) man-page for details. */
85enum bpf_cmd {
86 BPF_MAP_CREATE,
87 BPF_MAP_LOOKUP_ELEM,
88 BPF_MAP_UPDATE_ELEM,
89 BPF_MAP_DELETE_ELEM,
90 BPF_MAP_GET_NEXT_KEY,
91 BPF_PROG_LOAD,
92 BPF_OBJ_PIN,
93 BPF_OBJ_GET,
94 BPF_PROG_ATTACH,
95 BPF_PROG_DETACH,
96 BPF_PROG_TEST_RUN,
97 BPF_PROG_GET_NEXT_ID,
98 BPF_MAP_GET_NEXT_ID,
99 BPF_PROG_GET_FD_BY_ID,
100 BPF_MAP_GET_FD_BY_ID,
101 BPF_OBJ_GET_INFO_BY_FD,
102 BPF_PROG_QUERY,
103 BPF_RAW_TRACEPOINT_OPEN,
104 BPF_BTF_LOAD,
105 BPF_BTF_GET_FD_BY_ID,
106 BPF_TASK_FD_QUERY,
107 BPF_MAP_LOOKUP_AND_DELETE_ELEM,
108};
109
110enum bpf_map_type {
111 BPF_MAP_TYPE_UNSPEC,
112 BPF_MAP_TYPE_HASH,
113 BPF_MAP_TYPE_ARRAY,
114 BPF_MAP_TYPE_PROG_ARRAY,
115 BPF_MAP_TYPE_PERF_EVENT_ARRAY,
116 BPF_MAP_TYPE_PERCPU_HASH,
117 BPF_MAP_TYPE_PERCPU_ARRAY,
118 BPF_MAP_TYPE_STACK_TRACE,
119 BPF_MAP_TYPE_CGROUP_ARRAY,
120 BPF_MAP_TYPE_LRU_HASH,
121 BPF_MAP_TYPE_LRU_PERCPU_HASH,
122 BPF_MAP_TYPE_LPM_TRIE,
123 BPF_MAP_TYPE_ARRAY_OF_MAPS,
124 BPF_MAP_TYPE_HASH_OF_MAPS,
125 BPF_MAP_TYPE_DEVMAP,
126 BPF_MAP_TYPE_SOCKMAP,
127 BPF_MAP_TYPE_CPUMAP,
128 BPF_MAP_TYPE_XSKMAP,
129 BPF_MAP_TYPE_SOCKHASH,
130 BPF_MAP_TYPE_CGROUP_STORAGE,
131 BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
132 BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
133 BPF_MAP_TYPE_QUEUE,
134 BPF_MAP_TYPE_STACK,
135};
136
137/* Note that tracing related programs such as
138 * BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
139 * are not subject to a stable API since kernel internal data
140 * structures can change from release to release and may
141 * therefore break existing tracing BPF programs. Tracing BPF
142 * programs correspond to /a/ specific kernel which is to be
143 * analyzed, and not /a/ specific kernel /and/ all future ones.
144 */
145enum bpf_prog_type {
146 BPF_PROG_TYPE_UNSPEC,
147 BPF_PROG_TYPE_SOCKET_FILTER,
148 BPF_PROG_TYPE_KPROBE,
149 BPF_PROG_TYPE_SCHED_CLS,
150 BPF_PROG_TYPE_SCHED_ACT,
151 BPF_PROG_TYPE_TRACEPOINT,
152 BPF_PROG_TYPE_XDP,
153 BPF_PROG_TYPE_PERF_EVENT,
154 BPF_PROG_TYPE_CGROUP_SKB,
155 BPF_PROG_TYPE_CGROUP_SOCK,
156 BPF_PROG_TYPE_LWT_IN,
157 BPF_PROG_TYPE_LWT_OUT,
158 BPF_PROG_TYPE_LWT_XMIT,
159 BPF_PROG_TYPE_SOCK_OPS,
160 BPF_PROG_TYPE_SK_SKB,
161 BPF_PROG_TYPE_CGROUP_DEVICE,
162 BPF_PROG_TYPE_SK_MSG,
163 BPF_PROG_TYPE_RAW_TRACEPOINT,
164 BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
165 BPF_PROG_TYPE_LWT_SEG6LOCAL,
166 BPF_PROG_TYPE_LIRC_MODE2,
167 BPF_PROG_TYPE_SK_REUSEPORT,
168 BPF_PROG_TYPE_FLOW_DISSECTOR,
169};
170
171enum bpf_attach_type {
172 BPF_CGROUP_INET_INGRESS,
173 BPF_CGROUP_INET_EGRESS,
174 BPF_CGROUP_INET_SOCK_CREATE,
175 BPF_CGROUP_SOCK_OPS,
176 BPF_SK_SKB_STREAM_PARSER,
177 BPF_SK_SKB_STREAM_VERDICT,
178 BPF_CGROUP_DEVICE,
179 BPF_SK_MSG_VERDICT,
180 BPF_CGROUP_INET4_BIND,
181 BPF_CGROUP_INET6_BIND,
182 BPF_CGROUP_INET4_CONNECT,
183 BPF_CGROUP_INET6_CONNECT,
184 BPF_CGROUP_INET4_POST_BIND,
185 BPF_CGROUP_INET6_POST_BIND,
186 BPF_CGROUP_UDP4_SENDMSG,
187 BPF_CGROUP_UDP6_SENDMSG,
188 BPF_LIRC_MODE2,
189 BPF_FLOW_DISSECTOR,
190 __MAX_BPF_ATTACH_TYPE
191};
192
193#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
194
195/* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
196 *
197 * NONE(default): No further bpf programs allowed in the subtree.
198 *
199 * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
200 * the program in this cgroup yields to sub-cgroup program.
201 *
202 * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
203 * that cgroup program gets run in addition to the program in this cgroup.
204 *
205 * Only one program is allowed to be attached to a cgroup with
206 * NONE or BPF_F_ALLOW_OVERRIDE flag.
207 * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
208 * release old program and attach the new one. Attach flags has to match.
209 *
210 * Multiple programs are allowed to be attached to a cgroup with
211 * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
212 * (those that were attached first, run first)
213 * The programs of sub-cgroup are executed first, then programs of
214 * this cgroup and then programs of parent cgroup.
215 * When children program makes decision (like picking TCP CA or sock bind)
216 * parent program has a chance to override it.
217 *
218 * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
219 * A cgroup with NONE doesn't allow any programs in sub-cgroups.
220 * Ex1:
221 * cgrp1 (MULTI progs A, B) ->
222 * cgrp2 (OVERRIDE prog C) ->
223 * cgrp3 (MULTI prog D) ->
224 * cgrp4 (OVERRIDE prog E) ->
225 * cgrp5 (NONE prog F)
226 * the event in cgrp5 triggers execution of F,D,A,B in that order.
227 * if prog F is detached, the execution is E,D,A,B
228 * if prog F and D are detached, the execution is E,A,B
229 * if prog F, E and D are detached, the execution is C,A,B
230 *
231 * All eligible programs are executed regardless of return code from
232 * earlier programs.
233 */
234#define BPF_F_ALLOW_OVERRIDE (1U << 0)
235#define BPF_F_ALLOW_MULTI (1U << 1)
236
237/* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
238 * verifier will perform strict alignment checking as if the kernel
239 * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
240 * and NET_IP_ALIGN defined to 2.
241 */
242#define BPF_F_STRICT_ALIGNMENT (1U << 0)
243
244/* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
245 * verifier will allow any alignment whatsoever. On platforms
246 * with strict alignment requirements for loads ands stores (such
247 * as sparc and mips) the verifier validates that all loads and
248 * stores provably follow this requirement. This flag turns that
249 * checking and enforcement off.
250 *
251 * It is mostly used for testing when we want to validate the
252 * context and memory access aspects of the verifier, but because
253 * of an unaligned access the alignment check would trigger before
254 * the one we are interested in.
255 */
256#define BPF_F_ANY_ALIGNMENT (1U << 1)
257
258/* when bpf_ldimm64->src_reg == BPF_PSEUDO_MAP_FD, bpf_ldimm64->imm == fd */
259#define BPF_PSEUDO_MAP_FD 1
260
261/* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
262 * offset to another bpf function
263 */
264#define BPF_PSEUDO_CALL 1
265
266/* flags for BPF_MAP_UPDATE_ELEM command */
267#define BPF_ANY 0 /* create new element or update existing */
268#define BPF_NOEXIST 1 /* create new element if it didn't exist */
269#define BPF_EXIST 2 /* update existing element */
270#define BPF_F_LOCK 4 /* spin_lock-ed map_lookup/map_update */
271
272/* flags for BPF_MAP_CREATE command */
273#define BPF_F_NO_PREALLOC (1U << 0)
274/* Instead of having one common LRU list in the
275 * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
276 * which can scale and perform better.
277 * Note, the LRU nodes (including free nodes) cannot be moved
278 * across different LRU lists.
279 */
280#define BPF_F_NO_COMMON_LRU (1U << 1)
281/* Specify numa node during map creation */
282#define BPF_F_NUMA_NODE (1U << 2)
283
284#define BPF_OBJ_NAME_LEN 16U
285
286/* Flags for accessing BPF object */
287#define BPF_F_RDONLY (1U << 3)
288#define BPF_F_WRONLY (1U << 4)
289
290/* Flag for stack_map, store build_id+offset instead of pointer */
291#define BPF_F_STACK_BUILD_ID (1U << 5)
292
293/* Zero-initialize hash function seed. This should only be used for testing. */
294#define BPF_F_ZERO_SEED (1U << 6)
295
296/* flags for BPF_PROG_QUERY */
297#define BPF_F_QUERY_EFFECTIVE (1U << 0)
298
299enum bpf_stack_build_id_status {
300 /* user space need an empty entry to identify end of a trace */
301 BPF_STACK_BUILD_ID_EMPTY = 0,
302 /* with valid build_id and offset */
303 BPF_STACK_BUILD_ID_VALID = 1,
304 /* couldn't get build_id, fallback to ip */
305 BPF_STACK_BUILD_ID_IP = 2,
306};
307
308#define BPF_BUILD_ID_SIZE 20
309struct bpf_stack_build_id {
310 __s32 status;
311 unsigned char build_id[BPF_BUILD_ID_SIZE];
312 union {
313 __u64 offset;
314 __u64 ip;
315 };
316};
317
318union bpf_attr {
319 struct { /* anonymous struct used by BPF_MAP_CREATE command */
320 __u32 map_type; /* one of enum bpf_map_type */
321 __u32 key_size; /* size of key in bytes */
322 __u32 value_size; /* size of value in bytes */
323 __u32 max_entries; /* max number of entries in a map */
324 __u32 map_flags; /* BPF_MAP_CREATE related
325 * flags defined above.
326 */
327 __u32 inner_map_fd; /* fd pointing to the inner map */
328 __u32 numa_node; /* numa node (effective only if
329 * BPF_F_NUMA_NODE is set).
330 */
331 char map_name[BPF_OBJ_NAME_LEN];
332 __u32 map_ifindex; /* ifindex of netdev to create on */
333 __u32 btf_fd; /* fd pointing to a BTF type data */
334 __u32 btf_key_type_id; /* BTF type_id of the key */
335 __u32 btf_value_type_id; /* BTF type_id of the value */
336 };
337
338 struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
339 __u32 map_fd;
340 __aligned_u64 key;
341 union {
342 __aligned_u64 value;
343 __aligned_u64 next_key;
344 };
345 __u64 flags;
346 };
347
348 struct { /* anonymous struct used by BPF_PROG_LOAD command */
349 __u32 prog_type; /* one of enum bpf_prog_type */
350 __u32 insn_cnt;
351 __aligned_u64 insns;
352 __aligned_u64 license;
353 __u32 log_level; /* verbosity level of verifier */
354 __u32 log_size; /* size of user buffer */
355 __aligned_u64 log_buf; /* user supplied buffer */
356 __u32 kern_version; /* not used */
357 __u32 prog_flags;
358 char prog_name[BPF_OBJ_NAME_LEN];
359 __u32 prog_ifindex; /* ifindex of netdev to prep for */
360 /* For some prog types expected attach type must be known at
361 * load time to verify attach type specific parts of prog
362 * (context accesses, allowed helpers, etc).
363 */
364 __u32 expected_attach_type;
365 __u32 prog_btf_fd; /* fd pointing to BTF type data */
366 __u32 func_info_rec_size; /* userspace bpf_func_info size */
367 __aligned_u64 func_info; /* func info */
368 __u32 func_info_cnt; /* number of bpf_func_info records */
369 __u32 line_info_rec_size; /* userspace bpf_line_info size */
370 __aligned_u64 line_info; /* line info */
371 __u32 line_info_cnt; /* number of bpf_line_info records */
372 };
373
374 struct { /* anonymous struct used by BPF_OBJ_* commands */
375 __aligned_u64 pathname;
376 __u32 bpf_fd;
377 __u32 file_flags;
378 };
379
380 struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
381 __u32 target_fd; /* container object to attach to */
382 __u32 attach_bpf_fd; /* eBPF program to attach */
383 __u32 attach_type;
384 __u32 attach_flags;
385 };
386
387 struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
388 __u32 prog_fd;
389 __u32 retval;
390 __u32 data_size_in; /* input: len of data_in */
391 __u32 data_size_out; /* input/output: len of data_out
392 * returns ENOSPC if data_out
393 * is too small.
394 */
395 __aligned_u64 data_in;
396 __aligned_u64 data_out;
397 __u32 repeat;
398 __u32 duration;
399 } test;
400
401 struct { /* anonymous struct used by BPF_*_GET_*_ID */
402 union {
403 __u32 start_id;
404 __u32 prog_id;
405 __u32 map_id;
406 __u32 btf_id;
407 };
408 __u32 next_id;
409 __u32 open_flags;
410 };
411
412 struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
413 __u32 bpf_fd;
414 __u32 info_len;
415 __aligned_u64 info;
416 } info;
417
418 struct { /* anonymous struct used by BPF_PROG_QUERY command */
419 __u32 target_fd; /* container object to query */
420 __u32 attach_type;
421 __u32 query_flags;
422 __u32 attach_flags;
423 __aligned_u64 prog_ids;
424 __u32 prog_cnt;
425 } query;
426
427 struct {
428 __u64 name;
429 __u32 prog_fd;
430 } raw_tracepoint;
431
432 struct { /* anonymous struct for BPF_BTF_LOAD */
433 __aligned_u64 btf;
434 __aligned_u64 btf_log_buf;
435 __u32 btf_size;
436 __u32 btf_log_size;
437 __u32 btf_log_level;
438 };
439
440 struct {
441 __u32 pid; /* input: pid */
442 __u32 fd; /* input: fd */
443 __u32 flags; /* input: flags */
444 __u32 buf_len; /* input/output: buf len */
445 __aligned_u64 buf; /* input/output:
446 * tp_name for tracepoint
447 * symbol for kprobe
448 * filename for uprobe
449 */
450 __u32 prog_id; /* output: prod_id */
451 __u32 fd_type; /* output: BPF_FD_TYPE_* */
452 __u64 probe_offset; /* output: probe_offset */
453 __u64 probe_addr; /* output: probe_addr */
454 } task_fd_query;
455} __attribute__((aligned(8)));
456
457/* The description below is an attempt at providing documentation to eBPF
458 * developers about the multiple available eBPF helper functions. It can be
459 * parsed and used to produce a manual page. The workflow is the following,
460 * and requires the rst2man utility:
461 *
462 * $ ./scripts/bpf_helpers_doc.py \
463 * --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
464 * $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
465 * $ man /tmp/bpf-helpers.7
466 *
467 * Note that in order to produce this external documentation, some RST
468 * formatting is used in the descriptions to get "bold" and "italics" in
469 * manual pages. Also note that the few trailing white spaces are
470 * intentional, removing them would break paragraphs for rst2man.
471 *
472 * Start of BPF helper function descriptions:
473 *
474 * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
475 * Description
476 * Perform a lookup in *map* for an entry associated to *key*.
477 * Return
478 * Map value associated to *key*, or **NULL** if no entry was
479 * found.
480 *
481 * int bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
482 * Description
483 * Add or update the value of the entry associated to *key* in
484 * *map* with *value*. *flags* is one of:
485 *
486 * **BPF_NOEXIST**
487 * The entry for *key* must not exist in the map.
488 * **BPF_EXIST**
489 * The entry for *key* must already exist in the map.
490 * **BPF_ANY**
491 * No condition on the existence of the entry for *key*.
492 *
493 * Flag value **BPF_NOEXIST** cannot be used for maps of types
494 * **BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY** (all
495 * elements always exist), the helper would return an error.
496 * Return
497 * 0 on success, or a negative error in case of failure.
498 *
499 * int bpf_map_delete_elem(struct bpf_map *map, const void *key)
500 * Description
501 * Delete entry with *key* from *map*.
502 * Return
503 * 0 on success, or a negative error in case of failure.
504 *
505 * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
506 * Description
507 * Push an element *value* in *map*. *flags* is one of:
508 *
509 * **BPF_EXIST**
510 * If the queue/stack is full, the oldest element is removed to
511 * make room for this.
512 * Return
513 * 0 on success, or a negative error in case of failure.
514 *
515 * int bpf_probe_read(void *dst, u32 size, const void *src)
516 * Description
517 * For tracing programs, safely attempt to read *size* bytes from
518 * address *src* and store the data in *dst*.
519 * Return
520 * 0 on success, or a negative error in case of failure.
521 *
522 * u64 bpf_ktime_get_ns(void)
523 * Description
524 * Return the time elapsed since system boot, in nanoseconds.
525 * Return
526 * Current *ktime*.
527 *
528 * int bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
529 * Description
530 * This helper is a "printk()-like" facility for debugging. It
531 * prints a message defined by format *fmt* (of size *fmt_size*)
532 * to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
533 * available. It can take up to three additional **u64**
534 * arguments (as an eBPF helpers, the total number of arguments is
535 * limited to five).
536 *
537 * Each time the helper is called, it appends a line to the trace.
538 * The format of the trace is customizable, and the exact output
539 * one will get depends on the options set in
540 * *\/sys/kernel/debug/tracing/trace_options* (see also the
541 * *README* file under the same directory). However, it usually
542 * defaults to something like:
543 *
544 * ::
545 *
546 * telnet-470 [001] .N.. 419421.045894: 0x00000001: <formatted msg>
547 *
548 * In the above:
549 *
550 * * ``telnet`` is the name of the current task.
551 * * ``470`` is the PID of the current task.
552 * * ``001`` is the CPU number on which the task is
553 * running.
554 * * In ``.N..``, each character refers to a set of
555 * options (whether irqs are enabled, scheduling
556 * options, whether hard/softirqs are running, level of
557 * preempt_disabled respectively). **N** means that
558 * **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
559 * are set.
560 * * ``419421.045894`` is a timestamp.
561 * * ``0x00000001`` is a fake value used by BPF for the
562 * instruction pointer register.
563 * * ``<formatted msg>`` is the message formatted with
564 * *fmt*.
565 *
566 * The conversion specifiers supported by *fmt* are similar, but
567 * more limited than for printk(). They are **%d**, **%i**,
568 * **%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
569 * **%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
570 * of field, padding with zeroes, etc.) is available, and the
571 * helper will return **-EINVAL** (but print nothing) if it
572 * encounters an unknown specifier.
573 *
574 * Also, note that **bpf_trace_printk**\ () is slow, and should
575 * only be used for debugging purposes. For this reason, a notice
576 * bloc (spanning several lines) is printed to kernel logs and
577 * states that the helper should not be used "for production use"
578 * the first time this helper is used (or more precisely, when
579 * **trace_printk**\ () buffers are allocated). For passing values
580 * to user space, perf events should be preferred.
581 * Return
582 * The number of bytes written to the buffer, or a negative error
583 * in case of failure.
584 *
585 * u32 bpf_get_prandom_u32(void)
586 * Description
587 * Get a pseudo-random number.
588 *
589 * From a security point of view, this helper uses its own
590 * pseudo-random internal state, and cannot be used to infer the
591 * seed of other random functions in the kernel. However, it is
592 * essential to note that the generator used by the helper is not
593 * cryptographically secure.
594 * Return
595 * A random 32-bit unsigned value.
596 *
597 * u32 bpf_get_smp_processor_id(void)
598 * Description
599 * Get the SMP (symmetric multiprocessing) processor id. Note that
600 * all programs run with preemption disabled, which means that the
601 * SMP processor id is stable during all the execution of the
602 * program.
603 * Return
604 * The SMP id of the processor running the program.
605 *
606 * int bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
607 * Description
608 * Store *len* bytes from address *from* into the packet
609 * associated to *skb*, at *offset*. *flags* are a combination of
610 * **BPF_F_RECOMPUTE_CSUM** (automatically recompute the
611 * checksum for the packet after storing the bytes) and
612 * **BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
613 * **->swhash** and *skb*\ **->l4hash** to 0).
614 *
615 * A call to this helper is susceptible to change the underlaying
616 * packet buffer. Therefore, at load time, all checks on pointers
617 * previously done by the verifier are invalidated and must be
618 * performed again, if the helper is used in combination with
619 * direct packet access.
620 * Return
621 * 0 on success, or a negative error in case of failure.
622 *
623 * int bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
624 * Description
625 * Recompute the layer 3 (e.g. IP) checksum for the packet
626 * associated to *skb*. Computation is incremental, so the helper
627 * must know the former value of the header field that was
628 * modified (*from*), the new value of this field (*to*), and the
629 * number of bytes (2 or 4) for this field, stored in *size*.
630 * Alternatively, it is possible to store the difference between
631 * the previous and the new values of the header field in *to*, by
632 * setting *from* and *size* to 0. For both methods, *offset*
633 * indicates the location of the IP checksum within the packet.
634 *
635 * This helper works in combination with **bpf_csum_diff**\ (),
636 * which does not update the checksum in-place, but offers more
637 * flexibility and can handle sizes larger than 2 or 4 for the
638 * checksum to update.
639 *
640 * A call to this helper is susceptible to change the underlaying
641 * packet buffer. Therefore, at load time, all checks on pointers
642 * previously done by the verifier are invalidated and must be
643 * performed again, if the helper is used in combination with
644 * direct packet access.
645 * Return
646 * 0 on success, or a negative error in case of failure.
647 *
648 * int bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
649 * Description
650 * Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
651 * packet associated to *skb*. Computation is incremental, so the
652 * helper must know the former value of the header field that was
653 * modified (*from*), the new value of this field (*to*), and the
654 * number of bytes (2 or 4) for this field, stored on the lowest
655 * four bits of *flags*. Alternatively, it is possible to store
656 * the difference between the previous and the new values of the
657 * header field in *to*, by setting *from* and the four lowest
658 * bits of *flags* to 0. For both methods, *offset* indicates the
659 * location of the IP checksum within the packet. In addition to
660 * the size of the field, *flags* can be added (bitwise OR) actual
661 * flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
662 * untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
663 * for updates resulting in a null checksum the value is set to
664 * **CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
665 * the checksum is to be computed against a pseudo-header.
666 *
667 * This helper works in combination with **bpf_csum_diff**\ (),
668 * which does not update the checksum in-place, but offers more
669 * flexibility and can handle sizes larger than 2 or 4 for the
670 * checksum to update.
671 *
672 * A call to this helper is susceptible to change the underlaying
673 * packet buffer. Therefore, at load time, all checks on pointers
674 * previously done by the verifier are invalidated and must be
675 * performed again, if the helper is used in combination with
676 * direct packet access.
677 * Return
678 * 0 on success, or a negative error in case of failure.
679 *
680 * int bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
681 * Description
682 * This special helper is used to trigger a "tail call", or in
683 * other words, to jump into another eBPF program. The same stack
684 * frame is used (but values on stack and in registers for the
685 * caller are not accessible to the callee). This mechanism allows
686 * for program chaining, either for raising the maximum number of
687 * available eBPF instructions, or to execute given programs in
688 * conditional blocks. For security reasons, there is an upper
689 * limit to the number of successive tail calls that can be
690 * performed.
691 *
692 * Upon call of this helper, the program attempts to jump into a
693 * program referenced at index *index* in *prog_array_map*, a
694 * special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
695 * *ctx*, a pointer to the context.
696 *
697 * If the call succeeds, the kernel immediately runs the first
698 * instruction of the new program. This is not a function call,
699 * and it never returns to the previous program. If the call
700 * fails, then the helper has no effect, and the caller continues
701 * to run its subsequent instructions. A call can fail if the
702 * destination program for the jump does not exist (i.e. *index*
703 * is superior to the number of entries in *prog_array_map*), or
704 * if the maximum number of tail calls has been reached for this
705 * chain of programs. This limit is defined in the kernel by the
706 * macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
707 * which is currently set to 32.
708 * Return
709 * 0 on success, or a negative error in case of failure.
710 *
711 * int bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
712 * Description
713 * Clone and redirect the packet associated to *skb* to another
714 * net device of index *ifindex*. Both ingress and egress
715 * interfaces can be used for redirection. The **BPF_F_INGRESS**
716 * value in *flags* is used to make the distinction (ingress path
717 * is selected if the flag is present, egress path otherwise).
718 * This is the only flag supported for now.
719 *
720 * In comparison with **bpf_redirect**\ () helper,
721 * **bpf_clone_redirect**\ () has the associated cost of
722 * duplicating the packet buffer, but this can be executed out of
723 * the eBPF program. Conversely, **bpf_redirect**\ () is more
724 * efficient, but it is handled through an action code where the
725 * redirection happens only after the eBPF program has returned.
726 *
727 * A call to this helper is susceptible to change the underlaying
728 * packet buffer. Therefore, at load time, all checks on pointers
729 * previously done by the verifier are invalidated and must be
730 * performed again, if the helper is used in combination with
731 * direct packet access.
732 * Return
733 * 0 on success, or a negative error in case of failure.
734 *
735 * u64 bpf_get_current_pid_tgid(void)
736 * Return
737 * A 64-bit integer containing the current tgid and pid, and
738 * created as such:
739 * *current_task*\ **->tgid << 32 \|**
740 * *current_task*\ **->pid**.
741 *
742 * u64 bpf_get_current_uid_gid(void)
743 * Return
744 * A 64-bit integer containing the current GID and UID, and
745 * created as such: *current_gid* **<< 32 \|** *current_uid*.
746 *
747 * int bpf_get_current_comm(char *buf, u32 size_of_buf)
748 * Description
749 * Copy the **comm** attribute of the current task into *buf* of
750 * *size_of_buf*. The **comm** attribute contains the name of
751 * the executable (excluding the path) for the current task. The
752 * *size_of_buf* must be strictly positive. On success, the
753 * helper makes sure that the *buf* is NUL-terminated. On failure,
754 * it is filled with zeroes.
755 * Return
756 * 0 on success, or a negative error in case of failure.
757 *
758 * u32 bpf_get_cgroup_classid(struct sk_buff *skb)
759 * Description
760 * Retrieve the classid for the current task, i.e. for the net_cls
761 * cgroup to which *skb* belongs.
762 *
763 * This helper can be used on TC egress path, but not on ingress.
764 *
765 * The net_cls cgroup provides an interface to tag network packets
766 * based on a user-provided identifier for all traffic coming from
767 * the tasks belonging to the related cgroup. See also the related
768 * kernel documentation, available from the Linux sources in file
769 * *Documentation/cgroup-v1/net_cls.txt*.
770 *
771 * The Linux kernel has two versions for cgroups: there are
772 * cgroups v1 and cgroups v2. Both are available to users, who can
773 * use a mixture of them, but note that the net_cls cgroup is for
774 * cgroup v1 only. This makes it incompatible with BPF programs
775 * run on cgroups, which is a cgroup-v2-only feature (a socket can
776 * only hold data for one version of cgroups at a time).
777 *
778 * This helper is only available is the kernel was compiled with
779 * the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
780 * "**y**" or to "**m**".
781 * Return
782 * The classid, or 0 for the default unconfigured classid.
783 *
784 * int bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
785 * Description
786 * Push a *vlan_tci* (VLAN tag control information) of protocol
787 * *vlan_proto* to the packet associated to *skb*, then update
788 * the checksum. Note that if *vlan_proto* is different from
789 * **ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
790 * be **ETH_P_8021Q**.
791 *
792 * A call to this helper is susceptible to change the underlaying
793 * packet buffer. Therefore, at load time, all checks on pointers
794 * previously done by the verifier are invalidated and must be
795 * performed again, if the helper is used in combination with
796 * direct packet access.
797 * Return
798 * 0 on success, or a negative error in case of failure.
799 *
800 * int bpf_skb_vlan_pop(struct sk_buff *skb)
801 * Description
802 * Pop a VLAN header from the packet associated to *skb*.
803 *
804 * A call to this helper is susceptible to change the underlaying
805 * packet buffer. Therefore, at load time, all checks on pointers
806 * previously done by the verifier are invalidated and must be
807 * performed again, if the helper is used in combination with
808 * direct packet access.
809 * Return
810 * 0 on success, or a negative error in case of failure.
811 *
812 * int bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
813 * Description
814 * Get tunnel metadata. This helper takes a pointer *key* to an
815 * empty **struct bpf_tunnel_key** of **size**, that will be
816 * filled with tunnel metadata for the packet associated to *skb*.
817 * The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
818 * indicates that the tunnel is based on IPv6 protocol instead of
819 * IPv4.
820 *
821 * The **struct bpf_tunnel_key** is an object that generalizes the
822 * principal parameters used by various tunneling protocols into a
823 * single struct. This way, it can be used to easily make a
824 * decision based on the contents of the encapsulation header,
825 * "summarized" in this struct. In particular, it holds the IP
826 * address of the remote end (IPv4 or IPv6, depending on the case)
827 * in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
828 * this struct exposes the *key*\ **->tunnel_id**, which is
829 * generally mapped to a VNI (Virtual Network Identifier), making
830 * it programmable together with the **bpf_skb_set_tunnel_key**\
831 * () helper.
832 *
833 * Let's imagine that the following code is part of a program
834 * attached to the TC ingress interface, on one end of a GRE
835 * tunnel, and is supposed to filter out all messages coming from
836 * remote ends with IPv4 address other than 10.0.0.1:
837 *
838 * ::
839 *
840 * int ret;
841 * struct bpf_tunnel_key key = {};
842 *
843 * ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
844 * if (ret < 0)
845 * return TC_ACT_SHOT; // drop packet
846 *
847 * if (key.remote_ipv4 != 0x0a000001)
848 * return TC_ACT_SHOT; // drop packet
849 *
850 * return TC_ACT_OK; // accept packet
851 *
852 * This interface can also be used with all encapsulation devices
853 * that can operate in "collect metadata" mode: instead of having
854 * one network device per specific configuration, the "collect
855 * metadata" mode only requires a single device where the
856 * configuration can be extracted from this helper.
857 *
858 * This can be used together with various tunnels such as VXLan,
859 * Geneve, GRE or IP in IP (IPIP).
860 * Return
861 * 0 on success, or a negative error in case of failure.
862 *
863 * int bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
864 * Description
865 * Populate tunnel metadata for packet associated to *skb.* The
866 * tunnel metadata is set to the contents of *key*, of *size*. The
867 * *flags* can be set to a combination of the following values:
868 *
869 * **BPF_F_TUNINFO_IPV6**
870 * Indicate that the tunnel is based on IPv6 protocol
871 * instead of IPv4.
872 * **BPF_F_ZERO_CSUM_TX**
873 * For IPv4 packets, add a flag to tunnel metadata
874 * indicating that checksum computation should be skipped
875 * and checksum set to zeroes.
876 * **BPF_F_DONT_FRAGMENT**
877 * Add a flag to tunnel metadata indicating that the
878 * packet should not be fragmented.
879 * **BPF_F_SEQ_NUMBER**
880 * Add a flag to tunnel metadata indicating that a
881 * sequence number should be added to tunnel header before
882 * sending the packet. This flag was added for GRE
883 * encapsulation, but might be used with other protocols
884 * as well in the future.
885 *
886 * Here is a typical usage on the transmit path:
887 *
888 * ::
889 *
890 * struct bpf_tunnel_key key;
891 * populate key ...
892 * bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
893 * bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
894 *
895 * See also the description of the **bpf_skb_get_tunnel_key**\ ()
896 * helper for additional information.
897 * Return
898 * 0 on success, or a negative error in case of failure.
899 *
900 * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
901 * Description
902 * Read the value of a perf event counter. This helper relies on a
903 * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
904 * the perf event counter is selected when *map* is updated with
905 * perf event file descriptors. The *map* is an array whose size
906 * is the number of available CPUs, and each cell contains a value
907 * relative to one CPU. The value to retrieve is indicated by
908 * *flags*, that contains the index of the CPU to look up, masked
909 * with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
910 * **BPF_F_CURRENT_CPU** to indicate that the value for the
911 * current CPU should be retrieved.
912 *
913 * Note that before Linux 4.13, only hardware perf event can be
914 * retrieved.
915 *
916 * Also, be aware that the newer helper
917 * **bpf_perf_event_read_value**\ () is recommended over
918 * **bpf_perf_event_read**\ () in general. The latter has some ABI
919 * quirks where error and counter value are used as a return code
920 * (which is wrong to do since ranges may overlap). This issue is
921 * fixed with **bpf_perf_event_read_value**\ (), which at the same
922 * time provides more features over the **bpf_perf_event_read**\
923 * () interface. Please refer to the description of
924 * **bpf_perf_event_read_value**\ () for details.
925 * Return
926 * The value of the perf event counter read from the map, or a
927 * negative error code in case of failure.
928 *
929 * int bpf_redirect(u32 ifindex, u64 flags)
930 * Description
931 * Redirect the packet to another net device of index *ifindex*.
932 * This helper is somewhat similar to **bpf_clone_redirect**\
933 * (), except that the packet is not cloned, which provides
934 * increased performance.
935 *
936 * Except for XDP, both ingress and egress interfaces can be used
937 * for redirection. The **BPF_F_INGRESS** value in *flags* is used
938 * to make the distinction (ingress path is selected if the flag
939 * is present, egress path otherwise). Currently, XDP only
940 * supports redirection to the egress interface, and accepts no
941 * flag at all.
942 *
943 * The same effect can be attained with the more generic
944 * **bpf_redirect_map**\ (), which requires specific maps to be
945 * used but offers better performance.
946 * Return
947 * For XDP, the helper returns **XDP_REDIRECT** on success or
948 * **XDP_ABORTED** on error. For other program types, the values
949 * are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
950 * error.
951 *
952 * u32 bpf_get_route_realm(struct sk_buff *skb)
953 * Description
954 * Retrieve the realm or the route, that is to say the
955 * **tclassid** field of the destination for the *skb*. The
956 * indentifier retrieved is a user-provided tag, similar to the
957 * one used with the net_cls cgroup (see description for
958 * **bpf_get_cgroup_classid**\ () helper), but here this tag is
959 * held by a route (a destination entry), not by a task.
960 *
961 * Retrieving this identifier works with the clsact TC egress hook
962 * (see also **tc-bpf(8)**), or alternatively on conventional
963 * classful egress qdiscs, but not on TC ingress path. In case of
964 * clsact TC egress hook, this has the advantage that, internally,
965 * the destination entry has not been dropped yet in the transmit
966 * path. Therefore, the destination entry does not need to be
967 * artificially held via **netif_keep_dst**\ () for a classful
968 * qdisc until the *skb* is freed.
969 *
970 * This helper is available only if the kernel was compiled with
971 * **CONFIG_IP_ROUTE_CLASSID** configuration option.
972 * Return
973 * The realm of the route for the packet associated to *skb*, or 0
974 * if none was found.
975 *
976 * int bpf_perf_event_output(struct pt_reg *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
977 * Description
978 * Write raw *data* blob into a special BPF perf event held by
979 * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
980 * event must have the following attributes: **PERF_SAMPLE_RAW**
981 * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
982 * **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
983 *
984 * The *flags* are used to indicate the index in *map* for which
985 * the value must be put, masked with **BPF_F_INDEX_MASK**.
986 * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
987 * to indicate that the index of the current CPU core should be
988 * used.
989 *
990 * The value to write, of *size*, is passed through eBPF stack and
991 * pointed by *data*.
992 *
993 * The context of the program *ctx* needs also be passed to the
994 * helper.
995 *
996 * On user space, a program willing to read the values needs to
997 * call **perf_event_open**\ () on the perf event (either for
998 * one or for all CPUs) and to store the file descriptor into the
999 * *map*. This must be done before the eBPF program can send data
1000 * into it. An example is available in file
1001 * *samples/bpf/trace_output_user.c* in the Linux kernel source
1002 * tree (the eBPF program counterpart is in
1003 * *samples/bpf/trace_output_kern.c*).
1004 *
1005 * **bpf_perf_event_output**\ () achieves better performance
1006 * than **bpf_trace_printk**\ () for sharing data with user
1007 * space, and is much better suitable for streaming data from eBPF
1008 * programs.
1009 *
1010 * Note that this helper is not restricted to tracing use cases
1011 * and can be used with programs attached to TC or XDP as well,
1012 * where it allows for passing data to user space listeners. Data
1013 * can be:
1014 *
1015 * * Only custom structs,
1016 * * Only the packet payload, or
1017 * * A combination of both.
1018 * Return
1019 * 0 on success, or a negative error in case of failure.
1020 *
1021 * int bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len)
1022 * Description
1023 * This helper was provided as an easy way to load data from a
1024 * packet. It can be used to load *len* bytes from *offset* from
1025 * the packet associated to *skb*, into the buffer pointed by
1026 * *to*.
1027 *
1028 * Since Linux 4.7, usage of this helper has mostly been replaced
1029 * by "direct packet access", enabling packet data to be
1030 * manipulated with *skb*\ **->data** and *skb*\ **->data_end**
1031 * pointing respectively to the first byte of packet data and to
1032 * the byte after the last byte of packet data. However, it
1033 * remains useful if one wishes to read large quantities of data
1034 * at once from a packet into the eBPF stack.
1035 * Return
1036 * 0 on success, or a negative error in case of failure.
1037 *
1038 * int bpf_get_stackid(struct pt_reg *ctx, struct bpf_map *map, u64 flags)
1039 * Description
1040 * Walk a user or a kernel stack and return its id. To achieve
1041 * this, the helper needs *ctx*, which is a pointer to the context
1042 * on which the tracing program is executed, and a pointer to a
1043 * *map* of type **BPF_MAP_TYPE_STACK_TRACE**.
1044 *
1045 * The last argument, *flags*, holds the number of stack frames to
1046 * skip (from 0 to 255), masked with
1047 * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
1048 * a combination of the following flags:
1049 *
1050 * **BPF_F_USER_STACK**
1051 * Collect a user space stack instead of a kernel stack.
1052 * **BPF_F_FAST_STACK_CMP**
1053 * Compare stacks by hash only.
1054 * **BPF_F_REUSE_STACKID**
1055 * If two different stacks hash into the same *stackid*,
1056 * discard the old one.
1057 *
1058 * The stack id retrieved is a 32 bit long integer handle which
1059 * can be further combined with other data (including other stack
1060 * ids) and used as a key into maps. This can be useful for
1061 * generating a variety of graphs (such as flame graphs or off-cpu
1062 * graphs).
1063 *
1064 * For walking a stack, this helper is an improvement over
1065 * **bpf_probe_read**\ (), which can be used with unrolled loops
1066 * but is not efficient and consumes a lot of eBPF instructions.
1067 * Instead, **bpf_get_stackid**\ () can collect up to
1068 * **PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
1069 * this limit can be controlled with the **sysctl** program, and
1070 * that it should be manually increased in order to profile long
1071 * user stacks (such as stacks for Java programs). To do so, use:
1072 *
1073 * ::
1074 *
1075 * # sysctl kernel.perf_event_max_stack=<new value>
1076 * Return
1077 * The positive or null stack id on success, or a negative error
1078 * in case of failure.
1079 *
1080 * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
1081 * Description
1082 * Compute a checksum difference, from the raw buffer pointed by
1083 * *from*, of length *from_size* (that must be a multiple of 4),
1084 * towards the raw buffer pointed by *to*, of size *to_size*
1085 * (same remark). An optional *seed* can be added to the value
1086 * (this can be cascaded, the seed may come from a previous call
1087 * to the helper).
1088 *
1089 * This is flexible enough to be used in several ways:
1090 *
1091 * * With *from_size* == 0, *to_size* > 0 and *seed* set to
1092 * checksum, it can be used when pushing new data.
1093 * * With *from_size* > 0, *to_size* == 0 and *seed* set to
1094 * checksum, it can be used when removing data from a packet.
1095 * * With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
1096 * can be used to compute a diff. Note that *from_size* and
1097 * *to_size* do not need to be equal.
1098 *
1099 * This helper can be used in combination with
1100 * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
1101 * which one can feed in the difference computed with
1102 * **bpf_csum_diff**\ ().
1103 * Return
1104 * The checksum result, or a negative error code in case of
1105 * failure.
1106 *
1107 * int bpf_skb_get_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
1108 * Description
1109 * Retrieve tunnel options metadata for the packet associated to
1110 * *skb*, and store the raw tunnel option data to the buffer *opt*
1111 * of *size*.
1112 *
1113 * This helper can be used with encapsulation devices that can
1114 * operate in "collect metadata" mode (please refer to the related
1115 * note in the description of **bpf_skb_get_tunnel_key**\ () for
1116 * more details). A particular example where this can be used is
1117 * in combination with the Geneve encapsulation protocol, where it
1118 * allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
1119 * and retrieving arbitrary TLVs (Type-Length-Value headers) from
1120 * the eBPF program. This allows for full customization of these
1121 * headers.
1122 * Return
1123 * The size of the option data retrieved.
1124 *
1125 * int bpf_skb_set_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
1126 * Description
1127 * Set tunnel options metadata for the packet associated to *skb*
1128 * to the option data contained in the raw buffer *opt* of *size*.
1129 *
1130 * See also the description of the **bpf_skb_get_tunnel_opt**\ ()
1131 * helper for additional information.
1132 * Return
1133 * 0 on success, or a negative error in case of failure.
1134 *
1135 * int bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
1136 * Description
1137 * Change the protocol of the *skb* to *proto*. Currently
1138 * supported are transition from IPv4 to IPv6, and from IPv6 to
1139 * IPv4. The helper takes care of the groundwork for the
1140 * transition, including resizing the socket buffer. The eBPF
1141 * program is expected to fill the new headers, if any, via
1142 * **skb_store_bytes**\ () and to recompute the checksums with
1143 * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
1144 * (). The main case for this helper is to perform NAT64
1145 * operations out of an eBPF program.
1146 *
1147 * Internally, the GSO type is marked as dodgy so that headers are
1148 * checked and segments are recalculated by the GSO/GRO engine.
1149 * The size for GSO target is adapted as well.
1150 *
1151 * All values for *flags* are reserved for future usage, and must
1152 * be left at zero.
1153 *
1154 * A call to this helper is susceptible to change the underlaying
1155 * packet buffer. Therefore, at load time, all checks on pointers
1156 * previously done by the verifier are invalidated and must be
1157 * performed again, if the helper is used in combination with
1158 * direct packet access.
1159 * Return
1160 * 0 on success, or a negative error in case of failure.
1161 *
1162 * int bpf_skb_change_type(struct sk_buff *skb, u32 type)
1163 * Description
1164 * Change the packet type for the packet associated to *skb*. This
1165 * comes down to setting *skb*\ **->pkt_type** to *type*, except
1166 * the eBPF program does not have a write access to *skb*\
1167 * **->pkt_type** beside this helper. Using a helper here allows
1168 * for graceful handling of errors.
1169 *
1170 * The major use case is to change incoming *skb*s to
1171 * **PACKET_HOST** in a programmatic way instead of having to
1172 * recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
1173 * example.
1174 *
1175 * Note that *type* only allows certain values. At this time, they
1176 * are:
1177 *
1178 * **PACKET_HOST**
1179 * Packet is for us.
1180 * **PACKET_BROADCAST**
1181 * Send packet to all.
1182 * **PACKET_MULTICAST**
1183 * Send packet to group.
1184 * **PACKET_OTHERHOST**
1185 * Send packet to someone else.
1186 * Return
1187 * 0 on success, or a negative error in case of failure.
1188 *
1189 * int bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
1190 * Description
1191 * Check whether *skb* is a descendant of the cgroup2 held by
1192 * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
1193 * Return
1194 * The return value depends on the result of the test, and can be:
1195 *
1196 * * 0, if the *skb* failed the cgroup2 descendant test.
1197 * * 1, if the *skb* succeeded the cgroup2 descendant test.
1198 * * A negative error code, if an error occurred.
1199 *
1200 * u32 bpf_get_hash_recalc(struct sk_buff *skb)
1201 * Description
1202 * Retrieve the hash of the packet, *skb*\ **->hash**. If it is
1203 * not set, in particular if the hash was cleared due to mangling,
1204 * recompute this hash. Later accesses to the hash can be done
1205 * directly with *skb*\ **->hash**.
1206 *
1207 * Calling **bpf_set_hash_invalid**\ (), changing a packet
1208 * prototype with **bpf_skb_change_proto**\ (), or calling
1209 * **bpf_skb_store_bytes**\ () with the
1210 * **BPF_F_INVALIDATE_HASH** are actions susceptible to clear
1211 * the hash and to trigger a new computation for the next call to
1212 * **bpf_get_hash_recalc**\ ().
1213 * Return
1214 * The 32-bit hash.
1215 *
1216 * u64 bpf_get_current_task(void)
1217 * Return
1218 * A pointer to the current task struct.
1219 *
1220 * int bpf_probe_write_user(void *dst, const void *src, u32 len)
1221 * Description
1222 * Attempt in a safe way to write *len* bytes from the buffer
1223 * *src* to *dst* in memory. It only works for threads that are in
1224 * user context, and *dst* must be a valid user space address.
1225 *
1226 * This helper should not be used to implement any kind of
1227 * security mechanism because of TOC-TOU attacks, but rather to
1228 * debug, divert, and manipulate execution of semi-cooperative
1229 * processes.
1230 *
1231 * Keep in mind that this feature is meant for experiments, and it
1232 * has a risk of crashing the system and running programs.
1233 * Therefore, when an eBPF program using this helper is attached,
1234 * a warning including PID and process name is printed to kernel
1235 * logs.
1236 * Return
1237 * 0 on success, or a negative error in case of failure.
1238 *
1239 * int bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
1240 * Description
1241 * Check whether the probe is being run is the context of a given
1242 * subset of the cgroup2 hierarchy. The cgroup2 to test is held by
1243 * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
1244 * Return
1245 * The return value depends on the result of the test, and can be:
1246 *
1247 * * 0, if the *skb* task belongs to the cgroup2.
1248 * * 1, if the *skb* task does not belong to the cgroup2.
1249 * * A negative error code, if an error occurred.
1250 *
1251 * int bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
1252 * Description
1253 * Resize (trim or grow) the packet associated to *skb* to the
1254 * new *len*. The *flags* are reserved for future usage, and must
1255 * be left at zero.
1256 *
1257 * The basic idea is that the helper performs the needed work to
1258 * change the size of the packet, then the eBPF program rewrites
1259 * the rest via helpers like **bpf_skb_store_bytes**\ (),
1260 * **bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
1261 * and others. This helper is a slow path utility intended for
1262 * replies with control messages. And because it is targeted for
1263 * slow path, the helper itself can afford to be slow: it
1264 * implicitly linearizes, unclones and drops offloads from the
1265 * *skb*.
1266 *
1267 * A call to this helper is susceptible to change the underlaying
1268 * packet buffer. Therefore, at load time, all checks on pointers
1269 * previously done by the verifier are invalidated and must be
1270 * performed again, if the helper is used in combination with
1271 * direct packet access.
1272 * Return
1273 * 0 on success, or a negative error in case of failure.
1274 *
1275 * int bpf_skb_pull_data(struct sk_buff *skb, u32 len)
1276 * Description
1277 * Pull in non-linear data in case the *skb* is non-linear and not
1278 * all of *len* are part of the linear section. Make *len* bytes
1279 * from *skb* readable and writable. If a zero value is passed for
1280 * *len*, then the whole length of the *skb* is pulled.
1281 *
1282 * This helper is only needed for reading and writing with direct
1283 * packet access.
1284 *
1285 * For direct packet access, testing that offsets to access
1286 * are within packet boundaries (test on *skb*\ **->data_end**) is
1287 * susceptible to fail if offsets are invalid, or if the requested
1288 * data is in non-linear parts of the *skb*. On failure the
1289 * program can just bail out, or in the case of a non-linear
1290 * buffer, use a helper to make the data available. The
1291 * **bpf_skb_load_bytes**\ () helper is a first solution to access
1292 * the data. Another one consists in using **bpf_skb_pull_data**
1293 * to pull in once the non-linear parts, then retesting and
1294 * eventually access the data.
1295 *
1296 * At the same time, this also makes sure the *skb* is uncloned,
1297 * which is a necessary condition for direct write. As this needs
1298 * to be an invariant for the write part only, the verifier
1299 * detects writes and adds a prologue that is calling
1300 * **bpf_skb_pull_data()** to effectively unclone the *skb* from
1301 * the very beginning in case it is indeed cloned.
1302 *
1303 * A call to this helper is susceptible to change the underlaying
1304 * packet buffer. Therefore, at load time, all checks on pointers
1305 * previously done by the verifier are invalidated and must be
1306 * performed again, if the helper is used in combination with
1307 * direct packet access.
1308 * Return
1309 * 0 on success, or a negative error in case of failure.
1310 *
1311 * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
1312 * Description
1313 * Add the checksum *csum* into *skb*\ **->csum** in case the
1314 * driver has supplied a checksum for the entire packet into that
1315 * field. Return an error otherwise. This helper is intended to be
1316 * used in combination with **bpf_csum_diff**\ (), in particular
1317 * when the checksum needs to be updated after data has been
1318 * written into the packet through direct packet access.
1319 * Return
1320 * The checksum on success, or a negative error code in case of
1321 * failure.
1322 *
1323 * void bpf_set_hash_invalid(struct sk_buff *skb)
1324 * Description
1325 * Invalidate the current *skb*\ **->hash**. It can be used after
1326 * mangling on headers through direct packet access, in order to
1327 * indicate that the hash is outdated and to trigger a
1328 * recalculation the next time the kernel tries to access this
1329 * hash or when the **bpf_get_hash_recalc**\ () helper is called.
1330 *
1331 * int bpf_get_numa_node_id(void)
1332 * Description
1333 * Return the id of the current NUMA node. The primary use case
1334 * for this helper is the selection of sockets for the local NUMA
1335 * node, when the program is attached to sockets using the
1336 * **SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
1337 * but the helper is also available to other eBPF program types,
1338 * similarly to **bpf_get_smp_processor_id**\ ().
1339 * Return
1340 * The id of current NUMA node.
1341 *
1342 * int bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
1343 * Description
1344 * Grows headroom of packet associated to *skb* and adjusts the
1345 * offset of the MAC header accordingly, adding *len* bytes of
1346 * space. It automatically extends and reallocates memory as
1347 * required.
1348 *
1349 * This helper can be used on a layer 3 *skb* to push a MAC header
1350 * for redirection into a layer 2 device.
1351 *
1352 * All values for *flags* are reserved for future usage, and must
1353 * be left at zero.
1354 *
1355 * A call to this helper is susceptible to change the underlaying
1356 * packet buffer. Therefore, at load time, all checks on pointers
1357 * previously done by the verifier are invalidated and must be
1358 * performed again, if the helper is used in combination with
1359 * direct packet access.
1360 * Return
1361 * 0 on success, or a negative error in case of failure.
1362 *
1363 * int bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
1364 * Description
1365 * Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
1366 * it is possible to use a negative value for *delta*. This helper
1367 * can be used to prepare the packet for pushing or popping
1368 * headers.
1369 *
1370 * A call to this helper is susceptible to change the underlaying
1371 * packet buffer. Therefore, at load time, all checks on pointers
1372 * previously done by the verifier are invalidated and must be
1373 * performed again, if the helper is used in combination with
1374 * direct packet access.
1375 * Return
1376 * 0 on success, or a negative error in case of failure.
1377 *
1378 * int bpf_probe_read_str(void *dst, int size, const void *unsafe_ptr)
1379 * Description
1380 * Copy a NUL terminated string from an unsafe address
1381 * *unsafe_ptr* to *dst*. The *size* should include the
1382 * terminating NUL byte. In case the string length is smaller than
1383 * *size*, the target is not padded with further NUL bytes. If the
1384 * string length is larger than *size*, just *size*-1 bytes are
1385 * copied and the last byte is set to NUL.
1386 *
1387 * On success, the length of the copied string is returned. This
1388 * makes this helper useful in tracing programs for reading
1389 * strings, and more importantly to get its length at runtime. See
1390 * the following snippet:
1391 *
1392 * ::
1393 *
1394 * SEC("kprobe/sys_open")
1395 * void bpf_sys_open(struct pt_regs *ctx)
1396 * {
1397 * char buf[PATHLEN]; // PATHLEN is defined to 256
1398 * int res = bpf_probe_read_str(buf, sizeof(buf),
1399 * ctx->di);
1400 *
1401 * // Consume buf, for example push it to
1402 * // userspace via bpf_perf_event_output(); we
1403 * // can use res (the string length) as event
1404 * // size, after checking its boundaries.
1405 * }
1406 *
1407 * In comparison, using **bpf_probe_read()** helper here instead
1408 * to read the string would require to estimate the length at
1409 * compile time, and would often result in copying more memory
1410 * than necessary.
1411 *
1412 * Another useful use case is when parsing individual process
1413 * arguments or individual environment variables navigating
1414 * *current*\ **->mm->arg_start** and *current*\
1415 * **->mm->env_start**: using this helper and the return value,
1416 * one can quickly iterate at the right offset of the memory area.
1417 * Return
1418 * On success, the strictly positive length of the string,
1419 * including the trailing NUL character. On error, a negative
1420 * value.
1421 *
1422 * u64 bpf_get_socket_cookie(struct sk_buff *skb)
1423 * Description
1424 * If the **struct sk_buff** pointed by *skb* has a known socket,
1425 * retrieve the cookie (generated by the kernel) of this socket.
1426 * If no cookie has been set yet, generate a new cookie. Once
1427 * generated, the socket cookie remains stable for the life of the
1428 * socket. This helper can be useful for monitoring per socket
1429 * networking traffic statistics as it provides a unique socket
1430 * identifier per namespace.
1431 * Return
1432 * A 8-byte long non-decreasing number on success, or 0 if the
1433 * socket field is missing inside *skb*.
1434 *
1435 * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
1436 * Description
1437 * Equivalent to bpf_get_socket_cookie() helper that accepts
1438 * *skb*, but gets socket from **struct bpf_sock_addr** contex.
1439 * Return
1440 * A 8-byte long non-decreasing number.
1441 *
1442 * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
1443 * Description
1444 * Equivalent to bpf_get_socket_cookie() helper that accepts
1445 * *skb*, but gets socket from **struct bpf_sock_ops** contex.
1446 * Return
1447 * A 8-byte long non-decreasing number.
1448 *
1449 * u32 bpf_get_socket_uid(struct sk_buff *skb)
1450 * Return
1451 * The owner UID of the socket associated to *skb*. If the socket
1452 * is **NULL**, or if it is not a full socket (i.e. if it is a
1453 * time-wait or a request socket instead), **overflowuid** value
1454 * is returned (note that **overflowuid** might also be the actual
1455 * UID value for the socket).
1456 *
1457 * u32 bpf_set_hash(struct sk_buff *skb, u32 hash)
1458 * Description
1459 * Set the full hash for *skb* (set the field *skb*\ **->hash**)
1460 * to value *hash*.
1461 * Return
1462 * 0
1463 *
1464 * int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
1465 * Description
1466 * Emulate a call to **setsockopt()** on the socket associated to
1467 * *bpf_socket*, which must be a full socket. The *level* at
1468 * which the option resides and the name *optname* of the option
1469 * must be specified, see **setsockopt(2)** for more information.
1470 * The option value of length *optlen* is pointed by *optval*.
1471 *
1472 * This helper actually implements a subset of **setsockopt()**.
1473 * It supports the following *level*\ s:
1474 *
1475 * * **SOL_SOCKET**, which supports the following *optname*\ s:
1476 * **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
1477 * **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**.
1478 * * **IPPROTO_TCP**, which supports the following *optname*\ s:
1479 * **TCP_CONGESTION**, **TCP_BPF_IW**,
1480 * **TCP_BPF_SNDCWND_CLAMP**.
1481 * * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
1482 * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
1483 * Return
1484 * 0 on success, or a negative error in case of failure.
1485 *
1486 * int bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
1487 * Description
1488 * Grow or shrink the room for data in the packet associated to
1489 * *skb* by *len_diff*, and according to the selected *mode*.
1490 *
1491 * There is a single supported mode at this time:
1492 *
1493 * * **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
1494 * (room space is added or removed below the layer 3 header).
1495 *
1496 * All values for *flags* are reserved for future usage, and must
1497 * be left at zero.
1498 *
1499 * A call to this helper is susceptible to change the underlaying
1500 * packet buffer. Therefore, at load time, all checks on pointers
1501 * previously done by the verifier are invalidated and must be
1502 * performed again, if the helper is used in combination with
1503 * direct packet access.
1504 * Return
1505 * 0 on success, or a negative error in case of failure.
1506 *
1507 * int bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
1508 * Description
1509 * Redirect the packet to the endpoint referenced by *map* at
1510 * index *key*. Depending on its type, this *map* can contain
1511 * references to net devices (for forwarding packets through other
1512 * ports), or to CPUs (for redirecting XDP frames to another CPU;
1513 * but this is only implemented for native XDP (with driver
1514 * support) as of this writing).
1515 *
1516 * All values for *flags* are reserved for future usage, and must
1517 * be left at zero.
1518 *
1519 * When used to redirect packets to net devices, this helper
1520 * provides a high performance increase over **bpf_redirect**\ ().
1521 * This is due to various implementation details of the underlying
1522 * mechanisms, one of which is the fact that **bpf_redirect_map**\
1523 * () tries to send packet as a "bulk" to the device.
1524 * Return
1525 * **XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
1526 *
1527 * int bpf_sk_redirect_map(struct bpf_map *map, u32 key, u64 flags)
1528 * Description
1529 * Redirect the packet to the socket referenced by *map* (of type
1530 * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
1531 * egress interfaces can be used for redirection. The
1532 * **BPF_F_INGRESS** value in *flags* is used to make the
1533 * distinction (ingress path is selected if the flag is present,
1534 * egress path otherwise). This is the only flag supported for now.
1535 * Return
1536 * **SK_PASS** on success, or **SK_DROP** on error.
1537 *
1538 * int bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
1539 * Description
1540 * Add an entry to, or update a *map* referencing sockets. The
1541 * *skops* is used as a new value for the entry associated to
1542 * *key*. *flags* is one of:
1543 *
1544 * **BPF_NOEXIST**
1545 * The entry for *key* must not exist in the map.
1546 * **BPF_EXIST**
1547 * The entry for *key* must already exist in the map.
1548 * **BPF_ANY**
1549 * No condition on the existence of the entry for *key*.
1550 *
1551 * If the *map* has eBPF programs (parser and verdict), those will
1552 * be inherited by the socket being added. If the socket is
1553 * already attached to eBPF programs, this results in an error.
1554 * Return
1555 * 0 on success, or a negative error in case of failure.
1556 *
1557 * int bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
1558 * Description
1559 * Adjust the address pointed by *xdp_md*\ **->data_meta** by
1560 * *delta* (which can be positive or negative). Note that this
1561 * operation modifies the address stored in *xdp_md*\ **->data**,
1562 * so the latter must be loaded only after the helper has been
1563 * called.
1564 *
1565 * The use of *xdp_md*\ **->data_meta** is optional and programs
1566 * are not required to use it. The rationale is that when the
1567 * packet is processed with XDP (e.g. as DoS filter), it is
1568 * possible to push further meta data along with it before passing
1569 * to the stack, and to give the guarantee that an ingress eBPF
1570 * program attached as a TC classifier on the same device can pick
1571 * this up for further post-processing. Since TC works with socket
1572 * buffers, it remains possible to set from XDP the **mark** or
1573 * **priority** pointers, or other pointers for the socket buffer.
1574 * Having this scratch space generic and programmable allows for
1575 * more flexibility as the user is free to store whatever meta
1576 * data they need.
1577 *
1578 * A call to this helper is susceptible to change the underlaying
1579 * packet buffer. Therefore, at load time, all checks on pointers
1580 * previously done by the verifier are invalidated and must be
1581 * performed again, if the helper is used in combination with
1582 * direct packet access.
1583 * Return
1584 * 0 on success, or a negative error in case of failure.
1585 *
1586 * int bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
1587 * Description
1588 * Read the value of a perf event counter, and store it into *buf*
1589 * of size *buf_size*. This helper relies on a *map* of type
1590 * **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
1591 * counter is selected when *map* is updated with perf event file
1592 * descriptors. The *map* is an array whose size is the number of
1593 * available CPUs, and each cell contains a value relative to one
1594 * CPU. The value to retrieve is indicated by *flags*, that
1595 * contains the index of the CPU to look up, masked with
1596 * **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
1597 * **BPF_F_CURRENT_CPU** to indicate that the value for the
1598 * current CPU should be retrieved.
1599 *
1600 * This helper behaves in a way close to
1601 * **bpf_perf_event_read**\ () helper, save that instead of
1602 * just returning the value observed, it fills the *buf*
1603 * structure. This allows for additional data to be retrieved: in
1604 * particular, the enabled and running times (in *buf*\
1605 * **->enabled** and *buf*\ **->running**, respectively) are
1606 * copied. In general, **bpf_perf_event_read_value**\ () is
1607 * recommended over **bpf_perf_event_read**\ (), which has some
1608 * ABI issues and provides fewer functionalities.
1609 *
1610 * These values are interesting, because hardware PMU (Performance
1611 * Monitoring Unit) counters are limited resources. When there are
1612 * more PMU based perf events opened than available counters,
1613 * kernel will multiplex these events so each event gets certain
1614 * percentage (but not all) of the PMU time. In case that
1615 * multiplexing happens, the number of samples or counter value
1616 * will not reflect the case compared to when no multiplexing
1617 * occurs. This makes comparison between different runs difficult.
1618 * Typically, the counter value should be normalized before
1619 * comparing to other experiments. The usual normalization is done
1620 * as follows.
1621 *
1622 * ::
1623 *
1624 * normalized_counter = counter * t_enabled / t_running
1625 *
1626 * Where t_enabled is the time enabled for event and t_running is
1627 * the time running for event since last normalization. The
1628 * enabled and running times are accumulated since the perf event
1629 * open. To achieve scaling factor between two invocations of an
1630 * eBPF program, users can can use CPU id as the key (which is
1631 * typical for perf array usage model) to remember the previous
1632 * value and do the calculation inside the eBPF program.
1633 * Return
1634 * 0 on success, or a negative error in case of failure.
1635 *
1636 * int bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
1637 * Description
1638 * For en eBPF program attached to a perf event, retrieve the
1639 * value of the event counter associated to *ctx* and store it in
1640 * the structure pointed by *buf* and of size *buf_size*. Enabled
1641 * and running times are also stored in the structure (see
1642 * description of helper **bpf_perf_event_read_value**\ () for
1643 * more details).
1644 * Return
1645 * 0 on success, or a negative error in case of failure.
1646 *
1647 * int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
1648 * Description
1649 * Emulate a call to **getsockopt()** on the socket associated to
1650 * *bpf_socket*, which must be a full socket. The *level* at
1651 * which the option resides and the name *optname* of the option
1652 * must be specified, see **getsockopt(2)** for more information.
1653 * The retrieved value is stored in the structure pointed by
1654 * *opval* and of length *optlen*.
1655 *
1656 * This helper actually implements a subset of **getsockopt()**.
1657 * It supports the following *level*\ s:
1658 *
1659 * * **IPPROTO_TCP**, which supports *optname*
1660 * **TCP_CONGESTION**.
1661 * * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
1662 * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
1663 * Return
1664 * 0 on success, or a negative error in case of failure.
1665 *
1666 * int bpf_override_return(struct pt_reg *regs, u64 rc)
1667 * Description
1668 * Used for error injection, this helper uses kprobes to override
1669 * the return value of the probed function, and to set it to *rc*.
1670 * The first argument is the context *regs* on which the kprobe
1671 * works.
1672 *
1673 * This helper works by setting setting the PC (program counter)
1674 * to an override function which is run in place of the original
1675 * probed function. This means the probed function is not run at
1676 * all. The replacement function just returns with the required
1677 * value.
1678 *
1679 * This helper has security implications, and thus is subject to
1680 * restrictions. It is only available if the kernel was compiled
1681 * with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
1682 * option, and in this case it only works on functions tagged with
1683 * **ALLOW_ERROR_INJECTION** in the kernel code.
1684 *
1685 * Also, the helper is only available for the architectures having
1686 * the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
1687 * x86 architecture is the only one to support this feature.
1688 * Return
1689 * 0
1690 *
1691 * int bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
1692 * Description
1693 * Attempt to set the value of the **bpf_sock_ops_cb_flags** field
1694 * for the full TCP socket associated to *bpf_sock_ops* to
1695 * *argval*.
1696 *
1697 * The primary use of this field is to determine if there should
1698 * be calls to eBPF programs of type
1699 * **BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
1700 * code. A program of the same type can change its value, per
1701 * connection and as necessary, when the connection is
1702 * established. This field is directly accessible for reading, but
1703 * this helper must be used for updates in order to return an
1704 * error if an eBPF program tries to set a callback that is not
1705 * supported in the current kernel.
1706 *
1707 * The supported callback values that *argval* can combine are:
1708 *
1709 * * **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
1710 * * **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
1711 * * **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
1712 *
1713 * Here are some examples of where one could call such eBPF
1714 * program:
1715 *
1716 * * When RTO fires.
1717 * * When a packet is retransmitted.
1718 * * When the connection terminates.
1719 * * When a packet is sent.
1720 * * When a packet is received.
1721 * Return
1722 * Code **-EINVAL** if the socket is not a full TCP socket;
1723 * otherwise, a positive number containing the bits that could not
1724 * be set is returned (which comes down to 0 if all bits were set
1725 * as required).
1726 *
1727 * int bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
1728 * Description
1729 * This helper is used in programs implementing policies at the
1730 * socket level. If the message *msg* is allowed to pass (i.e. if
1731 * the verdict eBPF program returns **SK_PASS**), redirect it to
1732 * the socket referenced by *map* (of type
1733 * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
1734 * egress interfaces can be used for redirection. The
1735 * **BPF_F_INGRESS** value in *flags* is used to make the
1736 * distinction (ingress path is selected if the flag is present,
1737 * egress path otherwise). This is the only flag supported for now.
1738 * Return
1739 * **SK_PASS** on success, or **SK_DROP** on error.
1740 *
1741 * int bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
1742 * Description
1743 * For socket policies, apply the verdict of the eBPF program to
1744 * the next *bytes* (number of bytes) of message *msg*.
1745 *
1746 * For example, this helper can be used in the following cases:
1747 *
1748 * * A single **sendmsg**\ () or **sendfile**\ () system call
1749 * contains multiple logical messages that the eBPF program is
1750 * supposed to read and for which it should apply a verdict.
1751 * * An eBPF program only cares to read the first *bytes* of a
1752 * *msg*. If the message has a large payload, then setting up
1753 * and calling the eBPF program repeatedly for all bytes, even
1754 * though the verdict is already known, would create unnecessary
1755 * overhead.
1756 *
1757 * When called from within an eBPF program, the helper sets a
1758 * counter internal to the BPF infrastructure, that is used to
1759 * apply the last verdict to the next *bytes*. If *bytes* is
1760 * smaller than the current data being processed from a
1761 * **sendmsg**\ () or **sendfile**\ () system call, the first
1762 * *bytes* will be sent and the eBPF program will be re-run with
1763 * the pointer for start of data pointing to byte number *bytes*
1764 * **+ 1**. If *bytes* is larger than the current data being
1765 * processed, then the eBPF verdict will be applied to multiple
1766 * **sendmsg**\ () or **sendfile**\ () calls until *bytes* are
1767 * consumed.
1768 *
1769 * Note that if a socket closes with the internal counter holding
1770 * a non-zero value, this is not a problem because data is not
1771 * being buffered for *bytes* and is sent as it is received.
1772 * Return
1773 * 0
1774 *
1775 * int bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
1776 * Description
1777 * For socket policies, prevent the execution of the verdict eBPF
1778 * program for message *msg* until *bytes* (byte number) have been
1779 * accumulated.
1780 *
1781 * This can be used when one needs a specific number of bytes
1782 * before a verdict can be assigned, even if the data spans
1783 * multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
1784 * case would be a user calling **sendmsg**\ () repeatedly with
1785 * 1-byte long message segments. Obviously, this is bad for
1786 * performance, but it is still valid. If the eBPF program needs
1787 * *bytes* bytes to validate a header, this helper can be used to
1788 * prevent the eBPF program to be called again until *bytes* have
1789 * been accumulated.
1790 * Return
1791 * 0
1792 *
1793 * int bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
1794 * Description
1795 * For socket policies, pull in non-linear data from user space
1796 * for *msg* and set pointers *msg*\ **->data** and *msg*\
1797 * **->data_end** to *start* and *end* bytes offsets into *msg*,
1798 * respectively.
1799 *
1800 * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
1801 * *msg* it can only parse data that the (**data**, **data_end**)
1802 * pointers have already consumed. For **sendmsg**\ () hooks this
1803 * is likely the first scatterlist element. But for calls relying
1804 * on the **sendpage** handler (e.g. **sendfile**\ ()) this will
1805 * be the range (**0**, **0**) because the data is shared with
1806 * user space and by default the objective is to avoid allowing
1807 * user space to modify data while (or after) eBPF verdict is
1808 * being decided. This helper can be used to pull in data and to
1809 * set the start and end pointer to given values. Data will be
1810 * copied if necessary (i.e. if data was not linear and if start
1811 * and end pointers do not point to the same chunk).
1812 *
1813 * A call to this helper is susceptible to change the underlaying
1814 * packet buffer. Therefore, at load time, all checks on pointers
1815 * previously done by the verifier are invalidated and must be
1816 * performed again, if the helper is used in combination with
1817 * direct packet access.
1818 *
1819 * All values for *flags* are reserved for future usage, and must
1820 * be left at zero.
1821 * Return
1822 * 0 on success, or a negative error in case of failure.
1823 *
1824 * int bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
1825 * Description
1826 * Bind the socket associated to *ctx* to the address pointed by
1827 * *addr*, of length *addr_len*. This allows for making outgoing
1828 * connection from the desired IP address, which can be useful for
1829 * example when all processes inside a cgroup should use one
1830 * single IP address on a host that has multiple IP configured.
1831 *
1832 * This helper works for IPv4 and IPv6, TCP and UDP sockets. The
1833 * domain (*addr*\ **->sa_family**) must be **AF_INET** (or
1834 * **AF_INET6**). Looking for a free port to bind to can be
1835 * expensive, therefore binding to port is not permitted by the
1836 * helper: *addr*\ **->sin_port** (or **sin6_port**, respectively)
1837 * must be set to zero.
1838 * Return
1839 * 0 on success, or a negative error in case of failure.
1840 *
1841 * int bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
1842 * Description
1843 * Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
1844 * only possible to shrink the packet as of this writing,
1845 * therefore *delta* must be a negative integer.
1846 *
1847 * A call to this helper is susceptible to change the underlaying
1848 * packet buffer. Therefore, at load time, all checks on pointers
1849 * previously done by the verifier are invalidated and must be
1850 * performed again, if the helper is used in combination with
1851 * direct packet access.
1852 * Return
1853 * 0 on success, or a negative error in case of failure.
1854 *
1855 * int bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
1856 * Description
1857 * Retrieve the XFRM state (IP transform framework, see also
1858 * **ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
1859 *
1860 * The retrieved value is stored in the **struct bpf_xfrm_state**
1861 * pointed by *xfrm_state* and of length *size*.
1862 *
1863 * All values for *flags* are reserved for future usage, and must
1864 * be left at zero.
1865 *
1866 * This helper is available only if the kernel was compiled with
1867 * **CONFIG_XFRM** configuration option.
1868 * Return
1869 * 0 on success, or a negative error in case of failure.
1870 *
1871 * int bpf_get_stack(struct pt_regs *regs, void *buf, u32 size, u64 flags)
1872 * Description
1873 * Return a user or a kernel stack in bpf program provided buffer.
1874 * To achieve this, the helper needs *ctx*, which is a pointer
1875 * to the context on which the tracing program is executed.
1876 * To store the stacktrace, the bpf program provides *buf* with
1877 * a nonnegative *size*.
1878 *
1879 * The last argument, *flags*, holds the number of stack frames to
1880 * skip (from 0 to 255), masked with
1881 * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
1882 * the following flags:
1883 *
1884 * **BPF_F_USER_STACK**
1885 * Collect a user space stack instead of a kernel stack.
1886 * **BPF_F_USER_BUILD_ID**
1887 * Collect buildid+offset instead of ips for user stack,
1888 * only valid if **BPF_F_USER_STACK** is also specified.
1889 *
1890 * **bpf_get_stack**\ () can collect up to
1891 * **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
1892 * to sufficient large buffer size. Note that
1893 * this limit can be controlled with the **sysctl** program, and
1894 * that it should be manually increased in order to profile long
1895 * user stacks (such as stacks for Java programs). To do so, use:
1896 *
1897 * ::
1898 *
1899 * # sysctl kernel.perf_event_max_stack=<new value>
1900 * Return
1901 * A non-negative value equal to or less than *size* on success,
1902 * or a negative error in case of failure.
1903 *
1904 * int bpf_skb_load_bytes_relative(const struct sk_buff *skb, u32 offset, void *to, u32 len, u32 start_header)
1905 * Description
1906 * This helper is similar to **bpf_skb_load_bytes**\ () in that
1907 * it provides an easy way to load *len* bytes from *offset*
1908 * from the packet associated to *skb*, into the buffer pointed
1909 * by *to*. The difference to **bpf_skb_load_bytes**\ () is that
1910 * a fifth argument *start_header* exists in order to select a
1911 * base offset to start from. *start_header* can be one of:
1912 *
1913 * **BPF_HDR_START_MAC**
1914 * Base offset to load data from is *skb*'s mac header.
1915 * **BPF_HDR_START_NET**
1916 * Base offset to load data from is *skb*'s network header.
1917 *
1918 * In general, "direct packet access" is the preferred method to
1919 * access packet data, however, this helper is in particular useful
1920 * in socket filters where *skb*\ **->data** does not always point
1921 * to the start of the mac header and where "direct packet access"
1922 * is not available.
1923 * Return
1924 * 0 on success, or a negative error in case of failure.
1925 *
1926 * int bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
1927 * Description
1928 * Do FIB lookup in kernel tables using parameters in *params*.
1929 * If lookup is successful and result shows packet is to be
1930 * forwarded, the neighbor tables are searched for the nexthop.
1931 * If successful (ie., FIB lookup shows forwarding and nexthop
1932 * is resolved), the nexthop address is returned in ipv4_dst
1933 * or ipv6_dst based on family, smac is set to mac address of
1934 * egress device, dmac is set to nexthop mac address, rt_metric
1935 * is set to metric from route (IPv4/IPv6 only), and ifindex
1936 * is set to the device index of the nexthop from the FIB lookup.
1937 *
1938 * *plen* argument is the size of the passed in struct.
1939 * *flags* argument can be a combination of one or more of the
1940 * following values:
1941 *
1942 * **BPF_FIB_LOOKUP_DIRECT**
1943 * Do a direct table lookup vs full lookup using FIB
1944 * rules.
1945 * **BPF_FIB_LOOKUP_OUTPUT**
1946 * Perform lookup from an egress perspective (default is
1947 * ingress).
1948 *
1949 * *ctx* is either **struct xdp_md** for XDP programs or
1950 * **struct sk_buff** tc cls_act programs.
1951 * Return
1952 * * < 0 if any input argument is invalid
1953 * * 0 on success (packet is forwarded, nexthop neighbor exists)
1954 * * > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
1955 * packet is not forwarded or needs assist from full stack
1956 *
1957 * int bpf_sock_hash_update(struct bpf_sock_ops_kern *skops, struct bpf_map *map, void *key, u64 flags)
1958 * Description
1959 * Add an entry to, or update a sockhash *map* referencing sockets.
1960 * The *skops* is used as a new value for the entry associated to
1961 * *key*. *flags* is one of:
1962 *
1963 * **BPF_NOEXIST**
1964 * The entry for *key* must not exist in the map.
1965 * **BPF_EXIST**
1966 * The entry for *key* must already exist in the map.
1967 * **BPF_ANY**
1968 * No condition on the existence of the entry for *key*.
1969 *
1970 * If the *map* has eBPF programs (parser and verdict), those will
1971 * be inherited by the socket being added. If the socket is
1972 * already attached to eBPF programs, this results in an error.
1973 * Return
1974 * 0 on success, or a negative error in case of failure.
1975 *
1976 * int bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
1977 * Description
1978 * This helper is used in programs implementing policies at the
1979 * socket level. If the message *msg* is allowed to pass (i.e. if
1980 * the verdict eBPF program returns **SK_PASS**), redirect it to
1981 * the socket referenced by *map* (of type
1982 * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
1983 * egress interfaces can be used for redirection. The
1984 * **BPF_F_INGRESS** value in *flags* is used to make the
1985 * distinction (ingress path is selected if the flag is present,
1986 * egress path otherwise). This is the only flag supported for now.
1987 * Return
1988 * **SK_PASS** on success, or **SK_DROP** on error.
1989 *
1990 * int bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
1991 * Description
1992 * This helper is used in programs implementing policies at the
1993 * skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
1994 * if the verdeict eBPF program returns **SK_PASS**), redirect it
1995 * to the socket referenced by *map* (of type
1996 * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
1997 * egress interfaces can be used for redirection. The
1998 * **BPF_F_INGRESS** value in *flags* is used to make the
1999 * distinction (ingress path is selected if the flag is present,
2000 * egress otherwise). This is the only flag supported for now.
2001 * Return
2002 * **SK_PASS** on success, or **SK_DROP** on error.
2003 *
2004 * int bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
2005 * Description
2006 * Encapsulate the packet associated to *skb* within a Layer 3
2007 * protocol header. This header is provided in the buffer at
2008 * address *hdr*, with *len* its size in bytes. *type* indicates
2009 * the protocol of the header and can be one of:
2010 *
2011 * **BPF_LWT_ENCAP_SEG6**
2012 * IPv6 encapsulation with Segment Routing Header
2013 * (**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
2014 * the IPv6 header is computed by the kernel.
2015 * **BPF_LWT_ENCAP_SEG6_INLINE**
2016 * Only works if *skb* contains an IPv6 packet. Insert a
2017 * Segment Routing Header (**struct ipv6_sr_hdr**) inside
2018 * the IPv6 header.
2019 * **BPF_LWT_ENCAP_IP**
2020 * IP encapsulation (GRE/GUE/IPIP/etc). The outer header
2021 * must be IPv4 or IPv6, followed by zero or more
2022 * additional headers, up to LWT_BPF_MAX_HEADROOM total
2023 * bytes in all prepended headers. Please note that
2024 * if skb_is_gso(skb) is true, no more than two headers
2025 * can be prepended, and the inner header, if present,
2026 * should be either GRE or UDP/GUE.
2027 *
2028 * BPF_LWT_ENCAP_SEG6*** types can be called by bpf programs of
2029 * type BPF_PROG_TYPE_LWT_IN; BPF_LWT_ENCAP_IP type can be called
2030 * by bpf programs of types BPF_PROG_TYPE_LWT_IN and
2031 * BPF_PROG_TYPE_LWT_XMIT.
2032 *
2033 * A call to this helper is susceptible to change the underlaying
2034 * packet buffer. Therefore, at load time, all checks on pointers
2035 * previously done by the verifier are invalidated and must be
2036 * performed again, if the helper is used in combination with
2037 * direct packet access.
2038 * Return
2039 * 0 on success, or a negative error in case of failure.
2040 *
2041 * int bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
2042 * Description
2043 * Store *len* bytes from address *from* into the packet
2044 * associated to *skb*, at *offset*. Only the flags, tag and TLVs
2045 * inside the outermost IPv6 Segment Routing Header can be
2046 * modified through this helper.
2047 *
2048 * A call to this helper is susceptible to change the underlaying
2049 * packet buffer. Therefore, at load time, all checks on pointers
2050 * previously done by the verifier are invalidated and must be
2051 * performed again, if the helper is used in combination with
2052 * direct packet access.
2053 * Return
2054 * 0 on success, or a negative error in case of failure.
2055 *
2056 * int bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
2057 * Description
2058 * Adjust the size allocated to TLVs in the outermost IPv6
2059 * Segment Routing Header contained in the packet associated to
2060 * *skb*, at position *offset* by *delta* bytes. Only offsets
2061 * after the segments are accepted. *delta* can be as well
2062 * positive (growing) as negative (shrinking).
2063 *
2064 * A call to this helper is susceptible to change the underlaying
2065 * packet buffer. Therefore, at load time, all checks on pointers
2066 * previously done by the verifier are invalidated and must be
2067 * performed again, if the helper is used in combination with
2068 * direct packet access.
2069 * Return
2070 * 0 on success, or a negative error in case of failure.
2071 *
2072 * int bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
2073 * Description
2074 * Apply an IPv6 Segment Routing action of type *action* to the
2075 * packet associated to *skb*. Each action takes a parameter
2076 * contained at address *param*, and of length *param_len* bytes.
2077 * *action* can be one of:
2078 *
2079 * **SEG6_LOCAL_ACTION_END_X**
2080 * End.X action: Endpoint with Layer-3 cross-connect.
2081 * Type of *param*: **struct in6_addr**.
2082 * **SEG6_LOCAL_ACTION_END_T**
2083 * End.T action: Endpoint with specific IPv6 table lookup.
2084 * Type of *param*: **int**.
2085 * **SEG6_LOCAL_ACTION_END_B6**
2086 * End.B6 action: Endpoint bound to an SRv6 policy.
2087 * Type of param: **struct ipv6_sr_hdr**.
2088 * **SEG6_LOCAL_ACTION_END_B6_ENCAP**
2089 * End.B6.Encap action: Endpoint bound to an SRv6
2090 * encapsulation policy.
2091 * Type of param: **struct ipv6_sr_hdr**.
2092 *
2093 * A call to this helper is susceptible to change the underlaying
2094 * packet buffer. Therefore, at load time, all checks on pointers
2095 * previously done by the verifier are invalidated and must be
2096 * performed again, if the helper is used in combination with
2097 * direct packet access.
2098 * Return
2099 * 0 on success, or a negative error in case of failure.
2100 *
2101 * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
2102 * Description
2103 * This helper is used in programs implementing IR decoding, to
2104 * report a successfully decoded key press with *scancode*,
2105 * *toggle* value in the given *protocol*. The scancode will be
2106 * translated to a keycode using the rc keymap, and reported as
2107 * an input key down event. After a period a key up event is
2108 * generated. This period can be extended by calling either
2109 * **bpf_rc_keydown**\ () again with the same values, or calling
2110 * **bpf_rc_repeat**\ ().
2111 *
2112 * Some protocols include a toggle bit, in case the button was
2113 * released and pressed again between consecutive scancodes.
2114 *
2115 * The *ctx* should point to the lirc sample as passed into
2116 * the program.
2117 *
2118 * The *protocol* is the decoded protocol number (see
2119 * **enum rc_proto** for some predefined values).
2120 *
2121 * This helper is only available is the kernel was compiled with
2122 * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
2123 * "**y**".
2124 * Return
2125 * 0
2126 *
2127 * int bpf_rc_repeat(void *ctx)
2128 * Description
2129 * This helper is used in programs implementing IR decoding, to
2130 * report a successfully decoded repeat key message. This delays
2131 * the generation of a key up event for previously generated
2132 * key down event.
2133 *
2134 * Some IR protocols like NEC have a special IR message for
2135 * repeating last button, for when a button is held down.
2136 *
2137 * The *ctx* should point to the lirc sample as passed into
2138 * the program.
2139 *
2140 * This helper is only available is the kernel was compiled with
2141 * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
2142 * "**y**".
2143 * Return
2144 * 0
2145 *
2146 * uint64_t bpf_skb_cgroup_id(struct sk_buff *skb)
2147 * Description
2148 * Return the cgroup v2 id of the socket associated with the *skb*.
2149 * This is roughly similar to the **bpf_get_cgroup_classid**\ ()
2150 * helper for cgroup v1 by providing a tag resp. identifier that
2151 * can be matched on or used for map lookups e.g. to implement
2152 * policy. The cgroup v2 id of a given path in the hierarchy is
2153 * exposed in user space through the f_handle API in order to get
2154 * to the same 64-bit id.
2155 *
2156 * This helper can be used on TC egress path, but not on ingress,
2157 * and is available only if the kernel was compiled with the
2158 * **CONFIG_SOCK_CGROUP_DATA** configuration option.
2159 * Return
2160 * The id is returned or 0 in case the id could not be retrieved.
2161 *
2162 * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
2163 * Description
2164 * Return id of cgroup v2 that is ancestor of cgroup associated
2165 * with the *skb* at the *ancestor_level*. The root cgroup is at
2166 * *ancestor_level* zero and each step down the hierarchy
2167 * increments the level. If *ancestor_level* == level of cgroup
2168 * associated with *skb*, then return value will be same as that
2169 * of **bpf_skb_cgroup_id**\ ().
2170 *
2171 * The helper is useful to implement policies based on cgroups
2172 * that are upper in hierarchy than immediate cgroup associated
2173 * with *skb*.
2174 *
2175 * The format of returned id and helper limitations are same as in
2176 * **bpf_skb_cgroup_id**\ ().
2177 * Return
2178 * The id is returned or 0 in case the id could not be retrieved.
2179 *
2180 * u64 bpf_get_current_cgroup_id(void)
2181 * Return
2182 * A 64-bit integer containing the current cgroup id based
2183 * on the cgroup within which the current task is running.
2184 *
2185 * void* get_local_storage(void *map, u64 flags)
2186 * Description
2187 * Get the pointer to the local storage area.
2188 * The type and the size of the local storage is defined
2189 * by the *map* argument.
2190 * The *flags* meaning is specific for each map type,
2191 * and has to be 0 for cgroup local storage.
2192 *
2193 * Depending on the BPF program type, a local storage area
2194 * can be shared between multiple instances of the BPF program,
2195 * running simultaneously.
2196 *
2197 * A user should care about the synchronization by himself.
2198 * For example, by using the **BPF_STX_XADD** instruction to alter
2199 * the shared data.
2200 * Return
2201 * A pointer to the local storage area.
2202 *
2203 * int bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
2204 * Description
2205 * Select a **SO_REUSEPORT** socket from a
2206 * **BPF_MAP_TYPE_REUSEPORT_ARRAY** *map*.
2207 * It checks the selected socket is matching the incoming
2208 * request in the socket buffer.
2209 * Return
2210 * 0 on success, or a negative error in case of failure.
2211 *
2212 * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
2213 * Description
2214 * Look for TCP socket matching *tuple*, optionally in a child
2215 * network namespace *netns*. The return value must be checked,
2216 * and if non-**NULL**, released via **bpf_sk_release**\ ().
2217 *
2218 * The *ctx* should point to the context of the program, such as
2219 * the skb or socket (depending on the hook in use). This is used
2220 * to determine the base network namespace for the lookup.
2221 *
2222 * *tuple_size* must be one of:
2223 *
2224 * **sizeof**\ (*tuple*\ **->ipv4**)
2225 * Look for an IPv4 socket.
2226 * **sizeof**\ (*tuple*\ **->ipv6**)
2227 * Look for an IPv6 socket.
2228 *
2229 * If the *netns* is a negative signed 32-bit integer, then the
2230 * socket lookup table in the netns associated with the *ctx* will
2231 * will be used. For the TC hooks, this is the netns of the device
2232 * in the skb. For socket hooks, this is the netns of the socket.
2233 * If *netns* is any other signed 32-bit value greater than or
2234 * equal to zero then it specifies the ID of the netns relative to
2235 * the netns associated with the *ctx*. *netns* values beyond the
2236 * range of 32-bit integers are reserved for future use.
2237 *
2238 * All values for *flags* are reserved for future usage, and must
2239 * be left at zero.
2240 *
2241 * This helper is available only if the kernel was compiled with
2242 * **CONFIG_NET** configuration option.
2243 * Return
2244 * Pointer to **struct bpf_sock**, or **NULL** in case of failure.
2245 * For sockets with reuseport option, the **struct bpf_sock**
2246 * result is from **reuse->socks**\ [] using the hash of the tuple.
2247 *
2248 * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
2249 * Description
2250 * Look for UDP socket matching *tuple*, optionally in a child
2251 * network namespace *netns*. The return value must be checked,
2252 * and if non-**NULL**, released via **bpf_sk_release**\ ().
2253 *
2254 * The *ctx* should point to the context of the program, such as
2255 * the skb or socket (depending on the hook in use). This is used
2256 * to determine the base network namespace for the lookup.
2257 *
2258 * *tuple_size* must be one of:
2259 *
2260 * **sizeof**\ (*tuple*\ **->ipv4**)
2261 * Look for an IPv4 socket.
2262 * **sizeof**\ (*tuple*\ **->ipv6**)
2263 * Look for an IPv6 socket.
2264 *
2265 * If the *netns* is a negative signed 32-bit integer, then the
2266 * socket lookup table in the netns associated with the *ctx* will
2267 * will be used. For the TC hooks, this is the netns of the device
2268 * in the skb. For socket hooks, this is the netns of the socket.
2269 * If *netns* is any other signed 32-bit value greater than or
2270 * equal to zero then it specifies the ID of the netns relative to
2271 * the netns associated with the *ctx*. *netns* values beyond the
2272 * range of 32-bit integers are reserved for future use.
2273 *
2274 * All values for *flags* are reserved for future usage, and must
2275 * be left at zero.
2276 *
2277 * This helper is available only if the kernel was compiled with
2278 * **CONFIG_NET** configuration option.
2279 * Return
2280 * Pointer to **struct bpf_sock**, or **NULL** in case of failure.
2281 * For sockets with reuseport option, the **struct bpf_sock**
2282 * result is from **reuse->socks**\ [] using the hash of the tuple.
2283 *
2284 * int bpf_sk_release(struct bpf_sock *sock)
2285 * Description
2286 * Release the reference held by *sock*. *sock* must be a
2287 * non-**NULL** pointer that was returned from
2288 * **bpf_sk_lookup_xxx**\ ().
2289 * Return
2290 * 0 on success, or a negative error in case of failure.
2291 *
2292 * int bpf_map_pop_elem(struct bpf_map *map, void *value)
2293 * Description
2294 * Pop an element from *map*.
2295 * Return
2296 * 0 on success, or a negative error in case of failure.
2297 *
2298 * int bpf_map_peek_elem(struct bpf_map *map, void *value)
2299 * Description
2300 * Get an element from *map* without removing it.
2301 * Return
2302 * 0 on success, or a negative error in case of failure.
2303 *
2304 * int bpf_msg_push_data(struct sk_buff *skb, u32 start, u32 len, u64 flags)
2305 * Description
2306 * For socket policies, insert *len* bytes into *msg* at offset
2307 * *start*.
2308 *
2309 * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
2310 * *msg* it may want to insert metadata or options into the *msg*.
2311 * This can later be read and used by any of the lower layer BPF
2312 * hooks.
2313 *
2314 * This helper may fail if under memory pressure (a malloc
2315 * fails) in these cases BPF programs will get an appropriate
2316 * error and BPF programs will need to handle them.
2317 * Return
2318 * 0 on success, or a negative error in case of failure.
2319 *
2320 * int bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 pop, u64 flags)
2321 * Description
2322 * Will remove *pop* bytes from a *msg* starting at byte *start*.
2323 * This may result in **ENOMEM** errors under certain situations if
2324 * an allocation and copy are required due to a full ring buffer.
2325 * However, the helper will try to avoid doing the allocation
2326 * if possible. Other errors can occur if input parameters are
2327 * invalid either due to *start* byte not being valid part of *msg*
2328 * payload and/or *pop* value being to large.
2329 * Return
2330 * 0 on success, or a negative error in case of failure.
2331 *
2332 * int bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
2333 * Description
2334 * This helper is used in programs implementing IR decoding, to
2335 * report a successfully decoded pointer movement.
2336 *
2337 * The *ctx* should point to the lirc sample as passed into
2338 * the program.
2339 *
2340 * This helper is only available is the kernel was compiled with
2341 * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
2342 * "**y**".
2343 * Return
2344 * 0
2345 *
2346 * struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
2347 * Description
2348 * This helper gets a **struct bpf_sock** pointer such
2349 * that all the fields in bpf_sock can be accessed.
2350 * Return
2351 * A **struct bpf_sock** pointer on success, or NULL in
2352 * case of failure.
2353 *
2354 * struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
2355 * Description
2356 * This helper gets a **struct bpf_tcp_sock** pointer from a
2357 * **struct bpf_sock** pointer.
2358 *
2359 * Return
2360 * A **struct bpf_tcp_sock** pointer on success, or NULL in
2361 * case of failure.
2362 *
2363 * int bpf_skb_ecn_set_ce(struct sk_buf *skb)
2364 * Description
2365 * Sets ECN of IP header to ce (congestion encountered) if
2366 * current value is ect (ECN capable). Works with IPv6 and IPv4.
2367 * Return
2368 * 1 if set, 0 if not set.
2369 */
2370#define __BPF_FUNC_MAPPER(FN) \
2371 FN(unspec), \
2372 FN(map_lookup_elem), \
2373 FN(map_update_elem), \
2374 FN(map_delete_elem), \
2375 FN(probe_read), \
2376 FN(ktime_get_ns), \
2377 FN(trace_printk), \
2378 FN(get_prandom_u32), \
2379 FN(get_smp_processor_id), \
2380 FN(skb_store_bytes), \
2381 FN(l3_csum_replace), \
2382 FN(l4_csum_replace), \
2383 FN(tail_call), \
2384 FN(clone_redirect), \
2385 FN(get_current_pid_tgid), \
2386 FN(get_current_uid_gid), \
2387 FN(get_current_comm), \
2388 FN(get_cgroup_classid), \
2389 FN(skb_vlan_push), \
2390 FN(skb_vlan_pop), \
2391 FN(skb_get_tunnel_key), \
2392 FN(skb_set_tunnel_key), \
2393 FN(perf_event_read), \
2394 FN(redirect), \
2395 FN(get_route_realm), \
2396 FN(perf_event_output), \
2397 FN(skb_load_bytes), \
2398 FN(get_stackid), \
2399 FN(csum_diff), \
2400 FN(skb_get_tunnel_opt), \
2401 FN(skb_set_tunnel_opt), \
2402 FN(skb_change_proto), \
2403 FN(skb_change_type), \
2404 FN(skb_under_cgroup), \
2405 FN(get_hash_recalc), \
2406 FN(get_current_task), \
2407 FN(probe_write_user), \
2408 FN(current_task_under_cgroup), \
2409 FN(skb_change_tail), \
2410 FN(skb_pull_data), \
2411 FN(csum_update), \
2412 FN(set_hash_invalid), \
2413 FN(get_numa_node_id), \
2414 FN(skb_change_head), \
2415 FN(xdp_adjust_head), \
2416 FN(probe_read_str), \
2417 FN(get_socket_cookie), \
2418 FN(get_socket_uid), \
2419 FN(set_hash), \
2420 FN(setsockopt), \
2421 FN(skb_adjust_room), \
2422 FN(redirect_map), \
2423 FN(sk_redirect_map), \
2424 FN(sock_map_update), \
2425 FN(xdp_adjust_meta), \
2426 FN(perf_event_read_value), \
2427 FN(perf_prog_read_value), \
2428 FN(getsockopt), \
2429 FN(override_return), \
2430 FN(sock_ops_cb_flags_set), \
2431 FN(msg_redirect_map), \
2432 FN(msg_apply_bytes), \
2433 FN(msg_cork_bytes), \
2434 FN(msg_pull_data), \
2435 FN(bind), \
2436 FN(xdp_adjust_tail), \
2437 FN(skb_get_xfrm_state), \
2438 FN(get_stack), \
2439 FN(skb_load_bytes_relative), \
2440 FN(fib_lookup), \
2441 FN(sock_hash_update), \
2442 FN(msg_redirect_hash), \
2443 FN(sk_redirect_hash), \
2444 FN(lwt_push_encap), \
2445 FN(lwt_seg6_store_bytes), \
2446 FN(lwt_seg6_adjust_srh), \
2447 FN(lwt_seg6_action), \
2448 FN(rc_repeat), \
2449 FN(rc_keydown), \
2450 FN(skb_cgroup_id), \
2451 FN(get_current_cgroup_id), \
2452 FN(get_local_storage), \
2453 FN(sk_select_reuseport), \
2454 FN(skb_ancestor_cgroup_id), \
2455 FN(sk_lookup_tcp), \
2456 FN(sk_lookup_udp), \
2457 FN(sk_release), \
2458 FN(map_push_elem), \
2459 FN(map_pop_elem), \
2460 FN(map_peek_elem), \
2461 FN(msg_push_data), \
2462 FN(msg_pop_data), \
2463 FN(rc_pointer_rel), \
2464 FN(spin_lock), \
2465 FN(spin_unlock), \
2466 FN(sk_fullsock), \
2467 FN(tcp_sock), \
2468 FN(skb_ecn_set_ce),
2469
2470/* integer value in 'imm' field of BPF_CALL instruction selects which helper
2471 * function eBPF program intends to call
2472 */
2473#define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
2474enum bpf_func_id {
2475 __BPF_FUNC_MAPPER(__BPF_ENUM_FN)
2476 __BPF_FUNC_MAX_ID,
2477};
2478#undef __BPF_ENUM_FN
2479
2480/* All flags used by eBPF helper functions, placed here. */
2481
2482/* BPF_FUNC_skb_store_bytes flags. */
2483#define BPF_F_RECOMPUTE_CSUM (1ULL << 0)
2484#define BPF_F_INVALIDATE_HASH (1ULL << 1)
2485
2486/* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
2487 * First 4 bits are for passing the header field size.
2488 */
2489#define BPF_F_HDR_FIELD_MASK 0xfULL
2490
2491/* BPF_FUNC_l4_csum_replace flags. */
2492#define BPF_F_PSEUDO_HDR (1ULL << 4)
2493#define BPF_F_MARK_MANGLED_0 (1ULL << 5)
2494#define BPF_F_MARK_ENFORCE (1ULL << 6)
2495
2496/* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
2497#define BPF_F_INGRESS (1ULL << 0)
2498
2499/* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
2500#define BPF_F_TUNINFO_IPV6 (1ULL << 0)
2501
2502/* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
2503#define BPF_F_SKIP_FIELD_MASK 0xffULL
2504#define BPF_F_USER_STACK (1ULL << 8)
2505/* flags used by BPF_FUNC_get_stackid only. */
2506#define BPF_F_FAST_STACK_CMP (1ULL << 9)
2507#define BPF_F_REUSE_STACKID (1ULL << 10)
2508/* flags used by BPF_FUNC_get_stack only. */
2509#define BPF_F_USER_BUILD_ID (1ULL << 11)
2510
2511/* BPF_FUNC_skb_set_tunnel_key flags. */
2512#define BPF_F_ZERO_CSUM_TX (1ULL << 1)
2513#define BPF_F_DONT_FRAGMENT (1ULL << 2)
2514#define BPF_F_SEQ_NUMBER (1ULL << 3)
2515
2516/* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
2517 * BPF_FUNC_perf_event_read_value flags.
2518 */
2519#define BPF_F_INDEX_MASK 0xffffffffULL
2520#define BPF_F_CURRENT_CPU BPF_F_INDEX_MASK
2521/* BPF_FUNC_perf_event_output for sk_buff input context. */
2522#define BPF_F_CTXLEN_MASK (0xfffffULL << 32)
2523
2524/* Current network namespace */
2525#define BPF_F_CURRENT_NETNS (-1L)
2526
2527/* Mode for BPF_FUNC_skb_adjust_room helper. */
2528enum bpf_adj_room_mode {
2529 BPF_ADJ_ROOM_NET,
2530};
2531
2532/* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
2533enum bpf_hdr_start_off {
2534 BPF_HDR_START_MAC,
2535 BPF_HDR_START_NET,
2536};
2537
2538/* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
2539enum bpf_lwt_encap_mode {
2540 BPF_LWT_ENCAP_SEG6,
2541 BPF_LWT_ENCAP_SEG6_INLINE,
2542 BPF_LWT_ENCAP_IP,
2543};
2544
2545#define __bpf_md_ptr(type, name) \
2546union { \
2547 type name; \
2548 __u64 :64; \
2549} __attribute__((aligned(8)))
2550
2551/* user accessible mirror of in-kernel sk_buff.
2552 * new fields can only be added to the end of this structure
2553 */
2554struct __sk_buff {
2555 __u32 len;
2556 __u32 pkt_type;
2557 __u32 mark;
2558 __u32 queue_mapping;
2559 __u32 protocol;
2560 __u32 vlan_present;
2561 __u32 vlan_tci;
2562 __u32 vlan_proto;
2563 __u32 priority;
2564 __u32 ingress_ifindex;
2565 __u32 ifindex;
2566 __u32 tc_index;
2567 __u32 cb[5];
2568 __u32 hash;
2569 __u32 tc_classid;
2570 __u32 data;
2571 __u32 data_end;
2572 __u32 napi_id;
2573
2574 /* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
2575 __u32 family;
2576 __u32 remote_ip4; /* Stored in network byte order */
2577 __u32 local_ip4; /* Stored in network byte order */
2578 __u32 remote_ip6[4]; /* Stored in network byte order */
2579 __u32 local_ip6[4]; /* Stored in network byte order */
2580 __u32 remote_port; /* Stored in network byte order */
2581 __u32 local_port; /* stored in host byte order */
2582 /* ... here. */
2583
2584 __u32 data_meta;
2585 __bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
2586 __u64 tstamp;
2587 __u32 wire_len;
2588 __u32 gso_segs;
2589 __bpf_md_ptr(struct bpf_sock *, sk);
2590};
2591
2592struct bpf_tunnel_key {
2593 __u32 tunnel_id;
2594 union {
2595 __u32 remote_ipv4;
2596 __u32 remote_ipv6[4];
2597 };
2598 __u8 tunnel_tos;
2599 __u8 tunnel_ttl;
2600 __u16 tunnel_ext; /* Padding, future use. */
2601 __u32 tunnel_label;
2602};
2603
2604/* user accessible mirror of in-kernel xfrm_state.
2605 * new fields can only be added to the end of this structure
2606 */
2607struct bpf_xfrm_state {
2608 __u32 reqid;
2609 __u32 spi; /* Stored in network byte order */
2610 __u16 family;
2611 __u16 ext; /* Padding, future use. */
2612 union {
2613 __u32 remote_ipv4; /* Stored in network byte order */
2614 __u32 remote_ipv6[4]; /* Stored in network byte order */
2615 };
2616};
2617
2618/* Generic BPF return codes which all BPF program types may support.
2619 * The values are binary compatible with their TC_ACT_* counter-part to
2620 * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
2621 * programs.
2622 *
2623 * XDP is handled seprately, see XDP_*.
2624 */
2625enum bpf_ret_code {
2626 BPF_OK = 0,
2627 /* 1 reserved */
2628 BPF_DROP = 2,
2629 /* 3-6 reserved */
2630 BPF_REDIRECT = 7,
2631 /* >127 are reserved for prog type specific return codes.
2632 *
2633 * BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and
2634 * BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been
2635 * changed and should be routed based on its new L3 header.
2636 * (This is an L3 redirect, as opposed to L2 redirect
2637 * represented by BPF_REDIRECT above).
2638 */
2639 BPF_LWT_REROUTE = 128,
2640};
2641
2642struct bpf_sock {
2643 __u32 bound_dev_if;
2644 __u32 family;
2645 __u32 type;
2646 __u32 protocol;
2647 __u32 mark;
2648 __u32 priority;
2649 /* IP address also allows 1 and 2 bytes access */
2650 __u32 src_ip4;
2651 __u32 src_ip6[4];
2652 __u32 src_port; /* host byte order */
2653 __u32 dst_port; /* network byte order */
2654 __u32 dst_ip4;
2655 __u32 dst_ip6[4];
2656 __u32 state;
2657};
2658
2659struct bpf_tcp_sock {
2660 __u32 snd_cwnd; /* Sending congestion window */
2661 __u32 srtt_us; /* smoothed round trip time << 3 in usecs */
2662 __u32 rtt_min;
2663 __u32 snd_ssthresh; /* Slow start size threshold */
2664 __u32 rcv_nxt; /* What we want to receive next */
2665 __u32 snd_nxt; /* Next sequence we send */
2666 __u32 snd_una; /* First byte we want an ack for */
2667 __u32 mss_cache; /* Cached effective mss, not including SACKS */
2668 __u32 ecn_flags; /* ECN status bits. */
2669 __u32 rate_delivered; /* saved rate sample: packets delivered */
2670 __u32 rate_interval_us; /* saved rate sample: time elapsed */
2671 __u32 packets_out; /* Packets which are "in flight" */
2672 __u32 retrans_out; /* Retransmitted packets out */
2673 __u32 total_retrans; /* Total retransmits for entire connection */
2674 __u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn
2675 * total number of segments in.
2676 */
2677 __u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn
2678 * total number of data segments in.
2679 */
2680 __u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut
2681 * The total number of segments sent.
2682 */
2683 __u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut
2684 * total number of data segments sent.
2685 */
2686 __u32 lost_out; /* Lost packets */
2687 __u32 sacked_out; /* SACK'd packets */
2688 __u64 bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived
2689 * sum(delta(rcv_nxt)), or how many bytes
2690 * were acked.
2691 */
2692 __u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked
2693 * sum(delta(snd_una)), or how many bytes
2694 * were acked.
2695 */
2696};
2697
2698struct bpf_sock_tuple {
2699 union {
2700 struct {
2701 __be32 saddr;
2702 __be32 daddr;
2703 __be16 sport;
2704 __be16 dport;
2705 } ipv4;
2706 struct {
2707 __be32 saddr[4];
2708 __be32 daddr[4];
2709 __be16 sport;
2710 __be16 dport;
2711 } ipv6;
2712 };
2713};
2714
2715#define XDP_PACKET_HEADROOM 256
2716
2717/* User return codes for XDP prog type.
2718 * A valid XDP program must return one of these defined values. All other
2719 * return codes are reserved for future use. Unknown return codes will
2720 * result in packet drops and a warning via bpf_warn_invalid_xdp_action().
2721 */
2722enum xdp_action {
2723 XDP_ABORTED = 0,
2724 XDP_DROP,
2725 XDP_PASS,
2726 XDP_TX,
2727 XDP_REDIRECT,
2728};
2729
2730/* user accessible metadata for XDP packet hook
2731 * new fields must be added to the end of this structure
2732 */
2733struct xdp_md {
2734 __u32 data;
2735 __u32 data_end;
2736 __u32 data_meta;
2737 /* Below access go through struct xdp_rxq_info */
2738 __u32 ingress_ifindex; /* rxq->dev->ifindex */
2739 __u32 rx_queue_index; /* rxq->queue_index */
2740};
2741
2742enum sk_action {
2743 SK_DROP = 0,
2744 SK_PASS,
2745};
2746
2747/* user accessible metadata for SK_MSG packet hook, new fields must
2748 * be added to the end of this structure
2749 */
2750struct sk_msg_md {
2751 __bpf_md_ptr(void *, data);
2752 __bpf_md_ptr(void *, data_end);
2753
2754 __u32 family;
2755 __u32 remote_ip4; /* Stored in network byte order */
2756 __u32 local_ip4; /* Stored in network byte order */
2757 __u32 remote_ip6[4]; /* Stored in network byte order */
2758 __u32 local_ip6[4]; /* Stored in network byte order */
2759 __u32 remote_port; /* Stored in network byte order */
2760 __u32 local_port; /* stored in host byte order */
2761 __u32 size; /* Total size of sk_msg */
2762};
2763
2764struct sk_reuseport_md {
2765 /*
2766 * Start of directly accessible data. It begins from
2767 * the tcp/udp header.
2768 */
2769 __bpf_md_ptr(void *, data);
2770 /* End of directly accessible data */
2771 __bpf_md_ptr(void *, data_end);
2772 /*
2773 * Total length of packet (starting from the tcp/udp header).
2774 * Note that the directly accessible bytes (data_end - data)
2775 * could be less than this "len". Those bytes could be
2776 * indirectly read by a helper "bpf_skb_load_bytes()".
2777 */
2778 __u32 len;
2779 /*
2780 * Eth protocol in the mac header (network byte order). e.g.
2781 * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
2782 */
2783 __u32 eth_protocol;
2784 __u32 ip_protocol; /* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
2785 __u32 bind_inany; /* Is sock bound to an INANY address? */
2786 __u32 hash; /* A hash of the packet 4 tuples */
2787};
2788
2789#define BPF_TAG_SIZE 8
2790
2791struct bpf_prog_info {
2792 __u32 type;
2793 __u32 id;
2794 __u8 tag[BPF_TAG_SIZE];
2795 __u32 jited_prog_len;
2796 __u32 xlated_prog_len;
2797 __aligned_u64 jited_prog_insns;
2798 __aligned_u64 xlated_prog_insns;
2799 __u64 load_time; /* ns since boottime */
2800 __u32 created_by_uid;
2801 __u32 nr_map_ids;
2802 __aligned_u64 map_ids;
2803 char name[BPF_OBJ_NAME_LEN];
2804 __u32 ifindex;
2805 __u32 gpl_compatible:1;
2806 __u64 netns_dev;
2807 __u64 netns_ino;
2808 __u32 nr_jited_ksyms;
2809 __u32 nr_jited_func_lens;
2810 __aligned_u64 jited_ksyms;
2811 __aligned_u64 jited_func_lens;
2812 __u32 btf_id;
2813 __u32 func_info_rec_size;
2814 __aligned_u64 func_info;
2815 __u32 nr_func_info;
2816 __u32 nr_line_info;
2817 __aligned_u64 line_info;
2818 __aligned_u64 jited_line_info;
2819 __u32 nr_jited_line_info;
2820 __u32 line_info_rec_size;
2821 __u32 jited_line_info_rec_size;
2822 __u32 nr_prog_tags;
2823 __aligned_u64 prog_tags;
2824 __u64 run_time_ns;
2825 __u64 run_cnt;
2826} __attribute__((aligned(8)));
2827
2828struct bpf_map_info {
2829 __u32 type;
2830 __u32 id;
2831 __u32 key_size;
2832 __u32 value_size;
2833 __u32 max_entries;
2834 __u32 map_flags;
2835 char name[BPF_OBJ_NAME_LEN];
2836 __u32 ifindex;
2837 __u32 :32;
2838 __u64 netns_dev;
2839 __u64 netns_ino;
2840 __u32 btf_id;
2841 __u32 btf_key_type_id;
2842 __u32 btf_value_type_id;
2843} __attribute__((aligned(8)));
2844
2845struct bpf_btf_info {
2846 __aligned_u64 btf;
2847 __u32 btf_size;
2848 __u32 id;
2849} __attribute__((aligned(8)));
2850
2851/* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
2852 * by user and intended to be used by socket (e.g. to bind to, depends on
2853 * attach attach type).
2854 */
2855struct bpf_sock_addr {
2856 __u32 user_family; /* Allows 4-byte read, but no write. */
2857 __u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write.
2858 * Stored in network byte order.
2859 */
2860 __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write.
2861 * Stored in network byte order.
2862 */
2863 __u32 user_port; /* Allows 4-byte read and write.
2864 * Stored in network byte order
2865 */
2866 __u32 family; /* Allows 4-byte read, but no write */
2867 __u32 type; /* Allows 4-byte read, but no write */
2868 __u32 protocol; /* Allows 4-byte read, but no write */
2869 __u32 msg_src_ip4; /* Allows 1,2,4-byte read an 4-byte write.
2870 * Stored in network byte order.
2871 */
2872 __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write.
2873 * Stored in network byte order.
2874 */
2875};
2876
2877/* User bpf_sock_ops struct to access socket values and specify request ops
2878 * and their replies.
2879 * Some of this fields are in network (bigendian) byte order and may need
2880 * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
2881 * New fields can only be added at the end of this structure
2882 */
2883struct bpf_sock_ops {
2884 __u32 op;
2885 union {
2886 __u32 args[4]; /* Optionally passed to bpf program */
2887 __u32 reply; /* Returned by bpf program */
2888 __u32 replylong[4]; /* Optionally returned by bpf prog */
2889 };
2890 __u32 family;
2891 __u32 remote_ip4; /* Stored in network byte order */
2892 __u32 local_ip4; /* Stored in network byte order */
2893 __u32 remote_ip6[4]; /* Stored in network byte order */
2894 __u32 local_ip6[4]; /* Stored in network byte order */
2895 __u32 remote_port; /* Stored in network byte order */
2896 __u32 local_port; /* stored in host byte order */
2897 __u32 is_fullsock; /* Some TCP fields are only valid if
2898 * there is a full socket. If not, the
2899 * fields read as zero.
2900 */
2901 __u32 snd_cwnd;
2902 __u32 srtt_us; /* Averaged RTT << 3 in usecs */
2903 __u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
2904 __u32 state;
2905 __u32 rtt_min;
2906 __u32 snd_ssthresh;
2907 __u32 rcv_nxt;
2908 __u32 snd_nxt;
2909 __u32 snd_una;
2910 __u32 mss_cache;
2911 __u32 ecn_flags;
2912 __u32 rate_delivered;
2913 __u32 rate_interval_us;
2914 __u32 packets_out;
2915 __u32 retrans_out;
2916 __u32 total_retrans;
2917 __u32 segs_in;
2918 __u32 data_segs_in;
2919 __u32 segs_out;
2920 __u32 data_segs_out;
2921 __u32 lost_out;
2922 __u32 sacked_out;
2923 __u32 sk_txhash;
2924 __u64 bytes_received;
2925 __u64 bytes_acked;
2926};
2927
2928/* Definitions for bpf_sock_ops_cb_flags */
2929#define BPF_SOCK_OPS_RTO_CB_FLAG (1<<0)
2930#define BPF_SOCK_OPS_RETRANS_CB_FLAG (1<<1)
2931#define BPF_SOCK_OPS_STATE_CB_FLAG (1<<2)
2932#define BPF_SOCK_OPS_ALL_CB_FLAGS 0x7 /* Mask of all currently
2933 * supported cb flags
2934 */
2935
2936/* List of known BPF sock_ops operators.
2937 * New entries can only be added at the end
2938 */
2939enum {
2940 BPF_SOCK_OPS_VOID,
2941 BPF_SOCK_OPS_TIMEOUT_INIT, /* Should return SYN-RTO value to use or
2942 * -1 if default value should be used
2943 */
2944 BPF_SOCK_OPS_RWND_INIT, /* Should return initial advertized
2945 * window (in packets) or -1 if default
2946 * value should be used
2947 */
2948 BPF_SOCK_OPS_TCP_CONNECT_CB, /* Calls BPF program right before an
2949 * active connection is initialized
2950 */
2951 BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB, /* Calls BPF program when an
2952 * active connection is
2953 * established
2954 */
2955 BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, /* Calls BPF program when a
2956 * passive connection is
2957 * established
2958 */
2959 BPF_SOCK_OPS_NEEDS_ECN, /* If connection's congestion control
2960 * needs ECN
2961 */
2962 BPF_SOCK_OPS_BASE_RTT, /* Get base RTT. The correct value is
2963 * based on the path and may be
2964 * dependent on the congestion control
2965 * algorithm. In general it indicates
2966 * a congestion threshold. RTTs above
2967 * this indicate congestion
2968 */
2969 BPF_SOCK_OPS_RTO_CB, /* Called when an RTO has triggered.
2970 * Arg1: value of icsk_retransmits
2971 * Arg2: value of icsk_rto
2972 * Arg3: whether RTO has expired
2973 */
2974 BPF_SOCK_OPS_RETRANS_CB, /* Called when skb is retransmitted.
2975 * Arg1: sequence number of 1st byte
2976 * Arg2: # segments
2977 * Arg3: return value of
2978 * tcp_transmit_skb (0 => success)
2979 */
2980 BPF_SOCK_OPS_STATE_CB, /* Called when TCP changes state.
2981 * Arg1: old_state
2982 * Arg2: new_state
2983 */
2984 BPF_SOCK_OPS_TCP_LISTEN_CB, /* Called on listen(2), right after
2985 * socket transition to LISTEN state.
2986 */
2987};
2988
2989/* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
2990 * changes between the TCP and BPF versions. Ideally this should never happen.
2991 * If it does, we need to add code to convert them before calling
2992 * the BPF sock_ops function.
2993 */
2994enum {
2995 BPF_TCP_ESTABLISHED = 1,
2996 BPF_TCP_SYN_SENT,
2997 BPF_TCP_SYN_RECV,
2998 BPF_TCP_FIN_WAIT1,
2999 BPF_TCP_FIN_WAIT2,
3000 BPF_TCP_TIME_WAIT,
3001 BPF_TCP_CLOSE,
3002 BPF_TCP_CLOSE_WAIT,
3003 BPF_TCP_LAST_ACK,
3004 BPF_TCP_LISTEN,
3005 BPF_TCP_CLOSING, /* Now a valid state */
3006 BPF_TCP_NEW_SYN_RECV,
3007
3008 BPF_TCP_MAX_STATES /* Leave at the end! */
3009};
3010
3011#define TCP_BPF_IW 1001 /* Set TCP initial congestion window */
3012#define TCP_BPF_SNDCWND_CLAMP 1002 /* Set sndcwnd_clamp */
3013
3014struct bpf_perf_event_value {
3015 __u64 counter;
3016 __u64 enabled;
3017 __u64 running;
3018};
3019
3020#define BPF_DEVCG_ACC_MKNOD (1ULL << 0)
3021#define BPF_DEVCG_ACC_READ (1ULL << 1)
3022#define BPF_DEVCG_ACC_WRITE (1ULL << 2)
3023
3024#define BPF_DEVCG_DEV_BLOCK (1ULL << 0)
3025#define BPF_DEVCG_DEV_CHAR (1ULL << 1)
3026
3027struct bpf_cgroup_dev_ctx {
3028 /* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
3029 __u32 access_type;
3030 __u32 major;
3031 __u32 minor;
3032};
3033
3034struct bpf_raw_tracepoint_args {
3035 __u64 args[0];
3036};
3037
3038/* DIRECT: Skip the FIB rules and go to FIB table associated with device
3039 * OUTPUT: Do lookup from egress perspective; default is ingress
3040 */
3041#define BPF_FIB_LOOKUP_DIRECT BIT(0)
3042#define BPF_FIB_LOOKUP_OUTPUT BIT(1)
3043
3044enum {
3045 BPF_FIB_LKUP_RET_SUCCESS, /* lookup successful */
3046 BPF_FIB_LKUP_RET_BLACKHOLE, /* dest is blackholed; can be dropped */
3047 BPF_FIB_LKUP_RET_UNREACHABLE, /* dest is unreachable; can be dropped */
3048 BPF_FIB_LKUP_RET_PROHIBIT, /* dest not allowed; can be dropped */
3049 BPF_FIB_LKUP_RET_NOT_FWDED, /* packet is not forwarded */
3050 BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
3051 BPF_FIB_LKUP_RET_UNSUPP_LWT, /* fwd requires encapsulation */
3052 BPF_FIB_LKUP_RET_NO_NEIGH, /* no neighbor entry for nh */
3053 BPF_FIB_LKUP_RET_FRAG_NEEDED, /* fragmentation required to fwd */
3054};
3055
3056struct bpf_fib_lookup {
3057 /* input: network family for lookup (AF_INET, AF_INET6)
3058 * output: network family of egress nexthop
3059 */
3060 __u8 family;
3061
3062 /* set if lookup is to consider L4 data - e.g., FIB rules */
3063 __u8 l4_protocol;
3064 __be16 sport;
3065 __be16 dport;
3066
3067 /* total length of packet from network header - used for MTU check */
3068 __u16 tot_len;
3069
3070 /* input: L3 device index for lookup
3071 * output: device index from FIB lookup
3072 */
3073 __u32 ifindex;
3074
3075 union {
3076 /* inputs to lookup */
3077 __u8 tos; /* AF_INET */
3078 __be32 flowinfo; /* AF_INET6, flow_label + priority */
3079
3080 /* output: metric of fib result (IPv4/IPv6 only) */
3081 __u32 rt_metric;
3082 };
3083
3084 union {
3085 __be32 ipv4_src;
3086 __u32 ipv6_src[4]; /* in6_addr; network order */
3087 };
3088
3089 /* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
3090 * network header. output: bpf_fib_lookup sets to gateway address
3091 * if FIB lookup returns gateway route
3092 */
3093 union {
3094 __be32 ipv4_dst;
3095 __u32 ipv6_dst[4]; /* in6_addr; network order */
3096 };
3097
3098 /* output */
3099 __be16 h_vlan_proto;
3100 __be16 h_vlan_TCI;
3101 __u8 smac[6]; /* ETH_ALEN */
3102 __u8 dmac[6]; /* ETH_ALEN */
3103};
3104
3105enum bpf_task_fd_type {
3106 BPF_FD_TYPE_RAW_TRACEPOINT, /* tp name */
3107 BPF_FD_TYPE_TRACEPOINT, /* tp name */
3108 BPF_FD_TYPE_KPROBE, /* (symbol + offset) or addr */
3109 BPF_FD_TYPE_KRETPROBE, /* (symbol + offset) or addr */
3110 BPF_FD_TYPE_UPROBE, /* filename + offset */
3111 BPF_FD_TYPE_URETPROBE, /* filename + offset */
3112};
3113
3114struct bpf_flow_keys {
3115 __u16 nhoff;
3116 __u16 thoff;
3117 __u16 addr_proto; /* ETH_P_* of valid addrs */
3118 __u8 is_frag;
3119 __u8 is_first_frag;
3120 __u8 is_encap;
3121 __u8 ip_proto;
3122 __be16 n_proto;
3123 __be16 sport;
3124 __be16 dport;
3125 union {
3126 struct {
3127 __be32 ipv4_src;
3128 __be32 ipv4_dst;
3129 };
3130 struct {
3131 __u32 ipv6_src[4]; /* in6_addr; network order */
3132 __u32 ipv6_dst[4]; /* in6_addr; network order */
3133 };
3134 };
3135};
3136
3137struct bpf_func_info {
3138 __u32 insn_off;
3139 __u32 type_id;
3140};
3141
3142#define BPF_LINE_INFO_LINE_NUM(line_col) ((line_col) >> 10)
3143#define BPF_LINE_INFO_LINE_COL(line_col) ((line_col) & 0x3ff)
3144
3145struct bpf_line_info {
3146 __u32 insn_off;
3147 __u32 file_name_off;
3148 __u32 line_off;
3149 __u32 line_col;
3150};
3151
3152struct bpf_spin_lock {
3153 __u32 val;
3154};
3155#endif /* _UAPI__LINUX_BPF_H__ */
3156