1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
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.
8 #ifndef _UAPI__LINUX_BPF_H__
9 #define _UAPI__LINUX_BPF_H__
11 #include <linux/types.h>
12 #include <linux/bpf_common.h>
14 /* Extended instruction set based on top of classic BPF */
16 /* instruction classes */
17 #define BPF_ALU64 0x07 /* alu mode in double word width */
20 #define BPF_DW 0x18 /* double word (64-bit) */
21 #define BPF_XADD 0xc0 /* exclusive add */
24 #define BPF_MOV 0xb0 /* mov reg to reg */
25 #define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */
27 /* change endianness of a register */
28 #define BPF_END 0xd0 /* flags for endianness conversion: */
29 #define BPF_TO_LE 0x00 /* convert to little-endian */
30 #define BPF_TO_BE 0x08 /* convert to big-endian */
31 #define BPF_FROM_LE BPF_TO_LE
32 #define BPF_FROM_BE BPF_TO_BE
35 #define BPF_JNE 0x50 /* jump != */
36 #define BPF_JLT 0xa0 /* LT is unsigned, '<' */
37 #define BPF_JLE 0xb0 /* LE is unsigned, '<=' */
38 #define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */
39 #define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */
40 #define BPF_JSLT 0xc0 /* SLT is signed, '<' */
41 #define BPF_JSLE 0xd0 /* SLE is signed, '<=' */
42 #define BPF_CALL 0x80 /* function call */
43 #define BPF_EXIT 0x90 /* function return */
45 /* Register numbers */
61 /* BPF has 10 general purpose 64-bit registers and stack frame. */
62 #define MAX_BPF_REG __MAX_BPF_REG
65 __u8 code; /* opcode */
66 __u8 dst_reg:4; /* dest register */
67 __u8 src_reg:4; /* source register */
68 __s16 off; /* signed offset */
69 __s32 imm; /* signed immediate constant */
72 /* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
73 struct bpf_lpm_trie_key {
74 __u32 prefixlen; /* up to 32 for AF_INET, 128 for AF_INET6 */
75 __u8 data[0]; /* Arbitrary size */
78 struct bpf_cgroup_storage_key {
79 __u64 cgroup_inode_id; /* cgroup inode id */
80 __u32 attach_type; /* program attach type */
83 /* BPF syscall commands, see bpf(2) man-page for details. */
98 BPF_PROG_GET_FD_BY_ID,
100 BPF_OBJ_GET_INFO_BY_FD,
102 BPF_RAW_TRACEPOINT_OPEN,
104 BPF_BTF_GET_FD_BY_ID,
106 BPF_MAP_LOOKUP_AND_DELETE_ELEM,
113 BPF_MAP_TYPE_PROG_ARRAY,
114 BPF_MAP_TYPE_PERF_EVENT_ARRAY,
115 BPF_MAP_TYPE_PERCPU_HASH,
116 BPF_MAP_TYPE_PERCPU_ARRAY,
117 BPF_MAP_TYPE_STACK_TRACE,
118 BPF_MAP_TYPE_CGROUP_ARRAY,
119 BPF_MAP_TYPE_LRU_HASH,
120 BPF_MAP_TYPE_LRU_PERCPU_HASH,
121 BPF_MAP_TYPE_LPM_TRIE,
122 BPF_MAP_TYPE_ARRAY_OF_MAPS,
123 BPF_MAP_TYPE_HASH_OF_MAPS,
125 BPF_MAP_TYPE_SOCKMAP,
128 BPF_MAP_TYPE_SOCKHASH,
129 BPF_MAP_TYPE_CGROUP_STORAGE,
130 BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
131 BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
137 BPF_PROG_TYPE_UNSPEC,
138 BPF_PROG_TYPE_SOCKET_FILTER,
139 BPF_PROG_TYPE_KPROBE,
140 BPF_PROG_TYPE_SCHED_CLS,
141 BPF_PROG_TYPE_SCHED_ACT,
142 BPF_PROG_TYPE_TRACEPOINT,
144 BPF_PROG_TYPE_PERF_EVENT,
145 BPF_PROG_TYPE_CGROUP_SKB,
146 BPF_PROG_TYPE_CGROUP_SOCK,
147 BPF_PROG_TYPE_LWT_IN,
148 BPF_PROG_TYPE_LWT_OUT,
149 BPF_PROG_TYPE_LWT_XMIT,
150 BPF_PROG_TYPE_SOCK_OPS,
151 BPF_PROG_TYPE_SK_SKB,
152 BPF_PROG_TYPE_CGROUP_DEVICE,
153 BPF_PROG_TYPE_SK_MSG,
154 BPF_PROG_TYPE_RAW_TRACEPOINT,
155 BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
156 BPF_PROG_TYPE_LWT_SEG6LOCAL,
157 BPF_PROG_TYPE_LIRC_MODE2,
158 BPF_PROG_TYPE_SK_REUSEPORT,
159 BPF_PROG_TYPE_FLOW_DISSECTOR,
162 enum bpf_attach_type {
163 BPF_CGROUP_INET_INGRESS,
164 BPF_CGROUP_INET_EGRESS,
165 BPF_CGROUP_INET_SOCK_CREATE,
167 BPF_SK_SKB_STREAM_PARSER,
168 BPF_SK_SKB_STREAM_VERDICT,
171 BPF_CGROUP_INET4_BIND,
172 BPF_CGROUP_INET6_BIND,
173 BPF_CGROUP_INET4_CONNECT,
174 BPF_CGROUP_INET6_CONNECT,
175 BPF_CGROUP_INET4_POST_BIND,
176 BPF_CGROUP_INET6_POST_BIND,
177 BPF_CGROUP_UDP4_SENDMSG,
178 BPF_CGROUP_UDP6_SENDMSG,
181 __MAX_BPF_ATTACH_TYPE
184 #define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
186 /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
188 * NONE(default): No further bpf programs allowed in the subtree.
190 * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
191 * the program in this cgroup yields to sub-cgroup program.
193 * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
194 * that cgroup program gets run in addition to the program in this cgroup.
196 * Only one program is allowed to be attached to a cgroup with
197 * NONE or BPF_F_ALLOW_OVERRIDE flag.
198 * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
199 * release old program and attach the new one. Attach flags has to match.
201 * Multiple programs are allowed to be attached to a cgroup with
202 * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
203 * (those that were attached first, run first)
204 * The programs of sub-cgroup are executed first, then programs of
205 * this cgroup and then programs of parent cgroup.
206 * When children program makes decision (like picking TCP CA or sock bind)
207 * parent program has a chance to override it.
209 * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
210 * A cgroup with NONE doesn't allow any programs in sub-cgroups.
212 * cgrp1 (MULTI progs A, B) ->
213 * cgrp2 (OVERRIDE prog C) ->
214 * cgrp3 (MULTI prog D) ->
215 * cgrp4 (OVERRIDE prog E) ->
216 * cgrp5 (NONE prog F)
217 * the event in cgrp5 triggers execution of F,D,A,B in that order.
218 * if prog F is detached, the execution is E,D,A,B
219 * if prog F and D are detached, the execution is E,A,B
220 * if prog F, E and D are detached, the execution is C,A,B
222 * All eligible programs are executed regardless of return code from
225 #define BPF_F_ALLOW_OVERRIDE (1U << 0)
226 #define BPF_F_ALLOW_MULTI (1U << 1)
228 /* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
229 * verifier will perform strict alignment checking as if the kernel
230 * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
231 * and NET_IP_ALIGN defined to 2.
233 #define BPF_F_STRICT_ALIGNMENT (1U << 0)
235 /* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
236 * verifier will allow any alignment whatsoever. On platforms
237 * with strict alignment requirements for loads ands stores (such
238 * as sparc and mips) the verifier validates that all loads and
239 * stores provably follow this requirement. This flag turns that
240 * checking and enforcement off.
242 * It is mostly used for testing when we want to validate the
243 * context and memory access aspects of the verifier, but because
244 * of an unaligned access the alignment check would trigger before
245 * the one we are interested in.
247 #define BPF_F_ANY_ALIGNMENT (1U << 1)
249 /* when bpf_ldimm64->src_reg == BPF_PSEUDO_MAP_FD, bpf_ldimm64->imm == fd */
250 #define BPF_PSEUDO_MAP_FD 1
252 /* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
253 * offset to another bpf function
255 #define BPF_PSEUDO_CALL 1
257 /* flags for BPF_MAP_UPDATE_ELEM command */
258 #define BPF_ANY 0 /* create new element or update existing */
259 #define BPF_NOEXIST 1 /* create new element if it didn't exist */
260 #define BPF_EXIST 2 /* update existing element */
262 /* flags for BPF_MAP_CREATE command */
263 #define BPF_F_NO_PREALLOC (1U << 0)
264 /* Instead of having one common LRU list in the
265 * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
266 * which can scale and perform better.
267 * Note, the LRU nodes (including free nodes) cannot be moved
268 * across different LRU lists.
270 #define BPF_F_NO_COMMON_LRU (1U << 1)
271 /* Specify numa node during map creation */
272 #define BPF_F_NUMA_NODE (1U << 2)
274 #define BPF_OBJ_NAME_LEN 16U
276 /* Flags for accessing BPF object */
277 #define BPF_F_RDONLY (1U << 3)
278 #define BPF_F_WRONLY (1U << 4)
280 /* Flag for stack_map, store build_id+offset instead of pointer */
281 #define BPF_F_STACK_BUILD_ID (1U << 5)
283 /* Zero-initialize hash function seed. This should only be used for testing. */
284 #define BPF_F_ZERO_SEED (1U << 6)
286 /* flags for BPF_PROG_QUERY */
287 #define BPF_F_QUERY_EFFECTIVE (1U << 0)
289 enum bpf_stack_build_id_status {
290 /* user space need an empty entry to identify end of a trace */
291 BPF_STACK_BUILD_ID_EMPTY = 0,
292 /* with valid build_id and offset */
293 BPF_STACK_BUILD_ID_VALID = 1,
294 /* couldn't get build_id, fallback to ip */
295 BPF_STACK_BUILD_ID_IP = 2,
298 #define BPF_BUILD_ID_SIZE 20
299 struct bpf_stack_build_id {
301 unsigned char build_id[BPF_BUILD_ID_SIZE];
309 struct { /* anonymous struct used by BPF_MAP_CREATE command */
310 __u32 map_type; /* one of enum bpf_map_type */
311 __u32 key_size; /* size of key in bytes */
312 __u32 value_size; /* size of value in bytes */
313 __u32 max_entries; /* max number of entries in a map */
314 __u32 map_flags; /* BPF_MAP_CREATE related
315 * flags defined above.
317 __u32 inner_map_fd; /* fd pointing to the inner map */
318 __u32 numa_node; /* numa node (effective only if
319 * BPF_F_NUMA_NODE is set).
321 char map_name[BPF_OBJ_NAME_LEN];
322 __u32 map_ifindex; /* ifindex of netdev to create on */
323 __u32 btf_fd; /* fd pointing to a BTF type data */
324 __u32 btf_key_type_id; /* BTF type_id of the key */
325 __u32 btf_value_type_id; /* BTF type_id of the value */
328 struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
333 __aligned_u64 next_key;
338 struct { /* anonymous struct used by BPF_PROG_LOAD command */
339 __u32 prog_type; /* one of enum bpf_prog_type */
342 __aligned_u64 license;
343 __u32 log_level; /* verbosity level of verifier */
344 __u32 log_size; /* size of user buffer */
345 __aligned_u64 log_buf; /* user supplied buffer */
346 __u32 kern_version; /* checked when prog_type=kprobe */
348 char prog_name[BPF_OBJ_NAME_LEN];
349 __u32 prog_ifindex; /* ifindex of netdev to prep for */
350 /* For some prog types expected attach type must be known at
351 * load time to verify attach type specific parts of prog
352 * (context accesses, allowed helpers, etc).
354 __u32 expected_attach_type;
355 __u32 prog_btf_fd; /* fd pointing to BTF type data */
356 __u32 func_info_rec_size; /* userspace bpf_func_info size */
357 __aligned_u64 func_info; /* func info */
358 __u32 func_info_cnt; /* number of bpf_func_info records */
361 struct { /* anonymous struct used by BPF_OBJ_* commands */
362 __aligned_u64 pathname;
367 struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
368 __u32 target_fd; /* container object to attach to */
369 __u32 attach_bpf_fd; /* eBPF program to attach */
374 struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
377 __u32 data_size_in; /* input: len of data_in */
378 __u32 data_size_out; /* input/output: len of data_out
379 * returns ENOSPC if data_out
382 __aligned_u64 data_in;
383 __aligned_u64 data_out;
388 struct { /* anonymous struct used by BPF_*_GET_*_ID */
399 struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
405 struct { /* anonymous struct used by BPF_PROG_QUERY command */
406 __u32 target_fd; /* container object to query */
410 __aligned_u64 prog_ids;
419 struct { /* anonymous struct for BPF_BTF_LOAD */
421 __aligned_u64 btf_log_buf;
428 __u32 pid; /* input: pid */
429 __u32 fd; /* input: fd */
430 __u32 flags; /* input: flags */
431 __u32 buf_len; /* input/output: buf len */
432 __aligned_u64 buf; /* input/output:
433 * tp_name for tracepoint
435 * filename for uprobe
437 __u32 prog_id; /* output: prod_id */
438 __u32 fd_type; /* output: BPF_FD_TYPE_* */
439 __u64 probe_offset; /* output: probe_offset */
440 __u64 probe_addr; /* output: probe_addr */
442 } __attribute__((aligned(8)));
444 /* The description below is an attempt at providing documentation to eBPF
445 * developers about the multiple available eBPF helper functions. It can be
446 * parsed and used to produce a manual page. The workflow is the following,
447 * and requires the rst2man utility:
449 * $ ./scripts/bpf_helpers_doc.py \
450 * --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
451 * $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
452 * $ man /tmp/bpf-helpers.7
454 * Note that in order to produce this external documentation, some RST
455 * formatting is used in the descriptions to get "bold" and "italics" in
456 * manual pages. Also note that the few trailing white spaces are
457 * intentional, removing them would break paragraphs for rst2man.
459 * Start of BPF helper function descriptions:
461 * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
463 * Perform a lookup in *map* for an entry associated to *key*.
465 * Map value associated to *key*, or **NULL** if no entry was
468 * int bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
470 * Add or update the value of the entry associated to *key* in
471 * *map* with *value*. *flags* is one of:
474 * The entry for *key* must not exist in the map.
476 * The entry for *key* must already exist in the map.
478 * No condition on the existence of the entry for *key*.
480 * Flag value **BPF_NOEXIST** cannot be used for maps of types
481 * **BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY** (all
482 * elements always exist), the helper would return an error.
484 * 0 on success, or a negative error in case of failure.
486 * int bpf_map_delete_elem(struct bpf_map *map, const void *key)
488 * Delete entry with *key* from *map*.
490 * 0 on success, or a negative error in case of failure.
492 * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
494 * Push an element *value* in *map*. *flags* is one of:
497 * If the queue/stack is full, the oldest element is removed to
498 * make room for this.
500 * 0 on success, or a negative error in case of failure.
502 * int bpf_probe_read(void *dst, u32 size, const void *src)
504 * For tracing programs, safely attempt to read *size* bytes from
505 * address *src* and store the data in *dst*.
507 * 0 on success, or a negative error in case of failure.
509 * u64 bpf_ktime_get_ns(void)
511 * Return the time elapsed since system boot, in nanoseconds.
515 * int bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
517 * This helper is a "printk()-like" facility for debugging. It
518 * prints a message defined by format *fmt* (of size *fmt_size*)
519 * to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
520 * available. It can take up to three additional **u64**
521 * arguments (as an eBPF helpers, the total number of arguments is
524 * Each time the helper is called, it appends a line to the trace.
525 * The format of the trace is customizable, and the exact output
526 * one will get depends on the options set in
527 * *\/sys/kernel/debug/tracing/trace_options* (see also the
528 * *README* file under the same directory). However, it usually
529 * defaults to something like:
533 * telnet-470 [001] .N.. 419421.045894: 0x00000001: <formatted msg>
537 * * ``telnet`` is the name of the current task.
538 * * ``470`` is the PID of the current task.
539 * * ``001`` is the CPU number on which the task is
541 * * In ``.N..``, each character refers to a set of
542 * options (whether irqs are enabled, scheduling
543 * options, whether hard/softirqs are running, level of
544 * preempt_disabled respectively). **N** means that
545 * **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
547 * * ``419421.045894`` is a timestamp.
548 * * ``0x00000001`` is a fake value used by BPF for the
549 * instruction pointer register.
550 * * ``<formatted msg>`` is the message formatted with
553 * The conversion specifiers supported by *fmt* are similar, but
554 * more limited than for printk(). They are **%d**, **%i**,
555 * **%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
556 * **%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
557 * of field, padding with zeroes, etc.) is available, and the
558 * helper will return **-EINVAL** (but print nothing) if it
559 * encounters an unknown specifier.
561 * Also, note that **bpf_trace_printk**\ () is slow, and should
562 * only be used for debugging purposes. For this reason, a notice
563 * bloc (spanning several lines) is printed to kernel logs and
564 * states that the helper should not be used "for production use"
565 * the first time this helper is used (or more precisely, when
566 * **trace_printk**\ () buffers are allocated). For passing values
567 * to user space, perf events should be preferred.
569 * The number of bytes written to the buffer, or a negative error
570 * in case of failure.
572 * u32 bpf_get_prandom_u32(void)
574 * Get a pseudo-random number.
576 * From a security point of view, this helper uses its own
577 * pseudo-random internal state, and cannot be used to infer the
578 * seed of other random functions in the kernel. However, it is
579 * essential to note that the generator used by the helper is not
580 * cryptographically secure.
582 * A random 32-bit unsigned value.
584 * u32 bpf_get_smp_processor_id(void)
586 * Get the SMP (symmetric multiprocessing) processor id. Note that
587 * all programs run with preemption disabled, which means that the
588 * SMP processor id is stable during all the execution of the
591 * The SMP id of the processor running the program.
593 * int bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
595 * Store *len* bytes from address *from* into the packet
596 * associated to *skb*, at *offset*. *flags* are a combination of
597 * **BPF_F_RECOMPUTE_CSUM** (automatically recompute the
598 * checksum for the packet after storing the bytes) and
599 * **BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
600 * **->swhash** and *skb*\ **->l4hash** to 0).
602 * A call to this helper is susceptible to change the underlaying
603 * packet buffer. Therefore, at load time, all checks on pointers
604 * previously done by the verifier are invalidated and must be
605 * performed again, if the helper is used in combination with
606 * direct packet access.
608 * 0 on success, or a negative error in case of failure.
610 * int bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
612 * Recompute the layer 3 (e.g. IP) checksum for the packet
613 * associated to *skb*. Computation is incremental, so the helper
614 * must know the former value of the header field that was
615 * modified (*from*), the new value of this field (*to*), and the
616 * number of bytes (2 or 4) for this field, stored in *size*.
617 * Alternatively, it is possible to store the difference between
618 * the previous and the new values of the header field in *to*, by
619 * setting *from* and *size* to 0. For both methods, *offset*
620 * indicates the location of the IP checksum within the packet.
622 * This helper works in combination with **bpf_csum_diff**\ (),
623 * which does not update the checksum in-place, but offers more
624 * flexibility and can handle sizes larger than 2 or 4 for the
625 * checksum to update.
627 * A call to this helper is susceptible to change the underlaying
628 * packet buffer. Therefore, at load time, all checks on pointers
629 * previously done by the verifier are invalidated and must be
630 * performed again, if the helper is used in combination with
631 * direct packet access.
633 * 0 on success, or a negative error in case of failure.
635 * int bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
637 * Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
638 * packet associated to *skb*. Computation is incremental, so the
639 * helper must know the former value of the header field that was
640 * modified (*from*), the new value of this field (*to*), and the
641 * number of bytes (2 or 4) for this field, stored on the lowest
642 * four bits of *flags*. Alternatively, it is possible to store
643 * the difference between the previous and the new values of the
644 * header field in *to*, by setting *from* and the four lowest
645 * bits of *flags* to 0. For both methods, *offset* indicates the
646 * location of the IP checksum within the packet. In addition to
647 * the size of the field, *flags* can be added (bitwise OR) actual
648 * flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
649 * untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
650 * for updates resulting in a null checksum the value is set to
651 * **CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
652 * the checksum is to be computed against a pseudo-header.
654 * This helper works in combination with **bpf_csum_diff**\ (),
655 * which does not update the checksum in-place, but offers more
656 * flexibility and can handle sizes larger than 2 or 4 for the
657 * checksum to update.
659 * A call to this helper is susceptible to change the underlaying
660 * packet buffer. Therefore, at load time, all checks on pointers
661 * previously done by the verifier are invalidated and must be
662 * performed again, if the helper is used in combination with
663 * direct packet access.
665 * 0 on success, or a negative error in case of failure.
667 * int bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
669 * This special helper is used to trigger a "tail call", or in
670 * other words, to jump into another eBPF program. The same stack
671 * frame is used (but values on stack and in registers for the
672 * caller are not accessible to the callee). This mechanism allows
673 * for program chaining, either for raising the maximum number of
674 * available eBPF instructions, or to execute given programs in
675 * conditional blocks. For security reasons, there is an upper
676 * limit to the number of successive tail calls that can be
679 * Upon call of this helper, the program attempts to jump into a
680 * program referenced at index *index* in *prog_array_map*, a
681 * special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
682 * *ctx*, a pointer to the context.
684 * If the call succeeds, the kernel immediately runs the first
685 * instruction of the new program. This is not a function call,
686 * and it never returns to the previous program. If the call
687 * fails, then the helper has no effect, and the caller continues
688 * to run its subsequent instructions. A call can fail if the
689 * destination program for the jump does not exist (i.e. *index*
690 * is superior to the number of entries in *prog_array_map*), or
691 * if the maximum number of tail calls has been reached for this
692 * chain of programs. This limit is defined in the kernel by the
693 * macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
694 * which is currently set to 32.
696 * 0 on success, or a negative error in case of failure.
698 * int bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
700 * Clone and redirect the packet associated to *skb* to another
701 * net device of index *ifindex*. Both ingress and egress
702 * interfaces can be used for redirection. The **BPF_F_INGRESS**
703 * value in *flags* is used to make the distinction (ingress path
704 * is selected if the flag is present, egress path otherwise).
705 * This is the only flag supported for now.
707 * In comparison with **bpf_redirect**\ () helper,
708 * **bpf_clone_redirect**\ () has the associated cost of
709 * duplicating the packet buffer, but this can be executed out of
710 * the eBPF program. Conversely, **bpf_redirect**\ () is more
711 * efficient, but it is handled through an action code where the
712 * redirection happens only after the eBPF program has returned.
714 * A call to this helper is susceptible to change the underlaying
715 * packet buffer. Therefore, at load time, all checks on pointers
716 * previously done by the verifier are invalidated and must be
717 * performed again, if the helper is used in combination with
718 * direct packet access.
720 * 0 on success, or a negative error in case of failure.
722 * u64 bpf_get_current_pid_tgid(void)
724 * A 64-bit integer containing the current tgid and pid, and
726 * *current_task*\ **->tgid << 32 \|**
727 * *current_task*\ **->pid**.
729 * u64 bpf_get_current_uid_gid(void)
731 * A 64-bit integer containing the current GID and UID, and
732 * created as such: *current_gid* **<< 32 \|** *current_uid*.
734 * int bpf_get_current_comm(char *buf, u32 size_of_buf)
736 * Copy the **comm** attribute of the current task into *buf* of
737 * *size_of_buf*. The **comm** attribute contains the name of
738 * the executable (excluding the path) for the current task. The
739 * *size_of_buf* must be strictly positive. On success, the
740 * helper makes sure that the *buf* is NUL-terminated. On failure,
741 * it is filled with zeroes.
743 * 0 on success, or a negative error in case of failure.
745 * u32 bpf_get_cgroup_classid(struct sk_buff *skb)
747 * Retrieve the classid for the current task, i.e. for the net_cls
748 * cgroup to which *skb* belongs.
750 * This helper can be used on TC egress path, but not on ingress.
752 * The net_cls cgroup provides an interface to tag network packets
753 * based on a user-provided identifier for all traffic coming from
754 * the tasks belonging to the related cgroup. See also the related
755 * kernel documentation, available from the Linux sources in file
756 * *Documentation/cgroup-v1/net_cls.txt*.
758 * The Linux kernel has two versions for cgroups: there are
759 * cgroups v1 and cgroups v2. Both are available to users, who can
760 * use a mixture of them, but note that the net_cls cgroup is for
761 * cgroup v1 only. This makes it incompatible with BPF programs
762 * run on cgroups, which is a cgroup-v2-only feature (a socket can
763 * only hold data for one version of cgroups at a time).
765 * This helper is only available is the kernel was compiled with
766 * the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
767 * "**y**" or to "**m**".
769 * The classid, or 0 for the default unconfigured classid.
771 * int bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
773 * Push a *vlan_tci* (VLAN tag control information) of protocol
774 * *vlan_proto* to the packet associated to *skb*, then update
775 * the checksum. Note that if *vlan_proto* is different from
776 * **ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
777 * be **ETH_P_8021Q**.
779 * A call to this helper is susceptible to change the underlaying
780 * packet buffer. Therefore, at load time, all checks on pointers
781 * previously done by the verifier are invalidated and must be
782 * performed again, if the helper is used in combination with
783 * direct packet access.
785 * 0 on success, or a negative error in case of failure.
787 * int bpf_skb_vlan_pop(struct sk_buff *skb)
789 * Pop a VLAN header from the packet associated to *skb*.
791 * A call to this helper is susceptible to change the underlaying
792 * packet buffer. Therefore, at load time, all checks on pointers
793 * previously done by the verifier are invalidated and must be
794 * performed again, if the helper is used in combination with
795 * direct packet access.
797 * 0 on success, or a negative error in case of failure.
799 * int bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
801 * Get tunnel metadata. This helper takes a pointer *key* to an
802 * empty **struct bpf_tunnel_key** of **size**, that will be
803 * filled with tunnel metadata for the packet associated to *skb*.
804 * The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
805 * indicates that the tunnel is based on IPv6 protocol instead of
808 * The **struct bpf_tunnel_key** is an object that generalizes the
809 * principal parameters used by various tunneling protocols into a
810 * single struct. This way, it can be used to easily make a
811 * decision based on the contents of the encapsulation header,
812 * "summarized" in this struct. In particular, it holds the IP
813 * address of the remote end (IPv4 or IPv6, depending on the case)
814 * in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
815 * this struct exposes the *key*\ **->tunnel_id**, which is
816 * generally mapped to a VNI (Virtual Network Identifier), making
817 * it programmable together with the **bpf_skb_set_tunnel_key**\
820 * Let's imagine that the following code is part of a program
821 * attached to the TC ingress interface, on one end of a GRE
822 * tunnel, and is supposed to filter out all messages coming from
823 * remote ends with IPv4 address other than 10.0.0.1:
828 * struct bpf_tunnel_key key = {};
830 * ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
832 * return TC_ACT_SHOT; // drop packet
834 * if (key.remote_ipv4 != 0x0a000001)
835 * return TC_ACT_SHOT; // drop packet
837 * return TC_ACT_OK; // accept packet
839 * This interface can also be used with all encapsulation devices
840 * that can operate in "collect metadata" mode: instead of having
841 * one network device per specific configuration, the "collect
842 * metadata" mode only requires a single device where the
843 * configuration can be extracted from this helper.
845 * This can be used together with various tunnels such as VXLan,
846 * Geneve, GRE or IP in IP (IPIP).
848 * 0 on success, or a negative error in case of failure.
850 * int bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
852 * Populate tunnel metadata for packet associated to *skb.* The
853 * tunnel metadata is set to the contents of *key*, of *size*. The
854 * *flags* can be set to a combination of the following values:
856 * **BPF_F_TUNINFO_IPV6**
857 * Indicate that the tunnel is based on IPv6 protocol
859 * **BPF_F_ZERO_CSUM_TX**
860 * For IPv4 packets, add a flag to tunnel metadata
861 * indicating that checksum computation should be skipped
862 * and checksum set to zeroes.
863 * **BPF_F_DONT_FRAGMENT**
864 * Add a flag to tunnel metadata indicating that the
865 * packet should not be fragmented.
866 * **BPF_F_SEQ_NUMBER**
867 * Add a flag to tunnel metadata indicating that a
868 * sequence number should be added to tunnel header before
869 * sending the packet. This flag was added for GRE
870 * encapsulation, but might be used with other protocols
871 * as well in the future.
873 * Here is a typical usage on the transmit path:
877 * struct bpf_tunnel_key key;
879 * bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
880 * bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
882 * See also the description of the **bpf_skb_get_tunnel_key**\ ()
883 * helper for additional information.
885 * 0 on success, or a negative error in case of failure.
887 * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
889 * Read the value of a perf event counter. This helper relies on a
890 * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
891 * the perf event counter is selected when *map* is updated with
892 * perf event file descriptors. The *map* is an array whose size
893 * is the number of available CPUs, and each cell contains a value
894 * relative to one CPU. The value to retrieve is indicated by
895 * *flags*, that contains the index of the CPU to look up, masked
896 * with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
897 * **BPF_F_CURRENT_CPU** to indicate that the value for the
898 * current CPU should be retrieved.
900 * Note that before Linux 4.13, only hardware perf event can be
903 * Also, be aware that the newer helper
904 * **bpf_perf_event_read_value**\ () is recommended over
905 * **bpf_perf_event_read**\ () in general. The latter has some ABI
906 * quirks where error and counter value are used as a return code
907 * (which is wrong to do since ranges may overlap). This issue is
908 * fixed with **bpf_perf_event_read_value**\ (), which at the same
909 * time provides more features over the **bpf_perf_event_read**\
910 * () interface. Please refer to the description of
911 * **bpf_perf_event_read_value**\ () for details.
913 * The value of the perf event counter read from the map, or a
914 * negative error code in case of failure.
916 * int bpf_redirect(u32 ifindex, u64 flags)
918 * Redirect the packet to another net device of index *ifindex*.
919 * This helper is somewhat similar to **bpf_clone_redirect**\
920 * (), except that the packet is not cloned, which provides
921 * increased performance.
923 * Except for XDP, both ingress and egress interfaces can be used
924 * for redirection. The **BPF_F_INGRESS** value in *flags* is used
925 * to make the distinction (ingress path is selected if the flag
926 * is present, egress path otherwise). Currently, XDP only
927 * supports redirection to the egress interface, and accepts no
930 * The same effect can be attained with the more generic
931 * **bpf_redirect_map**\ (), which requires specific maps to be
932 * used but offers better performance.
934 * For XDP, the helper returns **XDP_REDIRECT** on success or
935 * **XDP_ABORTED** on error. For other program types, the values
936 * are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
939 * u32 bpf_get_route_realm(struct sk_buff *skb)
941 * Retrieve the realm or the route, that is to say the
942 * **tclassid** field of the destination for the *skb*. The
943 * indentifier retrieved is a user-provided tag, similar to the
944 * one used with the net_cls cgroup (see description for
945 * **bpf_get_cgroup_classid**\ () helper), but here this tag is
946 * held by a route (a destination entry), not by a task.
948 * Retrieving this identifier works with the clsact TC egress hook
949 * (see also **tc-bpf(8)**), or alternatively on conventional
950 * classful egress qdiscs, but not on TC ingress path. In case of
951 * clsact TC egress hook, this has the advantage that, internally,
952 * the destination entry has not been dropped yet in the transmit
953 * path. Therefore, the destination entry does not need to be
954 * artificially held via **netif_keep_dst**\ () for a classful
955 * qdisc until the *skb* is freed.
957 * This helper is available only if the kernel was compiled with
958 * **CONFIG_IP_ROUTE_CLASSID** configuration option.
960 * The realm of the route for the packet associated to *skb*, or 0
963 * int bpf_perf_event_output(struct pt_reg *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
965 * Write raw *data* blob into a special BPF perf event held by
966 * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
967 * event must have the following attributes: **PERF_SAMPLE_RAW**
968 * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
969 * **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
971 * The *flags* are used to indicate the index in *map* for which
972 * the value must be put, masked with **BPF_F_INDEX_MASK**.
973 * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
974 * to indicate that the index of the current CPU core should be
977 * The value to write, of *size*, is passed through eBPF stack and
980 * The context of the program *ctx* needs also be passed to the
983 * On user space, a program willing to read the values needs to
984 * call **perf_event_open**\ () on the perf event (either for
985 * one or for all CPUs) and to store the file descriptor into the
986 * *map*. This must be done before the eBPF program can send data
987 * into it. An example is available in file
988 * *samples/bpf/trace_output_user.c* in the Linux kernel source
989 * tree (the eBPF program counterpart is in
990 * *samples/bpf/trace_output_kern.c*).
992 * **bpf_perf_event_output**\ () achieves better performance
993 * than **bpf_trace_printk**\ () for sharing data with user
994 * space, and is much better suitable for streaming data from eBPF
997 * Note that this helper is not restricted to tracing use cases
998 * and can be used with programs attached to TC or XDP as well,
999 * where it allows for passing data to user space listeners. Data
1002 * * Only custom structs,
1003 * * Only the packet payload, or
1004 * * A combination of both.
1006 * 0 on success, or a negative error in case of failure.
1008 * int bpf_skb_load_bytes(const struct sk_buff *skb, u32 offset, void *to, u32 len)
1010 * This helper was provided as an easy way to load data from a
1011 * packet. It can be used to load *len* bytes from *offset* from
1012 * the packet associated to *skb*, into the buffer pointed by
1015 * Since Linux 4.7, usage of this helper has mostly been replaced
1016 * by "direct packet access", enabling packet data to be
1017 * manipulated with *skb*\ **->data** and *skb*\ **->data_end**
1018 * pointing respectively to the first byte of packet data and to
1019 * the byte after the last byte of packet data. However, it
1020 * remains useful if one wishes to read large quantities of data
1021 * at once from a packet into the eBPF stack.
1023 * 0 on success, or a negative error in case of failure.
1025 * int bpf_get_stackid(struct pt_reg *ctx, struct bpf_map *map, u64 flags)
1027 * Walk a user or a kernel stack and return its id. To achieve
1028 * this, the helper needs *ctx*, which is a pointer to the context
1029 * on which the tracing program is executed, and a pointer to a
1030 * *map* of type **BPF_MAP_TYPE_STACK_TRACE**.
1032 * The last argument, *flags*, holds the number of stack frames to
1033 * skip (from 0 to 255), masked with
1034 * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
1035 * a combination of the following flags:
1037 * **BPF_F_USER_STACK**
1038 * Collect a user space stack instead of a kernel stack.
1039 * **BPF_F_FAST_STACK_CMP**
1040 * Compare stacks by hash only.
1041 * **BPF_F_REUSE_STACKID**
1042 * If two different stacks hash into the same *stackid*,
1043 * discard the old one.
1045 * The stack id retrieved is a 32 bit long integer handle which
1046 * can be further combined with other data (including other stack
1047 * ids) and used as a key into maps. This can be useful for
1048 * generating a variety of graphs (such as flame graphs or off-cpu
1051 * For walking a stack, this helper is an improvement over
1052 * **bpf_probe_read**\ (), which can be used with unrolled loops
1053 * but is not efficient and consumes a lot of eBPF instructions.
1054 * Instead, **bpf_get_stackid**\ () can collect up to
1055 * **PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
1056 * this limit can be controlled with the **sysctl** program, and
1057 * that it should be manually increased in order to profile long
1058 * user stacks (such as stacks for Java programs). To do so, use:
1062 * # sysctl kernel.perf_event_max_stack=<new value>
1064 * The positive or null stack id on success, or a negative error
1065 * in case of failure.
1067 * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
1069 * Compute a checksum difference, from the raw buffer pointed by
1070 * *from*, of length *from_size* (that must be a multiple of 4),
1071 * towards the raw buffer pointed by *to*, of size *to_size*
1072 * (same remark). An optional *seed* can be added to the value
1073 * (this can be cascaded, the seed may come from a previous call
1076 * This is flexible enough to be used in several ways:
1078 * * With *from_size* == 0, *to_size* > 0 and *seed* set to
1079 * checksum, it can be used when pushing new data.
1080 * * With *from_size* > 0, *to_size* == 0 and *seed* set to
1081 * checksum, it can be used when removing data from a packet.
1082 * * With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
1083 * can be used to compute a diff. Note that *from_size* and
1084 * *to_size* do not need to be equal.
1086 * This helper can be used in combination with
1087 * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
1088 * which one can feed in the difference computed with
1089 * **bpf_csum_diff**\ ().
1091 * The checksum result, or a negative error code in case of
1094 * int bpf_skb_get_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
1096 * Retrieve tunnel options metadata for the packet associated to
1097 * *skb*, and store the raw tunnel option data to the buffer *opt*
1100 * This helper can be used with encapsulation devices that can
1101 * operate in "collect metadata" mode (please refer to the related
1102 * note in the description of **bpf_skb_get_tunnel_key**\ () for
1103 * more details). A particular example where this can be used is
1104 * in combination with the Geneve encapsulation protocol, where it
1105 * allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
1106 * and retrieving arbitrary TLVs (Type-Length-Value headers) from
1107 * the eBPF program. This allows for full customization of these
1110 * The size of the option data retrieved.
1112 * int bpf_skb_set_tunnel_opt(struct sk_buff *skb, u8 *opt, u32 size)
1114 * Set tunnel options metadata for the packet associated to *skb*
1115 * to the option data contained in the raw buffer *opt* of *size*.
1117 * See also the description of the **bpf_skb_get_tunnel_opt**\ ()
1118 * helper for additional information.
1120 * 0 on success, or a negative error in case of failure.
1122 * int bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
1124 * Change the protocol of the *skb* to *proto*. Currently
1125 * supported are transition from IPv4 to IPv6, and from IPv6 to
1126 * IPv4. The helper takes care of the groundwork for the
1127 * transition, including resizing the socket buffer. The eBPF
1128 * program is expected to fill the new headers, if any, via
1129 * **skb_store_bytes**\ () and to recompute the checksums with
1130 * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
1131 * (). The main case for this helper is to perform NAT64
1132 * operations out of an eBPF program.
1134 * Internally, the GSO type is marked as dodgy so that headers are
1135 * checked and segments are recalculated by the GSO/GRO engine.
1136 * The size for GSO target is adapted as well.
1138 * All values for *flags* are reserved for future usage, and must
1141 * A call to this helper is susceptible to change the underlaying
1142 * packet buffer. Therefore, at load time, all checks on pointers
1143 * previously done by the verifier are invalidated and must be
1144 * performed again, if the helper is used in combination with
1145 * direct packet access.
1147 * 0 on success, or a negative error in case of failure.
1149 * int bpf_skb_change_type(struct sk_buff *skb, u32 type)
1151 * Change the packet type for the packet associated to *skb*. This
1152 * comes down to setting *skb*\ **->pkt_type** to *type*, except
1153 * the eBPF program does not have a write access to *skb*\
1154 * **->pkt_type** beside this helper. Using a helper here allows
1155 * for graceful handling of errors.
1157 * The major use case is to change incoming *skb*s to
1158 * **PACKET_HOST** in a programmatic way instead of having to
1159 * recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
1162 * Note that *type* only allows certain values. At this time, they
1167 * **PACKET_BROADCAST**
1168 * Send packet to all.
1169 * **PACKET_MULTICAST**
1170 * Send packet to group.
1171 * **PACKET_OTHERHOST**
1172 * Send packet to someone else.
1174 * 0 on success, or a negative error in case of failure.
1176 * int bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
1178 * Check whether *skb* is a descendant of the cgroup2 held by
1179 * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
1181 * The return value depends on the result of the test, and can be:
1183 * * 0, if the *skb* failed the cgroup2 descendant test.
1184 * * 1, if the *skb* succeeded the cgroup2 descendant test.
1185 * * A negative error code, if an error occurred.
1187 * u32 bpf_get_hash_recalc(struct sk_buff *skb)
1189 * Retrieve the hash of the packet, *skb*\ **->hash**. If it is
1190 * not set, in particular if the hash was cleared due to mangling,
1191 * recompute this hash. Later accesses to the hash can be done
1192 * directly with *skb*\ **->hash**.
1194 * Calling **bpf_set_hash_invalid**\ (), changing a packet
1195 * prototype with **bpf_skb_change_proto**\ (), or calling
1196 * **bpf_skb_store_bytes**\ () with the
1197 * **BPF_F_INVALIDATE_HASH** are actions susceptible to clear
1198 * the hash and to trigger a new computation for the next call to
1199 * **bpf_get_hash_recalc**\ ().
1203 * u64 bpf_get_current_task(void)
1205 * A pointer to the current task struct.
1207 * int bpf_probe_write_user(void *dst, const void *src, u32 len)
1209 * Attempt in a safe way to write *len* bytes from the buffer
1210 * *src* to *dst* in memory. It only works for threads that are in
1211 * user context, and *dst* must be a valid user space address.
1213 * This helper should not be used to implement any kind of
1214 * security mechanism because of TOC-TOU attacks, but rather to
1215 * debug, divert, and manipulate execution of semi-cooperative
1218 * Keep in mind that this feature is meant for experiments, and it
1219 * has a risk of crashing the system and running programs.
1220 * Therefore, when an eBPF program using this helper is attached,
1221 * a warning including PID and process name is printed to kernel
1224 * 0 on success, or a negative error in case of failure.
1226 * int bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
1228 * Check whether the probe is being run is the context of a given
1229 * subset of the cgroup2 hierarchy. The cgroup2 to test is held by
1230 * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
1232 * The return value depends on the result of the test, and can be:
1234 * * 0, if the *skb* task belongs to the cgroup2.
1235 * * 1, if the *skb* task does not belong to the cgroup2.
1236 * * A negative error code, if an error occurred.
1238 * int bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
1240 * Resize (trim or grow) the packet associated to *skb* to the
1241 * new *len*. The *flags* are reserved for future usage, and must
1244 * The basic idea is that the helper performs the needed work to
1245 * change the size of the packet, then the eBPF program rewrites
1246 * the rest via helpers like **bpf_skb_store_bytes**\ (),
1247 * **bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
1248 * and others. This helper is a slow path utility intended for
1249 * replies with control messages. And because it is targeted for
1250 * slow path, the helper itself can afford to be slow: it
1251 * implicitly linearizes, unclones and drops offloads from the
1254 * A call to this helper is susceptible to change the underlaying
1255 * packet buffer. Therefore, at load time, all checks on pointers
1256 * previously done by the verifier are invalidated and must be
1257 * performed again, if the helper is used in combination with
1258 * direct packet access.
1260 * 0 on success, or a negative error in case of failure.
1262 * int bpf_skb_pull_data(struct sk_buff *skb, u32 len)
1264 * Pull in non-linear data in case the *skb* is non-linear and not
1265 * all of *len* are part of the linear section. Make *len* bytes
1266 * from *skb* readable and writable. If a zero value is passed for
1267 * *len*, then the whole length of the *skb* is pulled.
1269 * This helper is only needed for reading and writing with direct
1272 * For direct packet access, testing that offsets to access
1273 * are within packet boundaries (test on *skb*\ **->data_end**) is
1274 * susceptible to fail if offsets are invalid, or if the requested
1275 * data is in non-linear parts of the *skb*. On failure the
1276 * program can just bail out, or in the case of a non-linear
1277 * buffer, use a helper to make the data available. The
1278 * **bpf_skb_load_bytes**\ () helper is a first solution to access
1279 * the data. Another one consists in using **bpf_skb_pull_data**
1280 * to pull in once the non-linear parts, then retesting and
1281 * eventually access the data.
1283 * At the same time, this also makes sure the *skb* is uncloned,
1284 * which is a necessary condition for direct write. As this needs
1285 * to be an invariant for the write part only, the verifier
1286 * detects writes and adds a prologue that is calling
1287 * **bpf_skb_pull_data()** to effectively unclone the *skb* from
1288 * the very beginning in case it is indeed cloned.
1290 * A call to this helper is susceptible to change the underlaying
1291 * packet buffer. Therefore, at load time, all checks on pointers
1292 * previously done by the verifier are invalidated and must be
1293 * performed again, if the helper is used in combination with
1294 * direct packet access.
1296 * 0 on success, or a negative error in case of failure.
1298 * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
1300 * Add the checksum *csum* into *skb*\ **->csum** in case the
1301 * driver has supplied a checksum for the entire packet into that
1302 * field. Return an error otherwise. This helper is intended to be
1303 * used in combination with **bpf_csum_diff**\ (), in particular
1304 * when the checksum needs to be updated after data has been
1305 * written into the packet through direct packet access.
1307 * The checksum on success, or a negative error code in case of
1310 * void bpf_set_hash_invalid(struct sk_buff *skb)
1312 * Invalidate the current *skb*\ **->hash**. It can be used after
1313 * mangling on headers through direct packet access, in order to
1314 * indicate that the hash is outdated and to trigger a
1315 * recalculation the next time the kernel tries to access this
1316 * hash or when the **bpf_get_hash_recalc**\ () helper is called.
1318 * int bpf_get_numa_node_id(void)
1320 * Return the id of the current NUMA node. The primary use case
1321 * for this helper is the selection of sockets for the local NUMA
1322 * node, when the program is attached to sockets using the
1323 * **SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
1324 * but the helper is also available to other eBPF program types,
1325 * similarly to **bpf_get_smp_processor_id**\ ().
1327 * The id of current NUMA node.
1329 * int bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
1331 * Grows headroom of packet associated to *skb* and adjusts the
1332 * offset of the MAC header accordingly, adding *len* bytes of
1333 * space. It automatically extends and reallocates memory as
1336 * This helper can be used on a layer 3 *skb* to push a MAC header
1337 * for redirection into a layer 2 device.
1339 * All values for *flags* are reserved for future usage, and must
1342 * A call to this helper is susceptible to change the underlaying
1343 * packet buffer. Therefore, at load time, all checks on pointers
1344 * previously done by the verifier are invalidated and must be
1345 * performed again, if the helper is used in combination with
1346 * direct packet access.
1348 * 0 on success, or a negative error in case of failure.
1350 * int bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
1352 * Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
1353 * it is possible to use a negative value for *delta*. This helper
1354 * can be used to prepare the packet for pushing or popping
1357 * A call to this helper is susceptible to change the underlaying
1358 * packet buffer. Therefore, at load time, all checks on pointers
1359 * previously done by the verifier are invalidated and must be
1360 * performed again, if the helper is used in combination with
1361 * direct packet access.
1363 * 0 on success, or a negative error in case of failure.
1365 * int bpf_probe_read_str(void *dst, int size, const void *unsafe_ptr)
1367 * Copy a NUL terminated string from an unsafe address
1368 * *unsafe_ptr* to *dst*. The *size* should include the
1369 * terminating NUL byte. In case the string length is smaller than
1370 * *size*, the target is not padded with further NUL bytes. If the
1371 * string length is larger than *size*, just *size*-1 bytes are
1372 * copied and the last byte is set to NUL.
1374 * On success, the length of the copied string is returned. This
1375 * makes this helper useful in tracing programs for reading
1376 * strings, and more importantly to get its length at runtime. See
1377 * the following snippet:
1381 * SEC("kprobe/sys_open")
1382 * void bpf_sys_open(struct pt_regs *ctx)
1384 * char buf[PATHLEN]; // PATHLEN is defined to 256
1385 * int res = bpf_probe_read_str(buf, sizeof(buf),
1388 * // Consume buf, for example push it to
1389 * // userspace via bpf_perf_event_output(); we
1390 * // can use res (the string length) as event
1391 * // size, after checking its boundaries.
1394 * In comparison, using **bpf_probe_read()** helper here instead
1395 * to read the string would require to estimate the length at
1396 * compile time, and would often result in copying more memory
1399 * Another useful use case is when parsing individual process
1400 * arguments or individual environment variables navigating
1401 * *current*\ **->mm->arg_start** and *current*\
1402 * **->mm->env_start**: using this helper and the return value,
1403 * one can quickly iterate at the right offset of the memory area.
1405 * On success, the strictly positive length of the string,
1406 * including the trailing NUL character. On error, a negative
1409 * u64 bpf_get_socket_cookie(struct sk_buff *skb)
1411 * If the **struct sk_buff** pointed by *skb* has a known socket,
1412 * retrieve the cookie (generated by the kernel) of this socket.
1413 * If no cookie has been set yet, generate a new cookie. Once
1414 * generated, the socket cookie remains stable for the life of the
1415 * socket. This helper can be useful for monitoring per socket
1416 * networking traffic statistics as it provides a unique socket
1417 * identifier per namespace.
1419 * A 8-byte long non-decreasing number on success, or 0 if the
1420 * socket field is missing inside *skb*.
1422 * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
1424 * Equivalent to bpf_get_socket_cookie() helper that accepts
1425 * *skb*, but gets socket from **struct bpf_sock_addr** contex.
1427 * A 8-byte long non-decreasing number.
1429 * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
1431 * Equivalent to bpf_get_socket_cookie() helper that accepts
1432 * *skb*, but gets socket from **struct bpf_sock_ops** contex.
1434 * A 8-byte long non-decreasing number.
1436 * u32 bpf_get_socket_uid(struct sk_buff *skb)
1438 * The owner UID of the socket associated to *skb*. If the socket
1439 * is **NULL**, or if it is not a full socket (i.e. if it is a
1440 * time-wait or a request socket instead), **overflowuid** value
1441 * is returned (note that **overflowuid** might also be the actual
1442 * UID value for the socket).
1444 * u32 bpf_set_hash(struct sk_buff *skb, u32 hash)
1446 * Set the full hash for *skb* (set the field *skb*\ **->hash**)
1451 * int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
1453 * Emulate a call to **setsockopt()** on the socket associated to
1454 * *bpf_socket*, which must be a full socket. The *level* at
1455 * which the option resides and the name *optname* of the option
1456 * must be specified, see **setsockopt(2)** for more information.
1457 * The option value of length *optlen* is pointed by *optval*.
1459 * This helper actually implements a subset of **setsockopt()**.
1460 * It supports the following *level*\ s:
1462 * * **SOL_SOCKET**, which supports the following *optname*\ s:
1463 * **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
1464 * **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**.
1465 * * **IPPROTO_TCP**, which supports the following *optname*\ s:
1466 * **TCP_CONGESTION**, **TCP_BPF_IW**,
1467 * **TCP_BPF_SNDCWND_CLAMP**.
1468 * * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
1469 * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
1471 * 0 on success, or a negative error in case of failure.
1473 * int bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
1475 * Grow or shrink the room for data in the packet associated to
1476 * *skb* by *len_diff*, and according to the selected *mode*.
1478 * There is a single supported mode at this time:
1480 * * **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
1481 * (room space is added or removed below the layer 3 header).
1483 * All values for *flags* are reserved for future usage, and must
1486 * A call to this helper is susceptible to change the underlaying
1487 * packet buffer. Therefore, at load time, all checks on pointers
1488 * previously done by the verifier are invalidated and must be
1489 * performed again, if the helper is used in combination with
1490 * direct packet access.
1492 * 0 on success, or a negative error in case of failure.
1494 * int bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
1496 * Redirect the packet to the endpoint referenced by *map* at
1497 * index *key*. Depending on its type, this *map* can contain
1498 * references to net devices (for forwarding packets through other
1499 * ports), or to CPUs (for redirecting XDP frames to another CPU;
1500 * but this is only implemented for native XDP (with driver
1501 * support) as of this writing).
1503 * All values for *flags* are reserved for future usage, and must
1506 * When used to redirect packets to net devices, this helper
1507 * provides a high performance increase over **bpf_redirect**\ ().
1508 * This is due to various implementation details of the underlying
1509 * mechanisms, one of which is the fact that **bpf_redirect_map**\
1510 * () tries to send packet as a "bulk" to the device.
1512 * **XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
1514 * int bpf_sk_redirect_map(struct bpf_map *map, u32 key, u64 flags)
1516 * Redirect the packet to the socket referenced by *map* (of type
1517 * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
1518 * egress interfaces can be used for redirection. The
1519 * **BPF_F_INGRESS** value in *flags* is used to make the
1520 * distinction (ingress path is selected if the flag is present,
1521 * egress path otherwise). This is the only flag supported for now.
1523 * **SK_PASS** on success, or **SK_DROP** on error.
1525 * int bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
1527 * Add an entry to, or update a *map* referencing sockets. The
1528 * *skops* is used as a new value for the entry associated to
1529 * *key*. *flags* is one of:
1532 * The entry for *key* must not exist in the map.
1534 * The entry for *key* must already exist in the map.
1536 * No condition on the existence of the entry for *key*.
1538 * If the *map* has eBPF programs (parser and verdict), those will
1539 * be inherited by the socket being added. If the socket is
1540 * already attached to eBPF programs, this results in an error.
1542 * 0 on success, or a negative error in case of failure.
1544 * int bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
1546 * Adjust the address pointed by *xdp_md*\ **->data_meta** by
1547 * *delta* (which can be positive or negative). Note that this
1548 * operation modifies the address stored in *xdp_md*\ **->data**,
1549 * so the latter must be loaded only after the helper has been
1552 * The use of *xdp_md*\ **->data_meta** is optional and programs
1553 * are not required to use it. The rationale is that when the
1554 * packet is processed with XDP (e.g. as DoS filter), it is
1555 * possible to push further meta data along with it before passing
1556 * to the stack, and to give the guarantee that an ingress eBPF
1557 * program attached as a TC classifier on the same device can pick
1558 * this up for further post-processing. Since TC works with socket
1559 * buffers, it remains possible to set from XDP the **mark** or
1560 * **priority** pointers, or other pointers for the socket buffer.
1561 * Having this scratch space generic and programmable allows for
1562 * more flexibility as the user is free to store whatever meta
1565 * A call to this helper is susceptible to change the underlaying
1566 * packet buffer. Therefore, at load time, all checks on pointers
1567 * previously done by the verifier are invalidated and must be
1568 * performed again, if the helper is used in combination with
1569 * direct packet access.
1571 * 0 on success, or a negative error in case of failure.
1573 * int bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
1575 * Read the value of a perf event counter, and store it into *buf*
1576 * of size *buf_size*. This helper relies on a *map* of type
1577 * **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
1578 * counter is selected when *map* is updated with perf event file
1579 * descriptors. The *map* is an array whose size is the number of
1580 * available CPUs, and each cell contains a value relative to one
1581 * CPU. The value to retrieve is indicated by *flags*, that
1582 * contains the index of the CPU to look up, masked with
1583 * **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
1584 * **BPF_F_CURRENT_CPU** to indicate that the value for the
1585 * current CPU should be retrieved.
1587 * This helper behaves in a way close to
1588 * **bpf_perf_event_read**\ () helper, save that instead of
1589 * just returning the value observed, it fills the *buf*
1590 * structure. This allows for additional data to be retrieved: in
1591 * particular, the enabled and running times (in *buf*\
1592 * **->enabled** and *buf*\ **->running**, respectively) are
1593 * copied. In general, **bpf_perf_event_read_value**\ () is
1594 * recommended over **bpf_perf_event_read**\ (), which has some
1595 * ABI issues and provides fewer functionalities.
1597 * These values are interesting, because hardware PMU (Performance
1598 * Monitoring Unit) counters are limited resources. When there are
1599 * more PMU based perf events opened than available counters,
1600 * kernel will multiplex these events so each event gets certain
1601 * percentage (but not all) of the PMU time. In case that
1602 * multiplexing happens, the number of samples or counter value
1603 * will not reflect the case compared to when no multiplexing
1604 * occurs. This makes comparison between different runs difficult.
1605 * Typically, the counter value should be normalized before
1606 * comparing to other experiments. The usual normalization is done
1611 * normalized_counter = counter * t_enabled / t_running
1613 * Where t_enabled is the time enabled for event and t_running is
1614 * the time running for event since last normalization. The
1615 * enabled and running times are accumulated since the perf event
1616 * open. To achieve scaling factor between two invocations of an
1617 * eBPF program, users can can use CPU id as the key (which is
1618 * typical for perf array usage model) to remember the previous
1619 * value and do the calculation inside the eBPF program.
1621 * 0 on success, or a negative error in case of failure.
1623 * int bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
1625 * For en eBPF program attached to a perf event, retrieve the
1626 * value of the event counter associated to *ctx* and store it in
1627 * the structure pointed by *buf* and of size *buf_size*. Enabled
1628 * and running times are also stored in the structure (see
1629 * description of helper **bpf_perf_event_read_value**\ () for
1632 * 0 on success, or a negative error in case of failure.
1634 * int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, char *optval, int optlen)
1636 * Emulate a call to **getsockopt()** on the socket associated to
1637 * *bpf_socket*, which must be a full socket. The *level* at
1638 * which the option resides and the name *optname* of the option
1639 * must be specified, see **getsockopt(2)** for more information.
1640 * The retrieved value is stored in the structure pointed by
1641 * *opval* and of length *optlen*.
1643 * This helper actually implements a subset of **getsockopt()**.
1644 * It supports the following *level*\ s:
1646 * * **IPPROTO_TCP**, which supports *optname*
1647 * **TCP_CONGESTION**.
1648 * * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
1649 * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
1651 * 0 on success, or a negative error in case of failure.
1653 * int bpf_override_return(struct pt_reg *regs, u64 rc)
1655 * Used for error injection, this helper uses kprobes to override
1656 * the return value of the probed function, and to set it to *rc*.
1657 * The first argument is the context *regs* on which the kprobe
1660 * This helper works by setting setting the PC (program counter)
1661 * to an override function which is run in place of the original
1662 * probed function. This means the probed function is not run at
1663 * all. The replacement function just returns with the required
1666 * This helper has security implications, and thus is subject to
1667 * restrictions. It is only available if the kernel was compiled
1668 * with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
1669 * option, and in this case it only works on functions tagged with
1670 * **ALLOW_ERROR_INJECTION** in the kernel code.
1672 * Also, the helper is only available for the architectures having
1673 * the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
1674 * x86 architecture is the only one to support this feature.
1678 * int bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
1680 * Attempt to set the value of the **bpf_sock_ops_cb_flags** field
1681 * for the full TCP socket associated to *bpf_sock_ops* to
1684 * The primary use of this field is to determine if there should
1685 * be calls to eBPF programs of type
1686 * **BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
1687 * code. A program of the same type can change its value, per
1688 * connection and as necessary, when the connection is
1689 * established. This field is directly accessible for reading, but
1690 * this helper must be used for updates in order to return an
1691 * error if an eBPF program tries to set a callback that is not
1692 * supported in the current kernel.
1694 * The supported callback values that *argval* can combine are:
1696 * * **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
1697 * * **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
1698 * * **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
1700 * Here are some examples of where one could call such eBPF
1704 * * When a packet is retransmitted.
1705 * * When the connection terminates.
1706 * * When a packet is sent.
1707 * * When a packet is received.
1709 * Code **-EINVAL** if the socket is not a full TCP socket;
1710 * otherwise, a positive number containing the bits that could not
1711 * be set is returned (which comes down to 0 if all bits were set
1714 * int bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
1716 * This helper is used in programs implementing policies at the
1717 * socket level. If the message *msg* is allowed to pass (i.e. if
1718 * the verdict eBPF program returns **SK_PASS**), redirect it to
1719 * the socket referenced by *map* (of type
1720 * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
1721 * egress interfaces can be used for redirection. The
1722 * **BPF_F_INGRESS** value in *flags* is used to make the
1723 * distinction (ingress path is selected if the flag is present,
1724 * egress path otherwise). This is the only flag supported for now.
1726 * **SK_PASS** on success, or **SK_DROP** on error.
1728 * int bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
1730 * For socket policies, apply the verdict of the eBPF program to
1731 * the next *bytes* (number of bytes) of message *msg*.
1733 * For example, this helper can be used in the following cases:
1735 * * A single **sendmsg**\ () or **sendfile**\ () system call
1736 * contains multiple logical messages that the eBPF program is
1737 * supposed to read and for which it should apply a verdict.
1738 * * An eBPF program only cares to read the first *bytes* of a
1739 * *msg*. If the message has a large payload, then setting up
1740 * and calling the eBPF program repeatedly for all bytes, even
1741 * though the verdict is already known, would create unnecessary
1744 * When called from within an eBPF program, the helper sets a
1745 * counter internal to the BPF infrastructure, that is used to
1746 * apply the last verdict to the next *bytes*. If *bytes* is
1747 * smaller than the current data being processed from a
1748 * **sendmsg**\ () or **sendfile**\ () system call, the first
1749 * *bytes* will be sent and the eBPF program will be re-run with
1750 * the pointer for start of data pointing to byte number *bytes*
1751 * **+ 1**. If *bytes* is larger than the current data being
1752 * processed, then the eBPF verdict will be applied to multiple
1753 * **sendmsg**\ () or **sendfile**\ () calls until *bytes* are
1756 * Note that if a socket closes with the internal counter holding
1757 * a non-zero value, this is not a problem because data is not
1758 * being buffered for *bytes* and is sent as it is received.
1762 * int bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
1764 * For socket policies, prevent the execution of the verdict eBPF
1765 * program for message *msg* until *bytes* (byte number) have been
1768 * This can be used when one needs a specific number of bytes
1769 * before a verdict can be assigned, even if the data spans
1770 * multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
1771 * case would be a user calling **sendmsg**\ () repeatedly with
1772 * 1-byte long message segments. Obviously, this is bad for
1773 * performance, but it is still valid. If the eBPF program needs
1774 * *bytes* bytes to validate a header, this helper can be used to
1775 * prevent the eBPF program to be called again until *bytes* have
1780 * int bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
1782 * For socket policies, pull in non-linear data from user space
1783 * for *msg* and set pointers *msg*\ **->data** and *msg*\
1784 * **->data_end** to *start* and *end* bytes offsets into *msg*,
1787 * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
1788 * *msg* it can only parse data that the (**data**, **data_end**)
1789 * pointers have already consumed. For **sendmsg**\ () hooks this
1790 * is likely the first scatterlist element. But for calls relying
1791 * on the **sendpage** handler (e.g. **sendfile**\ ()) this will
1792 * be the range (**0**, **0**) because the data is shared with
1793 * user space and by default the objective is to avoid allowing
1794 * user space to modify data while (or after) eBPF verdict is
1795 * being decided. This helper can be used to pull in data and to
1796 * set the start and end pointer to given values. Data will be
1797 * copied if necessary (i.e. if data was not linear and if start
1798 * and end pointers do not point to the same chunk).
1800 * A call to this helper is susceptible to change the underlaying
1801 * packet buffer. Therefore, at load time, all checks on pointers
1802 * previously done by the verifier are invalidated and must be
1803 * performed again, if the helper is used in combination with
1804 * direct packet access.
1806 * All values for *flags* are reserved for future usage, and must
1809 * 0 on success, or a negative error in case of failure.
1811 * int bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
1813 * Bind the socket associated to *ctx* to the address pointed by
1814 * *addr*, of length *addr_len*. This allows for making outgoing
1815 * connection from the desired IP address, which can be useful for
1816 * example when all processes inside a cgroup should use one
1817 * single IP address on a host that has multiple IP configured.
1819 * This helper works for IPv4 and IPv6, TCP and UDP sockets. The
1820 * domain (*addr*\ **->sa_family**) must be **AF_INET** (or
1821 * **AF_INET6**). Looking for a free port to bind to can be
1822 * expensive, therefore binding to port is not permitted by the
1823 * helper: *addr*\ **->sin_port** (or **sin6_port**, respectively)
1824 * must be set to zero.
1826 * 0 on success, or a negative error in case of failure.
1828 * int bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
1830 * Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
1831 * only possible to shrink the packet as of this writing,
1832 * therefore *delta* must be a negative integer.
1834 * A call to this helper is susceptible to change the underlaying
1835 * packet buffer. Therefore, at load time, all checks on pointers
1836 * previously done by the verifier are invalidated and must be
1837 * performed again, if the helper is used in combination with
1838 * direct packet access.
1840 * 0 on success, or a negative error in case of failure.
1842 * int bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
1844 * Retrieve the XFRM state (IP transform framework, see also
1845 * **ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
1847 * The retrieved value is stored in the **struct bpf_xfrm_state**
1848 * pointed by *xfrm_state* and of length *size*.
1850 * All values for *flags* are reserved for future usage, and must
1853 * This helper is available only if the kernel was compiled with
1854 * **CONFIG_XFRM** configuration option.
1856 * 0 on success, or a negative error in case of failure.
1858 * int bpf_get_stack(struct pt_regs *regs, void *buf, u32 size, u64 flags)
1860 * Return a user or a kernel stack in bpf program provided buffer.
1861 * To achieve this, the helper needs *ctx*, which is a pointer
1862 * to the context on which the tracing program is executed.
1863 * To store the stacktrace, the bpf program provides *buf* with
1864 * a nonnegative *size*.
1866 * The last argument, *flags*, holds the number of stack frames to
1867 * skip (from 0 to 255), masked with
1868 * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
1869 * the following flags:
1871 * **BPF_F_USER_STACK**
1872 * Collect a user space stack instead of a kernel stack.
1873 * **BPF_F_USER_BUILD_ID**
1874 * Collect buildid+offset instead of ips for user stack,
1875 * only valid if **BPF_F_USER_STACK** is also specified.
1877 * **bpf_get_stack**\ () can collect up to
1878 * **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
1879 * to sufficient large buffer size. Note that
1880 * this limit can be controlled with the **sysctl** program, and
1881 * that it should be manually increased in order to profile long
1882 * user stacks (such as stacks for Java programs). To do so, use:
1886 * # sysctl kernel.perf_event_max_stack=<new value>
1888 * A non-negative value equal to or less than *size* on success,
1889 * or a negative error in case of failure.
1891 * int bpf_skb_load_bytes_relative(const struct sk_buff *skb, u32 offset, void *to, u32 len, u32 start_header)
1893 * This helper is similar to **bpf_skb_load_bytes**\ () in that
1894 * it provides an easy way to load *len* bytes from *offset*
1895 * from the packet associated to *skb*, into the buffer pointed
1896 * by *to*. The difference to **bpf_skb_load_bytes**\ () is that
1897 * a fifth argument *start_header* exists in order to select a
1898 * base offset to start from. *start_header* can be one of:
1900 * **BPF_HDR_START_MAC**
1901 * Base offset to load data from is *skb*'s mac header.
1902 * **BPF_HDR_START_NET**
1903 * Base offset to load data from is *skb*'s network header.
1905 * In general, "direct packet access" is the preferred method to
1906 * access packet data, however, this helper is in particular useful
1907 * in socket filters where *skb*\ **->data** does not always point
1908 * to the start of the mac header and where "direct packet access"
1911 * 0 on success, or a negative error in case of failure.
1913 * int bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
1915 * Do FIB lookup in kernel tables using parameters in *params*.
1916 * If lookup is successful and result shows packet is to be
1917 * forwarded, the neighbor tables are searched for the nexthop.
1918 * If successful (ie., FIB lookup shows forwarding and nexthop
1919 * is resolved), the nexthop address is returned in ipv4_dst
1920 * or ipv6_dst based on family, smac is set to mac address of
1921 * egress device, dmac is set to nexthop mac address, rt_metric
1922 * is set to metric from route (IPv4/IPv6 only), and ifindex
1923 * is set to the device index of the nexthop from the FIB lookup.
1925 * *plen* argument is the size of the passed in struct.
1926 * *flags* argument can be a combination of one or more of the
1929 * **BPF_FIB_LOOKUP_DIRECT**
1930 * Do a direct table lookup vs full lookup using FIB
1932 * **BPF_FIB_LOOKUP_OUTPUT**
1933 * Perform lookup from an egress perspective (default is
1936 * *ctx* is either **struct xdp_md** for XDP programs or
1937 * **struct sk_buff** tc cls_act programs.
1939 * * < 0 if any input argument is invalid
1940 * * 0 on success (packet is forwarded, nexthop neighbor exists)
1941 * * > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
1942 * packet is not forwarded or needs assist from full stack
1944 * int bpf_sock_hash_update(struct bpf_sock_ops_kern *skops, struct bpf_map *map, void *key, u64 flags)
1946 * Add an entry to, or update a sockhash *map* referencing sockets.
1947 * The *skops* is used as a new value for the entry associated to
1948 * *key*. *flags* is one of:
1951 * The entry for *key* must not exist in the map.
1953 * The entry for *key* must already exist in the map.
1955 * No condition on the existence of the entry for *key*.
1957 * If the *map* has eBPF programs (parser and verdict), those will
1958 * be inherited by the socket being added. If the socket is
1959 * already attached to eBPF programs, this results in an error.
1961 * 0 on success, or a negative error in case of failure.
1963 * int bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
1965 * This helper is used in programs implementing policies at the
1966 * socket level. If the message *msg* is allowed to pass (i.e. if
1967 * the verdict eBPF program returns **SK_PASS**), redirect it to
1968 * the socket referenced by *map* (of type
1969 * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
1970 * egress interfaces can be used for redirection. The
1971 * **BPF_F_INGRESS** value in *flags* is used to make the
1972 * distinction (ingress path is selected if the flag is present,
1973 * egress path otherwise). This is the only flag supported for now.
1975 * **SK_PASS** on success, or **SK_DROP** on error.
1977 * int bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
1979 * This helper is used in programs implementing policies at the
1980 * skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
1981 * if the verdeict eBPF program returns **SK_PASS**), redirect it
1982 * to the socket referenced by *map* (of type
1983 * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
1984 * egress interfaces can be used for redirection. The
1985 * **BPF_F_INGRESS** value in *flags* is used to make the
1986 * distinction (ingress path is selected if the flag is present,
1987 * egress otherwise). This is the only flag supported for now.
1989 * **SK_PASS** on success, or **SK_DROP** on error.
1991 * int bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
1993 * Encapsulate the packet associated to *skb* within a Layer 3
1994 * protocol header. This header is provided in the buffer at
1995 * address *hdr*, with *len* its size in bytes. *type* indicates
1996 * the protocol of the header and can be one of:
1998 * **BPF_LWT_ENCAP_SEG6**
1999 * IPv6 encapsulation with Segment Routing Header
2000 * (**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
2001 * the IPv6 header is computed by the kernel.
2002 * **BPF_LWT_ENCAP_SEG6_INLINE**
2003 * Only works if *skb* contains an IPv6 packet. Insert a
2004 * Segment Routing Header (**struct ipv6_sr_hdr**) inside
2007 * A call to this helper is susceptible to change the underlaying
2008 * packet buffer. Therefore, at load time, all checks on pointers
2009 * previously done by the verifier are invalidated and must be
2010 * performed again, if the helper is used in combination with
2011 * direct packet access.
2013 * 0 on success, or a negative error in case of failure.
2015 * int bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
2017 * Store *len* bytes from address *from* into the packet
2018 * associated to *skb*, at *offset*. Only the flags, tag and TLVs
2019 * inside the outermost IPv6 Segment Routing Header can be
2020 * modified through this helper.
2022 * A call to this helper is susceptible to change the underlaying
2023 * packet buffer. Therefore, at load time, all checks on pointers
2024 * previously done by the verifier are invalidated and must be
2025 * performed again, if the helper is used in combination with
2026 * direct packet access.
2028 * 0 on success, or a negative error in case of failure.
2030 * int bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
2032 * Adjust the size allocated to TLVs in the outermost IPv6
2033 * Segment Routing Header contained in the packet associated to
2034 * *skb*, at position *offset* by *delta* bytes. Only offsets
2035 * after the segments are accepted. *delta* can be as well
2036 * positive (growing) as negative (shrinking).
2038 * A call to this helper is susceptible to change the underlaying
2039 * packet buffer. Therefore, at load time, all checks on pointers
2040 * previously done by the verifier are invalidated and must be
2041 * performed again, if the helper is used in combination with
2042 * direct packet access.
2044 * 0 on success, or a negative error in case of failure.
2046 * int bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
2048 * Apply an IPv6 Segment Routing action of type *action* to the
2049 * packet associated to *skb*. Each action takes a parameter
2050 * contained at address *param*, and of length *param_len* bytes.
2051 * *action* can be one of:
2053 * **SEG6_LOCAL_ACTION_END_X**
2054 * End.X action: Endpoint with Layer-3 cross-connect.
2055 * Type of *param*: **struct in6_addr**.
2056 * **SEG6_LOCAL_ACTION_END_T**
2057 * End.T action: Endpoint with specific IPv6 table lookup.
2058 * Type of *param*: **int**.
2059 * **SEG6_LOCAL_ACTION_END_B6**
2060 * End.B6 action: Endpoint bound to an SRv6 policy.
2061 * Type of param: **struct ipv6_sr_hdr**.
2062 * **SEG6_LOCAL_ACTION_END_B6_ENCAP**
2063 * End.B6.Encap action: Endpoint bound to an SRv6
2064 * encapsulation policy.
2065 * Type of param: **struct ipv6_sr_hdr**.
2067 * A call to this helper is susceptible to change the underlaying
2068 * packet buffer. Therefore, at load time, all checks on pointers
2069 * previously done by the verifier are invalidated and must be
2070 * performed again, if the helper is used in combination with
2071 * direct packet access.
2073 * 0 on success, or a negative error in case of failure.
2075 * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
2077 * This helper is used in programs implementing IR decoding, to
2078 * report a successfully decoded key press with *scancode*,
2079 * *toggle* value in the given *protocol*. The scancode will be
2080 * translated to a keycode using the rc keymap, and reported as
2081 * an input key down event. After a period a key up event is
2082 * generated. This period can be extended by calling either
2083 * **bpf_rc_keydown**\ () again with the same values, or calling
2084 * **bpf_rc_repeat**\ ().
2086 * Some protocols include a toggle bit, in case the button was
2087 * released and pressed again between consecutive scancodes.
2089 * The *ctx* should point to the lirc sample as passed into
2092 * The *protocol* is the decoded protocol number (see
2093 * **enum rc_proto** for some predefined values).
2095 * This helper is only available is the kernel was compiled with
2096 * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
2101 * int bpf_rc_repeat(void *ctx)
2103 * This helper is used in programs implementing IR decoding, to
2104 * report a successfully decoded repeat key message. This delays
2105 * the generation of a key up event for previously generated
2108 * Some IR protocols like NEC have a special IR message for
2109 * repeating last button, for when a button is held down.
2111 * The *ctx* should point to the lirc sample as passed into
2114 * This helper is only available is the kernel was compiled with
2115 * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
2120 * uint64_t bpf_skb_cgroup_id(struct sk_buff *skb)
2122 * Return the cgroup v2 id of the socket associated with the *skb*.
2123 * This is roughly similar to the **bpf_get_cgroup_classid**\ ()
2124 * helper for cgroup v1 by providing a tag resp. identifier that
2125 * can be matched on or used for map lookups e.g. to implement
2126 * policy. The cgroup v2 id of a given path in the hierarchy is
2127 * exposed in user space through the f_handle API in order to get
2128 * to the same 64-bit id.
2130 * This helper can be used on TC egress path, but not on ingress,
2131 * and is available only if the kernel was compiled with the
2132 * **CONFIG_SOCK_CGROUP_DATA** configuration option.
2134 * The id is returned or 0 in case the id could not be retrieved.
2136 * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
2138 * Return id of cgroup v2 that is ancestor of cgroup associated
2139 * with the *skb* at the *ancestor_level*. The root cgroup is at
2140 * *ancestor_level* zero and each step down the hierarchy
2141 * increments the level. If *ancestor_level* == level of cgroup
2142 * associated with *skb*, then return value will be same as that
2143 * of **bpf_skb_cgroup_id**\ ().
2145 * The helper is useful to implement policies based on cgroups
2146 * that are upper in hierarchy than immediate cgroup associated
2149 * The format of returned id and helper limitations are same as in
2150 * **bpf_skb_cgroup_id**\ ().
2152 * The id is returned or 0 in case the id could not be retrieved.
2154 * u64 bpf_get_current_cgroup_id(void)
2156 * A 64-bit integer containing the current cgroup id based
2157 * on the cgroup within which the current task is running.
2159 * void* get_local_storage(void *map, u64 flags)
2161 * Get the pointer to the local storage area.
2162 * The type and the size of the local storage is defined
2163 * by the *map* argument.
2164 * The *flags* meaning is specific for each map type,
2165 * and has to be 0 for cgroup local storage.
2167 * Depending on the BPF program type, a local storage area
2168 * can be shared between multiple instances of the BPF program,
2169 * running simultaneously.
2171 * A user should care about the synchronization by himself.
2172 * For example, by using the **BPF_STX_XADD** instruction to alter
2175 * A pointer to the local storage area.
2177 * int bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
2179 * Select a **SO_REUSEPORT** socket from a
2180 * **BPF_MAP_TYPE_REUSEPORT_ARRAY** *map*.
2181 * It checks the selected socket is matching the incoming
2182 * request in the socket buffer.
2184 * 0 on success, or a negative error in case of failure.
2186 * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u32 netns, u64 flags)
2188 * Look for TCP socket matching *tuple*, optionally in a child
2189 * network namespace *netns*. The return value must be checked,
2190 * and if non-**NULL**, released via **bpf_sk_release**\ ().
2192 * The *ctx* should point to the context of the program, such as
2193 * the skb or socket (depending on the hook in use). This is used
2194 * to determine the base network namespace for the lookup.
2196 * *tuple_size* must be one of:
2198 * **sizeof**\ (*tuple*\ **->ipv4**)
2199 * Look for an IPv4 socket.
2200 * **sizeof**\ (*tuple*\ **->ipv6**)
2201 * Look for an IPv6 socket.
2203 * If the *netns* is zero, then the socket lookup table in the
2204 * netns associated with the *ctx* will be used. For the TC hooks,
2205 * this in the netns of the device in the skb. For socket hooks,
2206 * this in the netns of the socket. If *netns* is non-zero, then
2207 * it specifies the ID of the netns relative to the netns
2208 * associated with the *ctx*.
2210 * All values for *flags* are reserved for future usage, and must
2213 * This helper is available only if the kernel was compiled with
2214 * **CONFIG_NET** configuration option.
2216 * A pointer to *struct bpf_sock*, or **NULL** in case of failure.
2217 * For sockets with reuseport option, **struct bpf_sock**
2218 * return is from **reuse->socks**\ [] using hash of the packet.
2220 * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u32 netns, u64 flags)
2222 * Look for UDP socket matching *tuple*, optionally in a child
2223 * network namespace *netns*. The return value must be checked,
2224 * and if non-**NULL**, released via **bpf_sk_release**\ ().
2226 * The *ctx* should point to the context of the program, such as
2227 * the skb or socket (depending on the hook in use). This is used
2228 * to determine the base network namespace for the lookup.
2230 * *tuple_size* must be one of:
2232 * **sizeof**\ (*tuple*\ **->ipv4**)
2233 * Look for an IPv4 socket.
2234 * **sizeof**\ (*tuple*\ **->ipv6**)
2235 * Look for an IPv6 socket.
2237 * If the *netns* is zero, then the socket lookup table in the
2238 * netns associated with the *ctx* will be used. For the TC hooks,
2239 * this in the netns of the device in the skb. For socket hooks,
2240 * this in the netns of the socket. If *netns* is non-zero, then
2241 * it specifies the ID of the netns relative to the netns
2242 * associated with the *ctx*.
2244 * All values for *flags* are reserved for future usage, and must
2247 * This helper is available only if the kernel was compiled with
2248 * **CONFIG_NET** configuration option.
2250 * A pointer to **struct bpf_sock**, or **NULL** in case of
2251 * failure. For sockets with reuseport option, **struct bpf_sock**
2252 * return is from **reuse->socks**\ [] using hash of the packet.
2254 * int bpf_sk_release(struct bpf_sock *sock)
2256 * Release the reference held by *sock*. *sock* must be a
2257 * non-**NULL** pointer that was returned from
2258 * **bpf_sk_lookup_xxx**\ ().
2260 * 0 on success, or a negative error in case of failure.
2262 * int bpf_map_pop_elem(struct bpf_map *map, void *value)
2264 * Pop an element from *map*.
2266 * 0 on success, or a negative error in case of failure.
2268 * int bpf_map_peek_elem(struct bpf_map *map, void *value)
2270 * Get an element from *map* without removing it.
2272 * 0 on success, or a negative error in case of failure.
2274 * int bpf_msg_push_data(struct sk_buff *skb, u32 start, u32 len, u64 flags)
2276 * For socket policies, insert *len* bytes into *msg* at offset
2279 * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
2280 * *msg* it may want to insert metadata or options into the *msg*.
2281 * This can later be read and used by any of the lower layer BPF
2284 * This helper may fail if under memory pressure (a malloc
2285 * fails) in these cases BPF programs will get an appropriate
2286 * error and BPF programs will need to handle them.
2288 * 0 on success, or a negative error in case of failure.
2290 * int bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 pop, u64 flags)
2292 * Will remove *pop* bytes from a *msg* starting at byte *start*.
2293 * This may result in **ENOMEM** errors under certain situations if
2294 * an allocation and copy are required due to a full ring buffer.
2295 * However, the helper will try to avoid doing the allocation
2296 * if possible. Other errors can occur if input parameters are
2297 * invalid either due to *start* byte not being valid part of *msg*
2298 * payload and/or *pop* value being to large.
2300 * 0 on success, or a negative error in case of failure.
2302 #define __BPF_FUNC_MAPPER(FN) \
2304 FN(map_lookup_elem), \
2305 FN(map_update_elem), \
2306 FN(map_delete_elem), \
2310 FN(get_prandom_u32), \
2311 FN(get_smp_processor_id), \
2312 FN(skb_store_bytes), \
2313 FN(l3_csum_replace), \
2314 FN(l4_csum_replace), \
2316 FN(clone_redirect), \
2317 FN(get_current_pid_tgid), \
2318 FN(get_current_uid_gid), \
2319 FN(get_current_comm), \
2320 FN(get_cgroup_classid), \
2321 FN(skb_vlan_push), \
2323 FN(skb_get_tunnel_key), \
2324 FN(skb_set_tunnel_key), \
2325 FN(perf_event_read), \
2327 FN(get_route_realm), \
2328 FN(perf_event_output), \
2329 FN(skb_load_bytes), \
2332 FN(skb_get_tunnel_opt), \
2333 FN(skb_set_tunnel_opt), \
2334 FN(skb_change_proto), \
2335 FN(skb_change_type), \
2336 FN(skb_under_cgroup), \
2337 FN(get_hash_recalc), \
2338 FN(get_current_task), \
2339 FN(probe_write_user), \
2340 FN(current_task_under_cgroup), \
2341 FN(skb_change_tail), \
2342 FN(skb_pull_data), \
2344 FN(set_hash_invalid), \
2345 FN(get_numa_node_id), \
2346 FN(skb_change_head), \
2347 FN(xdp_adjust_head), \
2348 FN(probe_read_str), \
2349 FN(get_socket_cookie), \
2350 FN(get_socket_uid), \
2353 FN(skb_adjust_room), \
2355 FN(sk_redirect_map), \
2356 FN(sock_map_update), \
2357 FN(xdp_adjust_meta), \
2358 FN(perf_event_read_value), \
2359 FN(perf_prog_read_value), \
2361 FN(override_return), \
2362 FN(sock_ops_cb_flags_set), \
2363 FN(msg_redirect_map), \
2364 FN(msg_apply_bytes), \
2365 FN(msg_cork_bytes), \
2366 FN(msg_pull_data), \
2368 FN(xdp_adjust_tail), \
2369 FN(skb_get_xfrm_state), \
2371 FN(skb_load_bytes_relative), \
2373 FN(sock_hash_update), \
2374 FN(msg_redirect_hash), \
2375 FN(sk_redirect_hash), \
2376 FN(lwt_push_encap), \
2377 FN(lwt_seg6_store_bytes), \
2378 FN(lwt_seg6_adjust_srh), \
2379 FN(lwt_seg6_action), \
2382 FN(skb_cgroup_id), \
2383 FN(get_current_cgroup_id), \
2384 FN(get_local_storage), \
2385 FN(sk_select_reuseport), \
2386 FN(skb_ancestor_cgroup_id), \
2387 FN(sk_lookup_tcp), \
2388 FN(sk_lookup_udp), \
2390 FN(map_push_elem), \
2392 FN(map_peek_elem), \
2393 FN(msg_push_data), \
2396 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
2397 * function eBPF program intends to call
2399 #define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
2401 __BPF_FUNC_MAPPER(__BPF_ENUM_FN)
2404 #undef __BPF_ENUM_FN
2406 /* All flags used by eBPF helper functions, placed here. */
2408 /* BPF_FUNC_skb_store_bytes flags. */
2409 #define BPF_F_RECOMPUTE_CSUM (1ULL << 0)
2410 #define BPF_F_INVALIDATE_HASH (1ULL << 1)
2412 /* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
2413 * First 4 bits are for passing the header field size.
2415 #define BPF_F_HDR_FIELD_MASK 0xfULL
2417 /* BPF_FUNC_l4_csum_replace flags. */
2418 #define BPF_F_PSEUDO_HDR (1ULL << 4)
2419 #define BPF_F_MARK_MANGLED_0 (1ULL << 5)
2420 #define BPF_F_MARK_ENFORCE (1ULL << 6)
2422 /* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
2423 #define BPF_F_INGRESS (1ULL << 0)
2425 /* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
2426 #define BPF_F_TUNINFO_IPV6 (1ULL << 0)
2428 /* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
2429 #define BPF_F_SKIP_FIELD_MASK 0xffULL
2430 #define BPF_F_USER_STACK (1ULL << 8)
2431 /* flags used by BPF_FUNC_get_stackid only. */
2432 #define BPF_F_FAST_STACK_CMP (1ULL << 9)
2433 #define BPF_F_REUSE_STACKID (1ULL << 10)
2434 /* flags used by BPF_FUNC_get_stack only. */
2435 #define BPF_F_USER_BUILD_ID (1ULL << 11)
2437 /* BPF_FUNC_skb_set_tunnel_key flags. */
2438 #define BPF_F_ZERO_CSUM_TX (1ULL << 1)
2439 #define BPF_F_DONT_FRAGMENT (1ULL << 2)
2440 #define BPF_F_SEQ_NUMBER (1ULL << 3)
2442 /* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
2443 * BPF_FUNC_perf_event_read_value flags.
2445 #define BPF_F_INDEX_MASK 0xffffffffULL
2446 #define BPF_F_CURRENT_CPU BPF_F_INDEX_MASK
2447 /* BPF_FUNC_perf_event_output for sk_buff input context. */
2448 #define BPF_F_CTXLEN_MASK (0xfffffULL << 32)
2450 /* Mode for BPF_FUNC_skb_adjust_room helper. */
2451 enum bpf_adj_room_mode {
2455 /* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
2456 enum bpf_hdr_start_off {
2461 /* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
2462 enum bpf_lwt_encap_mode {
2464 BPF_LWT_ENCAP_SEG6_INLINE
2467 /* user accessible mirror of in-kernel sk_buff.
2468 * new fields can only be added to the end of this structure
2474 __u32 queue_mapping;
2480 __u32 ingress_ifindex;
2490 /* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
2492 __u32 remote_ip4; /* Stored in network byte order */
2493 __u32 local_ip4; /* Stored in network byte order */
2494 __u32 remote_ip6[4]; /* Stored in network byte order */
2495 __u32 local_ip6[4]; /* Stored in network byte order */
2496 __u32 remote_port; /* Stored in network byte order */
2497 __u32 local_port; /* stored in host byte order */
2501 struct bpf_flow_keys *flow_keys;
2506 struct bpf_tunnel_key {
2510 __u32 remote_ipv6[4];
2514 __u16 tunnel_ext; /* Padding, future use. */
2518 /* user accessible mirror of in-kernel xfrm_state.
2519 * new fields can only be added to the end of this structure
2521 struct bpf_xfrm_state {
2523 __u32 spi; /* Stored in network byte order */
2525 __u16 ext; /* Padding, future use. */
2527 __u32 remote_ipv4; /* Stored in network byte order */
2528 __u32 remote_ipv6[4]; /* Stored in network byte order */
2532 /* Generic BPF return codes which all BPF program types may support.
2533 * The values are binary compatible with their TC_ACT_* counter-part to
2534 * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
2537 * XDP is handled seprately, see XDP_*.
2545 /* >127 are reserved for prog type specific return codes */
2555 __u32 src_ip4; /* Allows 1,2,4-byte read.
2556 * Stored in network byte order.
2558 __u32 src_ip6[4]; /* Allows 1,2,4-byte read.
2559 * Stored in network byte order.
2561 __u32 src_port; /* Allows 4-byte read.
2562 * Stored in host byte order
2566 struct bpf_sock_tuple {
2583 #define XDP_PACKET_HEADROOM 256
2585 /* User return codes for XDP prog type.
2586 * A valid XDP program must return one of these defined values. All other
2587 * return codes are reserved for future use. Unknown return codes will
2588 * result in packet drops and a warning via bpf_warn_invalid_xdp_action().
2598 /* user accessible metadata for XDP packet hook
2599 * new fields must be added to the end of this structure
2605 /* Below access go through struct xdp_rxq_info */
2606 __u32 ingress_ifindex; /* rxq->dev->ifindex */
2607 __u32 rx_queue_index; /* rxq->queue_index */
2615 /* user accessible metadata for SK_MSG packet hook, new fields must
2616 * be added to the end of this structure
2623 __u32 remote_ip4; /* Stored in network byte order */
2624 __u32 local_ip4; /* Stored in network byte order */
2625 __u32 remote_ip6[4]; /* Stored in network byte order */
2626 __u32 local_ip6[4]; /* Stored in network byte order */
2627 __u32 remote_port; /* Stored in network byte order */
2628 __u32 local_port; /* stored in host byte order */
2631 struct sk_reuseport_md {
2633 * Start of directly accessible data. It begins from
2634 * the tcp/udp header.
2637 void *data_end; /* End of directly accessible data */
2639 * Total length of packet (starting from the tcp/udp header).
2640 * Note that the directly accessible bytes (data_end - data)
2641 * could be less than this "len". Those bytes could be
2642 * indirectly read by a helper "bpf_skb_load_bytes()".
2646 * Eth protocol in the mac header (network byte order). e.g.
2647 * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
2650 __u32 ip_protocol; /* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
2651 __u32 bind_inany; /* Is sock bound to an INANY address? */
2652 __u32 hash; /* A hash of the packet 4 tuples */
2655 #define BPF_TAG_SIZE 8
2657 struct bpf_prog_info {
2660 __u8 tag[BPF_TAG_SIZE];
2661 __u32 jited_prog_len;
2662 __u32 xlated_prog_len;
2663 __aligned_u64 jited_prog_insns;
2664 __aligned_u64 xlated_prog_insns;
2665 __u64 load_time; /* ns since boottime */
2666 __u32 created_by_uid;
2668 __aligned_u64 map_ids;
2669 char name[BPF_OBJ_NAME_LEN];
2671 __u32 gpl_compatible:1;
2674 __u32 nr_jited_ksyms;
2675 __u32 nr_jited_func_lens;
2676 __aligned_u64 jited_ksyms;
2677 __aligned_u64 jited_func_lens;
2679 __u32 func_info_rec_size;
2680 __aligned_u64 func_info;
2681 __u32 func_info_cnt;
2682 } __attribute__((aligned(8)));
2684 struct bpf_map_info {
2691 char name[BPF_OBJ_NAME_LEN];
2697 __u32 btf_key_type_id;
2698 __u32 btf_value_type_id;
2699 } __attribute__((aligned(8)));
2701 struct bpf_btf_info {
2705 } __attribute__((aligned(8)));
2707 /* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
2708 * by user and intended to be used by socket (e.g. to bind to, depends on
2709 * attach attach type).
2711 struct bpf_sock_addr {
2712 __u32 user_family; /* Allows 4-byte read, but no write. */
2713 __u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write.
2714 * Stored in network byte order.
2716 __u32 user_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write.
2717 * Stored in network byte order.
2719 __u32 user_port; /* Allows 4-byte read and write.
2720 * Stored in network byte order
2722 __u32 family; /* Allows 4-byte read, but no write */
2723 __u32 type; /* Allows 4-byte read, but no write */
2724 __u32 protocol; /* Allows 4-byte read, but no write */
2725 __u32 msg_src_ip4; /* Allows 1,2,4-byte read an 4-byte write.
2726 * Stored in network byte order.
2728 __u32 msg_src_ip6[4]; /* Allows 1,2,4-byte read an 4-byte write.
2729 * Stored in network byte order.
2733 /* User bpf_sock_ops struct to access socket values and specify request ops
2734 * and their replies.
2735 * Some of this fields are in network (bigendian) byte order and may need
2736 * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
2737 * New fields can only be added at the end of this structure
2739 struct bpf_sock_ops {
2742 __u32 args[4]; /* Optionally passed to bpf program */
2743 __u32 reply; /* Returned by bpf program */
2744 __u32 replylong[4]; /* Optionally returned by bpf prog */
2747 __u32 remote_ip4; /* Stored in network byte order */
2748 __u32 local_ip4; /* Stored in network byte order */
2749 __u32 remote_ip6[4]; /* Stored in network byte order */
2750 __u32 local_ip6[4]; /* Stored in network byte order */
2751 __u32 remote_port; /* Stored in network byte order */
2752 __u32 local_port; /* stored in host byte order */
2753 __u32 is_fullsock; /* Some TCP fields are only valid if
2754 * there is a full socket. If not, the
2755 * fields read as zero.
2758 __u32 srtt_us; /* Averaged RTT << 3 in usecs */
2759 __u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
2768 __u32 rate_delivered;
2769 __u32 rate_interval_us;
2772 __u32 total_retrans;
2776 __u32 data_segs_out;
2780 __u64 bytes_received;
2784 /* Definitions for bpf_sock_ops_cb_flags */
2785 #define BPF_SOCK_OPS_RTO_CB_FLAG (1<<0)
2786 #define BPF_SOCK_OPS_RETRANS_CB_FLAG (1<<1)
2787 #define BPF_SOCK_OPS_STATE_CB_FLAG (1<<2)
2788 #define BPF_SOCK_OPS_ALL_CB_FLAGS 0x7 /* Mask of all currently
2789 * supported cb flags
2792 /* List of known BPF sock_ops operators.
2793 * New entries can only be added at the end
2797 BPF_SOCK_OPS_TIMEOUT_INIT, /* Should return SYN-RTO value to use or
2798 * -1 if default value should be used
2800 BPF_SOCK_OPS_RWND_INIT, /* Should return initial advertized
2801 * window (in packets) or -1 if default
2802 * value should be used
2804 BPF_SOCK_OPS_TCP_CONNECT_CB, /* Calls BPF program right before an
2805 * active connection is initialized
2807 BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB, /* Calls BPF program when an
2808 * active connection is
2811 BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, /* Calls BPF program when a
2812 * passive connection is
2815 BPF_SOCK_OPS_NEEDS_ECN, /* If connection's congestion control
2818 BPF_SOCK_OPS_BASE_RTT, /* Get base RTT. The correct value is
2819 * based on the path and may be
2820 * dependent on the congestion control
2821 * algorithm. In general it indicates
2822 * a congestion threshold. RTTs above
2823 * this indicate congestion
2825 BPF_SOCK_OPS_RTO_CB, /* Called when an RTO has triggered.
2826 * Arg1: value of icsk_retransmits
2827 * Arg2: value of icsk_rto
2828 * Arg3: whether RTO has expired
2830 BPF_SOCK_OPS_RETRANS_CB, /* Called when skb is retransmitted.
2831 * Arg1: sequence number of 1st byte
2833 * Arg3: return value of
2834 * tcp_transmit_skb (0 => success)
2836 BPF_SOCK_OPS_STATE_CB, /* Called when TCP changes state.
2840 BPF_SOCK_OPS_TCP_LISTEN_CB, /* Called on listen(2), right after
2841 * socket transition to LISTEN state.
2845 /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
2846 * changes between the TCP and BPF versions. Ideally this should never happen.
2847 * If it does, we need to add code to convert them before calling
2848 * the BPF sock_ops function.
2851 BPF_TCP_ESTABLISHED = 1,
2861 BPF_TCP_CLOSING, /* Now a valid state */
2862 BPF_TCP_NEW_SYN_RECV,
2864 BPF_TCP_MAX_STATES /* Leave at the end! */
2867 #define TCP_BPF_IW 1001 /* Set TCP initial congestion window */
2868 #define TCP_BPF_SNDCWND_CLAMP 1002 /* Set sndcwnd_clamp */
2870 struct bpf_perf_event_value {
2876 #define BPF_DEVCG_ACC_MKNOD (1ULL << 0)
2877 #define BPF_DEVCG_ACC_READ (1ULL << 1)
2878 #define BPF_DEVCG_ACC_WRITE (1ULL << 2)
2880 #define BPF_DEVCG_DEV_BLOCK (1ULL << 0)
2881 #define BPF_DEVCG_DEV_CHAR (1ULL << 1)
2883 struct bpf_cgroup_dev_ctx {
2884 /* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
2890 struct bpf_raw_tracepoint_args {
2894 /* DIRECT: Skip the FIB rules and go to FIB table associated with device
2895 * OUTPUT: Do lookup from egress perspective; default is ingress
2897 #define BPF_FIB_LOOKUP_DIRECT BIT(0)
2898 #define BPF_FIB_LOOKUP_OUTPUT BIT(1)
2901 BPF_FIB_LKUP_RET_SUCCESS, /* lookup successful */
2902 BPF_FIB_LKUP_RET_BLACKHOLE, /* dest is blackholed; can be dropped */
2903 BPF_FIB_LKUP_RET_UNREACHABLE, /* dest is unreachable; can be dropped */
2904 BPF_FIB_LKUP_RET_PROHIBIT, /* dest not allowed; can be dropped */
2905 BPF_FIB_LKUP_RET_NOT_FWDED, /* packet is not forwarded */
2906 BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
2907 BPF_FIB_LKUP_RET_UNSUPP_LWT, /* fwd requires encapsulation */
2908 BPF_FIB_LKUP_RET_NO_NEIGH, /* no neighbor entry for nh */
2909 BPF_FIB_LKUP_RET_FRAG_NEEDED, /* fragmentation required to fwd */
2912 struct bpf_fib_lookup {
2913 /* input: network family for lookup (AF_INET, AF_INET6)
2914 * output: network family of egress nexthop
2918 /* set if lookup is to consider L4 data - e.g., FIB rules */
2923 /* total length of packet from network header - used for MTU check */
2926 /* input: L3 device index for lookup
2927 * output: device index from FIB lookup
2932 /* inputs to lookup */
2933 __u8 tos; /* AF_INET */
2934 __be32 flowinfo; /* AF_INET6, flow_label + priority */
2936 /* output: metric of fib result (IPv4/IPv6 only) */
2942 __u32 ipv6_src[4]; /* in6_addr; network order */
2945 /* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
2946 * network header. output: bpf_fib_lookup sets to gateway address
2947 * if FIB lookup returns gateway route
2951 __u32 ipv6_dst[4]; /* in6_addr; network order */
2955 __be16 h_vlan_proto;
2957 __u8 smac[6]; /* ETH_ALEN */
2958 __u8 dmac[6]; /* ETH_ALEN */
2961 enum bpf_task_fd_type {
2962 BPF_FD_TYPE_RAW_TRACEPOINT, /* tp name */
2963 BPF_FD_TYPE_TRACEPOINT, /* tp name */
2964 BPF_FD_TYPE_KPROBE, /* (symbol + offset) or addr */
2965 BPF_FD_TYPE_KRETPROBE, /* (symbol + offset) or addr */
2966 BPF_FD_TYPE_UPROBE, /* filename + offset */
2967 BPF_FD_TYPE_URETPROBE, /* filename + offset */
2970 struct bpf_flow_keys {
2973 __u16 addr_proto; /* ETH_P_* of valid addrs */
2987 __u32 ipv6_src[4]; /* in6_addr; network order */
2988 __u32 ipv6_dst[4]; /* in6_addr; network order */
2993 struct bpf_func_info {
2998 #endif /* _UAPI__LINUX_BPF_H__ */