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_JMP32 0x06 /* jmp mode in word width */
18 #define BPF_ALU64 0x07 /* alu mode in double word width */
21 #define BPF_DW 0x18 /* double word (64-bit) */
22 #define BPF_XADD 0xc0 /* exclusive add */
25 #define BPF_MOV 0xb0 /* mov reg to reg */
26 #define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */
28 /* change endianness of a register */
29 #define BPF_END 0xd0 /* flags for endianness conversion: */
30 #define BPF_TO_LE 0x00 /* convert to little-endian */
31 #define BPF_TO_BE 0x08 /* convert to big-endian */
32 #define BPF_FROM_LE BPF_TO_LE
33 #define BPF_FROM_BE BPF_TO_BE
36 #define BPF_JNE 0x50 /* jump != */
37 #define BPF_JLT 0xa0 /* LT is unsigned, '<' */
38 #define BPF_JLE 0xb0 /* LE is unsigned, '<=' */
39 #define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */
40 #define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */
41 #define BPF_JSLT 0xc0 /* SLT is signed, '<' */
42 #define BPF_JSLE 0xd0 /* SLE is signed, '<=' */
43 #define BPF_CALL 0x80 /* function call */
44 #define BPF_EXIT 0x90 /* function return */
46 /* Register numbers */
62 /* BPF has 10 general purpose 64-bit registers and stack frame. */
63 #define MAX_BPF_REG __MAX_BPF_REG
66 __u8 code; /* opcode */
67 __u8 dst_reg:4; /* dest register */
68 __u8 src_reg:4; /* source register */
69 __s16 off; /* signed offset */
70 __s32 imm; /* signed immediate constant */
73 /* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
74 struct bpf_lpm_trie_key {
75 __u32 prefixlen; /* up to 32 for AF_INET, 128 for AF_INET6 */
76 __u8 data[0]; /* Arbitrary size */
79 struct bpf_cgroup_storage_key {
80 __u64 cgroup_inode_id; /* cgroup inode id */
81 __u32 attach_type; /* program attach type */
84 /* BPF syscall commands, see bpf(2) man-page for details. */
99 BPF_PROG_GET_FD_BY_ID,
100 BPF_MAP_GET_FD_BY_ID,
101 BPF_OBJ_GET_INFO_BY_FD,
103 BPF_RAW_TRACEPOINT_OPEN,
105 BPF_BTF_GET_FD_BY_ID,
107 BPF_MAP_LOOKUP_AND_DELETE_ELEM,
116 BPF_MAP_TYPE_PROG_ARRAY,
117 BPF_MAP_TYPE_PERF_EVENT_ARRAY,
118 BPF_MAP_TYPE_PERCPU_HASH,
119 BPF_MAP_TYPE_PERCPU_ARRAY,
120 BPF_MAP_TYPE_STACK_TRACE,
121 BPF_MAP_TYPE_CGROUP_ARRAY,
122 BPF_MAP_TYPE_LRU_HASH,
123 BPF_MAP_TYPE_LRU_PERCPU_HASH,
124 BPF_MAP_TYPE_LPM_TRIE,
125 BPF_MAP_TYPE_ARRAY_OF_MAPS,
126 BPF_MAP_TYPE_HASH_OF_MAPS,
128 BPF_MAP_TYPE_SOCKMAP,
131 BPF_MAP_TYPE_SOCKHASH,
132 BPF_MAP_TYPE_CGROUP_STORAGE,
133 BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
134 BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
137 BPF_MAP_TYPE_SK_STORAGE,
138 BPF_MAP_TYPE_DEVMAP_HASH,
141 /* Note that tracing related programs such as
142 * BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
143 * are not subject to a stable API since kernel internal data
144 * structures can change from release to release and may
145 * therefore break existing tracing BPF programs. Tracing BPF
146 * programs correspond to /a/ specific kernel which is to be
147 * analyzed, and not /a/ specific kernel /and/ all future ones.
150 BPF_PROG_TYPE_UNSPEC,
151 BPF_PROG_TYPE_SOCKET_FILTER,
152 BPF_PROG_TYPE_KPROBE,
153 BPF_PROG_TYPE_SCHED_CLS,
154 BPF_PROG_TYPE_SCHED_ACT,
155 BPF_PROG_TYPE_TRACEPOINT,
157 BPF_PROG_TYPE_PERF_EVENT,
158 BPF_PROG_TYPE_CGROUP_SKB,
159 BPF_PROG_TYPE_CGROUP_SOCK,
160 BPF_PROG_TYPE_LWT_IN,
161 BPF_PROG_TYPE_LWT_OUT,
162 BPF_PROG_TYPE_LWT_XMIT,
163 BPF_PROG_TYPE_SOCK_OPS,
164 BPF_PROG_TYPE_SK_SKB,
165 BPF_PROG_TYPE_CGROUP_DEVICE,
166 BPF_PROG_TYPE_SK_MSG,
167 BPF_PROG_TYPE_RAW_TRACEPOINT,
168 BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
169 BPF_PROG_TYPE_LWT_SEG6LOCAL,
170 BPF_PROG_TYPE_LIRC_MODE2,
171 BPF_PROG_TYPE_SK_REUSEPORT,
172 BPF_PROG_TYPE_FLOW_DISSECTOR,
173 BPF_PROG_TYPE_CGROUP_SYSCTL,
174 BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
175 BPF_PROG_TYPE_CGROUP_SOCKOPT,
178 enum bpf_attach_type {
179 BPF_CGROUP_INET_INGRESS,
180 BPF_CGROUP_INET_EGRESS,
181 BPF_CGROUP_INET_SOCK_CREATE,
183 BPF_SK_SKB_STREAM_PARSER,
184 BPF_SK_SKB_STREAM_VERDICT,
187 BPF_CGROUP_INET4_BIND,
188 BPF_CGROUP_INET6_BIND,
189 BPF_CGROUP_INET4_CONNECT,
190 BPF_CGROUP_INET6_CONNECT,
191 BPF_CGROUP_INET4_POST_BIND,
192 BPF_CGROUP_INET6_POST_BIND,
193 BPF_CGROUP_UDP4_SENDMSG,
194 BPF_CGROUP_UDP6_SENDMSG,
198 BPF_CGROUP_UDP4_RECVMSG,
199 BPF_CGROUP_UDP6_RECVMSG,
200 BPF_CGROUP_GETSOCKOPT,
201 BPF_CGROUP_SETSOCKOPT,
202 __MAX_BPF_ATTACH_TYPE
205 #define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
207 /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
209 * NONE(default): No further bpf programs allowed in the subtree.
211 * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
212 * the program in this cgroup yields to sub-cgroup program.
214 * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
215 * that cgroup program gets run in addition to the program in this cgroup.
217 * Only one program is allowed to be attached to a cgroup with
218 * NONE or BPF_F_ALLOW_OVERRIDE flag.
219 * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
220 * release old program and attach the new one. Attach flags has to match.
222 * Multiple programs are allowed to be attached to a cgroup with
223 * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
224 * (those that were attached first, run first)
225 * The programs of sub-cgroup are executed first, then programs of
226 * this cgroup and then programs of parent cgroup.
227 * When children program makes decision (like picking TCP CA or sock bind)
228 * parent program has a chance to override it.
230 * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
231 * A cgroup with NONE doesn't allow any programs in sub-cgroups.
233 * cgrp1 (MULTI progs A, B) ->
234 * cgrp2 (OVERRIDE prog C) ->
235 * cgrp3 (MULTI prog D) ->
236 * cgrp4 (OVERRIDE prog E) ->
237 * cgrp5 (NONE prog F)
238 * the event in cgrp5 triggers execution of F,D,A,B in that order.
239 * if prog F is detached, the execution is E,D,A,B
240 * if prog F and D are detached, the execution is E,A,B
241 * if prog F, E and D are detached, the execution is C,A,B
243 * All eligible programs are executed regardless of return code from
246 #define BPF_F_ALLOW_OVERRIDE (1U << 0)
247 #define BPF_F_ALLOW_MULTI (1U << 1)
249 /* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
250 * verifier will perform strict alignment checking as if the kernel
251 * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
252 * and NET_IP_ALIGN defined to 2.
254 #define BPF_F_STRICT_ALIGNMENT (1U << 0)
256 /* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
257 * verifier will allow any alignment whatsoever. On platforms
258 * with strict alignment requirements for loads ands stores (such
259 * as sparc and mips) the verifier validates that all loads and
260 * stores provably follow this requirement. This flag turns that
261 * checking and enforcement off.
263 * It is mostly used for testing when we want to validate the
264 * context and memory access aspects of the verifier, but because
265 * of an unaligned access the alignment check would trigger before
266 * the one we are interested in.
268 #define BPF_F_ANY_ALIGNMENT (1U << 1)
270 /* BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose.
271 * Verifier does sub-register def/use analysis and identifies instructions whose
272 * def only matters for low 32-bit, high 32-bit is never referenced later
273 * through implicit zero extension. Therefore verifier notifies JIT back-ends
274 * that it is safe to ignore clearing high 32-bit for these instructions. This
275 * saves some back-ends a lot of code-gen. However such optimization is not
276 * necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends
277 * hence hasn't used verifier's analysis result. But, we really want to have a
278 * way to be able to verify the correctness of the described optimization on
279 * x86_64 on which testsuites are frequently exercised.
281 * So, this flag is introduced. Once it is set, verifier will randomize high
282 * 32-bit for those instructions who has been identified as safe to ignore them.
283 * Then, if verifier is not doing correct analysis, such randomization will
284 * regress tests to expose bugs.
286 #define BPF_F_TEST_RND_HI32 (1U << 2)
288 /* The verifier internal test flag. Behavior is undefined */
289 #define BPF_F_TEST_STATE_FREQ (1U << 3)
291 /* When BPF ldimm64's insn[0].src_reg != 0 then this can have
294 * insn[0].src_reg: BPF_PSEUDO_MAP_FD BPF_PSEUDO_MAP_VALUE
295 * insn[0].imm: map fd map fd
296 * insn[1].imm: 0 offset into value
299 * ldimm64 rewrite: address of map address of map[0]+offset
300 * verifier type: CONST_PTR_TO_MAP PTR_TO_MAP_VALUE
302 #define BPF_PSEUDO_MAP_FD 1
303 #define BPF_PSEUDO_MAP_VALUE 2
305 /* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
306 * offset to another bpf function
308 #define BPF_PSEUDO_CALL 1
310 /* flags for BPF_MAP_UPDATE_ELEM command */
311 #define BPF_ANY 0 /* create new element or update existing */
312 #define BPF_NOEXIST 1 /* create new element if it didn't exist */
313 #define BPF_EXIST 2 /* update existing element */
314 #define BPF_F_LOCK 4 /* spin_lock-ed map_lookup/map_update */
316 /* flags for BPF_MAP_CREATE command */
317 #define BPF_F_NO_PREALLOC (1U << 0)
318 /* Instead of having one common LRU list in the
319 * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
320 * which can scale and perform better.
321 * Note, the LRU nodes (including free nodes) cannot be moved
322 * across different LRU lists.
324 #define BPF_F_NO_COMMON_LRU (1U << 1)
325 /* Specify numa node during map creation */
326 #define BPF_F_NUMA_NODE (1U << 2)
328 #define BPF_OBJ_NAME_LEN 16U
330 /* Flags for accessing BPF object from syscall side. */
331 #define BPF_F_RDONLY (1U << 3)
332 #define BPF_F_WRONLY (1U << 4)
334 /* Flag for stack_map, store build_id+offset instead of pointer */
335 #define BPF_F_STACK_BUILD_ID (1U << 5)
337 /* Zero-initialize hash function seed. This should only be used for testing. */
338 #define BPF_F_ZERO_SEED (1U << 6)
340 /* Flags for accessing BPF object from program side. */
341 #define BPF_F_RDONLY_PROG (1U << 7)
342 #define BPF_F_WRONLY_PROG (1U << 8)
344 /* Clone map from listener for newly accepted socket */
345 #define BPF_F_CLONE (1U << 9)
347 /* flags for BPF_PROG_QUERY */
348 #define BPF_F_QUERY_EFFECTIVE (1U << 0)
350 enum bpf_stack_build_id_status {
351 /* user space need an empty entry to identify end of a trace */
352 BPF_STACK_BUILD_ID_EMPTY = 0,
353 /* with valid build_id and offset */
354 BPF_STACK_BUILD_ID_VALID = 1,
355 /* couldn't get build_id, fallback to ip */
356 BPF_STACK_BUILD_ID_IP = 2,
359 #define BPF_BUILD_ID_SIZE 20
360 struct bpf_stack_build_id {
362 unsigned char build_id[BPF_BUILD_ID_SIZE];
370 struct { /* anonymous struct used by BPF_MAP_CREATE command */
371 __u32 map_type; /* one of enum bpf_map_type */
372 __u32 key_size; /* size of key in bytes */
373 __u32 value_size; /* size of value in bytes */
374 __u32 max_entries; /* max number of entries in a map */
375 __u32 map_flags; /* BPF_MAP_CREATE related
376 * flags defined above.
378 __u32 inner_map_fd; /* fd pointing to the inner map */
379 __u32 numa_node; /* numa node (effective only if
380 * BPF_F_NUMA_NODE is set).
382 char map_name[BPF_OBJ_NAME_LEN];
383 __u32 map_ifindex; /* ifindex of netdev to create on */
384 __u32 btf_fd; /* fd pointing to a BTF type data */
385 __u32 btf_key_type_id; /* BTF type_id of the key */
386 __u32 btf_value_type_id; /* BTF type_id of the value */
389 struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
394 __aligned_u64 next_key;
399 struct { /* anonymous struct used by BPF_PROG_LOAD command */
400 __u32 prog_type; /* one of enum bpf_prog_type */
403 __aligned_u64 license;
404 __u32 log_level; /* verbosity level of verifier */
405 __u32 log_size; /* size of user buffer */
406 __aligned_u64 log_buf; /* user supplied buffer */
407 __u32 kern_version; /* not used */
409 char prog_name[BPF_OBJ_NAME_LEN];
410 __u32 prog_ifindex; /* ifindex of netdev to prep for */
411 /* For some prog types expected attach type must be known at
412 * load time to verify attach type specific parts of prog
413 * (context accesses, allowed helpers, etc).
415 __u32 expected_attach_type;
416 __u32 prog_btf_fd; /* fd pointing to BTF type data */
417 __u32 func_info_rec_size; /* userspace bpf_func_info size */
418 __aligned_u64 func_info; /* func info */
419 __u32 func_info_cnt; /* number of bpf_func_info records */
420 __u32 line_info_rec_size; /* userspace bpf_line_info size */
421 __aligned_u64 line_info; /* line info */
422 __u32 line_info_cnt; /* number of bpf_line_info records */
423 __u32 attach_btf_id; /* in-kernel BTF type id to attach to */
426 struct { /* anonymous struct used by BPF_OBJ_* commands */
427 __aligned_u64 pathname;
432 struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
433 __u32 target_fd; /* container object to attach to */
434 __u32 attach_bpf_fd; /* eBPF program to attach */
439 struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
442 __u32 data_size_in; /* input: len of data_in */
443 __u32 data_size_out; /* input/output: len of data_out
444 * returns ENOSPC if data_out
447 __aligned_u64 data_in;
448 __aligned_u64 data_out;
451 __u32 ctx_size_in; /* input: len of ctx_in */
452 __u32 ctx_size_out; /* input/output: len of ctx_out
453 * returns ENOSPC if ctx_out
456 __aligned_u64 ctx_in;
457 __aligned_u64 ctx_out;
460 struct { /* anonymous struct used by BPF_*_GET_*_ID */
471 struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
477 struct { /* anonymous struct used by BPF_PROG_QUERY command */
478 __u32 target_fd; /* container object to query */
482 __aligned_u64 prog_ids;
491 struct { /* anonymous struct for BPF_BTF_LOAD */
493 __aligned_u64 btf_log_buf;
500 __u32 pid; /* input: pid */
501 __u32 fd; /* input: fd */
502 __u32 flags; /* input: flags */
503 __u32 buf_len; /* input/output: buf len */
504 __aligned_u64 buf; /* input/output:
505 * tp_name for tracepoint
507 * filename for uprobe
509 __u32 prog_id; /* output: prod_id */
510 __u32 fd_type; /* output: BPF_FD_TYPE_* */
511 __u64 probe_offset; /* output: probe_offset */
512 __u64 probe_addr; /* output: probe_addr */
514 } __attribute__((aligned(8)));
516 /* The description below is an attempt at providing documentation to eBPF
517 * developers about the multiple available eBPF helper functions. It can be
518 * parsed and used to produce a manual page. The workflow is the following,
519 * and requires the rst2man utility:
521 * $ ./scripts/bpf_helpers_doc.py \
522 * --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
523 * $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
524 * $ man /tmp/bpf-helpers.7
526 * Note that in order to produce this external documentation, some RST
527 * formatting is used in the descriptions to get "bold" and "italics" in
528 * manual pages. Also note that the few trailing white spaces are
529 * intentional, removing them would break paragraphs for rst2man.
531 * Start of BPF helper function descriptions:
533 * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
535 * Perform a lookup in *map* for an entry associated to *key*.
537 * Map value associated to *key*, or **NULL** if no entry was
540 * int bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
542 * Add or update the value of the entry associated to *key* in
543 * *map* with *value*. *flags* is one of:
546 * The entry for *key* must not exist in the map.
548 * The entry for *key* must already exist in the map.
550 * No condition on the existence of the entry for *key*.
552 * Flag value **BPF_NOEXIST** cannot be used for maps of types
553 * **BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY** (all
554 * elements always exist), the helper would return an error.
556 * 0 on success, or a negative error in case of failure.
558 * int bpf_map_delete_elem(struct bpf_map *map, const void *key)
560 * Delete entry with *key* from *map*.
562 * 0 on success, or a negative error in case of failure.
564 * int bpf_probe_read(void *dst, u32 size, const void *src)
566 * For tracing programs, safely attempt to read *size* bytes from
567 * address *src* and store the data in *dst*.
569 * 0 on success, or a negative error in case of failure.
571 * u64 bpf_ktime_get_ns(void)
573 * Return the time elapsed since system boot, in nanoseconds.
577 * int bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
579 * This helper is a "printk()-like" facility for debugging. It
580 * prints a message defined by format *fmt* (of size *fmt_size*)
581 * to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
582 * available. It can take up to three additional **u64**
583 * arguments (as an eBPF helpers, the total number of arguments is
586 * Each time the helper is called, it appends a line to the trace.
587 * Lines are discarded while *\/sys/kernel/debug/tracing/trace* is
588 * open, use *\/sys/kernel/debug/tracing/trace_pipe* to avoid this.
589 * The format of the trace is customizable, and the exact output
590 * one will get depends on the options set in
591 * *\/sys/kernel/debug/tracing/trace_options* (see also the
592 * *README* file under the same directory). However, it usually
593 * defaults to something like:
597 * telnet-470 [001] .N.. 419421.045894: 0x00000001: <formatted msg>
601 * * ``telnet`` is the name of the current task.
602 * * ``470`` is the PID of the current task.
603 * * ``001`` is the CPU number on which the task is
605 * * In ``.N..``, each character refers to a set of
606 * options (whether irqs are enabled, scheduling
607 * options, whether hard/softirqs are running, level of
608 * preempt_disabled respectively). **N** means that
609 * **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
611 * * ``419421.045894`` is a timestamp.
612 * * ``0x00000001`` is a fake value used by BPF for the
613 * instruction pointer register.
614 * * ``<formatted msg>`` is the message formatted with
617 * The conversion specifiers supported by *fmt* are similar, but
618 * more limited than for printk(). They are **%d**, **%i**,
619 * **%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
620 * **%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
621 * of field, padding with zeroes, etc.) is available, and the
622 * helper will return **-EINVAL** (but print nothing) if it
623 * encounters an unknown specifier.
625 * Also, note that **bpf_trace_printk**\ () is slow, and should
626 * only be used for debugging purposes. For this reason, a notice
627 * bloc (spanning several lines) is printed to kernel logs and
628 * states that the helper should not be used "for production use"
629 * the first time this helper is used (or more precisely, when
630 * **trace_printk**\ () buffers are allocated). For passing values
631 * to user space, perf events should be preferred.
633 * The number of bytes written to the buffer, or a negative error
634 * in case of failure.
636 * u32 bpf_get_prandom_u32(void)
638 * Get a pseudo-random number.
640 * From a security point of view, this helper uses its own
641 * pseudo-random internal state, and cannot be used to infer the
642 * seed of other random functions in the kernel. However, it is
643 * essential to note that the generator used by the helper is not
644 * cryptographically secure.
646 * A random 32-bit unsigned value.
648 * u32 bpf_get_smp_processor_id(void)
650 * Get the SMP (symmetric multiprocessing) processor id. Note that
651 * all programs run with preemption disabled, which means that the
652 * SMP processor id is stable during all the execution of the
655 * The SMP id of the processor running the program.
657 * int bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
659 * Store *len* bytes from address *from* into the packet
660 * associated to *skb*, at *offset*. *flags* are a combination of
661 * **BPF_F_RECOMPUTE_CSUM** (automatically recompute the
662 * checksum for the packet after storing the bytes) and
663 * **BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
664 * **->swhash** and *skb*\ **->l4hash** to 0).
666 * A call to this helper is susceptible to change the underlying
667 * packet buffer. Therefore, at load time, all checks on pointers
668 * previously done by the verifier are invalidated and must be
669 * performed again, if the helper is used in combination with
670 * direct packet access.
672 * 0 on success, or a negative error in case of failure.
674 * int bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
676 * Recompute the layer 3 (e.g. IP) checksum for the packet
677 * associated to *skb*. Computation is incremental, so the helper
678 * must know the former value of the header field that was
679 * modified (*from*), the new value of this field (*to*), and the
680 * number of bytes (2 or 4) for this field, stored in *size*.
681 * Alternatively, it is possible to store the difference between
682 * the previous and the new values of the header field in *to*, by
683 * setting *from* and *size* to 0. For both methods, *offset*
684 * indicates the location of the IP checksum within the packet.
686 * This helper works in combination with **bpf_csum_diff**\ (),
687 * which does not update the checksum in-place, but offers more
688 * flexibility and can handle sizes larger than 2 or 4 for the
689 * checksum to update.
691 * A call to this helper is susceptible to change the underlying
692 * packet buffer. Therefore, at load time, all checks on pointers
693 * previously done by the verifier are invalidated and must be
694 * performed again, if the helper is used in combination with
695 * direct packet access.
697 * 0 on success, or a negative error in case of failure.
699 * int bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
701 * Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
702 * packet associated to *skb*. Computation is incremental, so the
703 * helper must know the former value of the header field that was
704 * modified (*from*), the new value of this field (*to*), and the
705 * number of bytes (2 or 4) for this field, stored on the lowest
706 * four bits of *flags*. Alternatively, it is possible to store
707 * the difference between the previous and the new values of the
708 * header field in *to*, by setting *from* and the four lowest
709 * bits of *flags* to 0. For both methods, *offset* indicates the
710 * location of the IP checksum within the packet. In addition to
711 * the size of the field, *flags* can be added (bitwise OR) actual
712 * flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
713 * untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
714 * for updates resulting in a null checksum the value is set to
715 * **CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
716 * the checksum is to be computed against a pseudo-header.
718 * This helper works in combination with **bpf_csum_diff**\ (),
719 * which does not update the checksum in-place, but offers more
720 * flexibility and can handle sizes larger than 2 or 4 for the
721 * checksum to update.
723 * A call to this helper is susceptible to change the underlying
724 * packet buffer. Therefore, at load time, all checks on pointers
725 * previously done by the verifier are invalidated and must be
726 * performed again, if the helper is used in combination with
727 * direct packet access.
729 * 0 on success, or a negative error in case of failure.
731 * int bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
733 * This special helper is used to trigger a "tail call", or in
734 * other words, to jump into another eBPF program. The same stack
735 * frame is used (but values on stack and in registers for the
736 * caller are not accessible to the callee). This mechanism allows
737 * for program chaining, either for raising the maximum number of
738 * available eBPF instructions, or to execute given programs in
739 * conditional blocks. For security reasons, there is an upper
740 * limit to the number of successive tail calls that can be
743 * Upon call of this helper, the program attempts to jump into a
744 * program referenced at index *index* in *prog_array_map*, a
745 * special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
746 * *ctx*, a pointer to the context.
748 * If the call succeeds, the kernel immediately runs the first
749 * instruction of the new program. This is not a function call,
750 * and it never returns to the previous program. If the call
751 * fails, then the helper has no effect, and the caller continues
752 * to run its subsequent instructions. A call can fail if the
753 * destination program for the jump does not exist (i.e. *index*
754 * is superior to the number of entries in *prog_array_map*), or
755 * if the maximum number of tail calls has been reached for this
756 * chain of programs. This limit is defined in the kernel by the
757 * macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
758 * which is currently set to 32.
760 * 0 on success, or a negative error in case of failure.
762 * int bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
764 * Clone and redirect the packet associated to *skb* to another
765 * net device of index *ifindex*. Both ingress and egress
766 * interfaces can be used for redirection. The **BPF_F_INGRESS**
767 * value in *flags* is used to make the distinction (ingress path
768 * is selected if the flag is present, egress path otherwise).
769 * This is the only flag supported for now.
771 * In comparison with **bpf_redirect**\ () helper,
772 * **bpf_clone_redirect**\ () has the associated cost of
773 * duplicating the packet buffer, but this can be executed out of
774 * the eBPF program. Conversely, **bpf_redirect**\ () is more
775 * efficient, but it is handled through an action code where the
776 * redirection happens only after the eBPF program has returned.
778 * A call to this helper is susceptible to change the underlying
779 * packet buffer. Therefore, at load time, all checks on pointers
780 * previously done by the verifier are invalidated and must be
781 * performed again, if the helper is used in combination with
782 * direct packet access.
784 * 0 on success, or a negative error in case of failure.
786 * u64 bpf_get_current_pid_tgid(void)
788 * A 64-bit integer containing the current tgid and pid, and
790 * *current_task*\ **->tgid << 32 \|**
791 * *current_task*\ **->pid**.
793 * u64 bpf_get_current_uid_gid(void)
795 * A 64-bit integer containing the current GID and UID, and
796 * created as such: *current_gid* **<< 32 \|** *current_uid*.
798 * int bpf_get_current_comm(void *buf, u32 size_of_buf)
800 * Copy the **comm** attribute of the current task into *buf* of
801 * *size_of_buf*. The **comm** attribute contains the name of
802 * the executable (excluding the path) for the current task. The
803 * *size_of_buf* must be strictly positive. On success, the
804 * helper makes sure that the *buf* is NUL-terminated. On failure,
805 * it is filled with zeroes.
807 * 0 on success, or a negative error in case of failure.
809 * u32 bpf_get_cgroup_classid(struct sk_buff *skb)
811 * Retrieve the classid for the current task, i.e. for the net_cls
812 * cgroup to which *skb* belongs.
814 * This helper can be used on TC egress path, but not on ingress.
816 * The net_cls cgroup provides an interface to tag network packets
817 * based on a user-provided identifier for all traffic coming from
818 * the tasks belonging to the related cgroup. See also the related
819 * kernel documentation, available from the Linux sources in file
820 * *Documentation/admin-guide/cgroup-v1/net_cls.rst*.
822 * The Linux kernel has two versions for cgroups: there are
823 * cgroups v1 and cgroups v2. Both are available to users, who can
824 * use a mixture of them, but note that the net_cls cgroup is for
825 * cgroup v1 only. This makes it incompatible with BPF programs
826 * run on cgroups, which is a cgroup-v2-only feature (a socket can
827 * only hold data for one version of cgroups at a time).
829 * This helper is only available is the kernel was compiled with
830 * the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
831 * "**y**" or to "**m**".
833 * The classid, or 0 for the default unconfigured classid.
835 * int bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
837 * Push a *vlan_tci* (VLAN tag control information) of protocol
838 * *vlan_proto* to the packet associated to *skb*, then update
839 * the checksum. Note that if *vlan_proto* is different from
840 * **ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
841 * be **ETH_P_8021Q**.
843 * A call to this helper is susceptible to change the underlying
844 * packet buffer. Therefore, at load time, all checks on pointers
845 * previously done by the verifier are invalidated and must be
846 * performed again, if the helper is used in combination with
847 * direct packet access.
849 * 0 on success, or a negative error in case of failure.
851 * int bpf_skb_vlan_pop(struct sk_buff *skb)
853 * Pop a VLAN header from the packet associated to *skb*.
855 * A call to this helper is susceptible to change the underlying
856 * packet buffer. Therefore, at load time, all checks on pointers
857 * previously done by the verifier are invalidated and must be
858 * performed again, if the helper is used in combination with
859 * direct packet access.
861 * 0 on success, or a negative error in case of failure.
863 * int bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
865 * Get tunnel metadata. This helper takes a pointer *key* to an
866 * empty **struct bpf_tunnel_key** of **size**, that will be
867 * filled with tunnel metadata for the packet associated to *skb*.
868 * The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
869 * indicates that the tunnel is based on IPv6 protocol instead of
872 * The **struct bpf_tunnel_key** is an object that generalizes the
873 * principal parameters used by various tunneling protocols into a
874 * single struct. This way, it can be used to easily make a
875 * decision based on the contents of the encapsulation header,
876 * "summarized" in this struct. In particular, it holds the IP
877 * address of the remote end (IPv4 or IPv6, depending on the case)
878 * in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
879 * this struct exposes the *key*\ **->tunnel_id**, which is
880 * generally mapped to a VNI (Virtual Network Identifier), making
881 * it programmable together with the **bpf_skb_set_tunnel_key**\
884 * Let's imagine that the following code is part of a program
885 * attached to the TC ingress interface, on one end of a GRE
886 * tunnel, and is supposed to filter out all messages coming from
887 * remote ends with IPv4 address other than 10.0.0.1:
892 * struct bpf_tunnel_key key = {};
894 * ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
896 * return TC_ACT_SHOT; // drop packet
898 * if (key.remote_ipv4 != 0x0a000001)
899 * return TC_ACT_SHOT; // drop packet
901 * return TC_ACT_OK; // accept packet
903 * This interface can also be used with all encapsulation devices
904 * that can operate in "collect metadata" mode: instead of having
905 * one network device per specific configuration, the "collect
906 * metadata" mode only requires a single device where the
907 * configuration can be extracted from this helper.
909 * This can be used together with various tunnels such as VXLan,
910 * Geneve, GRE or IP in IP (IPIP).
912 * 0 on success, or a negative error in case of failure.
914 * int bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
916 * Populate tunnel metadata for packet associated to *skb.* The
917 * tunnel metadata is set to the contents of *key*, of *size*. The
918 * *flags* can be set to a combination of the following values:
920 * **BPF_F_TUNINFO_IPV6**
921 * Indicate that the tunnel is based on IPv6 protocol
923 * **BPF_F_ZERO_CSUM_TX**
924 * For IPv4 packets, add a flag to tunnel metadata
925 * indicating that checksum computation should be skipped
926 * and checksum set to zeroes.
927 * **BPF_F_DONT_FRAGMENT**
928 * Add a flag to tunnel metadata indicating that the
929 * packet should not be fragmented.
930 * **BPF_F_SEQ_NUMBER**
931 * Add a flag to tunnel metadata indicating that a
932 * sequence number should be added to tunnel header before
933 * sending the packet. This flag was added for GRE
934 * encapsulation, but might be used with other protocols
935 * as well in the future.
937 * Here is a typical usage on the transmit path:
941 * struct bpf_tunnel_key key;
943 * bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
944 * bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
946 * See also the description of the **bpf_skb_get_tunnel_key**\ ()
947 * helper for additional information.
949 * 0 on success, or a negative error in case of failure.
951 * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
953 * Read the value of a perf event counter. This helper relies on a
954 * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
955 * the perf event counter is selected when *map* is updated with
956 * perf event file descriptors. The *map* is an array whose size
957 * is the number of available CPUs, and each cell contains a value
958 * relative to one CPU. The value to retrieve is indicated by
959 * *flags*, that contains the index of the CPU to look up, masked
960 * with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
961 * **BPF_F_CURRENT_CPU** to indicate that the value for the
962 * current CPU should be retrieved.
964 * Note that before Linux 4.13, only hardware perf event can be
967 * Also, be aware that the newer helper
968 * **bpf_perf_event_read_value**\ () is recommended over
969 * **bpf_perf_event_read**\ () in general. The latter has some ABI
970 * quirks where error and counter value are used as a return code
971 * (which is wrong to do since ranges may overlap). This issue is
972 * fixed with **bpf_perf_event_read_value**\ (), which at the same
973 * time provides more features over the **bpf_perf_event_read**\
974 * () interface. Please refer to the description of
975 * **bpf_perf_event_read_value**\ () for details.
977 * The value of the perf event counter read from the map, or a
978 * negative error code in case of failure.
980 * int bpf_redirect(u32 ifindex, u64 flags)
982 * Redirect the packet to another net device of index *ifindex*.
983 * This helper is somewhat similar to **bpf_clone_redirect**\
984 * (), except that the packet is not cloned, which provides
985 * increased performance.
987 * Except for XDP, both ingress and egress interfaces can be used
988 * for redirection. The **BPF_F_INGRESS** value in *flags* is used
989 * to make the distinction (ingress path is selected if the flag
990 * is present, egress path otherwise). Currently, XDP only
991 * supports redirection to the egress interface, and accepts no
994 * The same effect can be attained with the more generic
995 * **bpf_redirect_map**\ (), which requires specific maps to be
996 * used but offers better performance.
998 * For XDP, the helper returns **XDP_REDIRECT** on success or
999 * **XDP_ABORTED** on error. For other program types, the values
1000 * are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
1003 * u32 bpf_get_route_realm(struct sk_buff *skb)
1005 * Retrieve the realm or the route, that is to say the
1006 * **tclassid** field of the destination for the *skb*. The
1007 * indentifier retrieved is a user-provided tag, similar to the
1008 * one used with the net_cls cgroup (see description for
1009 * **bpf_get_cgroup_classid**\ () helper), but here this tag is
1010 * held by a route (a destination entry), not by a task.
1012 * Retrieving this identifier works with the clsact TC egress hook
1013 * (see also **tc-bpf(8)**), or alternatively on conventional
1014 * classful egress qdiscs, but not on TC ingress path. In case of
1015 * clsact TC egress hook, this has the advantage that, internally,
1016 * the destination entry has not been dropped yet in the transmit
1017 * path. Therefore, the destination entry does not need to be
1018 * artificially held via **netif_keep_dst**\ () for a classful
1019 * qdisc until the *skb* is freed.
1021 * This helper is available only if the kernel was compiled with
1022 * **CONFIG_IP_ROUTE_CLASSID** configuration option.
1024 * The realm of the route for the packet associated to *skb*, or 0
1025 * if none was found.
1027 * int bpf_perf_event_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
1029 * Write raw *data* blob into a special BPF perf event held by
1030 * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
1031 * event must have the following attributes: **PERF_SAMPLE_RAW**
1032 * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
1033 * **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
1035 * The *flags* are used to indicate the index in *map* for which
1036 * the value must be put, masked with **BPF_F_INDEX_MASK**.
1037 * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
1038 * to indicate that the index of the current CPU core should be
1041 * The value to write, of *size*, is passed through eBPF stack and
1042 * pointed by *data*.
1044 * The context of the program *ctx* needs also be passed to the
1047 * On user space, a program willing to read the values needs to
1048 * call **perf_event_open**\ () on the perf event (either for
1049 * one or for all CPUs) and to store the file descriptor into the
1050 * *map*. This must be done before the eBPF program can send data
1051 * into it. An example is available in file
1052 * *samples/bpf/trace_output_user.c* in the Linux kernel source
1053 * tree (the eBPF program counterpart is in
1054 * *samples/bpf/trace_output_kern.c*).
1056 * **bpf_perf_event_output**\ () achieves better performance
1057 * than **bpf_trace_printk**\ () for sharing data with user
1058 * space, and is much better suitable for streaming data from eBPF
1061 * Note that this helper is not restricted to tracing use cases
1062 * and can be used with programs attached to TC or XDP as well,
1063 * where it allows for passing data to user space listeners. Data
1066 * * Only custom structs,
1067 * * Only the packet payload, or
1068 * * A combination of both.
1070 * 0 on success, or a negative error in case of failure.
1072 * int bpf_skb_load_bytes(const void *skb, u32 offset, void *to, u32 len)
1074 * This helper was provided as an easy way to load data from a
1075 * packet. It can be used to load *len* bytes from *offset* from
1076 * the packet associated to *skb*, into the buffer pointed by
1079 * Since Linux 4.7, usage of this helper has mostly been replaced
1080 * by "direct packet access", enabling packet data to be
1081 * manipulated with *skb*\ **->data** and *skb*\ **->data_end**
1082 * pointing respectively to the first byte of packet data and to
1083 * the byte after the last byte of packet data. However, it
1084 * remains useful if one wishes to read large quantities of data
1085 * at once from a packet into the eBPF stack.
1087 * 0 on success, or a negative error in case of failure.
1089 * int bpf_get_stackid(void *ctx, struct bpf_map *map, u64 flags)
1091 * Walk a user or a kernel stack and return its id. To achieve
1092 * this, the helper needs *ctx*, which is a pointer to the context
1093 * on which the tracing program is executed, and a pointer to a
1094 * *map* of type **BPF_MAP_TYPE_STACK_TRACE**.
1096 * The last argument, *flags*, holds the number of stack frames to
1097 * skip (from 0 to 255), masked with
1098 * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
1099 * a combination of the following flags:
1101 * **BPF_F_USER_STACK**
1102 * Collect a user space stack instead of a kernel stack.
1103 * **BPF_F_FAST_STACK_CMP**
1104 * Compare stacks by hash only.
1105 * **BPF_F_REUSE_STACKID**
1106 * If two different stacks hash into the same *stackid*,
1107 * discard the old one.
1109 * The stack id retrieved is a 32 bit long integer handle which
1110 * can be further combined with other data (including other stack
1111 * ids) and used as a key into maps. This can be useful for
1112 * generating a variety of graphs (such as flame graphs or off-cpu
1115 * For walking a stack, this helper is an improvement over
1116 * **bpf_probe_read**\ (), which can be used with unrolled loops
1117 * but is not efficient and consumes a lot of eBPF instructions.
1118 * Instead, **bpf_get_stackid**\ () can collect up to
1119 * **PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
1120 * this limit can be controlled with the **sysctl** program, and
1121 * that it should be manually increased in order to profile long
1122 * user stacks (such as stacks for Java programs). To do so, use:
1126 * # sysctl kernel.perf_event_max_stack=<new value>
1128 * The positive or null stack id on success, or a negative error
1129 * in case of failure.
1131 * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
1133 * Compute a checksum difference, from the raw buffer pointed by
1134 * *from*, of length *from_size* (that must be a multiple of 4),
1135 * towards the raw buffer pointed by *to*, of size *to_size*
1136 * (same remark). An optional *seed* can be added to the value
1137 * (this can be cascaded, the seed may come from a previous call
1140 * This is flexible enough to be used in several ways:
1142 * * With *from_size* == 0, *to_size* > 0 and *seed* set to
1143 * checksum, it can be used when pushing new data.
1144 * * With *from_size* > 0, *to_size* == 0 and *seed* set to
1145 * checksum, it can be used when removing data from a packet.
1146 * * With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
1147 * can be used to compute a diff. Note that *from_size* and
1148 * *to_size* do not need to be equal.
1150 * This helper can be used in combination with
1151 * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
1152 * which one can feed in the difference computed with
1153 * **bpf_csum_diff**\ ().
1155 * The checksum result, or a negative error code in case of
1158 * int bpf_skb_get_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
1160 * Retrieve tunnel options metadata for the packet associated to
1161 * *skb*, and store the raw tunnel option data to the buffer *opt*
1164 * This helper can be used with encapsulation devices that can
1165 * operate in "collect metadata" mode (please refer to the related
1166 * note in the description of **bpf_skb_get_tunnel_key**\ () for
1167 * more details). A particular example where this can be used is
1168 * in combination with the Geneve encapsulation protocol, where it
1169 * allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
1170 * and retrieving arbitrary TLVs (Type-Length-Value headers) from
1171 * the eBPF program. This allows for full customization of these
1174 * The size of the option data retrieved.
1176 * int bpf_skb_set_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
1178 * Set tunnel options metadata for the packet associated to *skb*
1179 * to the option data contained in the raw buffer *opt* of *size*.
1181 * See also the description of the **bpf_skb_get_tunnel_opt**\ ()
1182 * helper for additional information.
1184 * 0 on success, or a negative error in case of failure.
1186 * int bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
1188 * Change the protocol of the *skb* to *proto*. Currently
1189 * supported are transition from IPv4 to IPv6, and from IPv6 to
1190 * IPv4. The helper takes care of the groundwork for the
1191 * transition, including resizing the socket buffer. The eBPF
1192 * program is expected to fill the new headers, if any, via
1193 * **skb_store_bytes**\ () and to recompute the checksums with
1194 * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
1195 * (). The main case for this helper is to perform NAT64
1196 * operations out of an eBPF program.
1198 * Internally, the GSO type is marked as dodgy so that headers are
1199 * checked and segments are recalculated by the GSO/GRO engine.
1200 * The size for GSO target is adapted as well.
1202 * All values for *flags* are reserved for future usage, and must
1205 * A call to this helper is susceptible to change the underlying
1206 * packet buffer. Therefore, at load time, all checks on pointers
1207 * previously done by the verifier are invalidated and must be
1208 * performed again, if the helper is used in combination with
1209 * direct packet access.
1211 * 0 on success, or a negative error in case of failure.
1213 * int bpf_skb_change_type(struct sk_buff *skb, u32 type)
1215 * Change the packet type for the packet associated to *skb*. This
1216 * comes down to setting *skb*\ **->pkt_type** to *type*, except
1217 * the eBPF program does not have a write access to *skb*\
1218 * **->pkt_type** beside this helper. Using a helper here allows
1219 * for graceful handling of errors.
1221 * The major use case is to change incoming *skb*s to
1222 * **PACKET_HOST** in a programmatic way instead of having to
1223 * recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
1226 * Note that *type* only allows certain values. At this time, they
1231 * **PACKET_BROADCAST**
1232 * Send packet to all.
1233 * **PACKET_MULTICAST**
1234 * Send packet to group.
1235 * **PACKET_OTHERHOST**
1236 * Send packet to someone else.
1238 * 0 on success, or a negative error in case of failure.
1240 * int bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
1242 * Check whether *skb* is a descendant of the cgroup2 held by
1243 * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
1245 * The return value depends on the result of the test, and can be:
1247 * * 0, if the *skb* failed the cgroup2 descendant test.
1248 * * 1, if the *skb* succeeded the cgroup2 descendant test.
1249 * * A negative error code, if an error occurred.
1251 * u32 bpf_get_hash_recalc(struct sk_buff *skb)
1253 * Retrieve the hash of the packet, *skb*\ **->hash**. If it is
1254 * not set, in particular if the hash was cleared due to mangling,
1255 * recompute this hash. Later accesses to the hash can be done
1256 * directly with *skb*\ **->hash**.
1258 * Calling **bpf_set_hash_invalid**\ (), changing a packet
1259 * prototype with **bpf_skb_change_proto**\ (), or calling
1260 * **bpf_skb_store_bytes**\ () with the
1261 * **BPF_F_INVALIDATE_HASH** are actions susceptible to clear
1262 * the hash and to trigger a new computation for the next call to
1263 * **bpf_get_hash_recalc**\ ().
1267 * u64 bpf_get_current_task(void)
1269 * A pointer to the current task struct.
1271 * int bpf_probe_write_user(void *dst, const void *src, u32 len)
1273 * Attempt in a safe way to write *len* bytes from the buffer
1274 * *src* to *dst* in memory. It only works for threads that are in
1275 * user context, and *dst* must be a valid user space address.
1277 * This helper should not be used to implement any kind of
1278 * security mechanism because of TOC-TOU attacks, but rather to
1279 * debug, divert, and manipulate execution of semi-cooperative
1282 * Keep in mind that this feature is meant for experiments, and it
1283 * has a risk of crashing the system and running programs.
1284 * Therefore, when an eBPF program using this helper is attached,
1285 * a warning including PID and process name is printed to kernel
1288 * 0 on success, or a negative error in case of failure.
1290 * int bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
1292 * Check whether the probe is being run is the context of a given
1293 * subset of the cgroup2 hierarchy. The cgroup2 to test is held by
1294 * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
1296 * The return value depends on the result of the test, and can be:
1298 * * 0, if the *skb* task belongs to the cgroup2.
1299 * * 1, if the *skb* task does not belong to the cgroup2.
1300 * * A negative error code, if an error occurred.
1302 * int bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
1304 * Resize (trim or grow) the packet associated to *skb* to the
1305 * new *len*. The *flags* are reserved for future usage, and must
1308 * The basic idea is that the helper performs the needed work to
1309 * change the size of the packet, then the eBPF program rewrites
1310 * the rest via helpers like **bpf_skb_store_bytes**\ (),
1311 * **bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
1312 * and others. This helper is a slow path utility intended for
1313 * replies with control messages. And because it is targeted for
1314 * slow path, the helper itself can afford to be slow: it
1315 * implicitly linearizes, unclones and drops offloads from the
1318 * A call to this helper is susceptible to change the underlying
1319 * packet buffer. Therefore, at load time, all checks on pointers
1320 * previously done by the verifier are invalidated and must be
1321 * performed again, if the helper is used in combination with
1322 * direct packet access.
1324 * 0 on success, or a negative error in case of failure.
1326 * int bpf_skb_pull_data(struct sk_buff *skb, u32 len)
1328 * Pull in non-linear data in case the *skb* is non-linear and not
1329 * all of *len* are part of the linear section. Make *len* bytes
1330 * from *skb* readable and writable. If a zero value is passed for
1331 * *len*, then the whole length of the *skb* is pulled.
1333 * This helper is only needed for reading and writing with direct
1336 * For direct packet access, testing that offsets to access
1337 * are within packet boundaries (test on *skb*\ **->data_end**) is
1338 * susceptible to fail if offsets are invalid, or if the requested
1339 * data is in non-linear parts of the *skb*. On failure the
1340 * program can just bail out, or in the case of a non-linear
1341 * buffer, use a helper to make the data available. The
1342 * **bpf_skb_load_bytes**\ () helper is a first solution to access
1343 * the data. Another one consists in using **bpf_skb_pull_data**
1344 * to pull in once the non-linear parts, then retesting and
1345 * eventually access the data.
1347 * At the same time, this also makes sure the *skb* is uncloned,
1348 * which is a necessary condition for direct write. As this needs
1349 * to be an invariant for the write part only, the verifier
1350 * detects writes and adds a prologue that is calling
1351 * **bpf_skb_pull_data()** to effectively unclone the *skb* from
1352 * the very beginning in case it is indeed cloned.
1354 * A call to this helper is susceptible to change the underlying
1355 * packet buffer. Therefore, at load time, all checks on pointers
1356 * previously done by the verifier are invalidated and must be
1357 * performed again, if the helper is used in combination with
1358 * direct packet access.
1360 * 0 on success, or a negative error in case of failure.
1362 * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
1364 * Add the checksum *csum* into *skb*\ **->csum** in case the
1365 * driver has supplied a checksum for the entire packet into that
1366 * field. Return an error otherwise. This helper is intended to be
1367 * used in combination with **bpf_csum_diff**\ (), in particular
1368 * when the checksum needs to be updated after data has been
1369 * written into the packet through direct packet access.
1371 * The checksum on success, or a negative error code in case of
1374 * void bpf_set_hash_invalid(struct sk_buff *skb)
1376 * Invalidate the current *skb*\ **->hash**. It can be used after
1377 * mangling on headers through direct packet access, in order to
1378 * indicate that the hash is outdated and to trigger a
1379 * recalculation the next time the kernel tries to access this
1380 * hash or when the **bpf_get_hash_recalc**\ () helper is called.
1382 * int bpf_get_numa_node_id(void)
1384 * Return the id of the current NUMA node. The primary use case
1385 * for this helper is the selection of sockets for the local NUMA
1386 * node, when the program is attached to sockets using the
1387 * **SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
1388 * but the helper is also available to other eBPF program types,
1389 * similarly to **bpf_get_smp_processor_id**\ ().
1391 * The id of current NUMA node.
1393 * int bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
1395 * Grows headroom of packet associated to *skb* and adjusts the
1396 * offset of the MAC header accordingly, adding *len* bytes of
1397 * space. It automatically extends and reallocates memory as
1400 * This helper can be used on a layer 3 *skb* to push a MAC header
1401 * for redirection into a layer 2 device.
1403 * All values for *flags* are reserved for future usage, and must
1406 * A call to this helper is susceptible to change the underlying
1407 * packet buffer. Therefore, at load time, all checks on pointers
1408 * previously done by the verifier are invalidated and must be
1409 * performed again, if the helper is used in combination with
1410 * direct packet access.
1412 * 0 on success, or a negative error in case of failure.
1414 * int bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
1416 * Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
1417 * it is possible to use a negative value for *delta*. This helper
1418 * can be used to prepare the packet for pushing or popping
1421 * A call to this helper is susceptible to change the underlying
1422 * packet buffer. Therefore, at load time, all checks on pointers
1423 * previously done by the verifier are invalidated and must be
1424 * performed again, if the helper is used in combination with
1425 * direct packet access.
1427 * 0 on success, or a negative error in case of failure.
1429 * int bpf_probe_read_str(void *dst, int size, const void *unsafe_ptr)
1431 * Copy a NUL terminated string from an unsafe address
1432 * *unsafe_ptr* to *dst*. The *size* should include the
1433 * terminating NUL byte. In case the string length is smaller than
1434 * *size*, the target is not padded with further NUL bytes. If the
1435 * string length is larger than *size*, just *size*-1 bytes are
1436 * copied and the last byte is set to NUL.
1438 * On success, the length of the copied string is returned. This
1439 * makes this helper useful in tracing programs for reading
1440 * strings, and more importantly to get its length at runtime. See
1441 * the following snippet:
1445 * SEC("kprobe/sys_open")
1446 * void bpf_sys_open(struct pt_regs *ctx)
1448 * char buf[PATHLEN]; // PATHLEN is defined to 256
1449 * int res = bpf_probe_read_str(buf, sizeof(buf),
1452 * // Consume buf, for example push it to
1453 * // userspace via bpf_perf_event_output(); we
1454 * // can use res (the string length) as event
1455 * // size, after checking its boundaries.
1458 * In comparison, using **bpf_probe_read()** helper here instead
1459 * to read the string would require to estimate the length at
1460 * compile time, and would often result in copying more memory
1463 * Another useful use case is when parsing individual process
1464 * arguments or individual environment variables navigating
1465 * *current*\ **->mm->arg_start** and *current*\
1466 * **->mm->env_start**: using this helper and the return value,
1467 * one can quickly iterate at the right offset of the memory area.
1469 * On success, the strictly positive length of the string,
1470 * including the trailing NUL character. On error, a negative
1473 * u64 bpf_get_socket_cookie(struct sk_buff *skb)
1475 * If the **struct sk_buff** pointed by *skb* has a known socket,
1476 * retrieve the cookie (generated by the kernel) of this socket.
1477 * If no cookie has been set yet, generate a new cookie. Once
1478 * generated, the socket cookie remains stable for the life of the
1479 * socket. This helper can be useful for monitoring per socket
1480 * networking traffic statistics as it provides a global socket
1481 * identifier that can be assumed unique.
1483 * A 8-byte long non-decreasing number on success, or 0 if the
1484 * socket field is missing inside *skb*.
1486 * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
1488 * Equivalent to bpf_get_socket_cookie() helper that accepts
1489 * *skb*, but gets socket from **struct bpf_sock_addr** context.
1491 * A 8-byte long non-decreasing number.
1493 * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
1495 * Equivalent to bpf_get_socket_cookie() helper that accepts
1496 * *skb*, but gets socket from **struct bpf_sock_ops** context.
1498 * A 8-byte long non-decreasing number.
1500 * u32 bpf_get_socket_uid(struct sk_buff *skb)
1502 * The owner UID of the socket associated to *skb*. If the socket
1503 * is **NULL**, or if it is not a full socket (i.e. if it is a
1504 * time-wait or a request socket instead), **overflowuid** value
1505 * is returned (note that **overflowuid** might also be the actual
1506 * UID value for the socket).
1508 * u32 bpf_set_hash(struct sk_buff *skb, u32 hash)
1510 * Set the full hash for *skb* (set the field *skb*\ **->hash**)
1515 * int bpf_setsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, void *optval, int optlen)
1517 * Emulate a call to **setsockopt()** on the socket associated to
1518 * *bpf_socket*, which must be a full socket. The *level* at
1519 * which the option resides and the name *optname* of the option
1520 * must be specified, see **setsockopt(2)** for more information.
1521 * The option value of length *optlen* is pointed by *optval*.
1523 * This helper actually implements a subset of **setsockopt()**.
1524 * It supports the following *level*\ s:
1526 * * **SOL_SOCKET**, which supports the following *optname*\ s:
1527 * **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
1528 * **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**.
1529 * * **IPPROTO_TCP**, which supports the following *optname*\ s:
1530 * **TCP_CONGESTION**, **TCP_BPF_IW**,
1531 * **TCP_BPF_SNDCWND_CLAMP**.
1532 * * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
1533 * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
1535 * 0 on success, or a negative error in case of failure.
1537 * int bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
1539 * Grow or shrink the room for data in the packet associated to
1540 * *skb* by *len_diff*, and according to the selected *mode*.
1542 * There are two supported modes at this time:
1544 * * **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
1545 * (room space is added or removed below the layer 2 header).
1547 * * **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
1548 * (room space is added or removed below the layer 3 header).
1550 * The following flags are supported at this time:
1552 * * **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
1553 * Adjusting mss in this way is not allowed for datagrams.
1555 * * **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**,
1556 * **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**:
1557 * Any new space is reserved to hold a tunnel header.
1558 * Configure skb offsets and other fields accordingly.
1560 * * **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**,
1561 * **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**:
1562 * Use with ENCAP_L3 flags to further specify the tunnel type.
1564 * * **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*):
1565 * Use with ENCAP_L3/L4 flags to further specify the tunnel
1566 * type; *len* is the length of the inner MAC header.
1568 * A call to this helper is susceptible to change the underlying
1569 * packet buffer. Therefore, at load time, all checks on pointers
1570 * previously done by the verifier are invalidated and must be
1571 * performed again, if the helper is used in combination with
1572 * direct packet access.
1574 * 0 on success, or a negative error in case of failure.
1576 * int bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
1578 * Redirect the packet to the endpoint referenced by *map* at
1579 * index *key*. Depending on its type, this *map* can contain
1580 * references to net devices (for forwarding packets through other
1581 * ports), or to CPUs (for redirecting XDP frames to another CPU;
1582 * but this is only implemented for native XDP (with driver
1583 * support) as of this writing).
1585 * The lower two bits of *flags* are used as the return code if
1586 * the map lookup fails. This is so that the return value can be
1587 * one of the XDP program return codes up to XDP_TX, as chosen by
1588 * the caller. Any higher bits in the *flags* argument must be
1591 * When used to redirect packets to net devices, this helper
1592 * provides a high performance increase over **bpf_redirect**\ ().
1593 * This is due to various implementation details of the underlying
1594 * mechanisms, one of which is the fact that **bpf_redirect_map**\
1595 * () tries to send packet as a "bulk" to the device.
1597 * **XDP_REDIRECT** on success, or **XDP_ABORTED** on error.
1599 * int bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
1601 * Redirect the packet to the socket referenced by *map* (of type
1602 * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
1603 * egress interfaces can be used for redirection. The
1604 * **BPF_F_INGRESS** value in *flags* is used to make the
1605 * distinction (ingress path is selected if the flag is present,
1606 * egress path otherwise). This is the only flag supported for now.
1608 * **SK_PASS** on success, or **SK_DROP** on error.
1610 * int bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
1612 * Add an entry to, or update a *map* referencing sockets. The
1613 * *skops* is used as a new value for the entry associated to
1614 * *key*. *flags* is one of:
1617 * The entry for *key* must not exist in the map.
1619 * The entry for *key* must already exist in the map.
1621 * No condition on the existence of the entry for *key*.
1623 * If the *map* has eBPF programs (parser and verdict), those will
1624 * be inherited by the socket being added. If the socket is
1625 * already attached to eBPF programs, this results in an error.
1627 * 0 on success, or a negative error in case of failure.
1629 * int bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
1631 * Adjust the address pointed by *xdp_md*\ **->data_meta** by
1632 * *delta* (which can be positive or negative). Note that this
1633 * operation modifies the address stored in *xdp_md*\ **->data**,
1634 * so the latter must be loaded only after the helper has been
1637 * The use of *xdp_md*\ **->data_meta** is optional and programs
1638 * are not required to use it. The rationale is that when the
1639 * packet is processed with XDP (e.g. as DoS filter), it is
1640 * possible to push further meta data along with it before passing
1641 * to the stack, and to give the guarantee that an ingress eBPF
1642 * program attached as a TC classifier on the same device can pick
1643 * this up for further post-processing. Since TC works with socket
1644 * buffers, it remains possible to set from XDP the **mark** or
1645 * **priority** pointers, or other pointers for the socket buffer.
1646 * Having this scratch space generic and programmable allows for
1647 * more flexibility as the user is free to store whatever meta
1650 * A call to this helper is susceptible to change the underlying
1651 * packet buffer. Therefore, at load time, all checks on pointers
1652 * previously done by the verifier are invalidated and must be
1653 * performed again, if the helper is used in combination with
1654 * direct packet access.
1656 * 0 on success, or a negative error in case of failure.
1658 * int bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
1660 * Read the value of a perf event counter, and store it into *buf*
1661 * of size *buf_size*. This helper relies on a *map* of type
1662 * **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
1663 * counter is selected when *map* is updated with perf event file
1664 * descriptors. The *map* is an array whose size is the number of
1665 * available CPUs, and each cell contains a value relative to one
1666 * CPU. The value to retrieve is indicated by *flags*, that
1667 * contains the index of the CPU to look up, masked with
1668 * **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
1669 * **BPF_F_CURRENT_CPU** to indicate that the value for the
1670 * current CPU should be retrieved.
1672 * This helper behaves in a way close to
1673 * **bpf_perf_event_read**\ () helper, save that instead of
1674 * just returning the value observed, it fills the *buf*
1675 * structure. This allows for additional data to be retrieved: in
1676 * particular, the enabled and running times (in *buf*\
1677 * **->enabled** and *buf*\ **->running**, respectively) are
1678 * copied. In general, **bpf_perf_event_read_value**\ () is
1679 * recommended over **bpf_perf_event_read**\ (), which has some
1680 * ABI issues and provides fewer functionalities.
1682 * These values are interesting, because hardware PMU (Performance
1683 * Monitoring Unit) counters are limited resources. When there are
1684 * more PMU based perf events opened than available counters,
1685 * kernel will multiplex these events so each event gets certain
1686 * percentage (but not all) of the PMU time. In case that
1687 * multiplexing happens, the number of samples or counter value
1688 * will not reflect the case compared to when no multiplexing
1689 * occurs. This makes comparison between different runs difficult.
1690 * Typically, the counter value should be normalized before
1691 * comparing to other experiments. The usual normalization is done
1696 * normalized_counter = counter * t_enabled / t_running
1698 * Where t_enabled is the time enabled for event and t_running is
1699 * the time running for event since last normalization. The
1700 * enabled and running times are accumulated since the perf event
1701 * open. To achieve scaling factor between two invocations of an
1702 * eBPF program, users can can use CPU id as the key (which is
1703 * typical for perf array usage model) to remember the previous
1704 * value and do the calculation inside the eBPF program.
1706 * 0 on success, or a negative error in case of failure.
1708 * int bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
1710 * For en eBPF program attached to a perf event, retrieve the
1711 * value of the event counter associated to *ctx* and store it in
1712 * the structure pointed by *buf* and of size *buf_size*. Enabled
1713 * and running times are also stored in the structure (see
1714 * description of helper **bpf_perf_event_read_value**\ () for
1717 * 0 on success, or a negative error in case of failure.
1719 * int bpf_getsockopt(struct bpf_sock_ops *bpf_socket, int level, int optname, void *optval, int optlen)
1721 * Emulate a call to **getsockopt()** on the socket associated to
1722 * *bpf_socket*, which must be a full socket. The *level* at
1723 * which the option resides and the name *optname* of the option
1724 * must be specified, see **getsockopt(2)** for more information.
1725 * The retrieved value is stored in the structure pointed by
1726 * *opval* and of length *optlen*.
1728 * This helper actually implements a subset of **getsockopt()**.
1729 * It supports the following *level*\ s:
1731 * * **IPPROTO_TCP**, which supports *optname*
1732 * **TCP_CONGESTION**.
1733 * * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
1734 * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
1736 * 0 on success, or a negative error in case of failure.
1738 * int bpf_override_return(struct pt_regs *regs, u64 rc)
1740 * Used for error injection, this helper uses kprobes to override
1741 * the return value of the probed function, and to set it to *rc*.
1742 * The first argument is the context *regs* on which the kprobe
1745 * This helper works by setting setting the PC (program counter)
1746 * to an override function which is run in place of the original
1747 * probed function. This means the probed function is not run at
1748 * all. The replacement function just returns with the required
1751 * This helper has security implications, and thus is subject to
1752 * restrictions. It is only available if the kernel was compiled
1753 * with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
1754 * option, and in this case it only works on functions tagged with
1755 * **ALLOW_ERROR_INJECTION** in the kernel code.
1757 * Also, the helper is only available for the architectures having
1758 * the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
1759 * x86 architecture is the only one to support this feature.
1763 * int bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
1765 * Attempt to set the value of the **bpf_sock_ops_cb_flags** field
1766 * for the full TCP socket associated to *bpf_sock_ops* to
1769 * The primary use of this field is to determine if there should
1770 * be calls to eBPF programs of type
1771 * **BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
1772 * code. A program of the same type can change its value, per
1773 * connection and as necessary, when the connection is
1774 * established. This field is directly accessible for reading, but
1775 * this helper must be used for updates in order to return an
1776 * error if an eBPF program tries to set a callback that is not
1777 * supported in the current kernel.
1779 * *argval* is a flag array which can combine these flags:
1781 * * **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
1782 * * **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
1783 * * **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
1784 * * **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT)
1786 * Therefore, this function can be used to clear a callback flag by
1787 * setting the appropriate bit to zero. e.g. to disable the RTO
1790 * **bpf_sock_ops_cb_flags_set(bpf_sock,**
1791 * **bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)**
1793 * Here are some examples of where one could call such eBPF
1797 * * When a packet is retransmitted.
1798 * * When the connection terminates.
1799 * * When a packet is sent.
1800 * * When a packet is received.
1802 * Code **-EINVAL** if the socket is not a full TCP socket;
1803 * otherwise, a positive number containing the bits that could not
1804 * be set is returned (which comes down to 0 if all bits were set
1807 * int bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
1809 * This helper is used in programs implementing policies at the
1810 * socket level. If the message *msg* is allowed to pass (i.e. if
1811 * the verdict eBPF program returns **SK_PASS**), redirect it to
1812 * the socket referenced by *map* (of type
1813 * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
1814 * egress interfaces can be used for redirection. The
1815 * **BPF_F_INGRESS** value in *flags* is used to make the
1816 * distinction (ingress path is selected if the flag is present,
1817 * egress path otherwise). This is the only flag supported for now.
1819 * **SK_PASS** on success, or **SK_DROP** on error.
1821 * int bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
1823 * For socket policies, apply the verdict of the eBPF program to
1824 * the next *bytes* (number of bytes) of message *msg*.
1826 * For example, this helper can be used in the following cases:
1828 * * A single **sendmsg**\ () or **sendfile**\ () system call
1829 * contains multiple logical messages that the eBPF program is
1830 * supposed to read and for which it should apply a verdict.
1831 * * An eBPF program only cares to read the first *bytes* of a
1832 * *msg*. If the message has a large payload, then setting up
1833 * and calling the eBPF program repeatedly for all bytes, even
1834 * though the verdict is already known, would create unnecessary
1837 * When called from within an eBPF program, the helper sets a
1838 * counter internal to the BPF infrastructure, that is used to
1839 * apply the last verdict to the next *bytes*. If *bytes* is
1840 * smaller than the current data being processed from a
1841 * **sendmsg**\ () or **sendfile**\ () system call, the first
1842 * *bytes* will be sent and the eBPF program will be re-run with
1843 * the pointer for start of data pointing to byte number *bytes*
1844 * **+ 1**. If *bytes* is larger than the current data being
1845 * processed, then the eBPF verdict will be applied to multiple
1846 * **sendmsg**\ () or **sendfile**\ () calls until *bytes* are
1849 * Note that if a socket closes with the internal counter holding
1850 * a non-zero value, this is not a problem because data is not
1851 * being buffered for *bytes* and is sent as it is received.
1855 * int bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
1857 * For socket policies, prevent the execution of the verdict eBPF
1858 * program for message *msg* until *bytes* (byte number) have been
1861 * This can be used when one needs a specific number of bytes
1862 * before a verdict can be assigned, even if the data spans
1863 * multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
1864 * case would be a user calling **sendmsg**\ () repeatedly with
1865 * 1-byte long message segments. Obviously, this is bad for
1866 * performance, but it is still valid. If the eBPF program needs
1867 * *bytes* bytes to validate a header, this helper can be used to
1868 * prevent the eBPF program to be called again until *bytes* have
1873 * int bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
1875 * For socket policies, pull in non-linear data from user space
1876 * for *msg* and set pointers *msg*\ **->data** and *msg*\
1877 * **->data_end** to *start* and *end* bytes offsets into *msg*,
1880 * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
1881 * *msg* it can only parse data that the (**data**, **data_end**)
1882 * pointers have already consumed. For **sendmsg**\ () hooks this
1883 * is likely the first scatterlist element. But for calls relying
1884 * on the **sendpage** handler (e.g. **sendfile**\ ()) this will
1885 * be the range (**0**, **0**) because the data is shared with
1886 * user space and by default the objective is to avoid allowing
1887 * user space to modify data while (or after) eBPF verdict is
1888 * being decided. This helper can be used to pull in data and to
1889 * set the start and end pointer to given values. Data will be
1890 * copied if necessary (i.e. if data was not linear and if start
1891 * and end pointers do not point to the same chunk).
1893 * A call to this helper is susceptible to change the underlying
1894 * packet buffer. Therefore, at load time, all checks on pointers
1895 * previously done by the verifier are invalidated and must be
1896 * performed again, if the helper is used in combination with
1897 * direct packet access.
1899 * All values for *flags* are reserved for future usage, and must
1902 * 0 on success, or a negative error in case of failure.
1904 * int bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
1906 * Bind the socket associated to *ctx* to the address pointed by
1907 * *addr*, of length *addr_len*. This allows for making outgoing
1908 * connection from the desired IP address, which can be useful for
1909 * example when all processes inside a cgroup should use one
1910 * single IP address on a host that has multiple IP configured.
1912 * This helper works for IPv4 and IPv6, TCP and UDP sockets. The
1913 * domain (*addr*\ **->sa_family**) must be **AF_INET** (or
1914 * **AF_INET6**). Looking for a free port to bind to can be
1915 * expensive, therefore binding to port is not permitted by the
1916 * helper: *addr*\ **->sin_port** (or **sin6_port**, respectively)
1917 * must be set to zero.
1919 * 0 on success, or a negative error in case of failure.
1921 * int bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
1923 * Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
1924 * only possible to shrink the packet as of this writing,
1925 * therefore *delta* must be a negative integer.
1927 * A call to this helper is susceptible to change the underlying
1928 * packet buffer. Therefore, at load time, all checks on pointers
1929 * previously done by the verifier are invalidated and must be
1930 * performed again, if the helper is used in combination with
1931 * direct packet access.
1933 * 0 on success, or a negative error in case of failure.
1935 * int bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
1937 * Retrieve the XFRM state (IP transform framework, see also
1938 * **ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
1940 * The retrieved value is stored in the **struct bpf_xfrm_state**
1941 * pointed by *xfrm_state* and of length *size*.
1943 * All values for *flags* are reserved for future usage, and must
1946 * This helper is available only if the kernel was compiled with
1947 * **CONFIG_XFRM** configuration option.
1949 * 0 on success, or a negative error in case of failure.
1951 * int bpf_get_stack(void *ctx, void *buf, u32 size, u64 flags)
1953 * Return a user or a kernel stack in bpf program provided buffer.
1954 * To achieve this, the helper needs *ctx*, which is a pointer
1955 * to the context on which the tracing program is executed.
1956 * To store the stacktrace, the bpf program provides *buf* with
1957 * a nonnegative *size*.
1959 * The last argument, *flags*, holds the number of stack frames to
1960 * skip (from 0 to 255), masked with
1961 * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
1962 * the following flags:
1964 * **BPF_F_USER_STACK**
1965 * Collect a user space stack instead of a kernel stack.
1966 * **BPF_F_USER_BUILD_ID**
1967 * Collect buildid+offset instead of ips for user stack,
1968 * only valid if **BPF_F_USER_STACK** is also specified.
1970 * **bpf_get_stack**\ () can collect up to
1971 * **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
1972 * to sufficient large buffer size. Note that
1973 * this limit can be controlled with the **sysctl** program, and
1974 * that it should be manually increased in order to profile long
1975 * user stacks (such as stacks for Java programs). To do so, use:
1979 * # sysctl kernel.perf_event_max_stack=<new value>
1981 * A non-negative value equal to or less than *size* on success,
1982 * or a negative error in case of failure.
1984 * int bpf_skb_load_bytes_relative(const void *skb, u32 offset, void *to, u32 len, u32 start_header)
1986 * This helper is similar to **bpf_skb_load_bytes**\ () in that
1987 * it provides an easy way to load *len* bytes from *offset*
1988 * from the packet associated to *skb*, into the buffer pointed
1989 * by *to*. The difference to **bpf_skb_load_bytes**\ () is that
1990 * a fifth argument *start_header* exists in order to select a
1991 * base offset to start from. *start_header* can be one of:
1993 * **BPF_HDR_START_MAC**
1994 * Base offset to load data from is *skb*'s mac header.
1995 * **BPF_HDR_START_NET**
1996 * Base offset to load data from is *skb*'s network header.
1998 * In general, "direct packet access" is the preferred method to
1999 * access packet data, however, this helper is in particular useful
2000 * in socket filters where *skb*\ **->data** does not always point
2001 * to the start of the mac header and where "direct packet access"
2004 * 0 on success, or a negative error in case of failure.
2006 * int bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
2008 * Do FIB lookup in kernel tables using parameters in *params*.
2009 * If lookup is successful and result shows packet is to be
2010 * forwarded, the neighbor tables are searched for the nexthop.
2011 * If successful (ie., FIB lookup shows forwarding and nexthop
2012 * is resolved), the nexthop address is returned in ipv4_dst
2013 * or ipv6_dst based on family, smac is set to mac address of
2014 * egress device, dmac is set to nexthop mac address, rt_metric
2015 * is set to metric from route (IPv4/IPv6 only), and ifindex
2016 * is set to the device index of the nexthop from the FIB lookup.
2018 * *plen* argument is the size of the passed in struct.
2019 * *flags* argument can be a combination of one or more of the
2022 * **BPF_FIB_LOOKUP_DIRECT**
2023 * Do a direct table lookup vs full lookup using FIB
2025 * **BPF_FIB_LOOKUP_OUTPUT**
2026 * Perform lookup from an egress perspective (default is
2029 * *ctx* is either **struct xdp_md** for XDP programs or
2030 * **struct sk_buff** tc cls_act programs.
2032 * * < 0 if any input argument is invalid
2033 * * 0 on success (packet is forwarded, nexthop neighbor exists)
2034 * * > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
2035 * packet is not forwarded or needs assist from full stack
2037 * int bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
2039 * Add an entry to, or update a sockhash *map* referencing sockets.
2040 * The *skops* is used as a new value for the entry associated to
2041 * *key*. *flags* is one of:
2044 * The entry for *key* must not exist in the map.
2046 * The entry for *key* must already exist in the map.
2048 * No condition on the existence of the entry for *key*.
2050 * If the *map* has eBPF programs (parser and verdict), those will
2051 * be inherited by the socket being added. If the socket is
2052 * already attached to eBPF programs, this results in an error.
2054 * 0 on success, or a negative error in case of failure.
2056 * int bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
2058 * This helper is used in programs implementing policies at the
2059 * socket level. If the message *msg* is allowed to pass (i.e. if
2060 * the verdict eBPF program returns **SK_PASS**), redirect it to
2061 * the socket referenced by *map* (of type
2062 * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
2063 * egress interfaces can be used for redirection. The
2064 * **BPF_F_INGRESS** value in *flags* is used to make the
2065 * distinction (ingress path is selected if the flag is present,
2066 * egress path otherwise). This is the only flag supported for now.
2068 * **SK_PASS** on success, or **SK_DROP** on error.
2070 * int bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
2072 * This helper is used in programs implementing policies at the
2073 * skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
2074 * if the verdeict eBPF program returns **SK_PASS**), redirect it
2075 * to the socket referenced by *map* (of type
2076 * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
2077 * egress interfaces can be used for redirection. The
2078 * **BPF_F_INGRESS** value in *flags* is used to make the
2079 * distinction (ingress path is selected if the flag is present,
2080 * egress otherwise). This is the only flag supported for now.
2082 * **SK_PASS** on success, or **SK_DROP** on error.
2084 * int bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
2086 * Encapsulate the packet associated to *skb* within a Layer 3
2087 * protocol header. This header is provided in the buffer at
2088 * address *hdr*, with *len* its size in bytes. *type* indicates
2089 * the protocol of the header and can be one of:
2091 * **BPF_LWT_ENCAP_SEG6**
2092 * IPv6 encapsulation with Segment Routing Header
2093 * (**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
2094 * the IPv6 header is computed by the kernel.
2095 * **BPF_LWT_ENCAP_SEG6_INLINE**
2096 * Only works if *skb* contains an IPv6 packet. Insert a
2097 * Segment Routing Header (**struct ipv6_sr_hdr**) inside
2099 * **BPF_LWT_ENCAP_IP**
2100 * IP encapsulation (GRE/GUE/IPIP/etc). The outer header
2101 * must be IPv4 or IPv6, followed by zero or more
2102 * additional headers, up to **LWT_BPF_MAX_HEADROOM**
2103 * total bytes in all prepended headers. Please note that
2104 * if **skb_is_gso**\ (*skb*) is true, no more than two
2105 * headers can be prepended, and the inner header, if
2106 * present, should be either GRE or UDP/GUE.
2108 * **BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs
2109 * of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can
2110 * be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and
2111 * **BPF_PROG_TYPE_LWT_XMIT**.
2113 * A call to this helper is susceptible to change the underlying
2114 * packet buffer. Therefore, at load time, all checks on pointers
2115 * previously done by the verifier are invalidated and must be
2116 * performed again, if the helper is used in combination with
2117 * direct packet access.
2119 * 0 on success, or a negative error in case of failure.
2121 * int bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
2123 * Store *len* bytes from address *from* into the packet
2124 * associated to *skb*, at *offset*. Only the flags, tag and TLVs
2125 * inside the outermost IPv6 Segment Routing Header can be
2126 * modified through this helper.
2128 * A call to this helper is susceptible to change the underlying
2129 * packet buffer. Therefore, at load time, all checks on pointers
2130 * previously done by the verifier are invalidated and must be
2131 * performed again, if the helper is used in combination with
2132 * direct packet access.
2134 * 0 on success, or a negative error in case of failure.
2136 * int bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
2138 * Adjust the size allocated to TLVs in the outermost IPv6
2139 * Segment Routing Header contained in the packet associated to
2140 * *skb*, at position *offset* by *delta* bytes. Only offsets
2141 * after the segments are accepted. *delta* can be as well
2142 * positive (growing) as negative (shrinking).
2144 * A call to this helper is susceptible to change the underlying
2145 * packet buffer. Therefore, at load time, all checks on pointers
2146 * previously done by the verifier are invalidated and must be
2147 * performed again, if the helper is used in combination with
2148 * direct packet access.
2150 * 0 on success, or a negative error in case of failure.
2152 * int bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
2154 * Apply an IPv6 Segment Routing action of type *action* to the
2155 * packet associated to *skb*. Each action takes a parameter
2156 * contained at address *param*, and of length *param_len* bytes.
2157 * *action* can be one of:
2159 * **SEG6_LOCAL_ACTION_END_X**
2160 * End.X action: Endpoint with Layer-3 cross-connect.
2161 * Type of *param*: **struct in6_addr**.
2162 * **SEG6_LOCAL_ACTION_END_T**
2163 * End.T action: Endpoint with specific IPv6 table lookup.
2164 * Type of *param*: **int**.
2165 * **SEG6_LOCAL_ACTION_END_B6**
2166 * End.B6 action: Endpoint bound to an SRv6 policy.
2167 * Type of *param*: **struct ipv6_sr_hdr**.
2168 * **SEG6_LOCAL_ACTION_END_B6_ENCAP**
2169 * End.B6.Encap action: Endpoint bound to an SRv6
2170 * encapsulation policy.
2171 * Type of *param*: **struct ipv6_sr_hdr**.
2173 * A call to this helper is susceptible to change the underlying
2174 * packet buffer. Therefore, at load time, all checks on pointers
2175 * previously done by the verifier are invalidated and must be
2176 * performed again, if the helper is used in combination with
2177 * direct packet access.
2179 * 0 on success, or a negative error in case of failure.
2181 * int bpf_rc_repeat(void *ctx)
2183 * This helper is used in programs implementing IR decoding, to
2184 * report a successfully decoded repeat key message. This delays
2185 * the generation of a key up event for previously generated
2188 * Some IR protocols like NEC have a special IR message for
2189 * repeating last button, for when a button is held down.
2191 * The *ctx* should point to the lirc sample as passed into
2194 * This helper is only available is the kernel was compiled with
2195 * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
2200 * int bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
2202 * This helper is used in programs implementing IR decoding, to
2203 * report a successfully decoded key press with *scancode*,
2204 * *toggle* value in the given *protocol*. The scancode will be
2205 * translated to a keycode using the rc keymap, and reported as
2206 * an input key down event. After a period a key up event is
2207 * generated. This period can be extended by calling either
2208 * **bpf_rc_keydown**\ () again with the same values, or calling
2209 * **bpf_rc_repeat**\ ().
2211 * Some protocols include a toggle bit, in case the button was
2212 * released and pressed again between consecutive scancodes.
2214 * The *ctx* should point to the lirc sample as passed into
2217 * The *protocol* is the decoded protocol number (see
2218 * **enum rc_proto** for some predefined values).
2220 * This helper is only available is the kernel was compiled with
2221 * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
2226 * u64 bpf_skb_cgroup_id(struct sk_buff *skb)
2228 * Return the cgroup v2 id of the socket associated with the *skb*.
2229 * This is roughly similar to the **bpf_get_cgroup_classid**\ ()
2230 * helper for cgroup v1 by providing a tag resp. identifier that
2231 * can be matched on or used for map lookups e.g. to implement
2232 * policy. The cgroup v2 id of a given path in the hierarchy is
2233 * exposed in user space through the f_handle API in order to get
2234 * to the same 64-bit id.
2236 * This helper can be used on TC egress path, but not on ingress,
2237 * and is available only if the kernel was compiled with the
2238 * **CONFIG_SOCK_CGROUP_DATA** configuration option.
2240 * The id is returned or 0 in case the id could not be retrieved.
2242 * u64 bpf_get_current_cgroup_id(void)
2244 * A 64-bit integer containing the current cgroup id based
2245 * on the cgroup within which the current task is running.
2247 * void *bpf_get_local_storage(void *map, u64 flags)
2249 * Get the pointer to the local storage area.
2250 * The type and the size of the local storage is defined
2251 * by the *map* argument.
2252 * The *flags* meaning is specific for each map type,
2253 * and has to be 0 for cgroup local storage.
2255 * Depending on the BPF program type, a local storage area
2256 * can be shared between multiple instances of the BPF program,
2257 * running simultaneously.
2259 * A user should care about the synchronization by himself.
2260 * For example, by using the **BPF_STX_XADD** instruction to alter
2263 * A pointer to the local storage area.
2265 * int bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
2267 * Select a **SO_REUSEPORT** socket from a
2268 * **BPF_MAP_TYPE_REUSEPORT_ARRAY** *map*.
2269 * It checks the selected socket is matching the incoming
2270 * request in the socket buffer.
2272 * 0 on success, or a negative error in case of failure.
2274 * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
2276 * Return id of cgroup v2 that is ancestor of cgroup associated
2277 * with the *skb* at the *ancestor_level*. The root cgroup is at
2278 * *ancestor_level* zero and each step down the hierarchy
2279 * increments the level. If *ancestor_level* == level of cgroup
2280 * associated with *skb*, then return value will be same as that
2281 * of **bpf_skb_cgroup_id**\ ().
2283 * The helper is useful to implement policies based on cgroups
2284 * that are upper in hierarchy than immediate cgroup associated
2287 * The format of returned id and helper limitations are same as in
2288 * **bpf_skb_cgroup_id**\ ().
2290 * The id is returned or 0 in case the id could not be retrieved.
2292 * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
2294 * Look for TCP socket matching *tuple*, optionally in a child
2295 * network namespace *netns*. The return value must be checked,
2296 * and if non-**NULL**, released via **bpf_sk_release**\ ().
2298 * The *ctx* should point to the context of the program, such as
2299 * the skb or socket (depending on the hook in use). This is used
2300 * to determine the base network namespace for the lookup.
2302 * *tuple_size* must be one of:
2304 * **sizeof**\ (*tuple*\ **->ipv4**)
2305 * Look for an IPv4 socket.
2306 * **sizeof**\ (*tuple*\ **->ipv6**)
2307 * Look for an IPv6 socket.
2309 * If the *netns* is a negative signed 32-bit integer, then the
2310 * socket lookup table in the netns associated with the *ctx* will
2311 * will be used. For the TC hooks, this is the netns of the device
2312 * in the skb. For socket hooks, this is the netns of the socket.
2313 * If *netns* is any other signed 32-bit value greater than or
2314 * equal to zero then it specifies the ID of the netns relative to
2315 * the netns associated with the *ctx*. *netns* values beyond the
2316 * range of 32-bit integers are reserved for future use.
2318 * All values for *flags* are reserved for future usage, and must
2321 * This helper is available only if the kernel was compiled with
2322 * **CONFIG_NET** configuration option.
2324 * Pointer to **struct bpf_sock**, or **NULL** in case of failure.
2325 * For sockets with reuseport option, the **struct bpf_sock**
2326 * result is from *reuse*\ **->socks**\ [] using the hash of the
2329 * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
2331 * Look for UDP socket matching *tuple*, optionally in a child
2332 * network namespace *netns*. The return value must be checked,
2333 * and if non-**NULL**, released via **bpf_sk_release**\ ().
2335 * The *ctx* should point to the context of the program, such as
2336 * the skb or socket (depending on the hook in use). This is used
2337 * to determine the base network namespace for the lookup.
2339 * *tuple_size* must be one of:
2341 * **sizeof**\ (*tuple*\ **->ipv4**)
2342 * Look for an IPv4 socket.
2343 * **sizeof**\ (*tuple*\ **->ipv6**)
2344 * Look for an IPv6 socket.
2346 * If the *netns* is a negative signed 32-bit integer, then the
2347 * socket lookup table in the netns associated with the *ctx* will
2348 * will be used. For the TC hooks, this is the netns of the device
2349 * in the skb. For socket hooks, this is the netns of the socket.
2350 * If *netns* is any other signed 32-bit value greater than or
2351 * equal to zero then it specifies the ID of the netns relative to
2352 * the netns associated with the *ctx*. *netns* values beyond the
2353 * range of 32-bit integers are reserved for future use.
2355 * All values for *flags* are reserved for future usage, and must
2358 * This helper is available only if the kernel was compiled with
2359 * **CONFIG_NET** configuration option.
2361 * Pointer to **struct bpf_sock**, or **NULL** in case of failure.
2362 * For sockets with reuseport option, the **struct bpf_sock**
2363 * result is from *reuse*\ **->socks**\ [] using the hash of the
2366 * int bpf_sk_release(struct bpf_sock *sock)
2368 * Release the reference held by *sock*. *sock* must be a
2369 * non-**NULL** pointer that was returned from
2370 * **bpf_sk_lookup_xxx**\ ().
2372 * 0 on success, or a negative error in case of failure.
2374 * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
2376 * Push an element *value* in *map*. *flags* is one of:
2379 * If the queue/stack is full, the oldest element is
2380 * removed to make room for this.
2382 * 0 on success, or a negative error in case of failure.
2384 * int bpf_map_pop_elem(struct bpf_map *map, void *value)
2386 * Pop an element from *map*.
2388 * 0 on success, or a negative error in case of failure.
2390 * int bpf_map_peek_elem(struct bpf_map *map, void *value)
2392 * Get an element from *map* without removing it.
2394 * 0 on success, or a negative error in case of failure.
2396 * int bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
2398 * For socket policies, insert *len* bytes into *msg* at offset
2401 * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
2402 * *msg* it may want to insert metadata or options into the *msg*.
2403 * This can later be read and used by any of the lower layer BPF
2406 * This helper may fail if under memory pressure (a malloc
2407 * fails) in these cases BPF programs will get an appropriate
2408 * error and BPF programs will need to handle them.
2410 * 0 on success, or a negative error in case of failure.
2412 * int bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
2414 * Will remove *len* bytes from a *msg* starting at byte *start*.
2415 * This may result in **ENOMEM** errors under certain situations if
2416 * an allocation and copy are required due to a full ring buffer.
2417 * However, the helper will try to avoid doing the allocation
2418 * if possible. Other errors can occur if input parameters are
2419 * invalid either due to *start* byte not being valid part of *msg*
2420 * payload and/or *pop* value being to large.
2422 * 0 on success, or a negative error in case of failure.
2424 * int bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
2426 * This helper is used in programs implementing IR decoding, to
2427 * report a successfully decoded pointer movement.
2429 * The *ctx* should point to the lirc sample as passed into
2432 * This helper is only available is the kernel was compiled with
2433 * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
2438 * int bpf_spin_lock(struct bpf_spin_lock *lock)
2440 * Acquire a spinlock represented by the pointer *lock*, which is
2441 * stored as part of a value of a map. Taking the lock allows to
2442 * safely update the rest of the fields in that value. The
2443 * spinlock can (and must) later be released with a call to
2444 * **bpf_spin_unlock**\ (\ *lock*\ ).
2446 * Spinlocks in BPF programs come with a number of restrictions
2449 * * **bpf_spin_lock** objects are only allowed inside maps of
2450 * types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
2451 * list could be extended in the future).
2452 * * BTF description of the map is mandatory.
2453 * * The BPF program can take ONE lock at a time, since taking two
2454 * or more could cause dead locks.
2455 * * Only one **struct bpf_spin_lock** is allowed per map element.
2456 * * When the lock is taken, calls (either BPF to BPF or helpers)
2458 * * The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
2459 * allowed inside a spinlock-ed region.
2460 * * The BPF program MUST call **bpf_spin_unlock**\ () to release
2461 * the lock, on all execution paths, before it returns.
2462 * * The BPF program can access **struct bpf_spin_lock** only via
2463 * the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
2464 * helpers. Loading or storing data into the **struct
2465 * bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
2466 * * To use the **bpf_spin_lock**\ () helper, the BTF description
2467 * of the map value must be a struct and have **struct
2468 * bpf_spin_lock** *anyname*\ **;** field at the top level.
2469 * Nested lock inside another struct is not allowed.
2470 * * The **struct bpf_spin_lock** *lock* field in a map value must
2471 * be aligned on a multiple of 4 bytes in that value.
2472 * * Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
2473 * the **bpf_spin_lock** field to user space.
2474 * * Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
2475 * a BPF program, do not update the **bpf_spin_lock** field.
2476 * * **bpf_spin_lock** cannot be on the stack or inside a
2477 * networking packet (it can only be inside of a map values).
2478 * * **bpf_spin_lock** is available to root only.
2479 * * Tracing programs and socket filter programs cannot use
2480 * **bpf_spin_lock**\ () due to insufficient preemption checks
2481 * (but this may change in the future).
2482 * * **bpf_spin_lock** is not allowed in inner maps of map-in-map.
2486 * int bpf_spin_unlock(struct bpf_spin_lock *lock)
2488 * Release the *lock* previously locked by a call to
2489 * **bpf_spin_lock**\ (\ *lock*\ ).
2493 * struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
2495 * This helper gets a **struct bpf_sock** pointer such
2496 * that all the fields in this **bpf_sock** can be accessed.
2498 * A **struct bpf_sock** pointer on success, or **NULL** in
2501 * struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
2503 * This helper gets a **struct bpf_tcp_sock** pointer from a
2504 * **struct bpf_sock** pointer.
2506 * A **struct bpf_tcp_sock** pointer on success, or **NULL** in
2509 * int bpf_skb_ecn_set_ce(struct sk_buff *skb)
2511 * Set ECN (Explicit Congestion Notification) field of IP header
2512 * to **CE** (Congestion Encountered) if current value is **ECT**
2513 * (ECN Capable Transport). Otherwise, do nothing. Works with IPv6
2516 * 1 if the **CE** flag is set (either by the current helper call
2517 * or because it was already present), 0 if it is not set.
2519 * struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)
2521 * Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
2522 * **bpf_sk_release**\ () is unnecessary and not allowed.
2524 * A **struct bpf_sock** pointer on success, or **NULL** in
2527 * struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
2529 * Look for TCP socket matching *tuple*, optionally in a child
2530 * network namespace *netns*. The return value must be checked,
2531 * and if non-**NULL**, released via **bpf_sk_release**\ ().
2533 * This function is identical to **bpf_sk_lookup_tcp**\ (), except
2534 * that it also returns timewait or request sockets. Use
2535 * **bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the
2538 * This helper is available only if the kernel was compiled with
2539 * **CONFIG_NET** configuration option.
2541 * Pointer to **struct bpf_sock**, or **NULL** in case of failure.
2542 * For sockets with reuseport option, the **struct bpf_sock**
2543 * result is from *reuse*\ **->socks**\ [] using the hash of the
2546 * int bpf_tcp_check_syncookie(struct bpf_sock *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
2548 * Check whether *iph* and *th* contain a valid SYN cookie ACK for
2549 * the listening socket in *sk*.
2551 * *iph* points to the start of the IPv4 or IPv6 header, while
2552 * *iph_len* contains **sizeof**\ (**struct iphdr**) or
2553 * **sizeof**\ (**struct ip6hdr**).
2555 * *th* points to the start of the TCP header, while *th_len*
2556 * contains **sizeof**\ (**struct tcphdr**).
2559 * 0 if *iph* and *th* are a valid SYN cookie ACK, or a negative
2562 * int bpf_sysctl_get_name(struct bpf_sysctl *ctx, char *buf, size_t buf_len, u64 flags)
2564 * Get name of sysctl in /proc/sys/ and copy it into provided by
2565 * program buffer *buf* of size *buf_len*.
2567 * The buffer is always NUL terminated, unless it's zero-sized.
2569 * If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is
2570 * copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name
2571 * only (e.g. "tcp_mem").
2573 * Number of character copied (not including the trailing NUL).
2575 * **-E2BIG** if the buffer wasn't big enough (*buf* will contain
2576 * truncated name in this case).
2578 * int bpf_sysctl_get_current_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
2580 * Get current value of sysctl as it is presented in /proc/sys
2581 * (incl. newline, etc), and copy it as a string into provided
2582 * by program buffer *buf* of size *buf_len*.
2584 * The whole value is copied, no matter what file position user
2585 * space issued e.g. sys_read at.
2587 * The buffer is always NUL terminated, unless it's zero-sized.
2589 * Number of character copied (not including the trailing NUL).
2591 * **-E2BIG** if the buffer wasn't big enough (*buf* will contain
2592 * truncated name in this case).
2594 * **-EINVAL** if current value was unavailable, e.g. because
2595 * sysctl is uninitialized and read returns -EIO for it.
2597 * int bpf_sysctl_get_new_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
2599 * Get new value being written by user space to sysctl (before
2600 * the actual write happens) and copy it as a string into
2601 * provided by program buffer *buf* of size *buf_len*.
2603 * User space may write new value at file position > 0.
2605 * The buffer is always NUL terminated, unless it's zero-sized.
2607 * Number of character copied (not including the trailing NUL).
2609 * **-E2BIG** if the buffer wasn't big enough (*buf* will contain
2610 * truncated name in this case).
2612 * **-EINVAL** if sysctl is being read.
2614 * int bpf_sysctl_set_new_value(struct bpf_sysctl *ctx, const char *buf, size_t buf_len)
2616 * Override new value being written by user space to sysctl with
2617 * value provided by program in buffer *buf* of size *buf_len*.
2619 * *buf* should contain a string in same form as provided by user
2620 * space on sysctl write.
2622 * User space may write new value at file position > 0. To override
2623 * the whole sysctl value file position should be set to zero.
2627 * **-E2BIG** if the *buf_len* is too big.
2629 * **-EINVAL** if sysctl is being read.
2631 * int bpf_strtol(const char *buf, size_t buf_len, u64 flags, long *res)
2633 * Convert the initial part of the string from buffer *buf* of
2634 * size *buf_len* to a long integer according to the given base
2635 * and save the result in *res*.
2637 * The string may begin with an arbitrary amount of white space
2638 * (as determined by **isspace**\ (3)) followed by a single
2639 * optional '**-**' sign.
2641 * Five least significant bits of *flags* encode base, other bits
2642 * are currently unused.
2644 * Base must be either 8, 10, 16 or 0 to detect it automatically
2645 * similar to user space **strtol**\ (3).
2647 * Number of characters consumed on success. Must be positive but
2648 * no more than *buf_len*.
2650 * **-EINVAL** if no valid digits were found or unsupported base
2653 * **-ERANGE** if resulting value was out of range.
2655 * int bpf_strtoul(const char *buf, size_t buf_len, u64 flags, unsigned long *res)
2657 * Convert the initial part of the string from buffer *buf* of
2658 * size *buf_len* to an unsigned long integer according to the
2659 * given base and save the result in *res*.
2661 * The string may begin with an arbitrary amount of white space
2662 * (as determined by **isspace**\ (3)).
2664 * Five least significant bits of *flags* encode base, other bits
2665 * are currently unused.
2667 * Base must be either 8, 10, 16 or 0 to detect it automatically
2668 * similar to user space **strtoul**\ (3).
2670 * Number of characters consumed on success. Must be positive but
2671 * no more than *buf_len*.
2673 * **-EINVAL** if no valid digits were found or unsupported base
2676 * **-ERANGE** if resulting value was out of range.
2678 * void *bpf_sk_storage_get(struct bpf_map *map, struct bpf_sock *sk, void *value, u64 flags)
2680 * Get a bpf-local-storage from a *sk*.
2682 * Logically, it could be thought of getting the value from
2683 * a *map* with *sk* as the **key**. From this
2684 * perspective, the usage is not much different from
2685 * **bpf_map_lookup_elem**\ (*map*, **&**\ *sk*) except this
2686 * helper enforces the key must be a full socket and the map must
2687 * be a **BPF_MAP_TYPE_SK_STORAGE** also.
2689 * Underneath, the value is stored locally at *sk* instead of
2690 * the *map*. The *map* is used as the bpf-local-storage
2691 * "type". The bpf-local-storage "type" (i.e. the *map*) is
2692 * searched against all bpf-local-storages residing at *sk*.
2694 * An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
2695 * used such that a new bpf-local-storage will be
2696 * created if one does not exist. *value* can be used
2697 * together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
2698 * the initial value of a bpf-local-storage. If *value* is
2699 * **NULL**, the new bpf-local-storage will be zero initialized.
2701 * A bpf-local-storage pointer is returned on success.
2703 * **NULL** if not found or there was an error in adding
2704 * a new bpf-local-storage.
2706 * int bpf_sk_storage_delete(struct bpf_map *map, struct bpf_sock *sk)
2708 * Delete a bpf-local-storage from a *sk*.
2712 * **-ENOENT** if the bpf-local-storage cannot be found.
2714 * int bpf_send_signal(u32 sig)
2716 * Send signal *sig* to the current task.
2718 * 0 on success or successfully queued.
2720 * **-EBUSY** if work queue under nmi is full.
2722 * **-EINVAL** if *sig* is invalid.
2724 * **-EPERM** if no permission to send the *sig*.
2726 * **-EAGAIN** if bpf program can try again.
2728 * s64 bpf_tcp_gen_syncookie(struct bpf_sock *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
2730 * Try to issue a SYN cookie for the packet with corresponding
2731 * IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
2733 * *iph* points to the start of the IPv4 or IPv6 header, while
2734 * *iph_len* contains **sizeof**\ (**struct iphdr**) or
2735 * **sizeof**\ (**struct ip6hdr**).
2737 * *th* points to the start of the TCP header, while *th_len*
2738 * contains the length of the TCP header.
2741 * On success, lower 32 bits hold the generated SYN cookie in
2742 * followed by 16 bits which hold the MSS value for that cookie,
2743 * and the top 16 bits are unused.
2745 * On failure, the returned value is one of the following:
2747 * **-EINVAL** SYN cookie cannot be issued due to error
2749 * **-ENOENT** SYN cookie should not be issued (no SYN flood)
2751 * **-EOPNOTSUPP** kernel configuration does not enable SYN cookies
2753 * **-EPROTONOSUPPORT** IP packet version is not 4 or 6
2755 * int bpf_skb_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
2757 * Write raw *data* blob into a special BPF perf event held by
2758 * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
2759 * event must have the following attributes: **PERF_SAMPLE_RAW**
2760 * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
2761 * **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
2763 * The *flags* are used to indicate the index in *map* for which
2764 * the value must be put, masked with **BPF_F_INDEX_MASK**.
2765 * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
2766 * to indicate that the index of the current CPU core should be
2769 * The value to write, of *size*, is passed through eBPF stack and
2770 * pointed by *data*.
2772 * *ctx* is a pointer to in-kernel struct sk_buff.
2774 * This helper is similar to **bpf_perf_event_output**\ () but
2775 * restricted to raw_tracepoint bpf programs.
2777 * 0 on success, or a negative error in case of failure.
2779 #define __BPF_FUNC_MAPPER(FN) \
2781 FN(map_lookup_elem), \
2782 FN(map_update_elem), \
2783 FN(map_delete_elem), \
2787 FN(get_prandom_u32), \
2788 FN(get_smp_processor_id), \
2789 FN(skb_store_bytes), \
2790 FN(l3_csum_replace), \
2791 FN(l4_csum_replace), \
2793 FN(clone_redirect), \
2794 FN(get_current_pid_tgid), \
2795 FN(get_current_uid_gid), \
2796 FN(get_current_comm), \
2797 FN(get_cgroup_classid), \
2798 FN(skb_vlan_push), \
2800 FN(skb_get_tunnel_key), \
2801 FN(skb_set_tunnel_key), \
2802 FN(perf_event_read), \
2804 FN(get_route_realm), \
2805 FN(perf_event_output), \
2806 FN(skb_load_bytes), \
2809 FN(skb_get_tunnel_opt), \
2810 FN(skb_set_tunnel_opt), \
2811 FN(skb_change_proto), \
2812 FN(skb_change_type), \
2813 FN(skb_under_cgroup), \
2814 FN(get_hash_recalc), \
2815 FN(get_current_task), \
2816 FN(probe_write_user), \
2817 FN(current_task_under_cgroup), \
2818 FN(skb_change_tail), \
2819 FN(skb_pull_data), \
2821 FN(set_hash_invalid), \
2822 FN(get_numa_node_id), \
2823 FN(skb_change_head), \
2824 FN(xdp_adjust_head), \
2825 FN(probe_read_str), \
2826 FN(get_socket_cookie), \
2827 FN(get_socket_uid), \
2830 FN(skb_adjust_room), \
2832 FN(sk_redirect_map), \
2833 FN(sock_map_update), \
2834 FN(xdp_adjust_meta), \
2835 FN(perf_event_read_value), \
2836 FN(perf_prog_read_value), \
2838 FN(override_return), \
2839 FN(sock_ops_cb_flags_set), \
2840 FN(msg_redirect_map), \
2841 FN(msg_apply_bytes), \
2842 FN(msg_cork_bytes), \
2843 FN(msg_pull_data), \
2845 FN(xdp_adjust_tail), \
2846 FN(skb_get_xfrm_state), \
2848 FN(skb_load_bytes_relative), \
2850 FN(sock_hash_update), \
2851 FN(msg_redirect_hash), \
2852 FN(sk_redirect_hash), \
2853 FN(lwt_push_encap), \
2854 FN(lwt_seg6_store_bytes), \
2855 FN(lwt_seg6_adjust_srh), \
2856 FN(lwt_seg6_action), \
2859 FN(skb_cgroup_id), \
2860 FN(get_current_cgroup_id), \
2861 FN(get_local_storage), \
2862 FN(sk_select_reuseport), \
2863 FN(skb_ancestor_cgroup_id), \
2864 FN(sk_lookup_tcp), \
2865 FN(sk_lookup_udp), \
2867 FN(map_push_elem), \
2869 FN(map_peek_elem), \
2870 FN(msg_push_data), \
2872 FN(rc_pointer_rel), \
2877 FN(skb_ecn_set_ce), \
2878 FN(get_listener_sock), \
2879 FN(skc_lookup_tcp), \
2880 FN(tcp_check_syncookie), \
2881 FN(sysctl_get_name), \
2882 FN(sysctl_get_current_value), \
2883 FN(sysctl_get_new_value), \
2884 FN(sysctl_set_new_value), \
2887 FN(sk_storage_get), \
2888 FN(sk_storage_delete), \
2890 FN(tcp_gen_syncookie), \
2893 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
2894 * function eBPF program intends to call
2896 #define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
2898 __BPF_FUNC_MAPPER(__BPF_ENUM_FN)
2901 #undef __BPF_ENUM_FN
2903 /* All flags used by eBPF helper functions, placed here. */
2905 /* BPF_FUNC_skb_store_bytes flags. */
2906 #define BPF_F_RECOMPUTE_CSUM (1ULL << 0)
2907 #define BPF_F_INVALIDATE_HASH (1ULL << 1)
2909 /* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
2910 * First 4 bits are for passing the header field size.
2912 #define BPF_F_HDR_FIELD_MASK 0xfULL
2914 /* BPF_FUNC_l4_csum_replace flags. */
2915 #define BPF_F_PSEUDO_HDR (1ULL << 4)
2916 #define BPF_F_MARK_MANGLED_0 (1ULL << 5)
2917 #define BPF_F_MARK_ENFORCE (1ULL << 6)
2919 /* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
2920 #define BPF_F_INGRESS (1ULL << 0)
2922 /* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
2923 #define BPF_F_TUNINFO_IPV6 (1ULL << 0)
2925 /* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
2926 #define BPF_F_SKIP_FIELD_MASK 0xffULL
2927 #define BPF_F_USER_STACK (1ULL << 8)
2928 /* flags used by BPF_FUNC_get_stackid only. */
2929 #define BPF_F_FAST_STACK_CMP (1ULL << 9)
2930 #define BPF_F_REUSE_STACKID (1ULL << 10)
2931 /* flags used by BPF_FUNC_get_stack only. */
2932 #define BPF_F_USER_BUILD_ID (1ULL << 11)
2934 /* BPF_FUNC_skb_set_tunnel_key flags. */
2935 #define BPF_F_ZERO_CSUM_TX (1ULL << 1)
2936 #define BPF_F_DONT_FRAGMENT (1ULL << 2)
2937 #define BPF_F_SEQ_NUMBER (1ULL << 3)
2939 /* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
2940 * BPF_FUNC_perf_event_read_value flags.
2942 #define BPF_F_INDEX_MASK 0xffffffffULL
2943 #define BPF_F_CURRENT_CPU BPF_F_INDEX_MASK
2944 /* BPF_FUNC_perf_event_output for sk_buff input context. */
2945 #define BPF_F_CTXLEN_MASK (0xfffffULL << 32)
2947 /* Current network namespace */
2948 #define BPF_F_CURRENT_NETNS (-1L)
2950 /* BPF_FUNC_skb_adjust_room flags. */
2951 #define BPF_F_ADJ_ROOM_FIXED_GSO (1ULL << 0)
2953 #define BPF_ADJ_ROOM_ENCAP_L2_MASK 0xff
2954 #define BPF_ADJ_ROOM_ENCAP_L2_SHIFT 56
2956 #define BPF_F_ADJ_ROOM_ENCAP_L3_IPV4 (1ULL << 1)
2957 #define BPF_F_ADJ_ROOM_ENCAP_L3_IPV6 (1ULL << 2)
2958 #define BPF_F_ADJ_ROOM_ENCAP_L4_GRE (1ULL << 3)
2959 #define BPF_F_ADJ_ROOM_ENCAP_L4_UDP (1ULL << 4)
2960 #define BPF_F_ADJ_ROOM_ENCAP_L2(len) (((__u64)len & \
2961 BPF_ADJ_ROOM_ENCAP_L2_MASK) \
2962 << BPF_ADJ_ROOM_ENCAP_L2_SHIFT)
2964 /* BPF_FUNC_sysctl_get_name flags. */
2965 #define BPF_F_SYSCTL_BASE_NAME (1ULL << 0)
2967 /* BPF_FUNC_sk_storage_get flags */
2968 #define BPF_SK_STORAGE_GET_F_CREATE (1ULL << 0)
2970 /* Mode for BPF_FUNC_skb_adjust_room helper. */
2971 enum bpf_adj_room_mode {
2976 /* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
2977 enum bpf_hdr_start_off {
2982 /* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
2983 enum bpf_lwt_encap_mode {
2985 BPF_LWT_ENCAP_SEG6_INLINE,
2989 #define __bpf_md_ptr(type, name) \
2993 } __attribute__((aligned(8)))
2995 /* user accessible mirror of in-kernel sk_buff.
2996 * new fields can only be added to the end of this structure
3002 __u32 queue_mapping;
3008 __u32 ingress_ifindex;
3018 /* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
3020 __u32 remote_ip4; /* Stored in network byte order */
3021 __u32 local_ip4; /* Stored in network byte order */
3022 __u32 remote_ip6[4]; /* Stored in network byte order */
3023 __u32 local_ip6[4]; /* Stored in network byte order */
3024 __u32 remote_port; /* Stored in network byte order */
3025 __u32 local_port; /* stored in host byte order */
3029 __bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
3033 __bpf_md_ptr(struct bpf_sock *, sk);
3036 struct bpf_tunnel_key {
3040 __u32 remote_ipv6[4];
3044 __u16 tunnel_ext; /* Padding, future use. */
3048 /* user accessible mirror of in-kernel xfrm_state.
3049 * new fields can only be added to the end of this structure
3051 struct bpf_xfrm_state {
3053 __u32 spi; /* Stored in network byte order */
3055 __u16 ext; /* Padding, future use. */
3057 __u32 remote_ipv4; /* Stored in network byte order */
3058 __u32 remote_ipv6[4]; /* Stored in network byte order */
3062 /* Generic BPF return codes which all BPF program types may support.
3063 * The values are binary compatible with their TC_ACT_* counter-part to
3064 * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
3067 * XDP is handled seprately, see XDP_*.
3075 /* >127 are reserved for prog type specific return codes.
3077 * BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and
3078 * BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been
3079 * changed and should be routed based on its new L3 header.
3080 * (This is an L3 redirect, as opposed to L2 redirect
3081 * represented by BPF_REDIRECT above).
3083 BPF_LWT_REROUTE = 128,
3093 /* IP address also allows 1 and 2 bytes access */
3096 __u32 src_port; /* host byte order */
3097 __u32 dst_port; /* network byte order */
3103 struct bpf_tcp_sock {
3104 __u32 snd_cwnd; /* Sending congestion window */
3105 __u32 srtt_us; /* smoothed round trip time << 3 in usecs */
3107 __u32 snd_ssthresh; /* Slow start size threshold */
3108 __u32 rcv_nxt; /* What we want to receive next */
3109 __u32 snd_nxt; /* Next sequence we send */
3110 __u32 snd_una; /* First byte we want an ack for */
3111 __u32 mss_cache; /* Cached effective mss, not including SACKS */
3112 __u32 ecn_flags; /* ECN status bits. */
3113 __u32 rate_delivered; /* saved rate sample: packets delivered */
3114 __u32 rate_interval_us; /* saved rate sample: time elapsed */
3115 __u32 packets_out; /* Packets which are "in flight" */
3116 __u32 retrans_out; /* Retransmitted packets out */
3117 __u32 total_retrans; /* Total retransmits for entire connection */
3118 __u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn
3119 * total number of segments in.
3121 __u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn
3122 * total number of data segments in.
3124 __u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut
3125 * The total number of segments sent.
3127 __u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut
3128 * total number of data segments sent.
3130 __u32 lost_out; /* Lost packets */
3131 __u32 sacked_out; /* SACK'd packets */
3132 __u64 bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived
3133 * sum(delta(rcv_nxt)), or how many bytes
3136 __u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked
3137 * sum(delta(snd_una)), or how many bytes
3140 __u32 dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups
3141 * total number of DSACK blocks received
3143 __u32 delivered; /* Total data packets delivered incl. rexmits */
3144 __u32 delivered_ce; /* Like the above but only ECE marked packets */
3145 __u32 icsk_retransmits; /* Number of unrecovered [RTO] timeouts */
3148 struct bpf_sock_tuple {
3165 struct bpf_xdp_sock {
3169 #define XDP_PACKET_HEADROOM 256
3171 /* User return codes for XDP prog type.
3172 * A valid XDP program must return one of these defined values. All other
3173 * return codes are reserved for future use. Unknown return codes will
3174 * result in packet drops and a warning via bpf_warn_invalid_xdp_action().
3184 /* user accessible metadata for XDP packet hook
3185 * new fields must be added to the end of this structure
3191 /* Below access go through struct xdp_rxq_info */
3192 __u32 ingress_ifindex; /* rxq->dev->ifindex */
3193 __u32 rx_queue_index; /* rxq->queue_index */
3201 /* user accessible metadata for SK_MSG packet hook, new fields must
3202 * be added to the end of this structure
3205 __bpf_md_ptr(void *, data);
3206 __bpf_md_ptr(void *, data_end);
3209 __u32 remote_ip4; /* Stored in network byte order */
3210 __u32 local_ip4; /* Stored in network byte order */
3211 __u32 remote_ip6[4]; /* Stored in network byte order */
3212 __u32 local_ip6[4]; /* Stored in network byte order */
3213 __u32 remote_port; /* Stored in network byte order */
3214 __u32 local_port; /* stored in host byte order */
3215 __u32 size; /* Total size of sk_msg */
3218 struct sk_reuseport_md {
3220 * Start of directly accessible data. It begins from
3221 * the tcp/udp header.
3223 __bpf_md_ptr(void *, data);
3224 /* End of directly accessible data */
3225 __bpf_md_ptr(void *, data_end);
3227 * Total length of packet (starting from the tcp/udp header).
3228 * Note that the directly accessible bytes (data_end - data)
3229 * could be less than this "len". Those bytes could be
3230 * indirectly read by a helper "bpf_skb_load_bytes()".
3234 * Eth protocol in the mac header (network byte order). e.g.
3235 * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
3238 __u32 ip_protocol; /* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
3239 __u32 bind_inany; /* Is sock bound to an INANY address? */
3240 __u32 hash; /* A hash of the packet 4 tuples */
3243 #define BPF_TAG_SIZE 8
3245 struct bpf_prog_info {
3248 __u8 tag[BPF_TAG_SIZE];
3249 __u32 jited_prog_len;
3250 __u32 xlated_prog_len;
3251 __aligned_u64 jited_prog_insns;
3252 __aligned_u64 xlated_prog_insns;
3253 __u64 load_time; /* ns since boottime */
3254 __u32 created_by_uid;
3256 __aligned_u64 map_ids;
3257 char name[BPF_OBJ_NAME_LEN];
3259 __u32 gpl_compatible:1;
3260 __u32 :31; /* alignment pad */
3263 __u32 nr_jited_ksyms;
3264 __u32 nr_jited_func_lens;
3265 __aligned_u64 jited_ksyms;
3266 __aligned_u64 jited_func_lens;
3268 __u32 func_info_rec_size;
3269 __aligned_u64 func_info;
3272 __aligned_u64 line_info;
3273 __aligned_u64 jited_line_info;
3274 __u32 nr_jited_line_info;
3275 __u32 line_info_rec_size;
3276 __u32 jited_line_info_rec_size;
3278 __aligned_u64 prog_tags;
3281 } __attribute__((aligned(8)));
3283 struct bpf_map_info {
3290 char name[BPF_OBJ_NAME_LEN];
3296 __u32 btf_key_type_id;
3297 __u32 btf_value_type_id;
3298 } __attribute__((aligned(8)));
3300 struct bpf_btf_info {
3304 } __attribute__((aligned(8)));
3306 /* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
3307 * by user and intended to be used by socket (e.g. to bind to, depends on
3308 * attach attach type).
3310 struct bpf_sock_addr {
3311 __u32 user_family; /* Allows 4-byte read, but no write. */
3312 __u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write.
3313 * Stored in network byte order.
3315 __u32 user_ip6[4]; /* Allows 1,2,4,8-byte read and 4,8-byte write.
3316 * Stored in network byte order.
3318 __u32 user_port; /* Allows 4-byte read and write.
3319 * Stored in network byte order
3321 __u32 family; /* Allows 4-byte read, but no write */
3322 __u32 type; /* Allows 4-byte read, but no write */
3323 __u32 protocol; /* Allows 4-byte read, but no write */
3324 __u32 msg_src_ip4; /* Allows 1,2,4-byte read and 4-byte write.
3325 * Stored in network byte order.
3327 __u32 msg_src_ip6[4]; /* Allows 1,2,4,8-byte read and 4,8-byte write.
3328 * Stored in network byte order.
3330 __bpf_md_ptr(struct bpf_sock *, sk);
3333 /* User bpf_sock_ops struct to access socket values and specify request ops
3334 * and their replies.
3335 * Some of this fields are in network (bigendian) byte order and may need
3336 * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
3337 * New fields can only be added at the end of this structure
3339 struct bpf_sock_ops {
3342 __u32 args[4]; /* Optionally passed to bpf program */
3343 __u32 reply; /* Returned by bpf program */
3344 __u32 replylong[4]; /* Optionally returned by bpf prog */
3347 __u32 remote_ip4; /* Stored in network byte order */
3348 __u32 local_ip4; /* Stored in network byte order */
3349 __u32 remote_ip6[4]; /* Stored in network byte order */
3350 __u32 local_ip6[4]; /* Stored in network byte order */
3351 __u32 remote_port; /* Stored in network byte order */
3352 __u32 local_port; /* stored in host byte order */
3353 __u32 is_fullsock; /* Some TCP fields are only valid if
3354 * there is a full socket. If not, the
3355 * fields read as zero.
3358 __u32 srtt_us; /* Averaged RTT << 3 in usecs */
3359 __u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
3368 __u32 rate_delivered;
3369 __u32 rate_interval_us;
3372 __u32 total_retrans;
3376 __u32 data_segs_out;
3380 __u64 bytes_received;
3382 __bpf_md_ptr(struct bpf_sock *, sk);
3385 /* Definitions for bpf_sock_ops_cb_flags */
3386 #define BPF_SOCK_OPS_RTO_CB_FLAG (1<<0)
3387 #define BPF_SOCK_OPS_RETRANS_CB_FLAG (1<<1)
3388 #define BPF_SOCK_OPS_STATE_CB_FLAG (1<<2)
3389 #define BPF_SOCK_OPS_RTT_CB_FLAG (1<<3)
3390 #define BPF_SOCK_OPS_ALL_CB_FLAGS 0xF /* Mask of all currently
3391 * supported cb flags
3394 /* List of known BPF sock_ops operators.
3395 * New entries can only be added at the end
3399 BPF_SOCK_OPS_TIMEOUT_INIT, /* Should return SYN-RTO value to use or
3400 * -1 if default value should be used
3402 BPF_SOCK_OPS_RWND_INIT, /* Should return initial advertized
3403 * window (in packets) or -1 if default
3404 * value should be used
3406 BPF_SOCK_OPS_TCP_CONNECT_CB, /* Calls BPF program right before an
3407 * active connection is initialized
3409 BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB, /* Calls BPF program when an
3410 * active connection is
3413 BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, /* Calls BPF program when a
3414 * passive connection is
3417 BPF_SOCK_OPS_NEEDS_ECN, /* If connection's congestion control
3420 BPF_SOCK_OPS_BASE_RTT, /* Get base RTT. The correct value is
3421 * based on the path and may be
3422 * dependent on the congestion control
3423 * algorithm. In general it indicates
3424 * a congestion threshold. RTTs above
3425 * this indicate congestion
3427 BPF_SOCK_OPS_RTO_CB, /* Called when an RTO has triggered.
3428 * Arg1: value of icsk_retransmits
3429 * Arg2: value of icsk_rto
3430 * Arg3: whether RTO has expired
3432 BPF_SOCK_OPS_RETRANS_CB, /* Called when skb is retransmitted.
3433 * Arg1: sequence number of 1st byte
3435 * Arg3: return value of
3436 * tcp_transmit_skb (0 => success)
3438 BPF_SOCK_OPS_STATE_CB, /* Called when TCP changes state.
3442 BPF_SOCK_OPS_TCP_LISTEN_CB, /* Called on listen(2), right after
3443 * socket transition to LISTEN state.
3445 BPF_SOCK_OPS_RTT_CB, /* Called on every RTT.
3449 /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
3450 * changes between the TCP and BPF versions. Ideally this should never happen.
3451 * If it does, we need to add code to convert them before calling
3452 * the BPF sock_ops function.
3455 BPF_TCP_ESTABLISHED = 1,
3465 BPF_TCP_CLOSING, /* Now a valid state */
3466 BPF_TCP_NEW_SYN_RECV,
3468 BPF_TCP_MAX_STATES /* Leave at the end! */
3471 #define TCP_BPF_IW 1001 /* Set TCP initial congestion window */
3472 #define TCP_BPF_SNDCWND_CLAMP 1002 /* Set sndcwnd_clamp */
3474 struct bpf_perf_event_value {
3480 #define BPF_DEVCG_ACC_MKNOD (1ULL << 0)
3481 #define BPF_DEVCG_ACC_READ (1ULL << 1)
3482 #define BPF_DEVCG_ACC_WRITE (1ULL << 2)
3484 #define BPF_DEVCG_DEV_BLOCK (1ULL << 0)
3485 #define BPF_DEVCG_DEV_CHAR (1ULL << 1)
3487 struct bpf_cgroup_dev_ctx {
3488 /* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
3494 struct bpf_raw_tracepoint_args {
3498 /* DIRECT: Skip the FIB rules and go to FIB table associated with device
3499 * OUTPUT: Do lookup from egress perspective; default is ingress
3501 #define BPF_FIB_LOOKUP_DIRECT (1U << 0)
3502 #define BPF_FIB_LOOKUP_OUTPUT (1U << 1)
3505 BPF_FIB_LKUP_RET_SUCCESS, /* lookup successful */
3506 BPF_FIB_LKUP_RET_BLACKHOLE, /* dest is blackholed; can be dropped */
3507 BPF_FIB_LKUP_RET_UNREACHABLE, /* dest is unreachable; can be dropped */
3508 BPF_FIB_LKUP_RET_PROHIBIT, /* dest not allowed; can be dropped */
3509 BPF_FIB_LKUP_RET_NOT_FWDED, /* packet is not forwarded */
3510 BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
3511 BPF_FIB_LKUP_RET_UNSUPP_LWT, /* fwd requires encapsulation */
3512 BPF_FIB_LKUP_RET_NO_NEIGH, /* no neighbor entry for nh */
3513 BPF_FIB_LKUP_RET_FRAG_NEEDED, /* fragmentation required to fwd */
3516 struct bpf_fib_lookup {
3517 /* input: network family for lookup (AF_INET, AF_INET6)
3518 * output: network family of egress nexthop
3522 /* set if lookup is to consider L4 data - e.g., FIB rules */
3527 /* total length of packet from network header - used for MTU check */
3530 /* input: L3 device index for lookup
3531 * output: device index from FIB lookup
3536 /* inputs to lookup */
3537 __u8 tos; /* AF_INET */
3538 __be32 flowinfo; /* AF_INET6, flow_label + priority */
3540 /* output: metric of fib result (IPv4/IPv6 only) */
3546 __u32 ipv6_src[4]; /* in6_addr; network order */
3549 /* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
3550 * network header. output: bpf_fib_lookup sets to gateway address
3551 * if FIB lookup returns gateway route
3555 __u32 ipv6_dst[4]; /* in6_addr; network order */
3559 __be16 h_vlan_proto;
3561 __u8 smac[6]; /* ETH_ALEN */
3562 __u8 dmac[6]; /* ETH_ALEN */
3565 enum bpf_task_fd_type {
3566 BPF_FD_TYPE_RAW_TRACEPOINT, /* tp name */
3567 BPF_FD_TYPE_TRACEPOINT, /* tp name */
3568 BPF_FD_TYPE_KPROBE, /* (symbol + offset) or addr */
3569 BPF_FD_TYPE_KRETPROBE, /* (symbol + offset) or addr */
3570 BPF_FD_TYPE_UPROBE, /* filename + offset */
3571 BPF_FD_TYPE_URETPROBE, /* filename + offset */
3574 #define BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG (1U << 0)
3575 #define BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL (1U << 1)
3576 #define BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP (1U << 2)
3578 struct bpf_flow_keys {
3581 __u16 addr_proto; /* ETH_P_* of valid addrs */
3595 __u32 ipv6_src[4]; /* in6_addr; network order */
3596 __u32 ipv6_dst[4]; /* in6_addr; network order */
3603 struct bpf_func_info {
3608 #define BPF_LINE_INFO_LINE_NUM(line_col) ((line_col) >> 10)
3609 #define BPF_LINE_INFO_LINE_COL(line_col) ((line_col) & 0x3ff)
3611 struct bpf_line_info {
3613 __u32 file_name_off;
3618 struct bpf_spin_lock {
3623 __u32 write; /* Sysctl is being read (= 0) or written (= 1).
3624 * Allows 1,2,4-byte read, but no write.
3626 __u32 file_pos; /* Sysctl file position to read from, write to.
3627 * Allows 1,2,4-byte read an 4-byte write.
3631 struct bpf_sockopt {
3632 __bpf_md_ptr(struct bpf_sock *, sk);
3633 __bpf_md_ptr(void *, optval);
3634 __bpf_md_ptr(void *, optval_end);
3642 #endif /* _UAPI__LINUX_BPF_H__ */