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_ATOMIC 0xc0 /* atomic memory ops - op type in immediate */
23 #define BPF_XADD 0xc0 /* exclusive add - legacy name */
26 #define BPF_MOV 0xb0 /* mov reg to reg */
27 #define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */
29 /* change endianness of a register */
30 #define BPF_END 0xd0 /* flags for endianness conversion: */
31 #define BPF_TO_LE 0x00 /* convert to little-endian */
32 #define BPF_TO_BE 0x08 /* convert to big-endian */
33 #define BPF_FROM_LE BPF_TO_LE
34 #define BPF_FROM_BE BPF_TO_BE
37 #define BPF_JNE 0x50 /* jump != */
38 #define BPF_JLT 0xa0 /* LT is unsigned, '<' */
39 #define BPF_JLE 0xb0 /* LE is unsigned, '<=' */
40 #define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */
41 #define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */
42 #define BPF_JSLT 0xc0 /* SLT is signed, '<' */
43 #define BPF_JSLE 0xd0 /* SLE is signed, '<=' */
44 #define BPF_CALL 0x80 /* function call */
45 #define BPF_EXIT 0x90 /* function return */
47 /* atomic op type fields (stored in immediate) */
48 #define BPF_FETCH 0x01 /* not an opcode on its own, used to build others */
49 #define BPF_XCHG (0xe0 | BPF_FETCH) /* atomic exchange */
50 #define BPF_CMPXCHG (0xf0 | BPF_FETCH) /* atomic compare-and-write */
52 /* Register numbers */
68 /* BPF has 10 general purpose 64-bit registers and stack frame. */
69 #define MAX_BPF_REG __MAX_BPF_REG
72 __u8 code; /* opcode */
73 __u8 dst_reg:4; /* dest register */
74 __u8 src_reg:4; /* source register */
75 __s16 off; /* signed offset */
76 __s32 imm; /* signed immediate constant */
79 /* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
80 struct bpf_lpm_trie_key {
81 __u32 prefixlen; /* up to 32 for AF_INET, 128 for AF_INET6 */
82 __u8 data[0]; /* Arbitrary size */
85 struct bpf_cgroup_storage_key {
86 __u64 cgroup_inode_id; /* cgroup inode id */
87 __u32 attach_type; /* program attach type (enum bpf_attach_type) */
90 union bpf_iter_link_info {
96 /* BPF syscall commands, see bpf(2) man-page for more details. */
98 * DOC: eBPF Syscall Preamble
100 * The operation to be performed by the **bpf**\ () system call is determined
101 * by the *cmd* argument. Each operation takes an accompanying argument,
102 * provided via *attr*, which is a pointer to a union of type *bpf_attr* (see
103 * below). The size argument is the size of the union pointed to by *attr*.
106 * DOC: eBPF Syscall Commands
110 * Create a map and return a file descriptor that refers to the
111 * map. The close-on-exec file descriptor flag (see **fcntl**\ (2))
112 * is automatically enabled for the new file descriptor.
114 * Applying **close**\ (2) to the file descriptor returned by
115 * **BPF_MAP_CREATE** will delete the map (but see NOTES).
118 * A new file descriptor (a nonnegative integer), or -1 if an
119 * error occurred (in which case, *errno* is set appropriately).
121 * BPF_MAP_LOOKUP_ELEM
123 * Look up an element with a given *key* in the map referred to
124 * by the file descriptor *map_fd*.
126 * The *flags* argument may be specified as one of the
130 * Look up the value of a spin-locked map without
131 * returning the lock. This must be specified if the
132 * elements contain a spinlock.
135 * Returns zero on success. On error, -1 is returned and *errno*
136 * is set appropriately.
138 * BPF_MAP_UPDATE_ELEM
140 * Create or update an element (key/value pair) in a specified map.
142 * The *flags* argument should be specified as one of the
146 * Create a new element or update an existing element.
148 * Create a new element only if it did not exist.
150 * Update an existing element.
152 * Update a spin_lock-ed map element.
155 * Returns zero on success. On error, -1 is returned and *errno*
156 * is set appropriately.
158 * May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**,
159 * **E2BIG**, **EEXIST**, or **ENOENT**.
162 * The number of elements in the map reached the
163 * *max_entries* limit specified at map creation time.
165 * If *flags* specifies **BPF_NOEXIST** and the element
166 * with *key* already exists in the map.
168 * If *flags* specifies **BPF_EXIST** and the element with
169 * *key* does not exist in the map.
171 * BPF_MAP_DELETE_ELEM
173 * Look up and delete an element by key in a specified map.
176 * Returns zero on success. On error, -1 is returned and *errno*
177 * is set appropriately.
179 * BPF_MAP_GET_NEXT_KEY
181 * Look up an element by key in a specified map and return the key
182 * of the next element. Can be used to iterate over all elements
186 * Returns zero on success. On error, -1 is returned and *errno*
187 * is set appropriately.
189 * The following cases can be used to iterate over all elements of
192 * * If *key* is not found, the operation returns zero and sets
193 * the *next_key* pointer to the key of the first element.
194 * * If *key* is found, the operation returns zero and sets the
195 * *next_key* pointer to the key of the next element.
196 * * If *key* is the last element, returns -1 and *errno* is set
199 * May set *errno* to **ENOMEM**, **EFAULT**, **EPERM**, or
200 * **EINVAL** on error.
204 * Verify and load an eBPF program, returning a new file
205 * descriptor associated with the program.
207 * Applying **close**\ (2) to the file descriptor returned by
208 * **BPF_PROG_LOAD** will unload the eBPF program (but see NOTES).
210 * The close-on-exec file descriptor flag (see **fcntl**\ (2)) is
211 * automatically enabled for the new file descriptor.
214 * A new file descriptor (a nonnegative integer), or -1 if an
215 * error occurred (in which case, *errno* is set appropriately).
219 * Pin an eBPF program or map referred by the specified *bpf_fd*
220 * to the provided *pathname* on the filesystem.
222 * The *pathname* argument must not contain a dot (".").
224 * On success, *pathname* retains a reference to the eBPF object,
225 * preventing deallocation of the object when the original
226 * *bpf_fd* is closed. This allow the eBPF object to live beyond
227 * **close**\ (\ *bpf_fd*\ ), and hence the lifetime of the parent
230 * Applying **unlink**\ (2) or similar calls to the *pathname*
231 * unpins the object from the filesystem, removing the reference.
232 * If no other file descriptors or filesystem nodes refer to the
233 * same object, it will be deallocated (see NOTES).
235 * The filesystem type for the parent directory of *pathname* must
236 * be **BPF_FS_MAGIC**.
239 * Returns zero on success. On error, -1 is returned and *errno*
240 * is set appropriately.
244 * Open a file descriptor for the eBPF object pinned to the
245 * specified *pathname*.
248 * A new file descriptor (a nonnegative integer), or -1 if an
249 * error occurred (in which case, *errno* is set appropriately).
253 * Attach an eBPF program to a *target_fd* at the specified
254 * *attach_type* hook.
256 * The *attach_type* specifies the eBPF attachment point to
257 * attach the program to, and must be one of *bpf_attach_type*
260 * The *attach_bpf_fd* must be a valid file descriptor for a
261 * loaded eBPF program of a cgroup, flow dissector, LIRC, sockmap
262 * or sock_ops type corresponding to the specified *attach_type*.
264 * The *target_fd* must be a valid file descriptor for a kernel
265 * object which depends on the attach type of *attach_bpf_fd*:
267 * **BPF_PROG_TYPE_CGROUP_DEVICE**,
268 * **BPF_PROG_TYPE_CGROUP_SKB**,
269 * **BPF_PROG_TYPE_CGROUP_SOCK**,
270 * **BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
271 * **BPF_PROG_TYPE_CGROUP_SOCKOPT**,
272 * **BPF_PROG_TYPE_CGROUP_SYSCTL**,
273 * **BPF_PROG_TYPE_SOCK_OPS**
275 * Control Group v2 hierarchy with the eBPF controller
276 * enabled. Requires the kernel to be compiled with
277 * **CONFIG_CGROUP_BPF**.
279 * **BPF_PROG_TYPE_FLOW_DISSECTOR**
281 * Network namespace (eg /proc/self/ns/net).
283 * **BPF_PROG_TYPE_LIRC_MODE2**
285 * LIRC device path (eg /dev/lircN). Requires the kernel
286 * to be compiled with **CONFIG_BPF_LIRC_MODE2**.
288 * **BPF_PROG_TYPE_SK_SKB**,
289 * **BPF_PROG_TYPE_SK_MSG**
291 * eBPF map of socket type (eg **BPF_MAP_TYPE_SOCKHASH**).
294 * Returns zero on success. On error, -1 is returned and *errno*
295 * is set appropriately.
299 * Detach the eBPF program associated with the *target_fd* at the
300 * hook specified by *attach_type*. The program must have been
301 * previously attached using **BPF_PROG_ATTACH**.
304 * Returns zero on success. On error, -1 is returned and *errno*
305 * is set appropriately.
309 * Run the eBPF program associated with the *prog_fd* a *repeat*
310 * number of times against a provided program context *ctx_in* and
311 * data *data_in*, and return the modified program context
312 * *ctx_out*, *data_out* (for example, packet data), result of the
313 * execution *retval*, and *duration* of the test run.
315 * The sizes of the buffers provided as input and output
316 * parameters *ctx_in*, *ctx_out*, *data_in*, and *data_out* must
317 * be provided in the corresponding variables *ctx_size_in*,
318 * *ctx_size_out*, *data_size_in*, and/or *data_size_out*. If any
319 * of these parameters are not provided (ie set to NULL), the
320 * corresponding size field must be zero.
322 * Some program types have particular requirements:
324 * **BPF_PROG_TYPE_SK_LOOKUP**
325 * *data_in* and *data_out* must be NULL.
327 * **BPF_PROG_TYPE_RAW_TRACEPOINT**,
328 * **BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE**
330 * *ctx_out*, *data_in* and *data_out* must be NULL.
331 * *repeat* must be zero.
334 * Returns zero on success. On error, -1 is returned and *errno*
335 * is set appropriately.
338 * Either *data_size_out* or *ctx_size_out* is too small.
340 * This command is not supported by the program type of
341 * the program referred to by *prog_fd*.
343 * BPF_PROG_GET_NEXT_ID
345 * Fetch the next eBPF program currently loaded into the kernel.
347 * Looks for the eBPF program with an id greater than *start_id*
348 * and updates *next_id* on success. If no other eBPF programs
349 * remain with ids higher than *start_id*, returns -1 and sets
350 * *errno* to **ENOENT**.
353 * Returns zero on success. On error, or when no id remains, -1
354 * is returned and *errno* is set appropriately.
356 * BPF_MAP_GET_NEXT_ID
358 * Fetch the next eBPF map currently loaded into the kernel.
360 * Looks for the eBPF map with an id greater than *start_id*
361 * and updates *next_id* on success. If no other eBPF maps
362 * remain with ids higher than *start_id*, returns -1 and sets
363 * *errno* to **ENOENT**.
366 * Returns zero on success. On error, or when no id remains, -1
367 * is returned and *errno* is set appropriately.
369 * BPF_PROG_GET_FD_BY_ID
371 * Open a file descriptor for the eBPF program corresponding to
375 * A new file descriptor (a nonnegative integer), or -1 if an
376 * error occurred (in which case, *errno* is set appropriately).
378 * BPF_MAP_GET_FD_BY_ID
380 * Open a file descriptor for the eBPF map corresponding to
384 * A new file descriptor (a nonnegative integer), or -1 if an
385 * error occurred (in which case, *errno* is set appropriately).
387 * BPF_OBJ_GET_INFO_BY_FD
389 * Obtain information about the eBPF object corresponding to
392 * Populates up to *info_len* bytes of *info*, which will be in
393 * one of the following formats depending on the eBPF object type
396 * * **struct bpf_prog_info**
397 * * **struct bpf_map_info**
398 * * **struct bpf_btf_info**
399 * * **struct bpf_link_info**
402 * Returns zero on success. On error, -1 is returned and *errno*
403 * is set appropriately.
407 * Obtain information about eBPF programs associated with the
408 * specified *attach_type* hook.
410 * The *target_fd* must be a valid file descriptor for a kernel
411 * object which depends on the attach type of *attach_bpf_fd*:
413 * **BPF_PROG_TYPE_CGROUP_DEVICE**,
414 * **BPF_PROG_TYPE_CGROUP_SKB**,
415 * **BPF_PROG_TYPE_CGROUP_SOCK**,
416 * **BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
417 * **BPF_PROG_TYPE_CGROUP_SOCKOPT**,
418 * **BPF_PROG_TYPE_CGROUP_SYSCTL**,
419 * **BPF_PROG_TYPE_SOCK_OPS**
421 * Control Group v2 hierarchy with the eBPF controller
422 * enabled. Requires the kernel to be compiled with
423 * **CONFIG_CGROUP_BPF**.
425 * **BPF_PROG_TYPE_FLOW_DISSECTOR**
427 * Network namespace (eg /proc/self/ns/net).
429 * **BPF_PROG_TYPE_LIRC_MODE2**
431 * LIRC device path (eg /dev/lircN). Requires the kernel
432 * to be compiled with **CONFIG_BPF_LIRC_MODE2**.
434 * **BPF_PROG_QUERY** always fetches the number of programs
435 * attached and the *attach_flags* which were used to attach those
436 * programs. Additionally, if *prog_ids* is nonzero and the number
437 * of attached programs is less than *prog_cnt*, populates
438 * *prog_ids* with the eBPF program ids of the programs attached
441 * The following flags may alter the result:
443 * **BPF_F_QUERY_EFFECTIVE**
444 * Only return information regarding programs which are
445 * currently effective at the specified *target_fd*.
448 * Returns zero on success. On error, -1 is returned and *errno*
449 * is set appropriately.
451 * BPF_RAW_TRACEPOINT_OPEN
453 * Attach an eBPF program to a tracepoint *name* to access kernel
454 * internal arguments of the tracepoint in their raw form.
456 * The *prog_fd* must be a valid file descriptor associated with
457 * a loaded eBPF program of type **BPF_PROG_TYPE_RAW_TRACEPOINT**.
459 * No ABI guarantees are made about the content of tracepoint
460 * arguments exposed to the corresponding eBPF program.
462 * Applying **close**\ (2) to the file descriptor returned by
463 * **BPF_RAW_TRACEPOINT_OPEN** will delete the map (but see NOTES).
466 * A new file descriptor (a nonnegative integer), or -1 if an
467 * error occurred (in which case, *errno* is set appropriately).
471 * Verify and load BPF Type Format (BTF) metadata into the kernel,
472 * returning a new file descriptor associated with the metadata.
473 * BTF is described in more detail at
474 * https://www.kernel.org/doc/html/latest/bpf/btf.html.
476 * The *btf* parameter must point to valid memory providing
477 * *btf_size* bytes of BTF binary metadata.
479 * The returned file descriptor can be passed to other **bpf**\ ()
480 * subcommands such as **BPF_PROG_LOAD** or **BPF_MAP_CREATE** to
481 * associate the BTF with those objects.
483 * Similar to **BPF_PROG_LOAD**, **BPF_BTF_LOAD** has optional
484 * parameters to specify a *btf_log_buf*, *btf_log_size* and
485 * *btf_log_level* which allow the kernel to return freeform log
486 * output regarding the BTF verification process.
489 * A new file descriptor (a nonnegative integer), or -1 if an
490 * error occurred (in which case, *errno* is set appropriately).
492 * BPF_BTF_GET_FD_BY_ID
494 * Open a file descriptor for the BPF Type Format (BTF)
495 * corresponding to *btf_id*.
498 * A new file descriptor (a nonnegative integer), or -1 if an
499 * error occurred (in which case, *errno* is set appropriately).
503 * Obtain information about eBPF programs associated with the
504 * target process identified by *pid* and *fd*.
506 * If the *pid* and *fd* are associated with a tracepoint, kprobe
507 * or uprobe perf event, then the *prog_id* and *fd_type* will
508 * be populated with the eBPF program id and file descriptor type
509 * of type **bpf_task_fd_type**. If associated with a kprobe or
510 * uprobe, the *probe_offset* and *probe_addr* will also be
511 * populated. Optionally, if *buf* is provided, then up to
512 * *buf_len* bytes of *buf* will be populated with the name of
513 * the tracepoint, kprobe or uprobe.
515 * The resulting *prog_id* may be introspected in deeper detail
516 * using **BPF_PROG_GET_FD_BY_ID** and **BPF_OBJ_GET_INFO_BY_FD**.
519 * Returns zero on success. On error, -1 is returned and *errno*
520 * is set appropriately.
522 * BPF_MAP_LOOKUP_AND_DELETE_ELEM
524 * Look up an element with the given *key* in the map referred to
525 * by the file descriptor *fd*, and if found, delete the element.
527 * For **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map
528 * types, the *flags* argument needs to be set to 0, but for other
529 * map types, it may be specified as:
532 * Look up and delete the value of a spin-locked map
533 * without returning the lock. This must be specified if
534 * the elements contain a spinlock.
536 * The **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map types
537 * implement this command as a "pop" operation, deleting the top
538 * element rather than one corresponding to *key*.
539 * The *key* and *key_len* parameters should be zeroed when
540 * issuing this operation for these map types.
542 * This command is only valid for the following map types:
543 * * **BPF_MAP_TYPE_QUEUE**
544 * * **BPF_MAP_TYPE_STACK**
545 * * **BPF_MAP_TYPE_HASH**
546 * * **BPF_MAP_TYPE_PERCPU_HASH**
547 * * **BPF_MAP_TYPE_LRU_HASH**
548 * * **BPF_MAP_TYPE_LRU_PERCPU_HASH**
551 * Returns zero on success. On error, -1 is returned and *errno*
552 * is set appropriately.
556 * Freeze the permissions of the specified map.
558 * Write permissions may be frozen by passing zero *flags*.
559 * Upon success, no future syscall invocations may alter the
560 * map state of *map_fd*. Write operations from eBPF programs
561 * are still possible for a frozen map.
563 * Not supported for maps of type **BPF_MAP_TYPE_STRUCT_OPS**.
566 * Returns zero on success. On error, -1 is returned and *errno*
567 * is set appropriately.
569 * BPF_BTF_GET_NEXT_ID
571 * Fetch the next BPF Type Format (BTF) object currently loaded
574 * Looks for the BTF object with an id greater than *start_id*
575 * and updates *next_id* on success. If no other BTF objects
576 * remain with ids higher than *start_id*, returns -1 and sets
577 * *errno* to **ENOENT**.
580 * Returns zero on success. On error, or when no id remains, -1
581 * is returned and *errno* is set appropriately.
583 * BPF_MAP_LOOKUP_BATCH
585 * Iterate and fetch multiple elements in a map.
587 * Two opaque values are used to manage batch operations,
588 * *in_batch* and *out_batch*. Initially, *in_batch* must be set
589 * to NULL to begin the batched operation. After each subsequent
590 * **BPF_MAP_LOOKUP_BATCH**, the caller should pass the resultant
591 * *out_batch* as the *in_batch* for the next operation to
592 * continue iteration from the current point.
594 * The *keys* and *values* are output parameters which must point
595 * to memory large enough to hold *count* items based on the key
596 * and value size of the map *map_fd*. The *keys* buffer must be
597 * of *key_size* * *count*. The *values* buffer must be of
598 * *value_size* * *count*.
600 * The *elem_flags* argument may be specified as one of the
604 * Look up the value of a spin-locked map without
605 * returning the lock. This must be specified if the
606 * elements contain a spinlock.
608 * On success, *count* elements from the map are copied into the
609 * user buffer, with the keys copied into *keys* and the values
610 * copied into the corresponding indices in *values*.
612 * If an error is returned and *errno* is not **EFAULT**, *count*
613 * is set to the number of successfully processed elements.
616 * Returns zero on success. On error, -1 is returned and *errno*
617 * is set appropriately.
619 * May set *errno* to **ENOSPC** to indicate that *keys* or
620 * *values* is too small to dump an entire bucket during
621 * iteration of a hash-based map type.
623 * BPF_MAP_LOOKUP_AND_DELETE_BATCH
625 * Iterate and delete all elements in a map.
627 * This operation has the same behavior as
628 * **BPF_MAP_LOOKUP_BATCH** with two exceptions:
630 * * Every element that is successfully returned is also deleted
631 * from the map. This is at least *count* elements. Note that
632 * *count* is both an input and an output parameter.
633 * * Upon returning with *errno* set to **EFAULT**, up to
634 * *count* elements may be deleted without returning the keys
635 * and values of the deleted elements.
638 * Returns zero on success. On error, -1 is returned and *errno*
639 * is set appropriately.
641 * BPF_MAP_UPDATE_BATCH
643 * Update multiple elements in a map by *key*.
645 * The *keys* and *values* are input parameters which must point
646 * to memory large enough to hold *count* items based on the key
647 * and value size of the map *map_fd*. The *keys* buffer must be
648 * of *key_size* * *count*. The *values* buffer must be of
649 * *value_size* * *count*.
651 * Each element specified in *keys* is sequentially updated to the
652 * value in the corresponding index in *values*. The *in_batch*
653 * and *out_batch* parameters are ignored and should be zeroed.
655 * The *elem_flags* argument should be specified as one of the
659 * Create new elements or update a existing elements.
661 * Create new elements only if they do not exist.
663 * Update existing elements.
665 * Update spin_lock-ed map elements. This must be
666 * specified if the map value contains a spinlock.
668 * On success, *count* elements from the map are updated.
670 * If an error is returned and *errno* is not **EFAULT**, *count*
671 * is set to the number of successfully processed elements.
674 * Returns zero on success. On error, -1 is returned and *errno*
675 * is set appropriately.
677 * May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**, or
678 * **E2BIG**. **E2BIG** indicates that the number of elements in
679 * the map reached the *max_entries* limit specified at map
682 * May set *errno* to one of the following error codes under
683 * specific circumstances:
686 * If *flags* specifies **BPF_NOEXIST** and the element
687 * with *key* already exists in the map.
689 * If *flags* specifies **BPF_EXIST** and the element with
690 * *key* does not exist in the map.
692 * BPF_MAP_DELETE_BATCH
694 * Delete multiple elements in a map by *key*.
696 * The *keys* parameter is an input parameter which must point
697 * to memory large enough to hold *count* items based on the key
698 * size of the map *map_fd*, that is, *key_size* * *count*.
700 * Each element specified in *keys* is sequentially deleted. The
701 * *in_batch*, *out_batch*, and *values* parameters are ignored
702 * and should be zeroed.
704 * The *elem_flags* argument may be specified as one of the
708 * Look up the value of a spin-locked map without
709 * returning the lock. This must be specified if the
710 * elements contain a spinlock.
712 * On success, *count* elements from the map are updated.
714 * If an error is returned and *errno* is not **EFAULT**, *count*
715 * is set to the number of successfully processed elements. If
716 * *errno* is **EFAULT**, up to *count* elements may be been
720 * Returns zero on success. On error, -1 is returned and *errno*
721 * is set appropriately.
725 * Attach an eBPF program to a *target_fd* at the specified
726 * *attach_type* hook and return a file descriptor handle for
730 * A new file descriptor (a nonnegative integer), or -1 if an
731 * error occurred (in which case, *errno* is set appropriately).
735 * Update the eBPF program in the specified *link_fd* to
739 * Returns zero on success. On error, -1 is returned and *errno*
740 * is set appropriately.
742 * BPF_LINK_GET_FD_BY_ID
744 * Open a file descriptor for the eBPF Link corresponding to
748 * A new file descriptor (a nonnegative integer), or -1 if an
749 * error occurred (in which case, *errno* is set appropriately).
751 * BPF_LINK_GET_NEXT_ID
753 * Fetch the next eBPF link currently loaded into the kernel.
755 * Looks for the eBPF link with an id greater than *start_id*
756 * and updates *next_id* on success. If no other eBPF links
757 * remain with ids higher than *start_id*, returns -1 and sets
758 * *errno* to **ENOENT**.
761 * Returns zero on success. On error, or when no id remains, -1
762 * is returned and *errno* is set appropriately.
766 * Enable eBPF runtime statistics gathering.
768 * Runtime statistics gathering for the eBPF runtime is disabled
769 * by default to minimize the corresponding performance overhead.
770 * This command enables statistics globally.
772 * Multiple programs may independently enable statistics.
773 * After gathering the desired statistics, eBPF runtime statistics
774 * may be disabled again by calling **close**\ (2) for the file
775 * descriptor returned by this function. Statistics will only be
776 * disabled system-wide when all outstanding file descriptors
777 * returned by prior calls for this subcommand are closed.
780 * A new file descriptor (a nonnegative integer), or -1 if an
781 * error occurred (in which case, *errno* is set appropriately).
785 * Create an iterator on top of the specified *link_fd* (as
786 * previously created using **BPF_LINK_CREATE**) and return a
787 * file descriptor that can be used to trigger the iteration.
789 * If the resulting file descriptor is pinned to the filesystem
790 * using **BPF_OBJ_PIN**, then subsequent **read**\ (2) syscalls
791 * for that path will trigger the iterator to read kernel state
792 * using the eBPF program attached to *link_fd*.
795 * A new file descriptor (a nonnegative integer), or -1 if an
796 * error occurred (in which case, *errno* is set appropriately).
800 * Forcefully detach the specified *link_fd* from its
801 * corresponding attachment point.
804 * Returns zero on success. On error, -1 is returned and *errno*
805 * is set appropriately.
809 * Bind a map to the lifetime of an eBPF program.
811 * The map identified by *map_fd* is bound to the program
812 * identified by *prog_fd* and only released when *prog_fd* is
813 * released. This may be used in cases where metadata should be
814 * associated with a program which otherwise does not contain any
815 * references to the map (for example, embedded in the eBPF
816 * program instructions).
819 * Returns zero on success. On error, -1 is returned and *errno*
820 * is set appropriately.
823 * eBPF objects (maps and programs) can be shared between processes.
825 * * After **fork**\ (2), the child inherits file descriptors
826 * referring to the same eBPF objects.
827 * * File descriptors referring to eBPF objects can be transferred over
828 * **unix**\ (7) domain sockets.
829 * * File descriptors referring to eBPF objects can be duplicated in the
830 * usual way, using **dup**\ (2) and similar calls.
831 * * File descriptors referring to eBPF objects can be pinned to the
832 * filesystem using the **BPF_OBJ_PIN** command of **bpf**\ (2).
834 * An eBPF object is deallocated only after all file descriptors referring
835 * to the object have been closed and no references remain pinned to the
836 * filesystem or attached (for example, bound to a program or device).
843 BPF_MAP_GET_NEXT_KEY,
850 BPF_PROG_RUN = BPF_PROG_TEST_RUN,
851 BPF_PROG_GET_NEXT_ID,
853 BPF_PROG_GET_FD_BY_ID,
854 BPF_MAP_GET_FD_BY_ID,
855 BPF_OBJ_GET_INFO_BY_FD,
857 BPF_RAW_TRACEPOINT_OPEN,
859 BPF_BTF_GET_FD_BY_ID,
861 BPF_MAP_LOOKUP_AND_DELETE_ELEM,
864 BPF_MAP_LOOKUP_BATCH,
865 BPF_MAP_LOOKUP_AND_DELETE_BATCH,
866 BPF_MAP_UPDATE_BATCH,
867 BPF_MAP_DELETE_BATCH,
870 BPF_LINK_GET_FD_BY_ID,
871 BPF_LINK_GET_NEXT_ID,
882 BPF_MAP_TYPE_PROG_ARRAY,
883 BPF_MAP_TYPE_PERF_EVENT_ARRAY,
884 BPF_MAP_TYPE_PERCPU_HASH,
885 BPF_MAP_TYPE_PERCPU_ARRAY,
886 BPF_MAP_TYPE_STACK_TRACE,
887 BPF_MAP_TYPE_CGROUP_ARRAY,
888 BPF_MAP_TYPE_LRU_HASH,
889 BPF_MAP_TYPE_LRU_PERCPU_HASH,
890 BPF_MAP_TYPE_LPM_TRIE,
891 BPF_MAP_TYPE_ARRAY_OF_MAPS,
892 BPF_MAP_TYPE_HASH_OF_MAPS,
894 BPF_MAP_TYPE_SOCKMAP,
897 BPF_MAP_TYPE_SOCKHASH,
898 BPF_MAP_TYPE_CGROUP_STORAGE,
899 BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
900 BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE,
903 BPF_MAP_TYPE_SK_STORAGE,
904 BPF_MAP_TYPE_DEVMAP_HASH,
905 BPF_MAP_TYPE_STRUCT_OPS,
906 BPF_MAP_TYPE_RINGBUF,
907 BPF_MAP_TYPE_INODE_STORAGE,
908 BPF_MAP_TYPE_TASK_STORAGE,
909 BPF_MAP_TYPE_BLOOM_FILTER,
912 /* Note that tracing related programs such as
913 * BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
914 * are not subject to a stable API since kernel internal data
915 * structures can change from release to release and may
916 * therefore break existing tracing BPF programs. Tracing BPF
917 * programs correspond to /a/ specific kernel which is to be
918 * analyzed, and not /a/ specific kernel /and/ all future ones.
921 BPF_PROG_TYPE_UNSPEC,
922 BPF_PROG_TYPE_SOCKET_FILTER,
923 BPF_PROG_TYPE_KPROBE,
924 BPF_PROG_TYPE_SCHED_CLS,
925 BPF_PROG_TYPE_SCHED_ACT,
926 BPF_PROG_TYPE_TRACEPOINT,
928 BPF_PROG_TYPE_PERF_EVENT,
929 BPF_PROG_TYPE_CGROUP_SKB,
930 BPF_PROG_TYPE_CGROUP_SOCK,
931 BPF_PROG_TYPE_LWT_IN,
932 BPF_PROG_TYPE_LWT_OUT,
933 BPF_PROG_TYPE_LWT_XMIT,
934 BPF_PROG_TYPE_SOCK_OPS,
935 BPF_PROG_TYPE_SK_SKB,
936 BPF_PROG_TYPE_CGROUP_DEVICE,
937 BPF_PROG_TYPE_SK_MSG,
938 BPF_PROG_TYPE_RAW_TRACEPOINT,
939 BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
940 BPF_PROG_TYPE_LWT_SEG6LOCAL,
941 BPF_PROG_TYPE_LIRC_MODE2,
942 BPF_PROG_TYPE_SK_REUSEPORT,
943 BPF_PROG_TYPE_FLOW_DISSECTOR,
944 BPF_PROG_TYPE_CGROUP_SYSCTL,
945 BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
946 BPF_PROG_TYPE_CGROUP_SOCKOPT,
947 BPF_PROG_TYPE_TRACING,
948 BPF_PROG_TYPE_STRUCT_OPS,
951 BPF_PROG_TYPE_SK_LOOKUP,
952 BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */
955 enum bpf_attach_type {
956 BPF_CGROUP_INET_INGRESS,
957 BPF_CGROUP_INET_EGRESS,
958 BPF_CGROUP_INET_SOCK_CREATE,
960 BPF_SK_SKB_STREAM_PARSER,
961 BPF_SK_SKB_STREAM_VERDICT,
964 BPF_CGROUP_INET4_BIND,
965 BPF_CGROUP_INET6_BIND,
966 BPF_CGROUP_INET4_CONNECT,
967 BPF_CGROUP_INET6_CONNECT,
968 BPF_CGROUP_INET4_POST_BIND,
969 BPF_CGROUP_INET6_POST_BIND,
970 BPF_CGROUP_UDP4_SENDMSG,
971 BPF_CGROUP_UDP6_SENDMSG,
975 BPF_CGROUP_UDP4_RECVMSG,
976 BPF_CGROUP_UDP6_RECVMSG,
977 BPF_CGROUP_GETSOCKOPT,
978 BPF_CGROUP_SETSOCKOPT,
985 BPF_CGROUP_INET4_GETPEERNAME,
986 BPF_CGROUP_INET6_GETPEERNAME,
987 BPF_CGROUP_INET4_GETSOCKNAME,
988 BPF_CGROUP_INET6_GETSOCKNAME,
990 BPF_CGROUP_INET_SOCK_RELEASE,
995 BPF_SK_REUSEPORT_SELECT,
996 BPF_SK_REUSEPORT_SELECT_OR_MIGRATE,
998 __MAX_BPF_ATTACH_TYPE
1001 #define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
1003 enum bpf_link_type {
1004 BPF_LINK_TYPE_UNSPEC = 0,
1005 BPF_LINK_TYPE_RAW_TRACEPOINT = 1,
1006 BPF_LINK_TYPE_TRACING = 2,
1007 BPF_LINK_TYPE_CGROUP = 3,
1008 BPF_LINK_TYPE_ITER = 4,
1009 BPF_LINK_TYPE_NETNS = 5,
1010 BPF_LINK_TYPE_XDP = 6,
1011 BPF_LINK_TYPE_PERF_EVENT = 7,
1016 /* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
1018 * NONE(default): No further bpf programs allowed in the subtree.
1020 * BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
1021 * the program in this cgroup yields to sub-cgroup program.
1023 * BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
1024 * that cgroup program gets run in addition to the program in this cgroup.
1026 * Only one program is allowed to be attached to a cgroup with
1027 * NONE or BPF_F_ALLOW_OVERRIDE flag.
1028 * Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
1029 * release old program and attach the new one. Attach flags has to match.
1031 * Multiple programs are allowed to be attached to a cgroup with
1032 * BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
1033 * (those that were attached first, run first)
1034 * The programs of sub-cgroup are executed first, then programs of
1035 * this cgroup and then programs of parent cgroup.
1036 * When children program makes decision (like picking TCP CA or sock bind)
1037 * parent program has a chance to override it.
1039 * With BPF_F_ALLOW_MULTI a new program is added to the end of the list of
1040 * programs for a cgroup. Though it's possible to replace an old program at
1041 * any position by also specifying BPF_F_REPLACE flag and position itself in
1042 * replace_bpf_fd attribute. Old program at this position will be released.
1044 * A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
1045 * A cgroup with NONE doesn't allow any programs in sub-cgroups.
1047 * cgrp1 (MULTI progs A, B) ->
1048 * cgrp2 (OVERRIDE prog C) ->
1049 * cgrp3 (MULTI prog D) ->
1050 * cgrp4 (OVERRIDE prog E) ->
1051 * cgrp5 (NONE prog F)
1052 * the event in cgrp5 triggers execution of F,D,A,B in that order.
1053 * if prog F is detached, the execution is E,D,A,B
1054 * if prog F and D are detached, the execution is E,A,B
1055 * if prog F, E and D are detached, the execution is C,A,B
1057 * All eligible programs are executed regardless of return code from
1060 #define BPF_F_ALLOW_OVERRIDE (1U << 0)
1061 #define BPF_F_ALLOW_MULTI (1U << 1)
1062 #define BPF_F_REPLACE (1U << 2)
1064 /* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
1065 * verifier will perform strict alignment checking as if the kernel
1066 * has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
1067 * and NET_IP_ALIGN defined to 2.
1069 #define BPF_F_STRICT_ALIGNMENT (1U << 0)
1071 /* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the
1072 * verifier will allow any alignment whatsoever. On platforms
1073 * with strict alignment requirements for loads ands stores (such
1074 * as sparc and mips) the verifier validates that all loads and
1075 * stores provably follow this requirement. This flag turns that
1076 * checking and enforcement off.
1078 * It is mostly used for testing when we want to validate the
1079 * context and memory access aspects of the verifier, but because
1080 * of an unaligned access the alignment check would trigger before
1081 * the one we are interested in.
1083 #define BPF_F_ANY_ALIGNMENT (1U << 1)
1085 /* BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose.
1086 * Verifier does sub-register def/use analysis and identifies instructions whose
1087 * def only matters for low 32-bit, high 32-bit is never referenced later
1088 * through implicit zero extension. Therefore verifier notifies JIT back-ends
1089 * that it is safe to ignore clearing high 32-bit for these instructions. This
1090 * saves some back-ends a lot of code-gen. However such optimization is not
1091 * necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends
1092 * hence hasn't used verifier's analysis result. But, we really want to have a
1093 * way to be able to verify the correctness of the described optimization on
1094 * x86_64 on which testsuites are frequently exercised.
1096 * So, this flag is introduced. Once it is set, verifier will randomize high
1097 * 32-bit for those instructions who has been identified as safe to ignore them.
1098 * Then, if verifier is not doing correct analysis, such randomization will
1099 * regress tests to expose bugs.
1101 #define BPF_F_TEST_RND_HI32 (1U << 2)
1103 /* The verifier internal test flag. Behavior is undefined */
1104 #define BPF_F_TEST_STATE_FREQ (1U << 3)
1106 /* If BPF_F_SLEEPABLE is used in BPF_PROG_LOAD command, the verifier will
1107 * restrict map and helper usage for such programs. Sleepable BPF programs can
1108 * only be attached to hooks where kernel execution context allows sleeping.
1109 * Such programs are allowed to use helpers that may sleep like
1110 * bpf_copy_from_user().
1112 #define BPF_F_SLEEPABLE (1U << 4)
1114 /* When BPF ldimm64's insn[0].src_reg != 0 then this can have
1115 * the following extensions:
1117 * insn[0].src_reg: BPF_PSEUDO_MAP_[FD|IDX]
1118 * insn[0].imm: map fd or fd_idx
1122 * ldimm64 rewrite: address of map
1123 * verifier type: CONST_PTR_TO_MAP
1125 #define BPF_PSEUDO_MAP_FD 1
1126 #define BPF_PSEUDO_MAP_IDX 5
1128 /* insn[0].src_reg: BPF_PSEUDO_MAP_[IDX_]VALUE
1129 * insn[0].imm: map fd or fd_idx
1130 * insn[1].imm: offset into value
1133 * ldimm64 rewrite: address of map[0]+offset
1134 * verifier type: PTR_TO_MAP_VALUE
1136 #define BPF_PSEUDO_MAP_VALUE 2
1137 #define BPF_PSEUDO_MAP_IDX_VALUE 6
1139 /* insn[0].src_reg: BPF_PSEUDO_BTF_ID
1140 * insn[0].imm: kernel btd id of VAR
1144 * ldimm64 rewrite: address of the kernel variable
1145 * verifier type: PTR_TO_BTF_ID or PTR_TO_MEM, depending on whether the var
1148 #define BPF_PSEUDO_BTF_ID 3
1149 /* insn[0].src_reg: BPF_PSEUDO_FUNC
1150 * insn[0].imm: insn offset to the func
1154 * ldimm64 rewrite: address of the function
1155 * verifier type: PTR_TO_FUNC.
1157 #define BPF_PSEUDO_FUNC 4
1159 /* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
1160 * offset to another bpf function
1162 #define BPF_PSEUDO_CALL 1
1163 /* when bpf_call->src_reg == BPF_PSEUDO_KFUNC_CALL,
1164 * bpf_call->imm == btf_id of a BTF_KIND_FUNC in the running kernel
1166 #define BPF_PSEUDO_KFUNC_CALL 2
1168 /* flags for BPF_MAP_UPDATE_ELEM command */
1170 BPF_ANY = 0, /* create new element or update existing */
1171 BPF_NOEXIST = 1, /* create new element if it didn't exist */
1172 BPF_EXIST = 2, /* update existing element */
1173 BPF_F_LOCK = 4, /* spin_lock-ed map_lookup/map_update */
1176 /* flags for BPF_MAP_CREATE command */
1178 BPF_F_NO_PREALLOC = (1U << 0),
1179 /* Instead of having one common LRU list in the
1180 * BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
1181 * which can scale and perform better.
1182 * Note, the LRU nodes (including free nodes) cannot be moved
1183 * across different LRU lists.
1185 BPF_F_NO_COMMON_LRU = (1U << 1),
1186 /* Specify numa node during map creation */
1187 BPF_F_NUMA_NODE = (1U << 2),
1189 /* Flags for accessing BPF object from syscall side. */
1190 BPF_F_RDONLY = (1U << 3),
1191 BPF_F_WRONLY = (1U << 4),
1193 /* Flag for stack_map, store build_id+offset instead of pointer */
1194 BPF_F_STACK_BUILD_ID = (1U << 5),
1196 /* Zero-initialize hash function seed. This should only be used for testing. */
1197 BPF_F_ZERO_SEED = (1U << 6),
1199 /* Flags for accessing BPF object from program side. */
1200 BPF_F_RDONLY_PROG = (1U << 7),
1201 BPF_F_WRONLY_PROG = (1U << 8),
1203 /* Clone map from listener for newly accepted socket */
1204 BPF_F_CLONE = (1U << 9),
1206 /* Enable memory-mapping BPF map */
1207 BPF_F_MMAPABLE = (1U << 10),
1209 /* Share perf_event among processes */
1210 BPF_F_PRESERVE_ELEMS = (1U << 11),
1212 /* Create a map that is suitable to be an inner map with dynamic max entries */
1213 BPF_F_INNER_MAP = (1U << 12),
1216 /* Flags for BPF_PROG_QUERY. */
1218 /* Query effective (directly attached + inherited from ancestor cgroups)
1219 * programs that will be executed for events within a cgroup.
1220 * attach_flags with this flag are returned only for directly attached programs.
1222 #define BPF_F_QUERY_EFFECTIVE (1U << 0)
1224 /* Flags for BPF_PROG_TEST_RUN */
1226 /* If set, run the test on the cpu specified by bpf_attr.test.cpu */
1227 #define BPF_F_TEST_RUN_ON_CPU (1U << 0)
1229 /* type for BPF_ENABLE_STATS */
1230 enum bpf_stats_type {
1231 /* enabled run_time_ns and run_cnt */
1232 BPF_STATS_RUN_TIME = 0,
1235 enum bpf_stack_build_id_status {
1236 /* user space need an empty entry to identify end of a trace */
1237 BPF_STACK_BUILD_ID_EMPTY = 0,
1238 /* with valid build_id and offset */
1239 BPF_STACK_BUILD_ID_VALID = 1,
1240 /* couldn't get build_id, fallback to ip */
1241 BPF_STACK_BUILD_ID_IP = 2,
1244 #define BPF_BUILD_ID_SIZE 20
1245 struct bpf_stack_build_id {
1247 unsigned char build_id[BPF_BUILD_ID_SIZE];
1254 #define BPF_OBJ_NAME_LEN 16U
1257 struct { /* anonymous struct used by BPF_MAP_CREATE command */
1258 __u32 map_type; /* one of enum bpf_map_type */
1259 __u32 key_size; /* size of key in bytes */
1260 __u32 value_size; /* size of value in bytes */
1261 __u32 max_entries; /* max number of entries in a map */
1262 __u32 map_flags; /* BPF_MAP_CREATE related
1263 * flags defined above.
1265 __u32 inner_map_fd; /* fd pointing to the inner map */
1266 __u32 numa_node; /* numa node (effective only if
1267 * BPF_F_NUMA_NODE is set).
1269 char map_name[BPF_OBJ_NAME_LEN];
1270 __u32 map_ifindex; /* ifindex of netdev to create on */
1271 __u32 btf_fd; /* fd pointing to a BTF type data */
1272 __u32 btf_key_type_id; /* BTF type_id of the key */
1273 __u32 btf_value_type_id; /* BTF type_id of the value */
1274 __u32 btf_vmlinux_value_type_id;/* BTF type_id of a kernel-
1275 * struct stored as the
1278 /* Any per-map-type extra fields
1280 * BPF_MAP_TYPE_BLOOM_FILTER - the lowest 4 bits indicate the
1281 * number of hash functions (if 0, the bloom filter will default
1282 * to using 5 hash functions).
1287 struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
1291 __aligned_u64 value;
1292 __aligned_u64 next_key;
1297 struct { /* struct used by BPF_MAP_*_BATCH commands */
1298 __aligned_u64 in_batch; /* start batch,
1299 * NULL to start from beginning
1301 __aligned_u64 out_batch; /* output: next start batch */
1303 __aligned_u64 values;
1304 __u32 count; /* input/output:
1305 * input: # of key/value
1307 * output: # of filled elements
1314 struct { /* anonymous struct used by BPF_PROG_LOAD command */
1315 __u32 prog_type; /* one of enum bpf_prog_type */
1317 __aligned_u64 insns;
1318 __aligned_u64 license;
1319 __u32 log_level; /* verbosity level of verifier */
1320 __u32 log_size; /* size of user buffer */
1321 __aligned_u64 log_buf; /* user supplied buffer */
1322 __u32 kern_version; /* not used */
1324 char prog_name[BPF_OBJ_NAME_LEN];
1325 __u32 prog_ifindex; /* ifindex of netdev to prep for */
1326 /* For some prog types expected attach type must be known at
1327 * load time to verify attach type specific parts of prog
1328 * (context accesses, allowed helpers, etc).
1330 __u32 expected_attach_type;
1331 __u32 prog_btf_fd; /* fd pointing to BTF type data */
1332 __u32 func_info_rec_size; /* userspace bpf_func_info size */
1333 __aligned_u64 func_info; /* func info */
1334 __u32 func_info_cnt; /* number of bpf_func_info records */
1335 __u32 line_info_rec_size; /* userspace bpf_line_info size */
1336 __aligned_u64 line_info; /* line info */
1337 __u32 line_info_cnt; /* number of bpf_line_info records */
1338 __u32 attach_btf_id; /* in-kernel BTF type id to attach to */
1340 /* valid prog_fd to attach to bpf prog */
1341 __u32 attach_prog_fd;
1342 /* or valid module BTF object fd or 0 to attach to vmlinux */
1343 __u32 attach_btf_obj_fd;
1345 __u32 core_relo_cnt; /* number of bpf_core_relo */
1346 __aligned_u64 fd_array; /* array of FDs */
1347 __aligned_u64 core_relos;
1348 __u32 core_relo_rec_size; /* sizeof(struct bpf_core_relo) */
1351 struct { /* anonymous struct used by BPF_OBJ_* commands */
1352 __aligned_u64 pathname;
1357 struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
1358 __u32 target_fd; /* container object to attach to */
1359 __u32 attach_bpf_fd; /* eBPF program to attach */
1362 __u32 replace_bpf_fd; /* previously attached eBPF
1363 * program to replace if
1364 * BPF_F_REPLACE is used
1368 struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
1371 __u32 data_size_in; /* input: len of data_in */
1372 __u32 data_size_out; /* input/output: len of data_out
1373 * returns ENOSPC if data_out
1376 __aligned_u64 data_in;
1377 __aligned_u64 data_out;
1380 __u32 ctx_size_in; /* input: len of ctx_in */
1381 __u32 ctx_size_out; /* input/output: len of ctx_out
1382 * returns ENOSPC if ctx_out
1385 __aligned_u64 ctx_in;
1386 __aligned_u64 ctx_out;
1391 struct { /* anonymous struct used by BPF_*_GET_*_ID */
1403 struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
1409 struct { /* anonymous struct used by BPF_PROG_QUERY command */
1410 __u32 target_fd; /* container object to query */
1414 __aligned_u64 prog_ids;
1418 struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
1423 struct { /* anonymous struct for BPF_BTF_LOAD */
1425 __aligned_u64 btf_log_buf;
1428 __u32 btf_log_level;
1432 __u32 pid; /* input: pid */
1433 __u32 fd; /* input: fd */
1434 __u32 flags; /* input: flags */
1435 __u32 buf_len; /* input/output: buf len */
1436 __aligned_u64 buf; /* input/output:
1437 * tp_name for tracepoint
1439 * filename for uprobe
1441 __u32 prog_id; /* output: prod_id */
1442 __u32 fd_type; /* output: BPF_FD_TYPE_* */
1443 __u64 probe_offset; /* output: probe_offset */
1444 __u64 probe_addr; /* output: probe_addr */
1447 struct { /* struct used by BPF_LINK_CREATE command */
1448 __u32 prog_fd; /* eBPF program to attach */
1450 __u32 target_fd; /* object to attach to */
1451 __u32 target_ifindex; /* target ifindex */
1453 __u32 attach_type; /* attach type */
1454 __u32 flags; /* extra flags */
1456 __u32 target_btf_id; /* btf_id of target to attach to */
1458 __aligned_u64 iter_info; /* extra bpf_iter_link_info */
1459 __u32 iter_info_len; /* iter_info length */
1462 /* black box user-provided value passed through
1463 * to BPF program at the execution time and
1464 * accessible through bpf_get_attach_cookie() BPF helper
1471 struct { /* struct used by BPF_LINK_UPDATE command */
1472 __u32 link_fd; /* link fd */
1473 /* new program fd to update link with */
1475 __u32 flags; /* extra flags */
1476 /* expected link's program fd; is specified only if
1477 * BPF_F_REPLACE flag is set in flags */
1485 struct { /* struct used by BPF_ENABLE_STATS command */
1489 struct { /* struct used by BPF_ITER_CREATE command */
1494 struct { /* struct used by BPF_PROG_BIND_MAP command */
1497 __u32 flags; /* extra flags */
1500 } __attribute__((aligned(8)));
1502 /* The description below is an attempt at providing documentation to eBPF
1503 * developers about the multiple available eBPF helper functions. It can be
1504 * parsed and used to produce a manual page. The workflow is the following,
1505 * and requires the rst2man utility:
1507 * $ ./scripts/bpf_doc.py \
1508 * --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
1509 * $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
1510 * $ man /tmp/bpf-helpers.7
1512 * Note that in order to produce this external documentation, some RST
1513 * formatting is used in the descriptions to get "bold" and "italics" in
1514 * manual pages. Also note that the few trailing white spaces are
1515 * intentional, removing them would break paragraphs for rst2man.
1517 * Start of BPF helper function descriptions:
1519 * void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
1521 * Perform a lookup in *map* for an entry associated to *key*.
1523 * Map value associated to *key*, or **NULL** if no entry was
1526 * long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
1528 * Add or update the value of the entry associated to *key* in
1529 * *map* with *value*. *flags* is one of:
1532 * The entry for *key* must not exist in the map.
1534 * The entry for *key* must already exist in the map.
1536 * No condition on the existence of the entry for *key*.
1538 * Flag value **BPF_NOEXIST** cannot be used for maps of types
1539 * **BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY** (all
1540 * elements always exist), the helper would return an error.
1542 * 0 on success, or a negative error in case of failure.
1544 * long bpf_map_delete_elem(struct bpf_map *map, const void *key)
1546 * Delete entry with *key* from *map*.
1548 * 0 on success, or a negative error in case of failure.
1550 * long bpf_probe_read(void *dst, u32 size, const void *unsafe_ptr)
1552 * For tracing programs, safely attempt to read *size* bytes from
1553 * kernel space address *unsafe_ptr* and store the data in *dst*.
1555 * Generally, use **bpf_probe_read_user**\ () or
1556 * **bpf_probe_read_kernel**\ () instead.
1558 * 0 on success, or a negative error in case of failure.
1560 * u64 bpf_ktime_get_ns(void)
1562 * Return the time elapsed since system boot, in nanoseconds.
1563 * Does not include time the system was suspended.
1564 * See: **clock_gettime**\ (**CLOCK_MONOTONIC**)
1568 * long bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
1570 * This helper is a "printk()-like" facility for debugging. It
1571 * prints a message defined by format *fmt* (of size *fmt_size*)
1572 * to file *\/sys/kernel/debug/tracing/trace* from DebugFS, if
1573 * available. It can take up to three additional **u64**
1574 * arguments (as an eBPF helpers, the total number of arguments is
1577 * Each time the helper is called, it appends a line to the trace.
1578 * Lines are discarded while *\/sys/kernel/debug/tracing/trace* is
1579 * open, use *\/sys/kernel/debug/tracing/trace_pipe* to avoid this.
1580 * The format of the trace is customizable, and the exact output
1581 * one will get depends on the options set in
1582 * *\/sys/kernel/debug/tracing/trace_options* (see also the
1583 * *README* file under the same directory). However, it usually
1584 * defaults to something like:
1588 * telnet-470 [001] .N.. 419421.045894: 0x00000001: <formatted msg>
1592 * * ``telnet`` is the name of the current task.
1593 * * ``470`` is the PID of the current task.
1594 * * ``001`` is the CPU number on which the task is
1596 * * In ``.N..``, each character refers to a set of
1597 * options (whether irqs are enabled, scheduling
1598 * options, whether hard/softirqs are running, level of
1599 * preempt_disabled respectively). **N** means that
1600 * **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
1602 * * ``419421.045894`` is a timestamp.
1603 * * ``0x00000001`` is a fake value used by BPF for the
1604 * instruction pointer register.
1605 * * ``<formatted msg>`` is the message formatted with
1608 * The conversion specifiers supported by *fmt* are similar, but
1609 * more limited than for printk(). They are **%d**, **%i**,
1610 * **%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
1611 * **%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
1612 * of field, padding with zeroes, etc.) is available, and the
1613 * helper will return **-EINVAL** (but print nothing) if it
1614 * encounters an unknown specifier.
1616 * Also, note that **bpf_trace_printk**\ () is slow, and should
1617 * only be used for debugging purposes. For this reason, a notice
1618 * block (spanning several lines) is printed to kernel logs and
1619 * states that the helper should not be used "for production use"
1620 * the first time this helper is used (or more precisely, when
1621 * **trace_printk**\ () buffers are allocated). For passing values
1622 * to user space, perf events should be preferred.
1624 * The number of bytes written to the buffer, or a negative error
1625 * in case of failure.
1627 * u32 bpf_get_prandom_u32(void)
1629 * Get a pseudo-random number.
1631 * From a security point of view, this helper uses its own
1632 * pseudo-random internal state, and cannot be used to infer the
1633 * seed of other random functions in the kernel. However, it is
1634 * essential to note that the generator used by the helper is not
1635 * cryptographically secure.
1637 * A random 32-bit unsigned value.
1639 * u32 bpf_get_smp_processor_id(void)
1641 * Get the SMP (symmetric multiprocessing) processor id. Note that
1642 * all programs run with migration disabled, which means that the
1643 * SMP processor id is stable during all the execution of the
1646 * The SMP id of the processor running the program.
1648 * long bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
1650 * Store *len* bytes from address *from* into the packet
1651 * associated to *skb*, at *offset*. *flags* are a combination of
1652 * **BPF_F_RECOMPUTE_CSUM** (automatically recompute the
1653 * checksum for the packet after storing the bytes) and
1654 * **BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
1655 * **->swhash** and *skb*\ **->l4hash** to 0).
1657 * A call to this helper is susceptible to change the underlying
1658 * packet buffer. Therefore, at load time, all checks on pointers
1659 * previously done by the verifier are invalidated and must be
1660 * performed again, if the helper is used in combination with
1661 * direct packet access.
1663 * 0 on success, or a negative error in case of failure.
1665 * long bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
1667 * Recompute the layer 3 (e.g. IP) checksum for the packet
1668 * associated to *skb*. Computation is incremental, so the helper
1669 * must know the former value of the header field that was
1670 * modified (*from*), the new value of this field (*to*), and the
1671 * number of bytes (2 or 4) for this field, stored in *size*.
1672 * Alternatively, it is possible to store the difference between
1673 * the previous and the new values of the header field in *to*, by
1674 * setting *from* and *size* to 0. For both methods, *offset*
1675 * indicates the location of the IP checksum within the packet.
1677 * This helper works in combination with **bpf_csum_diff**\ (),
1678 * which does not update the checksum in-place, but offers more
1679 * flexibility and can handle sizes larger than 2 or 4 for the
1680 * checksum to update.
1682 * A call to this helper is susceptible to change the underlying
1683 * packet buffer. Therefore, at load time, all checks on pointers
1684 * previously done by the verifier are invalidated and must be
1685 * performed again, if the helper is used in combination with
1686 * direct packet access.
1688 * 0 on success, or a negative error in case of failure.
1690 * long bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
1692 * Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
1693 * packet associated to *skb*. Computation is incremental, so the
1694 * helper must know the former value of the header field that was
1695 * modified (*from*), the new value of this field (*to*), and the
1696 * number of bytes (2 or 4) for this field, stored on the lowest
1697 * four bits of *flags*. Alternatively, it is possible to store
1698 * the difference between the previous and the new values of the
1699 * header field in *to*, by setting *from* and the four lowest
1700 * bits of *flags* to 0. For both methods, *offset* indicates the
1701 * location of the IP checksum within the packet. In addition to
1702 * the size of the field, *flags* can be added (bitwise OR) actual
1703 * flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
1704 * untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
1705 * for updates resulting in a null checksum the value is set to
1706 * **CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
1707 * the checksum is to be computed against a pseudo-header.
1709 * This helper works in combination with **bpf_csum_diff**\ (),
1710 * which does not update the checksum in-place, but offers more
1711 * flexibility and can handle sizes larger than 2 or 4 for the
1712 * checksum to update.
1714 * A call to this helper is susceptible to change the underlying
1715 * packet buffer. Therefore, at load time, all checks on pointers
1716 * previously done by the verifier are invalidated and must be
1717 * performed again, if the helper is used in combination with
1718 * direct packet access.
1720 * 0 on success, or a negative error in case of failure.
1722 * long bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
1724 * This special helper is used to trigger a "tail call", or in
1725 * other words, to jump into another eBPF program. The same stack
1726 * frame is used (but values on stack and in registers for the
1727 * caller are not accessible to the callee). This mechanism allows
1728 * for program chaining, either for raising the maximum number of
1729 * available eBPF instructions, or to execute given programs in
1730 * conditional blocks. For security reasons, there is an upper
1731 * limit to the number of successive tail calls that can be
1734 * Upon call of this helper, the program attempts to jump into a
1735 * program referenced at index *index* in *prog_array_map*, a
1736 * special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
1737 * *ctx*, a pointer to the context.
1739 * If the call succeeds, the kernel immediately runs the first
1740 * instruction of the new program. This is not a function call,
1741 * and it never returns to the previous program. If the call
1742 * fails, then the helper has no effect, and the caller continues
1743 * to run its subsequent instructions. A call can fail if the
1744 * destination program for the jump does not exist (i.e. *index*
1745 * is superior to the number of entries in *prog_array_map*), or
1746 * if the maximum number of tail calls has been reached for this
1747 * chain of programs. This limit is defined in the kernel by the
1748 * macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
1749 * which is currently set to 33.
1751 * 0 on success, or a negative error in case of failure.
1753 * long bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
1755 * Clone and redirect the packet associated to *skb* to another
1756 * net device of index *ifindex*. Both ingress and egress
1757 * interfaces can be used for redirection. The **BPF_F_INGRESS**
1758 * value in *flags* is used to make the distinction (ingress path
1759 * is selected if the flag is present, egress path otherwise).
1760 * This is the only flag supported for now.
1762 * In comparison with **bpf_redirect**\ () helper,
1763 * **bpf_clone_redirect**\ () has the associated cost of
1764 * duplicating the packet buffer, but this can be executed out of
1765 * the eBPF program. Conversely, **bpf_redirect**\ () is more
1766 * efficient, but it is handled through an action code where the
1767 * redirection happens only after the eBPF program has returned.
1769 * A call to this helper is susceptible to change the underlying
1770 * packet buffer. Therefore, at load time, all checks on pointers
1771 * previously done by the verifier are invalidated and must be
1772 * performed again, if the helper is used in combination with
1773 * direct packet access.
1775 * 0 on success, or a negative error in case of failure.
1777 * u64 bpf_get_current_pid_tgid(void)
1779 * A 64-bit integer containing the current tgid and pid, and
1781 * *current_task*\ **->tgid << 32 \|**
1782 * *current_task*\ **->pid**.
1784 * u64 bpf_get_current_uid_gid(void)
1786 * A 64-bit integer containing the current GID and UID, and
1787 * created as such: *current_gid* **<< 32 \|** *current_uid*.
1789 * long bpf_get_current_comm(void *buf, u32 size_of_buf)
1791 * Copy the **comm** attribute of the current task into *buf* of
1792 * *size_of_buf*. The **comm** attribute contains the name of
1793 * the executable (excluding the path) for the current task. The
1794 * *size_of_buf* must be strictly positive. On success, the
1795 * helper makes sure that the *buf* is NUL-terminated. On failure,
1796 * it is filled with zeroes.
1798 * 0 on success, or a negative error in case of failure.
1800 * u32 bpf_get_cgroup_classid(struct sk_buff *skb)
1802 * Retrieve the classid for the current task, i.e. for the net_cls
1803 * cgroup to which *skb* belongs.
1805 * This helper can be used on TC egress path, but not on ingress.
1807 * The net_cls cgroup provides an interface to tag network packets
1808 * based on a user-provided identifier for all traffic coming from
1809 * the tasks belonging to the related cgroup. See also the related
1810 * kernel documentation, available from the Linux sources in file
1811 * *Documentation/admin-guide/cgroup-v1/net_cls.rst*.
1813 * The Linux kernel has two versions for cgroups: there are
1814 * cgroups v1 and cgroups v2. Both are available to users, who can
1815 * use a mixture of them, but note that the net_cls cgroup is for
1816 * cgroup v1 only. This makes it incompatible with BPF programs
1817 * run on cgroups, which is a cgroup-v2-only feature (a socket can
1818 * only hold data for one version of cgroups at a time).
1820 * This helper is only available is the kernel was compiled with
1821 * the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
1822 * "**y**" or to "**m**".
1824 * The classid, or 0 for the default unconfigured classid.
1826 * long bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
1828 * Push a *vlan_tci* (VLAN tag control information) of protocol
1829 * *vlan_proto* to the packet associated to *skb*, then update
1830 * the checksum. Note that if *vlan_proto* is different from
1831 * **ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
1832 * be **ETH_P_8021Q**.
1834 * A call to this helper is susceptible to change the underlying
1835 * packet buffer. Therefore, at load time, all checks on pointers
1836 * previously done by the verifier are invalidated and must be
1837 * performed again, if the helper is used in combination with
1838 * direct packet access.
1840 * 0 on success, or a negative error in case of failure.
1842 * long bpf_skb_vlan_pop(struct sk_buff *skb)
1844 * Pop a VLAN header from the packet associated to *skb*.
1846 * A call to this helper is susceptible to change the underlying
1847 * packet buffer. Therefore, at load time, all checks on pointers
1848 * previously done by the verifier are invalidated and must be
1849 * performed again, if the helper is used in combination with
1850 * direct packet access.
1852 * 0 on success, or a negative error in case of failure.
1854 * long bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
1856 * Get tunnel metadata. This helper takes a pointer *key* to an
1857 * empty **struct bpf_tunnel_key** of **size**, that will be
1858 * filled with tunnel metadata for the packet associated to *skb*.
1859 * The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
1860 * indicates that the tunnel is based on IPv6 protocol instead of
1863 * The **struct bpf_tunnel_key** is an object that generalizes the
1864 * principal parameters used by various tunneling protocols into a
1865 * single struct. This way, it can be used to easily make a
1866 * decision based on the contents of the encapsulation header,
1867 * "summarized" in this struct. In particular, it holds the IP
1868 * address of the remote end (IPv4 or IPv6, depending on the case)
1869 * in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
1870 * this struct exposes the *key*\ **->tunnel_id**, which is
1871 * generally mapped to a VNI (Virtual Network Identifier), making
1872 * it programmable together with the **bpf_skb_set_tunnel_key**\
1875 * Let's imagine that the following code is part of a program
1876 * attached to the TC ingress interface, on one end of a GRE
1877 * tunnel, and is supposed to filter out all messages coming from
1878 * remote ends with IPv4 address other than 10.0.0.1:
1883 * struct bpf_tunnel_key key = {};
1885 * ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
1887 * return TC_ACT_SHOT; // drop packet
1889 * if (key.remote_ipv4 != 0x0a000001)
1890 * return TC_ACT_SHOT; // drop packet
1892 * return TC_ACT_OK; // accept packet
1894 * This interface can also be used with all encapsulation devices
1895 * that can operate in "collect metadata" mode: instead of having
1896 * one network device per specific configuration, the "collect
1897 * metadata" mode only requires a single device where the
1898 * configuration can be extracted from this helper.
1900 * This can be used together with various tunnels such as VXLan,
1901 * Geneve, GRE or IP in IP (IPIP).
1903 * 0 on success, or a negative error in case of failure.
1905 * long bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
1907 * Populate tunnel metadata for packet associated to *skb.* The
1908 * tunnel metadata is set to the contents of *key*, of *size*. The
1909 * *flags* can be set to a combination of the following values:
1911 * **BPF_F_TUNINFO_IPV6**
1912 * Indicate that the tunnel is based on IPv6 protocol
1914 * **BPF_F_ZERO_CSUM_TX**
1915 * For IPv4 packets, add a flag to tunnel metadata
1916 * indicating that checksum computation should be skipped
1917 * and checksum set to zeroes.
1918 * **BPF_F_DONT_FRAGMENT**
1919 * Add a flag to tunnel metadata indicating that the
1920 * packet should not be fragmented.
1921 * **BPF_F_SEQ_NUMBER**
1922 * Add a flag to tunnel metadata indicating that a
1923 * sequence number should be added to tunnel header before
1924 * sending the packet. This flag was added for GRE
1925 * encapsulation, but might be used with other protocols
1926 * as well in the future.
1928 * Here is a typical usage on the transmit path:
1932 * struct bpf_tunnel_key key;
1934 * bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
1935 * bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
1937 * See also the description of the **bpf_skb_get_tunnel_key**\ ()
1938 * helper for additional information.
1940 * 0 on success, or a negative error in case of failure.
1942 * u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
1944 * Read the value of a perf event counter. This helper relies on a
1945 * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
1946 * the perf event counter is selected when *map* is updated with
1947 * perf event file descriptors. The *map* is an array whose size
1948 * is the number of available CPUs, and each cell contains a value
1949 * relative to one CPU. The value to retrieve is indicated by
1950 * *flags*, that contains the index of the CPU to look up, masked
1951 * with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
1952 * **BPF_F_CURRENT_CPU** to indicate that the value for the
1953 * current CPU should be retrieved.
1955 * Note that before Linux 4.13, only hardware perf event can be
1958 * Also, be aware that the newer helper
1959 * **bpf_perf_event_read_value**\ () is recommended over
1960 * **bpf_perf_event_read**\ () in general. The latter has some ABI
1961 * quirks where error and counter value are used as a return code
1962 * (which is wrong to do since ranges may overlap). This issue is
1963 * fixed with **bpf_perf_event_read_value**\ (), which at the same
1964 * time provides more features over the **bpf_perf_event_read**\
1965 * () interface. Please refer to the description of
1966 * **bpf_perf_event_read_value**\ () for details.
1968 * The value of the perf event counter read from the map, or a
1969 * negative error code in case of failure.
1971 * long bpf_redirect(u32 ifindex, u64 flags)
1973 * Redirect the packet to another net device of index *ifindex*.
1974 * This helper is somewhat similar to **bpf_clone_redirect**\
1975 * (), except that the packet is not cloned, which provides
1976 * increased performance.
1978 * Except for XDP, both ingress and egress interfaces can be used
1979 * for redirection. The **BPF_F_INGRESS** value in *flags* is used
1980 * to make the distinction (ingress path is selected if the flag
1981 * is present, egress path otherwise). Currently, XDP only
1982 * supports redirection to the egress interface, and accepts no
1985 * The same effect can also be attained with the more generic
1986 * **bpf_redirect_map**\ (), which uses a BPF map to store the
1987 * redirect target instead of providing it directly to the helper.
1989 * For XDP, the helper returns **XDP_REDIRECT** on success or
1990 * **XDP_ABORTED** on error. For other program types, the values
1991 * are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
1994 * u32 bpf_get_route_realm(struct sk_buff *skb)
1996 * Retrieve the realm or the route, that is to say the
1997 * **tclassid** field of the destination for the *skb*. The
1998 * identifier retrieved is a user-provided tag, similar to the
1999 * one used with the net_cls cgroup (see description for
2000 * **bpf_get_cgroup_classid**\ () helper), but here this tag is
2001 * held by a route (a destination entry), not by a task.
2003 * Retrieving this identifier works with the clsact TC egress hook
2004 * (see also **tc-bpf(8)**), or alternatively on conventional
2005 * classful egress qdiscs, but not on TC ingress path. In case of
2006 * clsact TC egress hook, this has the advantage that, internally,
2007 * the destination entry has not been dropped yet in the transmit
2008 * path. Therefore, the destination entry does not need to be
2009 * artificially held via **netif_keep_dst**\ () for a classful
2010 * qdisc until the *skb* is freed.
2012 * This helper is available only if the kernel was compiled with
2013 * **CONFIG_IP_ROUTE_CLASSID** configuration option.
2015 * The realm of the route for the packet associated to *skb*, or 0
2016 * if none was found.
2018 * long bpf_perf_event_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
2020 * Write raw *data* blob into a special BPF perf event held by
2021 * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
2022 * event must have the following attributes: **PERF_SAMPLE_RAW**
2023 * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
2024 * **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
2026 * The *flags* are used to indicate the index in *map* for which
2027 * the value must be put, masked with **BPF_F_INDEX_MASK**.
2028 * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
2029 * to indicate that the index of the current CPU core should be
2032 * The value to write, of *size*, is passed through eBPF stack and
2033 * pointed by *data*.
2035 * The context of the program *ctx* needs also be passed to the
2038 * On user space, a program willing to read the values needs to
2039 * call **perf_event_open**\ () on the perf event (either for
2040 * one or for all CPUs) and to store the file descriptor into the
2041 * *map*. This must be done before the eBPF program can send data
2042 * into it. An example is available in file
2043 * *samples/bpf/trace_output_user.c* in the Linux kernel source
2044 * tree (the eBPF program counterpart is in
2045 * *samples/bpf/trace_output_kern.c*).
2047 * **bpf_perf_event_output**\ () achieves better performance
2048 * than **bpf_trace_printk**\ () for sharing data with user
2049 * space, and is much better suitable for streaming data from eBPF
2052 * Note that this helper is not restricted to tracing use cases
2053 * and can be used with programs attached to TC or XDP as well,
2054 * where it allows for passing data to user space listeners. Data
2057 * * Only custom structs,
2058 * * Only the packet payload, or
2059 * * A combination of both.
2061 * 0 on success, or a negative error in case of failure.
2063 * long bpf_skb_load_bytes(const void *skb, u32 offset, void *to, u32 len)
2065 * This helper was provided as an easy way to load data from a
2066 * packet. It can be used to load *len* bytes from *offset* from
2067 * the packet associated to *skb*, into the buffer pointed by
2070 * Since Linux 4.7, usage of this helper has mostly been replaced
2071 * by "direct packet access", enabling packet data to be
2072 * manipulated with *skb*\ **->data** and *skb*\ **->data_end**
2073 * pointing respectively to the first byte of packet data and to
2074 * the byte after the last byte of packet data. However, it
2075 * remains useful if one wishes to read large quantities of data
2076 * at once from a packet into the eBPF stack.
2078 * 0 on success, or a negative error in case of failure.
2080 * long bpf_get_stackid(void *ctx, struct bpf_map *map, u64 flags)
2082 * Walk a user or a kernel stack and return its id. To achieve
2083 * this, the helper needs *ctx*, which is a pointer to the context
2084 * on which the tracing program is executed, and a pointer to a
2085 * *map* of type **BPF_MAP_TYPE_STACK_TRACE**.
2087 * The last argument, *flags*, holds the number of stack frames to
2088 * skip (from 0 to 255), masked with
2089 * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
2090 * a combination of the following flags:
2092 * **BPF_F_USER_STACK**
2093 * Collect a user space stack instead of a kernel stack.
2094 * **BPF_F_FAST_STACK_CMP**
2095 * Compare stacks by hash only.
2096 * **BPF_F_REUSE_STACKID**
2097 * If two different stacks hash into the same *stackid*,
2098 * discard the old one.
2100 * The stack id retrieved is a 32 bit long integer handle which
2101 * can be further combined with other data (including other stack
2102 * ids) and used as a key into maps. This can be useful for
2103 * generating a variety of graphs (such as flame graphs or off-cpu
2106 * For walking a stack, this helper is an improvement over
2107 * **bpf_probe_read**\ (), which can be used with unrolled loops
2108 * but is not efficient and consumes a lot of eBPF instructions.
2109 * Instead, **bpf_get_stackid**\ () can collect up to
2110 * **PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
2111 * this limit can be controlled with the **sysctl** program, and
2112 * that it should be manually increased in order to profile long
2113 * user stacks (such as stacks for Java programs). To do so, use:
2117 * # sysctl kernel.perf_event_max_stack=<new value>
2119 * The positive or null stack id on success, or a negative error
2120 * in case of failure.
2122 * s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
2124 * Compute a checksum difference, from the raw buffer pointed by
2125 * *from*, of length *from_size* (that must be a multiple of 4),
2126 * towards the raw buffer pointed by *to*, of size *to_size*
2127 * (same remark). An optional *seed* can be added to the value
2128 * (this can be cascaded, the seed may come from a previous call
2131 * This is flexible enough to be used in several ways:
2133 * * With *from_size* == 0, *to_size* > 0 and *seed* set to
2134 * checksum, it can be used when pushing new data.
2135 * * With *from_size* > 0, *to_size* == 0 and *seed* set to
2136 * checksum, it can be used when removing data from a packet.
2137 * * With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
2138 * can be used to compute a diff. Note that *from_size* and
2139 * *to_size* do not need to be equal.
2141 * This helper can be used in combination with
2142 * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
2143 * which one can feed in the difference computed with
2144 * **bpf_csum_diff**\ ().
2146 * The checksum result, or a negative error code in case of
2149 * long bpf_skb_get_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
2151 * Retrieve tunnel options metadata for the packet associated to
2152 * *skb*, and store the raw tunnel option data to the buffer *opt*
2155 * This helper can be used with encapsulation devices that can
2156 * operate in "collect metadata" mode (please refer to the related
2157 * note in the description of **bpf_skb_get_tunnel_key**\ () for
2158 * more details). A particular example where this can be used is
2159 * in combination with the Geneve encapsulation protocol, where it
2160 * allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
2161 * and retrieving arbitrary TLVs (Type-Length-Value headers) from
2162 * the eBPF program. This allows for full customization of these
2165 * The size of the option data retrieved.
2167 * long bpf_skb_set_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
2169 * Set tunnel options metadata for the packet associated to *skb*
2170 * to the option data contained in the raw buffer *opt* of *size*.
2172 * See also the description of the **bpf_skb_get_tunnel_opt**\ ()
2173 * helper for additional information.
2175 * 0 on success, or a negative error in case of failure.
2177 * long bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
2179 * Change the protocol of the *skb* to *proto*. Currently
2180 * supported are transition from IPv4 to IPv6, and from IPv6 to
2181 * IPv4. The helper takes care of the groundwork for the
2182 * transition, including resizing the socket buffer. The eBPF
2183 * program is expected to fill the new headers, if any, via
2184 * **skb_store_bytes**\ () and to recompute the checksums with
2185 * **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
2186 * (). The main case for this helper is to perform NAT64
2187 * operations out of an eBPF program.
2189 * Internally, the GSO type is marked as dodgy so that headers are
2190 * checked and segments are recalculated by the GSO/GRO engine.
2191 * The size for GSO target is adapted as well.
2193 * All values for *flags* are reserved for future usage, and must
2196 * A call to this helper is susceptible to change the underlying
2197 * packet buffer. Therefore, at load time, all checks on pointers
2198 * previously done by the verifier are invalidated and must be
2199 * performed again, if the helper is used in combination with
2200 * direct packet access.
2202 * 0 on success, or a negative error in case of failure.
2204 * long bpf_skb_change_type(struct sk_buff *skb, u32 type)
2206 * Change the packet type for the packet associated to *skb*. This
2207 * comes down to setting *skb*\ **->pkt_type** to *type*, except
2208 * the eBPF program does not have a write access to *skb*\
2209 * **->pkt_type** beside this helper. Using a helper here allows
2210 * for graceful handling of errors.
2212 * The major use case is to change incoming *skb*s to
2213 * **PACKET_HOST** in a programmatic way instead of having to
2214 * recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
2217 * Note that *type* only allows certain values. At this time, they
2222 * **PACKET_BROADCAST**
2223 * Send packet to all.
2224 * **PACKET_MULTICAST**
2225 * Send packet to group.
2226 * **PACKET_OTHERHOST**
2227 * Send packet to someone else.
2229 * 0 on success, or a negative error in case of failure.
2231 * long bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
2233 * Check whether *skb* is a descendant of the cgroup2 held by
2234 * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
2236 * The return value depends on the result of the test, and can be:
2238 * * 0, if the *skb* failed the cgroup2 descendant test.
2239 * * 1, if the *skb* succeeded the cgroup2 descendant test.
2240 * * A negative error code, if an error occurred.
2242 * u32 bpf_get_hash_recalc(struct sk_buff *skb)
2244 * Retrieve the hash of the packet, *skb*\ **->hash**. If it is
2245 * not set, in particular if the hash was cleared due to mangling,
2246 * recompute this hash. Later accesses to the hash can be done
2247 * directly with *skb*\ **->hash**.
2249 * Calling **bpf_set_hash_invalid**\ (), changing a packet
2250 * prototype with **bpf_skb_change_proto**\ (), or calling
2251 * **bpf_skb_store_bytes**\ () with the
2252 * **BPF_F_INVALIDATE_HASH** are actions susceptible to clear
2253 * the hash and to trigger a new computation for the next call to
2254 * **bpf_get_hash_recalc**\ ().
2258 * u64 bpf_get_current_task(void)
2260 * A pointer to the current task struct.
2262 * long bpf_probe_write_user(void *dst, const void *src, u32 len)
2264 * Attempt in a safe way to write *len* bytes from the buffer
2265 * *src* to *dst* in memory. It only works for threads that are in
2266 * user context, and *dst* must be a valid user space address.
2268 * This helper should not be used to implement any kind of
2269 * security mechanism because of TOC-TOU attacks, but rather to
2270 * debug, divert, and manipulate execution of semi-cooperative
2273 * Keep in mind that this feature is meant for experiments, and it
2274 * has a risk of crashing the system and running programs.
2275 * Therefore, when an eBPF program using this helper is attached,
2276 * a warning including PID and process name is printed to kernel
2279 * 0 on success, or a negative error in case of failure.
2281 * long bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
2283 * Check whether the probe is being run is the context of a given
2284 * subset of the cgroup2 hierarchy. The cgroup2 to test is held by
2285 * *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
2287 * The return value depends on the result of the test, and can be:
2289 * * 0, if current task belongs to the cgroup2.
2290 * * 1, if current task does not belong to the cgroup2.
2291 * * A negative error code, if an error occurred.
2293 * long bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
2295 * Resize (trim or grow) the packet associated to *skb* to the
2296 * new *len*. The *flags* are reserved for future usage, and must
2299 * The basic idea is that the helper performs the needed work to
2300 * change the size of the packet, then the eBPF program rewrites
2301 * the rest via helpers like **bpf_skb_store_bytes**\ (),
2302 * **bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
2303 * and others. This helper is a slow path utility intended for
2304 * replies with control messages. And because it is targeted for
2305 * slow path, the helper itself can afford to be slow: it
2306 * implicitly linearizes, unclones and drops offloads from the
2309 * A call to this helper is susceptible to change the underlying
2310 * packet buffer. Therefore, at load time, all checks on pointers
2311 * previously done by the verifier are invalidated and must be
2312 * performed again, if the helper is used in combination with
2313 * direct packet access.
2315 * 0 on success, or a negative error in case of failure.
2317 * long bpf_skb_pull_data(struct sk_buff *skb, u32 len)
2319 * Pull in non-linear data in case the *skb* is non-linear and not
2320 * all of *len* are part of the linear section. Make *len* bytes
2321 * from *skb* readable and writable. If a zero value is passed for
2322 * *len*, then the whole length of the *skb* is pulled.
2324 * This helper is only needed for reading and writing with direct
2327 * For direct packet access, testing that offsets to access
2328 * are within packet boundaries (test on *skb*\ **->data_end**) is
2329 * susceptible to fail if offsets are invalid, or if the requested
2330 * data is in non-linear parts of the *skb*. On failure the
2331 * program can just bail out, or in the case of a non-linear
2332 * buffer, use a helper to make the data available. The
2333 * **bpf_skb_load_bytes**\ () helper is a first solution to access
2334 * the data. Another one consists in using **bpf_skb_pull_data**
2335 * to pull in once the non-linear parts, then retesting and
2336 * eventually access the data.
2338 * At the same time, this also makes sure the *skb* is uncloned,
2339 * which is a necessary condition for direct write. As this needs
2340 * to be an invariant for the write part only, the verifier
2341 * detects writes and adds a prologue that is calling
2342 * **bpf_skb_pull_data()** to effectively unclone the *skb* from
2343 * the very beginning in case it is indeed cloned.
2345 * A call to this helper is susceptible to change the underlying
2346 * packet buffer. Therefore, at load time, all checks on pointers
2347 * previously done by the verifier are invalidated and must be
2348 * performed again, if the helper is used in combination with
2349 * direct packet access.
2351 * 0 on success, or a negative error in case of failure.
2353 * s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
2355 * Add the checksum *csum* into *skb*\ **->csum** in case the
2356 * driver has supplied a checksum for the entire packet into that
2357 * field. Return an error otherwise. This helper is intended to be
2358 * used in combination with **bpf_csum_diff**\ (), in particular
2359 * when the checksum needs to be updated after data has been
2360 * written into the packet through direct packet access.
2362 * The checksum on success, or a negative error code in case of
2365 * void bpf_set_hash_invalid(struct sk_buff *skb)
2367 * Invalidate the current *skb*\ **->hash**. It can be used after
2368 * mangling on headers through direct packet access, in order to
2369 * indicate that the hash is outdated and to trigger a
2370 * recalculation the next time the kernel tries to access this
2371 * hash or when the **bpf_get_hash_recalc**\ () helper is called.
2373 * long bpf_get_numa_node_id(void)
2375 * Return the id of the current NUMA node. The primary use case
2376 * for this helper is the selection of sockets for the local NUMA
2377 * node, when the program is attached to sockets using the
2378 * **SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
2379 * but the helper is also available to other eBPF program types,
2380 * similarly to **bpf_get_smp_processor_id**\ ().
2382 * The id of current NUMA node.
2384 * long bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
2386 * Grows headroom of packet associated to *skb* and adjusts the
2387 * offset of the MAC header accordingly, adding *len* bytes of
2388 * space. It automatically extends and reallocates memory as
2391 * This helper can be used on a layer 3 *skb* to push a MAC header
2392 * for redirection into a layer 2 device.
2394 * All values for *flags* are reserved for future usage, and must
2397 * A call to this helper is susceptible to change the underlying
2398 * packet buffer. Therefore, at load time, all checks on pointers
2399 * previously done by the verifier are invalidated and must be
2400 * performed again, if the helper is used in combination with
2401 * direct packet access.
2403 * 0 on success, or a negative error in case of failure.
2405 * long bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
2407 * Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
2408 * it is possible to use a negative value for *delta*. This helper
2409 * can be used to prepare the packet for pushing or popping
2412 * A call to this helper is susceptible to change the underlying
2413 * packet buffer. Therefore, at load time, all checks on pointers
2414 * previously done by the verifier are invalidated and must be
2415 * performed again, if the helper is used in combination with
2416 * direct packet access.
2418 * 0 on success, or a negative error in case of failure.
2420 * long bpf_probe_read_str(void *dst, u32 size, const void *unsafe_ptr)
2422 * Copy a NUL terminated string from an unsafe kernel address
2423 * *unsafe_ptr* to *dst*. See **bpf_probe_read_kernel_str**\ () for
2426 * Generally, use **bpf_probe_read_user_str**\ () or
2427 * **bpf_probe_read_kernel_str**\ () instead.
2429 * On success, the strictly positive length of the string,
2430 * including the trailing NUL character. On error, a negative
2433 * u64 bpf_get_socket_cookie(struct sk_buff *skb)
2435 * If the **struct sk_buff** pointed by *skb* has a known socket,
2436 * retrieve the cookie (generated by the kernel) of this socket.
2437 * If no cookie has been set yet, generate a new cookie. Once
2438 * generated, the socket cookie remains stable for the life of the
2439 * socket. This helper can be useful for monitoring per socket
2440 * networking traffic statistics as it provides a global socket
2441 * identifier that can be assumed unique.
2443 * A 8-byte long unique number on success, or 0 if the socket
2444 * field is missing inside *skb*.
2446 * u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
2448 * Equivalent to bpf_get_socket_cookie() helper that accepts
2449 * *skb*, but gets socket from **struct bpf_sock_addr** context.
2451 * A 8-byte long unique number.
2453 * u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
2455 * Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
2456 * *skb*, but gets socket from **struct bpf_sock_ops** context.
2458 * A 8-byte long unique number.
2460 * u64 bpf_get_socket_cookie(struct sock *sk)
2462 * Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
2463 * *sk*, but gets socket from a BTF **struct sock**. This helper
2464 * also works for sleepable programs.
2466 * A 8-byte long unique number or 0 if *sk* is NULL.
2468 * u32 bpf_get_socket_uid(struct sk_buff *skb)
2470 * The owner UID of the socket associated to *skb*. If the socket
2471 * is **NULL**, or if it is not a full socket (i.e. if it is a
2472 * time-wait or a request socket instead), **overflowuid** value
2473 * is returned (note that **overflowuid** might also be the actual
2474 * UID value for the socket).
2476 * long bpf_set_hash(struct sk_buff *skb, u32 hash)
2478 * Set the full hash for *skb* (set the field *skb*\ **->hash**)
2483 * long bpf_setsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
2485 * Emulate a call to **setsockopt()** on the socket associated to
2486 * *bpf_socket*, which must be a full socket. The *level* at
2487 * which the option resides and the name *optname* of the option
2488 * must be specified, see **setsockopt(2)** for more information.
2489 * The option value of length *optlen* is pointed by *optval*.
2491 * *bpf_socket* should be one of the following:
2493 * * **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
2494 * * **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
2495 * and **BPF_CGROUP_INET6_CONNECT**.
2497 * This helper actually implements a subset of **setsockopt()**.
2498 * It supports the following *level*\ s:
2500 * * **SOL_SOCKET**, which supports the following *optname*\ s:
2501 * **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
2502 * **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
2503 * **SO_BINDTODEVICE**, **SO_KEEPALIVE**.
2504 * * **IPPROTO_TCP**, which supports the following *optname*\ s:
2505 * **TCP_CONGESTION**, **TCP_BPF_IW**,
2506 * **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
2507 * **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**,
2508 * **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**.
2509 * * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
2510 * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
2512 * 0 on success, or a negative error in case of failure.
2514 * long bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
2516 * Grow or shrink the room for data in the packet associated to
2517 * *skb* by *len_diff*, and according to the selected *mode*.
2519 * By default, the helper will reset any offloaded checksum
2520 * indicator of the skb to CHECKSUM_NONE. This can be avoided
2521 * by the following flag:
2523 * * **BPF_F_ADJ_ROOM_NO_CSUM_RESET**: Do not reset offloaded
2524 * checksum data of the skb to CHECKSUM_NONE.
2526 * There are two supported modes at this time:
2528 * * **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
2529 * (room space is added or removed below the layer 2 header).
2531 * * **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
2532 * (room space is added or removed below the layer 3 header).
2534 * The following flags are supported at this time:
2536 * * **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
2537 * Adjusting mss in this way is not allowed for datagrams.
2539 * * **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**,
2540 * **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**:
2541 * Any new space is reserved to hold a tunnel header.
2542 * Configure skb offsets and other fields accordingly.
2544 * * **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**,
2545 * **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**:
2546 * Use with ENCAP_L3 flags to further specify the tunnel type.
2548 * * **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*):
2549 * Use with ENCAP_L3/L4 flags to further specify the tunnel
2550 * type; *len* is the length of the inner MAC header.
2552 * * **BPF_F_ADJ_ROOM_ENCAP_L2_ETH**:
2553 * Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the
2554 * L2 type as Ethernet.
2556 * A call to this helper is susceptible to change the underlying
2557 * packet buffer. Therefore, at load time, all checks on pointers
2558 * previously done by the verifier are invalidated and must be
2559 * performed again, if the helper is used in combination with
2560 * direct packet access.
2562 * 0 on success, or a negative error in case of failure.
2564 * long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags)
2566 * Redirect the packet to the endpoint referenced by *map* at
2567 * index *key*. Depending on its type, this *map* can contain
2568 * references to net devices (for forwarding packets through other
2569 * ports), or to CPUs (for redirecting XDP frames to another CPU;
2570 * but this is only implemented for native XDP (with driver
2571 * support) as of this writing).
2573 * The lower two bits of *flags* are used as the return code if
2574 * the map lookup fails. This is so that the return value can be
2575 * one of the XDP program return codes up to **XDP_TX**, as chosen
2576 * by the caller. The higher bits of *flags* can be set to
2577 * BPF_F_BROADCAST or BPF_F_EXCLUDE_INGRESS as defined below.
2579 * With BPF_F_BROADCAST the packet will be broadcasted to all the
2580 * interfaces in the map, with BPF_F_EXCLUDE_INGRESS the ingress
2581 * interface will be excluded when do broadcasting.
2583 * See also **bpf_redirect**\ (), which only supports redirecting
2584 * to an ifindex, but doesn't require a map to do so.
2586 * **XDP_REDIRECT** on success, or the value of the two lower bits
2587 * of the *flags* argument on error.
2589 * long bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
2591 * Redirect the packet to the socket referenced by *map* (of type
2592 * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
2593 * egress interfaces can be used for redirection. The
2594 * **BPF_F_INGRESS** value in *flags* is used to make the
2595 * distinction (ingress path is selected if the flag is present,
2596 * egress path otherwise). This is the only flag supported for now.
2598 * **SK_PASS** on success, or **SK_DROP** on error.
2600 * long bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
2602 * Add an entry to, or update a *map* referencing sockets. The
2603 * *skops* is used as a new value for the entry associated to
2604 * *key*. *flags* is one of:
2607 * The entry for *key* must not exist in the map.
2609 * The entry for *key* must already exist in the map.
2611 * No condition on the existence of the entry for *key*.
2613 * If the *map* has eBPF programs (parser and verdict), those will
2614 * be inherited by the socket being added. If the socket is
2615 * already attached to eBPF programs, this results in an error.
2617 * 0 on success, or a negative error in case of failure.
2619 * long bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
2621 * Adjust the address pointed by *xdp_md*\ **->data_meta** by
2622 * *delta* (which can be positive or negative). Note that this
2623 * operation modifies the address stored in *xdp_md*\ **->data**,
2624 * so the latter must be loaded only after the helper has been
2627 * The use of *xdp_md*\ **->data_meta** is optional and programs
2628 * are not required to use it. The rationale is that when the
2629 * packet is processed with XDP (e.g. as DoS filter), it is
2630 * possible to push further meta data along with it before passing
2631 * to the stack, and to give the guarantee that an ingress eBPF
2632 * program attached as a TC classifier on the same device can pick
2633 * this up for further post-processing. Since TC works with socket
2634 * buffers, it remains possible to set from XDP the **mark** or
2635 * **priority** pointers, or other pointers for the socket buffer.
2636 * Having this scratch space generic and programmable allows for
2637 * more flexibility as the user is free to store whatever meta
2640 * A call to this helper is susceptible to change the underlying
2641 * packet buffer. Therefore, at load time, all checks on pointers
2642 * previously done by the verifier are invalidated and must be
2643 * performed again, if the helper is used in combination with
2644 * direct packet access.
2646 * 0 on success, or a negative error in case of failure.
2648 * long bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
2650 * Read the value of a perf event counter, and store it into *buf*
2651 * of size *buf_size*. This helper relies on a *map* of type
2652 * **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
2653 * counter is selected when *map* is updated with perf event file
2654 * descriptors. The *map* is an array whose size is the number of
2655 * available CPUs, and each cell contains a value relative to one
2656 * CPU. The value to retrieve is indicated by *flags*, that
2657 * contains the index of the CPU to look up, masked with
2658 * **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
2659 * **BPF_F_CURRENT_CPU** to indicate that the value for the
2660 * current CPU should be retrieved.
2662 * This helper behaves in a way close to
2663 * **bpf_perf_event_read**\ () helper, save that instead of
2664 * just returning the value observed, it fills the *buf*
2665 * structure. This allows for additional data to be retrieved: in
2666 * particular, the enabled and running times (in *buf*\
2667 * **->enabled** and *buf*\ **->running**, respectively) are
2668 * copied. In general, **bpf_perf_event_read_value**\ () is
2669 * recommended over **bpf_perf_event_read**\ (), which has some
2670 * ABI issues and provides fewer functionalities.
2672 * These values are interesting, because hardware PMU (Performance
2673 * Monitoring Unit) counters are limited resources. When there are
2674 * more PMU based perf events opened than available counters,
2675 * kernel will multiplex these events so each event gets certain
2676 * percentage (but not all) of the PMU time. In case that
2677 * multiplexing happens, the number of samples or counter value
2678 * will not reflect the case compared to when no multiplexing
2679 * occurs. This makes comparison between different runs difficult.
2680 * Typically, the counter value should be normalized before
2681 * comparing to other experiments. The usual normalization is done
2686 * normalized_counter = counter * t_enabled / t_running
2688 * Where t_enabled is the time enabled for event and t_running is
2689 * the time running for event since last normalization. The
2690 * enabled and running times are accumulated since the perf event
2691 * open. To achieve scaling factor between two invocations of an
2692 * eBPF program, users can use CPU id as the key (which is
2693 * typical for perf array usage model) to remember the previous
2694 * value and do the calculation inside the eBPF program.
2696 * 0 on success, or a negative error in case of failure.
2698 * long bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
2700 * For en eBPF program attached to a perf event, retrieve the
2701 * value of the event counter associated to *ctx* and store it in
2702 * the structure pointed by *buf* and of size *buf_size*. Enabled
2703 * and running times are also stored in the structure (see
2704 * description of helper **bpf_perf_event_read_value**\ () for
2707 * 0 on success, or a negative error in case of failure.
2709 * long bpf_getsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
2711 * Emulate a call to **getsockopt()** on the socket associated to
2712 * *bpf_socket*, which must be a full socket. The *level* at
2713 * which the option resides and the name *optname* of the option
2714 * must be specified, see **getsockopt(2)** for more information.
2715 * The retrieved value is stored in the structure pointed by
2716 * *opval* and of length *optlen*.
2718 * *bpf_socket* should be one of the following:
2720 * * **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
2721 * * **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**
2722 * and **BPF_CGROUP_INET6_CONNECT**.
2724 * This helper actually implements a subset of **getsockopt()**.
2725 * It supports the following *level*\ s:
2727 * * **IPPROTO_TCP**, which supports *optname*
2728 * **TCP_CONGESTION**.
2729 * * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
2730 * * **IPPROTO_IPV6**, which supports *optname* **IPV6_TCLASS**.
2732 * 0 on success, or a negative error in case of failure.
2734 * long bpf_override_return(struct pt_regs *regs, u64 rc)
2736 * Used for error injection, this helper uses kprobes to override
2737 * the return value of the probed function, and to set it to *rc*.
2738 * The first argument is the context *regs* on which the kprobe
2741 * This helper works by setting the PC (program counter)
2742 * to an override function which is run in place of the original
2743 * probed function. This means the probed function is not run at
2744 * all. The replacement function just returns with the required
2747 * This helper has security implications, and thus is subject to
2748 * restrictions. It is only available if the kernel was compiled
2749 * with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
2750 * option, and in this case it only works on functions tagged with
2751 * **ALLOW_ERROR_INJECTION** in the kernel code.
2753 * Also, the helper is only available for the architectures having
2754 * the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
2755 * x86 architecture is the only one to support this feature.
2759 * long bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
2761 * Attempt to set the value of the **bpf_sock_ops_cb_flags** field
2762 * for the full TCP socket associated to *bpf_sock_ops* to
2765 * The primary use of this field is to determine if there should
2766 * be calls to eBPF programs of type
2767 * **BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
2768 * code. A program of the same type can change its value, per
2769 * connection and as necessary, when the connection is
2770 * established. This field is directly accessible for reading, but
2771 * this helper must be used for updates in order to return an
2772 * error if an eBPF program tries to set a callback that is not
2773 * supported in the current kernel.
2775 * *argval* is a flag array which can combine these flags:
2777 * * **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
2778 * * **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
2779 * * **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
2780 * * **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT)
2782 * Therefore, this function can be used to clear a callback flag by
2783 * setting the appropriate bit to zero. e.g. to disable the RTO
2786 * **bpf_sock_ops_cb_flags_set(bpf_sock,**
2787 * **bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)**
2789 * Here are some examples of where one could call such eBPF
2793 * * When a packet is retransmitted.
2794 * * When the connection terminates.
2795 * * When a packet is sent.
2796 * * When a packet is received.
2798 * Code **-EINVAL** if the socket is not a full TCP socket;
2799 * otherwise, a positive number containing the bits that could not
2800 * be set is returned (which comes down to 0 if all bits were set
2803 * long bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
2805 * This helper is used in programs implementing policies at the
2806 * socket level. If the message *msg* is allowed to pass (i.e. if
2807 * the verdict eBPF program returns **SK_PASS**), redirect it to
2808 * the socket referenced by *map* (of type
2809 * **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
2810 * egress interfaces can be used for redirection. The
2811 * **BPF_F_INGRESS** value in *flags* is used to make the
2812 * distinction (ingress path is selected if the flag is present,
2813 * egress path otherwise). This is the only flag supported for now.
2815 * **SK_PASS** on success, or **SK_DROP** on error.
2817 * long bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
2819 * For socket policies, apply the verdict of the eBPF program to
2820 * the next *bytes* (number of bytes) of message *msg*.
2822 * For example, this helper can be used in the following cases:
2824 * * A single **sendmsg**\ () or **sendfile**\ () system call
2825 * contains multiple logical messages that the eBPF program is
2826 * supposed to read and for which it should apply a verdict.
2827 * * An eBPF program only cares to read the first *bytes* of a
2828 * *msg*. If the message has a large payload, then setting up
2829 * and calling the eBPF program repeatedly for all bytes, even
2830 * though the verdict is already known, would create unnecessary
2833 * When called from within an eBPF program, the helper sets a
2834 * counter internal to the BPF infrastructure, that is used to
2835 * apply the last verdict to the next *bytes*. If *bytes* is
2836 * smaller than the current data being processed from a
2837 * **sendmsg**\ () or **sendfile**\ () system call, the first
2838 * *bytes* will be sent and the eBPF program will be re-run with
2839 * the pointer for start of data pointing to byte number *bytes*
2840 * **+ 1**. If *bytes* is larger than the current data being
2841 * processed, then the eBPF verdict will be applied to multiple
2842 * **sendmsg**\ () or **sendfile**\ () calls until *bytes* are
2845 * Note that if a socket closes with the internal counter holding
2846 * a non-zero value, this is not a problem because data is not
2847 * being buffered for *bytes* and is sent as it is received.
2851 * long bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
2853 * For socket policies, prevent the execution of the verdict eBPF
2854 * program for message *msg* until *bytes* (byte number) have been
2857 * This can be used when one needs a specific number of bytes
2858 * before a verdict can be assigned, even if the data spans
2859 * multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
2860 * case would be a user calling **sendmsg**\ () repeatedly with
2861 * 1-byte long message segments. Obviously, this is bad for
2862 * performance, but it is still valid. If the eBPF program needs
2863 * *bytes* bytes to validate a header, this helper can be used to
2864 * prevent the eBPF program to be called again until *bytes* have
2869 * long bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
2871 * For socket policies, pull in non-linear data from user space
2872 * for *msg* and set pointers *msg*\ **->data** and *msg*\
2873 * **->data_end** to *start* and *end* bytes offsets into *msg*,
2876 * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
2877 * *msg* it can only parse data that the (**data**, **data_end**)
2878 * pointers have already consumed. For **sendmsg**\ () hooks this
2879 * is likely the first scatterlist element. But for calls relying
2880 * on the **sendpage** handler (e.g. **sendfile**\ ()) this will
2881 * be the range (**0**, **0**) because the data is shared with
2882 * user space and by default the objective is to avoid allowing
2883 * user space to modify data while (or after) eBPF verdict is
2884 * being decided. This helper can be used to pull in data and to
2885 * set the start and end pointer to given values. Data will be
2886 * copied if necessary (i.e. if data was not linear and if start
2887 * and end pointers do not point to the same chunk).
2889 * A call to this helper is susceptible to change the underlying
2890 * packet buffer. Therefore, at load time, all checks on pointers
2891 * previously done by the verifier are invalidated and must be
2892 * performed again, if the helper is used in combination with
2893 * direct packet access.
2895 * All values for *flags* are reserved for future usage, and must
2898 * 0 on success, or a negative error in case of failure.
2900 * long bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
2902 * Bind the socket associated to *ctx* to the address pointed by
2903 * *addr*, of length *addr_len*. This allows for making outgoing
2904 * connection from the desired IP address, which can be useful for
2905 * example when all processes inside a cgroup should use one
2906 * single IP address on a host that has multiple IP configured.
2908 * This helper works for IPv4 and IPv6, TCP and UDP sockets. The
2909 * domain (*addr*\ **->sa_family**) must be **AF_INET** (or
2910 * **AF_INET6**). It's advised to pass zero port (**sin_port**
2911 * or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like
2912 * behavior and lets the kernel efficiently pick up an unused
2913 * port as long as 4-tuple is unique. Passing non-zero port might
2914 * lead to degraded performance.
2916 * 0 on success, or a negative error in case of failure.
2918 * long bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
2920 * Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
2921 * possible to both shrink and grow the packet tail.
2922 * Shrink done via *delta* being a negative integer.
2924 * A call to this helper is susceptible to change the underlying
2925 * packet buffer. Therefore, at load time, all checks on pointers
2926 * previously done by the verifier are invalidated and must be
2927 * performed again, if the helper is used in combination with
2928 * direct packet access.
2930 * 0 on success, or a negative error in case of failure.
2932 * long bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
2934 * Retrieve the XFRM state (IP transform framework, see also
2935 * **ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
2937 * The retrieved value is stored in the **struct bpf_xfrm_state**
2938 * pointed by *xfrm_state* and of length *size*.
2940 * All values for *flags* are reserved for future usage, and must
2943 * This helper is available only if the kernel was compiled with
2944 * **CONFIG_XFRM** configuration option.
2946 * 0 on success, or a negative error in case of failure.
2948 * long bpf_get_stack(void *ctx, void *buf, u32 size, u64 flags)
2950 * Return a user or a kernel stack in bpf program provided buffer.
2951 * To achieve this, the helper needs *ctx*, which is a pointer
2952 * to the context on which the tracing program is executed.
2953 * To store the stacktrace, the bpf program provides *buf* with
2954 * a nonnegative *size*.
2956 * The last argument, *flags*, holds the number of stack frames to
2957 * skip (from 0 to 255), masked with
2958 * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
2959 * the following flags:
2961 * **BPF_F_USER_STACK**
2962 * Collect a user space stack instead of a kernel stack.
2963 * **BPF_F_USER_BUILD_ID**
2964 * Collect buildid+offset instead of ips for user stack,
2965 * only valid if **BPF_F_USER_STACK** is also specified.
2967 * **bpf_get_stack**\ () can collect up to
2968 * **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
2969 * to sufficient large buffer size. Note that
2970 * this limit can be controlled with the **sysctl** program, and
2971 * that it should be manually increased in order to profile long
2972 * user stacks (such as stacks for Java programs). To do so, use:
2976 * # sysctl kernel.perf_event_max_stack=<new value>
2978 * A non-negative value equal to or less than *size* on success,
2979 * or a negative error in case of failure.
2981 * long bpf_skb_load_bytes_relative(const void *skb, u32 offset, void *to, u32 len, u32 start_header)
2983 * This helper is similar to **bpf_skb_load_bytes**\ () in that
2984 * it provides an easy way to load *len* bytes from *offset*
2985 * from the packet associated to *skb*, into the buffer pointed
2986 * by *to*. The difference to **bpf_skb_load_bytes**\ () is that
2987 * a fifth argument *start_header* exists in order to select a
2988 * base offset to start from. *start_header* can be one of:
2990 * **BPF_HDR_START_MAC**
2991 * Base offset to load data from is *skb*'s mac header.
2992 * **BPF_HDR_START_NET**
2993 * Base offset to load data from is *skb*'s network header.
2995 * In general, "direct packet access" is the preferred method to
2996 * access packet data, however, this helper is in particular useful
2997 * in socket filters where *skb*\ **->data** does not always point
2998 * to the start of the mac header and where "direct packet access"
3001 * 0 on success, or a negative error in case of failure.
3003 * long bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
3005 * Do FIB lookup in kernel tables using parameters in *params*.
3006 * If lookup is successful and result shows packet is to be
3007 * forwarded, the neighbor tables are searched for the nexthop.
3008 * If successful (ie., FIB lookup shows forwarding and nexthop
3009 * is resolved), the nexthop address is returned in ipv4_dst
3010 * or ipv6_dst based on family, smac is set to mac address of
3011 * egress device, dmac is set to nexthop mac address, rt_metric
3012 * is set to metric from route (IPv4/IPv6 only), and ifindex
3013 * is set to the device index of the nexthop from the FIB lookup.
3015 * *plen* argument is the size of the passed in struct.
3016 * *flags* argument can be a combination of one or more of the
3019 * **BPF_FIB_LOOKUP_DIRECT**
3020 * Do a direct table lookup vs full lookup using FIB
3022 * **BPF_FIB_LOOKUP_OUTPUT**
3023 * Perform lookup from an egress perspective (default is
3026 * *ctx* is either **struct xdp_md** for XDP programs or
3027 * **struct sk_buff** tc cls_act programs.
3029 * * < 0 if any input argument is invalid
3030 * * 0 on success (packet is forwarded, nexthop neighbor exists)
3031 * * > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
3032 * packet is not forwarded or needs assist from full stack
3034 * If lookup fails with BPF_FIB_LKUP_RET_FRAG_NEEDED, then the MTU
3035 * was exceeded and output params->mtu_result contains the MTU.
3037 * long bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
3039 * Add an entry to, or update a sockhash *map* referencing sockets.
3040 * The *skops* is used as a new value for the entry associated to
3041 * *key*. *flags* is one of:
3044 * The entry for *key* must not exist in the map.
3046 * The entry for *key* must already exist in the map.
3048 * No condition on the existence of the entry for *key*.
3050 * If the *map* has eBPF programs (parser and verdict), those will
3051 * be inherited by the socket being added. If the socket is
3052 * already attached to eBPF programs, this results in an error.
3054 * 0 on success, or a negative error in case of failure.
3056 * long bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
3058 * This helper is used in programs implementing policies at the
3059 * socket level. If the message *msg* is allowed to pass (i.e. if
3060 * the verdict eBPF program returns **SK_PASS**), redirect it to
3061 * the socket referenced by *map* (of type
3062 * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
3063 * egress interfaces can be used for redirection. The
3064 * **BPF_F_INGRESS** value in *flags* is used to make the
3065 * distinction (ingress path is selected if the flag is present,
3066 * egress path otherwise). This is the only flag supported for now.
3068 * **SK_PASS** on success, or **SK_DROP** on error.
3070 * long bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
3072 * This helper is used in programs implementing policies at the
3073 * skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
3074 * if the verdict eBPF program returns **SK_PASS**), redirect it
3075 * to the socket referenced by *map* (of type
3076 * **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
3077 * egress interfaces can be used for redirection. The
3078 * **BPF_F_INGRESS** value in *flags* is used to make the
3079 * distinction (ingress path is selected if the flag is present,
3080 * egress otherwise). This is the only flag supported for now.
3082 * **SK_PASS** on success, or **SK_DROP** on error.
3084 * long bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
3086 * Encapsulate the packet associated to *skb* within a Layer 3
3087 * protocol header. This header is provided in the buffer at
3088 * address *hdr*, with *len* its size in bytes. *type* indicates
3089 * the protocol of the header and can be one of:
3091 * **BPF_LWT_ENCAP_SEG6**
3092 * IPv6 encapsulation with Segment Routing Header
3093 * (**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
3094 * the IPv6 header is computed by the kernel.
3095 * **BPF_LWT_ENCAP_SEG6_INLINE**
3096 * Only works if *skb* contains an IPv6 packet. Insert a
3097 * Segment Routing Header (**struct ipv6_sr_hdr**) inside
3099 * **BPF_LWT_ENCAP_IP**
3100 * IP encapsulation (GRE/GUE/IPIP/etc). The outer header
3101 * must be IPv4 or IPv6, followed by zero or more
3102 * additional headers, up to **LWT_BPF_MAX_HEADROOM**
3103 * total bytes in all prepended headers. Please note that
3104 * if **skb_is_gso**\ (*skb*) is true, no more than two
3105 * headers can be prepended, and the inner header, if
3106 * present, should be either GRE or UDP/GUE.
3108 * **BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs
3109 * of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can
3110 * be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and
3111 * **BPF_PROG_TYPE_LWT_XMIT**.
3113 * A call to this helper is susceptible to change the underlying
3114 * packet buffer. Therefore, at load time, all checks on pointers
3115 * previously done by the verifier are invalidated and must be
3116 * performed again, if the helper is used in combination with
3117 * direct packet access.
3119 * 0 on success, or a negative error in case of failure.
3121 * long bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
3123 * Store *len* bytes from address *from* into the packet
3124 * associated to *skb*, at *offset*. Only the flags, tag and TLVs
3125 * inside the outermost IPv6 Segment Routing Header can be
3126 * modified through this helper.
3128 * A call to this helper is susceptible to change the underlying
3129 * packet buffer. Therefore, at load time, all checks on pointers
3130 * previously done by the verifier are invalidated and must be
3131 * performed again, if the helper is used in combination with
3132 * direct packet access.
3134 * 0 on success, or a negative error in case of failure.
3136 * long bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
3138 * Adjust the size allocated to TLVs in the outermost IPv6
3139 * Segment Routing Header contained in the packet associated to
3140 * *skb*, at position *offset* by *delta* bytes. Only offsets
3141 * after the segments are accepted. *delta* can be as well
3142 * positive (growing) as negative (shrinking).
3144 * A call to this helper is susceptible to change the underlying
3145 * packet buffer. Therefore, at load time, all checks on pointers
3146 * previously done by the verifier are invalidated and must be
3147 * performed again, if the helper is used in combination with
3148 * direct packet access.
3150 * 0 on success, or a negative error in case of failure.
3152 * long bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
3154 * Apply an IPv6 Segment Routing action of type *action* to the
3155 * packet associated to *skb*. Each action takes a parameter
3156 * contained at address *param*, and of length *param_len* bytes.
3157 * *action* can be one of:
3159 * **SEG6_LOCAL_ACTION_END_X**
3160 * End.X action: Endpoint with Layer-3 cross-connect.
3161 * Type of *param*: **struct in6_addr**.
3162 * **SEG6_LOCAL_ACTION_END_T**
3163 * End.T action: Endpoint with specific IPv6 table lookup.
3164 * Type of *param*: **int**.
3165 * **SEG6_LOCAL_ACTION_END_B6**
3166 * End.B6 action: Endpoint bound to an SRv6 policy.
3167 * Type of *param*: **struct ipv6_sr_hdr**.
3168 * **SEG6_LOCAL_ACTION_END_B6_ENCAP**
3169 * End.B6.Encap action: Endpoint bound to an SRv6
3170 * encapsulation policy.
3171 * Type of *param*: **struct ipv6_sr_hdr**.
3173 * A call to this helper is susceptible to change the underlying
3174 * packet buffer. Therefore, at load time, all checks on pointers
3175 * previously done by the verifier are invalidated and must be
3176 * performed again, if the helper is used in combination with
3177 * direct packet access.
3179 * 0 on success, or a negative error in case of failure.
3181 * long bpf_rc_repeat(void *ctx)
3183 * This helper is used in programs implementing IR decoding, to
3184 * report a successfully decoded repeat key message. This delays
3185 * the generation of a key up event for previously generated
3188 * Some IR protocols like NEC have a special IR message for
3189 * repeating last button, for when a button is held down.
3191 * The *ctx* should point to the lirc sample as passed into
3194 * This helper is only available is the kernel was compiled with
3195 * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3200 * long bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
3202 * This helper is used in programs implementing IR decoding, to
3203 * report a successfully decoded key press with *scancode*,
3204 * *toggle* value in the given *protocol*. The scancode will be
3205 * translated to a keycode using the rc keymap, and reported as
3206 * an input key down event. After a period a key up event is
3207 * generated. This period can be extended by calling either
3208 * **bpf_rc_keydown**\ () again with the same values, or calling
3209 * **bpf_rc_repeat**\ ().
3211 * Some protocols include a toggle bit, in case the button was
3212 * released and pressed again between consecutive scancodes.
3214 * The *ctx* should point to the lirc sample as passed into
3217 * The *protocol* is the decoded protocol number (see
3218 * **enum rc_proto** for some predefined values).
3220 * This helper is only available is the kernel was compiled with
3221 * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3226 * u64 bpf_skb_cgroup_id(struct sk_buff *skb)
3228 * Return the cgroup v2 id of the socket associated with the *skb*.
3229 * This is roughly similar to the **bpf_get_cgroup_classid**\ ()
3230 * helper for cgroup v1 by providing a tag resp. identifier that
3231 * can be matched on or used for map lookups e.g. to implement
3232 * policy. The cgroup v2 id of a given path in the hierarchy is
3233 * exposed in user space through the f_handle API in order to get
3234 * to the same 64-bit id.
3236 * This helper can be used on TC egress path, but not on ingress,
3237 * and is available only if the kernel was compiled with the
3238 * **CONFIG_SOCK_CGROUP_DATA** configuration option.
3240 * The id is returned or 0 in case the id could not be retrieved.
3242 * u64 bpf_get_current_cgroup_id(void)
3244 * A 64-bit integer containing the current cgroup id based
3245 * on the cgroup within which the current task is running.
3247 * void *bpf_get_local_storage(void *map, u64 flags)
3249 * Get the pointer to the local storage area.
3250 * The type and the size of the local storage is defined
3251 * by the *map* argument.
3252 * The *flags* meaning is specific for each map type,
3253 * and has to be 0 for cgroup local storage.
3255 * Depending on the BPF program type, a local storage area
3256 * can be shared between multiple instances of the BPF program,
3257 * running simultaneously.
3259 * A user should care about the synchronization by himself.
3260 * For example, by using the **BPF_ATOMIC** instructions to alter
3263 * A pointer to the local storage area.
3265 * long bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
3267 * Select a **SO_REUSEPORT** socket from a
3268 * **BPF_MAP_TYPE_REUSEPORT_SOCKARRAY** *map*.
3269 * It checks the selected socket is matching the incoming
3270 * request in the socket buffer.
3272 * 0 on success, or a negative error in case of failure.
3274 * u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
3276 * Return id of cgroup v2 that is ancestor of cgroup associated
3277 * with the *skb* at the *ancestor_level*. The root cgroup is at
3278 * *ancestor_level* zero and each step down the hierarchy
3279 * increments the level. If *ancestor_level* == level of cgroup
3280 * associated with *skb*, then return value will be same as that
3281 * of **bpf_skb_cgroup_id**\ ().
3283 * The helper is useful to implement policies based on cgroups
3284 * that are upper in hierarchy than immediate cgroup associated
3287 * The format of returned id and helper limitations are same as in
3288 * **bpf_skb_cgroup_id**\ ().
3290 * The id is returned or 0 in case the id could not be retrieved.
3292 * struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3294 * Look for TCP socket matching *tuple*, optionally in a child
3295 * network namespace *netns*. The return value must be checked,
3296 * and if non-**NULL**, released via **bpf_sk_release**\ ().
3298 * The *ctx* should point to the context of the program, such as
3299 * the skb or socket (depending on the hook in use). This is used
3300 * to determine the base network namespace for the lookup.
3302 * *tuple_size* must be one of:
3304 * **sizeof**\ (*tuple*\ **->ipv4**)
3305 * Look for an IPv4 socket.
3306 * **sizeof**\ (*tuple*\ **->ipv6**)
3307 * Look for an IPv6 socket.
3309 * If the *netns* is a negative signed 32-bit integer, then the
3310 * socket lookup table in the netns associated with the *ctx*
3311 * will be used. For the TC hooks, this is the netns of the device
3312 * in the skb. For socket hooks, this is the netns of the socket.
3313 * If *netns* is any other signed 32-bit value greater than or
3314 * equal to zero then it specifies the ID of the netns relative to
3315 * the netns associated with the *ctx*. *netns* values beyond the
3316 * range of 32-bit integers are reserved for future use.
3318 * All values for *flags* are reserved for future usage, and must
3321 * This helper is available only if the kernel was compiled with
3322 * **CONFIG_NET** configuration option.
3324 * Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3325 * For sockets with reuseport option, the **struct bpf_sock**
3326 * result is from *reuse*\ **->socks**\ [] using the hash of the
3329 * struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3331 * Look for UDP socket matching *tuple*, optionally in a child
3332 * network namespace *netns*. The return value must be checked,
3333 * and if non-**NULL**, released via **bpf_sk_release**\ ().
3335 * The *ctx* should point to the context of the program, such as
3336 * the skb or socket (depending on the hook in use). This is used
3337 * to determine the base network namespace for the lookup.
3339 * *tuple_size* must be one of:
3341 * **sizeof**\ (*tuple*\ **->ipv4**)
3342 * Look for an IPv4 socket.
3343 * **sizeof**\ (*tuple*\ **->ipv6**)
3344 * Look for an IPv6 socket.
3346 * If the *netns* is a negative signed 32-bit integer, then the
3347 * socket lookup table in the netns associated with the *ctx*
3348 * will be used. For the TC hooks, this is the netns of the device
3349 * in the skb. For socket hooks, this is the netns of the socket.
3350 * If *netns* is any other signed 32-bit value greater than or
3351 * equal to zero then it specifies the ID of the netns relative to
3352 * the netns associated with the *ctx*. *netns* values beyond the
3353 * range of 32-bit integers are reserved for future use.
3355 * All values for *flags* are reserved for future usage, and must
3358 * This helper is available only if the kernel was compiled with
3359 * **CONFIG_NET** configuration option.
3361 * Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3362 * For sockets with reuseport option, the **struct bpf_sock**
3363 * result is from *reuse*\ **->socks**\ [] using the hash of the
3366 * long bpf_sk_release(void *sock)
3368 * Release the reference held by *sock*. *sock* must be a
3369 * non-**NULL** pointer that was returned from
3370 * **bpf_sk_lookup_xxx**\ ().
3372 * 0 on success, or a negative error in case of failure.
3374 * long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
3376 * Push an element *value* in *map*. *flags* is one of:
3379 * If the queue/stack is full, the oldest element is
3380 * removed to make room for this.
3382 * 0 on success, or a negative error in case of failure.
3384 * long bpf_map_pop_elem(struct bpf_map *map, void *value)
3386 * Pop an element from *map*.
3388 * 0 on success, or a negative error in case of failure.
3390 * long bpf_map_peek_elem(struct bpf_map *map, void *value)
3392 * Get an element from *map* without removing it.
3394 * 0 on success, or a negative error in case of failure.
3396 * long bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3398 * For socket policies, insert *len* bytes into *msg* at offset
3401 * If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
3402 * *msg* it may want to insert metadata or options into the *msg*.
3403 * This can later be read and used by any of the lower layer BPF
3406 * This helper may fail if under memory pressure (a malloc
3407 * fails) in these cases BPF programs will get an appropriate
3408 * error and BPF programs will need to handle them.
3410 * 0 on success, or a negative error in case of failure.
3412 * long bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
3414 * Will remove *len* bytes from a *msg* starting at byte *start*.
3415 * This may result in **ENOMEM** errors under certain situations if
3416 * an allocation and copy are required due to a full ring buffer.
3417 * However, the helper will try to avoid doing the allocation
3418 * if possible. Other errors can occur if input parameters are
3419 * invalid either due to *start* byte not being valid part of *msg*
3420 * payload and/or *pop* value being to large.
3422 * 0 on success, or a negative error in case of failure.
3424 * long bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
3426 * This helper is used in programs implementing IR decoding, to
3427 * report a successfully decoded pointer movement.
3429 * The *ctx* should point to the lirc sample as passed into
3432 * This helper is only available is the kernel was compiled with
3433 * the **CONFIG_BPF_LIRC_MODE2** configuration option set to
3438 * long bpf_spin_lock(struct bpf_spin_lock *lock)
3440 * Acquire a spinlock represented by the pointer *lock*, which is
3441 * stored as part of a value of a map. Taking the lock allows to
3442 * safely update the rest of the fields in that value. The
3443 * spinlock can (and must) later be released with a call to
3444 * **bpf_spin_unlock**\ (\ *lock*\ ).
3446 * Spinlocks in BPF programs come with a number of restrictions
3449 * * **bpf_spin_lock** objects are only allowed inside maps of
3450 * types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
3451 * list could be extended in the future).
3452 * * BTF description of the map is mandatory.
3453 * * The BPF program can take ONE lock at a time, since taking two
3454 * or more could cause dead locks.
3455 * * Only one **struct bpf_spin_lock** is allowed per map element.
3456 * * When the lock is taken, calls (either BPF to BPF or helpers)
3458 * * The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
3459 * allowed inside a spinlock-ed region.
3460 * * The BPF program MUST call **bpf_spin_unlock**\ () to release
3461 * the lock, on all execution paths, before it returns.
3462 * * The BPF program can access **struct bpf_spin_lock** only via
3463 * the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
3464 * helpers. Loading or storing data into the **struct
3465 * bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
3466 * * To use the **bpf_spin_lock**\ () helper, the BTF description
3467 * of the map value must be a struct and have **struct
3468 * bpf_spin_lock** *anyname*\ **;** field at the top level.
3469 * Nested lock inside another struct is not allowed.
3470 * * The **struct bpf_spin_lock** *lock* field in a map value must
3471 * be aligned on a multiple of 4 bytes in that value.
3472 * * Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
3473 * the **bpf_spin_lock** field to user space.
3474 * * Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
3475 * a BPF program, do not update the **bpf_spin_lock** field.
3476 * * **bpf_spin_lock** cannot be on the stack or inside a
3477 * networking packet (it can only be inside of a map values).
3478 * * **bpf_spin_lock** is available to root only.
3479 * * Tracing programs and socket filter programs cannot use
3480 * **bpf_spin_lock**\ () due to insufficient preemption checks
3481 * (but this may change in the future).
3482 * * **bpf_spin_lock** is not allowed in inner maps of map-in-map.
3486 * long bpf_spin_unlock(struct bpf_spin_lock *lock)
3488 * Release the *lock* previously locked by a call to
3489 * **bpf_spin_lock**\ (\ *lock*\ ).
3493 * struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
3495 * This helper gets a **struct bpf_sock** pointer such
3496 * that all the fields in this **bpf_sock** can be accessed.
3498 * A **struct bpf_sock** pointer on success, or **NULL** in
3501 * struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
3503 * This helper gets a **struct bpf_tcp_sock** pointer from a
3504 * **struct bpf_sock** pointer.
3506 * A **struct bpf_tcp_sock** pointer on success, or **NULL** in
3509 * long bpf_skb_ecn_set_ce(struct sk_buff *skb)
3511 * Set ECN (Explicit Congestion Notification) field of IP header
3512 * to **CE** (Congestion Encountered) if current value is **ECT**
3513 * (ECN Capable Transport). Otherwise, do nothing. Works with IPv6
3516 * 1 if the **CE** flag is set (either by the current helper call
3517 * or because it was already present), 0 if it is not set.
3519 * struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)
3521 * Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
3522 * **bpf_sk_release**\ () is unnecessary and not allowed.
3524 * A **struct bpf_sock** pointer on success, or **NULL** in
3527 * struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
3529 * Look for TCP socket matching *tuple*, optionally in a child
3530 * network namespace *netns*. The return value must be checked,
3531 * and if non-**NULL**, released via **bpf_sk_release**\ ().
3533 * This function is identical to **bpf_sk_lookup_tcp**\ (), except
3534 * that it also returns timewait or request sockets. Use
3535 * **bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the
3538 * This helper is available only if the kernel was compiled with
3539 * **CONFIG_NET** configuration option.
3541 * Pointer to **struct bpf_sock**, or **NULL** in case of failure.
3542 * For sockets with reuseport option, the **struct bpf_sock**
3543 * result is from *reuse*\ **->socks**\ [] using the hash of the
3546 * long bpf_tcp_check_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3548 * Check whether *iph* and *th* contain a valid SYN cookie ACK for
3549 * the listening socket in *sk*.
3551 * *iph* points to the start of the IPv4 or IPv6 header, while
3552 * *iph_len* contains **sizeof**\ (**struct iphdr**) or
3553 * **sizeof**\ (**struct ip6hdr**).
3555 * *th* points to the start of the TCP header, while *th_len*
3556 * contains **sizeof**\ (**struct tcphdr**).
3558 * 0 if *iph* and *th* are a valid SYN cookie ACK, or a negative
3561 * long bpf_sysctl_get_name(struct bpf_sysctl *ctx, char *buf, size_t buf_len, u64 flags)
3563 * Get name of sysctl in /proc/sys/ and copy it into provided by
3564 * program buffer *buf* of size *buf_len*.
3566 * The buffer is always NUL terminated, unless it's zero-sized.
3568 * If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is
3569 * copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name
3570 * only (e.g. "tcp_mem").
3572 * Number of character copied (not including the trailing NUL).
3574 * **-E2BIG** if the buffer wasn't big enough (*buf* will contain
3575 * truncated name in this case).
3577 * long bpf_sysctl_get_current_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
3579 * Get current value of sysctl as it is presented in /proc/sys
3580 * (incl. newline, etc), and copy it as a string into provided
3581 * by program buffer *buf* of size *buf_len*.
3583 * The whole value is copied, no matter what file position user
3584 * space issued e.g. sys_read at.
3586 * The buffer is always NUL terminated, unless it's zero-sized.
3588 * Number of character copied (not including the trailing NUL).
3590 * **-E2BIG** if the buffer wasn't big enough (*buf* will contain
3591 * truncated name in this case).
3593 * **-EINVAL** if current value was unavailable, e.g. because
3594 * sysctl is uninitialized and read returns -EIO for it.
3596 * long bpf_sysctl_get_new_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
3598 * Get new value being written by user space to sysctl (before
3599 * the actual write happens) and copy it as a string into
3600 * provided by program buffer *buf* of size *buf_len*.
3602 * User space may write new value at file position > 0.
3604 * The buffer is always NUL terminated, unless it's zero-sized.
3606 * Number of character copied (not including the trailing NUL).
3608 * **-E2BIG** if the buffer wasn't big enough (*buf* will contain
3609 * truncated name in this case).
3611 * **-EINVAL** if sysctl is being read.
3613 * long bpf_sysctl_set_new_value(struct bpf_sysctl *ctx, const char *buf, size_t buf_len)
3615 * Override new value being written by user space to sysctl with
3616 * value provided by program in buffer *buf* of size *buf_len*.
3618 * *buf* should contain a string in same form as provided by user
3619 * space on sysctl write.
3621 * User space may write new value at file position > 0. To override
3622 * the whole sysctl value file position should be set to zero.
3626 * **-E2BIG** if the *buf_len* is too big.
3628 * **-EINVAL** if sysctl is being read.
3630 * long bpf_strtol(const char *buf, size_t buf_len, u64 flags, long *res)
3632 * Convert the initial part of the string from buffer *buf* of
3633 * size *buf_len* to a long integer according to the given base
3634 * and save the result in *res*.
3636 * The string may begin with an arbitrary amount of white space
3637 * (as determined by **isspace**\ (3)) followed by a single
3638 * optional '**-**' sign.
3640 * Five least significant bits of *flags* encode base, other bits
3641 * are currently unused.
3643 * Base must be either 8, 10, 16 or 0 to detect it automatically
3644 * similar to user space **strtol**\ (3).
3646 * Number of characters consumed on success. Must be positive but
3647 * no more than *buf_len*.
3649 * **-EINVAL** if no valid digits were found or unsupported base
3652 * **-ERANGE** if resulting value was out of range.
3654 * long bpf_strtoul(const char *buf, size_t buf_len, u64 flags, unsigned long *res)
3656 * Convert the initial part of the string from buffer *buf* of
3657 * size *buf_len* to an unsigned long integer according to the
3658 * given base and save the result in *res*.
3660 * The string may begin with an arbitrary amount of white space
3661 * (as determined by **isspace**\ (3)).
3663 * Five least significant bits of *flags* encode base, other bits
3664 * are currently unused.
3666 * Base must be either 8, 10, 16 or 0 to detect it automatically
3667 * similar to user space **strtoul**\ (3).
3669 * Number of characters consumed on success. Must be positive but
3670 * no more than *buf_len*.
3672 * **-EINVAL** if no valid digits were found or unsupported base
3675 * **-ERANGE** if resulting value was out of range.
3677 * void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags)
3679 * Get a bpf-local-storage from a *sk*.
3681 * Logically, it could be thought of getting the value from
3682 * a *map* with *sk* as the **key**. From this
3683 * perspective, the usage is not much different from
3684 * **bpf_map_lookup_elem**\ (*map*, **&**\ *sk*) except this
3685 * helper enforces the key must be a full socket and the map must
3686 * be a **BPF_MAP_TYPE_SK_STORAGE** also.
3688 * Underneath, the value is stored locally at *sk* instead of
3689 * the *map*. The *map* is used as the bpf-local-storage
3690 * "type". The bpf-local-storage "type" (i.e. the *map*) is
3691 * searched against all bpf-local-storages residing at *sk*.
3693 * *sk* is a kernel **struct sock** pointer for LSM program.
3694 * *sk* is a **struct bpf_sock** pointer for other program types.
3696 * An optional *flags* (**BPF_SK_STORAGE_GET_F_CREATE**) can be
3697 * used such that a new bpf-local-storage will be
3698 * created if one does not exist. *value* can be used
3699 * together with **BPF_SK_STORAGE_GET_F_CREATE** to specify
3700 * the initial value of a bpf-local-storage. If *value* is
3701 * **NULL**, the new bpf-local-storage will be zero initialized.
3703 * A bpf-local-storage pointer is returned on success.
3705 * **NULL** if not found or there was an error in adding
3706 * a new bpf-local-storage.
3708 * long bpf_sk_storage_delete(struct bpf_map *map, void *sk)
3710 * Delete a bpf-local-storage from a *sk*.
3714 * **-ENOENT** if the bpf-local-storage cannot be found.
3715 * **-EINVAL** if sk is not a fullsock (e.g. a request_sock).
3717 * long bpf_send_signal(u32 sig)
3719 * Send signal *sig* to the process of the current task.
3720 * The signal may be delivered to any of this process's threads.
3722 * 0 on success or successfully queued.
3724 * **-EBUSY** if work queue under nmi is full.
3726 * **-EINVAL** if *sig* is invalid.
3728 * **-EPERM** if no permission to send the *sig*.
3730 * **-EAGAIN** if bpf program can try again.
3732 * s64 bpf_tcp_gen_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
3734 * Try to issue a SYN cookie for the packet with corresponding
3735 * IP/TCP headers, *iph* and *th*, on the listening socket in *sk*.
3737 * *iph* points to the start of the IPv4 or IPv6 header, while
3738 * *iph_len* contains **sizeof**\ (**struct iphdr**) or
3739 * **sizeof**\ (**struct ip6hdr**).
3741 * *th* points to the start of the TCP header, while *th_len*
3742 * contains the length of the TCP header.
3744 * On success, lower 32 bits hold the generated SYN cookie in
3745 * followed by 16 bits which hold the MSS value for that cookie,
3746 * and the top 16 bits are unused.
3748 * On failure, the returned value is one of the following:
3750 * **-EINVAL** SYN cookie cannot be issued due to error
3752 * **-ENOENT** SYN cookie should not be issued (no SYN flood)
3754 * **-EOPNOTSUPP** kernel configuration does not enable SYN cookies
3756 * **-EPROTONOSUPPORT** IP packet version is not 4 or 6
3758 * long bpf_skb_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
3760 * Write raw *data* blob into a special BPF perf event held by
3761 * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
3762 * event must have the following attributes: **PERF_SAMPLE_RAW**
3763 * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
3764 * **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
3766 * The *flags* are used to indicate the index in *map* for which
3767 * the value must be put, masked with **BPF_F_INDEX_MASK**.
3768 * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
3769 * to indicate that the index of the current CPU core should be
3772 * The value to write, of *size*, is passed through eBPF stack and
3773 * pointed by *data*.
3775 * *ctx* is a pointer to in-kernel struct sk_buff.
3777 * This helper is similar to **bpf_perf_event_output**\ () but
3778 * restricted to raw_tracepoint bpf programs.
3780 * 0 on success, or a negative error in case of failure.
3782 * long bpf_probe_read_user(void *dst, u32 size, const void *unsafe_ptr)
3784 * Safely attempt to read *size* bytes from user space address
3785 * *unsafe_ptr* and store the data in *dst*.
3787 * 0 on success, or a negative error in case of failure.
3789 * long bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
3791 * Safely attempt to read *size* bytes from kernel space address
3792 * *unsafe_ptr* and store the data in *dst*.
3794 * 0 on success, or a negative error in case of failure.
3796 * long bpf_probe_read_user_str(void *dst, u32 size, const void *unsafe_ptr)
3798 * Copy a NUL terminated string from an unsafe user address
3799 * *unsafe_ptr* to *dst*. The *size* should include the
3800 * terminating NUL byte. In case the string length is smaller than
3801 * *size*, the target is not padded with further NUL bytes. If the
3802 * string length is larger than *size*, just *size*-1 bytes are
3803 * copied and the last byte is set to NUL.
3805 * On success, returns the number of bytes that were written,
3806 * including the terminal NUL. This makes this helper useful in
3807 * tracing programs for reading strings, and more importantly to
3808 * get its length at runtime. See the following snippet:
3812 * SEC("kprobe/sys_open")
3813 * void bpf_sys_open(struct pt_regs *ctx)
3815 * char buf[PATHLEN]; // PATHLEN is defined to 256
3816 * int res = bpf_probe_read_user_str(buf, sizeof(buf),
3819 * // Consume buf, for example push it to
3820 * // userspace via bpf_perf_event_output(); we
3821 * // can use res (the string length) as event
3822 * // size, after checking its boundaries.
3825 * In comparison, using **bpf_probe_read_user**\ () helper here
3826 * instead to read the string would require to estimate the length
3827 * at compile time, and would often result in copying more memory
3830 * Another useful use case is when parsing individual process
3831 * arguments or individual environment variables navigating
3832 * *current*\ **->mm->arg_start** and *current*\
3833 * **->mm->env_start**: using this helper and the return value,
3834 * one can quickly iterate at the right offset of the memory area.
3836 * On success, the strictly positive length of the output string,
3837 * including the trailing NUL character. On error, a negative
3840 * long bpf_probe_read_kernel_str(void *dst, u32 size, const void *unsafe_ptr)
3842 * Copy a NUL terminated string from an unsafe kernel address *unsafe_ptr*
3843 * to *dst*. Same semantics as with **bpf_probe_read_user_str**\ () apply.
3845 * On success, the strictly positive length of the string, including
3846 * the trailing NUL character. On error, a negative value.
3848 * long bpf_tcp_send_ack(void *tp, u32 rcv_nxt)
3850 * Send out a tcp-ack. *tp* is the in-kernel struct **tcp_sock**.
3851 * *rcv_nxt* is the ack_seq to be sent out.
3853 * 0 on success, or a negative error in case of failure.
3855 * long bpf_send_signal_thread(u32 sig)
3857 * Send signal *sig* to the thread corresponding to the current task.
3859 * 0 on success or successfully queued.
3861 * **-EBUSY** if work queue under nmi is full.
3863 * **-EINVAL** if *sig* is invalid.
3865 * **-EPERM** if no permission to send the *sig*.
3867 * **-EAGAIN** if bpf program can try again.
3869 * u64 bpf_jiffies64(void)
3871 * Obtain the 64bit jiffies
3873 * The 64 bit jiffies
3875 * long bpf_read_branch_records(struct bpf_perf_event_data *ctx, void *buf, u32 size, u64 flags)
3877 * For an eBPF program attached to a perf event, retrieve the
3878 * branch records (**struct perf_branch_entry**) associated to *ctx*
3879 * and store it in the buffer pointed by *buf* up to size
3882 * On success, number of bytes written to *buf*. On error, a
3885 * The *flags* can be set to **BPF_F_GET_BRANCH_RECORDS_SIZE** to
3886 * instead return the number of bytes required to store all the
3887 * branch entries. If this flag is set, *buf* may be NULL.
3889 * **-EINVAL** if arguments invalid or **size** not a multiple
3890 * of **sizeof**\ (**struct perf_branch_entry**\ ).
3892 * **-ENOENT** if architecture does not support branch records.
3894 * long bpf_get_ns_current_pid_tgid(u64 dev, u64 ino, struct bpf_pidns_info *nsdata, u32 size)
3896 * Returns 0 on success, values for *pid* and *tgid* as seen from the current
3897 * *namespace* will be returned in *nsdata*.
3899 * 0 on success, or one of the following in case of failure:
3901 * **-EINVAL** if dev and inum supplied don't match dev_t and inode number
3902 * with nsfs of current task, or if dev conversion to dev_t lost high bits.
3904 * **-ENOENT** if pidns does not exists for the current task.
3906 * long bpf_xdp_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
3908 * Write raw *data* blob into a special BPF perf event held by
3909 * *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
3910 * event must have the following attributes: **PERF_SAMPLE_RAW**
3911 * as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
3912 * **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
3914 * The *flags* are used to indicate the index in *map* for which
3915 * the value must be put, masked with **BPF_F_INDEX_MASK**.
3916 * Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
3917 * to indicate that the index of the current CPU core should be
3920 * The value to write, of *size*, is passed through eBPF stack and
3921 * pointed by *data*.
3923 * *ctx* is a pointer to in-kernel struct xdp_buff.
3925 * This helper is similar to **bpf_perf_eventoutput**\ () but
3926 * restricted to raw_tracepoint bpf programs.
3928 * 0 on success, or a negative error in case of failure.
3930 * u64 bpf_get_netns_cookie(void *ctx)
3932 * Retrieve the cookie (generated by the kernel) of the network
3933 * namespace the input *ctx* is associated with. The network
3934 * namespace cookie remains stable for its lifetime and provides
3935 * a global identifier that can be assumed unique. If *ctx* is
3936 * NULL, then the helper returns the cookie for the initial
3937 * network namespace. The cookie itself is very similar to that
3938 * of **bpf_get_socket_cookie**\ () helper, but for network
3939 * namespaces instead of sockets.
3941 * A 8-byte long opaque number.
3943 * u64 bpf_get_current_ancestor_cgroup_id(int ancestor_level)
3945 * Return id of cgroup v2 that is ancestor of the cgroup associated
3946 * with the current task at the *ancestor_level*. The root cgroup
3947 * is at *ancestor_level* zero and each step down the hierarchy
3948 * increments the level. If *ancestor_level* == level of cgroup
3949 * associated with the current task, then return value will be the
3950 * same as that of **bpf_get_current_cgroup_id**\ ().
3952 * The helper is useful to implement policies based on cgroups
3953 * that are upper in hierarchy than immediate cgroup associated
3954 * with the current task.
3956 * The format of returned id and helper limitations are same as in
3957 * **bpf_get_current_cgroup_id**\ ().
3959 * The id is returned or 0 in case the id could not be retrieved.
3961 * long bpf_sk_assign(struct sk_buff *skb, void *sk, u64 flags)
3963 * Helper is overloaded depending on BPF program type. This
3964 * description applies to **BPF_PROG_TYPE_SCHED_CLS** and
3965 * **BPF_PROG_TYPE_SCHED_ACT** programs.
3967 * Assign the *sk* to the *skb*. When combined with appropriate
3968 * routing configuration to receive the packet towards the socket,
3969 * will cause *skb* to be delivered to the specified socket.
3970 * Subsequent redirection of *skb* via **bpf_redirect**\ (),
3971 * **bpf_clone_redirect**\ () or other methods outside of BPF may
3972 * interfere with successful delivery to the socket.
3974 * This operation is only valid from TC ingress path.
3976 * The *flags* argument must be zero.
3978 * 0 on success, or a negative error in case of failure:
3980 * **-EINVAL** if specified *flags* are not supported.
3982 * **-ENOENT** if the socket is unavailable for assignment.
3984 * **-ENETUNREACH** if the socket is unreachable (wrong netns).
3986 * **-EOPNOTSUPP** if the operation is not supported, for example
3987 * a call from outside of TC ingress.
3989 * **-ESOCKTNOSUPPORT** if the socket type is not supported
3992 * long bpf_sk_assign(struct bpf_sk_lookup *ctx, struct bpf_sock *sk, u64 flags)
3994 * Helper is overloaded depending on BPF program type. This
3995 * description applies to **BPF_PROG_TYPE_SK_LOOKUP** programs.
3997 * Select the *sk* as a result of a socket lookup.
3999 * For the operation to succeed passed socket must be compatible
4000 * with the packet description provided by the *ctx* object.
4002 * L4 protocol (**IPPROTO_TCP** or **IPPROTO_UDP**) must
4003 * be an exact match. While IP family (**AF_INET** or
4004 * **AF_INET6**) must be compatible, that is IPv6 sockets
4005 * that are not v6-only can be selected for IPv4 packets.
4007 * Only TCP listeners and UDP unconnected sockets can be
4008 * selected. *sk* can also be NULL to reset any previous
4011 * *flags* argument can combination of following values:
4013 * * **BPF_SK_LOOKUP_F_REPLACE** to override the previous
4014 * socket selection, potentially done by a BPF program
4015 * that ran before us.
4017 * * **BPF_SK_LOOKUP_F_NO_REUSEPORT** to skip
4018 * load-balancing within reuseport group for the socket
4021 * On success *ctx->sk* will point to the selected socket.
4024 * 0 on success, or a negative errno in case of failure.
4026 * * **-EAFNOSUPPORT** if socket family (*sk->family*) is
4027 * not compatible with packet family (*ctx->family*).
4029 * * **-EEXIST** if socket has been already selected,
4030 * potentially by another program, and
4031 * **BPF_SK_LOOKUP_F_REPLACE** flag was not specified.
4033 * * **-EINVAL** if unsupported flags were specified.
4035 * * **-EPROTOTYPE** if socket L4 protocol
4036 * (*sk->protocol*) doesn't match packet protocol
4037 * (*ctx->protocol*).
4039 * * **-ESOCKTNOSUPPORT** if socket is not in allowed
4040 * state (TCP listening or UDP unconnected).
4042 * u64 bpf_ktime_get_boot_ns(void)
4044 * Return the time elapsed since system boot, in nanoseconds.
4045 * Does include the time the system was suspended.
4046 * See: **clock_gettime**\ (**CLOCK_BOOTTIME**)
4050 * long bpf_seq_printf(struct seq_file *m, const char *fmt, u32 fmt_size, const void *data, u32 data_len)
4052 * **bpf_seq_printf**\ () uses seq_file **seq_printf**\ () to print
4053 * out the format string.
4054 * The *m* represents the seq_file. The *fmt* and *fmt_size* are for
4055 * the format string itself. The *data* and *data_len* are format string
4056 * arguments. The *data* are a **u64** array and corresponding format string
4057 * values are stored in the array. For strings and pointers where pointees
4058 * are accessed, only the pointer values are stored in the *data* array.
4059 * The *data_len* is the size of *data* in bytes - must be a multiple of 8.
4061 * Formats **%s**, **%p{i,I}{4,6}** requires to read kernel memory.
4062 * Reading kernel memory may fail due to either invalid address or
4063 * valid address but requiring a major memory fault. If reading kernel memory
4064 * fails, the string for **%s** will be an empty string, and the ip
4065 * address for **%p{i,I}{4,6}** will be 0. Not returning error to
4066 * bpf program is consistent with what **bpf_trace_printk**\ () does for now.
4068 * 0 on success, or a negative error in case of failure:
4070 * **-EBUSY** if per-CPU memory copy buffer is busy, can try again
4071 * by returning 1 from bpf program.
4073 * **-EINVAL** if arguments are invalid, or if *fmt* is invalid/unsupported.
4075 * **-E2BIG** if *fmt* contains too many format specifiers.
4077 * **-EOVERFLOW** if an overflow happened: The same object will be tried again.
4079 * long bpf_seq_write(struct seq_file *m, const void *data, u32 len)
4081 * **bpf_seq_write**\ () uses seq_file **seq_write**\ () to write the data.
4082 * The *m* represents the seq_file. The *data* and *len* represent the
4083 * data to write in bytes.
4085 * 0 on success, or a negative error in case of failure:
4087 * **-EOVERFLOW** if an overflow happened: The same object will be tried again.
4089 * u64 bpf_sk_cgroup_id(void *sk)
4091 * Return the cgroup v2 id of the socket *sk*.
4093 * *sk* must be a non-**NULL** pointer to a socket, e.g. one
4094 * returned from **bpf_sk_lookup_xxx**\ (),
4095 * **bpf_sk_fullsock**\ (), etc. The format of returned id is
4096 * same as in **bpf_skb_cgroup_id**\ ().
4098 * This helper is available only if the kernel was compiled with
4099 * the **CONFIG_SOCK_CGROUP_DATA** configuration option.
4101 * The id is returned or 0 in case the id could not be retrieved.
4103 * u64 bpf_sk_ancestor_cgroup_id(void *sk, int ancestor_level)
4105 * Return id of cgroup v2 that is ancestor of cgroup associated
4106 * with the *sk* at the *ancestor_level*. The root cgroup is at
4107 * *ancestor_level* zero and each step down the hierarchy
4108 * increments the level. If *ancestor_level* == level of cgroup
4109 * associated with *sk*, then return value will be same as that
4110 * of **bpf_sk_cgroup_id**\ ().
4112 * The helper is useful to implement policies based on cgroups
4113 * that are upper in hierarchy than immediate cgroup associated
4116 * The format of returned id and helper limitations are same as in
4117 * **bpf_sk_cgroup_id**\ ().
4119 * The id is returned or 0 in case the id could not be retrieved.
4121 * long bpf_ringbuf_output(void *ringbuf, void *data, u64 size, u64 flags)
4123 * Copy *size* bytes from *data* into a ring buffer *ringbuf*.
4124 * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4125 * of new data availability is sent.
4126 * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4127 * of new data availability is sent unconditionally.
4128 * If **0** is specified in *flags*, an adaptive notification
4129 * of new data availability is sent.
4131 * An adaptive notification is a notification sent whenever the user-space
4132 * process has caught up and consumed all available payloads. In case the user-space
4133 * process is still processing a previous payload, then no notification is needed
4134 * as it will process the newly added payload automatically.
4136 * 0 on success, or a negative error in case of failure.
4138 * void *bpf_ringbuf_reserve(void *ringbuf, u64 size, u64 flags)
4140 * Reserve *size* bytes of payload in a ring buffer *ringbuf*.
4141 * *flags* must be 0.
4143 * Valid pointer with *size* bytes of memory available; NULL,
4146 * void bpf_ringbuf_submit(void *data, u64 flags)
4148 * Submit reserved ring buffer sample, pointed to by *data*.
4149 * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4150 * of new data availability is sent.
4151 * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4152 * of new data availability is sent unconditionally.
4153 * If **0** is specified in *flags*, an adaptive notification
4154 * of new data availability is sent.
4156 * See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4158 * Nothing. Always succeeds.
4160 * void bpf_ringbuf_discard(void *data, u64 flags)
4162 * Discard reserved ring buffer sample, pointed to by *data*.
4163 * If **BPF_RB_NO_WAKEUP** is specified in *flags*, no notification
4164 * of new data availability is sent.
4165 * If **BPF_RB_FORCE_WAKEUP** is specified in *flags*, notification
4166 * of new data availability is sent unconditionally.
4167 * If **0** is specified in *flags*, an adaptive notification
4168 * of new data availability is sent.
4170 * See 'bpf_ringbuf_output()' for the definition of adaptive notification.
4172 * Nothing. Always succeeds.
4174 * u64 bpf_ringbuf_query(void *ringbuf, u64 flags)
4176 * Query various characteristics of provided ring buffer. What
4177 * exactly is queries is determined by *flags*:
4179 * * **BPF_RB_AVAIL_DATA**: Amount of data not yet consumed.
4180 * * **BPF_RB_RING_SIZE**: The size of ring buffer.
4181 * * **BPF_RB_CONS_POS**: Consumer position (can wrap around).
4182 * * **BPF_RB_PROD_POS**: Producer(s) position (can wrap around).
4184 * Data returned is just a momentary snapshot of actual values
4185 * and could be inaccurate, so this facility should be used to
4186 * power heuristics and for reporting, not to make 100% correct
4189 * Requested value, or 0, if *flags* are not recognized.
4191 * long bpf_csum_level(struct sk_buff *skb, u64 level)
4193 * Change the skbs checksum level by one layer up or down, or
4194 * reset it entirely to none in order to have the stack perform
4195 * checksum validation. The level is applicable to the following
4196 * protocols: TCP, UDP, GRE, SCTP, FCOE. For example, a decap of
4197 * | ETH | IP | UDP | GUE | IP | TCP | into | ETH | IP | TCP |
4198 * through **bpf_skb_adjust_room**\ () helper with passing in
4199 * **BPF_F_ADJ_ROOM_NO_CSUM_RESET** flag would require one call
4200 * to **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_DEC** since
4201 * the UDP header is removed. Similarly, an encap of the latter
4202 * into the former could be accompanied by a helper call to
4203 * **bpf_csum_level**\ () with **BPF_CSUM_LEVEL_INC** if the
4204 * skb is still intended to be processed in higher layers of the
4205 * stack instead of just egressing at tc.
4207 * There are three supported level settings at this time:
4209 * * **BPF_CSUM_LEVEL_INC**: Increases skb->csum_level for skbs
4210 * with CHECKSUM_UNNECESSARY.
4211 * * **BPF_CSUM_LEVEL_DEC**: Decreases skb->csum_level for skbs
4212 * with CHECKSUM_UNNECESSARY.
4213 * * **BPF_CSUM_LEVEL_RESET**: Resets skb->csum_level to 0 and
4214 * sets CHECKSUM_NONE to force checksum validation by the stack.
4215 * * **BPF_CSUM_LEVEL_QUERY**: No-op, returns the current
4218 * 0 on success, or a negative error in case of failure. In the
4219 * case of **BPF_CSUM_LEVEL_QUERY**, the current skb->csum_level
4220 * is returned or the error code -EACCES in case the skb is not
4221 * subject to CHECKSUM_UNNECESSARY.
4223 * struct tcp6_sock *bpf_skc_to_tcp6_sock(void *sk)
4225 * Dynamically cast a *sk* pointer to a *tcp6_sock* pointer.
4227 * *sk* if casting is valid, or **NULL** otherwise.
4229 * struct tcp_sock *bpf_skc_to_tcp_sock(void *sk)
4231 * Dynamically cast a *sk* pointer to a *tcp_sock* pointer.
4233 * *sk* if casting is valid, or **NULL** otherwise.
4235 * struct tcp_timewait_sock *bpf_skc_to_tcp_timewait_sock(void *sk)
4237 * Dynamically cast a *sk* pointer to a *tcp_timewait_sock* pointer.
4239 * *sk* if casting is valid, or **NULL** otherwise.
4241 * struct tcp_request_sock *bpf_skc_to_tcp_request_sock(void *sk)
4243 * Dynamically cast a *sk* pointer to a *tcp_request_sock* pointer.
4245 * *sk* if casting is valid, or **NULL** otherwise.
4247 * struct udp6_sock *bpf_skc_to_udp6_sock(void *sk)
4249 * Dynamically cast a *sk* pointer to a *udp6_sock* pointer.
4251 * *sk* if casting is valid, or **NULL** otherwise.
4253 * long bpf_get_task_stack(struct task_struct *task, void *buf, u32 size, u64 flags)
4255 * Return a user or a kernel stack in bpf program provided buffer.
4256 * To achieve this, the helper needs *task*, which is a valid
4257 * pointer to **struct task_struct**. To store the stacktrace, the
4258 * bpf program provides *buf* with a nonnegative *size*.
4260 * The last argument, *flags*, holds the number of stack frames to
4261 * skip (from 0 to 255), masked with
4262 * **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
4263 * the following flags:
4265 * **BPF_F_USER_STACK**
4266 * Collect a user space stack instead of a kernel stack.
4267 * **BPF_F_USER_BUILD_ID**
4268 * Collect buildid+offset instead of ips for user stack,
4269 * only valid if **BPF_F_USER_STACK** is also specified.
4271 * **bpf_get_task_stack**\ () can collect up to
4272 * **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
4273 * to sufficient large buffer size. Note that
4274 * this limit can be controlled with the **sysctl** program, and
4275 * that it should be manually increased in order to profile long
4276 * user stacks (such as stacks for Java programs). To do so, use:
4280 * # sysctl kernel.perf_event_max_stack=<new value>
4282 * A non-negative value equal to or less than *size* on success,
4283 * or a negative error in case of failure.
4285 * long bpf_load_hdr_opt(struct bpf_sock_ops *skops, void *searchby_res, u32 len, u64 flags)
4287 * Load header option. Support reading a particular TCP header
4288 * option for bpf program (**BPF_PROG_TYPE_SOCK_OPS**).
4290 * If *flags* is 0, it will search the option from the
4291 * *skops*\ **->skb_data**. The comment in **struct bpf_sock_ops**
4292 * has details on what skb_data contains under different
4293 * *skops*\ **->op**.
4295 * The first byte of the *searchby_res* specifies the
4296 * kind that it wants to search.
4298 * If the searching kind is an experimental kind
4299 * (i.e. 253 or 254 according to RFC6994). It also
4300 * needs to specify the "magic" which is either
4301 * 2 bytes or 4 bytes. It then also needs to
4302 * specify the size of the magic by using
4303 * the 2nd byte which is "kind-length" of a TCP
4304 * header option and the "kind-length" also
4305 * includes the first 2 bytes "kind" and "kind-length"
4306 * itself as a normal TCP header option also does.
4308 * For example, to search experimental kind 254 with
4309 * 2 byte magic 0xeB9F, the searchby_res should be
4310 * [ 254, 4, 0xeB, 0x9F, 0, 0, .... 0 ].
4312 * To search for the standard window scale option (3),
4313 * the *searchby_res* should be [ 3, 0, 0, .... 0 ].
4314 * Note, kind-length must be 0 for regular option.
4316 * Searching for No-Op (0) and End-of-Option-List (1) are
4319 * *len* must be at least 2 bytes which is the minimal size
4320 * of a header option.
4324 * * **BPF_LOAD_HDR_OPT_TCP_SYN** to search from the
4325 * saved_syn packet or the just-received syn packet.
4328 * > 0 when found, the header option is copied to *searchby_res*.
4329 * The return value is the total length copied. On failure, a
4330 * negative error code is returned:
4332 * **-EINVAL** if a parameter is invalid.
4334 * **-ENOMSG** if the option is not found.
4336 * **-ENOENT** if no syn packet is available when
4337 * **BPF_LOAD_HDR_OPT_TCP_SYN** is used.
4339 * **-ENOSPC** if there is not enough space. Only *len* number of
4342 * **-EFAULT** on failure to parse the header options in the
4345 * **-EPERM** if the helper cannot be used under the current
4346 * *skops*\ **->op**.
4348 * long bpf_store_hdr_opt(struct bpf_sock_ops *skops, const void *from, u32 len, u64 flags)
4350 * Store header option. The data will be copied
4351 * from buffer *from* with length *len* to the TCP header.
4353 * The buffer *from* should have the whole option that
4354 * includes the kind, kind-length, and the actual
4355 * option data. The *len* must be at least kind-length
4356 * long. The kind-length does not have to be 4 byte
4357 * aligned. The kernel will take care of the padding
4358 * and setting the 4 bytes aligned value to th->doff.
4360 * This helper will check for duplicated option
4361 * by searching the same option in the outgoing skb.
4363 * This helper can only be called during
4364 * **BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
4367 * 0 on success, or negative error in case of failure:
4369 * **-EINVAL** If param is invalid.
4371 * **-ENOSPC** if there is not enough space in the header.
4372 * Nothing has been written
4374 * **-EEXIST** if the option already exists.
4376 * **-EFAULT** on failrue to parse the existing header options.
4378 * **-EPERM** if the helper cannot be used under the current
4379 * *skops*\ **->op**.
4381 * long bpf_reserve_hdr_opt(struct bpf_sock_ops *skops, u32 len, u64 flags)
4383 * Reserve *len* bytes for the bpf header option. The
4384 * space will be used by **bpf_store_hdr_opt**\ () later in
4385 * **BPF_SOCK_OPS_WRITE_HDR_OPT_CB**.
4387 * If **bpf_reserve_hdr_opt**\ () is called multiple times,
4388 * the total number of bytes will be reserved.
4390 * This helper can only be called during
4391 * **BPF_SOCK_OPS_HDR_OPT_LEN_CB**.
4394 * 0 on success, or negative error in case of failure:
4396 * **-EINVAL** if a parameter is invalid.
4398 * **-ENOSPC** if there is not enough space in the header.
4400 * **-EPERM** if the helper cannot be used under the current
4401 * *skops*\ **->op**.
4403 * void *bpf_inode_storage_get(struct bpf_map *map, void *inode, void *value, u64 flags)
4405 * Get a bpf_local_storage from an *inode*.
4407 * Logically, it could be thought of as getting the value from
4408 * a *map* with *inode* as the **key**. From this
4409 * perspective, the usage is not much different from
4410 * **bpf_map_lookup_elem**\ (*map*, **&**\ *inode*) except this
4411 * helper enforces the key must be an inode and the map must also
4412 * be a **BPF_MAP_TYPE_INODE_STORAGE**.
4414 * Underneath, the value is stored locally at *inode* instead of
4415 * the *map*. The *map* is used as the bpf-local-storage
4416 * "type". The bpf-local-storage "type" (i.e. the *map*) is
4417 * searched against all bpf_local_storage residing at *inode*.
4419 * An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
4420 * used such that a new bpf_local_storage will be
4421 * created if one does not exist. *value* can be used
4422 * together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
4423 * the initial value of a bpf_local_storage. If *value* is
4424 * **NULL**, the new bpf_local_storage will be zero initialized.
4426 * A bpf_local_storage pointer is returned on success.
4428 * **NULL** if not found or there was an error in adding
4429 * a new bpf_local_storage.
4431 * int bpf_inode_storage_delete(struct bpf_map *map, void *inode)
4433 * Delete a bpf_local_storage from an *inode*.
4437 * **-ENOENT** if the bpf_local_storage cannot be found.
4439 * long bpf_d_path(struct path *path, char *buf, u32 sz)
4441 * Return full path for given **struct path** object, which
4442 * needs to be the kernel BTF *path* object. The path is
4443 * returned in the provided buffer *buf* of size *sz* and
4444 * is zero terminated.
4447 * On success, the strictly positive length of the string,
4448 * including the trailing NUL character. On error, a negative
4451 * long bpf_copy_from_user(void *dst, u32 size, const void *user_ptr)
4453 * Read *size* bytes from user space address *user_ptr* and store
4454 * the data in *dst*. This is a wrapper of **copy_from_user**\ ().
4456 * 0 on success, or a negative error in case of failure.
4458 * long bpf_snprintf_btf(char *str, u32 str_size, struct btf_ptr *ptr, u32 btf_ptr_size, u64 flags)
4460 * Use BTF to store a string representation of *ptr*->ptr in *str*,
4461 * using *ptr*->type_id. This value should specify the type
4462 * that *ptr*->ptr points to. LLVM __builtin_btf_type_id(type, 1)
4463 * can be used to look up vmlinux BTF type ids. Traversing the
4464 * data structure using BTF, the type information and values are
4465 * stored in the first *str_size* - 1 bytes of *str*. Safe copy of
4466 * the pointer data is carried out to avoid kernel crashes during
4467 * operation. Smaller types can use string space on the stack;
4468 * larger programs can use map data to store the string
4471 * The string can be subsequently shared with userspace via
4472 * bpf_perf_event_output() or ring buffer interfaces.
4473 * bpf_trace_printk() is to be avoided as it places too small
4474 * a limit on string size to be useful.
4476 * *flags* is a combination of
4479 * no formatting around type information
4481 * no struct/union member names/types
4483 * show raw (unobfuscated) pointer values;
4484 * equivalent to printk specifier %px.
4486 * show zero-valued struct/union members; they
4487 * are not displayed by default
4490 * The number of bytes that were written (or would have been
4491 * written if output had to be truncated due to string size),
4492 * or a negative error in cases of failure.
4494 * long bpf_seq_printf_btf(struct seq_file *m, struct btf_ptr *ptr, u32 ptr_size, u64 flags)
4496 * Use BTF to write to seq_write a string representation of
4497 * *ptr*->ptr, using *ptr*->type_id as per bpf_snprintf_btf().
4498 * *flags* are identical to those used for bpf_snprintf_btf.
4500 * 0 on success or a negative error in case of failure.
4502 * u64 bpf_skb_cgroup_classid(struct sk_buff *skb)
4504 * See **bpf_get_cgroup_classid**\ () for the main description.
4505 * This helper differs from **bpf_get_cgroup_classid**\ () in that
4506 * the cgroup v1 net_cls class is retrieved only from the *skb*'s
4507 * associated socket instead of the current process.
4509 * The id is returned or 0 in case the id could not be retrieved.
4511 * long bpf_redirect_neigh(u32 ifindex, struct bpf_redir_neigh *params, int plen, u64 flags)
4513 * Redirect the packet to another net device of index *ifindex*
4514 * and fill in L2 addresses from neighboring subsystem. This helper
4515 * is somewhat similar to **bpf_redirect**\ (), except that it
4516 * populates L2 addresses as well, meaning, internally, the helper
4517 * relies on the neighbor lookup for the L2 address of the nexthop.
4519 * The helper will perform a FIB lookup based on the skb's
4520 * networking header to get the address of the next hop, unless
4521 * this is supplied by the caller in the *params* argument. The
4522 * *plen* argument indicates the len of *params* and should be set
4523 * to 0 if *params* is NULL.
4525 * The *flags* argument is reserved and must be 0. The helper is
4526 * currently only supported for tc BPF program types, and enabled
4527 * for IPv4 and IPv6 protocols.
4529 * The helper returns **TC_ACT_REDIRECT** on success or
4530 * **TC_ACT_SHOT** on error.
4532 * void *bpf_per_cpu_ptr(const void *percpu_ptr, u32 cpu)
4534 * Take a pointer to a percpu ksym, *percpu_ptr*, and return a
4535 * pointer to the percpu kernel variable on *cpu*. A ksym is an
4536 * extern variable decorated with '__ksym'. For ksym, there is a
4537 * global var (either static or global) defined of the same name
4538 * in the kernel. The ksym is percpu if the global var is percpu.
4539 * The returned pointer points to the global percpu var on *cpu*.
4541 * bpf_per_cpu_ptr() has the same semantic as per_cpu_ptr() in the
4542 * kernel, except that bpf_per_cpu_ptr() may return NULL. This
4543 * happens if *cpu* is larger than nr_cpu_ids. The caller of
4544 * bpf_per_cpu_ptr() must check the returned value.
4546 * A pointer pointing to the kernel percpu variable on *cpu*, or
4547 * NULL, if *cpu* is invalid.
4549 * void *bpf_this_cpu_ptr(const void *percpu_ptr)
4551 * Take a pointer to a percpu ksym, *percpu_ptr*, and return a
4552 * pointer to the percpu kernel variable on this cpu. See the
4553 * description of 'ksym' in **bpf_per_cpu_ptr**\ ().
4555 * bpf_this_cpu_ptr() has the same semantic as this_cpu_ptr() in
4556 * the kernel. Different from **bpf_per_cpu_ptr**\ (), it would
4557 * never return NULL.
4559 * A pointer pointing to the kernel percpu variable on this cpu.
4561 * long bpf_redirect_peer(u32 ifindex, u64 flags)
4563 * Redirect the packet to another net device of index *ifindex*.
4564 * This helper is somewhat similar to **bpf_redirect**\ (), except
4565 * that the redirection happens to the *ifindex*' peer device and
4566 * the netns switch takes place from ingress to ingress without
4567 * going through the CPU's backlog queue.
4569 * The *flags* argument is reserved and must be 0. The helper is
4570 * currently only supported for tc BPF program types at the ingress
4571 * hook and for veth device types. The peer device must reside in a
4572 * different network namespace.
4574 * The helper returns **TC_ACT_REDIRECT** on success or
4575 * **TC_ACT_SHOT** on error.
4577 * void *bpf_task_storage_get(struct bpf_map *map, struct task_struct *task, void *value, u64 flags)
4579 * Get a bpf_local_storage from the *task*.
4581 * Logically, it could be thought of as getting the value from
4582 * a *map* with *task* as the **key**. From this
4583 * perspective, the usage is not much different from
4584 * **bpf_map_lookup_elem**\ (*map*, **&**\ *task*) except this
4585 * helper enforces the key must be an task_struct and the map must also
4586 * be a **BPF_MAP_TYPE_TASK_STORAGE**.
4588 * Underneath, the value is stored locally at *task* instead of
4589 * the *map*. The *map* is used as the bpf-local-storage
4590 * "type". The bpf-local-storage "type" (i.e. the *map*) is
4591 * searched against all bpf_local_storage residing at *task*.
4593 * An optional *flags* (**BPF_LOCAL_STORAGE_GET_F_CREATE**) can be
4594 * used such that a new bpf_local_storage will be
4595 * created if one does not exist. *value* can be used
4596 * together with **BPF_LOCAL_STORAGE_GET_F_CREATE** to specify
4597 * the initial value of a bpf_local_storage. If *value* is
4598 * **NULL**, the new bpf_local_storage will be zero initialized.
4600 * A bpf_local_storage pointer is returned on success.
4602 * **NULL** if not found or there was an error in adding
4603 * a new bpf_local_storage.
4605 * long bpf_task_storage_delete(struct bpf_map *map, struct task_struct *task)
4607 * Delete a bpf_local_storage from a *task*.
4611 * **-ENOENT** if the bpf_local_storage cannot be found.
4613 * struct task_struct *bpf_get_current_task_btf(void)
4615 * Return a BTF pointer to the "current" task.
4616 * This pointer can also be used in helpers that accept an
4617 * *ARG_PTR_TO_BTF_ID* of type *task_struct*.
4619 * Pointer to the current task.
4621 * long bpf_bprm_opts_set(struct linux_binprm *bprm, u64 flags)
4623 * Set or clear certain options on *bprm*:
4625 * **BPF_F_BPRM_SECUREEXEC** Set the secureexec bit
4626 * which sets the **AT_SECURE** auxv for glibc. The bit
4627 * is cleared if the flag is not specified.
4629 * **-EINVAL** if invalid *flags* are passed, zero otherwise.
4631 * u64 bpf_ktime_get_coarse_ns(void)
4633 * Return a coarse-grained version of the time elapsed since
4634 * system boot, in nanoseconds. Does not include time the system
4637 * See: **clock_gettime**\ (**CLOCK_MONOTONIC_COARSE**)
4641 * long bpf_ima_inode_hash(struct inode *inode, void *dst, u32 size)
4643 * Returns the stored IMA hash of the *inode* (if it's avaialable).
4644 * If the hash is larger than *size*, then only *size*
4645 * bytes will be copied to *dst*
4647 * The **hash_algo** is returned on success,
4648 * **-EOPNOTSUP** if IMA is disabled or **-EINVAL** if
4649 * invalid arguments are passed.
4651 * struct socket *bpf_sock_from_file(struct file *file)
4653 * If the given file represents a socket, returns the associated
4656 * A pointer to a struct socket on success or NULL if the file is
4659 * long bpf_check_mtu(void *ctx, u32 ifindex, u32 *mtu_len, s32 len_diff, u64 flags)
4661 * Check packet size against exceeding MTU of net device (based
4662 * on *ifindex*). This helper will likely be used in combination
4663 * with helpers that adjust/change the packet size.
4665 * The argument *len_diff* can be used for querying with a planned
4666 * size change. This allows to check MTU prior to changing packet
4667 * ctx. Providing an *len_diff* adjustment that is larger than the
4668 * actual packet size (resulting in negative packet size) will in
4669 * principle not exceed the MTU, why it is not considered a
4670 * failure. Other BPF-helpers are needed for performing the
4671 * planned size change, why the responsability for catch a negative
4672 * packet size belong in those helpers.
4674 * Specifying *ifindex* zero means the MTU check is performed
4675 * against the current net device. This is practical if this isn't
4676 * used prior to redirect.
4678 * On input *mtu_len* must be a valid pointer, else verifier will
4679 * reject BPF program. If the value *mtu_len* is initialized to
4680 * zero then the ctx packet size is use. When value *mtu_len* is
4681 * provided as input this specify the L3 length that the MTU check
4682 * is done against. Remember XDP and TC length operate at L2, but
4683 * this value is L3 as this correlate to MTU and IP-header tot_len
4684 * values which are L3 (similar behavior as bpf_fib_lookup).
4686 * The Linux kernel route table can configure MTUs on a more
4687 * specific per route level, which is not provided by this helper.
4688 * For route level MTU checks use the **bpf_fib_lookup**\ ()
4691 * *ctx* is either **struct xdp_md** for XDP programs or
4692 * **struct sk_buff** for tc cls_act programs.
4694 * The *flags* argument can be a combination of one or more of the
4697 * **BPF_MTU_CHK_SEGS**
4698 * This flag will only works for *ctx* **struct sk_buff**.
4699 * If packet context contains extra packet segment buffers
4700 * (often knows as GSO skb), then MTU check is harder to
4701 * check at this point, because in transmit path it is
4702 * possible for the skb packet to get re-segmented
4703 * (depending on net device features). This could still be
4704 * a MTU violation, so this flag enables performing MTU
4705 * check against segments, with a different violation
4706 * return code to tell it apart. Check cannot use len_diff.
4708 * On return *mtu_len* pointer contains the MTU value of the net
4709 * device. Remember the net device configured MTU is the L3 size,
4710 * which is returned here and XDP and TC length operate at L2.
4711 * Helper take this into account for you, but remember when using
4712 * MTU value in your BPF-code.
4715 * * 0 on success, and populate MTU value in *mtu_len* pointer.
4717 * * < 0 if any input argument is invalid (*mtu_len* not updated)
4719 * MTU violations return positive values, but also populate MTU
4720 * value in *mtu_len* pointer, as this can be needed for
4721 * implementing PMTU handing:
4723 * * **BPF_MTU_CHK_RET_FRAG_NEEDED**
4724 * * **BPF_MTU_CHK_RET_SEGS_TOOBIG**
4726 * long bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn, void *callback_ctx, u64 flags)
4728 * For each element in **map**, call **callback_fn** function with
4729 * **map**, **callback_ctx** and other map-specific parameters.
4730 * The **callback_fn** should be a static function and
4731 * the **callback_ctx** should be a pointer to the stack.
4732 * The **flags** is used to control certain aspects of the helper.
4733 * Currently, the **flags** must be 0.
4735 * The following are a list of supported map types and their
4736 * respective expected callback signatures:
4738 * BPF_MAP_TYPE_HASH, BPF_MAP_TYPE_PERCPU_HASH,
4739 * BPF_MAP_TYPE_LRU_HASH, BPF_MAP_TYPE_LRU_PERCPU_HASH,
4740 * BPF_MAP_TYPE_ARRAY, BPF_MAP_TYPE_PERCPU_ARRAY
4742 * long (\*callback_fn)(struct bpf_map \*map, const void \*key, void \*value, void \*ctx);
4744 * For per_cpu maps, the map_value is the value on the cpu where the
4745 * bpf_prog is running.
4747 * If **callback_fn** return 0, the helper will continue to the next
4748 * element. If return value is 1, the helper will skip the rest of
4749 * elements and return. Other return values are not used now.
4752 * The number of traversed map elements for success, **-EINVAL** for
4753 * invalid **flags**.
4755 * long bpf_snprintf(char *str, u32 str_size, const char *fmt, u64 *data, u32 data_len)
4757 * Outputs a string into the **str** buffer of size **str_size**
4758 * based on a format string stored in a read-only map pointed by
4761 * Each format specifier in **fmt** corresponds to one u64 element
4762 * in the **data** array. For strings and pointers where pointees
4763 * are accessed, only the pointer values are stored in the *data*
4764 * array. The *data_len* is the size of *data* in bytes - must be
4767 * Formats **%s** and **%p{i,I}{4,6}** require to read kernel
4768 * memory. Reading kernel memory may fail due to either invalid
4769 * address or valid address but requiring a major memory fault. If
4770 * reading kernel memory fails, the string for **%s** will be an
4771 * empty string, and the ip address for **%p{i,I}{4,6}** will be 0.
4772 * Not returning error to bpf program is consistent with what
4773 * **bpf_trace_printk**\ () does for now.
4776 * The strictly positive length of the formatted string, including
4777 * the trailing zero character. If the return value is greater than
4778 * **str_size**, **str** contains a truncated string, guaranteed to
4779 * be zero-terminated except when **str_size** is 0.
4781 * Or **-EBUSY** if the per-CPU memory copy buffer is busy.
4783 * long bpf_sys_bpf(u32 cmd, void *attr, u32 attr_size)
4785 * Execute bpf syscall with given arguments.
4789 * long bpf_btf_find_by_name_kind(char *name, int name_sz, u32 kind, int flags)
4791 * Find BTF type with given name and kind in vmlinux BTF or in module's BTFs.
4793 * Returns btf_id and btf_obj_fd in lower and upper 32 bits.
4795 * long bpf_sys_close(u32 fd)
4797 * Execute close syscall for given FD.
4801 * long bpf_timer_init(struct bpf_timer *timer, struct bpf_map *map, u64 flags)
4803 * Initialize the timer.
4804 * First 4 bits of *flags* specify clockid.
4805 * Only CLOCK_MONOTONIC, CLOCK_REALTIME, CLOCK_BOOTTIME are allowed.
4806 * All other bits of *flags* are reserved.
4807 * The verifier will reject the program if *timer* is not from
4811 * **-EBUSY** if *timer* is already initialized.
4812 * **-EINVAL** if invalid *flags* are passed.
4813 * **-EPERM** if *timer* is in a map that doesn't have any user references.
4814 * The user space should either hold a file descriptor to a map with timers
4815 * or pin such map in bpffs. When map is unpinned or file descriptor is
4816 * closed all timers in the map will be cancelled and freed.
4818 * long bpf_timer_set_callback(struct bpf_timer *timer, void *callback_fn)
4820 * Configure the timer to call *callback_fn* static function.
4823 * **-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
4824 * **-EPERM** if *timer* is in a map that doesn't have any user references.
4825 * The user space should either hold a file descriptor to a map with timers
4826 * or pin such map in bpffs. When map is unpinned or file descriptor is
4827 * closed all timers in the map will be cancelled and freed.
4829 * long bpf_timer_start(struct bpf_timer *timer, u64 nsecs, u64 flags)
4831 * Set timer expiration N nanoseconds from the current time. The
4832 * configured callback will be invoked in soft irq context on some cpu
4833 * and will not repeat unless another bpf_timer_start() is made.
4834 * In such case the next invocation can migrate to a different cpu.
4835 * Since struct bpf_timer is a field inside map element the map
4836 * owns the timer. The bpf_timer_set_callback() will increment refcnt
4837 * of BPF program to make sure that callback_fn code stays valid.
4838 * When user space reference to a map reaches zero all timers
4839 * in a map are cancelled and corresponding program's refcnts are
4840 * decremented. This is done to make sure that Ctrl-C of a user
4841 * process doesn't leave any timers running. If map is pinned in
4842 * bpffs the callback_fn can re-arm itself indefinitely.
4843 * bpf_map_update/delete_elem() helpers and user space sys_bpf commands
4844 * cancel and free the timer in the given map element.
4845 * The map can contain timers that invoke callback_fn-s from different
4846 * programs. The same callback_fn can serve different timers from
4847 * different maps if key/value layout matches across maps.
4848 * Every bpf_timer_set_callback() can have different callback_fn.
4852 * **-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier
4853 * or invalid *flags* are passed.
4855 * long bpf_timer_cancel(struct bpf_timer *timer)
4857 * Cancel the timer and wait for callback_fn to finish if it was running.
4859 * 0 if the timer was not active.
4860 * 1 if the timer was active.
4861 * **-EINVAL** if *timer* was not initialized with bpf_timer_init() earlier.
4862 * **-EDEADLK** if callback_fn tried to call bpf_timer_cancel() on its
4863 * own timer which would have led to a deadlock otherwise.
4865 * u64 bpf_get_func_ip(void *ctx)
4867 * Get address of the traced function (for tracing and kprobe programs).
4869 * Address of the traced function.
4871 * u64 bpf_get_attach_cookie(void *ctx)
4873 * Get bpf_cookie value provided (optionally) during the program
4874 * attachment. It might be different for each individual
4875 * attachment, even if BPF program itself is the same.
4876 * Expects BPF program context *ctx* as a first argument.
4878 * Supported for the following program types:
4883 * Value specified by user at BPF link creation/attachment time
4884 * or 0, if it was not specified.
4886 * long bpf_task_pt_regs(struct task_struct *task)
4888 * Get the struct pt_regs associated with **task**.
4890 * A pointer to struct pt_regs.
4892 * long bpf_get_branch_snapshot(void *entries, u32 size, u64 flags)
4894 * Get branch trace from hardware engines like Intel LBR. The
4895 * hardware engine is stopped shortly after the helper is
4896 * called. Therefore, the user need to filter branch entries
4897 * based on the actual use case. To capture branch trace
4898 * before the trigger point of the BPF program, the helper
4899 * should be called at the beginning of the BPF program.
4901 * The data is stored as struct perf_branch_entry into output
4902 * buffer *entries*. *size* is the size of *entries* in bytes.
4903 * *flags* is reserved for now and must be zero.
4906 * On success, number of bytes written to *buf*. On error, a
4909 * **-EINVAL** if *flags* is not zero.
4911 * **-ENOENT** if architecture does not support branch records.
4913 * long bpf_trace_vprintk(const char *fmt, u32 fmt_size, const void *data, u32 data_len)
4915 * Behaves like **bpf_trace_printk**\ () helper, but takes an array of u64
4916 * to format and can handle more format args as a result.
4918 * Arguments are to be used as in **bpf_seq_printf**\ () helper.
4920 * The number of bytes written to the buffer, or a negative error
4921 * in case of failure.
4923 * struct unix_sock *bpf_skc_to_unix_sock(void *sk)
4925 * Dynamically cast a *sk* pointer to a *unix_sock* pointer.
4927 * *sk* if casting is valid, or **NULL** otherwise.
4929 * long bpf_kallsyms_lookup_name(const char *name, int name_sz, int flags, u64 *res)
4931 * Get the address of a kernel symbol, returned in *res*. *res* is
4932 * set to 0 if the symbol is not found.
4934 * On success, zero. On error, a negative value.
4936 * **-EINVAL** if *flags* is not zero.
4938 * **-EINVAL** if string *name* is not the same size as *name_sz*.
4940 * **-ENOENT** if symbol is not found.
4942 * **-EPERM** if caller does not have permission to obtain kernel address.
4944 * long bpf_find_vma(struct task_struct *task, u64 addr, void *callback_fn, void *callback_ctx, u64 flags)
4946 * Find vma of *task* that contains *addr*, call *callback_fn*
4947 * function with *task*, *vma*, and *callback_ctx*.
4948 * The *callback_fn* should be a static function and
4949 * the *callback_ctx* should be a pointer to the stack.
4950 * The *flags* is used to control certain aspects of the helper.
4951 * Currently, the *flags* must be 0.
4953 * The expected callback signature is
4955 * long (\*callback_fn)(struct task_struct \*task, struct vm_area_struct \*vma, void \*callback_ctx);
4959 * **-ENOENT** if *task->mm* is NULL, or no vma contains *addr*.
4960 * **-EBUSY** if failed to try lock mmap_lock.
4961 * **-EINVAL** for invalid **flags**.
4963 * long bpf_loop(u32 nr_loops, void *callback_fn, void *callback_ctx, u64 flags)
4965 * For **nr_loops**, call **callback_fn** function
4966 * with **callback_ctx** as the context parameter.
4967 * The **callback_fn** should be a static function and
4968 * the **callback_ctx** should be a pointer to the stack.
4969 * The **flags** is used to control certain aspects of the helper.
4970 * Currently, the **flags** must be 0. Currently, nr_loops is
4971 * limited to 1 << 23 (~8 million) loops.
4973 * long (\*callback_fn)(u32 index, void \*ctx);
4975 * where **index** is the current index in the loop. The index
4978 * If **callback_fn** returns 0, the helper will continue to the next
4979 * loop. If return value is 1, the helper will skip the rest of
4980 * the loops and return. Other return values are not used now,
4981 * and will be rejected by the verifier.
4984 * The number of loops performed, **-EINVAL** for invalid **flags**,
4985 * **-E2BIG** if **nr_loops** exceeds the maximum number of loops.
4987 * long bpf_strncmp(const char *s1, u32 s1_sz, const char *s2)
4989 * Do strncmp() between **s1** and **s2**. **s1** doesn't need
4990 * to be null-terminated and **s1_sz** is the maximum storage
4991 * size of **s1**. **s2** must be a read-only string.
4993 * An integer less than, equal to, or greater than zero
4994 * if the first **s1_sz** bytes of **s1** is found to be
4995 * less than, to match, or be greater than **s2**.
4997 * long bpf_get_func_arg(void *ctx, u32 n, u64 *value)
4999 * Get **n**-th argument (zero based) of the traced function (for tracing programs)
5000 * returned in **value**.
5004 * **-EINVAL** if n >= arguments count of traced function.
5006 * long bpf_get_func_ret(void *ctx, u64 *value)
5008 * Get return value of the traced function (for tracing programs)
5013 * **-EOPNOTSUPP** for tracing programs other than BPF_TRACE_FEXIT or BPF_MODIFY_RETURN.
5015 * long bpf_get_func_arg_cnt(void *ctx)
5017 * Get number of arguments of the traced function (for tracing programs).
5020 * The number of arguments of the traced function.
5022 #define __BPF_FUNC_MAPPER(FN) \
5024 FN(map_lookup_elem), \
5025 FN(map_update_elem), \
5026 FN(map_delete_elem), \
5030 FN(get_prandom_u32), \
5031 FN(get_smp_processor_id), \
5032 FN(skb_store_bytes), \
5033 FN(l3_csum_replace), \
5034 FN(l4_csum_replace), \
5036 FN(clone_redirect), \
5037 FN(get_current_pid_tgid), \
5038 FN(get_current_uid_gid), \
5039 FN(get_current_comm), \
5040 FN(get_cgroup_classid), \
5041 FN(skb_vlan_push), \
5043 FN(skb_get_tunnel_key), \
5044 FN(skb_set_tunnel_key), \
5045 FN(perf_event_read), \
5047 FN(get_route_realm), \
5048 FN(perf_event_output), \
5049 FN(skb_load_bytes), \
5052 FN(skb_get_tunnel_opt), \
5053 FN(skb_set_tunnel_opt), \
5054 FN(skb_change_proto), \
5055 FN(skb_change_type), \
5056 FN(skb_under_cgroup), \
5057 FN(get_hash_recalc), \
5058 FN(get_current_task), \
5059 FN(probe_write_user), \
5060 FN(current_task_under_cgroup), \
5061 FN(skb_change_tail), \
5062 FN(skb_pull_data), \
5064 FN(set_hash_invalid), \
5065 FN(get_numa_node_id), \
5066 FN(skb_change_head), \
5067 FN(xdp_adjust_head), \
5068 FN(probe_read_str), \
5069 FN(get_socket_cookie), \
5070 FN(get_socket_uid), \
5073 FN(skb_adjust_room), \
5075 FN(sk_redirect_map), \
5076 FN(sock_map_update), \
5077 FN(xdp_adjust_meta), \
5078 FN(perf_event_read_value), \
5079 FN(perf_prog_read_value), \
5081 FN(override_return), \
5082 FN(sock_ops_cb_flags_set), \
5083 FN(msg_redirect_map), \
5084 FN(msg_apply_bytes), \
5085 FN(msg_cork_bytes), \
5086 FN(msg_pull_data), \
5088 FN(xdp_adjust_tail), \
5089 FN(skb_get_xfrm_state), \
5091 FN(skb_load_bytes_relative), \
5093 FN(sock_hash_update), \
5094 FN(msg_redirect_hash), \
5095 FN(sk_redirect_hash), \
5096 FN(lwt_push_encap), \
5097 FN(lwt_seg6_store_bytes), \
5098 FN(lwt_seg6_adjust_srh), \
5099 FN(lwt_seg6_action), \
5102 FN(skb_cgroup_id), \
5103 FN(get_current_cgroup_id), \
5104 FN(get_local_storage), \
5105 FN(sk_select_reuseport), \
5106 FN(skb_ancestor_cgroup_id), \
5107 FN(sk_lookup_tcp), \
5108 FN(sk_lookup_udp), \
5110 FN(map_push_elem), \
5112 FN(map_peek_elem), \
5113 FN(msg_push_data), \
5115 FN(rc_pointer_rel), \
5120 FN(skb_ecn_set_ce), \
5121 FN(get_listener_sock), \
5122 FN(skc_lookup_tcp), \
5123 FN(tcp_check_syncookie), \
5124 FN(sysctl_get_name), \
5125 FN(sysctl_get_current_value), \
5126 FN(sysctl_get_new_value), \
5127 FN(sysctl_set_new_value), \
5130 FN(sk_storage_get), \
5131 FN(sk_storage_delete), \
5133 FN(tcp_gen_syncookie), \
5135 FN(probe_read_user), \
5136 FN(probe_read_kernel), \
5137 FN(probe_read_user_str), \
5138 FN(probe_read_kernel_str), \
5140 FN(send_signal_thread), \
5142 FN(read_branch_records), \
5143 FN(get_ns_current_pid_tgid), \
5145 FN(get_netns_cookie), \
5146 FN(get_current_ancestor_cgroup_id), \
5148 FN(ktime_get_boot_ns), \
5152 FN(sk_ancestor_cgroup_id), \
5153 FN(ringbuf_output), \
5154 FN(ringbuf_reserve), \
5155 FN(ringbuf_submit), \
5156 FN(ringbuf_discard), \
5157 FN(ringbuf_query), \
5159 FN(skc_to_tcp6_sock), \
5160 FN(skc_to_tcp_sock), \
5161 FN(skc_to_tcp_timewait_sock), \
5162 FN(skc_to_tcp_request_sock), \
5163 FN(skc_to_udp6_sock), \
5164 FN(get_task_stack), \
5166 FN(store_hdr_opt), \
5167 FN(reserve_hdr_opt), \
5168 FN(inode_storage_get), \
5169 FN(inode_storage_delete), \
5171 FN(copy_from_user), \
5173 FN(seq_printf_btf), \
5174 FN(skb_cgroup_classid), \
5175 FN(redirect_neigh), \
5178 FN(redirect_peer), \
5179 FN(task_storage_get), \
5180 FN(task_storage_delete), \
5181 FN(get_current_task_btf), \
5182 FN(bprm_opts_set), \
5183 FN(ktime_get_coarse_ns), \
5184 FN(ima_inode_hash), \
5185 FN(sock_from_file), \
5187 FN(for_each_map_elem), \
5190 FN(btf_find_by_name_kind), \
5193 FN(timer_set_callback), \
5197 FN(get_attach_cookie), \
5199 FN(get_branch_snapshot), \
5200 FN(trace_vprintk), \
5201 FN(skc_to_unix_sock), \
5202 FN(kallsyms_lookup_name), \
5208 FN(get_func_arg_cnt), \
5211 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
5212 * function eBPF program intends to call
5214 #define __BPF_ENUM_FN(x) BPF_FUNC_ ## x
5216 __BPF_FUNC_MAPPER(__BPF_ENUM_FN)
5219 #undef __BPF_ENUM_FN
5221 /* All flags used by eBPF helper functions, placed here. */
5223 /* BPF_FUNC_skb_store_bytes flags. */
5225 BPF_F_RECOMPUTE_CSUM = (1ULL << 0),
5226 BPF_F_INVALIDATE_HASH = (1ULL << 1),
5229 /* BPF_FUNC_l3_csum_replace and BPF_FUNC_l4_csum_replace flags.
5230 * First 4 bits are for passing the header field size.
5233 BPF_F_HDR_FIELD_MASK = 0xfULL,
5236 /* BPF_FUNC_l4_csum_replace flags. */
5238 BPF_F_PSEUDO_HDR = (1ULL << 4),
5239 BPF_F_MARK_MANGLED_0 = (1ULL << 5),
5240 BPF_F_MARK_ENFORCE = (1ULL << 6),
5243 /* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */
5245 BPF_F_INGRESS = (1ULL << 0),
5248 /* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */
5250 BPF_F_TUNINFO_IPV6 = (1ULL << 0),
5253 /* flags for both BPF_FUNC_get_stackid and BPF_FUNC_get_stack. */
5255 BPF_F_SKIP_FIELD_MASK = 0xffULL,
5256 BPF_F_USER_STACK = (1ULL << 8),
5257 /* flags used by BPF_FUNC_get_stackid only. */
5258 BPF_F_FAST_STACK_CMP = (1ULL << 9),
5259 BPF_F_REUSE_STACKID = (1ULL << 10),
5260 /* flags used by BPF_FUNC_get_stack only. */
5261 BPF_F_USER_BUILD_ID = (1ULL << 11),
5264 /* BPF_FUNC_skb_set_tunnel_key flags. */
5266 BPF_F_ZERO_CSUM_TX = (1ULL << 1),
5267 BPF_F_DONT_FRAGMENT = (1ULL << 2),
5268 BPF_F_SEQ_NUMBER = (1ULL << 3),
5271 /* BPF_FUNC_perf_event_output, BPF_FUNC_perf_event_read and
5272 * BPF_FUNC_perf_event_read_value flags.
5275 BPF_F_INDEX_MASK = 0xffffffffULL,
5276 BPF_F_CURRENT_CPU = BPF_F_INDEX_MASK,
5277 /* BPF_FUNC_perf_event_output for sk_buff input context. */
5278 BPF_F_CTXLEN_MASK = (0xfffffULL << 32),
5281 /* Current network namespace */
5283 BPF_F_CURRENT_NETNS = (-1L),
5286 /* BPF_FUNC_csum_level level values. */
5288 BPF_CSUM_LEVEL_QUERY,
5291 BPF_CSUM_LEVEL_RESET,
5294 /* BPF_FUNC_skb_adjust_room flags. */
5296 BPF_F_ADJ_ROOM_FIXED_GSO = (1ULL << 0),
5297 BPF_F_ADJ_ROOM_ENCAP_L3_IPV4 = (1ULL << 1),
5298 BPF_F_ADJ_ROOM_ENCAP_L3_IPV6 = (1ULL << 2),
5299 BPF_F_ADJ_ROOM_ENCAP_L4_GRE = (1ULL << 3),
5300 BPF_F_ADJ_ROOM_ENCAP_L4_UDP = (1ULL << 4),
5301 BPF_F_ADJ_ROOM_NO_CSUM_RESET = (1ULL << 5),
5302 BPF_F_ADJ_ROOM_ENCAP_L2_ETH = (1ULL << 6),
5306 BPF_ADJ_ROOM_ENCAP_L2_MASK = 0xff,
5307 BPF_ADJ_ROOM_ENCAP_L2_SHIFT = 56,
5310 #define BPF_F_ADJ_ROOM_ENCAP_L2(len) (((__u64)len & \
5311 BPF_ADJ_ROOM_ENCAP_L2_MASK) \
5312 << BPF_ADJ_ROOM_ENCAP_L2_SHIFT)
5314 /* BPF_FUNC_sysctl_get_name flags. */
5316 BPF_F_SYSCTL_BASE_NAME = (1ULL << 0),
5319 /* BPF_FUNC_<kernel_obj>_storage_get flags */
5321 BPF_LOCAL_STORAGE_GET_F_CREATE = (1ULL << 0),
5322 /* BPF_SK_STORAGE_GET_F_CREATE is only kept for backward compatibility
5323 * and BPF_LOCAL_STORAGE_GET_F_CREATE must be used instead.
5325 BPF_SK_STORAGE_GET_F_CREATE = BPF_LOCAL_STORAGE_GET_F_CREATE,
5328 /* BPF_FUNC_read_branch_records flags. */
5330 BPF_F_GET_BRANCH_RECORDS_SIZE = (1ULL << 0),
5333 /* BPF_FUNC_bpf_ringbuf_commit, BPF_FUNC_bpf_ringbuf_discard, and
5334 * BPF_FUNC_bpf_ringbuf_output flags.
5337 BPF_RB_NO_WAKEUP = (1ULL << 0),
5338 BPF_RB_FORCE_WAKEUP = (1ULL << 1),
5341 /* BPF_FUNC_bpf_ringbuf_query flags */
5343 BPF_RB_AVAIL_DATA = 0,
5344 BPF_RB_RING_SIZE = 1,
5345 BPF_RB_CONS_POS = 2,
5346 BPF_RB_PROD_POS = 3,
5349 /* BPF ring buffer constants */
5351 BPF_RINGBUF_BUSY_BIT = (1U << 31),
5352 BPF_RINGBUF_DISCARD_BIT = (1U << 30),
5353 BPF_RINGBUF_HDR_SZ = 8,
5356 /* BPF_FUNC_sk_assign flags in bpf_sk_lookup context. */
5358 BPF_SK_LOOKUP_F_REPLACE = (1ULL << 0),
5359 BPF_SK_LOOKUP_F_NO_REUSEPORT = (1ULL << 1),
5362 /* Mode for BPF_FUNC_skb_adjust_room helper. */
5363 enum bpf_adj_room_mode {
5368 /* Mode for BPF_FUNC_skb_load_bytes_relative helper. */
5369 enum bpf_hdr_start_off {
5374 /* Encapsulation type for BPF_FUNC_lwt_push_encap helper. */
5375 enum bpf_lwt_encap_mode {
5377 BPF_LWT_ENCAP_SEG6_INLINE,
5381 /* Flags for bpf_bprm_opts_set helper */
5383 BPF_F_BPRM_SECUREEXEC = (1ULL << 0),
5386 /* Flags for bpf_redirect_map helper */
5388 BPF_F_BROADCAST = (1ULL << 3),
5389 BPF_F_EXCLUDE_INGRESS = (1ULL << 4),
5392 #define __bpf_md_ptr(type, name) \
5396 } __attribute__((aligned(8)))
5398 /* user accessible mirror of in-kernel sk_buff.
5399 * new fields can only be added to the end of this structure
5405 __u32 queue_mapping;
5411 __u32 ingress_ifindex;
5421 /* Accessed by BPF_PROG_TYPE_sk_skb types from here to ... */
5423 __u32 remote_ip4; /* Stored in network byte order */
5424 __u32 local_ip4; /* Stored in network byte order */
5425 __u32 remote_ip6[4]; /* Stored in network byte order */
5426 __u32 local_ip6[4]; /* Stored in network byte order */
5427 __u32 remote_port; /* Stored in network byte order */
5428 __u32 local_port; /* stored in host byte order */
5432 __bpf_md_ptr(struct bpf_flow_keys *, flow_keys);
5436 __bpf_md_ptr(struct bpf_sock *, sk);
5438 __u32 :32; /* Padding, future use. */
5442 struct bpf_tunnel_key {
5446 __u32 remote_ipv6[4];
5450 __u16 tunnel_ext; /* Padding, future use. */
5454 /* user accessible mirror of in-kernel xfrm_state.
5455 * new fields can only be added to the end of this structure
5457 struct bpf_xfrm_state {
5459 __u32 spi; /* Stored in network byte order */
5461 __u16 ext; /* Padding, future use. */
5463 __u32 remote_ipv4; /* Stored in network byte order */
5464 __u32 remote_ipv6[4]; /* Stored in network byte order */
5468 /* Generic BPF return codes which all BPF program types may support.
5469 * The values are binary compatible with their TC_ACT_* counter-part to
5470 * provide backwards compatibility with existing SCHED_CLS and SCHED_ACT
5473 * XDP is handled seprately, see XDP_*.
5481 /* >127 are reserved for prog type specific return codes.
5483 * BPF_LWT_REROUTE: used by BPF_PROG_TYPE_LWT_IN and
5484 * BPF_PROG_TYPE_LWT_XMIT to indicate that skb had been
5485 * changed and should be routed based on its new L3 header.
5486 * (This is an L3 redirect, as opposed to L2 redirect
5487 * represented by BPF_REDIRECT above).
5489 BPF_LWT_REROUTE = 128,
5499 /* IP address also allows 1 and 2 bytes access */
5502 __u32 src_port; /* host byte order */
5503 __u32 dst_port; /* network byte order */
5507 __s32 rx_queue_mapping;
5510 struct bpf_tcp_sock {
5511 __u32 snd_cwnd; /* Sending congestion window */
5512 __u32 srtt_us; /* smoothed round trip time << 3 in usecs */
5514 __u32 snd_ssthresh; /* Slow start size threshold */
5515 __u32 rcv_nxt; /* What we want to receive next */
5516 __u32 snd_nxt; /* Next sequence we send */
5517 __u32 snd_una; /* First byte we want an ack for */
5518 __u32 mss_cache; /* Cached effective mss, not including SACKS */
5519 __u32 ecn_flags; /* ECN status bits. */
5520 __u32 rate_delivered; /* saved rate sample: packets delivered */
5521 __u32 rate_interval_us; /* saved rate sample: time elapsed */
5522 __u32 packets_out; /* Packets which are "in flight" */
5523 __u32 retrans_out; /* Retransmitted packets out */
5524 __u32 total_retrans; /* Total retransmits for entire connection */
5525 __u32 segs_in; /* RFC4898 tcpEStatsPerfSegsIn
5526 * total number of segments in.
5528 __u32 data_segs_in; /* RFC4898 tcpEStatsPerfDataSegsIn
5529 * total number of data segments in.
5531 __u32 segs_out; /* RFC4898 tcpEStatsPerfSegsOut
5532 * The total number of segments sent.
5534 __u32 data_segs_out; /* RFC4898 tcpEStatsPerfDataSegsOut
5535 * total number of data segments sent.
5537 __u32 lost_out; /* Lost packets */
5538 __u32 sacked_out; /* SACK'd packets */
5539 __u64 bytes_received; /* RFC4898 tcpEStatsAppHCThruOctetsReceived
5540 * sum(delta(rcv_nxt)), or how many bytes
5543 __u64 bytes_acked; /* RFC4898 tcpEStatsAppHCThruOctetsAcked
5544 * sum(delta(snd_una)), or how many bytes
5547 __u32 dsack_dups; /* RFC4898 tcpEStatsStackDSACKDups
5548 * total number of DSACK blocks received
5550 __u32 delivered; /* Total data packets delivered incl. rexmits */
5551 __u32 delivered_ce; /* Like the above but only ECE marked packets */
5552 __u32 icsk_retransmits; /* Number of unrecovered [RTO] timeouts */
5555 struct bpf_sock_tuple {
5572 struct bpf_xdp_sock {
5576 #define XDP_PACKET_HEADROOM 256
5578 /* User return codes for XDP prog type.
5579 * A valid XDP program must return one of these defined values. All other
5580 * return codes are reserved for future use. Unknown return codes will
5581 * result in packet drops and a warning via bpf_warn_invalid_xdp_action().
5591 /* user accessible metadata for XDP packet hook
5592 * new fields must be added to the end of this structure
5598 /* Below access go through struct xdp_rxq_info */
5599 __u32 ingress_ifindex; /* rxq->dev->ifindex */
5600 __u32 rx_queue_index; /* rxq->queue_index */
5602 __u32 egress_ifindex; /* txq->dev->ifindex */
5605 /* DEVMAP map-value layout
5607 * The struct data-layout of map-value is a configuration interface.
5608 * New members can only be added to the end of this structure.
5610 struct bpf_devmap_val {
5611 __u32 ifindex; /* device index */
5613 int fd; /* prog fd on map write */
5614 __u32 id; /* prog id on map read */
5618 /* CPUMAP map-value layout
5620 * The struct data-layout of map-value is a configuration interface.
5621 * New members can only be added to the end of this structure.
5623 struct bpf_cpumap_val {
5624 __u32 qsize; /* queue size to remote target CPU */
5626 int fd; /* prog fd on map write */
5627 __u32 id; /* prog id on map read */
5636 /* user accessible metadata for SK_MSG packet hook, new fields must
5637 * be added to the end of this structure
5640 __bpf_md_ptr(void *, data);
5641 __bpf_md_ptr(void *, data_end);
5644 __u32 remote_ip4; /* Stored in network byte order */
5645 __u32 local_ip4; /* Stored in network byte order */
5646 __u32 remote_ip6[4]; /* Stored in network byte order */
5647 __u32 local_ip6[4]; /* Stored in network byte order */
5648 __u32 remote_port; /* Stored in network byte order */
5649 __u32 local_port; /* stored in host byte order */
5650 __u32 size; /* Total size of sk_msg */
5652 __bpf_md_ptr(struct bpf_sock *, sk); /* current socket */
5655 struct sk_reuseport_md {
5657 * Start of directly accessible data. It begins from
5658 * the tcp/udp header.
5660 __bpf_md_ptr(void *, data);
5661 /* End of directly accessible data */
5662 __bpf_md_ptr(void *, data_end);
5664 * Total length of packet (starting from the tcp/udp header).
5665 * Note that the directly accessible bytes (data_end - data)
5666 * could be less than this "len". Those bytes could be
5667 * indirectly read by a helper "bpf_skb_load_bytes()".
5671 * Eth protocol in the mac header (network byte order). e.g.
5672 * ETH_P_IP(0x0800) and ETH_P_IPV6(0x86DD)
5675 __u32 ip_protocol; /* IP protocol. e.g. IPPROTO_TCP, IPPROTO_UDP */
5676 __u32 bind_inany; /* Is sock bound to an INANY address? */
5677 __u32 hash; /* A hash of the packet 4 tuples */
5678 /* When reuse->migrating_sk is NULL, it is selecting a sk for the
5679 * new incoming connection request (e.g. selecting a listen sk for
5680 * the received SYN in the TCP case). reuse->sk is one of the sk
5681 * in the reuseport group. The bpf prog can use reuse->sk to learn
5682 * the local listening ip/port without looking into the skb.
5684 * When reuse->migrating_sk is not NULL, reuse->sk is closed and
5685 * reuse->migrating_sk is the socket that needs to be migrated
5686 * to another listening socket. migrating_sk could be a fullsock
5687 * sk that is fully established or a reqsk that is in-the-middle
5688 * of 3-way handshake.
5690 __bpf_md_ptr(struct bpf_sock *, sk);
5691 __bpf_md_ptr(struct bpf_sock *, migrating_sk);
5694 #define BPF_TAG_SIZE 8
5696 struct bpf_prog_info {
5699 __u8 tag[BPF_TAG_SIZE];
5700 __u32 jited_prog_len;
5701 __u32 xlated_prog_len;
5702 __aligned_u64 jited_prog_insns;
5703 __aligned_u64 xlated_prog_insns;
5704 __u64 load_time; /* ns since boottime */
5705 __u32 created_by_uid;
5707 __aligned_u64 map_ids;
5708 char name[BPF_OBJ_NAME_LEN];
5710 __u32 gpl_compatible:1;
5711 __u32 :31; /* alignment pad */
5714 __u32 nr_jited_ksyms;
5715 __u32 nr_jited_func_lens;
5716 __aligned_u64 jited_ksyms;
5717 __aligned_u64 jited_func_lens;
5719 __u32 func_info_rec_size;
5720 __aligned_u64 func_info;
5723 __aligned_u64 line_info;
5724 __aligned_u64 jited_line_info;
5725 __u32 nr_jited_line_info;
5726 __u32 line_info_rec_size;
5727 __u32 jited_line_info_rec_size;
5729 __aligned_u64 prog_tags;
5732 __u64 recursion_misses;
5733 __u32 verified_insns;
5734 } __attribute__((aligned(8)));
5736 struct bpf_map_info {
5743 char name[BPF_OBJ_NAME_LEN];
5745 __u32 btf_vmlinux_value_type_id;
5749 __u32 btf_key_type_id;
5750 __u32 btf_value_type_id;
5751 __u32 :32; /* alignment pad */
5753 } __attribute__((aligned(8)));
5755 struct bpf_btf_info {
5762 } __attribute__((aligned(8)));
5764 struct bpf_link_info {
5770 __aligned_u64 tp_name; /* in/out: tp_name buffer ptr */
5771 __u32 tp_name_len; /* in/out: tp_name buffer len */
5775 __u32 target_obj_id; /* prog_id for PROG_EXT, otherwise btf object id */
5776 __u32 target_btf_id; /* BTF type id inside the object */
5783 __aligned_u64 target_name; /* in/out: target_name buffer ptr */
5784 __u32 target_name_len; /* in/out: target_name buffer len */
5799 } __attribute__((aligned(8)));
5801 /* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
5802 * by user and intended to be used by socket (e.g. to bind to, depends on
5805 struct bpf_sock_addr {
5806 __u32 user_family; /* Allows 4-byte read, but no write. */
5807 __u32 user_ip4; /* Allows 1,2,4-byte read and 4-byte write.
5808 * Stored in network byte order.
5810 __u32 user_ip6[4]; /* Allows 1,2,4,8-byte read and 4,8-byte write.
5811 * Stored in network byte order.
5813 __u32 user_port; /* Allows 1,2,4-byte read and 4-byte write.
5814 * Stored in network byte order
5816 __u32 family; /* Allows 4-byte read, but no write */
5817 __u32 type; /* Allows 4-byte read, but no write */
5818 __u32 protocol; /* Allows 4-byte read, but no write */
5819 __u32 msg_src_ip4; /* Allows 1,2,4-byte read and 4-byte write.
5820 * Stored in network byte order.
5822 __u32 msg_src_ip6[4]; /* Allows 1,2,4,8-byte read and 4,8-byte write.
5823 * Stored in network byte order.
5825 __bpf_md_ptr(struct bpf_sock *, sk);
5828 /* User bpf_sock_ops struct to access socket values and specify request ops
5829 * and their replies.
5830 * Some of this fields are in network (bigendian) byte order and may need
5831 * to be converted before use (bpf_ntohl() defined in samples/bpf/bpf_endian.h).
5832 * New fields can only be added at the end of this structure
5834 struct bpf_sock_ops {
5837 __u32 args[4]; /* Optionally passed to bpf program */
5838 __u32 reply; /* Returned by bpf program */
5839 __u32 replylong[4]; /* Optionally returned by bpf prog */
5842 __u32 remote_ip4; /* Stored in network byte order */
5843 __u32 local_ip4; /* Stored in network byte order */
5844 __u32 remote_ip6[4]; /* Stored in network byte order */
5845 __u32 local_ip6[4]; /* Stored in network byte order */
5846 __u32 remote_port; /* Stored in network byte order */
5847 __u32 local_port; /* stored in host byte order */
5848 __u32 is_fullsock; /* Some TCP fields are only valid if
5849 * there is a full socket. If not, the
5850 * fields read as zero.
5853 __u32 srtt_us; /* Averaged RTT << 3 in usecs */
5854 __u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
5863 __u32 rate_delivered;
5864 __u32 rate_interval_us;
5867 __u32 total_retrans;
5871 __u32 data_segs_out;
5875 __u64 bytes_received;
5877 __bpf_md_ptr(struct bpf_sock *, sk);
5878 /* [skb_data, skb_data_end) covers the whole TCP header.
5880 * BPF_SOCK_OPS_PARSE_HDR_OPT_CB: The packet received
5881 * BPF_SOCK_OPS_HDR_OPT_LEN_CB: Not useful because the
5882 * header has not been written.
5883 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB: The header and options have
5884 * been written so far.
5885 * BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: The SYNACK that concludes
5887 * BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: The ACK that concludes
5890 * bpf_load_hdr_opt() can also be used to read a particular option.
5892 __bpf_md_ptr(void *, skb_data);
5893 __bpf_md_ptr(void *, skb_data_end);
5894 __u32 skb_len; /* The total length of a packet.
5895 * It includes the header, options,
5898 __u32 skb_tcp_flags; /* tcp_flags of the header. It provides
5899 * an easy way to check for tcp_flags
5900 * without parsing skb_data.
5902 * In particular, the skb_tcp_flags
5903 * will still be available in
5904 * BPF_SOCK_OPS_HDR_OPT_LEN even though
5905 * the outgoing header has not
5910 /* Definitions for bpf_sock_ops_cb_flags */
5912 BPF_SOCK_OPS_RTO_CB_FLAG = (1<<0),
5913 BPF_SOCK_OPS_RETRANS_CB_FLAG = (1<<1),
5914 BPF_SOCK_OPS_STATE_CB_FLAG = (1<<2),
5915 BPF_SOCK_OPS_RTT_CB_FLAG = (1<<3),
5916 /* Call bpf for all received TCP headers. The bpf prog will be
5917 * called under sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5919 * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5920 * for the header option related helpers that will be useful
5921 * to the bpf programs.
5923 * It could be used at the client/active side (i.e. connect() side)
5924 * when the server told it that the server was in syncookie
5925 * mode and required the active side to resend the bpf-written
5926 * options. The active side can keep writing the bpf-options until
5927 * it received a valid packet from the server side to confirm
5928 * the earlier packet (and options) has been received. The later
5929 * example patch is using it like this at the active side when the
5930 * server is in syncookie mode.
5932 * The bpf prog will usually turn this off in the common cases.
5934 BPF_SOCK_OPS_PARSE_ALL_HDR_OPT_CB_FLAG = (1<<4),
5935 /* Call bpf when kernel has received a header option that
5936 * the kernel cannot handle. The bpf prog will be called under
5937 * sock_ops->op == BPF_SOCK_OPS_PARSE_HDR_OPT_CB.
5939 * Please refer to the comment in BPF_SOCK_OPS_PARSE_HDR_OPT_CB
5940 * for the header option related helpers that will be useful
5941 * to the bpf programs.
5943 BPF_SOCK_OPS_PARSE_UNKNOWN_HDR_OPT_CB_FLAG = (1<<5),
5944 /* Call bpf when the kernel is writing header options for the
5945 * outgoing packet. The bpf prog will first be called
5946 * to reserve space in a skb under
5947 * sock_ops->op == BPF_SOCK_OPS_HDR_OPT_LEN_CB. Then
5948 * the bpf prog will be called to write the header option(s)
5949 * under sock_ops->op == BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
5951 * Please refer to the comment in BPF_SOCK_OPS_HDR_OPT_LEN_CB
5952 * and BPF_SOCK_OPS_WRITE_HDR_OPT_CB for the header option
5953 * related helpers that will be useful to the bpf programs.
5955 * The kernel gets its chance to reserve space and write
5956 * options first before the BPF program does.
5958 BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (1<<6),
5959 /* Mask of all currently supported cb flags */
5960 BPF_SOCK_OPS_ALL_CB_FLAGS = 0x7F,
5963 /* List of known BPF sock_ops operators.
5964 * New entries can only be added at the end
5968 BPF_SOCK_OPS_TIMEOUT_INIT, /* Should return SYN-RTO value to use or
5969 * -1 if default value should be used
5971 BPF_SOCK_OPS_RWND_INIT, /* Should return initial advertized
5972 * window (in packets) or -1 if default
5973 * value should be used
5975 BPF_SOCK_OPS_TCP_CONNECT_CB, /* Calls BPF program right before an
5976 * active connection is initialized
5978 BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB, /* Calls BPF program when an
5979 * active connection is
5982 BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, /* Calls BPF program when a
5983 * passive connection is
5986 BPF_SOCK_OPS_NEEDS_ECN, /* If connection's congestion control
5989 BPF_SOCK_OPS_BASE_RTT, /* Get base RTT. The correct value is
5990 * based on the path and may be
5991 * dependent on the congestion control
5992 * algorithm. In general it indicates
5993 * a congestion threshold. RTTs above
5994 * this indicate congestion
5996 BPF_SOCK_OPS_RTO_CB, /* Called when an RTO has triggered.
5997 * Arg1: value of icsk_retransmits
5998 * Arg2: value of icsk_rto
5999 * Arg3: whether RTO has expired
6001 BPF_SOCK_OPS_RETRANS_CB, /* Called when skb is retransmitted.
6002 * Arg1: sequence number of 1st byte
6004 * Arg3: return value of
6005 * tcp_transmit_skb (0 => success)
6007 BPF_SOCK_OPS_STATE_CB, /* Called when TCP changes state.
6011 BPF_SOCK_OPS_TCP_LISTEN_CB, /* Called on listen(2), right after
6012 * socket transition to LISTEN state.
6014 BPF_SOCK_OPS_RTT_CB, /* Called on every RTT.
6016 BPF_SOCK_OPS_PARSE_HDR_OPT_CB, /* Parse the header option.
6017 * It will be called to handle
6018 * the packets received at
6019 * an already established
6022 * sock_ops->skb_data:
6023 * Referring to the received skb.
6024 * It covers the TCP header only.
6026 * bpf_load_hdr_opt() can also
6027 * be used to search for a
6028 * particular option.
6030 BPF_SOCK_OPS_HDR_OPT_LEN_CB, /* Reserve space for writing the
6031 * header option later in
6032 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
6033 * Arg1: bool want_cookie. (in
6034 * writing SYNACK only)
6036 * sock_ops->skb_data:
6037 * Not available because no header has
6040 * sock_ops->skb_tcp_flags:
6041 * The tcp_flags of the
6042 * outgoing skb. (e.g. SYN, ACK, FIN).
6044 * bpf_reserve_hdr_opt() should
6045 * be used to reserve space.
6047 BPF_SOCK_OPS_WRITE_HDR_OPT_CB, /* Write the header options
6048 * Arg1: bool want_cookie. (in
6049 * writing SYNACK only)
6051 * sock_ops->skb_data:
6052 * Referring to the outgoing skb.
6053 * It covers the TCP header
6054 * that has already been written
6055 * by the kernel and the
6056 * earlier bpf-progs.
6058 * sock_ops->skb_tcp_flags:
6059 * The tcp_flags of the outgoing
6060 * skb. (e.g. SYN, ACK, FIN).
6062 * bpf_store_hdr_opt() should
6063 * be used to write the
6066 * bpf_load_hdr_opt() can also
6067 * be used to search for a
6068 * particular option that
6069 * has already been written
6070 * by the kernel or the
6071 * earlier bpf-progs.
6075 /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
6076 * changes between the TCP and BPF versions. Ideally this should never happen.
6077 * If it does, we need to add code to convert them before calling
6078 * the BPF sock_ops function.
6081 BPF_TCP_ESTABLISHED = 1,
6091 BPF_TCP_CLOSING, /* Now a valid state */
6092 BPF_TCP_NEW_SYN_RECV,
6094 BPF_TCP_MAX_STATES /* Leave at the end! */
6098 TCP_BPF_IW = 1001, /* Set TCP initial congestion window */
6099 TCP_BPF_SNDCWND_CLAMP = 1002, /* Set sndcwnd_clamp */
6100 TCP_BPF_DELACK_MAX = 1003, /* Max delay ack in usecs */
6101 TCP_BPF_RTO_MIN = 1004, /* Min delay ack in usecs */
6102 /* Copy the SYN pkt to optval
6104 * BPF_PROG_TYPE_SOCK_OPS only. It is similar to the
6105 * bpf_getsockopt(TCP_SAVED_SYN) but it does not limit
6106 * to only getting from the saved_syn. It can either get the
6109 * 1. the just-received SYN packet (only available when writing the
6110 * SYNACK). It will be useful when it is not necessary to
6111 * save the SYN packet for latter use. It is also the only way
6112 * to get the SYN during syncookie mode because the syn
6113 * packet cannot be saved during syncookie.
6117 * 2. the earlier saved syn which was done by
6118 * bpf_setsockopt(TCP_SAVE_SYN).
6120 * The bpf_getsockopt(TCP_BPF_SYN*) option will hide where the
6121 * SYN packet is obtained.
6123 * If the bpf-prog does not need the IP[46] header, the
6124 * bpf-prog can avoid parsing the IP header by using
6125 * TCP_BPF_SYN. Otherwise, the bpf-prog can get both
6126 * IP[46] and TCP header by using TCP_BPF_SYN_IP.
6128 * >0: Total number of bytes copied
6129 * -ENOSPC: Not enough space in optval. Only optlen number of
6131 * -ENOENT: The SYN skb is not available now and the earlier SYN pkt
6132 * is not saved by setsockopt(TCP_SAVE_SYN).
6134 TCP_BPF_SYN = 1005, /* Copy the TCP header */
6135 TCP_BPF_SYN_IP = 1006, /* Copy the IP[46] and TCP header */
6136 TCP_BPF_SYN_MAC = 1007, /* Copy the MAC, IP[46], and TCP header */
6140 BPF_LOAD_HDR_OPT_TCP_SYN = (1ULL << 0),
6143 /* args[0] value during BPF_SOCK_OPS_HDR_OPT_LEN_CB and
6144 * BPF_SOCK_OPS_WRITE_HDR_OPT_CB.
6147 BPF_WRITE_HDR_TCP_CURRENT_MSS = 1, /* Kernel is finding the
6148 * total option spaces
6149 * required for an established
6150 * sk in order to calculate the
6151 * MSS. No skb is actually
6154 BPF_WRITE_HDR_TCP_SYNACK_COOKIE = 2, /* Kernel is in syncookie mode
6155 * when sending a SYN.
6159 struct bpf_perf_event_value {
6166 BPF_DEVCG_ACC_MKNOD = (1ULL << 0),
6167 BPF_DEVCG_ACC_READ = (1ULL << 1),
6168 BPF_DEVCG_ACC_WRITE = (1ULL << 2),
6172 BPF_DEVCG_DEV_BLOCK = (1ULL << 0),
6173 BPF_DEVCG_DEV_CHAR = (1ULL << 1),
6176 struct bpf_cgroup_dev_ctx {
6177 /* access_type encoded as (BPF_DEVCG_ACC_* << 16) | BPF_DEVCG_DEV_* */
6183 struct bpf_raw_tracepoint_args {
6187 /* DIRECT: Skip the FIB rules and go to FIB table associated with device
6188 * OUTPUT: Do lookup from egress perspective; default is ingress
6191 BPF_FIB_LOOKUP_DIRECT = (1U << 0),
6192 BPF_FIB_LOOKUP_OUTPUT = (1U << 1),
6196 BPF_FIB_LKUP_RET_SUCCESS, /* lookup successful */
6197 BPF_FIB_LKUP_RET_BLACKHOLE, /* dest is blackholed; can be dropped */
6198 BPF_FIB_LKUP_RET_UNREACHABLE, /* dest is unreachable; can be dropped */
6199 BPF_FIB_LKUP_RET_PROHIBIT, /* dest not allowed; can be dropped */
6200 BPF_FIB_LKUP_RET_NOT_FWDED, /* packet is not forwarded */
6201 BPF_FIB_LKUP_RET_FWD_DISABLED, /* fwding is not enabled on ingress */
6202 BPF_FIB_LKUP_RET_UNSUPP_LWT, /* fwd requires encapsulation */
6203 BPF_FIB_LKUP_RET_NO_NEIGH, /* no neighbor entry for nh */
6204 BPF_FIB_LKUP_RET_FRAG_NEEDED, /* fragmentation required to fwd */
6207 struct bpf_fib_lookup {
6208 /* input: network family for lookup (AF_INET, AF_INET6)
6209 * output: network family of egress nexthop
6213 /* set if lookup is to consider L4 data - e.g., FIB rules */
6218 union { /* used for MTU check */
6219 /* input to lookup */
6220 __u16 tot_len; /* L3 length from network hdr (iph->tot_len) */
6222 /* output: MTU value */
6225 /* input: L3 device index for lookup
6226 * output: device index from FIB lookup
6231 /* inputs to lookup */
6232 __u8 tos; /* AF_INET */
6233 __be32 flowinfo; /* AF_INET6, flow_label + priority */
6235 /* output: metric of fib result (IPv4/IPv6 only) */
6241 __u32 ipv6_src[4]; /* in6_addr; network order */
6244 /* input to bpf_fib_lookup, ipv{4,6}_dst is destination address in
6245 * network header. output: bpf_fib_lookup sets to gateway address
6246 * if FIB lookup returns gateway route
6250 __u32 ipv6_dst[4]; /* in6_addr; network order */
6254 __be16 h_vlan_proto;
6256 __u8 smac[6]; /* ETH_ALEN */
6257 __u8 dmac[6]; /* ETH_ALEN */
6260 struct bpf_redir_neigh {
6261 /* network family for lookup (AF_INET, AF_INET6) */
6263 /* network address of nexthop; skips fib lookup to find gateway */
6266 __u32 ipv6_nh[4]; /* in6_addr; network order */
6270 /* bpf_check_mtu flags*/
6271 enum bpf_check_mtu_flags {
6272 BPF_MTU_CHK_SEGS = (1U << 0),
6275 enum bpf_check_mtu_ret {
6276 BPF_MTU_CHK_RET_SUCCESS, /* check and lookup successful */
6277 BPF_MTU_CHK_RET_FRAG_NEEDED, /* fragmentation required to fwd */
6278 BPF_MTU_CHK_RET_SEGS_TOOBIG, /* GSO re-segmentation needed to fwd */
6281 enum bpf_task_fd_type {
6282 BPF_FD_TYPE_RAW_TRACEPOINT, /* tp name */
6283 BPF_FD_TYPE_TRACEPOINT, /* tp name */
6284 BPF_FD_TYPE_KPROBE, /* (symbol + offset) or addr */
6285 BPF_FD_TYPE_KRETPROBE, /* (symbol + offset) or addr */
6286 BPF_FD_TYPE_UPROBE, /* filename + offset */
6287 BPF_FD_TYPE_URETPROBE, /* filename + offset */
6291 BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG = (1U << 0),
6292 BPF_FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL = (1U << 1),
6293 BPF_FLOW_DISSECTOR_F_STOP_AT_ENCAP = (1U << 2),
6296 struct bpf_flow_keys {
6299 __u16 addr_proto; /* ETH_P_* of valid addrs */
6313 __u32 ipv6_src[4]; /* in6_addr; network order */
6314 __u32 ipv6_dst[4]; /* in6_addr; network order */
6321 struct bpf_func_info {
6326 #define BPF_LINE_INFO_LINE_NUM(line_col) ((line_col) >> 10)
6327 #define BPF_LINE_INFO_LINE_COL(line_col) ((line_col) & 0x3ff)
6329 struct bpf_line_info {
6331 __u32 file_name_off;
6336 struct bpf_spin_lock {
6343 } __attribute__((aligned(8)));
6346 __u32 write; /* Sysctl is being read (= 0) or written (= 1).
6347 * Allows 1,2,4-byte read, but no write.
6349 __u32 file_pos; /* Sysctl file position to read from, write to.
6350 * Allows 1,2,4-byte read an 4-byte write.
6354 struct bpf_sockopt {
6355 __bpf_md_ptr(struct bpf_sock *, sk);
6356 __bpf_md_ptr(void *, optval);
6357 __bpf_md_ptr(void *, optval_end);
6365 struct bpf_pidns_info {
6370 /* User accessible data for SK_LOOKUP programs. Add new fields at the end. */
6371 struct bpf_sk_lookup {
6373 __bpf_md_ptr(struct bpf_sock *, sk); /* Selected socket */
6374 __u64 cookie; /* Non-zero if socket was selected in PROG_TEST_RUN */
6377 __u32 family; /* Protocol family (AF_INET, AF_INET6) */
6378 __u32 protocol; /* IP protocol (IPPROTO_TCP, IPPROTO_UDP) */
6379 __u32 remote_ip4; /* Network byte order */
6380 __u32 remote_ip6[4]; /* Network byte order */
6381 __u32 remote_port; /* Network byte order */
6382 __u32 local_ip4; /* Network byte order */
6383 __u32 local_ip6[4]; /* Network byte order */
6384 __u32 local_port; /* Host byte order */
6385 __u32 ingress_ifindex; /* The arriving interface. Determined by inet_iif. */
6389 * struct btf_ptr is used for typed pointer representation; the
6390 * type id is used to render the pointer data as the appropriate type
6391 * via the bpf_snprintf_btf() helper described above. A flags field -
6392 * potentially to specify additional details about the BTF pointer
6393 * (rather than its mode of display) - is included for future use.
6394 * Display flags - BTF_F_* - are passed to bpf_snprintf_btf separately.
6399 __u32 flags; /* BTF ptr flags; unused at present. */
6403 * Flags to control bpf_snprintf_btf() behaviour.
6404 * - BTF_F_COMPACT: no formatting around type information
6405 * - BTF_F_NONAME: no struct/union member names/types
6406 * - BTF_F_PTR_RAW: show raw (unobfuscated) pointer values;
6407 * equivalent to %px.
6408 * - BTF_F_ZERO: show zero-valued struct/union members; they
6409 * are not displayed by default
6412 BTF_F_COMPACT = (1ULL << 0),
6413 BTF_F_NONAME = (1ULL << 1),
6414 BTF_F_PTR_RAW = (1ULL << 2),
6415 BTF_F_ZERO = (1ULL << 3),
6418 /* bpf_core_relo_kind encodes which aspect of captured field/type/enum value
6419 * has to be adjusted by relocations. It is emitted by llvm and passed to
6420 * libbpf and later to the kernel.
6422 enum bpf_core_relo_kind {
6423 BPF_CORE_FIELD_BYTE_OFFSET = 0, /* field byte offset */
6424 BPF_CORE_FIELD_BYTE_SIZE = 1, /* field size in bytes */
6425 BPF_CORE_FIELD_EXISTS = 2, /* field existence in target kernel */
6426 BPF_CORE_FIELD_SIGNED = 3, /* field signedness (0 - unsigned, 1 - signed) */
6427 BPF_CORE_FIELD_LSHIFT_U64 = 4, /* bitfield-specific left bitshift */
6428 BPF_CORE_FIELD_RSHIFT_U64 = 5, /* bitfield-specific right bitshift */
6429 BPF_CORE_TYPE_ID_LOCAL = 6, /* type ID in local BPF object */
6430 BPF_CORE_TYPE_ID_TARGET = 7, /* type ID in target kernel */
6431 BPF_CORE_TYPE_EXISTS = 8, /* type existence in target kernel */
6432 BPF_CORE_TYPE_SIZE = 9, /* type size in bytes */
6433 BPF_CORE_ENUMVAL_EXISTS = 10, /* enum value existence in target kernel */
6434 BPF_CORE_ENUMVAL_VALUE = 11, /* enum value integer value */
6438 * "struct bpf_core_relo" is used to pass relocation data form LLVM to libbpf
6439 * and from libbpf to the kernel.
6441 * CO-RE relocation captures the following data:
6442 * - insn_off - instruction offset (in bytes) within a BPF program that needs
6443 * its insn->imm field to be relocated with actual field info;
6444 * - type_id - BTF type ID of the "root" (containing) entity of a relocatable
6446 * - access_str_off - offset into corresponding .BTF string section. String
6447 * interpretation depends on specific relocation kind:
6448 * - for field-based relocations, string encodes an accessed field using
6449 * a sequence of field and array indices, separated by colon (:). It's
6450 * conceptually very close to LLVM's getelementptr ([0]) instruction's
6451 * arguments for identifying offset to a field.
6452 * - for type-based relocations, strings is expected to be just "0";
6453 * - for enum value-based relocations, string contains an index of enum
6454 * value within its enum type;
6455 * - kind - one of enum bpf_core_relo_kind;
6465 * struct sample *s = ...;
6466 * int *x = &s->a; // encoded as "0:0" (a is field #0)
6467 * int *y = &s->b[5]; // encoded as "0:1:0:5" (anon struct is field #1,
6468 * // b is field #0 inside anon struct, accessing elem #5)
6469 * int *z = &s[10]->b; // encoded as "10:1" (ptr is used as an array)
6471 * type_id for all relocs in this example will capture BTF type id of
6474 * Such relocation is emitted when using __builtin_preserve_access_index()
6475 * Clang built-in, passing expression that captures field address, e.g.:
6477 * bpf_probe_read(&dst, sizeof(dst),
6478 * __builtin_preserve_access_index(&src->a.b.c));
6480 * In this case Clang will emit field relocation recording necessary data to
6481 * be able to find offset of embedded `a.b.c` field within `src` struct.
6483 * [0] https://llvm.org/docs/LangRef.html#getelementptr-instruction
6485 struct bpf_core_relo {
6488 __u32 access_str_off;
6489 enum bpf_core_relo_kind kind;
6492 #endif /* _UAPI__LINUX_BPF_H__ */
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