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linux / linux / kernel / git / dhowells / linux-fs / refs/tags/rxrpc-iothread-20240305 / . / tools / include / uapi / linux / bpf.h
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/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#ifndef _UAPI__LINUX_BPF_H__
#define _UAPI__LINUX_BPF_H__
#include <linux/types.h>
#include <linux/bpf_common.h>
/* Extended instruction set based on top of classic BPF */
/* instruction classes */
#define BPF_JMP32 0x06 /* jmp mode in word width */
#define BPF_ALU64 0x07 /* alu mode in double word width */
/* ld/ldx fields */
#define BPF_DW 0x18 /* double word (64-bit) */
#define BPF_MEMSX 0x80 /* load with sign extension */
#define BPF_ATOMIC 0xc0 /* atomic memory ops - op type in immediate */
#define BPF_XADD 0xc0 /* exclusive add - legacy name */
/* alu/jmp fields */
#define BPF_MOV 0xb0 /* mov reg to reg */
#define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */
/* change endianness of a register */
#define BPF_END 0xd0 /* flags for endianness conversion: */
#define BPF_TO_LE 0x00 /* convert to little-endian */
#define BPF_TO_BE 0x08 /* convert to big-endian */
#define BPF_FROM_LE BPF_TO_LE
#define BPF_FROM_BE BPF_TO_BE
/* jmp encodings */
#define BPF_JNE 0x50 /* jump != */
#define BPF_JLT 0xa0 /* LT is unsigned, '<' */
#define BPF_JLE 0xb0 /* LE is unsigned, '<=' */
#define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */
#define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */
#define BPF_JSLT 0xc0 /* SLT is signed, '<' */
#define BPF_JSLE 0xd0 /* SLE is signed, '<=' */
#define BPF_CALL 0x80 /* function call */
#define BPF_EXIT 0x90 /* function return */
/* atomic op type fields (stored in immediate) */
#define BPF_FETCH 0x01 /* not an opcode on its own, used to build others */
#define BPF_XCHG (0xe0 | BPF_FETCH) /* atomic exchange */
#define BPF_CMPXCHG (0xf0 | BPF_FETCH) /* atomic compare-and-write */
/* Register numbers */
enum {
BPF_REG_0 = 0,
BPF_REG_1,
BPF_REG_2,
BPF_REG_3,
BPF_REG_4,
BPF_REG_5,
BPF_REG_6,
BPF_REG_7,
BPF_REG_8,
BPF_REG_9,
BPF_REG_10,
__MAX_BPF_REG,
};
/* BPF has 10 general purpose 64-bit registers and stack frame. */
#define MAX_BPF_REG __MAX_BPF_REG
struct bpf_insn {
__u8 code; /* opcode */
__u8 dst_reg:4; /* dest register */
__u8 src_reg:4; /* source register */
__s16 off; /* signed offset */
__s32 imm; /* signed immediate constant */
};
/* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
struct bpf_lpm_trie_key {
__u32 prefixlen; /* up to 32 for AF_INET, 128 for AF_INET6 */
__u8 data[0]; /* Arbitrary size */
};
struct bpf_cgroup_storage_key {
__u64 cgroup_inode_id; /* cgroup inode id */
__u32 attach_type; /* program attach type (enum bpf_attach_type) */
};
enum bpf_cgroup_iter_order {
BPF_CGROUP_ITER_ORDER_UNSPEC = 0,
BPF_CGROUP_ITER_SELF_ONLY, /* process only a single object. */
BPF_CGROUP_ITER_DESCENDANTS_PRE, /* walk descendants in pre-order. */
BPF_CGROUP_ITER_DESCENDANTS_POST, /* walk descendants in post-order. */
BPF_CGROUP_ITER_ANCESTORS_UP, /* walk ancestors upward. */
};
union bpf_iter_link_info {
struct {
__u32 map_fd;
} map;
struct {
enum bpf_cgroup_iter_order order;
/* At most one of cgroup_fd and cgroup_id can be non-zero. If
* both are zero, the walk starts from the default cgroup v2
* root. For walking v1 hierarchy, one should always explicitly
* specify cgroup_fd.
*/
__u32 cgroup_fd;
__u64 cgroup_id;
} cgroup;
/* Parameters of task iterators. */
struct {
__u32 tid;
__u32 pid;
__u32 pid_fd;
} task;
};
/* BPF syscall commands, see bpf(2) man-page for more details. */
/**
* DOC: eBPF Syscall Preamble
*
* The operation to be performed by the **bpf**\ () system call is determined
* by the *cmd* argument. Each operation takes an accompanying argument,
* provided via *attr*, which is a pointer to a union of type *bpf_attr* (see
* below). The size argument is the size of the union pointed to by *attr*.
*/
/**
* DOC: eBPF Syscall Commands
*
* BPF_MAP_CREATE
* Description
* Create a map and return a file descriptor that refers to the
* map. The close-on-exec file descriptor flag (see **fcntl**\ (2))
* is automatically enabled for the new file descriptor.
*
* Applying **close**\ (2) to the file descriptor returned by
* **BPF_MAP_CREATE** will delete the map (but see NOTES).
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_MAP_LOOKUP_ELEM
* Description
* Look up an element with a given *key* in the map referred to
* by the file descriptor *map_fd*.
*
* The *flags* argument may be specified as one of the
* following:
*
* **BPF_F_LOCK**
* Look up the value of a spin-locked map without
* returning the lock. This must be specified if the
* elements contain a spinlock.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_MAP_UPDATE_ELEM
* Description
* Create or update an element (key/value pair) in a specified map.
*
* The *flags* argument should be specified as one of the
* following:
*
* **BPF_ANY**
* Create a new element or update an existing element.
* **BPF_NOEXIST**
* Create a new element only if it did not exist.
* **BPF_EXIST**
* Update an existing element.
* **BPF_F_LOCK**
* Update a spin_lock-ed map element.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**,
* **E2BIG**, **EEXIST**, or **ENOENT**.
*
* **E2BIG**
* The number of elements in the map reached the
* *max_entries* limit specified at map creation time.
* **EEXIST**
* If *flags* specifies **BPF_NOEXIST** and the element
* with *key* already exists in the map.
* **ENOENT**
* If *flags* specifies **BPF_EXIST** and the element with
* *key* does not exist in the map.
*
* BPF_MAP_DELETE_ELEM
* Description
* Look up and delete an element by key in a specified map.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_MAP_GET_NEXT_KEY
* Description
* Look up an element by key in a specified map and return the key
* of the next element. Can be used to iterate over all elements
* in the map.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* The following cases can be used to iterate over all elements of
* the map:
*
* * If *key* is not found, the operation returns zero and sets
* the *next_key* pointer to the key of the first element.
* * If *key* is found, the operation returns zero and sets the
* *next_key* pointer to the key of the next element.
* * If *key* is the last element, returns -1 and *errno* is set
* to **ENOENT**.
*
* May set *errno* to **ENOMEM**, **EFAULT**, **EPERM**, or
* **EINVAL** on error.
*
* BPF_PROG_LOAD
* Description
* Verify and load an eBPF program, returning a new file
* descriptor associated with the program.
*
* Applying **close**\ (2) to the file descriptor returned by
* **BPF_PROG_LOAD** will unload the eBPF program (but see NOTES).
*
* The close-on-exec file descriptor flag (see **fcntl**\ (2)) is
* automatically enabled for the new file descriptor.
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_OBJ_PIN
* Description
* Pin an eBPF program or map referred by the specified *bpf_fd*
* to the provided *pathname* on the filesystem.
*
* The *pathname* argument must not contain a dot (".").
*
* On success, *pathname* retains a reference to the eBPF object,
* preventing deallocation of the object when the original
* *bpf_fd* is closed. This allow the eBPF object to live beyond
* **close**\ (\ *bpf_fd*\ ), and hence the lifetime of the parent
* process.
*
* Applying **unlink**\ (2) or similar calls to the *pathname*
* unpins the object from the filesystem, removing the reference.
* If no other file descriptors or filesystem nodes refer to the
* same object, it will be deallocated (see NOTES).
*
* The filesystem type for the parent directory of *pathname* must
* be **BPF_FS_MAGIC**.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_OBJ_GET
* Description
* Open a file descriptor for the eBPF object pinned to the
* specified *pathname*.
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_PROG_ATTACH
* Description
* Attach an eBPF program to a *target_fd* at the specified
* *attach_type* hook.
*
* The *attach_type* specifies the eBPF attachment point to
* attach the program to, and must be one of *bpf_attach_type*
* (see below).
*
* The *attach_bpf_fd* must be a valid file descriptor for a
* loaded eBPF program of a cgroup, flow dissector, LIRC, sockmap
* or sock_ops type corresponding to the specified *attach_type*.
*
* The *target_fd* must be a valid file descriptor for a kernel
* object which depends on the attach type of *attach_bpf_fd*:
*
* **BPF_PROG_TYPE_CGROUP_DEVICE**,
* **BPF_PROG_TYPE_CGROUP_SKB**,
* **BPF_PROG_TYPE_CGROUP_SOCK**,
* **BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
* **BPF_PROG_TYPE_CGROUP_SOCKOPT**,
* **BPF_PROG_TYPE_CGROUP_SYSCTL**,
* **BPF_PROG_TYPE_SOCK_OPS**
*
* Control Group v2 hierarchy with the eBPF controller
* enabled. Requires the kernel to be compiled with
* **CONFIG_CGROUP_BPF**.
*
* **BPF_PROG_TYPE_FLOW_DISSECTOR**
*
* Network namespace (eg /proc/self/ns/net).
*
* **BPF_PROG_TYPE_LIRC_MODE2**
*
* LIRC device path (eg /dev/lircN). Requires the kernel
* to be compiled with **CONFIG_BPF_LIRC_MODE2**.
*
* **BPF_PROG_TYPE_SK_SKB**,
* **BPF_PROG_TYPE_SK_MSG**
*
* eBPF map of socket type (eg **BPF_MAP_TYPE_SOCKHASH**).
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_PROG_DETACH
* Description
* Detach the eBPF program associated with the *target_fd* at the
* hook specified by *attach_type*. The program must have been
* previously attached using **BPF_PROG_ATTACH**.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_PROG_TEST_RUN
* Description
* Run the eBPF program associated with the *prog_fd* a *repeat*
* number of times against a provided program context *ctx_in* and
* data *data_in*, and return the modified program context
* *ctx_out*, *data_out* (for example, packet data), result of the
* execution *retval*, and *duration* of the test run.
*
* The sizes of the buffers provided as input and output
* parameters *ctx_in*, *ctx_out*, *data_in*, and *data_out* must
* be provided in the corresponding variables *ctx_size_in*,
* *ctx_size_out*, *data_size_in*, and/or *data_size_out*. If any
* of these parameters are not provided (ie set to NULL), the
* corresponding size field must be zero.
*
* Some program types have particular requirements:
*
* **BPF_PROG_TYPE_SK_LOOKUP**
* *data_in* and *data_out* must be NULL.
*
* **BPF_PROG_TYPE_RAW_TRACEPOINT**,
* **BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE**
*
* *ctx_out*, *data_in* and *data_out* must be NULL.
* *repeat* must be zero.
*
* BPF_PROG_RUN is an alias for BPF_PROG_TEST_RUN.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* **ENOSPC**
* Either *data_size_out* or *ctx_size_out* is too small.
* **ENOTSUPP**
* This command is not supported by the program type of
* the program referred to by *prog_fd*.
*
* BPF_PROG_GET_NEXT_ID
* Description
* Fetch the next eBPF program currently loaded into the kernel.
*
* Looks for the eBPF program with an id greater than *start_id*
* and updates *next_id* on success. If no other eBPF programs
* remain with ids higher than *start_id*, returns -1 and sets
* *errno* to **ENOENT**.
*
* Return
* Returns zero on success. On error, or when no id remains, -1
* is returned and *errno* is set appropriately.
*
* BPF_MAP_GET_NEXT_ID
* Description
* Fetch the next eBPF map currently loaded into the kernel.
*
* Looks for the eBPF map with an id greater than *start_id*
* and updates *next_id* on success. If no other eBPF maps
* remain with ids higher than *start_id*, returns -1 and sets
* *errno* to **ENOENT**.
*
* Return
* Returns zero on success. On error, or when no id remains, -1
* is returned and *errno* is set appropriately.
*
* BPF_PROG_GET_FD_BY_ID
* Description
* Open a file descriptor for the eBPF program corresponding to
* *prog_id*.
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_MAP_GET_FD_BY_ID
* Description
* Open a file descriptor for the eBPF map corresponding to
* *map_id*.
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_OBJ_GET_INFO_BY_FD
* Description
* Obtain information about the eBPF object corresponding to
* *bpf_fd*.
*
* Populates up to *info_len* bytes of *info*, which will be in
* one of the following formats depending on the eBPF object type
* of *bpf_fd*:
*
* * **struct bpf_prog_info**
* * **struct bpf_map_info**
* * **struct bpf_btf_info**
* * **struct bpf_link_info**
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_PROG_QUERY
* Description
* Obtain information about eBPF programs associated with the
* specified *attach_type* hook.
*
* The *target_fd* must be a valid file descriptor for a kernel
* object which depends on the attach type of *attach_bpf_fd*:
*
* **BPF_PROG_TYPE_CGROUP_DEVICE**,
* **BPF_PROG_TYPE_CGROUP_SKB**,
* **BPF_PROG_TYPE_CGROUP_SOCK**,
* **BPF_PROG_TYPE_CGROUP_SOCK_ADDR**,
* **BPF_PROG_TYPE_CGROUP_SOCKOPT**,
* **BPF_PROG_TYPE_CGROUP_SYSCTL**,
* **BPF_PROG_TYPE_SOCK_OPS**
*
* Control Group v2 hierarchy with the eBPF controller
* enabled. Requires the kernel to be compiled with
* **CONFIG_CGROUP_BPF**.
*
* **BPF_PROG_TYPE_FLOW_DISSECTOR**
*
* Network namespace (eg /proc/self/ns/net).
*
* **BPF_PROG_TYPE_LIRC_MODE2**
*
* LIRC device path (eg /dev/lircN). Requires the kernel
* to be compiled with **CONFIG_BPF_LIRC_MODE2**.
*
* **BPF_PROG_QUERY** always fetches the number of programs
* attached and the *attach_flags* which were used to attach those
* programs. Additionally, if *prog_ids* is nonzero and the number
* of attached programs is less than *prog_cnt*, populates
* *prog_ids* with the eBPF program ids of the programs attached
* at *target_fd*.
*
* The following flags may alter the result:
*
* **BPF_F_QUERY_EFFECTIVE**
* Only return information regarding programs which are
* currently effective at the specified *target_fd*.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_RAW_TRACEPOINT_OPEN
* Description
* Attach an eBPF program to a tracepoint *name* to access kernel
* internal arguments of the tracepoint in their raw form.
*
* The *prog_fd* must be a valid file descriptor associated with
* a loaded eBPF program of type **BPF_PROG_TYPE_RAW_TRACEPOINT**.
*
* No ABI guarantees are made about the content of tracepoint
* arguments exposed to the corresponding eBPF program.
*
* Applying **close**\ (2) to the file descriptor returned by
* **BPF_RAW_TRACEPOINT_OPEN** will delete the map (but see NOTES).
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_BTF_LOAD
* Description
* Verify and load BPF Type Format (BTF) metadata into the kernel,
* returning a new file descriptor associated with the metadata.
* BTF is described in more detail at
* https://www.kernel.org/doc/html/latest/bpf/btf.html.
*
* The *btf* parameter must point to valid memory providing
* *btf_size* bytes of BTF binary metadata.
*
* The returned file descriptor can be passed to other **bpf**\ ()
* subcommands such as **BPF_PROG_LOAD** or **BPF_MAP_CREATE** to
* associate the BTF with those objects.
*
* Similar to **BPF_PROG_LOAD**, **BPF_BTF_LOAD** has optional
* parameters to specify a *btf_log_buf*, *btf_log_size* and
* *btf_log_level* which allow the kernel to return freeform log
* output regarding the BTF verification process.
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_BTF_GET_FD_BY_ID
* Description
* Open a file descriptor for the BPF Type Format (BTF)
* corresponding to *btf_id*.
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_TASK_FD_QUERY
* Description
* Obtain information about eBPF programs associated with the
* target process identified by *pid* and *fd*.
*
* If the *pid* and *fd* are associated with a tracepoint, kprobe
* or uprobe perf event, then the *prog_id* and *fd_type* will
* be populated with the eBPF program id and file descriptor type
* of type **bpf_task_fd_type**. If associated with a kprobe or
* uprobe, the *probe_offset* and *probe_addr* will also be
* populated. Optionally, if *buf* is provided, then up to
* *buf_len* bytes of *buf* will be populated with the name of
* the tracepoint, kprobe or uprobe.
*
* The resulting *prog_id* may be introspected in deeper detail
* using **BPF_PROG_GET_FD_BY_ID** and **BPF_OBJ_GET_INFO_BY_FD**.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_MAP_LOOKUP_AND_DELETE_ELEM
* Description
* Look up an element with the given *key* in the map referred to
* by the file descriptor *fd*, and if found, delete the element.
*
* For **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map
* types, the *flags* argument needs to be set to 0, but for other
* map types, it may be specified as:
*
* **BPF_F_LOCK**
* Look up and delete the value of a spin-locked map
* without returning the lock. This must be specified if
* the elements contain a spinlock.
*
* The **BPF_MAP_TYPE_QUEUE** and **BPF_MAP_TYPE_STACK** map types
* implement this command as a "pop" operation, deleting the top
* element rather than one corresponding to *key*.
* The *key* and *key_len* parameters should be zeroed when
* issuing this operation for these map types.
*
* This command is only valid for the following map types:
* * **BPF_MAP_TYPE_QUEUE**
* * **BPF_MAP_TYPE_STACK**
* * **BPF_MAP_TYPE_HASH**
* * **BPF_MAP_TYPE_PERCPU_HASH**
* * **BPF_MAP_TYPE_LRU_HASH**
* * **BPF_MAP_TYPE_LRU_PERCPU_HASH**
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_MAP_FREEZE
* Description
* Freeze the permissions of the specified map.
*
* Write permissions may be frozen by passing zero *flags*.
* Upon success, no future syscall invocations may alter the
* map state of *map_fd*. Write operations from eBPF programs
* are still possible for a frozen map.
*
* Not supported for maps of type **BPF_MAP_TYPE_STRUCT_OPS**.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_BTF_GET_NEXT_ID
* Description
* Fetch the next BPF Type Format (BTF) object currently loaded
* into the kernel.
*
* Looks for the BTF object with an id greater than *start_id*
* and updates *next_id* on success. If no other BTF objects
* remain with ids higher than *start_id*, returns -1 and sets
* *errno* to **ENOENT**.
*
* Return
* Returns zero on success. On error, or when no id remains, -1
* is returned and *errno* is set appropriately.
*
* BPF_MAP_LOOKUP_BATCH
* Description
* Iterate and fetch multiple elements in a map.
*
* Two opaque values are used to manage batch operations,
* *in_batch* and *out_batch*. Initially, *in_batch* must be set
* to NULL to begin the batched operation. After each subsequent
* **BPF_MAP_LOOKUP_BATCH**, the caller should pass the resultant
* *out_batch* as the *in_batch* for the next operation to
* continue iteration from the current point.
*
* The *keys* and *values* are output parameters which must point
* to memory large enough to hold *count* items based on the key
* and value size of the map *map_fd*. The *keys* buffer must be
* of *key_size* * *count*. The *values* buffer must be of
* *value_size* * *count*.
*
* The *elem_flags* argument may be specified as one of the
* following:
*
* **BPF_F_LOCK**
* Look up the value of a spin-locked map without
* returning the lock. This must be specified if the
* elements contain a spinlock.
*
* On success, *count* elements from the map are copied into the
* user buffer, with the keys copied into *keys* and the values
* copied into the corresponding indices in *values*.
*
* If an error is returned and *errno* is not **EFAULT**, *count*
* is set to the number of successfully processed elements.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* May set *errno* to **ENOSPC** to indicate that *keys* or
* *values* is too small to dump an entire bucket during
* iteration of a hash-based map type.
*
* BPF_MAP_LOOKUP_AND_DELETE_BATCH
* Description
* Iterate and delete all elements in a map.
*
* This operation has the same behavior as
* **BPF_MAP_LOOKUP_BATCH** with two exceptions:
*
* * Every element that is successfully returned is also deleted
* from the map. This is at least *count* elements. Note that
* *count* is both an input and an output parameter.
* * Upon returning with *errno* set to **EFAULT**, up to
* *count* elements may be deleted without returning the keys
* and values of the deleted elements.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_MAP_UPDATE_BATCH
* Description
* Update multiple elements in a map by *key*.
*
* The *keys* and *values* are input parameters which must point
* to memory large enough to hold *count* items based on the key
* and value size of the map *map_fd*. The *keys* buffer must be
* of *key_size* * *count*. The *values* buffer must be of
* *value_size* * *count*.
*
* Each element specified in *keys* is sequentially updated to the
* value in the corresponding index in *values*. The *in_batch*
* and *out_batch* parameters are ignored and should be zeroed.
*
* The *elem_flags* argument should be specified as one of the
* following:
*
* **BPF_ANY**
* Create new elements or update a existing elements.
* **BPF_NOEXIST**
* Create new elements only if they do not exist.
* **BPF_EXIST**
* Update existing elements.
* **BPF_F_LOCK**
* Update spin_lock-ed map elements. This must be
* specified if the map value contains a spinlock.
*
* On success, *count* elements from the map are updated.
*
* If an error is returned and *errno* is not **EFAULT**, *count*
* is set to the number of successfully processed elements.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* May set *errno* to **EINVAL**, **EPERM**, **ENOMEM**, or
* **E2BIG**. **E2BIG** indicates that the number of elements in
* the map reached the *max_entries* limit specified at map
* creation time.
*
* May set *errno* to one of the following error codes under
* specific circumstances:
*
* **EEXIST**
* If *flags* specifies **BPF_NOEXIST** and the element
* with *key* already exists in the map.
* **ENOENT**
* If *flags* specifies **BPF_EXIST** and the element with
* *key* does not exist in the map.
*
* BPF_MAP_DELETE_BATCH
* Description
* Delete multiple elements in a map by *key*.
*
* The *keys* parameter is an input parameter which must point
* to memory large enough to hold *count* items based on the key
* size of the map *map_fd*, that is, *key_size* * *count*.
*
* Each element specified in *keys* is sequentially deleted. The
* *in_batch*, *out_batch*, and *values* parameters are ignored
* and should be zeroed.
*
* The *elem_flags* argument may be specified as one of the
* following:
*
* **BPF_F_LOCK**
* Look up the value of a spin-locked map without
* returning the lock. This must be specified if the
* elements contain a spinlock.
*
* On success, *count* elements from the map are updated.
*
* If an error is returned and *errno* is not **EFAULT**, *count*
* is set to the number of successfully processed elements. If
* *errno* is **EFAULT**, up to *count* elements may be been
* deleted.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_LINK_CREATE
* Description
* Attach an eBPF program to a *target_fd* at the specified
* *attach_type* hook and return a file descriptor handle for
* managing the link.
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_LINK_UPDATE
* Description
* Update the eBPF program in the specified *link_fd* to
* *new_prog_fd*.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_LINK_GET_FD_BY_ID
* Description
* Open a file descriptor for the eBPF Link corresponding to
* *link_id*.
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_LINK_GET_NEXT_ID
* Description
* Fetch the next eBPF link currently loaded into the kernel.
*
* Looks for the eBPF link with an id greater than *start_id*
* and updates *next_id* on success. If no other eBPF links
* remain with ids higher than *start_id*, returns -1 and sets
* *errno* to **ENOENT**.
*
* Return
* Returns zero on success. On error, or when no id remains, -1
* is returned and *errno* is set appropriately.
*
* BPF_ENABLE_STATS
* Description
* Enable eBPF runtime statistics gathering.
*
* Runtime statistics gathering for the eBPF runtime is disabled
* by default to minimize the corresponding performance overhead.
* This command enables statistics globally.
*
* Multiple programs may independently enable statistics.
* After gathering the desired statistics, eBPF runtime statistics
* may be disabled again by calling **close**\ (2) for the file
* descriptor returned by this function. Statistics will only be
* disabled system-wide when all outstanding file descriptors
* returned by prior calls for this subcommand are closed.
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_ITER_CREATE
* Description
* Create an iterator on top of the specified *link_fd* (as
* previously created using **BPF_LINK_CREATE**) and return a
* file descriptor that can be used to trigger the iteration.
*
* If the resulting file descriptor is pinned to the filesystem
* using **BPF_OBJ_PIN**, then subsequent **read**\ (2) syscalls
* for that path will trigger the iterator to read kernel state
* using the eBPF program attached to *link_fd*.
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* BPF_LINK_DETACH
* Description
* Forcefully detach the specified *link_fd* from its
* corresponding attachment point.
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_PROG_BIND_MAP
* Description
* Bind a map to the lifetime of an eBPF program.
*
* The map identified by *map_fd* is bound to the program
* identified by *prog_fd* and only released when *prog_fd* is
* released. This may be used in cases where metadata should be
* associated with a program which otherwise does not contain any
* references to the map (for example, embedded in the eBPF
* program instructions).
*
* Return
* Returns zero on success. On error, -1 is returned and *errno*
* is set appropriately.
*
* BPF_TOKEN_CREATE
* Description
* Create BPF token with embedded information about what
* BPF-related functionality it allows:
* - a set of allowed bpf() syscall commands;
* - a set of allowed BPF map types to be created with
* BPF_MAP_CREATE command, if BPF_MAP_CREATE itself is allowed;
* - a set of allowed BPF program types and BPF program attach
* types to be loaded with BPF_PROG_LOAD command, if
* BPF_PROG_LOAD itself is allowed.
*
* BPF token is created (derived) from an instance of BPF FS,
* assuming it has necessary delegation mount options specified.
* This BPF token can be passed as an extra parameter to various
* bpf() syscall commands to grant BPF subsystem functionality to
* unprivileged processes.
*
* When created, BPF token is "associated" with the owning
* user namespace of BPF FS instance (super block) that it was
* derived from, and subsequent BPF operations performed with
* BPF token would be performing capabilities checks (i.e.,
* CAP_BPF, CAP_PERFMON, CAP_NET_ADMIN, CAP_SYS_ADMIN) within
* that user namespace. Without BPF token, such capabilities
* have to be granted in init user namespace, making bpf()
* syscall incompatible with user namespace, for the most part.
*
* Return
* A new file descriptor (a nonnegative integer), or -1 if an
* error occurred (in which case, *errno* is set appropriately).
*
* NOTES
* eBPF objects (maps and programs) can be shared between processes.
*
* * After **fork**\ (2), the child inherits file descriptors
* referring to the same eBPF objects.
* * File descriptors referring to eBPF objects can be transferred over
* **unix**\ (7) domain sockets.
* * File descriptors referring to eBPF objects can be duplicated in the
* usual way, using **dup**\ (2) and similar calls.
* * File descriptors referring to eBPF objects can be pinned to the
* filesystem using the **BPF_OBJ_PIN** command of **bpf**\ (2).
*
* An eBPF object is deallocated only after all file descriptors referring
* to the object have been closed and no references remain pinned to the
* filesystem or attached (for example, bound to a program or device).
*/
enum bpf_cmd {
BPF_MAP_CREATE,
BPF_MAP_LOOKUP_ELEM,
BPF_MAP_UPDATE_ELEM,
BPF_MAP_DELETE_ELEM,
BPF_MAP_GET_NEXT_KEY,
BPF_PROG_LOAD,
BPF_OBJ_PIN,
BPF_OBJ_GET,
BPF_PROG_ATTACH,
BPF_PROG_DETACH,
BPF_PROG_TEST_RUN,
BPF_PROG_RUN = BPF_PROG_TEST_RUN,
BPF_PROG_GET_NEXT_ID,
BPF_MAP_GET_NEXT_ID,
BPF_PROG_GET_FD_BY_ID,
BPF_MAP_GET_FD_BY_ID,
BPF_OBJ_GET_INFO_BY_FD,
BPF_PROG_QUERY,
BPF_RAW_TRACEPOINT_OPEN,
BPF_BTF_LOAD,
BPF_BTF_GET_FD_BY_ID,
BPF_TASK_FD_QUERY,
BPF_MAP_LOOKUP_AND_DELETE_ELEM,
BPF_MAP_FREEZE,
BPF_BTF_GET_NEXT_ID,
BPF_MAP_LOOKUP_BATCH,
BPF_MAP_LOOKUP_AND_DELETE_BATCH,
BPF_MAP_UPDATE_BATCH,
BPF_MAP_DELETE_BATCH,
BPF_LINK_CREATE,
BPF_LINK_UPDATE,
BPF_LINK_GET_FD_BY_ID,
BPF_LINK_GET_NEXT_ID,
BPF_ENABLE_STATS,
BPF_ITER_CREATE,
BPF_LINK_DETACH,
BPF_PROG_BIND_MAP,
BPF_TOKEN_CREATE,
__MAX_BPF_CMD,
};
enum bpf_map_type {
BPF_MAP_TYPE_UNSPEC,
BPF_MAP_TYPE_HASH,
BPF_MAP_TYPE_ARRAY,
BPF_MAP_TYPE_PROG_ARRAY,
BPF_MAP_TYPE_PERF_EVENT_ARRAY,
BPF_MAP_TYPE_PERCPU_HASH,
BPF_MAP_TYPE_PERCPU_ARRAY,
BPF_MAP_TYPE_STACK_TRACE,
BPF_MAP_TYPE_CGROUP_ARRAY,
BPF_MAP_TYPE_LRU_HASH,
BPF_MAP_TYPE_LRU_PERCPU_HASH,
BPF_MAP_TYPE_LPM_TRIE,
BPF_MAP_TYPE_ARRAY_OF_MAPS,
BPF_MAP_TYPE_HASH_OF_MAPS,
BPF_MAP_TYPE_DEVMAP,
BPF_MAP_TYPE_SOCKMAP,
BPF_MAP_TYPE_CPUMAP,
BPF_MAP_TYPE_XSKMAP,
BPF_MAP_TYPE_SOCKHASH,
BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED,
/* BPF_MAP_TYPE_CGROUP_STORAGE is available to bpf programs attaching
* to a cgroup. The newer BPF_MAP_TYPE_CGRP_STORAGE is available to
* both cgroup-attached and other progs and supports all functionality
* provided by BPF_MAP_TYPE_CGROUP_STORAGE. So mark
* BPF_MAP_TYPE_CGROUP_STORAGE deprecated.
*/
BPF_MAP_TYPE_CGROUP_STORAGE = BPF_MAP_TYPE_CGROUP_STORAGE_DEPRECATED,
BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE_DEPRECATED,
/* BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE is available to bpf programs
* attaching to a cgroup. The new mechanism (BPF_MAP_TYPE_CGRP_STORAGE +
* local percpu kptr) supports all BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE
* functionality and more. So mark * BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE
* deprecated.
*/
BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE = BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE_DEPRECATED,
BPF_MAP_TYPE_QUEUE,
BPF_MAP_TYPE_STACK,
BPF_MAP_TYPE_SK_STORAGE,
BPF_MAP_TYPE_DEVMAP_HASH,
BPF_MAP_TYPE_STRUCT_OPS,
BPF_MAP_TYPE_RINGBUF,
BPF_MAP_TYPE_INODE_STORAGE,
BPF_MAP_TYPE_TASK_STORAGE,
BPF_MAP_TYPE_BLOOM_FILTER,
BPF_MAP_TYPE_USER_RINGBUF,
BPF_MAP_TYPE_CGRP_STORAGE,
__MAX_BPF_MAP_TYPE
};
/* Note that tracing related programs such as
* BPF_PROG_TYPE_{KPROBE,TRACEPOINT,PERF_EVENT,RAW_TRACEPOINT}
* are not subject to a stable API since kernel internal data
* structures can change from release to release and may
* therefore break existing tracing BPF programs. Tracing BPF
* programs correspond to /a/ specific kernel which is to be
* analyzed, and not /a/ specific kernel /and/ all future ones.
*/
enum bpf_prog_type {
BPF_PROG_TYPE_UNSPEC,
BPF_PROG_TYPE_SOCKET_FILTER,
BPF_PROG_TYPE_KPROBE,
BPF_PROG_TYPE_SCHED_CLS,
BPF_PROG_TYPE_SCHED_ACT,
BPF_PROG_TYPE_TRACEPOINT,
BPF_PROG_TYPE_XDP,
BPF_PROG_TYPE_PERF_EVENT,
BPF_PROG_TYPE_CGROUP_SKB,
BPF_PROG_TYPE_CGROUP_SOCK,
BPF_PROG_TYPE_LWT_IN,
BPF_PROG_TYPE_LWT_OUT,
BPF_PROG_TYPE_LWT_XMIT,
BPF_PROG_TYPE_SOCK_OPS,
BPF_PROG_TYPE_SK_SKB,
BPF_PROG_TYPE_CGROUP_DEVICE,
BPF_PROG_TYPE_SK_MSG,
BPF_PROG_TYPE_RAW_TRACEPOINT,
BPF_PROG_TYPE_CGROUP_SOCK_ADDR,
BPF_PROG_TYPE_LWT_SEG6LOCAL,
BPF_PROG_TYPE_LIRC_MODE2,
BPF_PROG_TYPE_SK_REUSEPORT,
BPF_PROG_TYPE_FLOW_DISSECTOR,
BPF_PROG_TYPE_CGROUP_SYSCTL,
BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
BPF_PROG_TYPE_CGROUP_SOCKOPT,
BPF_PROG_TYPE_TRACING,
BPF_PROG_TYPE_STRUCT_OPS,
BPF_PROG_TYPE_EXT,
BPF_PROG_TYPE_LSM,
BPF_PROG_TYPE_SK_LOOKUP,
BPF_PROG_TYPE_SYSCALL, /* a program that can execute syscalls */
BPF_PROG_TYPE_NETFILTER,
__MAX_BPF_PROG_TYPE
};
enum bpf_attach_type {
BPF_CGROUP_INET_INGRESS,
BPF_CGROUP_INET_EGRESS,
BPF_CGROUP_INET_SOCK_CREATE,
BPF_CGROUP_SOCK_OPS,
BPF_SK_SKB_STREAM_PARSER,
BPF_SK_SKB_STREAM_VERDICT,
BPF_CGROUP_DEVICE,
BPF_SK_MSG_VERDICT,
BPF_CGROUP_INET4_BIND,
BPF_CGROUP_INET6_BIND,
BPF_CGROUP_INET4_CONNECT,
BPF_CGROUP_INET6_CONNECT,
BPF_CGROUP_INET4_POST_BIND,
BPF_CGROUP_INET6_POST_BIND,
BPF_CGROUP_UDP4_SENDMSG,
BPF_CGROUP_UDP6_SENDMSG,
BPF_LIRC_MODE2,
BPF_FLOW_DISSECTOR,
BPF_CGROUP_SYSCTL,
BPF_CGROUP_UDP4_RECVMSG,
BPF_CGROUP_UDP6_RECVMSG,
BPF_CGROUP_GETSOCKOPT,
BPF_CGROUP_SETSOCKOPT,
BPF_TRACE_RAW_TP,
BPF_TRACE_FENTRY,
BPF_TRACE_FEXIT,
BPF_MODIFY_RETURN,
BPF_LSM_MAC,
BPF_TRACE_ITER,
BPF_CGROUP_INET4_GETPEERNAME,
BPF_CGROUP_INET6_GETPEERNAME,
BPF_CGROUP_INET4_GETSOCKNAME,
BPF_CGROUP_INET6_GETSOCKNAME,
BPF_XDP_DEVMAP,
BPF_CGROUP_INET_SOCK_RELEASE,
BPF_XDP_CPUMAP,
BPF_SK_LOOKUP,
BPF_XDP,
BPF_SK_SKB_VERDICT,
BPF_SK_REUSEPORT_SELECT,
BPF_SK_REUSEPORT_SELECT_OR_MIGRATE,
BPF_PERF_EVENT,
BPF_TRACE_KPROBE_MULTI,
BPF_LSM_CGROUP,
BPF_STRUCT_OPS,
BPF_NETFILTER,
BPF_TCX_INGRESS,
BPF_TCX_EGRESS,
BPF_TRACE_UPROBE_MULTI,
BPF_CGROUP_UNIX_CONNECT,
BPF_CGROUP_UNIX_SENDMSG,
BPF_CGROUP_UNIX_RECVMSG,
BPF_CGROUP_UNIX_GETPEERNAME,
BPF_CGROUP_UNIX_GETSOCKNAME,
BPF_NETKIT_PRIMARY,
BPF_NETKIT_PEER,
__MAX_BPF_ATTACH_TYPE
};
#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE
enum bpf_link_type {
BPF_LINK_TYPE_UNSPEC = 0,
BPF_LINK_TYPE_RAW_TRACEPOINT = 1,
BPF_LINK_TYPE_TRACING = 2,
BPF_LINK_TYPE_CGROUP = 3,
BPF_LINK_TYPE_ITER = 4,
BPF_LINK_TYPE_NETNS = 5,
BPF_LINK_TYPE_XDP = 6,
BPF_LINK_TYPE_PERF_EVENT = 7,
BPF_LINK_TYPE_KPROBE_MULTI = 8,
BPF_LINK_TYPE_STRUCT_OPS = 9,
BPF_LINK_TYPE_NETFILTER = 10,
BPF_LINK_TYPE_TCX = 11,
BPF_LINK_TYPE_UPROBE_MULTI = 12,
BPF_LINK_TYPE_NETKIT = 13,
__MAX_BPF_LINK_TYPE,
};
#define MAX_BPF_LINK_TYPE __MAX_BPF_LINK_TYPE
enum bpf_perf_event_type {
BPF_PERF_EVENT_UNSPEC = 0,
BPF_PERF_EVENT_UPROBE = 1,
BPF_PERF_EVENT_URETPROBE = 2,
BPF_PERF_EVENT_KPROBE = 3,
BPF_PERF_EVENT_KRETPROBE = 4,
BPF_PERF_EVENT_TRACEPOINT = 5,
BPF_PERF_EVENT_EVENT = 6,
};
/* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
*
* NONE(default): No further bpf programs allowed in the subtree.
*
* BPF_F_ALLOW_OVERRIDE: If a sub-cgroup installs some bpf program,
* the program in this cgroup yields to sub-cgroup program.
*
* BPF_F_ALLOW_MULTI: If a sub-cgroup installs some bpf program,
* that cgroup program gets run in addition to the program in this cgroup.
*
* Only one program is allowed to be attached to a cgroup with
* NONE or BPF_F_ALLOW_OVERRIDE flag.
* Attaching another program on top of NONE or BPF_F_ALLOW_OVERRIDE will
* release old program and attach the new one. Attach flags has to match.
*
* Multiple programs are allowed to be attached to a cgroup with
* BPF_F_ALLOW_MULTI flag. They are executed in FIFO order
* (those that were attached first, run first)
* The programs of sub-cgroup are executed first, then programs of
* this cgroup and then programs of parent cgroup.
* When children program makes decision (like picking TCP CA or sock bind)
* parent program has a chance to override it.
*
* With BPF_F_ALLOW_MULTI a new program is added to the end of the list of
* programs for a cgroup. Though it's possible to replace an old program at
* any position by also specifying BPF_F_REPLACE flag and position itself in
* replace_bpf_fd attribute. Old program at this position will be released.
*
* A cgroup with MULTI or OVERRIDE flag allows any attach flags in sub-cgroups.
* A cgroup with NONE doesn't allow any programs in sub-cgroups.
* Ex1:
* cgrp1 (MULTI progs A, B) ->
* cgrp2 (OVERRIDE prog C) ->
* cgrp3 (MULTI prog D) ->
* cgrp4 (OVERRIDE prog E) ->
* cgrp5 (NONE prog F)
* the event in cgrp5 triggers execution of F,D,A,B in that order.
* if prog F is detached, the execution is E,D,A,B
* if prog F and D are detached, the execution is E,A,B
* if prog F, E and D are detached, the execution is C,A,B
*
* All eligible programs are executed regardless of return code from
* earlier programs.
*/
#define BPF_F_ALLOW_OVERRIDE (1U << 0)
#define BPF_F_ALLOW_MULTI (1U << 1)
/* Generic attachment flags. */
#define BPF_F_REPLACE (1U << 2)
#define BPF_F_BEFORE (1U << 3)
#define BPF_F_AFTER (1U << 4)
#define BPF_F_ID (1U << 5)
#define BPF_F_LINK BPF_F_LINK /* 1 << 13 */
/* If BPF_F_STRICT_ALIGNMENT is used in BPF_PROG_LOAD command, the
* verifier will perform strict alignment checking as if the kernel
* has been built with CONFIG_EFFICIENT_UNALIGNED_ACCESS not set,
* and NET_IP_ALIGN defined to 2.
*/
#define BPF_F_STRICT_ALIGNMENT (1U << 0)
/* If BPF_F_ANY_ALIGNMENT is used in BPF_PROG_LOAD command, the
* verifier will allow any alignment whatsoever. On platforms
* with strict alignment requirements for loads ands stores (such
* as sparc and mips) the verifier validates that all loads and
* stores provably follow this requirement. This flag turns that
* checking and enforcement off.
*
* It is mostly used for testing when we want to validate the
* context and memory access aspects of the verifier, but because
* of an unaligned access the alignment check would trigger before
* the one we are interested in.
*/
#define BPF_F_ANY_ALIGNMENT (1U << 1)
/* BPF_F_TEST_RND_HI32 is used in BPF_PROG_LOAD command for testing purpose.
* Verifier does sub-register def/use analysis and identifies instructions whose
* def only matters for low 32-bit, high 32-bit is never referenced later
* through implicit zero extension. Therefore verifier notifies JIT back-ends
* that it is safe to ignore clearing high 32-bit for these instructions. This
* saves some back-ends a lot of code-gen. However such optimization is not
* necessary on some arches, for example x86_64, arm64 etc, whose JIT back-ends
* hence hasn't used verifier's analysis result. But, we really want to have a
* way to be able to verify the correctness of the described optimization on
* x86_64 on which testsuites are frequently exercised.
*
* So, this flag is introduced. Once it is set, verifier will randomize high
* 32-bit for those instructions who has been identified as safe to ignore them.
* Then, if verifier is not doing correct analysis, such randomization will
* regress tests to expose bugs.
*/
#define BPF_F_TEST_RND_HI32 (1U << 2)
/* The verifier internal test flag. Behavior is undefined */
#define BPF_F_TEST_STATE_FREQ (1U << 3)
/* If BPF_F_SLEEPABLE is used in BPF_PROG_LOAD command, the verifier will
* restrict map and helper usage for such programs. Sleepable BPF programs can
* only be attached to hooks where kernel execution context allows sleeping.
* Such programs are allowed to use helpers that may sleep like
* bpf_copy_from_user().
*/
#define BPF_F_SLEEPABLE (1U << 4)
/* If BPF_F_XDP_HAS_FRAGS is used in BPF_PROG_LOAD command, the loaded program
* fully support xdp frags.
*/
#define BPF_F_XDP_HAS_FRAGS (1U << 5)
/* If BPF_F_XDP_DEV_BOUND_ONLY is used in BPF_PROG_LOAD command, the loaded
* program becomes device-bound but can access XDP metadata.
*/
#define BPF_F_XDP_DEV_BOUND_ONLY (1U << 6)
/* The verifier internal test flag. Behavior is undefined */
#define BPF_F_TEST_REG_INVARIANTS (1U << 7)
/* link_create.kprobe_multi.flags used in LINK_CREATE command for
* BPF_TRACE_KPROBE_MULTI attach type to create return probe.
*/
enum {
BPF_F_KPROBE_MULTI_RETURN = (1U << 0)
};
/* link_create.uprobe_multi.flags used in LINK_CREATE command for
* BPF_TRACE_UPROBE_MULTI attach type to create return probe.
*/
enum {
BPF_F_UPROBE_MULTI_RETURN = (1U << 0)
};
/* link_create.netfilter.flags used in LINK_CREATE command for
* BPF_PROG_TYPE_NETFILTER to enable IP packet defragmentation.
*/
#define BPF_F_NETFILTER_IP_DEFRAG (1U << 0)
/* When BPF ldimm64's insn[0].src_reg != 0 then this can have
* the following extensions:
*
* insn[0].src_reg: BPF_PSEUDO_MAP_[FD|IDX]
* insn[0].imm: map fd or fd_idx
* insn[1].imm: 0
* insn[0].off: 0
* insn[1].off: 0
* ldimm64 rewrite: address of map
* verifier type: CONST_PTR_TO_MAP
*/
#define BPF_PSEUDO_MAP_FD 1
#define BPF_PSEUDO_MAP_IDX 5
/* insn[0].src_reg: BPF_PSEUDO_MAP_[IDX_]VALUE
* insn[0].imm: map fd or fd_idx
* insn[1].imm: offset into value
* insn[0].off: 0
* insn[1].off: 0
* ldimm64 rewrite: address of map[0]+offset
* verifier type: PTR_TO_MAP_VALUE
*/
#define BPF_PSEUDO_MAP_VALUE 2
#define BPF_PSEUDO_MAP_IDX_VALUE 6
/* insn[0].src_reg: BPF_PSEUDO_BTF_ID
* insn[0].imm: kernel btd id of VAR
* insn[1].imm: 0
* insn[0].off: 0
* insn[1].off: 0
* ldimm64 rewrite: address of the kernel variable
* verifier type: PTR_TO_BTF_ID or PTR_TO_MEM, depending on whether the var
* is struct/union.
*/
#define BPF_PSEUDO_BTF_ID 3
/* insn[0].src_reg: BPF_PSEUDO_FUNC
* insn[0].imm: insn offset to the func
* insn[1].imm: 0
* insn[0].off: 0
* insn[1].off: 0
* ldimm64 rewrite: address of the function
* verifier type: PTR_TO_FUNC.
*/
#define BPF_PSEUDO_FUNC 4
/* when bpf_call->src_reg == BPF_PSEUDO_CALL, bpf_call->imm == pc-relative
* offset to another bpf function
*/
#define BPF_PSEUDO_CALL 1
/* when bpf_call->src_reg == BPF_PSEUDO_KFUNC_CALL,
* bpf_call->imm == btf_id of a BTF_KIND_FUNC in the running kernel
*/
#define BPF_PSEUDO_KFUNC_CALL 2
/* flags for BPF_MAP_UPDATE_ELEM command */
enum {
BPF_ANY = 0, /* create new element or update existing */
BPF_NOEXIST = 1, /* create new element if it didn't exist */
BPF_EXIST = 2, /* update existing element */
BPF_F_LOCK = 4, /* spin_lock-ed map_lookup/map_update */
};
/* flags for BPF_MAP_CREATE command */
enum {
BPF_F_NO_PREALLOC = (1U << 0),
/* Instead of having one common LRU list in the
* BPF_MAP_TYPE_LRU_[PERCPU_]HASH map, use a percpu LRU list
* which can scale and perform better.
* Note, the LRU nodes (including free nodes) cannot be moved
* across different LRU lists.
*/
BPF_F_NO_COMMON_LRU = (1U << 1),
/* Specify numa node during map creation */
BPF_F_NUMA_NODE = (1U << 2),
/* Flags for accessing BPF object from syscall side. */
BPF_F_RDONLY = (1U << 3),
BPF_F_WRONLY = (1U << 4),
/* Flag for stack_map, store build_id+offset instead of pointer */
BPF_F_STACK_BUILD_ID = (1U << 5),
/* Zero-initialize hash function seed. This should only be used for testing. */
BPF_F_ZERO_SEED = (1U << 6),
/* Flags for accessing BPF object from program side. */
BPF_F_RDONLY_PROG = (1U << 7),
BPF_F_WRONLY_PROG = (1U << 8),
/* Clone map from listener for newly accepted socket */
BPF_F_CLONE = (1U << 9),
/* Enable memory-mapping BPF map */
BPF_F_MMAPABLE = (1U << 10),
/* Share perf_event among processes */
BPF_F_PRESERVE_ELEMS = (1U << 11),
/* Create a map that is suitable to be an inner map with dynamic max entries */
BPF_F_INNER_MAP = (1U << 12),
/* Create a map that will be registered/unregesitered by the backed bpf_link */
BPF_F_LINK = (1U << 13),
/* Get path from provided FD in BPF_OBJ_PIN/BPF_OBJ_GET commands */
BPF_F_PATH_FD = (1U << 14),
/* Flag for value_type_btf_obj_fd, the fd is available */
BPF_F_VTYPE_BTF_OBJ_FD = (1U << 15),
/* BPF token FD is passed in a corresponding command's token_fd field */
BPF_F_TOKEN_FD = (1U << 16),
};
/* Flags for BPF_PROG_QUERY. */
/* Query effective (directly attached + inherited from ancestor cgroups)
* programs that will be executed for events within a cgroup.
* attach_flags with this flag are always returned 0.
*/
#define BPF_F_QUERY_EFFECTIVE (1U << 0)
/* Flags for BPF_PROG_TEST_RUN */
/* If set, run the test on the cpu specified by bpf_attr.test.cpu */
#define BPF_F_TEST_RUN_ON_CPU (1U << 0)
/* If set, XDP frames will be transmitted after processing */
#define BPF_F_TEST_XDP_LIVE_FRAMES (1U << 1)
/* type for BPF_ENABLE_STATS */
enum bpf_stats_type {
/* enabled run_time_ns and run_cnt */
BPF_STATS_RUN_TIME = 0,
};
enum bpf_stack_build_id_status {
/* user space need an empty entry to identify end of a trace */
BPF_STACK_BUILD_ID_EMPTY = 0,
/* with valid build_id and offset */
BPF_STACK_BUILD_ID_VALID = 1,
/* couldn't get build_id, fallback to ip */
BPF_STACK_BUILD_ID_IP = 2,
};
#define BPF_BUILD_ID_SIZE 20
struct bpf_stack_build_id {
__s32 status;
unsigned char build_id[BPF_BUILD_ID_SIZE];
union {
__u64 offset;
__u64 ip;
};
};
#define BPF_OBJ_NAME_LEN 16U
union bpf_attr {
struct { /* anonymous struct used by BPF_MAP_CREATE command */
__u32 map_type; /* one of enum bpf_map_type */
__u32 key_size; /* size of key in bytes */
__u32 value_size; /* size of value in bytes */
__u32 max_entries; /* max number of entries in a map */
__u32 map_flags; /* BPF_MAP_CREATE related
* flags defined above.
*/
__u32 inner_map_fd; /* fd pointing to the inner map */
__u32 numa_node; /* numa node (effective only if
* BPF_F_NUMA_NODE is set).
*/
char map_name[BPF_OBJ_NAME_LEN];
__u32 map_ifindex; /* ifindex of netdev to create on */
__u32 btf_fd; /* fd pointing to a BTF type data */
__u32 btf_key_type_id; /* BTF type_id of the key */
__u32 btf_value_type_id; /* BTF type_id of the value */
__u32 btf_vmlinux_value_type_id;/* BTF type_id of a kernel-
* struct stored as the
* map value
*/
/* Any per-map-type extra fields
*
* BPF_MAP_TYPE_BLOOM_FILTER - the lowest 4 bits indicate the
* number of hash functions (if 0, the bloom filter will default
* to using 5 hash functions).
*/
__u64 map_extra;
__s32 value_type_btf_obj_fd; /* fd pointing to a BTF
* type data for
* btf_vmlinux_value_type_id.
*/
/* BPF token FD to use with BPF_MAP_CREATE operation.
* If provided, map_flags should have BPF_F_TOKEN_FD flag set.
*/
__s32 map_token_fd;
};
struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
__u32 map_fd;
__aligned_u64 key;
union {
__aligned_u64 value;
__aligned_u64 next_key;
};
__u64 flags;
};
struct { /* struct used by BPF_MAP_*_BATCH commands */
__aligned_u64 in_batch; /* start batch,
* NULL to start from beginning
*/
__aligned_u64 out_batch; /* output: next start batch */
__aligned_u64 keys;
__aligned_u64 values;
__u32 count; /* input/output:
* input: # of key/value
* elements
* output: # of filled elements
*/
__u32 map_fd;
__u64 elem_flags;
__u64 flags;
} batch;
struct { /* anonymous struct used by BPF_PROG_LOAD command */
__u32 prog_type; /* one of enum bpf_prog_type */
__u32 insn_cnt;
__aligned_u64 insns;
__aligned_u64 license;
__u32 log_level; /* verbosity level of verifier */
__u32 log_size; /* size of user buffer */
__aligned_u64 log_buf; /* user supplied buffer */
__u32 kern_version; /* not used */
__u32 prog_flags;
char prog_name[BPF_OBJ_NAME_LEN];
__u32 prog_ifindex; /* ifindex of netdev to prep for */
/* For some prog types expected attach type must be known at
* load time to verify attach type specific parts of prog
* (context accesses, allowed helpers, etc).
*/
__u32 expected_attach_type;
__u32 prog_btf_fd; /* fd pointing to BTF type data */
__u32 func_info_rec_size; /* userspace bpf_func_info size */
__aligned_u64 func_info; /* func info */
__u32 func_info_cnt; /* number of bpf_func_info records */
__u32 line_info_rec_size; /* userspace bpf_line_info size */
__aligned_u64 line_info; /* line info */
__u32 line_info_cnt; /* number of bpf_line_info records */
__u32 attach_btf_id; /* in-kernel BTF type id to attach to */
union {
/* valid prog_fd to attach to bpf prog */
__u32 attach_prog_fd;
/* or valid module BTF object fd or 0 to attach to vmlinux */
__u32 attach_btf_obj_fd;
};
__u32 core_relo_cnt; /* number of bpf_core_relo */
__aligned_u64 fd_array; /* array of FDs */
__aligned_u64 core_relos;
__u32 core_relo_rec_size; /* sizeof(struct bpf_core_relo) */
/* output: actual total log contents size (including termintaing zero).
* It could be both larger than original log_size (if log was
* truncated), or smaller (if log buffer wasn't filled completely).
*/
__u32 log_true_size;
/* BPF token FD to use with BPF_PROG_LOAD operation.
* If provided, prog_flags should have BPF_F_TOKEN_FD flag set.
*/
__s32 prog_token_fd;
};
struct { /* anonymous struct used by BPF_OBJ_* commands */
__aligned_u64 pathname;
__u32 bpf_fd;
__u32 file_flags;
/* Same as dirfd in openat() syscall; see openat(2)
* manpage for details of path FD and pathname semantics;
* path_fd should accompanied by BPF_F_PATH_FD flag set in
* file_flags field, otherwise it should be set to zero;
* if BPF_F_PATH_FD flag is not set, AT_FDCWD is assumed.
*/
__s32 path_fd;
};
struct { /* anonymous struct used by BPF_PROG_ATTACH/DETACH commands */
union {
__u32 target_fd; /* target object to attach to or ... */
__u32 target_ifindex; /* target ifindex */
};
__u32 attach_bpf_fd;
__u32 attach_type;
__u32 attach_flags;
__u32 replace_bpf_fd;
union {
__u32 relative_fd;
__u32 relative_id;
};
__u64 expected_revision;
};
struct { /* anonymous struct used by BPF_PROG_TEST_RUN command */
__u32 prog_fd;
__u32 retval;
__u32 data_size_in; /* input: len of data_in */
__u32 data_size_out; /* input/output: len of data_out
* returns ENOSPC if data_out
* is too small.
*/
__aligned_u64 data_in;
__aligned_u64 data_out;
__u32 repeat;
__u32 duration;
__u32 ctx_size_in; /* input: len of ctx_in */
__u32 ctx_size_out; /* input/output: len of ctx_out
* returns ENOSPC if ctx_out
* is too small.
*/
__aligned_u64 ctx_in;
__aligned_u64 ctx_out;
__u32 flags;
__u32 cpu;
__u32 batch_size;
} test;
struct { /* anonymous struct used by BPF_*_GET_*_ID */
union {
__u32 start_id;
__u32 prog_id;
__u32 map_id;
__u32 btf_id;
__u32 link_id;
};
__u32 next_id;
__u32 open_flags;
};
struct { /* anonymous struct used by BPF_OBJ_GET_INFO_BY_FD */
__u32 bpf_fd;
__u32 info_len;
__aligned_u64 info;
} info;
struct { /* anonymous struct used by BPF_PROG_QUERY command */
union {
__u32 target_fd; /* target object to query or ... */
__u32 target_ifindex; /* target ifindex */
};
__u32 attach_type;
__u32 query_flags;
__u32 attach_flags;
__aligned_u64 prog_ids;
union {
__u32 prog_cnt;
__u32 count;
};
__u32 :32;
/* output: per-program attach_flags.
* not allowed to be set during effective query.
*/
__aligned_u64 prog_attach_flags;
__aligned_u64 link_ids;
__aligned_u64 link_attach_flags;
__u64 revision;
} query;
struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
__u64 name;
__u32 prog_fd;
} raw_tracepoint;
struct { /* anonymous struct for BPF_BTF_LOAD */
__aligned_u64 btf;
__aligned_u64 btf_log_buf;
__u32 btf_size;
__u32 btf_log_size;
__u32 btf_log_level;
/* output: actual total log contents size (including termintaing zero).
* It could be both larger than original log_size (if log was
* truncated), or smaller (if log buffer wasn't filled completely).
*/
__u32 btf_log_true_size;
__u32 btf_flags;
/* BPF token FD to use with BPF_BTF_LOAD operation.
* If provided, btf_flags should have BPF_F_TOKEN_FD flag set.
*/
__s32 btf_token_fd;
};
struct {
__u32 pid; /* input: pid */
__u32 fd; /* input: fd */
__u32 flags; /* input: flags */
__u32 buf_len; /* input/output: buf len */
__aligned_u64 buf; /* input/output:
* tp_name for tracepoint
* symbol for kprobe
* filename for uprobe
*/
__u32 prog_id; /* output: prod_id */
__u32 fd_type; /* output: BPF_FD_TYPE_* */
__u64 probe_offset; /* output: probe_offset */
__u64 probe_addr; /* output: probe_addr */
} task_fd_query;
struct { /* struct used by BPF_LINK_CREATE command */
union {
__u32 prog_fd; /* eBPF program to attach */
__u32 map_fd; /* struct_ops to attach */
};
union {
__u32 target_fd; /* target object to attach to or ... */
__u32 target_ifindex; /* target ifindex */
};
__u32 attach_type; /* attach type */
__u32 flags; /* extra flags */
union {
__u32 target_btf_id; /* btf_id of target to attach to */
struct {
__aligned_u64 iter_info; /* extra bpf_iter_link_info */
__u32 iter_info_len; /* iter_info length */
};
struct {
/* black box user-provided value passed through
* to BPF program at the execution time and
* accessible through bpf_get_attach_cookie() BPF helper
*/
__u64 bpf_cookie;
} perf_event;
struct {
__u32 flags;
__u32 cnt;
__aligned_u64 syms;
__aligned_u64 addrs;
__aligned_u64 cookies;
} kprobe_multi;
struct {
/* this is overlaid with the target_btf_id above. */
__u32 target_btf_id;
/* black box user-provided value passed through
* to BPF program at the execution time and
* accessible through bpf_get_attach_cookie() BPF helper
*/
__u64 cookie;
} tracing;
struct {
__u32 pf;
__u32 hooknum;
__s32 priority;
__u32 flags;
} netfilter;
struct {
union {
__u32 relative_fd;
__u32 relative_id;
};
__u64 expected_revision;
} tcx;
struct {
__aligned_u64 path;
__aligned_u64 offsets;
__aligned_u64 ref_ctr_offsets;
__aligned_u64 cookies;
__u32 cnt;
__u32 flags;
__u32 pid;
} uprobe_multi;
struct {
union {
__u32 relative_fd;
__u32 relative_id;
};
__u64 expected_revision;
} netkit;
};
} link_create;
struct { /* struct used by BPF_LINK_UPDATE command */
__u32 link_fd; /* link fd */
union {
/* new program fd to update link with */
__u32 new_prog_fd;
/* new struct_ops map fd to update link with */
__u32 new_map_fd;
};
__u32 flags; /* extra flags */
union {
/* expected link's program fd; is specified only if
* BPF_F_REPLACE flag is set in flags.
*/
__u32 old_prog_fd;
/* expected link's map fd; is specified only
* if BPF_F_REPLACE flag is set.
*/
__u32 old_map_fd;
};
} link_update;
struct {
__u32 link_fd;
} link_detach;
struct { /* struct used by BPF_ENABLE_STATS command */
__u32 type;
} enable_stats;
struct { /* struct used by BPF_ITER_CREATE command */
__u32 link_fd;
__u32 flags;
} iter_create;
struct { /* struct used by BPF_PROG_BIND_MAP command */
__u32 prog_fd;
__u32 map_fd;
__u32 flags; /* extra flags */
} prog_bind_map;
struct { /* struct used by BPF_TOKEN_CREATE command */
__u32 flags;
__u32 bpffs_fd;
} token_create;
} __attribute__((aligned(8)));
/* The description below is an attempt at providing documentation to eBPF
* developers about the multiple available eBPF helper functions. It can be
* parsed and used to produce a manual page. The workflow is the following,
* and requires the rst2man utility:
*
* $ ./scripts/bpf_doc.py \
* --filename include/uapi/linux/bpf.h > /tmp/bpf-helpers.rst
* $ rst2man /tmp/bpf-helpers.rst > /tmp/bpf-helpers.7
* $ man /tmp/bpf-helpers.7
*
* Note that in order to produce this external documentation, some RST
* formatting is used in the descriptions to get "bold" and "italics" in
* manual pages. Also note that the few trailing white spaces are
* intentional, removing them would break paragraphs for rst2man.
*
* Start of BPF helper function descriptions:
*
* void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
* Description
* Perform a lookup in *map* for an entry associated to *key*.
* Return
* Map value associated to *key*, or **NULL** if no entry was
* found.
*
* long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
* Description
* Add or update the value of the entry associated to *key* in
* *map* with *value*. *flags* is one of:
*
* **BPF_NOEXIST**
* The entry for *key* must not exist in the map.
* **BPF_EXIST**
* The entry for *key* must already exist in the map.
* **BPF_ANY**
* No condition on the existence of the entry for *key*.
*
* Flag value **BPF_NOEXIST** cannot be used for maps of types
* **BPF_MAP_TYPE_ARRAY** or **BPF_MAP_TYPE_PERCPU_ARRAY** (all
* elements always exist), the helper would return an error.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_map_delete_elem(struct bpf_map *map, const void *key)
* Description
* Delete entry with *key* from *map*.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_probe_read(void *dst, u32 size, const void *unsafe_ptr)
* Description
* For tracing programs, safely attempt to read *size* bytes from
* kernel space address *unsafe_ptr* and store the data in *dst*.
*
* Generally, use **bpf_probe_read_user**\ () or
* **bpf_probe_read_kernel**\ () instead.
* Return
* 0 on success, or a negative error in case of failure.
*
* u64 bpf_ktime_get_ns(void)
* Description
* Return the time elapsed since system boot, in nanoseconds.
* Does not include time the system was suspended.
* See: **clock_gettime**\ (**CLOCK_MONOTONIC**)
* Return
* Current *ktime*.
*
* long bpf_trace_printk(const char *fmt, u32 fmt_size, ...)
* Description
* This helper is a "printk()-like" facility for debugging. It
* prints a message defined by format *fmt* (of size *fmt_size*)
* to file *\/sys/kernel/tracing/trace* from TraceFS, if
* available. It can take up to three additional **u64**
* arguments (as an eBPF helpers, the total number of arguments is
* limited to five).
*
* Each time the helper is called, it appends a line to the trace.
* Lines are discarded while *\/sys/kernel/tracing/trace* is
* open, use *\/sys/kernel/tracing/trace_pipe* to avoid this.
* The format of the trace is customizable, and the exact output
* one will get depends on the options set in
* *\/sys/kernel/tracing/trace_options* (see also the
* *README* file under the same directory). However, it usually
* defaults to something like:
*
* ::
*
* telnet-470 [001] .N.. 419421.045894: 0x00000001: <formatted msg>
*
* In the above:
*
* * ``telnet`` is the name of the current task.
* * ``470`` is the PID of the current task.
* * ``001`` is the CPU number on which the task is
* running.
* * In ``.N..``, each character refers to a set of
* options (whether irqs are enabled, scheduling
* options, whether hard/softirqs are running, level of
* preempt_disabled respectively). **N** means that
* **TIF_NEED_RESCHED** and **PREEMPT_NEED_RESCHED**
* are set.
* * ``419421.045894`` is a timestamp.
* * ``0x00000001`` is a fake value used by BPF for the
* instruction pointer register.
* * ``<formatted msg>`` is the message formatted with
* *fmt*.
*
* The conversion specifiers supported by *fmt* are similar, but
* more limited than for printk(). They are **%d**, **%i**,
* **%u**, **%x**, **%ld**, **%li**, **%lu**, **%lx**, **%lld**,
* **%lli**, **%llu**, **%llx**, **%p**, **%s**. No modifier (size
* of field, padding with zeroes, etc.) is available, and the
* helper will return **-EINVAL** (but print nothing) if it
* encounters an unknown specifier.
*
* Also, note that **bpf_trace_printk**\ () is slow, and should
* only be used for debugging purposes. For this reason, a notice
* block (spanning several lines) is printed to kernel logs and
* states that the helper should not be used "for production use"
* the first time this helper is used (or more precisely, when
* **trace_printk**\ () buffers are allocated). For passing values
* to user space, perf events should be preferred.
* Return
* The number of bytes written to the buffer, or a negative error
* in case of failure.
*
* u32 bpf_get_prandom_u32(void)
* Description
* Get a pseudo-random number.
*
* From a security point of view, this helper uses its own
* pseudo-random internal state, and cannot be used to infer the
* seed of other random functions in the kernel. However, it is
* essential to note that the generator used by the helper is not
* cryptographically secure.
* Return
* A random 32-bit unsigned value.
*
* u32 bpf_get_smp_processor_id(void)
* Description
* Get the SMP (symmetric multiprocessing) processor id. Note that
* all programs run with migration disabled, which means that the
* SMP processor id is stable during all the execution of the
* program.
* Return
* The SMP id of the processor running the program.
*
* long bpf_skb_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len, u64 flags)
* Description
* Store *len* bytes from address *from* into the packet
* associated to *skb*, at *offset*. *flags* are a combination of
* **BPF_F_RECOMPUTE_CSUM** (automatically recompute the
* checksum for the packet after storing the bytes) and
* **BPF_F_INVALIDATE_HASH** (set *skb*\ **->hash**, *skb*\
* **->swhash** and *skb*\ **->l4hash** to 0).
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_l3_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 size)
* Description
* Recompute the layer 3 (e.g. IP) checksum for the packet
* associated to *skb*. Computation is incremental, so the helper
* must know the former value of the header field that was
* modified (*from*), the new value of this field (*to*), and the
* number of bytes (2 or 4) for this field, stored in *size*.
* Alternatively, it is possible to store the difference between
* the previous and the new values of the header field in *to*, by
* setting *from* and *size* to 0. For both methods, *offset*
* indicates the location of the IP checksum within the packet.
*
* This helper works in combination with **bpf_csum_diff**\ (),
* which does not update the checksum in-place, but offers more
* flexibility and can handle sizes larger than 2 or 4 for the
* checksum to update.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_l4_csum_replace(struct sk_buff *skb, u32 offset, u64 from, u64 to, u64 flags)
* Description
* Recompute the layer 4 (e.g. TCP, UDP or ICMP) checksum for the
* packet associated to *skb*. Computation is incremental, so the
* helper must know the former value of the header field that was
* modified (*from*), the new value of this field (*to*), and the
* number of bytes (2 or 4) for this field, stored on the lowest
* four bits of *flags*. Alternatively, it is possible to store
* the difference between the previous and the new values of the
* header field in *to*, by setting *from* and the four lowest
* bits of *flags* to 0. For both methods, *offset* indicates the
* location of the IP checksum within the packet. In addition to
* the size of the field, *flags* can be added (bitwise OR) actual
* flags. With **BPF_F_MARK_MANGLED_0**, a null checksum is left
* untouched (unless **BPF_F_MARK_ENFORCE** is added as well), and
* for updates resulting in a null checksum the value is set to
* **CSUM_MANGLED_0** instead. Flag **BPF_F_PSEUDO_HDR** indicates
* the checksum is to be computed against a pseudo-header.
*
* This helper works in combination with **bpf_csum_diff**\ (),
* which does not update the checksum in-place, but offers more
* flexibility and can handle sizes larger than 2 or 4 for the
* checksum to update.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_tail_call(void *ctx, struct bpf_map *prog_array_map, u32 index)
* Description
* This special helper is used to trigger a "tail call", or in
* other words, to jump into another eBPF program. The same stack
* frame is used (but values on stack and in registers for the
* caller are not accessible to the callee). This mechanism allows
* for program chaining, either for raising the maximum number of
* available eBPF instructions, or to execute given programs in
* conditional blocks. For security reasons, there is an upper
* limit to the number of successive tail calls that can be
* performed.
*
* Upon call of this helper, the program attempts to jump into a
* program referenced at index *index* in *prog_array_map*, a
* special map of type **BPF_MAP_TYPE_PROG_ARRAY**, and passes
* *ctx*, a pointer to the context.
*
* If the call succeeds, the kernel immediately runs the first
* instruction of the new program. This is not a function call,
* and it never returns to the previous program. If the call
* fails, then the helper has no effect, and the caller continues
* to run its subsequent instructions. A call can fail if the
* destination program for the jump does not exist (i.e. *index*
* is superior to the number of entries in *prog_array_map*), or
* if the maximum number of tail calls has been reached for this
* chain of programs. This limit is defined in the kernel by the
* macro **MAX_TAIL_CALL_CNT** (not accessible to user space),
* which is currently set to 33.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_clone_redirect(struct sk_buff *skb, u32 ifindex, u64 flags)
* Description
* Clone and redirect the packet associated to *skb* to another
* net device of index *ifindex*. Both ingress and egress
* interfaces can be used for redirection. The **BPF_F_INGRESS**
* value in *flags* is used to make the distinction (ingress path
* is selected if the flag is present, egress path otherwise).
* This is the only flag supported for now.
*
* In comparison with **bpf_redirect**\ () helper,
* **bpf_clone_redirect**\ () has the associated cost of
* duplicating the packet buffer, but this can be executed out of
* the eBPF program. Conversely, **bpf_redirect**\ () is more
* efficient, but it is handled through an action code where the
* redirection happens only after the eBPF program has returned.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure. Positive
* error indicates a potential drop or congestion in the target
* device. The particular positive error codes are not defined.
*
* u64 bpf_get_current_pid_tgid(void)
* Description
* Get the current pid and tgid.
* Return
* A 64-bit integer containing the current tgid and pid, and
* created as such:
* *current_task*\ **->tgid << 32 \|**
* *current_task*\ **->pid**.
*
* u64 bpf_get_current_uid_gid(void)
* Description
* Get the current uid and gid.
* Return
* A 64-bit integer containing the current GID and UID, and
* created as such: *current_gid* **<< 32 \|** *current_uid*.
*
* long bpf_get_current_comm(void *buf, u32 size_of_buf)
* Description
* Copy the **comm** attribute of the current task into *buf* of
* *size_of_buf*. The **comm** attribute contains the name of
* the executable (excluding the path) for the current task. The
* *size_of_buf* must be strictly positive. On success, the
* helper makes sure that the *buf* is NUL-terminated. On failure,
* it is filled with zeroes.
* Return
* 0 on success, or a negative error in case of failure.
*
* u32 bpf_get_cgroup_classid(struct sk_buff *skb)
* Description
* Retrieve the classid for the current task, i.e. for the net_cls
* cgroup to which *skb* belongs.
*
* This helper can be used on TC egress path, but not on ingress.
*
* The net_cls cgroup provides an interface to tag network packets
* based on a user-provided identifier for all traffic coming from
* the tasks belonging to the related cgroup. See also the related
* kernel documentation, available from the Linux sources in file
* *Documentation/admin-guide/cgroup-v1/net_cls.rst*.
*
* The Linux kernel has two versions for cgroups: there are
* cgroups v1 and cgroups v2. Both are available to users, who can
* use a mixture of them, but note that the net_cls cgroup is for
* cgroup v1 only. This makes it incompatible with BPF programs
* run on cgroups, which is a cgroup-v2-only feature (a socket can
* only hold data for one version of cgroups at a time).
*
* This helper is only available is the kernel was compiled with
* the **CONFIG_CGROUP_NET_CLASSID** configuration option set to
* "**y**" or to "**m**".
* Return
* The classid, or 0 for the default unconfigured classid.
*
* long bpf_skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci)
* Description
* Push a *vlan_tci* (VLAN tag control information) of protocol
* *vlan_proto* to the packet associated to *skb*, then update
* the checksum. Note that if *vlan_proto* is different from
* **ETH_P_8021Q** and **ETH_P_8021AD**, it is considered to
* be **ETH_P_8021Q**.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_skb_vlan_pop(struct sk_buff *skb)
* Description
* Pop a VLAN header from the packet associated to *skb*.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_skb_get_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
* Description
* Get tunnel metadata. This helper takes a pointer *key* to an
* empty **struct bpf_tunnel_key** of **size**, that will be
* filled with tunnel metadata for the packet associated to *skb*.
* The *flags* can be set to **BPF_F_TUNINFO_IPV6**, which
* indicates that the tunnel is based on IPv6 protocol instead of
* IPv4.
*
* The **struct bpf_tunnel_key** is an object that generalizes the
* principal parameters used by various tunneling protocols into a
* single struct. This way, it can be used to easily make a
* decision based on the contents of the encapsulation header,
* "summarized" in this struct. In particular, it holds the IP
* address of the remote end (IPv4 or IPv6, depending on the case)
* in *key*\ **->remote_ipv4** or *key*\ **->remote_ipv6**. Also,
* this struct exposes the *key*\ **->tunnel_id**, which is
* generally mapped to a VNI (Virtual Network Identifier), making
* it programmable together with the **bpf_skb_set_tunnel_key**\
* () helper.
*
* Let's imagine that the following code is part of a program
* attached to the TC ingress interface, on one end of a GRE
* tunnel, and is supposed to filter out all messages coming from
* remote ends with IPv4 address other than 10.0.0.1:
*
* ::
*
* int ret;
* struct bpf_tunnel_key key = {};
*
* ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0);
* if (ret < 0)
* return TC_ACT_SHOT; // drop packet
*
* if (key.remote_ipv4 != 0x0a000001)
* return TC_ACT_SHOT; // drop packet
*
* return TC_ACT_OK; // accept packet
*
* This interface can also be used with all encapsulation devices
* that can operate in "collect metadata" mode: instead of having
* one network device per specific configuration, the "collect
* metadata" mode only requires a single device where the
* configuration can be extracted from this helper.
*
* This can be used together with various tunnels such as VXLan,
* Geneve, GRE or IP in IP (IPIP).
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_skb_set_tunnel_key(struct sk_buff *skb, struct bpf_tunnel_key *key, u32 size, u64 flags)
* Description
* Populate tunnel metadata for packet associated to *skb.* The
* tunnel metadata is set to the contents of *key*, of *size*. The
* *flags* can be set to a combination of the following values:
*
* **BPF_F_TUNINFO_IPV6**
* Indicate that the tunnel is based on IPv6 protocol
* instead of IPv4.
* **BPF_F_ZERO_CSUM_TX**
* For IPv4 packets, add a flag to tunnel metadata
* indicating that checksum computation should be skipped
* and checksum set to zeroes.
* **BPF_F_DONT_FRAGMENT**
* Add a flag to tunnel metadata indicating that the
* packet should not be fragmented.
* **BPF_F_SEQ_NUMBER**
* Add a flag to tunnel metadata indicating that a
* sequence number should be added to tunnel header before
* sending the packet. This flag was added for GRE
* encapsulation, but might be used with other protocols
* as well in the future.
* **BPF_F_NO_TUNNEL_KEY**
* Add a flag to tunnel metadata indicating that no tunnel
* key should be set in the resulting tunnel header.
*
* Here is a typical usage on the transmit path:
*
* ::
*
* struct bpf_tunnel_key key;
* populate key ...
* bpf_skb_set_tunnel_key(skb, &key, sizeof(key), 0);
* bpf_clone_redirect(skb, vxlan_dev_ifindex, 0);
*
* See also the description of the **bpf_skb_get_tunnel_key**\ ()
* helper for additional information.
* Return
* 0 on success, or a negative error in case of failure.
*
* u64 bpf_perf_event_read(struct bpf_map *map, u64 flags)
* Description
* Read the value of a perf event counter. This helper relies on a
* *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of
* the perf event counter is selected when *map* is updated with
* perf event file descriptors. The *map* is an array whose size
* is the number of available CPUs, and each cell contains a value
* relative to one CPU. The value to retrieve is indicated by
* *flags*, that contains the index of the CPU to look up, masked
* with **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
* **BPF_F_CURRENT_CPU** to indicate that the value for the
* current CPU should be retrieved.
*
* Note that before Linux 4.13, only hardware perf event can be
* retrieved.
*
* Also, be aware that the newer helper
* **bpf_perf_event_read_value**\ () is recommended over
* **bpf_perf_event_read**\ () in general. The latter has some ABI
* quirks where error and counter value are used as a return code
* (which is wrong to do since ranges may overlap). This issue is
* fixed with **bpf_perf_event_read_value**\ (), which at the same
* time provides more features over the **bpf_perf_event_read**\
* () interface. Please refer to the description of
* **bpf_perf_event_read_value**\ () for details.
* Return
* The value of the perf event counter read from the map, or a
* negative error code in case of failure.
*
* long bpf_redirect(u32 ifindex, u64 flags)
* Description
* Redirect the packet to another net device of index *ifindex*.
* This helper is somewhat similar to **bpf_clone_redirect**\
* (), except that the packet is not cloned, which provides
* increased performance.
*
* Except for XDP, both ingress and egress interfaces can be used
* for redirection. The **BPF_F_INGRESS** value in *flags* is used
* to make the distinction (ingress path is selected if the flag
* is present, egress path otherwise). Currently, XDP only
* supports redirection to the egress interface, and accepts no
* flag at all.
*
* The same effect can also be attained with the more generic
* **bpf_redirect_map**\ (), which uses a BPF map to store the
* redirect target instead of providing it directly to the helper.
* Return
* For XDP, the helper returns **XDP_REDIRECT** on success or
* **XDP_ABORTED** on error. For other program types, the values
* are **TC_ACT_REDIRECT** on success or **TC_ACT_SHOT** on
* error.
*
* u32 bpf_get_route_realm(struct sk_buff *skb)
* Description
* Retrieve the realm or the route, that is to say the
* **tclassid** field of the destination for the *skb*. The
* identifier retrieved is a user-provided tag, similar to the
* one used with the net_cls cgroup (see description for
* **bpf_get_cgroup_classid**\ () helper), but here this tag is
* held by a route (a destination entry), not by a task.
*
* Retrieving this identifier works with the clsact TC egress hook
* (see also **tc-bpf(8)**), or alternatively on conventional
* classful egress qdiscs, but not on TC ingress path. In case of
* clsact TC egress hook, this has the advantage that, internally,
* the destination entry has not been dropped yet in the transmit
* path. Therefore, the destination entry does not need to be
* artificially held via **netif_keep_dst**\ () for a classful
* qdisc until the *skb* is freed.
*
* This helper is available only if the kernel was compiled with
* **CONFIG_IP_ROUTE_CLASSID** configuration option.
* Return
* The realm of the route for the packet associated to *skb*, or 0
* if none was found.
*
* long bpf_perf_event_output(void *ctx, struct bpf_map *map, u64 flags, void *data, u64 size)
* Description
* Write raw *data* blob into a special BPF perf event held by
* *map* of type **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. This perf
* event must have the following attributes: **PERF_SAMPLE_RAW**
* as **sample_type**, **PERF_TYPE_SOFTWARE** as **type**, and
* **PERF_COUNT_SW_BPF_OUTPUT** as **config**.
*
* The *flags* are used to indicate the index in *map* for which
* the value must be put, masked with **BPF_F_INDEX_MASK**.
* Alternatively, *flags* can be set to **BPF_F_CURRENT_CPU**
* to indicate that the index of the current CPU core should be
* used.
*
* The value to write, of *size*, is passed through eBPF stack and
* pointed by *data*.
*
* The context of the program *ctx* needs also be passed to the
* helper.
*
* On user space, a program willing to read the values needs to
* call **perf_event_open**\ () on the perf event (either for
* one or for all CPUs) and to store the file descriptor into the
* *map*. This must be done before the eBPF program can send data
* into it. An example is available in file
* *samples/bpf/trace_output_user.c* in the Linux kernel source
* tree (the eBPF program counterpart is in
* *samples/bpf/trace_output_kern.c*).
*
* **bpf_perf_event_output**\ () achieves better performance
* than **bpf_trace_printk**\ () for sharing data with user
* space, and is much better suitable for streaming data from eBPF
* programs.
*
* Note that this helper is not restricted to tracing use cases
* and can be used with programs attached to TC or XDP as well,
* where it allows for passing data to user space listeners. Data
* can be:
*
* * Only custom structs,
* * Only the packet payload, or
* * A combination of both.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_skb_load_bytes(const void *skb, u32 offset, void *to, u32 len)
* Description
* This helper was provided as an easy way to load data from a
* packet. It can be used to load *len* bytes from *offset* from
* the packet associated to *skb*, into the buffer pointed by
* *to*.
*
* Since Linux 4.7, usage of this helper has mostly been replaced
* by "direct packet access", enabling packet data to be
* manipulated with *skb*\ **->data** and *skb*\ **->data_end**
* pointing respectively to the first byte of packet data and to
* the byte after the last byte of packet data. However, it
* remains useful if one wishes to read large quantities of data
* at once from a packet into the eBPF stack.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_get_stackid(void *ctx, struct bpf_map *map, u64 flags)
* Description
* Walk a user or a kernel stack and return its id. To achieve
* this, the helper needs *ctx*, which is a pointer to the context
* on which the tracing program is executed, and a pointer to a
* *map* of type **BPF_MAP_TYPE_STACK_TRACE**.
*
* The last argument, *flags*, holds the number of stack frames to
* skip (from 0 to 255), masked with
* **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
* a combination of the following flags:
*
* **BPF_F_USER_STACK**
* Collect a user space stack instead of a kernel stack.
* **BPF_F_FAST_STACK_CMP**
* Compare stacks by hash only.
* **BPF_F_REUSE_STACKID**
* If two different stacks hash into the same *stackid*,
* discard the old one.
*
* The stack id retrieved is a 32 bit long integer handle which
* can be further combined with other data (including other stack
* ids) and used as a key into maps. This can be useful for
* generating a variety of graphs (such as flame graphs or off-cpu
* graphs).
*
* For walking a stack, this helper is an improvement over
* **bpf_probe_read**\ (), which can be used with unrolled loops
* but is not efficient and consumes a lot of eBPF instructions.
* Instead, **bpf_get_stackid**\ () can collect up to
* **PERF_MAX_STACK_DEPTH** both kernel and user frames. Note that
* this limit can be controlled with the **sysctl** program, and
* that it should be manually increased in order to profile long
* user stacks (such as stacks for Java programs). To do so, use:
*
* ::
*
* # sysctl kernel.perf_event_max_stack=<new value>
* Return
* The positive or null stack id on success, or a negative error
* in case of failure.
*
* s64 bpf_csum_diff(__be32 *from, u32 from_size, __be32 *to, u32 to_size, __wsum seed)
* Description
* Compute a checksum difference, from the raw buffer pointed by
* *from*, of length *from_size* (that must be a multiple of 4),
* towards the raw buffer pointed by *to*, of size *to_size*
* (same remark). An optional *seed* can be added to the value
* (this can be cascaded, the seed may come from a previous call
* to the helper).
*
* This is flexible enough to be used in several ways:
*
* * With *from_size* == 0, *to_size* > 0 and *seed* set to
* checksum, it can be used when pushing new data.
* * With *from_size* > 0, *to_size* == 0 and *seed* set to
* checksum, it can be used when removing data from a packet.
* * With *from_size* > 0, *to_size* > 0 and *seed* set to 0, it
* can be used to compute a diff. Note that *from_size* and
* *to_size* do not need to be equal.
*
* This helper can be used in combination with
* **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\ (), to
* which one can feed in the difference computed with
* **bpf_csum_diff**\ ().
* Return
* The checksum result, or a negative error code in case of
* failure.
*
* long bpf_skb_get_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
* Description
* Retrieve tunnel options metadata for the packet associated to
* *skb*, and store the raw tunnel option data to the buffer *opt*
* of *size*.
*
* This helper can be used with encapsulation devices that can
* operate in "collect metadata" mode (please refer to the related
* note in the description of **bpf_skb_get_tunnel_key**\ () for
* more details). A particular example where this can be used is
* in combination with the Geneve encapsulation protocol, where it
* allows for pushing (with **bpf_skb_get_tunnel_opt**\ () helper)
* and retrieving arbitrary TLVs (Type-Length-Value headers) from
* the eBPF program. This allows for full customization of these
* headers.
* Return
* The size of the option data retrieved.
*
* long bpf_skb_set_tunnel_opt(struct sk_buff *skb, void *opt, u32 size)
* Description
* Set tunnel options metadata for the packet associated to *skb*
* to the option data contained in the raw buffer *opt* of *size*.
*
* See also the description of the **bpf_skb_get_tunnel_opt**\ ()
* helper for additional information.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_skb_change_proto(struct sk_buff *skb, __be16 proto, u64 flags)
* Description
* Change the protocol of the *skb* to *proto*. Currently
* supported are transition from IPv4 to IPv6, and from IPv6 to
* IPv4. The helper takes care of the groundwork for the
* transition, including resizing the socket buffer. The eBPF
* program is expected to fill the new headers, if any, via
* **skb_store_bytes**\ () and to recompute the checksums with
* **bpf_l3_csum_replace**\ () and **bpf_l4_csum_replace**\
* (). The main case for this helper is to perform NAT64
* operations out of an eBPF program.
*
* Internally, the GSO type is marked as dodgy so that headers are
* checked and segments are recalculated by the GSO/GRO engine.
* The size for GSO target is adapted as well.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_skb_change_type(struct sk_buff *skb, u32 type)
* Description
* Change the packet type for the packet associated to *skb*. This
* comes down to setting *skb*\ **->pkt_type** to *type*, except
* the eBPF program does not have a write access to *skb*\
* **->pkt_type** beside this helper. Using a helper here allows
* for graceful handling of errors.
*
* The major use case is to change incoming *skb*s to
* **PACKET_HOST** in a programmatic way instead of having to
* recirculate via **redirect**\ (..., **BPF_F_INGRESS**), for
* example.
*
* Note that *type* only allows certain values. At this time, they
* are:
*
* **PACKET_HOST**
* Packet is for us.
* **PACKET_BROADCAST**
* Send packet to all.
* **PACKET_MULTICAST**
* Send packet to group.
* **PACKET_OTHERHOST**
* Send packet to someone else.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_skb_under_cgroup(struct sk_buff *skb, struct bpf_map *map, u32 index)
* Description
* Check whether *skb* is a descendant of the cgroup2 held by
* *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
* Return
* The return value depends on the result of the test, and can be:
*
* * 0, if the *skb* failed the cgroup2 descendant test.
* * 1, if the *skb* succeeded the cgroup2 descendant test.
* * A negative error code, if an error occurred.
*
* u32 bpf_get_hash_recalc(struct sk_buff *skb)
* Description
* Retrieve the hash of the packet, *skb*\ **->hash**. If it is
* not set, in particular if the hash was cleared due to mangling,
* recompute this hash. Later accesses to the hash can be done
* directly with *skb*\ **->hash**.
*
* Calling **bpf_set_hash_invalid**\ (), changing a packet
* prototype with **bpf_skb_change_proto**\ (), or calling
* **bpf_skb_store_bytes**\ () with the
* **BPF_F_INVALIDATE_HASH** are actions susceptible to clear
* the hash and to trigger a new computation for the next call to
* **bpf_get_hash_recalc**\ ().
* Return
* The 32-bit hash.
*
* u64 bpf_get_current_task(void)
* Description
* Get the current task.
* Return
* A pointer to the current task struct.
*
* long bpf_probe_write_user(void *dst, const void *src, u32 len)
* Description
* Attempt in a safe way to write *len* bytes from the buffer
* *src* to *dst* in memory. It only works for threads that are in
* user context, and *dst* must be a valid user space address.
*
* This helper should not be used to implement any kind of
* security mechanism because of TOC-TOU attacks, but rather to
* debug, divert, and manipulate execution of semi-cooperative
* processes.
*
* Keep in mind that this feature is meant for experiments, and it
* has a risk of crashing the system and running programs.
* Therefore, when an eBPF program using this helper is attached,
* a warning including PID and process name is printed to kernel
* logs.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_current_task_under_cgroup(struct bpf_map *map, u32 index)
* Description
* Check whether the probe is being run is the context of a given
* subset of the cgroup2 hierarchy. The cgroup2 to test is held by
* *map* of type **BPF_MAP_TYPE_CGROUP_ARRAY**, at *index*.
* Return
* The return value depends on the result of the test, and can be:
*
* * 1, if current task belongs to the cgroup2.
* * 0, if current task does not belong to the cgroup2.
* * A negative error code, if an error occurred.
*
* long bpf_skb_change_tail(struct sk_buff *skb, u32 len, u64 flags)
* Description
* Resize (trim or grow) the packet associated to *skb* to the
* new *len*. The *flags* are reserved for future usage, and must
* be left at zero.
*
* The basic idea is that the helper performs the needed work to
* change the size of the packet, then the eBPF program rewrites
* the rest via helpers like **bpf_skb_store_bytes**\ (),
* **bpf_l3_csum_replace**\ (), **bpf_l3_csum_replace**\ ()
* and others. This helper is a slow path utility intended for
* replies with control messages. And because it is targeted for
* slow path, the helper itself can afford to be slow: it
* implicitly linearizes, unclones and drops offloads from the
* *skb*.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_skb_pull_data(struct sk_buff *skb, u32 len)
* Description
* Pull in non-linear data in case the *skb* is non-linear and not
* all of *len* are part of the linear section. Make *len* bytes
* from *skb* readable and writable. If a zero value is passed for
* *len*, then all bytes in the linear part of *skb* will be made
* readable and writable.
*
* This helper is only needed for reading and writing with direct
* packet access.
*
* For direct packet access, testing that offsets to access
* are within packet boundaries (test on *skb*\ **->data_end**) is
* susceptible to fail if offsets are invalid, or if the requested
* data is in non-linear parts of the *skb*. On failure the
* program can just bail out, or in the case of a non-linear
* buffer, use a helper to make the data available. The
* **bpf_skb_load_bytes**\ () helper is a first solution to access
* the data. Another one consists in using **bpf_skb_pull_data**
* to pull in once the non-linear parts, then retesting and
* eventually access the data.
*
* At the same time, this also makes sure the *skb* is uncloned,
* which is a necessary condition for direct write. As this needs
* to be an invariant for the write part only, the verifier
* detects writes and adds a prologue that is calling
* **bpf_skb_pull_data()** to effectively unclone the *skb* from
* the very beginning in case it is indeed cloned.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* s64 bpf_csum_update(struct sk_buff *skb, __wsum csum)
* Description
* Add the checksum *csum* into *skb*\ **->csum** in case the
* driver has supplied a checksum for the entire packet into that
* field. Return an error otherwise. This helper is intended to be
* used in combination with **bpf_csum_diff**\ (), in particular
* when the checksum needs to be updated after data has been
* written into the packet through direct packet access.
* Return
* The checksum on success, or a negative error code in case of
* failure.
*
* void bpf_set_hash_invalid(struct sk_buff *skb)
* Description
* Invalidate the current *skb*\ **->hash**. It can be used after
* mangling on headers through direct packet access, in order to
* indicate that the hash is outdated and to trigger a
* recalculation the next time the kernel tries to access this
* hash or when the **bpf_get_hash_recalc**\ () helper is called.
* Return
* void.
*
* long bpf_get_numa_node_id(void)
* Description
* Return the id of the current NUMA node. The primary use case
* for this helper is the selection of sockets for the local NUMA
* node, when the program is attached to sockets using the
* **SO_ATTACH_REUSEPORT_EBPF** option (see also **socket(7)**),
* but the helper is also available to other eBPF program types,
* similarly to **bpf_get_smp_processor_id**\ ().
* Return
* The id of current NUMA node.
*
* long bpf_skb_change_head(struct sk_buff *skb, u32 len, u64 flags)
* Description
* Grows headroom of packet associated to *skb* and adjusts the
* offset of the MAC header accordingly, adding *len* bytes of
* space. It automatically extends and reallocates memory as
* required.
*
* This helper can be used on a layer 3 *skb* to push a MAC header
* for redirection into a layer 2 device.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_xdp_adjust_head(struct xdp_buff *xdp_md, int delta)
* Description
* Adjust (move) *xdp_md*\ **->data** by *delta* bytes. Note that
* it is possible to use a negative value for *delta*. This helper
* can be used to prepare the packet for pushing or popping
* headers.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_probe_read_str(void *dst, u32 size, const void *unsafe_ptr)
* Description
* Copy a NUL terminated string from an unsafe kernel address
* *unsafe_ptr* to *dst*. See **bpf_probe_read_kernel_str**\ () for
* more details.
*
* Generally, use **bpf_probe_read_user_str**\ () or
* **bpf_probe_read_kernel_str**\ () instead.
* Return
* On success, the strictly positive length of the string,
* including the trailing NUL character. On error, a negative
* value.
*
* u64 bpf_get_socket_cookie(struct sk_buff *skb)
* Description
* If the **struct sk_buff** pointed by *skb* has a known socket,
* retrieve the cookie (generated by the kernel) of this socket.
* If no cookie has been set yet, generate a new cookie. Once
* generated, the socket cookie remains stable for the life of the
* socket. This helper can be useful for monitoring per socket
* networking traffic statistics as it provides a global socket
* identifier that can be assumed unique.
* Return
* A 8-byte long unique number on success, or 0 if the socket
* field is missing inside *skb*.
*
* u64 bpf_get_socket_cookie(struct bpf_sock_addr *ctx)
* Description
* Equivalent to bpf_get_socket_cookie() helper that accepts
* *skb*, but gets socket from **struct bpf_sock_addr** context.
* Return
* A 8-byte long unique number.
*
* u64 bpf_get_socket_cookie(struct bpf_sock_ops *ctx)
* Description
* Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
* *skb*, but gets socket from **struct bpf_sock_ops** context.
* Return
* A 8-byte long unique number.
*
* u64 bpf_get_socket_cookie(struct sock *sk)
* Description
* Equivalent to **bpf_get_socket_cookie**\ () helper that accepts
* *sk*, but gets socket from a BTF **struct sock**. This helper
* also works for sleepable programs.
* Return
* A 8-byte long unique number or 0 if *sk* is NULL.
*
* u32 bpf_get_socket_uid(struct sk_buff *skb)
* Description
* Get the owner UID of the socked associated to *skb*.
* Return
* The owner UID of the socket associated to *skb*. If the socket
* is **NULL**, or if it is not a full socket (i.e. if it is a
* time-wait or a request socket instead), **overflowuid** value
* is returned (note that **overflowuid** might also be the actual
* UID value for the socket).
*
* long bpf_set_hash(struct sk_buff *skb, u32 hash)
* Description
* Set the full hash for *skb* (set the field *skb*\ **->hash**)
* to value *hash*.
* Return
* 0
*
* long bpf_setsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
* Description
* Emulate a call to **setsockopt()** on the socket associated to
* *bpf_socket*, which must be a full socket. The *level* at
* which the option resides and the name *optname* of the option
* must be specified, see **setsockopt(2)** for more information.
* The option value of length *optlen* is pointed by *optval*.
*
* *bpf_socket* should be one of the following:
*
* * **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
* * **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**,
* **BPF_CGROUP_INET6_CONNECT** and **BPF_CGROUP_UNIX_CONNECT**.
*
* This helper actually implements a subset of **setsockopt()**.
* It supports the following *level*\ s:
*
* * **SOL_SOCKET**, which supports the following *optname*\ s:
* **SO_RCVBUF**, **SO_SNDBUF**, **SO_MAX_PACING_RATE**,
* **SO_PRIORITY**, **SO_RCVLOWAT**, **SO_MARK**,
* **SO_BINDTODEVICE**, **SO_KEEPALIVE**, **SO_REUSEADDR**,
* **SO_REUSEPORT**, **SO_BINDTOIFINDEX**, **SO_TXREHASH**.
* * **IPPROTO_TCP**, which supports the following *optname*\ s:
* **TCP_CONGESTION**, **TCP_BPF_IW**,
* **TCP_BPF_SNDCWND_CLAMP**, **TCP_SAVE_SYN**,
* **TCP_KEEPIDLE**, **TCP_KEEPINTVL**, **TCP_KEEPCNT**,
* **TCP_SYNCNT**, **TCP_USER_TIMEOUT**, **TCP_NOTSENT_LOWAT**,
* **TCP_NODELAY**, **TCP_MAXSEG**, **TCP_WINDOW_CLAMP**,
* **TCP_THIN_LINEAR_TIMEOUTS**, **TCP_BPF_DELACK_MAX**,
* **TCP_BPF_RTO_MIN**.
* * **IPPROTO_IP**, which supports *optname* **IP_TOS**.
* * **IPPROTO_IPV6**, which supports the following *optname*\ s:
* **IPV6_TCLASS**, **IPV6_AUTOFLOWLABEL**.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_skb_adjust_room(struct sk_buff *skb, s32 len_diff, u32 mode, u64 flags)
* Description
* Grow or shrink the room for data in the packet associated to
* *skb* by *len_diff*, and according to the selected *mode*.
*
* By default, the helper will reset any offloaded checksum
* indicator of the skb to CHECKSUM_NONE. This can be avoided
* by the following flag:
*
* * **BPF_F_ADJ_ROOM_NO_CSUM_RESET**: Do not reset offloaded
* checksum data of the skb to CHECKSUM_NONE.
*
* There are two supported modes at this time:
*
* * **BPF_ADJ_ROOM_MAC**: Adjust room at the mac layer
* (room space is added or removed between the layer 2 and
* layer 3 headers).
*
* * **BPF_ADJ_ROOM_NET**: Adjust room at the network layer
* (room space is added or removed between the layer 3 and
* layer 4 headers).
*
* The following flags are supported at this time:
*
* * **BPF_F_ADJ_ROOM_FIXED_GSO**: Do not adjust gso_size.
* Adjusting mss in this way is not allowed for datagrams.
*
* * **BPF_F_ADJ_ROOM_ENCAP_L3_IPV4**,
* **BPF_F_ADJ_ROOM_ENCAP_L3_IPV6**:
* Any new space is reserved to hold a tunnel header.
* Configure skb offsets and other fields accordingly.
*
* * **BPF_F_ADJ_ROOM_ENCAP_L4_GRE**,
* **BPF_F_ADJ_ROOM_ENCAP_L4_UDP**:
* Use with ENCAP_L3 flags to further specify the tunnel type.
*
* * **BPF_F_ADJ_ROOM_ENCAP_L2**\ (*len*):
* Use with ENCAP_L3/L4 flags to further specify the tunnel
* type; *len* is the length of the inner MAC header.
*
* * **BPF_F_ADJ_ROOM_ENCAP_L2_ETH**:
* Use with BPF_F_ADJ_ROOM_ENCAP_L2 flag to further specify the
* L2 type as Ethernet.
*
* * **BPF_F_ADJ_ROOM_DECAP_L3_IPV4**,
* **BPF_F_ADJ_ROOM_DECAP_L3_IPV6**:
* Indicate the new IP header version after decapsulating the outer
* IP header. Used when the inner and outer IP versions are different.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_redirect_map(struct bpf_map *map, u64 key, u64 flags)
* Description
* Redirect the packet to the endpoint referenced by *map* at
* index *key*. Depending on its type, this *map* can contain
* references to net devices (for forwarding packets through other
* ports), or to CPUs (for redirecting XDP frames to another CPU;
* but this is only implemented for native XDP (with driver
* support) as of this writing).
*
* The lower two bits of *flags* are used as the return code if
* the map lookup fails. This is so that the return value can be
* one of the XDP program return codes up to **XDP_TX**, as chosen
* by the caller. The higher bits of *flags* can be set to
* BPF_F_BROADCAST or BPF_F_EXCLUDE_INGRESS as defined below.
*
* With BPF_F_BROADCAST the packet will be broadcasted to all the
* interfaces in the map, with BPF_F_EXCLUDE_INGRESS the ingress
* interface will be excluded when do broadcasting.
*
* See also **bpf_redirect**\ (), which only supports redirecting
* to an ifindex, but doesn't require a map to do so.
* Return
* **XDP_REDIRECT** on success, or the value of the two lower bits
* of the *flags* argument on error.
*
* long bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key, u64 flags)
* Description
* Redirect the packet to the socket referenced by *map* (of type
* **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
* egress interfaces can be used for redirection. The
* **BPF_F_INGRESS** value in *flags* is used to make the
* distinction (ingress path is selected if the flag is present,
* egress path otherwise). This is the only flag supported for now.
* Return
* **SK_PASS** on success, or **SK_DROP** on error.
*
* long bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
* Description
* Add an entry to, or update a *map* referencing sockets. The
* *skops* is used as a new value for the entry associated to
* *key*. *flags* is one of:
*
* **BPF_NOEXIST**
* The entry for *key* must not exist in the map.
* **BPF_EXIST**
* The entry for *key* must already exist in the map.
* **BPF_ANY**
* No condition on the existence of the entry for *key*.
*
* If the *map* has eBPF programs (parser and verdict), those will
* be inherited by the socket being added. If the socket is
* already attached to eBPF programs, this results in an error.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_xdp_adjust_meta(struct xdp_buff *xdp_md, int delta)
* Description
* Adjust the address pointed by *xdp_md*\ **->data_meta** by
* *delta* (which can be positive or negative). Note that this
* operation modifies the address stored in *xdp_md*\ **->data**,
* so the latter must be loaded only after the helper has been
* called.
*
* The use of *xdp_md*\ **->data_meta** is optional and programs
* are not required to use it. The rationale is that when the
* packet is processed with XDP (e.g. as DoS filter), it is
* possible to push further meta data along with it before passing
* to the stack, and to give the guarantee that an ingress eBPF
* program attached as a TC classifier on the same device can pick
* this up for further post-processing. Since TC works with socket
* buffers, it remains possible to set from XDP the **mark** or
* **priority** pointers, or other pointers for the socket buffer.
* Having this scratch space generic and programmable allows for
* more flexibility as the user is free to store whatever meta
* data they need.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_perf_event_read_value(struct bpf_map *map, u64 flags, struct bpf_perf_event_value *buf, u32 buf_size)
* Description
* Read the value of a perf event counter, and store it into *buf*
* of size *buf_size*. This helper relies on a *map* of type
* **BPF_MAP_TYPE_PERF_EVENT_ARRAY**. The nature of the perf event
* counter is selected when *map* is updated with perf event file
* descriptors. The *map* is an array whose size is the number of
* available CPUs, and each cell contains a value relative to one
* CPU. The value to retrieve is indicated by *flags*, that
* contains the index of the CPU to look up, masked with
* **BPF_F_INDEX_MASK**. Alternatively, *flags* can be set to
* **BPF_F_CURRENT_CPU** to indicate that the value for the
* current CPU should be retrieved.
*
* This helper behaves in a way close to
* **bpf_perf_event_read**\ () helper, save that instead of
* just returning the value observed, it fills the *buf*
* structure. This allows for additional data to be retrieved: in
* particular, the enabled and running times (in *buf*\
* **->enabled** and *buf*\ **->running**, respectively) are
* copied. In general, **bpf_perf_event_read_value**\ () is
* recommended over **bpf_perf_event_read**\ (), which has some
* ABI issues and provides fewer functionalities.
*
* These values are interesting, because hardware PMU (Performance
* Monitoring Unit) counters are limited resources. When there are
* more PMU based perf events opened than available counters,
* kernel will multiplex these events so each event gets certain
* percentage (but not all) of the PMU time. In case that
* multiplexing happens, the number of samples or counter value
* will not reflect the case compared to when no multiplexing
* occurs. This makes comparison between different runs difficult.
* Typically, the counter value should be normalized before
* comparing to other experiments. The usual normalization is done
* as follows.
*
* ::
*
* normalized_counter = counter * t_enabled / t_running
*
* Where t_enabled is the time enabled for event and t_running is
* the time running for event since last normalization. The
* enabled and running times are accumulated since the perf event
* open. To achieve scaling factor between two invocations of an
* eBPF program, users can use CPU id as the key (which is
* typical for perf array usage model) to remember the previous
* value and do the calculation inside the eBPF program.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_perf_prog_read_value(struct bpf_perf_event_data *ctx, struct bpf_perf_event_value *buf, u32 buf_size)
* Description
* For an eBPF program attached to a perf event, retrieve the
* value of the event counter associated to *ctx* and store it in
* the structure pointed by *buf* and of size *buf_size*. Enabled
* and running times are also stored in the structure (see
* description of helper **bpf_perf_event_read_value**\ () for
* more details).
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_getsockopt(void *bpf_socket, int level, int optname, void *optval, int optlen)
* Description
* Emulate a call to **getsockopt()** on the socket associated to
* *bpf_socket*, which must be a full socket. The *level* at
* which the option resides and the name *optname* of the option
* must be specified, see **getsockopt(2)** for more information.
* The retrieved value is stored in the structure pointed by
* *opval* and of length *optlen*.
*
* *bpf_socket* should be one of the following:
*
* * **struct bpf_sock_ops** for **BPF_PROG_TYPE_SOCK_OPS**.
* * **struct bpf_sock_addr** for **BPF_CGROUP_INET4_CONNECT**,
* **BPF_CGROUP_INET6_CONNECT** and **BPF_CGROUP_UNIX_CONNECT**.
*
* This helper actually implements a subset of **getsockopt()**.
* It supports the same set of *optname*\ s that is supported by
* the **bpf_setsockopt**\ () helper. The exceptions are
* **TCP_BPF_*** is **bpf_setsockopt**\ () only and
* **TCP_SAVED_SYN** is **bpf_getsockopt**\ () only.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_override_return(struct pt_regs *regs, u64 rc)
* Description
* Used for error injection, this helper uses kprobes to override
* the return value of the probed function, and to set it to *rc*.
* The first argument is the context *regs* on which the kprobe
* works.
*
* This helper works by setting the PC (program counter)
* to an override function which is run in place of the original
* probed function. This means the probed function is not run at
* all. The replacement function just returns with the required
* value.
*
* This helper has security implications, and thus is subject to
* restrictions. It is only available if the kernel was compiled
* with the **CONFIG_BPF_KPROBE_OVERRIDE** configuration
* option, and in this case it only works on functions tagged with
* **ALLOW_ERROR_INJECTION** in the kernel code.
*
* Also, the helper is only available for the architectures having
* the CONFIG_FUNCTION_ERROR_INJECTION option. As of this writing,
* x86 architecture is the only one to support this feature.
* Return
* 0
*
* long bpf_sock_ops_cb_flags_set(struct bpf_sock_ops *bpf_sock, int argval)
* Description
* Attempt to set the value of the **bpf_sock_ops_cb_flags** field
* for the full TCP socket associated to *bpf_sock_ops* to
* *argval*.
*
* The primary use of this field is to determine if there should
* be calls to eBPF programs of type
* **BPF_PROG_TYPE_SOCK_OPS** at various points in the TCP
* code. A program of the same type can change its value, per
* connection and as necessary, when the connection is
* established. This field is directly accessible for reading, but
* this helper must be used for updates in order to return an
* error if an eBPF program tries to set a callback that is not
* supported in the current kernel.
*
* *argval* is a flag array which can combine these flags:
*
* * **BPF_SOCK_OPS_RTO_CB_FLAG** (retransmission time out)
* * **BPF_SOCK_OPS_RETRANS_CB_FLAG** (retransmission)
* * **BPF_SOCK_OPS_STATE_CB_FLAG** (TCP state change)
* * **BPF_SOCK_OPS_RTT_CB_FLAG** (every RTT)
*
* Therefore, this function can be used to clear a callback flag by
* setting the appropriate bit to zero. e.g. to disable the RTO
* callback:
*
* **bpf_sock_ops_cb_flags_set(bpf_sock,**
* **bpf_sock->bpf_sock_ops_cb_flags & ~BPF_SOCK_OPS_RTO_CB_FLAG)**
*
* Here are some examples of where one could call such eBPF
* program:
*
* * When RTO fires.
* * When a packet is retransmitted.
* * When the connection terminates.
* * When a packet is sent.
* * When a packet is received.
* Return
* Code **-EINVAL** if the socket is not a full TCP socket;
* otherwise, a positive number containing the bits that could not
* be set is returned (which comes down to 0 if all bits were set
* as required).
*
* long bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
* Description
* This helper is used in programs implementing policies at the
* socket level. If the message *msg* is allowed to pass (i.e. if
* the verdict eBPF program returns **SK_PASS**), redirect it to
* the socket referenced by *map* (of type
* **BPF_MAP_TYPE_SOCKMAP**) at index *key*. Both ingress and
* egress interfaces can be used for redirection. The
* **BPF_F_INGRESS** value in *flags* is used to make the
* distinction (ingress path is selected if the flag is present,
* egress path otherwise). This is the only flag supported for now.
* Return
* **SK_PASS** on success, or **SK_DROP** on error.
*
* long bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
* Description
* For socket policies, apply the verdict of the eBPF program to
* the next *bytes* (number of bytes) of message *msg*.
*
* For example, this helper can be used in the following cases:
*
* * A single **sendmsg**\ () or **sendfile**\ () system call
* contains multiple logical messages that the eBPF program is
* supposed to read and for which it should apply a verdict.
* * An eBPF program only cares to read the first *bytes* of a
* *msg*. If the message has a large payload, then setting up
* and calling the eBPF program repeatedly for all bytes, even
* though the verdict is already known, would create unnecessary
* overhead.
*
* When called from within an eBPF program, the helper sets a
* counter internal to the BPF infrastructure, that is used to
* apply the last verdict to the next *bytes*. If *bytes* is
* smaller than the current data being processed from a
* **sendmsg**\ () or **sendfile**\ () system call, the first
* *bytes* will be sent and the eBPF program will be re-run with
* the pointer for start of data pointing to byte number *bytes*
* **+ 1**. If *bytes* is larger than the current data being
* processed, then the eBPF verdict will be applied to multiple
* **sendmsg**\ () or **sendfile**\ () calls until *bytes* are
* consumed.
*
* Note that if a socket closes with the internal counter holding
* a non-zero value, this is not a problem because data is not
* being buffered for *bytes* and is sent as it is received.
* Return
* 0
*
* long bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
* Description
* For socket policies, prevent the execution of the verdict eBPF
* program for message *msg* until *bytes* (byte number) have been
* accumulated.
*
* This can be used when one needs a specific number of bytes
* before a verdict can be assigned, even if the data spans
* multiple **sendmsg**\ () or **sendfile**\ () calls. The extreme
* case would be a user calling **sendmsg**\ () repeatedly with
* 1-byte long message segments. Obviously, this is bad for
* performance, but it is still valid. If the eBPF program needs
* *bytes* bytes to validate a header, this helper can be used to
* prevent the eBPF program to be called again until *bytes* have
* been accumulated.
* Return
* 0
*
* long bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
* Description
* For socket policies, pull in non-linear data from user space
* for *msg* and set pointers *msg*\ **->data** and *msg*\
* **->data_end** to *start* and *end* bytes offsets into *msg*,
* respectively.
*
* If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
* *msg* it can only parse data that the (**data**, **data_end**)
* pointers have already consumed. For **sendmsg**\ () hooks this
* is likely the first scatterlist element. But for calls relying
* on the **sendpage** handler (e.g. **sendfile**\ ()) this will
* be the range (**0**, **0**) because the data is shared with
* user space and by default the objective is to avoid allowing
* user space to modify data while (or after) eBPF verdict is
* being decided. This helper can be used to pull in data and to
* set the start and end pointer to given values. Data will be
* copied if necessary (i.e. if data was not linear and if start
* and end pointers do not point to the same chunk).
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_bind(struct bpf_sock_addr *ctx, struct sockaddr *addr, int addr_len)
* Description
* Bind the socket associated to *ctx* to the address pointed by
* *addr*, of length *addr_len*. This allows for making outgoing
* connection from the desired IP address, which can be useful for
* example when all processes inside a cgroup should use one
* single IP address on a host that has multiple IP configured.
*
* This helper works for IPv4 and IPv6, TCP and UDP sockets. The
* domain (*addr*\ **->sa_family**) must be **AF_INET** (or
* **AF_INET6**). It's advised to pass zero port (**sin_port**
* or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like
* behavior and lets the kernel efficiently pick up an unused
* port as long as 4-tuple is unique. Passing non-zero port might
* lead to degraded performance.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_xdp_adjust_tail(struct xdp_buff *xdp_md, int delta)
* Description
* Adjust (move) *xdp_md*\ **->data_end** by *delta* bytes. It is
* possible to both shrink and grow the packet tail.
* Shrink done via *delta* being a negative integer.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_skb_get_xfrm_state(struct sk_buff *skb, u32 index, struct bpf_xfrm_state *xfrm_state, u32 size, u64 flags)
* Description
* Retrieve the XFRM state (IP transform framework, see also
* **ip-xfrm(8)**) at *index* in XFRM "security path" for *skb*.
*
* The retrieved value is stored in the **struct bpf_xfrm_state**
* pointed by *xfrm_state* and of length *size*.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
*
* This helper is available only if the kernel was compiled with
* **CONFIG_XFRM** configuration option.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_get_stack(void *ctx, void *buf, u32 size, u64 flags)
* Description
* Return a user or a kernel stack in bpf program provided buffer.
* To achieve this, the helper needs *ctx*, which is a pointer
* to the context on which the tracing program is executed.
* To store the stacktrace, the bpf program provides *buf* with
* a nonnegative *size*.
*
* The last argument, *flags*, holds the number of stack frames to
* skip (from 0 to 255), masked with
* **BPF_F_SKIP_FIELD_MASK**. The next bits can be used to set
* the following flags:
*
* **BPF_F_USER_STACK**
* Collect a user space stack instead of a kernel stack.
* **BPF_F_USER_BUILD_ID**
* Collect (build_id, file_offset) instead of ips for user
* stack, only valid if **BPF_F_USER_STACK** is also
* specified.
*
* *file_offset* is an offset relative to the beginning
* of the executable or shared object file backing the vma
* which the *ip* falls in. It is *not* an offset relative
* to that object's base address. Accordingly, it must be
* adjusted by adding (sh_addr - sh_offset), where
* sh_{addr,offset} correspond to the executable section
* containing *file_offset* in the object, for comparisons
* to symbols' st_value to be valid.
*
* **bpf_get_stack**\ () can collect up to
* **PERF_MAX_STACK_DEPTH** both kernel and user frames, subject
* to sufficient large buffer size. Note that
* this limit can be controlled with the **sysctl** program, and
* that it should be manually increased in order to profile long
* user stacks (such as stacks for Java programs). To do so, use:
*
* ::
*
* # sysctl kernel.perf_event_max_stack=<new value>
* Return
* The non-negative copied *buf* length equal to or less than
* *size* on success, or a negative error in case of failure.
*
* long bpf_skb_load_bytes_relative(const void *skb, u32 offset, void *to, u32 len, u32 start_header)
* Description
* This helper is similar to **bpf_skb_load_bytes**\ () in that
* it provides an easy way to load *len* bytes from *offset*
* from the packet associated to *skb*, into the buffer pointed
* by *to*. The difference to **bpf_skb_load_bytes**\ () is that
* a fifth argument *start_header* exists in order to select a
* base offset to start from. *start_header* can be one of:
*
* **BPF_HDR_START_MAC**
* Base offset to load data from is *skb*'s mac header.
* **BPF_HDR_START_NET**
* Base offset to load data from is *skb*'s network header.
*
* In general, "direct packet access" is the preferred method to
* access packet data, however, this helper is in particular useful
* in socket filters where *skb*\ **->data** does not always point
* to the start of the mac header and where "direct packet access"
* is not available.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_fib_lookup(void *ctx, struct bpf_fib_lookup *params, int plen, u32 flags)
* Description
* Do FIB lookup in kernel tables using parameters in *params*.
* If lookup is successful and result shows packet is to be
* forwarded, the neighbor tables are searched for the nexthop.
* If successful (ie., FIB lookup shows forwarding and nexthop
* is resolved), the nexthop address is returned in ipv4_dst
* or ipv6_dst based on family, smac is set to mac address of
* egress device, dmac is set to nexthop mac address, rt_metric
* is set to metric from route (IPv4/IPv6 only), and ifindex
* is set to the device index of the nexthop from the FIB lookup.
*
* *plen* argument is the size of the passed in struct.
* *flags* argument can be a combination of one or more of the
* following values:
*
* **BPF_FIB_LOOKUP_DIRECT**
* Do a direct table lookup vs full lookup using FIB
* rules.
* **BPF_FIB_LOOKUP_TBID**
* Used with BPF_FIB_LOOKUP_DIRECT.
* Use the routing table ID present in *params*->tbid
* for the fib lookup.
* **BPF_FIB_LOOKUP_OUTPUT**
* Perform lookup from an egress perspective (default is
* ingress).
* **BPF_FIB_LOOKUP_SKIP_NEIGH**
* Skip the neighbour table lookup. *params*->dmac
* and *params*->smac will not be set as output. A common
* use case is to call **bpf_redirect_neigh**\ () after
* doing **bpf_fib_lookup**\ ().
* **BPF_FIB_LOOKUP_SRC**
* Derive and set source IP addr in *params*->ipv{4,6}_src
* for the nexthop. If the src addr cannot be derived,
* **BPF_FIB_LKUP_RET_NO_SRC_ADDR** is returned. In this
* case, *params*->dmac and *params*->smac are not set either.
*
* *ctx* is either **struct xdp_md** for XDP programs or
* **struct sk_buff** tc cls_act programs.
* Return
* * < 0 if any input argument is invalid
* * 0 on success (packet is forwarded, nexthop neighbor exists)
* * > 0 one of **BPF_FIB_LKUP_RET_** codes explaining why the
* packet is not forwarded or needs assist from full stack
*
* If lookup fails with BPF_FIB_LKUP_RET_FRAG_NEEDED, then the MTU
* was exceeded and output params->mtu_result contains the MTU.
*
* long bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
* Description
* Add an entry to, or update a sockhash *map* referencing sockets.
* The *skops* is used as a new value for the entry associated to
* *key*. *flags* is one of:
*
* **BPF_NOEXIST**
* The entry for *key* must not exist in the map.
* **BPF_EXIST**
* The entry for *key* must already exist in the map.
* **BPF_ANY**
* No condition on the existence of the entry for *key*.
*
* If the *map* has eBPF programs (parser and verdict), those will
* be inherited by the socket being added. If the socket is
* already attached to eBPF programs, this results in an error.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
* Description
* This helper is used in programs implementing policies at the
* socket level. If the message *msg* is allowed to pass (i.e. if
* the verdict eBPF program returns **SK_PASS**), redirect it to
* the socket referenced by *map* (of type
* **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
* egress interfaces can be used for redirection. The
* **BPF_F_INGRESS** value in *flags* is used to make the
* distinction (ingress path is selected if the flag is present,
* egress path otherwise). This is the only flag supported for now.
* Return
* **SK_PASS** on success, or **SK_DROP** on error.
*
* long bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
* Description
* This helper is used in programs implementing policies at the
* skb socket level. If the sk_buff *skb* is allowed to pass (i.e.
* if the verdict eBPF program returns **SK_PASS**), redirect it
* to the socket referenced by *map* (of type
* **BPF_MAP_TYPE_SOCKHASH**) using hash *key*. Both ingress and
* egress interfaces can be used for redirection. The
* **BPF_F_INGRESS** value in *flags* is used to make the
* distinction (ingress path is selected if the flag is present,
* egress otherwise). This is the only flag supported for now.
* Return
* **SK_PASS** on success, or **SK_DROP** on error.
*
* long bpf_lwt_push_encap(struct sk_buff *skb, u32 type, void *hdr, u32 len)
* Description
* Encapsulate the packet associated to *skb* within a Layer 3
* protocol header. This header is provided in the buffer at
* address *hdr*, with *len* its size in bytes. *type* indicates
* the protocol of the header and can be one of:
*
* **BPF_LWT_ENCAP_SEG6**
* IPv6 encapsulation with Segment Routing Header
* (**struct ipv6_sr_hdr**). *hdr* only contains the SRH,
* the IPv6 header is computed by the kernel.
* **BPF_LWT_ENCAP_SEG6_INLINE**
* Only works if *skb* contains an IPv6 packet. Insert a
* Segment Routing Header (**struct ipv6_sr_hdr**) inside
* the IPv6 header.
* **BPF_LWT_ENCAP_IP**
* IP encapsulation (GRE/GUE/IPIP/etc). The outer header
* must be IPv4 or IPv6, followed by zero or more
* additional headers, up to **LWT_BPF_MAX_HEADROOM**
* total bytes in all prepended headers. Please note that
* if **skb_is_gso**\ (*skb*) is true, no more than two
* headers can be prepended, and the inner header, if
* present, should be either GRE or UDP/GUE.
*
* **BPF_LWT_ENCAP_SEG6**\ \* types can be called by BPF programs
* of type **BPF_PROG_TYPE_LWT_IN**; **BPF_LWT_ENCAP_IP** type can
* be called by bpf programs of types **BPF_PROG_TYPE_LWT_IN** and
* **BPF_PROG_TYPE_LWT_XMIT**.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_lwt_seg6_store_bytes(struct sk_buff *skb, u32 offset, const void *from, u32 len)
* Description
* Store *len* bytes from address *from* into the packet
* associated to *skb*, at *offset*. Only the flags, tag and TLVs
* inside the outermost IPv6 Segment Routing Header can be
* modified through this helper.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_lwt_seg6_adjust_srh(struct sk_buff *skb, u32 offset, s32 delta)
* Description
* Adjust the size allocated to TLVs in the outermost IPv6
* Segment Routing Header contained in the packet associated to
* *skb*, at position *offset* by *delta* bytes. Only offsets
* after the segments are accepted. *delta* can be as well
* positive (growing) as negative (shrinking).
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_lwt_seg6_action(struct sk_buff *skb, u32 action, void *param, u32 param_len)
* Description
* Apply an IPv6 Segment Routing action of type *action* to the
* packet associated to *skb*. Each action takes a parameter
* contained at address *param*, and of length *param_len* bytes.
* *action* can be one of:
*
* **SEG6_LOCAL_ACTION_END_X**
* End.X action: Endpoint with Layer-3 cross-connect.
* Type of *param*: **struct in6_addr**.
* **SEG6_LOCAL_ACTION_END_T**
* End.T action: Endpoint with specific IPv6 table lookup.
* Type of *param*: **int**.
* **SEG6_LOCAL_ACTION_END_B6**
* End.B6 action: Endpoint bound to an SRv6 policy.
* Type of *param*: **struct ipv6_sr_hdr**.
* **SEG6_LOCAL_ACTION_END_B6_ENCAP**
* End.B6.Encap action: Endpoint bound to an SRv6
* encapsulation policy.
* Type of *param*: **struct ipv6_sr_hdr**.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
* previously done by the verifier are invalidated and must be
* performed again, if the helper is used in combination with
* direct packet access.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_rc_repeat(void *ctx)
* Description
* This helper is used in programs implementing IR decoding, to
* report a successfully decoded repeat key message. This delays
* the generation of a key up event for previously generated
* key down event.
*
* Some IR protocols like NEC have a special IR message for
* repeating last button, for when a button is held down.
*
* The *ctx* should point to the lirc sample as passed into
* the program.
*
* This helper is only available is the kernel was compiled with
* the **CONFIG_BPF_LIRC_MODE2** configuration option set to
* "**y**".
* Return
* 0
*
* long bpf_rc_keydown(void *ctx, u32 protocol, u64 scancode, u32 toggle)
* Description
* This helper is used in programs implementing IR decoding, to
* report a successfully decoded key press with *scancode*,
* *toggle* value in the given *protocol*. The scancode will be
* translated to a keycode using the rc keymap, and reported as
* an input key down event. After a period a key up event is
* generated. This period can be extended by calling either
* **bpf_rc_keydown**\ () again with the same values, or calling
* **bpf_rc_repeat**\ ().
*
* Some protocols include a toggle bit, in case the button was
* released and pressed again between consecutive scancodes.
*
* The *ctx* should point to the lirc sample as passed into
* the program.
*
* The *protocol* is the decoded protocol number (see
* **enum rc_proto** for some predefined values).
*
* This helper is only available is the kernel was compiled with
* the **CONFIG_BPF_LIRC_MODE2** configuration option set to
* "**y**".
* Return
* 0
*
* u64 bpf_skb_cgroup_id(struct sk_buff *skb)
* Description
* Return the cgroup v2 id of the socket associated with the *skb*.
* This is roughly similar to the **bpf_get_cgroup_classid**\ ()
* helper for cgroup v1 by providing a tag resp. identifier that
* can be matched on or used for map lookups e.g. to implement
* policy. The cgroup v2 id of a given path in the hierarchy is
* exposed in user space through the f_handle API in order to get
* to the same 64-bit id.
*
* This helper can be used on TC egress path, but not on ingress,
* and is available only if the kernel was compiled with the
* **CONFIG_SOCK_CGROUP_DATA** configuration option.
* Return
* The id is returned or 0 in case the id could not be retrieved.
*
* u64 bpf_get_current_cgroup_id(void)
* Description
* Get the current cgroup id based on the cgroup within which
* the current task is running.
* Return
* A 64-bit integer containing the current cgroup id based
* on the cgroup within which the current task is running.
*
* void *bpf_get_local_storage(void *map, u64 flags)
* Description
* Get the pointer to the local storage area.
* The type and the size of the local storage is defined
* by the *map* argument.
* The *flags* meaning is specific for each map type,
* and has to be 0 for cgroup local storage.
*
* Depending on the BPF program type, a local storage area
* can be shared between multiple instances of the BPF program,
* running simultaneously.
*
* A user should care about the synchronization by himself.
* For example, by using the **BPF_ATOMIC** instructions to alter
* the shared data.
* Return
* A pointer to the local storage area.
*
* long bpf_sk_select_reuseport(struct sk_reuseport_md *reuse, struct bpf_map *map, void *key, u64 flags)
* Description
* Select a **SO_REUSEPORT** socket from a
* **BPF_MAP_TYPE_REUSEPORT_SOCKARRAY** *map*.
* It checks the selected socket is matching the incoming
* request in the socket buffer.
* Return
* 0 on success, or a negative error in case of failure.
*
* u64 bpf_skb_ancestor_cgroup_id(struct sk_buff *skb, int ancestor_level)
* Description
* Return id of cgroup v2 that is ancestor of cgroup associated
* with the *skb* at the *ancestor_level*. The root cgroup is at
* *ancestor_level* zero and each step down the hierarchy
* increments the level. If *ancestor_level* == level of cgroup
* associated with *skb*, then return value will be same as that
* of **bpf_skb_cgroup_id**\ ().
*
* The helper is useful to implement policies based on cgroups
* that are upper in hierarchy than immediate cgroup associated
* with *skb*.
*
* The format of returned id and helper limitations are same as in
* **bpf_skb_cgroup_id**\ ().
* Return
* The id is returned or 0 in case the id could not be retrieved.
*
* struct bpf_sock *bpf_sk_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
* Description
* Look for TCP socket matching *tuple*, optionally in a child
* network namespace *netns*. The return value must be checked,
* and if non-**NULL**, released via **bpf_sk_release**\ ().
*
* The *ctx* should point to the context of the program, such as
* the skb or socket (depending on the hook in use). This is used
* to determine the base network namespace for the lookup.
*
* *tuple_size* must be one of:
*
* **sizeof**\ (*tuple*\ **->ipv4**)
* Look for an IPv4 socket.
* **sizeof**\ (*tuple*\ **->ipv6**)
* Look for an IPv6 socket.
*
* If the *netns* is a negative signed 32-bit integer, then the
* socket lookup table in the netns associated with the *ctx*
* will be used. For the TC hooks, this is the netns of the device
* in the skb. For socket hooks, this is the netns of the socket.
* If *netns* is any other signed 32-bit value greater than or
* equal to zero then it specifies the ID of the netns relative to
* the netns associated with the *ctx*. *netns* values beyond the
* range of 32-bit integers are reserved for future use.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
*
* This helper is available only if the kernel was compiled with
* **CONFIG_NET** configuration option.
* Return
* Pointer to **struct bpf_sock**, or **NULL** in case of failure.
* For sockets with reuseport option, the **struct bpf_sock**
* result is from *reuse*\ **->socks**\ [] using the hash of the
* tuple.
*
* struct bpf_sock *bpf_sk_lookup_udp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
* Description
* Look for UDP socket matching *tuple*, optionally in a child
* network namespace *netns*. The return value must be checked,
* and if non-**NULL**, released via **bpf_sk_release**\ ().
*
* The *ctx* should point to the context of the program, such as
* the skb or socket (depending on the hook in use). This is used
* to determine the base network namespace for the lookup.
*
* *tuple_size* must be one of:
*
* **sizeof**\ (*tuple*\ **->ipv4**)
* Look for an IPv4 socket.
* **sizeof**\ (*tuple*\ **->ipv6**)
* Look for an IPv6 socket.
*
* If the *netns* is a negative signed 32-bit integer, then the
* socket lookup table in the netns associated with the *ctx*
* will be used. For the TC hooks, this is the netns of the device
* in the skb. For socket hooks, this is the netns of the socket.
* If *netns* is any other signed 32-bit value greater than or
* equal to zero then it specifies the ID of the netns relative to
* the netns associated with the *ctx*. *netns* values beyond the
* range of 32-bit integers are reserved for future use.
*
* All values for *flags* are reserved for future usage, and must
* be left at zero.
*
* This helper is available only if the kernel was compiled with
* **CONFIG_NET** configuration option.
* Return
* Pointer to **struct bpf_sock**, or **NULL** in case of failure.
* For sockets with reuseport option, the **struct bpf_sock**
* result is from *reuse*\ **->socks**\ [] using the hash of the
* tuple.
*
* long bpf_sk_release(void *sock)
* Description
* Release the reference held by *sock*. *sock* must be a
* non-**NULL** pointer that was returned from
* **bpf_sk_lookup_xxx**\ ().
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags)
* Description
* Push an element *value* in *map*. *flags* is one of:
*
* **BPF_EXIST**
* If the queue/stack is full, the oldest element is
* removed to make room for this.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_map_pop_elem(struct bpf_map *map, void *value)
* Description
* Pop an element from *map*.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_map_peek_elem(struct bpf_map *map, void *value)
* Description
* Get an element from *map* without removing it.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_msg_push_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
* Description
* For socket policies, insert *len* bytes into *msg* at offset
* *start*.
*
* If a program of type **BPF_PROG_TYPE_SK_MSG** is run on a
* *msg* it may want to insert metadata or options into the *msg*.
* This can later be read and used by any of the lower layer BPF
* hooks.
*
* This helper may fail if under memory pressure (a malloc
* fails) in these cases BPF programs will get an appropriate
* error and BPF programs will need to handle them.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_msg_pop_data(struct sk_msg_buff *msg, u32 start, u32 len, u64 flags)
* Description
* Will remove *len* bytes from a *msg* starting at byte *start*.
* This may result in **ENOMEM** errors under certain situations if
* an allocation and copy are required due to a full ring buffer.
* However, the helper will try to avoid doing the allocation
* if possible. Other errors can occur if input parameters are
* invalid either due to *start* byte not being valid part of *msg*
* payload and/or *pop* value being to large.
* Return
* 0 on success, or a negative error in case of failure.
*
* long bpf_rc_pointer_rel(void *ctx, s32 rel_x, s32 rel_y)
* Description
* This helper is used in programs implementing IR decoding, to
* report a successfully decoded pointer movement.
*
* The *ctx* should point to the lirc sample as passed into
* the program.
*
* This helper is only available is the kernel was compiled with
* the **CONFIG_BPF_LIRC_MODE2** configuration option set to
* "**y**".
* Return
* 0
*
* long bpf_spin_lock(struct bpf_spin_lock *lock)
* Description
* Acquire a spinlock represented by the pointer *lock*, which is
* stored as part of a value of a map. Taking the lock allows to
* safely update the rest of the fields in that value. The
* spinlock can (and must) later be released with a call to
* **bpf_spin_unlock**\ (\ *lock*\ ).
*
* Spinlocks in BPF programs come with a number of restrictions
* and constraints:
*
* * **bpf_spin_lock** objects are only allowed inside maps of
* types **BPF_MAP_TYPE_HASH** and **BPF_MAP_TYPE_ARRAY** (this
* list could be extended in the future).
* * BTF description of the map is mandatory.
* * The BPF program can take ONE lock at a time, since taking two
* or more could cause dead locks.
* * Only one **struct bpf_spin_lock** is allowed per map element.
* * When the lock is taken, calls (either BPF to BPF or helpers)
* are not allowed.
* * The **BPF_LD_ABS** and **BPF_LD_IND** instructions are not
* allowed inside a spinlock-ed region.
* * The BPF program MUST call **bpf_spin_unlock**\ () to release
* the lock, on all execution paths, before it returns.
* * The BPF program can access **struct bpf_spin_lock** only via
* the **bpf_spin_lock**\ () and **bpf_spin_unlock**\ ()
* helpers. Loading or storing data into the **struct
* bpf_spin_lock** *lock*\ **;** field of a map is not allowed.
* * To use the **bpf_spin_lock**\ () helper, the BTF description
* of the map value must be a struct and have **struct
* bpf_spin_lock** *anyname*\ **;** field at the top level.
* Nested lock inside another struct is not allowed.
* * The **struct bpf_spin_lock** *lock* field in a map value must
* be aligned on a multiple of 4 bytes in that value.
* * Syscall with command **BPF_MAP_LOOKUP_ELEM** does not copy
* the **bpf_spin_lock** field to user space.
* * Syscall with command **BPF_MAP_UPDATE_ELEM**, or update from
* a BPF program, do not update the **bpf_spin_lock** field.
* * **bpf_spin_lock** cannot be on the stack or inside a
* networking packet (it can only be inside of a map values).
* * **bpf_spin_lock** is available to root only.
* * Tracing programs and socket filter programs cannot use
* **bpf_spin_lock**\ () due to insufficient preemption checks
* (but this may change in the future).
* * **bpf_spin_lock** is not allowed in inner maps of map-in-map.
* Return
* 0
*
* long bpf_spin_unlock(struct bpf_spin_lock *lock)
* Description
* Release the *lock* previously locked by a call to
* **bpf_spin_lock**\ (\ *lock*\ ).
* Return
* 0
*
* struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
* Description
* This helper gets a **struct bpf_sock** pointer such
* that all the fields in this **bpf_sock** can be accessed.
* Return
* A **struct bpf_sock** pointer on success, or **NULL** in
* case of failure.
*
* struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
* Description
* This helper gets a **struct bpf_tcp_sock** pointer from a
* **struct bpf_sock** pointer.
* Return
* A **struct bpf_tcp_sock** pointer on success, or **NULL** in
* case of failure.
*
* long bpf_skb_ecn_set_ce(struct sk_buff *skb)
* Description
* Set ECN (Explicit Congestion Notification) field of IP header
* to **CE** (Congestion Encountered) if current value is **ECT**
* (ECN Capable Transport). Otherwise, do nothing. Works with IPv6
* and IPv4.
* Return
* 1 if the **CE** flag is set (either by the current helper call
* or because it was already present), 0 if it is not set.
*
* struct bpf_sock *bpf_get_listener_sock(struct bpf_sock *sk)
* Description
* Return a **struct bpf_sock** pointer in **TCP_LISTEN** state.
* **bpf_sk_release**\ () is unnecessary and not allowed.
* Return
* A **struct bpf_sock** pointer on success, or **NULL** in
* case of failure.
*
* struct bpf_sock *bpf_skc_lookup_tcp(void *ctx, struct bpf_sock_tuple *tuple, u32 tuple_size, u64 netns, u64 flags)
* Description
* Look for TCP socket matching *tuple*, optionally in a child
* network namespace *netns*. The return value must be checked,
* and if non-**NULL**, released via **bpf_sk_release**\ ().
*
* This function is identical to **bpf_sk_lookup_tcp**\ (), except
* that it also returns timewait or request sockets. Use
* **bpf_sk_fullsock**\ () or **bpf_tcp_sock**\ () to access the
* full structure.
*
* This helper is available only if the kernel was compiled with
* **CONFIG_NET** configuration option.
* Return
* Pointer to **struct bpf_sock**, or **NULL** in case of failure.
* For sockets with reuseport option, the **struct bpf_sock**
* result is from *reuse*\ **->socks**\ [] using the hash of the
* tuple.
*
* long bpf_tcp_check_syncookie(void *sk, void *iph, u32 iph_len, struct tcphdr *th, u32 th_len)
* Description
* Check whether *iph* and *th* contain a valid SYN cookie ACK for
* the listening socket in *sk*.
*
* *iph* points to the start of the IPv4 or IPv6 header, while
* *iph_len* contains **sizeof**\ (**struct iphdr**) or
* **sizeof**\ (**struct ipv6hdr**).
*
* *th* points to the start of the TCP header, while *th_len*
* contains the length of the TCP header (at least
* **sizeof**\ (**struct tcphdr**)).
* Return
* 0 if *iph* and *th* are a valid SYN cookie ACK, or a negative
* error otherwise.
*
* long bpf_sysctl_get_name(struct bpf_sysctl *ctx, char *buf, size_t buf_len, u64 flags)
* Description
* Get name of sysctl in /proc/sys/ and copy it into provided by
* program buffer *buf* of size *buf_len*.
*
* The buffer is always NUL terminated, unless it's zero-sized.
*
* If *flags* is zero, full name (e.g. "net/ipv4/tcp_mem") is
* copied. Use **BPF_F_SYSCTL_BASE_NAME** flag to copy base name
* only (e.g. "tcp_mem").
* Return
* Number of character copied (not including the trailing NUL).
*
* **-E2BIG** if the buffer wasn't big enough (*buf* will contain
* truncated name in this case).
*
* long bpf_sysctl_get_current_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
* Description
* Get current value of sysctl as it is presented in /proc/sys
* (incl. newline, etc), and copy it as a string into provided
* by program buffer *buf* of size *buf_len*.
*
* The whole value is copied, no matter what file position user
* space issued e.g. sys_read at.
*
* The buffer is always NUL terminated, unless it's zero-sized.
* Return
* Number of character copied (not including the trailing NUL).
*
* **-E2BIG** if the buffer wasn't big enough (*buf* will contain
* truncated name in this case).
*
* **-EINVAL** if current value was unavailable, e.g. because
* sysctl is uninitialized and read returns -EIO for it.
*
* long bpf_sysctl_get_new_value(struct bpf_sysctl *ctx, char *buf, size_t buf_len)
* Description
* Get new value being written by user space to sysctl (before
* the actual write happens) and copy it as a string into
* provided by program buffer *buf* of size *buf_len*.
*
* User space may write new value at file position > 0.
*
* The buffer is always NUL terminated, unless it's zero-sized.
* Return
* Number of character copied (not including the trailing NUL).
*
* **-E2BIG** if the buffer wasn't big enough (*buf* will contain
* truncated name in this case).
*
* **-EINVAL** if sysctl is being read.
*
* long bpf_sysctl_set_new_value(struct bpf_sysctl *ctx, const char *buf, size_t buf_len)
* Description
* Override new value being written by user space to sysctl with
* value provided by program in buffer *buf* of size *buf_len*.
*
* *buf* should contain a string in same form as provided by user
* space on sysctl write.
*
* User space may write new value at file position > 0. To override
* the whole sysctl value file position should be set to zero.
* Return
* 0 on success.
*
* **-E2BIG** if the *buf_len* is too big.
*
* **-EINVAL** if sysctl is being read.
*
* long bpf_strtol(const char *buf, size_t buf_len, u64 flags, long *res)
* Description
* Convert the initial part of the string from buffer *buf* of
* size *buf_len* to a long integer according to the given base
* and save the result in *res*.
*
* The string may begin with an arbitrary amount of white space
* (as determined by **isspace**\ (3)) followed by a single
* optional '**-**' sign.
*
* Five least significant bits of *flags* encode base, other bits
* are currently unused.
*
* Base must be either 8, 10, 16 or 0 to detect it automatically
* similar to user space **strtol**\ (3).
* Return
* Number of characters consumed on success. Must be positive but
* no more than *buf_len*.
*
* **-EINVAL** if no valid digits were found or unsupported base
* was provided.
*
* **-ERANGE** if resulting value was out of range.
*
* long bpf_strtoul(const char *buf, size_t buf_len, u64 flags, unsigned long *res)
* Description
* Convert the initial part of the string from buffer *buf* of
* size *buf_len* to an unsigned long integer according to the
* given base and save the result in *res*.
*
* The string may begin with an arbitrary amount of white space
* (as determined by **isspace**\ (3)).
*
* Five least significant bits of *flags* encode base, other bits
* are currently unused.
*
* Base must be either 8, 10, 16 or 0 to detect it automatically
* similar to user space **strtoul**\ (3).
* Return
* Number of characters consumed on success. Must be positive but
* no more than *buf_len*.
*
* **-EINVAL** if no valid digits were found or unsupported base
* was provided.
*
* **-ERANGE** if resulting value was out of range.
*
* void *bpf_sk_storage_get(struct bpf_map *map, void *sk, void *value, u64 flags)
* Description
* Get a bpf-local-storage from a *sk*.
*
* Logically, it could be thought of getting the value from
* a *map* with *sk* as the **key**. From this