@@ -93,7 +93,717 @@ union bpf_iter_link_info {
} map;
};
-/* BPF syscall commands, see bpf(2) man-page for details. */
+/* 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.
+ *
+ * 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.
+ *
+ * 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**
+ *
+ * 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.
+ *
+ * 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,