bpf.h File Reference

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Functions
Link-related functions
int	bpf_link_detach (int link_fd)
	Detach a link. More...
int	bpf_link_get_fd_by_id (__u32 id)
	Get a file descriptor referring to a link with a given ID. More...
int	bpf_link_get_next_id (__u32 start_id, __u32 *next_id)
	Look for the next link ID greater than a given ID. More...
Map-related functions
int	bpf_create_map (enum bpf_map_type map_type, int key_size, int value_size, int max_entries, __u32 map_flags)
	Create a new map. More...
int	bpf_create_map_xattr (const struct bpf_create_map_attr *create_attr)
	Create a new map. More...
int	bpf_map_delete_elem (int fd, const void *key)
	Look up and delete an element by key in a specified map. More...
int	bpf_map_get_fd_by_id (__u32 id)
	Get a file descriptor referring to a map with a given ID. More...
int	bpf_map_get_next_id (__u32 start_id, __u32 *next_id)
	Look for the next map ID greater than a given ID. More...
int	bpf_map_get_next_key (int fd, const void *key, void *next_key)
	Look up an element by key in a map and get the next key. If the specific key is not found, the first key in the map is passed back. More...
int	bpf_map_lookup_elem (int fd, const void *key, void *value)
	Look up an element by key in a specified map and return its value. More...
int	bpf_map_update_elem (int fd, const void *key, const void *value, __u64 flags)
	Create or update an element (key/value pair) in a specified map. More...
Object-related functions
int	bpf_obj_get (const char *pathname)
	Get a file descriptor for a pinned object by pin path. More...
int	bpf_obj_get_info_by_fd (int bpf_fd, void *info, __u32 *info_len)
	Obtain information about the eBPF object referred to by bpf_fd. This function 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: More...
int	bpf_obj_pin (int fd, const char *pathname)
	Pin an eBPF program or map referred to by fd to the provided pathname. More...
Program-related functions
int	bpf_prog_get_fd_by_id (__u32 id)
	Get a file descriptor referring to a program with a given ID. More...
int	bpf_prog_get_next_id (__u32 start_id, __u32 *next_id)
	Look for the next program ID greater than a given ID. More...

Function Documentation

bpf_create_map()

int bpf_create_map	(	enum bpf_map_type	map_type,
		int	key_size,
		int	value_size,
		int	max_entries,
		__u32	map_flags
	)

Create a new map.

Parameters

[in]	map_type	Type of map to create.
[in]	key_size	Size in bytes of keys.
[in]	value_size	Size in bytes of values.
[in]	max_entries	Maximum number of entries in the map.
[in]	map_flags	Flags (currently 0).

Returns

A new file descriptor that refers to the map. A negative value indicates an error occurred and errno was set.

Exceptions

EINVAL	An invalid argument was provided.
ENOMEM	Out of memory.

bpf_create_map_xattr()

int bpf_create_map_xattr

(

const struct bpf_create_map_attr *

create_attr

)

Create a new map.

Parameters

[in]

create_attr

Structure of attributes using which a map gets created.

Returns

A new file descriptor that refers to the map. A negative value indicates an error occurred and errno was set.

Exceptions

EINVAL	An invalid argument was provided.
ENOMEM	Out of memory.

bpf_link_detach()

int bpf_link_detach

(

int

link_fd

)

Detach a link.

Parameters

[in]

link_fd

File descriptor of link to detach.

Return values

0	The operation was successful.
<0	An error occured, and errno was set.

Exceptions

EBADF

The file descriptor was not found.

See also

bpf_link__destroy

bpf_link__disconnect

bpf_link_get_fd_by_id()

int bpf_link_get_fd_by_id

(

__u32

id

)

Get a file descriptor referring to a link with a given ID.

Parameters

[in]

id

ID of link to find.

Returns

A new file descriptor that refers to the link. A negative value indicates an error occurred and errno was set.

Exceptions

ENOENT

No link with the specified ID was found.

bpf_link_get_next_id()

int bpf_link_get_next_id	(	__u32	start_id,
		__u32 *	next_id
	)

Look for the next link ID greater than a given ID.

Parameters

[in]	start_id	ID to look for an ID after. The start_id need not exist.
[out]	next_id	Pointer to where to write the next ID.

Return values

0	The operation was successful.
<0	An error occured, and errno was set.

Exceptions

ENOENT

No more IDs found.

bpf_map_delete_elem()

int bpf_map_delete_elem	(	int	fd,
		const void *	key
	)

Look up and delete an element by key in a specified map.

Parameters

[in]	fd	File descriptor of map to update.
[in]	key	Pointer to key to look up.

Return values

0	The operation was successful.
<0	An error occured, and errno was set.

Exceptions

EINVAL	An invalid argument was provided.
EBADF	The file descriptor was not found.
ENOMEM	Out of memory.

bpf_map_get_fd_by_id()

int bpf_map_get_fd_by_id

(

__u32

id

)

Get a file descriptor referring to a map with a given ID.

Parameters

[in]

id

ID of map to find.

Returns

A new file descriptor that refers to the map. A negative value indicates an error occurred and errno was set.

Exceptions

ENOENT

No map with the specified ID was found.

bpf_map_get_next_id()

int bpf_map_get_next_id	(	__u32	start_id,
		__u32 *	next_id
	)

Look for the next map ID greater than a given ID.

Parameters

[in]	start_id	ID to look for an ID after. The start_id need not exist.
[out]	next_id	Pointer to where to write the next ID.

Return values

0	The operation was successful.
<0	An error occured, and errno was set.

Exceptions

ENOENT

No more IDs found.

bpf_map_get_next_key()

int bpf_map_get_next_key	(	int	fd,
		const void *	key,
		void *	next_key
	)

Look up an element by key in a map and get the next key. If the specific key is not found, the first key in the map is passed back.

Parameters

[in]	fd	File descriptor of map.
[in]	key	Pointer to key to look up.
[out]	next_key	Pointer to memory in which to write the next key.

Return values

0	The operation was successful.
<0	An error occured, and errno was set.

Exceptions

EINVAL	An invalid argument was provided.
EBADF	The file descriptor was not found.
ENOMEM	Out of memory.

bpf_map_lookup_elem()

int bpf_map_lookup_elem	(	int	fd,
		const void *	key,
		void *	value
	)

Look up an element by key in a specified map and return its value.

Parameters

[in]	fd	File descriptor of map.
[in]	key	Pointer to key to look up.
[out]	value	Pointer to memory in which to write the value.

Return values

0	The operation was successful.
<0	An error occured, and errno was set.

Exceptions

EINVAL	An invalid argument was provided.
EBADF	The file descriptor was not found.
ENOMEM	Out of memory.

bpf_map_update_elem()

int bpf_map_update_elem	(	int	fd,
		const void *	key,
		const void *	value,
		__u64	flags
	)

Create or update an element (key/value pair) in a specified map.

Parameters

[in]	fd	File descriptor of map.
[in]	key	Pointer to key.
[in]	value	Pointer to value.
[in]	flags	Flags (currently 0).

Exceptions

EINVAL	An invalid argument was provided.
EBADF	The file descriptor was not found.
ENOMEM	Out of memory.

bpf_obj_get()

int bpf_obj_get

(

const char *

pathname

)

Get a file descriptor for a pinned object by pin path.

Parameters

[in]

path

Pin path for the object.

Returns

file descriptor for the pinned object, or -1 if not found.

bpf_obj_get_info_by_fd()

int bpf_obj_get_info_by_fd	(	int	bpf_fd,
		void *	info,
		__u32 *	info_len
	)

Obtain information about the eBPF object referred to by bpf_fd. This function 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_link_info
• struct bpf_map_info
• struct bpf_prog_info

Parameters

[in]	bpf_fd	File descriptor referring to an eBPF object.
[out]	info	Pointer to memory in which to write the info obtained.
[in,out]	info_len	On input, contains the maximum number of bytes to write into the info. On output, contains the actual number of bytes written.

Return values

0	The operation was successful.
<0	An error occured, and errno was set.

bpf_obj_pin()

int bpf_obj_pin	(	int	fd,
		const char *	pathname
	)

Pin an eBPF program or map referred to by fd to the provided pathname.

Parameters

[in]	fd	File descriptor referring to the program or map to pin.
[in]	pathname	Path name to pin the object to.

Return values

0	The operation was successful.
<0	An error occured, and errno was set.

bpf_prog_get_fd_by_id()

int bpf_prog_get_fd_by_id

(

__u32

id

)

Get a file descriptor referring to a program with a given ID.

Parameters

[in]

id

ID of program to find.

Returns

A new file descriptor that refers to the program. A negative value indicates an error occurred and errno was set.

Exceptions

ENOENT

No program with the specified ID was found.

bpf_prog_get_next_id()

int bpf_prog_get_next_id	(	__u32	start_id,
		__u32 *	next_id
	)

Look for the next program ID greater than a given ID.

Parameters

[in]	start_id	ID to look for an ID after. The start_id need not exist.
[out]	next_id	Pointer to where to write the next ID.

Return values

0	The operation was successful.
<0	An error occured, and errno was set.

Exceptions

ENOENT

No more IDs found.