Lunatik

• Index

Contents

• Functions
• Class map_queue

Modules

• bpf
• bpf.map
• byteorder
• class
• completion
• cpu
• crypto
• darken
• data
• device
• fifo
• hid
• lighten
• linux
• linux.bpf
• linux.eth
• linux.genl
• linux.kbd
• linux.netdev
• linux.netlink
• linux.nf
• linux.nl80211
• linux.notify
• linux.rtnetlink
• linux.signal
• linux.socket
• linux.stat
• linux.syscall
• linux.task
• linux.tc
• linux.vt
• linux.xdp
• lunatik
• lunatik.runner
• mailbox
• net
• netfilter
• netlink
• netlink.channel
• netlink.genl
• netlink.message
• netlink.nl80211
• netlink.nl80211.ap
• netlink.nl80211.interface
• netlink.nl80211.object
• netlink.nl80211.station
• netlink.nl80211.wiphy
• netlink.rt
• netlink.rt.addr
• netlink.rt.link
• netlink.rt.object
• netlink.rt.route
• netlink.rt.rule
• netlink.session
• notifier
• probe
• rcu
• set
• signal
• skb
• socket
• socket.inet
• socket.raw
• socket.unix
• struct
• syscall
• syscall.table
• task
• tc
• thread
• xdp

Classes

• crypto.hkdf
• crypto_aead
• crypto_comp
• crypto_rng
• crypto_shash
• crypto_skcipher
• skb.attr

Topics

• README

Module bpf.map

High-level view over pinned eBPF maps.

Each constructor mirrors the one in bpf, taking the packing spec of what the map holds. Key-value maps become table proxies: indexing looks values up, assignment updates, assigning nil deletes, and pairs iterates. Keyless maps become objects, with push, pop and peek.

Keys and values are opaque fixed-size buffers to eBPF. A spec is either a string.pack format (e.g. "I4", "c6") or a struct codec, and says both how many bytes it takes, validated against the map on open, and how to read them. Specs that pack a single value take and return it as a scalar; multi-value formats and struct codecs take and return an array of values, in field order.

Operations on a table proxy come from outside it (close and info are module functions, as in Lua's table library or rcu.map), so any key the spec can encode is a valid map key.

Conditional updates (BPF_NOEXIST/BPF_EXIST) and the boolean results belong to the raw API.

See also:

bpf

Usage:

local map = require("bpf.map")

local counters <close> = map.hash("/sys/fs/bpf/counters", "I4", "I4")
counters[1] = 42
print(counters[1])
counters[1] = nil                 -- delete
for key, value in pairs(counters) do print(key, value) end

local events <close> = map.queue("/sys/fs/bpf/events", "I8")
events:push(1234)
print(events:pop())

Functions

array (pathname, keyspec, valuespec)	Opens a pinned array map as a table.
close (proxy)	Releases the map reference.
hash (pathname, keyspec, valuespec)	Opens a pinned hash map as a table.
info (proxy)	Returns the map properties, as bpf map info.
lru_hash (pathname, keyspec, valuespec)	Opens a pinned LRU hash map as a table.
queue (pathname, valuespec)	Opens a pinned queue map (FIFO).
stack (pathname, valuespec)	Opens a pinned stack map (LIFO).

Class map_queue

map_queue:close ()	Releases the map reference.
map_queue:info ()	Returns the map properties, as bpf map info.
map_queue:peek ()	Returns the next value, leaving it in the map.
map_queue:pop ()	Removes and returns the next value.
map_queue:push (value)	Inserts a value.

Functions

array (pathname, keyspec, valuespec)

Opens a pinned array map as a table. Keys are the u32 indices of the array.

Parameters:

• pathname string Path to the pinned map.
• keyspec string or table string.pack format or struct codec for the key.
• valuespec string or table string.pack format or struct codec for the value.

Returns:

map_hash the table proxy

Raises:

Error if the map cannot be opened or a spec does not match its sizes.

close (proxy)

Releases the map reference. Also wired as the proxy's __close metamethod.

Parameters:

• proxy map_hash the table proxy

hash (pathname, keyspec, valuespec)

Opens a pinned hash map as a table.

Parameters:

• pathname string Path to the pinned map.
• keyspec string or table string.pack format or struct codec for the key.
• valuespec string or table string.pack format or struct codec for the value.

Returns:

map_hash the table proxy

Raises:

Error if the map cannot be opened or a spec does not match its sizes.

info (proxy)

Returns the map properties, as bpf map info.

Parameters:

• proxy map_hash the table proxy

Returns:

table type, key_size, value_size and max_entries

lru_hash (pathname, keyspec, valuespec)

Opens a pinned LRU hash map as a table.

Parameters:

• pathname string Path to the pinned map.
• keyspec string or table string.pack format or struct codec for the key.
• valuespec string or table string.pack format or struct codec for the value.

Returns:

map_hash the table proxy

Raises:

Error if the map cannot be opened or a spec does not match its sizes.

queue (pathname, valuespec)

Opens a pinned queue map (FIFO).

Parameters:

• pathname string Path to the pinned map.
• valuespec string or table string.pack format or struct codec for the value.

Returns:

map_queue the map object

Raises:

Error if the map cannot be opened or the spec does not match its value size.

stack (pathname, valuespec)

Opens a pinned stack map (LIFO).

Parameters:

• pathname string Path to the pinned map.
• valuespec string or table string.pack format or struct codec for the value.

Returns:

map_queue the map object

Raises:

Error if the map cannot be opened or the spec does not match its value size.

Class map_queue

map_queue:close ()

Releases the map reference. Also wired as the object's __close metamethod.

map_queue:info ()

Returns the map properties, as bpf map info.

Returns:

table type, key_size, value_size and max_entries

map_queue:peek ()

Returns the next value, leaving it in the map.

Returns:

the value, or nil if the map is empty

Raises:

Error if the operation fails.

map_queue:pop ()

Removes and returns the next value.

Returns:

the value, or nil if the map is empty

Raises:

Error if the operation fails.

map_queue:push (value)

Inserts a value.

Parameters:

• value the value to insert, as the spec encodes it

Returns:

boolean false if the map is full, true otherwise

Raises:

Error if the operation fails.