Linx.Netfilter.Map (Linx v0.1.0)

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An nftables map — a set with associated data per element.

A map is a set where each element is {key, value}. The key matches the set's :key_type and the value matches the map's :data_type. When the :data_type is :verdict, the map is what nft calls a verdict map (vmap) — rule dispatch by lookup.

See Linx.Netfilter.Vmap for the verdict-map-specific constructor helper that wraps Map.new/2 with data_type: :verdict.

Fields

Same as Linx.Netfilter.Set, plus:

  • :data_type — value-type atom. The basic atomic types or :verdict. Concatenations are not yet implemented.

Construction

iex> Map.new("port_to_chain", key_type: :inet_service, data_type: :verdict,
...>          elements: [{22, Linx.Netfilter.Verdict.jump("ssh_in")},
...>                     {80, Linx.Netfilter.Verdict.jump("http_in")}])
{:ok, %Linx.Netfilter.Map{name: "port_to_chain", data_type: :verdict, ...}}

iex> Map.new("dnat_targets", key_type: :inet_service, data_type: :ipv4_addr)
{:ok, %Linx.Netfilter.Map{...}}

Errors: {:error, {:bad_map, reason}}. Element-shape errors: {:error, {:bad_map_element, reason}}.

Summary

Types

data_type()
t()

Functions

add_elements(map, new_elements)

Adds elements to a map, validating each {key, value} against the map's :key_type / :data_type. For verdict maps, values are accepted as %Verdict{} or any input form Verdict.new!/1 understands (and normalised to %Verdict{} in the result).

delete_elements(map, to_remove)

Removes elements from a map by key — both {key, value} and bare key are accepted.

new(name, opts)

Builds a map.

new!(name, opts)

Bang variant of new/2.

Types

data_type()

@type data_type() :: Linx.Netfilter.Set.key_type() | :verdict

t()

@type t() :: %Linx.Netfilter.Map{
  comment: String.t() | nil,
  data_type: data_type(),
  elements: [{term(), term()}],
  flags: [Linx.Netfilter.Set.flag()],
  gc_interval: pos_integer() | nil,
  handle: pos_integer() | nil,
  key_type: Linx.Netfilter.Set.key_type(),
  name: String.t(),
  size: pos_integer() | nil,
  table: String.t() | nil,
  timeout: pos_integer() | nil
}

Functions

add_elements(map, new_elements)

@spec add_elements(t(), [{term(), term()}]) ::
  {:ok, t()} | {:error, {:bad_map_element, term()}}

Adds elements to a map, validating each {key, value} against the map's :key_type / :data_type. For verdict maps, values are accepted as %Verdict{} or any input form Verdict.new!/1 understands (and normalised to %Verdict{} in the result).

delete_elements(map, to_remove)

@spec delete_elements(t(), [term()]) :: {:ok, t()}

Removes elements from a map by key — both {key, value} and bare key are accepted.

new(name, opts)

@spec new(
  String.t(),
  keyword()
) :: {:ok, t()} | {:error, {:bad_map, term()}}

Builds a map.

new!(name, opts)

@spec new!(
  String.t(),
  keyword()
) :: t()

Bang variant of new/2.