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defmodule RoutingTable do
alias RoutingTable.TreeBitmap
defstruct [:i4, :i6, :ets]
@opaque t() :: %__MODULE__{}
@type masklen :: non_neg_integer()
@moduledoc """
Efficient routing table.
```elixir
table = RoutingTable.new()
RoutingTable.add(table, {10, 69, 0, 0}, 16, :vpn)
RoutingTable.add(table, {10, 69, 1, 0}, 24, :lan)
:vpn = RoutingTable.longest_match(table, {10, 69, 2, 1})
:lan = RoutingTable.longest_match(table, {10, 69, 1, 1})
nil = RoutingTable.longest_match(table, {10, 68, 1, 1})
```
"""
def new(_opts \\ []) do
%__MODULE__{i4: TreeBitmap.new(), i6: TreeBitmap.new(), ets: :ets.new(__MODULE__, [:public])}
end
@spec add(t(), :inet.ip_address(), masklen(), any()) :: nil | any()
def add(tree, ip, masklen, value)
def add(tree, {a, b, c, d}, masklen, value) do
add(tree, tree.i4, {:inet4, a, b, c, d}, masklen, value)
end
def add(tree, {a, b, c, d, e, f, g, h}, masklen, value) do
add(tree, tree.i6, {:inet6, a, b, c, d, e, f, g, h}, masklen, value)
end
@spec remove(t(), :inet.ip_address(), masklen()) :: nil | any()
def remove(tree, ip, masklen)
def remove(tree, {a, b, c, d}, masklen) do
remove(tree, tree.i4, {:inet4, a, b, c, d}, masklen)
end
def remove(tree, {a, b, c, d, e, f, g, h}, masklen) do
remove(tree, tree.i6, {:inet6, a, b, c, d, e, f, g, h}, masklen)
end
@spec longest_match(t(), :inet.ip_address()) :: map() | nil
def longest_match(tree, ip)
def longest_match(tree, {a, b, c, d}) do
longest_match(tree, tree.i4, {:inet4, a, b, c, d})
end
def longest_match(tree, {a, b, c, d, e, f, g, h}) do
longest_match(tree, tree.i6, {:inet6, a, b, c, d, e, f, g, h})
end
@spec longest_match?(t(), :inet.ip_address()) :: boolean()
def longest_match?(tree, ip)
def longest_match?(tree, {a, b, c, d}) do
longest_match?(tree, tree.i4, {:inet4, a, b, c, d})
end
def longest_match?(tree, {a, b, c, d, e, f, g, h}) do
longest_match?(tree, tree.i6, {:inet6, a, b, c, d, e, f, g, h})
end
@spec exact_match(t(), :inet.ip_address(), masklen()) :: map() | nil
def exact_match(tree, ip, masklen)
def exact_match(tree, {a, b, c, d}, masklen) do
exact_match(tree, tree.i4, {:inet4, a, b, c, d}, masklen)
end
def exact_match(tree, {a, b, c, d, e, f, g, h}, masklen) do
exact_match(tree, tree.i6, {:inet6, a, b, c, d, e, f, g, h}, masklen)
end
@spec exact_match?(t(), :inet.ip_address(), masklen()) :: boolean()
def exact_match?(tree, ip, masklen)
def exact_match?(tree, {a, b, c, d}, masklen) do
exact_match?(tree, tree.i4, {:inet4, a, b, c, d}, masklen)
end
def exact_match?(tree, {a, b, c, d, e, f, g, h}, masklen) do
exact_match?(tree, tree.i6, {:inet6, a, b, c, d, e, f, g, h}, masklen)
end
@type tree_memory() :: {nodes :: non_neg_integer(), results :: non_neg_integer()}
@spec memory(t()) :: %{inet4: tree_memory(), inet6: tree_memory(), ets: non_neg_integer()}
def memory(tree) do
%{inet4: TreeBitmap.memory(tree.i4), inet6: TreeBitmap.memory(tree.i6), ets: :ets.info(tree.ets, :memory)}
end
@spec length(t()) :: %{inet4: non_neg_integer(), inet6: non_neg_integer(), ets: non_neg_integer()}
def length(tree) do
%{inet4: TreeBitmap.length(tree.i4), inet6: TreeBitmap.length(tree.i6), ets: :ets.info(tree.ets, :size)}
end
defp add(tree, tbm, ip, masklen, value) do
id = case :ets.match(tree.ets, {:'$1', :_, value}) do
[[id]] ->
:ets.update_counter(tree.ets, id, 1)
id
[] ->
id = :ets.update_counter(tree.ets, {__MODULE__, :counter}, 1, {{__MODULE__, :counter}, -1, 0})
:ets.insert(tree.ets, {id, 1, value})
id
end
{:ok, prev_id} = TreeBitmap.add(tbm, ip, masklen, id)
prev = if prev_id do
[{^prev_id, _refc, value}] = :ets.lookup(tree.ets, prev_id)
refc = :ets.update_counter(tree.ets, id, -1)
if refc < 1, do: :ets.delete(tree.ets, prev_id)
value
end
prev
end
defp remove(tree, tbm, ip, masklen) do
{:ok, id} = TreeBitmap.remove(tbm, ip, masklen)
prev = if id do
[{^id, _refc, value}] = :ets.lookup(tree.ets, id)
refc = :ets.update_counter(tree.ets, id, -1)
if refc < 1, do: :ets.delete(tree.ets, id)
value
end
prev
end
defp longest_match(tree, tbm, ip) do
case TreeBitmap.longest_match(tbm, ip) do
{:ok, prefix, masklen, id} ->
[{^id, _refc, value}] = :ets.lookup(tree.ets, id)
%{prefix: to_inet(prefix), len: masklen, value: value}
{:ok, nil} ->
nil
end
end
defp longest_match?(_, tbm, ip) do
case TreeBitmap.longest_match(tbm, ip) do
{:ok, nil} -> false
{:ok, _, _, _} -> true
end
end
defp exact_match(tree, tbm, ip, masklen) do
case TreeBitmap.exact_match(tbm, ip, masklen) do
{:ok, nil} ->
nil
{:ok, id} ->
[{^id, _refc, value}] = :ets.lookup(tree.ets, id)
value
end
end
defp exact_match?(_, tbm, ip, masklen) do
case TreeBitmap.exact_match(tbm, ip, masklen) do
{:ok, nil} -> false
{:ok, _} -> true
end
end
defp to_inet({:inet4, a, b, c, d}), do: {a, b, c, d}
defp to_inet({:inet6, a, b, c, d, e, f, g, h}), do: {a, b, c, d, e, f, g, h}
end
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