Implement parsing of strings into prefixes.
This commit is contained in:
James Harton
parent
99596e4bf7
commit
78885b2b2d
7 changed files with 381 additions and 31 deletions
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@ -171,7 +171,7 @@ defmodule IP.Address do
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"""
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@spec from_string(binary, ip_version) :: {:ok, t} | {:error, term}
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def from_string(address, 4) when is_binary(address) do
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case :inet.parse_ipv4_address(String.to_charlist(address)) do
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case :inet.parse_ipv4strict_address(String.to_charlist(address)) do
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{:ok, addr} ->
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addr = addr
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|> Tuple.to_list()
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@ -269,6 +269,80 @@ defmodule IP.Address do
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:: Prefix.t
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def to_prefix(%Address{} = address, length), do: IP.Prefix.new(address, length)
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@doc """
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Returns the IP version of the address.
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## Examples
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iex> "192.0.2.1"
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...> |> IP.Address.from_string!
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...> |> IP.Address.version()
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4
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iex> "2001:db8::1"
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...> |> IP.Address.from_string!
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...> |> IP.Address.version()
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6
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"""
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@spec version(t) :: 4 | 6
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def version(%Address{version: version}), do: version
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@doc """
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Returns the IP Address as an integer
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## Examples
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iex> "192.0.2.1"
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...> |> IP.Address.from_string!
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...> |> IP.Address.to_integer()
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3221225985
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iex> "2001:db8::1"
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...> |> IP.Address.from_string!
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...> |> IP.Address.to_integer()
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42540766411282592856903984951653826561
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"""
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@spec to_integer(t) :: ipv4 | ipv6
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def to_integer(%Address{address: address}), do: address
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@doc """
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Returns true if `address` is version 6.
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## Examples
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iex> "192.0.2.1"
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...> |> IP.Address.from_string!()
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...> |> IP.Address.v6?
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false
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iex> "2001:db8::"
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...> |> IP.Address.from_string!()
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...> |> IP.Address.v6?
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true
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"""
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@spec v6?(t) :: true | false
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def v6?(%Address{version: 6} = _address), do: true
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def v6?(_address), do: false
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@doc """
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Returns true if `address` is version 4.
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## Examples
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iex> "192.0.2.1"
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...> |> IP.Address.from_string!()
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...> |> IP.Address.v4?
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true
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iex> "2001:db8::"
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...> |> IP.Address.from_string!()
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...> |> IP.Address.v4?
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false
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"""
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@spec v4?(t) :: true | false
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def v4?(%Address{version: 4} = _address), do: true
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def v4?(_address), do: false
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defp from_bytes([a, b, c, d]) do
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(a <<< 24) + (b <<< 16) + (c <<< 8) + d
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end
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194
lib/ip/prefix.ex
194
lib/ip/prefix.ex
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@ -1,7 +1,9 @@
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defmodule IP.Prefix do
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alias IP.{Prefix, Address}
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alias IP.Prefix.{Parser, InvalidPrefix, Helpers}
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defstruct ~w(address mask)a
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use Bitwise
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import Helpers
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@moduledoc """
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Defines an IP prefix, otherwise known as a subnet.
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@ -36,13 +38,108 @@ defmodule IP.Prefix do
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%Prefix{address: Address.from_integer!(address &&& mask, 6), mask: mask}
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end
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@doc """
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Create a prefix by attempting to parse a string of unknown version.
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Calling `from_string/2` is faster if you know the IP version of the prefix.
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## Examples
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iex> "192.0.2.1/24"
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...> |> IP.Prefix.from_string()
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...> |> inspect()
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"{:ok, #IP.Prefix<192.0.2.0/24>}"
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iex> "192.0.2.1/255.255.255.0"
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...> |> IP.Prefix.from_string()
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...> |> inspect()
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"{:ok, #IP.Prefix<192.0.2.0/24>}"
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iex> "2001:db8::/64"
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...> |> IP.Prefix.from_string()
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...> |> inspect()
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"{:ok, #IP.Prefix<2001:db8::/64>}"
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"""
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@spec from_string(binary) :: {:ok, t} | {:error, term}
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def from_string(prefix), do: Parser.parse(prefix)
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@doc """
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Create a prefix by attempting to parse a string of specified IP version.
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## Examples
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iex> "192.0.2.1/24"
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...> |> IP.Prefix.from_string(4)
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...> |> inspect()
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"{:ok, #IP.Prefix<192.0.2.0/24>}"
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iex> "192.0.2.1/255.255.255.0"
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...> |> IP.Prefix.from_string(4)
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...> |> inspect()
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"{:ok, #IP.Prefix<192.0.2.0/24>}"
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iex> "2001:db8::/64"
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...> |> IP.Prefix.from_string(4)
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{:error, "Error parsing IPv4 prefix"}
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"""
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@spec from_string(binary, 4 | 6) :: {:ok, t} | {:error, term}
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def from_string(prefix, version), do: Parser.parse(prefix, version)
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@doc """
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Create a prefix by attempting to parse a string of unknown version.
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Calling `from_string!/2` is faster if you know the IP version of the prefix.
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## Examples
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iex> "192.0.2.1/24"
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...> |> IP.Prefix.from_string!()
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#IP.Prefix<192.0.2.0/24>
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iex> "192.0.2.1/255.255.255.0"
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...> |> IP.Prefix.from_string!()
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#IP.Prefix<192.0.2.0/24>
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iex> "2001:db8::/64"
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...> |> IP.Prefix.from_string!()
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#IP.Prefix<2001:db8::/64>
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"""
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@spec from_string!(binary) :: t
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def from_string!(prefix) do
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case from_string(prefix) do
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{:ok, prefix} -> prefix
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{:error, msg} -> raise(InvalidPrefix, message: msg)
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end
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end
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@doc """
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Create a prefix by attempting to parse a string of specified IP version.
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## Examples
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iex> "192.0.2.1/24"
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...> |> IP.Prefix.from_string!(4)
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#IP.Prefix<192.0.2.0/24>
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iex> "192.0.2.1/255.255.255.0"
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...> |> IP.Prefix.from_string!(4)
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#IP.Prefix<192.0.2.0/24>
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"""
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@spec from_string!(binary, 4 | 6) :: t
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def from_string!(prefix, version) do
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case from_string(prefix, version) do
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{:ok, prefix} -> prefix
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{:error, msg} -> raise(InvalidPrefix, message: msg)
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end
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end
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@doc """
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Returns the bit-length of the prefix.
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## Example
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iex> IP.Address.from_string!("192.0.2.1")
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...> |> IP.Address.to_prefix(24)
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iex> "192.0.2.1/24"
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...> |> IP.Prefix.from_string!()
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...> |> IP.Prefix.length()
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24
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"""
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@ -54,26 +151,57 @@ defmodule IP.Prefix do
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## Example
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iex> IP.Address.from_string!("192.0.2.1")
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...> |> IP.Address.to_prefix(24)
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iex> IP.Prefix.from_string!("192.0.2.1/24")
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...> |> IP.Prefix.mask()
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0b11111111111111111111111100000000
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"""
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@spec mask(t) :: non_neg_integer
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def mask(%Prefix{mask: mask}), do: mask
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@doc """
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Returns an old-fashioned subnet mask for IPv4 prefixes.
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## Example
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iex> IP.Prefix.from_string!("192.0.2.0/24")
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...> |> IP.Prefix.subnet_mask()
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"255.255.255.0"
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"""
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@spec subnet_mask(t) :: binary
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def subnet_mask(%Prefix{mask: mask, address: %Address{version: 4}}) do
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mask
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|> Address.from_integer!(4)
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|> Address.to_string()
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end
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@doc """
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Returns an "cisco style" wildcard mask for IPv4 prefixes.
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## Example
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iex> IP.Prefix.from_string!("192.0.2.0/24")
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...> |> IP.Prefix.wildcard_mask()
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"0.0.0.255"
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"""
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@spec wildcard_mask(t) :: binary
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def wildcard_mask(%Prefix{mask: mask, address: %Address{version: 4}}) do
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mask
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|> bnot()
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|> band(@ipv4_mask)
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|> Address.from_integer!(4)
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|> Address.to_string()
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end
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@doc """
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Returns the first address in the prefix.
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## Examples
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iex> IP.Address.from_string!("192.0.2.128")
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...> |> IP.Address.to_prefix(24)
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iex> IP.Prefix.from_string!("192.0.2.128/24")
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...> |> IP.Prefix.first()
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#IP.Address<192.0.2.0>
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iex> IP.Address.from_string!("2001:db8::128")
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...> |> IP.Address.to_prefix(64)
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iex> IP.Prefix.from_string!("2001:db8::128/64")
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...> |> IP.Prefix.first()
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#IP.Address<2001:db8::>
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"""
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@ -87,13 +215,11 @@ defmodule IP.Prefix do
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## Examples
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iex> IP.Address.from_string!("192.0.2.128")
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...> |> IP.Address.to_prefix(24)
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iex> IP.Prefix.from_string!("192.0.2.128/24")
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...> |> IP.Prefix.last()
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#IP.Address<192.0.2.255>
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iex> IP.Address.from_string!("2001:db8::128")
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...> |> IP.Address.to_prefix(64)
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iex> IP.Prefix.from_string!("2001:db8::128/64")
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...> |> IP.Prefix.last()
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#IP.Address<2001:db8::ffff:ffff:ffff:ffff>
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"""
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@ -106,15 +232,38 @@ defmodule IP.Prefix do
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Address.from_integer!(address, 6)
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end
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def contains?(%Prefix{address: %Address{address: addr0, version: 4}, mask: mask}, %Address{address: addr1, version: 4})
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@doc """
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Returns `true` or `false` depending on whether the supplied `address` is
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contained within `prefix`.
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## Examples
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iex> IP.Prefix.from_string!("192.0.2.0/24")
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...> |> IP.Prefix.contains?(IP.Address.from_string!("192.0.2.127"))
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true
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iex> IP.Prefix.from_string!("192.0.2.0/24")
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...> |> IP.Prefix.contains?(IP.Address.from_string!("198.51.100.1"))
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false
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iex> IP.Prefix.from_string!("2001:db8::/64")
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...> |> IP.Prefix.contains?(IP.Address.from_string!("2001:db8::1"))
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true
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iex> IP.Prefix.from_string!("2001:db8::/64")
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...> |> IP.Prefix.contains?(IP.Address.from_string!("2001:db8:1::1"))
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false
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"""
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def contains?(%Prefix{address: %Address{address: addr0, version: 4}, mask: mask} = _prefix,
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%Address{address: addr1, version: 4} = _address)
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when (addr0 &&& mask) <= addr1
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and ((addr0 &&& mask) + (~~~(mask) &&& @ipv4_mask)) >= addr1
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do
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true
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end
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def contains?(%Prefix{address: %Address{address: addr0, version: 6}, mask: mask},
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%Address{address: addr1, version: 6})
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def contains?(%Prefix{address: %Address{address: addr0, version: 6}, mask: mask} = _prefix,
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%Address{address: addr1, version: 6} = _address)
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when (addr0 &&& mask) <= addr1
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and ((addr0 &&& mask) + (~~~(mask) &&& @ipv6_mask)) >= addr1
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do
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@ -123,19 +272,4 @@ defmodule IP.Prefix do
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def contains?(_prefix, _address), do: false
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defp calculate_mask_from_length(length, mask_length) do
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pad = mask_length - length
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0..(length - 1)
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|> Enum.reduce(0, fn (i, mask) -> mask + (1 <<< i + pad) end)
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end
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defp calculate_length_from_mask(mask) do
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mask
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|> Integer.digits(2)
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|> Stream.filter(fn
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1 -> true
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0 -> false
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end)
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|> Enum.count()
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end
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end
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23
lib/ip/prefix/helpers.ex
Normal file
23
lib/ip/prefix/helpers.ex
Normal file
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@ -0,0 +1,23 @@
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defmodule IP.Prefix.Helpers do
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use Bitwise
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@moduledoc false
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@doc false
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def calculate_mask_from_length(length, mask_length) do
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pad = mask_length - length
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0..(length - 1)
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|> Enum.reduce(0, fn (i, mask) -> mask + (1 <<< i + pad) end)
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end
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@doc false
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def calculate_length_from_mask(mask) do
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mask
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|> Integer.digits(2)
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|> Stream.filter(fn
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1 -> true
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0 -> false
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end)
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|> Enum.count()
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end
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end
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8
lib/ip/prefix/invalid_prefix.ex
Normal file
8
lib/ip/prefix/invalid_prefix.ex
Normal file
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@ -0,0 +1,8 @@
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defmodule IP.Prefix.InvalidPrefix do
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defexception ~w(message)a
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@moduledoc """
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An exception raised by the bang-version functions in `IP.Prefix` when the
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supplied value is invalid.
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"""
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end
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103
lib/ip/prefix/parser.ex
Normal file
103
lib/ip/prefix/parser.ex
Normal file
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@ -0,0 +1,103 @@
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defmodule IP.Prefix.Parser do
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alias IP.{Prefix, Address}
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import IP.Prefix.Helpers
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@moduledoc """
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Used internally by `IP.Prefix.from_string` to parse IP prefixes.
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"""
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@doc """
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Attempts to parse a `prefix` of unknown IP version.
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This attempts to parse as IPv4 and then as IPv6. Obviously it's slower
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than parsing a specific version if you know that at call time.
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## Examples
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iex> "192.0.2.1/25"
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...> |> IP.Prefix.Parser.parse()
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...> |> inspect()
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"{:ok, #IP.Prefix<192.0.2.0/25>}"
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iex> "2001:db8::/64"
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...> |> IP.Prefix.Parser.parse()
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...> |> inspect()
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"{:ok, #IP.Prefix<2001:db8::/64>}"
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"""
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@spec parse(binary) :: Prefix.t
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def parse(prefix) do
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case parse(prefix, 4) do
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{:ok, prefix} -> {:ok, prefix}
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_ ->
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case parse(prefix, 6) do
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{:ok, prefix} -> {:ok, prefix}
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_ -> {:error, "Unable to parse IP prefix"}
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end
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end
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end
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@doc """
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Attempts to parse a `prefix` of a specific IP `version` from a string.
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## Examples
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iex> "192.0.2.1/25"
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...> |> IP.Prefix.Parser.parse(4)
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...> |> inspect()
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"{:ok, #IP.Prefix<192.0.2.0/25>}"
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iex> "2001:db8::/64"
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...> |> IP.Prefix.Parser.parse(6)
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...> |> inspect()
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"{:ok, #IP.Prefix<2001:db8::/64>}"
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"""
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@spec parse(binary, 4 | 6) :: Prefix.t
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def parse(prefix, 4 = _version) do
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with {:ok, address, mask} <- ensure_contains_slash(prefix),
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{:ok, address} <- Address.from_string(address, 4),
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{:ok, mask} <- parse_v4_mask(mask)
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do
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{:ok, Prefix.new(address, mask)}
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else
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_ -> {:error, "Error parsing IPv4 prefix"}
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end
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end
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def parse(prefix, 6 = _version) do
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with {:ok, address, mask} <- ensure_contains_slash(prefix),
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{:ok, address} <- Address.from_string(address, 6),
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{:ok, mask} <- parse_v6_mask(mask)
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do
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{:ok, Prefix.new(address, mask)}
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else
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_ -> {:error, "Error parsing IPv6 prefix"}
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end
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end
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defp ensure_contains_slash(prefix) do
|
||||
case String.split(prefix, "/") do
|
||||
[address, mask] -> {:ok, address, mask}
|
||||
_ -> {:error, "Missing \"/\" in IP prefix"}
|
||||
end
|
||||
end
|
||||
|
||||
defp parse_v4_mask(mask) do
|
||||
case Address.from_string(mask, 4) do
|
||||
{:ok, address} ->
|
||||
mask = address
|
||||
|> Address.to_integer()
|
||||
|> calculate_length_from_mask()
|
||||
{:ok, mask}
|
||||
_ ->
|
||||
{:ok, String.to_integer(mask)}
|
||||
end
|
||||
rescue
|
||||
ArgumentError -> {:error, "Unable to parse IPv4 mask"}
|
||||
end
|
||||
|
||||
defp parse_v6_mask(mask) do
|
||||
{:ok, String.to_integer(mask)}
|
||||
rescue
|
||||
ArgumentError -> {:error, "Unable to parse IPv6 mask"}
|
||||
end
|
||||
end
|
||||
4
test/ip/prefix/helpers_test.exs
Normal file
4
test/ip/prefix/helpers_test.exs
Normal file
|
|
@ -0,0 +1,4 @@
|
|||
defmodule IPPrefixHelpersTest do
|
||||
use ExUnit.Case
|
||||
doctest IP.Prefix.Helpers
|
||||
end
|
||||
4
test/ip/prefix/parser_test.exs
Normal file
4
test/ip/prefix/parser_test.exs
Normal file
|
|
@ -0,0 +1,4 @@
|
|||
defmodule IPPrefixParserTest do
|
||||
use ExUnit.Case
|
||||
doctest IP.Prefix.Parser
|
||||
end
|
||||
Loading…
Reference in a new issue