New-IPSubnet.ps1

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
<#PSScriptInfo
 
    .VERSION 1.0.2
 
    .GUID 3bb10ee7-38c1-41b9-88ea-16899164fc19
 
    .AUTHOR Anthony J. Raymond
 
    .COMPANYNAME
 
    .COPYRIGHT (c) 2022 Anthony J. Raymond
 
    .TAGS IP Subnet Network IPv4 IPv6
 
    .LICENSEURI https://github.com/CodeAJGit/posh/blob/main/LICENSE
 
    .PROJECTURI https://github.com/CodeAJGit/posh
 
    .ICONURI
 
    .EXTERNALMODULEDEPENDENCIES
 
    .REQUIREDSCRIPTS
 
    .EXTERNALSCRIPTDEPENDENCIES
 
    .RELEASENOTES
        20220302-AJR: v1.0.0 - Initial Release
        20220302-AJR: v1.0.1 - Fix Clerical Errors and Added Tags
        20220305-AJR: v1.0.2 - Updated Metadata
 
    .PRIVATEDATA
 
#>


<#
 
    .DESCRIPTION
        Creates an [IPSubnet] object for use to manipulate IPv4 & IPv6 subnets.
 
    .EXAMPLE
        .\New-IPSubnet.ps1 192.168.1.0/30
 
    .EXAMPLE
        .\New-IPSubnet.ps1 -Subnet 2001:db8::1 -Prefix 32
 
    .PARAMETER Subnet
        Specifies an IPv4 or IPv6 address.
 
    .PARAMETER Prefix
        <Optional> Specifies the prefix (or network portion) of the address.
 
#>

[CmdletBinding()]
[OutputType([object])]

## PARAMETERS #############################################################
param (
    [Parameter(
        Position = 0,
        Mandatory
    )]
    [string]
    $Subnet,

    [Parameter()]
    [ValidateRange(0, 128)]
    [int]
    $Prefix = ($Subnet -split '\\|\/')[-1]
)

## FUNCTIONS AND SCRIPT VARIABLES #########################################
class IPSubnet : System.Object {
    # class properties ####################################################
    [System.Net.IPAddress] $Network
    [System.Net.Sockets.AddressFamily] $AddressFamily
    [ValidateRange(0, 128)] [int] $Prefix
    [System.Net.IPAddress] $SubnetMask
    [System.Net.IPAddress] $LastAddress

    [bigint] hidden $PrefixInt
    [bigint] hidden $StartInt
    [bigint] hidden $EndInt

    # class methods #######################################################
    [string] ToString() {
        return ("{0}/{1}" -f $this.Network, $this.Prefix)
    }

    [bool] Contains([System.Net.IPAddress]$InputIPAddress) {
        # compute and compare network address
        $InputAddress = $this.ToAddress($InputIPAddress, $false) -band $this.PrefixInt
        $NetworkAddress = $this.ToAddress($this.Network, $false)

        return ($NetworkAddress -eq $InputAddress)
    }

    [IPSubnet[]] Subnet([int]$InputPrefix) {
        $Power = switch ($this.AddressFamily) {
            "InterNetwork" { [bigint]::Pow(2, (32 - $InputPrefix)) }
            "InterNetworkV6" { [bigint]::Pow(2, (128 - $InputPrefix)) }
        }
        $Subnets = for ($AddressInt = $this.StartInt; $AddressInt -le $this.EndInt; $AddressInt += $Power) {
            [IPSubnet]::new(($this.FromAddress($AddressInt, $true)), $InputPrefix)
        }
        return $Subnets
    }

    [bigint] hidden ToAddress([System.Net.IPAddress]$InputIPAddress, [bool]$Reverse) {
        # here we go address -> bytes -> reverse -> bigint
        [byte[]] $Bytes = $InputIPAddress.GetAddressBytes()

        if ($Reverse) {
            [array]::Reverse($Bytes)
        }
        # append zero byte for unsigned
        return [bigint]::new($Bytes + 0)
    }

    [System.Net.IPAddress] hidden FromAddress([bigint]$InputInt, [bool]$Reverse) {
        # here we go backward bigint -> bytes -> reverse -> address
        [byte[]] $Bytes = $InputInt.ToByteArray()

        # we're going to pad the array for the size that the IPAddress constructor expects
        switch ($this.AddressFamily) {
            "InterNetwork" { [array]::Resize([ref]$Bytes, 4) }
            "InterNetworkV6" { [array]::Resize([ref]$Bytes, 16) }
        }
        if ($Reverse) {
            [array]::Reverse($Bytes)
        }
        return ([System.Net.IPAddress] $Bytes)
    }

    [bigint] hidden GetPrefixInt([int]$InputInt) {
        # turn prefix into binary string so we can work with it
        $Binary = switch ($this.AddressFamily) {
            "InterNetwork" { ('1' * $InputInt).PadRight(32, '0') }
            "InterNetworkV6" { ('1' * $InputInt).PadRight(128, '0') }
        }
        # the last element of this match is null, so skip it
        $Octet = $Binary -split '(?<=\G[01]{8})' | Select-Object -SkipLast 1
        $Bytes = $Octet | ForEach-Object { [System.Convert]::ToUInt32($_, 2) }

        # append zero byte for unsigned
        return [bigint]::new($Bytes + 0)
    }

    [void] hidden __init__([System.Net.IPAddress]$InputIPAddress, [int]$InputPrefix) {
        $this.Prefix = $InputPrefix
        $this.AddressFamily = $InputIPAddress.AddressFamily

        # quick prefix validation
        switch ($true) {
            {$this.AddressFamily -eq "InterNetwork" -and $this.Prefix -in 0..32} { break }
            {$this.AddressFamily -eq "InterNetworkV6" -and $this.Prefix -in 0..128} { break }
            default {throw [System.InvalidCastException] "An invalid prefix for the given address family was specified."}
        }
        $this.PrefixInt = $this.GetPrefixInt($this.Prefix)
        $this.SubnetMask = $this.FromAddress($this.PrefixInt, $false)

        # using the prefix we can find the network address
        $StartAddress = $this.ToAddress($InputIPAddress, $false) -band $this.PrefixInt
        $this.Network = $this.FromAddress($StartAddress, $false)

        # using the prefix, we can find the last address
        $EndAddress = switch ($this.AddressFamily) {
            "InterNetwork" { $StartAddress -bor (-bnot $this.PrefixInt -band ([bigint]::Pow(2, 32) -1)) }
            "InterNetworkV6" { $StartAddress -bor (-bnot $this.PrefixInt -band ([bigint]::Pow(2, 128) -1)) }
        }
        $this.LastAddress = $this.FromAddress($EndAddress, $false)

        $this.StartInt = $this.ToAddress($this.Network, $true)
        $this.EndInt = $this.ToAddress($this.LastAddress, $true)

        Update-TypeData -TypeName IPSubnet -MemberType AliasProperty -MemberName Broadcast -Value LastAddress -Force
        Update-TypeData -TypeName IPSubnet -MemberType AliasProperty -MemberName Mask -Value SubnetMask -Force
        Update-TypeData -TypeName IPSubnet -DefaultDisplayPropertySet Network, AddressFamily, Prefix, LastAddress -Force
    }

    # class constructors ##################################################
    IPSubnet([System.Net.IPAddress]$InputIPAddress, [int]$InputPrefix) {
        $this.__init__($InputIPAddress, $InputPrefix)
    }

    IPSubnet([string]$InputString) {
        try {
            $SplitString = $InputString -split '\\|\/'
            [System.Net.IPAddress] $InputIPAddress = $SplitString[0]
            [int] $InputPrefix = $SplitString[-1]
        }
        catch {
            throw [System.InvalidCastException] "An invalid IP address or prefix format was specified."
        }
        $this.__init__($InputIPAddress, $InputPrefix)
    }
}

## EXECUTION ##############################################################
[IPSubnet]::new(($Subnet -split '\\|\/')[0], $Prefix)

## CLEAN UP ###############################################################
[void]([System.GC]::GetTotalMemory($true))