Question

我想检查IP地址是否在最小和最大IP地址范围内。我怎么能在Delphi中做到这一点？

例如，我想做这样的事情：

if CheckIp("127.0.0.15","127.0.0.1","127.0.0.255") then ShowMessage('ok');

127.0.0.1是范围的起始值，127.0.0.255是范围的结束值，127.0.0.15是要检查的IP地址。

Answer 1

对于IPv4地址，您只需将它们转换为整数形式，然后对它们执行标准序数比较。

IPv6地址太大而无法转换为整数（除非您使用第三方BigInt库），因此您必须将它们转换为二进制形式，然后逐字节地比较它们。

Answer 2

我将假设您的地址是以主机字节顺序存储在32位整数中的IPv4地址。而且我还假设你想要一个词典排序，以便：

 a.b.c.d < p.q.r.s

首先比较a和p进行比较，如果相等，则比较b和q，依此类推。

在这种情况下，自然无符号整数排序（使用<或>运算符）将产生您想要的排序。

如果地址按网络字节顺序排列，则需要在比较之前转换为主机字节顺序。

在您的问题中，您将地址作为字符串。因此，您需要将它们转换为具有inet_addr的网络字节顺序32位无符号整数，然后使用ntohl将字节顺序转换为主机。然后你可以比较。

Answer 3

之前我曾在a slightly similar question询问过IP地址的一般字符串例程。基于the answer by NGLN，我实现了一组比较函数和一个演示应用程序。函数IPRange检测它是v4还是v6并相应地进行比较。

<强> uMain.pas

unit uMain;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls,
  IPTypes;

type
  TfrmCheckIPRange = class(TForm)
    txtFrom: TEdit;
    txtTo: TEdit;
    txtIP: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    txtResult: TEdit;
    Label4: TLabel;
    procedure DoCheck(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  frmCheckIPRange: TfrmCheckIPRange;

implementation

{$R *.dfm}

function IntRange(const Val, Min, Max: Integer): Boolean;
begin
  Result:= (Val >= Min) and (Val <= Max);
end;

function IPRangeV4(const IP, IPFrom, IPTo: TIPv4): Boolean;
begin
  Result:= IntRange(IP.D, IPFrom.D, IPTo.D);
  if Result then
    Result:= IntRange(IP.C, IPFrom.C, IPTo.C);
    if Result then
      Result:= IntRange(IP.B, IPFrom.B, IPTo.B);
      if Result then
        Result:= IntRange(IP.A, IPFrom.A, IPTo.A);
end;

function IPRangeV6(const IP, IPFrom, IPTo: TIPv6): Boolean;
begin
  Result:= IntRange(IP.H, IPFrom.H, IPTo.H);
  if Result then
    Result:= IntRange(IP.G, IPFrom.G, IPTo.G);
    if Result then
      Result:= IntRange(IP.F, IPFrom.F, IPTo.F);
      if Result then
        Result:= IntRange(IP.E, IPFrom.E, IPTo.E);
        if Result then
          Result:= IntRange(IP.D, IPFrom.D, IPTo.D);
          if Result then
            Result:= IntRange(IP.C, IPFrom.C, IPTo.C);
            if Result then
              Result:= IntRange(IP.B, IPFrom.B, IPTo.B);
              if Result then
                Result:= IntRange(IP.A, IPFrom.A, IPTo.A);
end;

function IPRange(const IP, IPFrom, IPTo: String): Boolean;
var
  IP4, FR4, TO4: TIPv4;
  IP6, FR6, TO6: TIPv6;
  function IsV4(const S: String): Boolean;
  begin
    Result:= Pos('.', S) > 1;
  end;
  function IsV6(const S: String): Boolean;
  begin
    Result:= Pos(':', S) > 0;
  end;
begin
  Result:= False;
  if (IsV6(IP)) and (IsV6(IPFrom)) and (IsV6(IPTo)) then begin
    IP6:= StrToIPv6(IP);
    FR6:= StrToIPv6(IPFrom);
    TO6:= StrToIPv6(IPTo);
    Result:= IPRangeV6(IP6, FR6, TO6);
  end else
  if (IsV4(IP)) and (IsV4(IPFrom)) and (IsV4(IPTo)) then begin
    IP4:= StrToIPv4(IP);
    FR4:= StrToIPv4(IPFrom);
    TO4:= StrToIPv4(IPTo);
    Result:= IPRangeV4(IP4, FR4, TO4);
  end else begin
    raise Exception.Create('Invalid IP Address Input');
  end;
end;

{ TfrmCheckIPRange }

procedure TfrmCheckIPRange.FormCreate(Sender: TObject);
begin
  DoCheck(nil);
end;

procedure TfrmCheckIPRange.DoCheck(Sender: TObject);
begin
  try
    if IPRange(txtIP.Text, txtFrom.Text, txtTo.Text) then begin
      txtResult.Text:= 'IP is in range';
      txtResult.Color:= clGreen;
    end else begin
      txtResult.Text:= 'IP is NOT in range';
      txtResult.Color:= clRed;
    end;
  except
    on e: exception do begin
      txtResult.Text:= e.Message;
      txtResult.Color:= clYellow;
    end;
  end;
end;

end.

<强> uMain.dfm

object frmCheckIPRange: TfrmCheckIPRange
  Left = 350
  Top = 113
  BorderIcons = [biSystemMenu]
  BorderStyle = bsSingle
  Caption = 'Check IP Range'
  ClientHeight = 124
  ClientWidth = 296
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poScreenCenter
  OnCreate = FormCreate
  DesignSize = (
    296
    124)
  PixelsPerInch = 96
  TextHeight = 13
  object Label1: TLabel
    Left = 11
    Top = 11
    Width = 71
    Height = 13
    Alignment = taRightJustify
    Caption = 'IP To Compare'
  end
  object Label2: TLabel
    Left = 11
    Top = 38
    Width = 71
    Height = 13
    Alignment = taRightJustify
    Caption = 'IP Range From'
  end
  object Label3: TLabel
    Left = 23
    Top = 65
    Width = 59
    Height = 13
    Alignment = taRightJustify
    Caption = 'IP Range To'
  end
  object Label4: TLabel
    Left = 52
    Top = 92
    Width = 30
    Height = 13
    Alignment = taRightJustify
    Caption = 'Result'
  end
  object txtFrom: TEdit
    Left = 88
    Top = 35
    Width = 196
    Height = 21
    Anchors = [akLeft, akTop, akRight]
    TabOrder = 1
    Text = '192.168.3.100'
    OnChange = DoCheck
    ExplicitWidth = 158
  end
  object txtTo: TEdit
    Left = 88
    Top = 62
    Width = 196
    Height = 21
    Anchors = [akLeft, akTop, akRight]
    TabOrder = 2
    Text = '192.168.3.200'
    OnChange = DoCheck
    ExplicitWidth = 158
  end
  object txtIP: TEdit
    Left = 88
    Top = 8
    Width = 196
    Height = 21
    Anchors = [akLeft, akTop, akRight]
    TabOrder = 0
    Text = '192.168.3.105'
    OnChange = DoCheck
    ExplicitWidth = 158
  end
  object txtResult: TEdit
    Left = 88
    Top = 89
    Width = 196
    Height = 21
    Anchors = [akLeft, akTop, akRight]
    Font.Charset = DEFAULT_CHARSET
    Font.Color = clWindowText
    Font.Height = -11
    Font.Name = 'Tahoma'
    Font.Style = [fsBold]
    ParentFont = False
    ReadOnly = True
    TabOrder = 3
    OnChange = DoCheck
    ExplicitWidth = 158
  end
end

我已经测试了IPv4，但没有测试过IPv6，尽管它应该可行。我对IPv6知之甚少，甚至不知道不同的测试场景。

您可能还想添加一些逻辑来检查IP是否在同一子网内，因为您可能不想包含不同的子网。这就像确保前3个数字（v4）完全相同一样容易。如果子网存在任何差异，您可能希望引发异常，但这完全取决于您需要如何实现这一点。

修改

我在确定v4 vs v6时修复了逻辑，因为IPv6地址也可能包含.，我必须将检查顺序从v4-v6切换到v6-v4。

如何在Delphi中检查IP地址是否在两个IP的范围内？

3 个答案: