问题
Ok, it's friday afternoon, and i've had a long week so would appreciate some help! Currently, i have a list of IP ranges, as follows:
List<IPRange> ipRanges = new List<IPRange>();
ipRanges.Add(new IPRange { From = "145.36.0.0", To = "145.36.255.255" });
ipRanges.Add(new IPRange { From = "194.183.227.184", To = "194.183.227.191" });
ipRanges.Add(new IPRange { From = "193.131.192.0", To = "193.131.223.255" });
After getting the IP of the client, if it falls anywhere between these sets of ranges, they need to be redirected elsewhere.
For example,
If someone visited the site with the IP 192.168.0.1, they would be allowed access.
If they visited with 145.36.1.0, they would not be allowed access because it falls between the first range in that list.
I could split each IP by the period, and work out where the range starts to change, then do a comparison, but that would be heavy on the server.
I know IP's are basically just decimal numbers, but am not really sure how that works.
Has anyone come across this before?
Cheers, Sean.
回答1:
Convert Each IP-address to number, and then check if the user ip address is between those numbers.
public double Dot2LongIP(string DottedIP)
{
int i;
string [] arrDec;
double num = 0;
if (DottedIP == "")
{
return 0;
}
else
{
arrDec = DottedIP.Split('.');
for(i = arrDec.Length - 1; i >= 0 ; i --)
{
num += ((int.Parse(arrDec[i])%256) * Math.Pow(256 ,(3 - i )));
}
return num;
}
}
回答2:
I would convert the IP addresses to 32-bit numbers and then do a simple >= From and <= To check to see if it's in range.
For example, 192.168.1.1 -> 192 * 256^3 + 168 * 256^2 + 1 * 256 + 1.
Working with your values, 145.36.0.0 -> 2435055616 and 145.36.0.0 -> 2435121151. So 145.36.200.30 -> 2435106846, and falls in that range, so it's valid. But 145.35.255.255 -> 2435055615 is not in the range (just barely), so it fails.
回答3:
I would write my IPRange class so that the getter/setters internally convert the IP string to a number:
new IPRange { From = "145.36.0.0", To = "145.36.255.255" }
Would internally set:
int from = 145036000000;
int to = 145036255255;
Then add a .IsInRange(string ip) method that converts the incoming IP to the name int form and does a plain comparison.
public bool IsInRange(string ipStr)
{
int ip = ConvertIPStringToInt(ipStr);
return (from <= ip && ip <= to);
}
That way you dont have to split the IPs in the range by periods each time its checked.
回答4:
Just for fun (and some semblance of completeness) - the other way obvious to do this is to ensure that you always use 3 digits for each segment of the IP address when stored as a string i.e. 145.36.0.0 should be 145.036.000.000 - that way the strings would be directly comparable.
And the Less obvious would be to have an explicit IP Address class and a roll your own set of comparison logic (I'm rashly assuming that there isn't already something like this buried in the depths of the .NET framework...)
回答5:
I read about this a few days ago.
You can get your IP ranges converted and compare.
IF exists (SELECT * from dbo.sysobjects
WHERE id = object_id(N'[dbo].[IsPrivateIP]')
AND OBJECTPROPERTY(id, N'IsScalarFunction') = 1)
DROP FUNCTION [dbo].[IsPrivateIP]
GO
CREATE FUNCTION dbo.IsPrivateIP( @vcIPAddress varchar(15))
/**************************************************************************
DESCRIPTION: Returns Numeric IP if not private, otherwise returns null
PARAMETERS:
@vcIPAddress - The string containing a valid IP
RETURNS: IP converted to bigint or null if a private IP
USAGE: SELECT dbo.IsPrivateIP( '207.158.26.10')
DEPENDANCIES: dbo.IPStringToNumber() function
AUTHOR: Karen Gayda
DATE: 06/11/2003
MODIFICATION HISTORY:
WHO DATE DESCRIPTION
--- ---------- ---------------------------------------------------
***************************************************************************/
RETURNS bigint
AS
BEGIN
DECLARE @biClassALo bigint ,
@biClassAHi bigint ,
@biClassBLo bigint ,
@biClassBHi bigint ,
@biClassCLo bigint ,
@biClassCHi bigint ,
@biIP bigint,
@bTemp int
SET @biClassALo = 167772160
SET @biClassAHi = 169549375
SET @biClassBLo = 2885681152
SET @biClassBHi = 2887778303
SET @biClassCLo = 3232235520
SET @biClassCHi = 3232301055
SET @biIP = dbo.IPStringToNumber(@vcIPAddress)
IF @biIP BETWEEN @biClassALo AND @biClassAHi OR @biIP BETWEEN @biClassBLo AND @biClassBHi
OR @biIP BETWEEN @biClassCLo AND @biClassCHi
SET @biIP = NULL
RETURN @biIP
END
GO
Here is the IPStringToNumber function that it needs:
IF exists (SELECT * from dbo.sysobjects
WHERE id = object_id(N'[dbo].[IPStringToNumber]')
AND OBJECTPROPERTY(id, N'IsScalarFunction') = 1)
DROP FUNCTION [dbo].[IPStringToNumber]
GO
CREATE FUNCTION dbo.IPStringToNumber( @vcIPAddress varchar(15))
/**************************************************************************
DESCRIPTION: Returns Numeric IP, otherwise returns null
PARAMETERS:
@vcIPAddress - The string containing a valid IP
RETURNS: IP converted to bigint or null if not a valid IP
USAGE: SELECT dbo.IPStringToNumber( '10.255.255.255')
AUTHOR: Karen Gayda
DATE: 06/11/2003
MODIFICATION HISTORY:
WHO DATE DESCRIPTION
--- ---------- ---------------------------------------------------
***************************************************************************/
RETURNS bigint
AS
BEGIN
DECLARE
@biOctetA bigint,
@biOctetB bigint,
@biOctetC bigint,
@biOctetD bigint,
@biIP bigint
DECLARE @tblArray TABLE
(
OctetID smallint, --Array index
Octet bigint --Array element contents
)
--split the IP string and insert each octet into a table row
INSERT INTO @tblArray
SELECT ElementID, Convert(bigint,Element) FROM dbo.Split(@vcIPAddress, '.')
--check that there are four octets and that they are within valid ranges
IF (SELECT COUNT(*) FROM @tblArray WHERE Octet BETWEEN 0 AND 255) = 4
BEGIN
SET @biOctetA = (SELECT (Octet * 256 * 256 * 256) FROM @tblArray WHERE OctetID = 1)
SET @biOctetB = (SELECT (Octet * 256 * 256 ) FROM @tblArray WHERE OctetID = 2)
SET @biOctetC = (SELECT (Octet * 256 ) FROM @tblArray WHERE OctetID = 3)
SET @biOctetD = (SELECT (Octet) FROM @tblArray WHERE OctetID = 4)
SET @biIP = @biOctetA + @biOctetB + @biOctetC + @biOctetD
END
RETURN(@biIP)
END
References:
http://www.sqlservercentral.com/scripts/Miscellaneous/31036/
http://www.sqlservercentral.com/Authors/Scripts/kgayda/17134/
来源：https://stackoverflow.com/questions/1614003/restricting-an-ip-if-it-is-between-an-ip-range