Datatype for storing ip address in SQL Server

Here is some code to convert either IPV4 or IPv6 in varchar format to binary(16) and back. This is the smallest form I could think of. It should index well and provide a relatively easy way to filter on subnets. Requires SQL Server 2005 or later. Not sure it's totally bulletproof. Hope this helps.

-- SELECT dbo.fn_ConvertIpAddressToBinary('2002:1ff:6c2::1ff:6c2')
-- SELECT dbo.fn_ConvertIpAddressToBinary('10.4.46.2')
-- SELECT dbo.fn_ConvertIpAddressToBinary('bogus')

ALTER FUNCTION dbo.fn_ConvertIpAddressToBinary
(
     @ipAddress VARCHAR(39)
)
RETURNS BINARY(16) AS
BEGIN
DECLARE
     @bytes BINARY(16), @vbytes VARBINARY(16), @vbzone VARBINARY(2)
     , @colIndex TINYINT, @prevColIndex TINYINT, @parts TINYINT, @limit TINYINT
     , @delim CHAR(1), @token VARCHAR(4), @zone VARCHAR(4)

SELECT
     @delim = '.'
     , @prevColIndex = 0
     , @limit = 4
     , @vbytes = 0x
     , @parts = 0
     , @colIndex = CHARINDEX(@delim, @ipAddress)

IF @colIndex = 0
     BEGIN
           SELECT
                @delim = ':'
                , @limit = 8
                , @colIndex = CHARINDEX(@delim, @ipAddress)
           WHILE @colIndex > 0
                SELECT
                      @parts = @parts + 1
                      , @colIndex = CHARINDEX(@delim, @ipAddress, @colIndex + 1)
           SET @colIndex = CHARINDEX(@delim, @ipAddress)

           IF @colIndex = 0
                RETURN NULL     
     END

SET @ipAddress = @ipAddress + @delim

WHILE @colIndex > 0
     BEGIN
           SET @token = SUBSTRING(@ipAddress, @prevColIndex + 1, @Colindex - @prevColIndex - 1)

           IF @delim = ':'
                BEGIN
                      SET  @zone = RIGHT('0000' + @token, 4)

                      SELECT
                           @vbzone = CAST('' AS XML).value('xs:hexBinary(sql:variable("@zone"))', 'varbinary(2)')
                           , @vbytes = @vbytes + @vbzone

                      IF @token = ''
                           WHILE @parts + 1 < @limit
                                 SELECT
                                      @vbytes = @vbytes + @vbzone
                                      , @parts = @parts + 1
                END
           ELSE
                BEGIN
                      SET @zone = SUBSTRING('' + master.sys.fn_varbintohexstr(CAST(@token AS TINYINT)), 3, 2)

                      SELECT
                           @vbzone = CAST('' AS XML).value('xs:hexBinary(sql:variable("@zone"))', 'varbinary(1)')
                           , @vbytes = @vbytes + @vbzone
                END

           SELECT
                @prevColIndex = @colIndex
                , @colIndex = CHARINDEX(@delim, @ipAddress, @colIndex + 1) 
     END            

SET @bytes =
     CASE @delim
           WHEN ':' THEN @vbytes
           ELSE 0x000000000000000000000000 + @vbytes
     END 

RETURN @bytes

END
-- SELECT dbo.fn_ConvertBinaryToIpAddress(0x200201FF06C200000000000001FF06C2)
-- SELECT dbo.fn_ConvertBinaryToIpAddress(0x0000000000000000000000000A0118FF)

ALTER FUNCTION [dbo].[fn_ConvertBinaryToIpAddress]
(
     @bytes BINARY(16)
)
RETURNS VARCHAR(39) AS
BEGIN
DECLARE
     @part VARBINARY(2)
     , @colIndex TINYINT
     , @ipAddress VARCHAR(39)

SET @ipAddress = ''

IF SUBSTRING(@bytes, 1, 12) = 0x000000000000000000000000
     BEGIN
           SET @colIndex = 13
           WHILE @colIndex <= 16
                SELECT
                      @part = SUBSTRING(@bytes, @colIndex, 1)
                      , @ipAddress = @ipAddress
                           + CAST(CAST(@part AS TINYINT) AS VARCHAR(3))
                           + CASE @colIndex WHEN 16 THEN '' ELSE '.' END
                      , @colIndex = @colIndex + 1

           IF @ipAddress = '0.0.0.1'
                SET @ipAddress = '::1'
     END
ELSE
     BEGIN
           SET @colIndex = 1
           WHILE @colIndex <= 16
                BEGIN
                      SET @part = SUBSTRING(@bytes, @colIndex, 2)
                      SELECT
                           @ipAddress = @ipAddress
                                 + CAST('' as xml).value('xs:hexBinary(sql:variable("@part") )', 'varchar(4)')
                                 + CASE @colIndex WHEN 15 THEN '' ELSE ':' END
                           , @colIndex = @colIndex + 2
                END
     END

RETURN @ipAddress   

END 

You can use varchar. The length of IPv4 is static, but that of IPv6 may be highly variable.

Unless you have a good reason to store it as binary, stick with a string (textual) type.


The technically correct way to store IPv4 is binary(4), since that is what it actually is (no, not even an INT32/INT(4), the numeric textual form that we all know and love (255.255.255.255) being just the display conversion of its binary content).

If you do it this way, you will want functions to convert to and from the textual-display format:

Here's how to convert the textual display form to binary:

CREATE FUNCTION dbo.fnBinaryIPv4(@ip AS VARCHAR(15)) RETURNS BINARY(4)
AS
BEGIN
    DECLARE @bin AS BINARY(4)

    SELECT @bin = CAST( CAST( PARSENAME( @ip, 4 ) AS INTEGER) AS BINARY(1))
                + CAST( CAST( PARSENAME( @ip, 3 ) AS INTEGER) AS BINARY(1))
                + CAST( CAST( PARSENAME( @ip, 2 ) AS INTEGER) AS BINARY(1))
                + CAST( CAST( PARSENAME( @ip, 1 ) AS INTEGER) AS BINARY(1))

    RETURN @bin
END
go

And here's how to convert the binary back to the textual display form:

CREATE FUNCTION dbo.fnDisplayIPv4(@ip AS BINARY(4)) RETURNS VARCHAR(15)
AS
BEGIN
    DECLARE @str AS VARCHAR(15) 

    SELECT @str = CAST( CAST( SUBSTRING( @ip, 1, 1) AS INTEGER) AS VARCHAR(3) ) + '.'
                + CAST( CAST( SUBSTRING( @ip, 2, 1) AS INTEGER) AS VARCHAR(3) ) + '.'
                + CAST( CAST( SUBSTRING( @ip, 3, 1) AS INTEGER) AS VARCHAR(3) ) + '.'
                + CAST( CAST( SUBSTRING( @ip, 4, 1) AS INTEGER) AS VARCHAR(3) );

    RETURN @str
END;
go

Here's a demo of how to use them:

SELECT dbo.fnBinaryIPv4('192.65.68.201')
--should return 0xC04144C9
go

SELECT dbo.fnDisplayIPv4( 0xC04144C9 )
-- should return '192.65.68.201'
go

Finally, when doing lookups and compares, always use the binary form if you want to be able to leverage your indexes.


UPDATE:

I wanted to add that one way to address the inherent performance problems of scalar UDFs in SQL Server, but still retain the code-reuse of a function is to use an iTVF (inline table-valued function) instead. Here's how the first function above (string to binary) can be re-written as an iTVF:

CREATE FUNCTION dbo.itvfBinaryIPv4(@ip AS VARCHAR(15)) RETURNS TABLE
AS RETURN (
    SELECT CAST(
               CAST( CAST( PARSENAME( @ip, 4 ) AS INTEGER) AS BINARY(1))
            +  CAST( CAST( PARSENAME( @ip, 3 ) AS INTEGER) AS BINARY(1))
            +  CAST( CAST( PARSENAME( @ip, 2 ) AS INTEGER) AS BINARY(1))
            +  CAST( CAST( PARSENAME( @ip, 1 ) AS INTEGER) AS BINARY(1))
                AS BINARY(4)) As bin
        )
go

Here's it in the example:

SELECT bin FROM dbo.fnBinaryIPv4('192.65.68.201')
--should return 0xC04144C9
go

And here's how you would use it in an INSERT

INSERT INTo myIpTable
SELECT {other_column_values,...},
       (SELECT bin FROM dbo.itvfBinaryIPv4('192.65.68.201'))