[Solved] Registry (Hex or int) to ip Address?
lazarus / 34-Windows

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TheLastCayen · 2021-11-15 16:31

I am using

Lazarus 2.0.12
FPC 3.2.0
Windows 10

I need to read an IP Address from the registry. The IP has been
written per a 3rd party software and it's part of that software
configuration.

As an example, the value from the registry is:

1E32A8C0

1E = 30
32 = 50
A8 = 168
C0 = 192

So the ip address is 192.168.50.30 (not sure why they saved it in this
order, probably a pile)
If I read the number as an integer, the value is 506636480.

From there, I am totally lost. It seems easier to use the Hex value in
order to extract my ip and I know I can "Registry.ReadInteger", then
convert using IntToHex((X), );. fpc don't seem really friendly to work
with Hex value. I am not sure how to isolate the number in pair of 2
so I can get the ip address per section. I am not sure how to work
with the decimal version either. I don't see any hex variable I can
work with and I am not too familiar with pointers. 

Anyone can recommend a way to read this ip address or some
documentation to  point me in the right direction?

Thank you

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MarkMLl · 2021-11-15 16:43

So it looks as though it's stored as a little-endian (i.e. x86 native
format) 32-bit word. Try https://www.freepascal.org/docs-
html/current/rtl/system/ntobe.html etc.

MarkMLl

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winni · 2021-11-15 17:09

Hi!

IP addresses in the Windows registry are from the type REG_SZ whichs
is a zero terminated string.

So you should not look for integers/Dwords but for strings with 3 dots
in it.

Winni

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Bart · 2021-11-15 17:17

From your example it looks like you need to parse is as (pseudocode).
Lo(LoWord(Value)) . Hi(LoWord(Value)) . Lo(HiWord(Value)) .
Hi(HiWordValue))
This would give you (Value=1E32A8C0): 192.168.50.30

Bart

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wp · 2021-11-15 17:27

This is a simple converter:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i function
IPAddressFromInteger(x: LongInt): String;type  TIPAddress = packed
record b1, b2, b3, b4: byte; end;begin  with TIPAddress(x) do   
Result := Format('%d.%d.%d.%d', [b1, b2, b3, b4]);end;

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Remy Lebeau · 2021-11-15 18:01

Quote from: winni on November 15, 2021, 06:09:56 pmIP addresses in the
Windows registry are from the type REG_SZ whichs is a zero terminated
string.

Clearly, the Registry value in question is not stored in REG_SZ
format, but in REG_DWORD or REG_BINARY format, otherwise this wouldn't
even be an issue.

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TheLastCayen · 2021-11-15 23:07

Thank you everyone for your quick answer.

wp function fixed my puzzle