@echo off
setlocal

rem read or set IPoIB-CM registry values.

rem If %2 value is supplied, then the RegKey operation is 'set', otherwise 'read'. 

if "%1" == "/?"  (
:usage
	echo read/set IPoIB-CM registry values
	echo usage: cm reg-key {value}
	echo. 
	echo example: cm CmPayloadMtu 4096 
	echo example: cm CmEnabled 1
	exit /B 1
)
if "%1" == ""  goto usage
if "%1" == "-h"  goto usage

set B=%WINDIR%\temp

rem CmEnabled 0/1
rem set K=CmPayloadMtu
rem set V=4096

set K=%1
set V=%2

if "%2" == "" (
	echo %COMPUTERNAME% reading IPoIB-CM reg Key %K%
) else (
	echo %COMPUTERNAME% setting IPoIB-CM reg Key %K% value %V%
)

set H=HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1-08002BE10318}

if exist  del /Q %B%\foo.txt

reg query %H% > %B%\foo.txt
if ERRORLEVEL 1  (
	echo ERR - reg query %H% ?
	echo Check %B%\foo.txt for error conditions.
	exit /B 1
)

for /f %%i in (%B%\foo.txt) do (
	reg query %%i\ /v %K% > Nul 2>&1
	if !ERRORLEVEL! EQU 0 (
		if "%2" == "" (
			reg query %%i\ /v %K%
		) else (
			reg add %%i\ /v %K% /t REG_SZ /d %V% /f
		)
	)
)
if exist  del /Q %B%\foo.txt
endlocal