Visual xAgentBuilder^® 9 for C++

Failed to initialize transport. Reason: Winsock error 10048 (WSAEADDRINUSE)?

Visual MIBrowser^®

Visual MIBuilder^®

Visual xAgentBuilder^® 9 for C++

You can easily reference your MIB instrumentation “C” code from within our C++ wizard generated code.  Though a little trickier, you can also reference our C++ interfaces from within your “C” code.

For referencing your “C” code, for example to determine a value for a ‘GET’, you link your code with ours and refer to the function or variable as you normally would from “C”.  In some compilers and environments, you may need prefix the “C” name with double colons (“::”).  For example if a “C” function name is “getMeAValue()”, then you may need to reference it as “::getMeAValue()”.  In all C++ environments, this notation should be permitted so it’s probably advisable just to always use it.

For referring to our code from within “C” you need to create a “C” callable API function on a case by case basis, to reference whatever is required in our code (for example Persistent Storage), from a small C++ module.  The “C” callable function simply needs to be declared from within a special “extern” construct for doing so.  An example of the construct is as follows….

extern “C” {

/*
a small interface function
*/
int performNudesignCall1 ( int param1 )
{

int retVal;
// access NuDesign C++ code here…
retVal = YYYYY.XXXXX();
// where XXXXX is the name of the NuDesign method
// and YYYYY is a object instance.
return retVal;

}

}

From within your “C” code, you’d just call the performNudesignCall1() function as required.

• First, recognize that the wizard produces subagents and that from a single (or multiple) MIB(s), multiple subagents can be produced and loaded into the “master” agent.  Typically subagents are created by selecting various branches within the MIB that represent different areas of instrumentation and producing a subagent to handle each.  By partitioning the agent, it minimizes the likelihood that a change in one subagent will affect another subagent.  Similarly if a new branch is added to the MIB, a new subagent project can be created for it without affecting existing project, incorporating it into the product at the link phase for a static subagent or at load time with a dynamic subagent.
• As each new project is created, place the generated code for each subagent under a revision control system.  If a change is required to the code, the difference analysis tool from the revision control software gives a clear view of what differences the newly generated code have introduced, so that this may be applied to the development project.  You’ll find that with even limited experience with the code produced and given the highly structure nature of the code, you’ll quickly be able to work through changes introduced by a MIB change manually.
• We recommend that you define a software interface layer from our code to your instrumentation code.  The interface could be designed so that it is limited to perhaps a single method call from each of OnGet or OnSet methods, to your code.  This way if a new sub agent needs to be generated, the impact will be limited to cutting and pasting a single method call in each of our methods.  This is particularly helpful when implementing the same agent on multiple platforms where instrumentation is liable to be platform specific.  In essence, you can create platform specific “libraries” of instrumentation, with the core agent code remaining the same for all platforms.

The primary goal of our tools is to get development underway with a minimum of delay due to learning curve issues and to minimize the time introduced to a project by performing time consuming, error prone activities.  In our experience learning curve for a new technology can be a lengthy process with many SNMP development technologies, particularly when multiple platform support is a requirement, since each platform often involves learning about different SNMP development technologies.  Out product spans multiple platforms and the generated code and technology is the same for each platform.

        int err = transport.Initialize(161);

with:

        BAddress addr[2];
        tUint8 teType[2];

        BAddrINet inetAddr;
        inetAddr.SetPort(161);
        addr[0] = inetAddr;
        teType[0] = TETYPE_RECV;

        addr[1].SetFamily(ADDRESS_FAMILY_INET);
        teType[1] = TETYPE_SEND;

        int err = udpTransport.Initialize(addr, teType, 2);

The xAgentBuilder created, standalone agent, defines an instance of the BUdpTransport class, transport, as follows :

BUdpTransport transport;

When not specified, the first parameter for the BUdpTransport constructor is “int maxMsgSize” which has a default value of 2048.

In order to set a new maximum message size, the user could specify a parameter instead.

For example:

BUdpTransport transport(8192);

creates a BUdpTransport transport object which will support a maximum message size of 8KB.

The Initialize method of the BUdpTransport class will adjust the size specified in the constructor to the maximum message size supported by WinSock if that value is lower. For example, if you specify 100000 as the parameter to the constructor, after the Initialize method is called, the actual maximum message size will be set to 65535 which is the maximum message size supported by Winsock.

To check the maximum message size, call the GetMaxMsgSize method. Note that GetMaxMsgSize returns ZERO when called before Initialize method is successfully executed.

BFileNV nvParams(“<project-name>.XNV”);

The agent (through the nvParams objects) will open the file in the current working directory. If it is missing, an empty one was created. An empty configuration file implies that the agent should drop any packet received.  xAgentBuilder generates the .XNV file with a default configuration and places it in the project directory.  Copy that file into the same directory as your executable, or make a change in the line above to point to the correct location of the file.

Also, note that when you shutdown the agent (by entering “q” at the prompt) it saves the current configuration to the file. Make sure to stop the agent before copying this file from the project directory to the directory where your executable resides.

Failed to initialize transport. Reason: Winsock error 10048 (WSAEADDRINUSE)?

BUdpTransport transport;
int err = transport.Initialize(161);
if (err != X_NO_ERROR)
{

cout << “Failed to initialize transport. Reason: ” <<

transport.GetLastError() << endl;

exit(-1);

}

As you can see, the generated agent will try to listen on port 161.  If the another application (probably another SNMP agent) is already using that port, the Initialize method of the BUdpTransport will fail and the above message will be printed.

Here is the example. Assume that SNMP entity has commandResponder and notificationReceiver.  It does not have any request generating subsystem (cmdGenerator, or notifOriginator or proxyForwarder).  User wants to dedicate 161 to cmdResponder and 162 to notifReceiver.

BUdpTransport transport;

tUint16 port[2] = { 161, 162 };
>tUint8 teType[2] = { TETYPE_CMDRESP, TETYPE_NOTIFRECV };
<br
// [0] 161, TETYPE_CMDRESP, -> messages received on this port
// will be passed to cmdResponder
// [1] 162, TETYPE_NOTIFRECV, -> messages received on this
// port will be passed to notifReceiver

transport.Initialize(port, teType, 2);

// NOTE: no socket will be created for outgoing messages

agent->notifOrig.Notify(eSNMPv1Trap_ColdStart);

As you can see, a single line is enough to perform the notification sending operation.  But where the traps will be sent?  The answer lies in configuration tables.  Please consult Lessons 7 and 9 in the Tutorials in xAgentBuilder’s help for the examples.

Here is an example; it sends a cold start v1Trap to “127.0.0.1:162” (assume the agent is an instance of the BSnmpAgent class):

BAddrINet addr;
addr.AssignFromDottedDecimalStr(“127.0.0.1:162”);
BTarget target(addr, “public”, 3, 1);

Agent.notifOrig.SendGenericTrapV1(target, eSNMPv1Trap_ColdStart);

After you upgrade your Visual C++, you can either reinstall xAgentBuilder, or simply copy NDxAB3.awx and NDxAB3.hlp files to the following directory:

%VISUAL-STUDIO-DIR%\Common\MSDev98\Template

where %VISUAL-STUDIO-DIR% is usually:

c:\Program Files\Miscrosoft Visual Studio

In our implementation, we actually implement both sets of objects, but the obsolete objects are only available if the agent has been configured to run in V1 only.  I.e. If the agent is configured to run in v2 and or v3 the obsolete objects appear to be not implemented.

You could modify this behavior if you wish, though it’s not recommended.  It should be a relatively straight forward modification as all the code changes should occur in
BSnmpAgentMibImpl::HandlerAt()
in the module SnmpAgent.cpp in the NDSnmp library.

Visual MIBrowser^®

You can also save multiple queries into a single “query group”.  Saving to a query group is similar to saving as query, except there is the extra step of specifying a query group name after you’ve provided a query name.  You initiate the save to group process by selecting the “File | Save Query to Group” menu option.  You can reload the “Query Group” by selecting the “File | Load Query Group” menu item.  Note: You can also manually edit “Query Group” (.NDG files) from “Edit | Query Group”)

Lastly, you can load queries or query groups from the command line.  This leads to the possibility of creating different “short cuts” for operationally different configurations of MIBrowser.  To create a short cut to MIBrowser, right click anywhere on you windows desktop and select “New | Shortcut”.  Browse to where MIBrowser was installed, select MIBrowser.exe and press “Open”.  On the resulting command line (outside the quotes) type in the path to a query or group file.  Give the Shortcut a meaningful name and press the “Finish” button.  An example command line for the shortcut may look like:

“C:\Program Files\NuDesign Tools\Visual MIBrowser\MIBrowser.exe” setup1.ndg

This would invoke the set of queries that are contained in “setup1.ndg”.  (Note: the “Start in:” entry of the short cut should specify the directory path in which setup1.ndg resides.)

There are several other options available for the command line to affect the format of MIBrowser when it is executed.  These are documented in “Help”, in the “MIBrowser Command Line Interface” section.

Note: You may have simultaneous Chart windows, detecting multiple alarm conditions on different agents.

Visual MIBuilder^®