I think this thread became more complicated because - as you can see - fundamentally different suggestions have been offered, e.g. do not use inverted calls, but rather kernel sockets. Now after taking a look at that, I have to agree with you that maybe that is not a simpler approach after all.
I am probably over-thinking this. Serving up pending requests (i.e. inverted call model) does seem like the way to go; also, it should provide the most flexibility - which certainly is not a bad thing!
But you are not able to modify the PDC code, do you ? From what I understood, that is specifically (aside from the 2 features you’ve mentionned) why you are doing all this (the constraints). You will have to open a socket to the PDC anyway ?
How are you going to communicate between your VNIC and the PDC ?
But you are not able to modify the PDC code, do you ?
For this iteration, I will not be modifying the PDC code, i.e. I need to maintain its socket interface and use it as a “block box”.
After posting my initial message to this thread, I came up with a scheme that I think will serve my needs. It involves adding a “shim” user-mode application that employs the inverted calls to exchange data with VNIC component. So now we would have:
Software A (GUI) <-socket-> VNIC <-pending I/O requests-> Software C (shim) <-socket-> Software B (PDC) <--> h/w
I think that allows me to develop iterations while preserving current interfaces.
You’re overcomplicating the issue. You simply want to “proxy” the communication between Soft. A and Soft. B (PDC). Adding a third layer will simply add more requirements and deployments issues.
The inverted call model seems like a bad idea to me but it can be done. It’s a matter of preferences I guess. I agree that Winsock is complicated if you just happen to learn about it. Needs multiple calls and IRP/Stack creation just to setup a simple socket object…
The inverted call model seems like a bad idea to me but it can be done. It’s a matter of preferences I guess.
Unless I misunderstood, I think that that is the method that Peter V. was advocating above.
Eventually both Software A & B components will be modified. But for this iteration:
to demonstrate a VNIC for their use
while maintaining their current interfaces, and
not modifying them
I think what I presented is one approach to get me there.
I appreciate your feedback and suggestions here. Thank you!
This has GOT to be the world’s most confusing, over engineered, thread.
If the idea is to “glue” the output of Software A (which sends data via Sockets) to Software B (which receives data via sockets)… and for some reason they can’t talk directly to each other (hmmm… OK? They talk using different ports or something, I GUESS)… Then, write a user-mode sockets program that gets stuff from A and sends it to B, and your done.
Like I said… I should so stay out of this thread. I just don’t understand any of this.
ETA:
Gad! I’m not insane! I see that Mr. Roberts said exactly this, some days ago:
write a very simple this-to-that that listens on port A and writes to port B? That’s about 10 lines of Python code.
Software A & B do talk to each other, over a socket connection, that is true.
I tried to explain in my initial post to this thread that there is a requirement to insert a VNIC between them while leaving them “as is”. That is the impetus for this thread: how to facilitate that communication.
A “VNIC” that does WHAT, exactly? How do YOU define a VNIC?
How does the proverbial “10 line Python program” logically differ from your definition of a VNIC?
As we so very often say here: “What larger problem are you trying to solve?” Does A send socket traffic to B, which is on a different, pre-defined, IP Address? So, you want this VNIC to fake the IP address?? What is the problem that needs solving here?
A “VNIC” that does WHAT, exactly? How do YOU define a VNIC?
VNIC = Virtual Network Adapter
As we so very often say here: “What larger problem are you trying to solve?” Does A send socket traffic to B, which is on a different, pre-defined, IP Address? So, you want this VNIC to fake the IP address?? What is the problem that needs solving here?
This is part of a larger government contract, so the less I say about “why” the better (if we can just leave it at that, it would be good…)
The requirement (from the powers that be) for the VNIC is to:
provide network interface for Software A
provide network interface for other future software applications
provide ability to bridge disparate network interfaces
It is important to note that the “lower edge” of the VNIC does not interface directly with h/w; it is the user-mode component PDC ( Software B ) that interfaces with h/w devices that go out to their “cloud”.
Also, for this iteration I wanted to keep Software A & B “as is”.
I hope this helps to clarify. Sorry for my earlier vagueness. I think in being careful to not divulge too much I just made things more confusing.
Presumably this is phase 1 in a larger project where you will make further changes? Possibly a new GUI control program is planned and this is some way of allowing both of them to talk to the controller simultaneously or interchangeably?
I have a comment that is pending approval, but yes, this is the first phase of a larger implementation. I want to prototype the approach such that I can leave Software A & B unmodified - for now - and support the requirement (as it is) is to introduce a virtual network component between those 2 user-mode applications. That is the crux of the problem.
to start, a network bridge. Presumably, with more functionality to come? but what kind? they already communicate via a network protocol, so it can’t be remoting the access. that’s why we are all confused i think
A “VNIC” that does WHAT, exactly? How do YOU define a VNIC?
VNIC = Virtual Network Adapter
As we so very often say here: “What larger problem are you trying to solve?” Does A send socket traffic to B, which is on a different, pre-defined, IP Address? So, you want this VNIC to fake the IP address?? What is the problem that needs solving here?
This is part of a larger government contract, so the less I say about “why” the better (if we can just leave it at that, it would be good…)
The requirement (from the powers that be) for the VNIC is to:
provide network interface for Software A
provide network interface for other future software applications
provide ability to bridge disparate network interfaces
**It is important to note that the “lower edge” of the VNIC does not interface directly with h/w; it is the user-mode component PDC ( Software B ) that interfaces with h/w devices that go out to their “cloud”.
Also, for this iteration I wanted to keep Software A & B “as is”.**
I hope this helps to clarify. Sorry for my earlier vagueness. I think in being careful to not divulge too much I just made things more confusing.
Mr @Mark_Holiday … This is frustrating, in many ways,
First, do you see… at the top of the NTDEV list, where it says “ Please Read: Did You Post Something and It Did Not Appear? Edit a Post and Have it Disappear?”? You’ll see this message. Your repeated posts, all 7 of them, were marked as spam. And I had to clean them all up this morning.
And, I’m sorry: “The less said the better” is a cop-out answer, You can be working on a TS/SCI project, and you can describe the engineering requirements in such a way as to not divulge any classified information.
I’m about an inch away from locking this thread, just because it frustrates me and has little chance of providing you any helpful information… mostly because you’re doing nothing to “help us help you.”
You wrote:
The requirement (from the powers that be) for the VNIC is to:
provide network interface for Software A
provide network interface for other future software applications
provide ability to bridge disparate network interfaces
I sincerely fail to understand how Mr. Roberts proverbial “ten line python program” does not adequately fulfill those requirements, if “provide a network interface for Software A” means “provide a connection accessible via sockets.”
And, you know, I think I probably knew what the initials VNIC stood for. So, thanks for spelling it out for me. /rolls eyes
What I was asking is “What functionality, specifically, do you envision as part of this VNIC” and “what attributes of a NIC, specifically, require emulation”?
My apologies - and thank you for that well-deserved scolding! :s
Please understand it is certainly not my intention here to create havoc or waste people’s times. I sincerely appreciate the input from everyone here.
I will go back and review what I have for requirements, and try formulate a more lucid request-for-comments here.
Before we proceed any further, I have to remind you that, assuming that you speak about the full-fledged VNIC that network protocols may bind to, the above mentioned VNIC has to be implemented, on its upper edge, as a NDIS miniport driver. A driver of this kind is not meant to be directly accessed by anyone, apart from NDIS library…
Serving up pending requests (i.e. inverted call model) does seem like the way to go; also,
…which means that it does not receive IRPs from the userland (in fact, from anyone, unless we are speaking about its special control device object that may be used for configuration and has to be the same for all instances of a VNIC, but this is not what we are speaking about here).
Therefore, assuming that you really mean a VNIC, in your particular case you will have to implement it as a layered pair of two kernel modules. Driver A will deal with actually sending and receiving data (if I got it right, this part is done by means of some form of interaction with the userland app), and a driver B will actually implement a VNIC that is presented to the system. It will deal with a driver A on its lower edge and with NDIS library on its upper one, effectively presenting itself a VNIC that protocols may bind to. It is understandable that the inverted call part will be implemented in a driver A.
This is what has to be done in your case if you really mean implementing a VNIC. However, I’ve got a weird feeling that this is a very obvious overkill in your case, and that your problem may be probably solved, indeed, simply by writing a dozen of lines in Python…
Indeed, I was noting that this was part of a government contract project not to “cop out” from providing requirements, but from simply letting you all know that by being sensitive to this, I probably did a poor job in describing the problem at hand.
Also, I am trying to not over-engineer this and make it overly-complicated; this is why I am here in the first place. I am trying to ascertain the best (read: simplest) solution to provide the desired capabilities.
That all being said, I would like to start again, not by describing what we have, but rather what we need.
What we need is a new software “component” that will:
interface with 3rd party network applications, e.g. web browsers, at its upper edge, and existing user-mode proprietary protocol/data controller (call it PDC) at its lower edge. (Note: we do own and have full source code for this PDC module)
provide the ability to facilitate network bridging at TAP (i.e. Ethernet frame) level. For example, we need to allow a workstation to serve as a “gateway connection”, with multiple PDC modules whose “upper edges” are bridged to a real physical NIC that connects to some other WAN/LAN.
Ideally, this would be the same module. Therefore, one current thought is that a software-only virtual network adapter may solve both of these requirements, similar the TAP-Windows driver used by OpenVPN.
I hope this helps to describe the larger problem(s) that we are trying to solve. If more information is required, please let me know.
One last thing: I am asking for help and suggestions here. If you need to point out that something is not clear, or that more information is needed, I have to ask to please not do so in a condescending manner. Some of you may not realize how some of your comments come across. If that request of mine seems out of line, I apologize, but that is simply my opinion.
