CMSIS network library

This not a very detailed reply. However, I assume that you have left enabled DHCP, resulting in the fact that your settings may get overwritten.

FYI - the IP address is a variable in Network library - it is either set by DHCP or manually by calling netETH_SetOption(). Both options change the IP address. However if you did that before DHCP has completed (because you've left DHCP enabled in the configuration), your changes get overwritten later, when DHCP has completed.

Hello R. Kopsch,

Thank you for your response.

sorry for the previous replied which had very short explanation.

I'm working on the LPC1837 controller which is based on the ARM cortex-M3. this board is customized one. i need to make my hardware work as router. it consists of one Ethernet port and one USB port. when the USB is connected to PC. my hardware has to assign a IP address to the PC and share the network with PC. I'm using the CMSIS driver to develop the application.

Now coming to problem i'm facing.

i configure my hardware to USB to CDC class and NCM sub class , to make use of Ethernet over USB . This is working fine, but my hardware is acting as Client and PC as server.

i need my hardware to work as server and PC as client so that i can assign IP according to my wish.

so i realized that my hardware should be configure as DHCP server. then i configure my hardware to support the network library.

To make hardware work as router what are the steps i need to follow.

can you please explain it clearly with an example it would be great help.

one more thing i didn't got the API netETH_SetOption() any of the files in the network library. can i know which version of the CMSIS network library you are referring to ?

You seem to mix and match information a lot in your posts, making it almost impossible to understand what you want to say.

- In one post, you talk about the need for having a DHCP server.
- In one post, you talk about issues setting a fixed IP.
- In your latest post, you talk about using a DHCP client while suddenly talking about a DHCP server again.

You talk about "Because i used DHCP server implementation by making the DHCP enable" while linking to a page that has an enable flag for DHCP client.

Your "this didn't work as mentioned" should probably be rewritten as "this didn't work as I incorrectly assumed it should work."

No library of any significant size is bug free. And "fully tested" is also quite problematic since the earth can't supply the electric current to do a full test of many significantly large programs/libraries.

But don't start to assume you suffer from bugs in the library, until you have managed to understand what the library is actually intended to do.

Hello Per Westermark,

Thanks for correcting me.

Can i know how you implemented DHCP server.

Can i know which version of the network library are referring to ?

Hello Per Westermark,

Thank you for your detailed response.

Actually for the first time i'm working on the router development, so i don't have any idea about how to develop a router code.

i think before developing the code, i need learn about how the network protocol works.
how IP addresses are assigned, what frames has to sent first to request the other device to connect. etc..

There are lots of documentation about the DHCP protocol on the net. And there is also a number of DHCP servers available with reasonably licensed source code available.

So the information needed to implement a DHCP server is available - the challenge is to decide what functionality the server needs to implement and what simplifications that can be acceptable. For example do you support just a single PC or can the user make use of a switch and expect to get IP numbers to 100 different units.

Hi Per Westermark,

The functionality of the server needs to assign a IP address to the client which is given by me, for a period of 1 day and i would like to support only one PC.

Can you share the information about this. It would be a great help.

can i know the steps involved from the scratch to develop or if you can share your implement on this.

Here's something i knocked up a few years ago as a simple test:

#!/usr/bin/env python

import socket,traceback

host = '192.168.1.111'
port = 67

s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
s.bind((host, port))

while 1:
        try:
            message, address = s.recvfrom(8192)
            print("DHCP Request detected")
        except (KeyboardInterrupt, SystemExit):
            raise

With a little work, this could become a useful DHCP server. I'll let you figure out how.

"Can you share the information about this. It would be a great help."

Maybe surprise us and spend a bit of own time on the project? I would not earn any money from spending time supplying you with a DHCP server.

If this is a school project, then you are expected to learn.

If this is a hobby project, then the primary reasons would be because you are interested and want to learn.

If this is a commercial project, they you get paid to do this work.