C++ Builder UDP programming

Hey there!

I'm experimenting with UDP communications in these times, and I'm a bit stuck. I tried to use the built in components in C++ Builder (5.0 by the way), but it does not work.

Could you please help me in this? I don't know which sockets to place, Server, Client, NMUDP, how to interface withit, and stuff.

The thing I'd like to do is the following: Listen on a specific UDP port, and when a packet arrives to my PC I'd like to get the databytes sent in the UDP frame.

It's kinda so painful because I made a microcontroller communicate with the UDP protocol (and I suppose that's a much harder job), and now I'm stuck with just a stupid little problem with this.

So please help me, just as you did in the past. Thanks for that again.

Han

I suppose you really ought to test your quick PC implementation with a simulation of your embedded microcontroller before you actually connect it to the microcontroller.

How do you know that it's sending valid packets?

You should really run ethereal to see if you're getting anything at all sent.

Well I use Ethereal to see the incoming packets. The protocol is okay, the IPs are okay, although the checksum is not very good yet. But anyway, I'd be happy with anything in my software that shows me that something's in. So what I'm looking for are more like advices than components. I trust that the components supplied with C++ Builder are good enough for the job. I just don't know how to use them.

Well using something pre-crafted seems hard work to me, since the examples you see in say Beej are only about 30 lines long to begin with (connect and read a packet).

At least then you'd be able to post what you tried in a nice simple code example rather than all the excess baggage of some bloated object which few here will be able to help you with.

I cannot really post anything, since I don't really understand how this works.

There are the following components available in C++ Builder (supplied with the software):
ClientSocket
ServerSocket
NMUDP

As far as I know, the ClientSocket, and ServerSockets are to make a TCP/IP connection to a server. So it seems to me that I'll have to place a ClientSocket, and an NMUDP component to my software. OR do I only have to place an NMUDP component, since it contains a "remote host" property, which is the IP address of the remote host?

I tried it only with the NMUDP component, but I didn't recieve the packet I saw on Ethereal. (Does it mean that the checksum of the packed is checked upon arrival?)

I've solved the problem. I made a little program which sends a data packet to a given IP, localport, etc. Then I got knee deep into the source code of the microcontroller's UDP implementation (with a RTL8019AS IC), and corrected some bugs.
And nearly that was it. Now, it is working perfectly in both directions (PC to device, device to PC). So I'm done with this problem. If I have questions regarding UDP, I'll post them here.