CC3200 ARP or other discovery method

Iain McDonald

Other Parts Discussed in Thread: CC3200

We're developing a consumer device for the CC3200. During initial setup we need to scan the network for all devices (phones, laptops, PCs or other embedded devices - all platforms) and allow the user to select a few of them. During normal operation, we need to detect if the selected devices are present or not. What's the best way to do this on the CC3200?

Our plan was to use ARP broadcasts to scan the subnet and associate IPs with MACs, then use netbios or DNS to find the hostnames (so the user isn't picking from a list of hex characters). This is proving problematic:

We can't seem to access the ARP table. Other posts have indicated that ARP is buried within the network processor, and doesn't expose any functions to the host.
Netbios is not provided as an API
We could perhaps manually formulate packets, but that seems a risky and arcane process. Also, the transceiver example seems to not work when connected to an AP.

Are we barking up the wrong tree? Can you suggest a way to access the ARP table/ force ARP requests, and resolve the found MAC addresses into hostnames? Is there a better/easier way to find devices on the network?

over 11 years ago

0 Praneet Kumar over 11 years ago

TI__Genius 16370 points

Lain,

I'm checking this internally and shall get back ASAP.

-Praneet

0 Iain McDonald over 11 years ago in reply to Praneet Kumar

Intellectual 625 points

Thanks Praneet, any assistance you could give would be appreciated

0 Ben Gilboa over 11 years ago in reply to Iain McDonald

TI__Intellectual 1630 points

Lain,

ARP tables and logic is not accessible. It is handled in the NWP internaly. I dont see how ARP can help you since you need to know the IP to initiate ARP request. If you know the IP you can ping the device and check its response so why ARP?

mDNS is the common service discovery protocol and CC3200 supports it. Doesn't it meet your needs?

Ben

0 Iain McDonald over 11 years ago in reply to Ben Gilboa

Intellectual 625 points

As we understand it, mDNS requires you to know the target devices' hostnames, which we don't have. I've seen other devices do this task by sending ARP requests for every IP on the subnet (check out FING for an example). Can mDNS scan the whole network for devices, or do we need another solution? We need to identify IP, hostname and MAC (at least) and once we've found them and selected the ones we want, we need to continually check the presence of that MAC

0 Glenn Vassallo over 11 years ago in reply to Iain McDonald

Guru 21435 points

Hi Iain,

As Ben has mentioned, mDNS should be able to provide everything you require, so long as the application you are using to do the "searching" for the devices has mDNS implemented (there are implementations of mDNS available for most platforms/environments)

In the product I've been developing I am using a iOS app which looks for a certain mDNS service that my SimpleLink devices have registered and are advertising. In this advertisement, I can include all sorts of details, which my iOS app can use. The host name, ip address and port number will be included automatically, and you can also provide any additional details you wish, including the MAC address and any specific configuration information.

Glenn.

0 Iain McDonald over 11 years ago in reply to Glenn Vassallo

Intellectual 625 points

After some more testing and research, we've confirmed mDNS doesn't do what we need. We're not trying to find the CC3200 from something else. We need the CC3200 to find all the other devices on the network - phones, computers, xboxes, etc. We don't have control over what those devices are running, and none of them are running mDNS by default.

0 Glenn Vassallo over 11 years ago in reply to Iain McDonald

Guru 21435 points

Hi Ian,

I now understand what you are wanting to accomplish. I do not know much about ARP, but if you believe it will achieve what you require, similar to Fing. You could implement your own ARP "querying" on the CC3200, this may not be too much work if you can find a BSD implementation. A quick search returned this open source one - https://github.com/allfro/libdnet/blob/master/src/arp-bsd.c

Glenn.

0 Iain McDonald over 11 years ago in reply to Glenn Vassallo

Intellectual 625 points

Thanks Glenn, we're working on a port now. I'll post back when we've got results

0 Robert Roth over 10 years ago in reply to Iain McDonald

Intellectual 575 points

Iain,

Have you cracked this? I find myself in the exact position. PF_ROUTE doesn't seem to be implemented in the 3200 and I can't seem to come up with another polling type protocol.

Bob

0 Bernhard Gruchmann over 10 years ago in reply to Robert Roth

Prodigy 10 points

Is there a solution in between ?

I also would prefer to use the hostname instead of an ip.

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CC3200 ARP or other discovery method