CC2538: Link Key related material

Xian Wang42

Part Number: CC2538

I want to find the code that in the joining part, the coordinator transport the link key to the end device to update from the default link key, but I cannot find it. Is there any code that is related to this part?

Best Regards

Xian Wang

over 8 years ago

0 YiKai Chen over 8 years ago

Guru 735695 points

Try to refer to ZDSecMgrDeviceJoin() in ZDSecMgr.c

0 Xian Wang42 over 8 years ago in reply to YiKai Chen

Expert 1010 points

Yeah, I think I know what you mean, but I do not know the meaning of zdoCBFunc[ZDO_TC_DEVICE_CBID]. How does this part process? Does this mean some kind of callback function?

Best Regards
Xian Wang

0 YiKai Chen over 8 years ago in reply to Xian Wang42

Guru 735695 points

Yes, it is callback function array which is added by ZDO_RegisterForZdoCB().

0 Ryan Brown1 over 8 years ago in reply to Xian Wang42

TI__Guru**** 221687 points

As it stands, MT_ZdoTcDeviceInd handles the ZDO TC Device Indication callback from the ZDO for ZNP/MT purposes, you can refer to MT_ZDO.c for more information. If you'd like to service this callback in your application then you could call ZDO_RegisterForZdoCB(ZDO_TC_DEVICE_CBID, &App_ZdoTcDeviceInd); in your app initialization, where App_ZdoTcDev is defined and implemented elsewhere in your application.

Regards,
Ryan

0 Xian Wang42 over 8 years ago in reply to Ryan Brown1

Expert 1010 points

Thank you for the reply.

Actually my thought is to change the link key in the process to the default one, but actually I did not get the TC link key exchange during the commission stage.

By the way, about ZDO_RegisterForZdoCB(ZDO_TC_DEVICE_CBID, &MT_ZdoTcDeviceInd);, I did not get how it works and how it is related to the TC link key exchange.

Best Regards

Xian Wang

0 Ryan Brown1 over 8 years ago in reply to Xian Wang42

TI__Guru**** 221687 points

I was simply explaining callbacks, you should not concern yourself with MT_ZdoTcDeviceInd as ZDO_TC_DEVICE_CBID is not related to the TC Link Key exchange.

Regards,
Ryan

0 Xian Wang42 over 8 years ago in reply to Ryan Brown1

Expert 1010 points

Thank you for the reply.

If I want to manually update the TC Link key in my application, is there any API that I can use as references?

Best Regards
Xian Wang

0 YiKai Chen over 8 years ago in reply to Xian Wang42

Guru 735695 points

Try to use API ZDSecMgrAddLinkKey.

0 Xian Wang42 over 8 years ago in reply to YiKai Chen

Expert 1010 points

Is there any seq number for the link key? There are several network keys stored in the system and one for a unique sequence number.

Best Regards
Xian Wang

0 YiKai Chen over 8 years ago in reply to Xian Wang42

Guru 735695 points

I am not aware of this.

0 Ryan Brown1 over 7 years ago in reply to Xian Wang42

TI__Guru**** 221687 points

Can you please further clarify your intent? The ZDSecMgrAddLinkKey API passes short/extended addresses and the link key as parameters. ZDSecMgrUpdateNwkKey() and ZDSecMgrSwitchNwkKey() allows the Trust Center to send a new Network key to the dstAddr on the network before updating accordingly.The The default Trust Center link key is stored in nwk_globals.h and should not be modified if interoperability with Z3.0 devices is desired.

Regards,
Ryan

0 Xian Wang42 over 7 years ago in reply to Ryan Brown1

Expert 1010 points

Thank you for the reply.

I just want to use the default TC link key in the communication. Since Z3.0 right now has one link key exchange stage, I just wanted to ask how to change the link key back to the default one. Or where is the link key exchange part that I can just comment those part code.

Best Regards

Xian Wang

0 Ryan Brown1 over 7 years ago in reply to Xian Wang42

TI__Guru**** 221687 points

Joining devices may skip the TCLK exchange procedure by setting requestNewTrustCenterLinkKey to FALSE (ZDSecMGr.c) to allow Z3.0 devices to deploy a custom large network without requiring big tables of TCLK in Coordinator devices. However, this should not be used if interoperability with certified Z3.0 devices is intended.

Regards,
Ryan

0 Xian Wang42 over 7 years ago in reply to Ryan Brown1

Expert 1010 points

Thank you for the reply.

So if I change the network after the commission stage and then change the link key back to the default one, is that OK?
If so, I can use ZDSecMgrAddLinkKey(), right? And how I set the default key in the parameter? DEFAULT_TC_LINK_KEY?

Best Regards
Xian Wang

0 Ryan Brown1 over 7 years ago in reply to Xian Wang42

TI__Guru**** 221687 points

Not too great from a security or certification standpoint but try it out and let us know if you encounter any issues.

Regards,
Ryan

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CC2538: Link Key related material