Peer Manager central device issue

RE: Peer Manager central device issue

Simonr — Wed, 04 Mar 2020 12:32:13 GMT

So you aren't able to get any useful information when debugging your application? Have you tried setting a breakpoint at the PM_EVT_SLAVE_SECURITY_REQ event and go step by step to see what exactly happens? Can you upload the debug log so we might have a look at what happens?

Best regards,

Simon

RE: Peer Manager central device issue

a93radon — Tue, 03 Mar 2020 20:07:48 GMT

Thank you for the informative response. I have tried deleting the peers, but that does not fix the issue.

To elaborate more, when I compare the behavior of the nrf52840 dongle vs nRF Connect on my phone, they both prompt this sequence of events in the peer manager of the advertiser:

PM_EVT_CONN_SEC_PARAMS_REQ

PM_EVT_CONN_SEC_START

PM_EVT_CONN_SEC_PARAMS_REQ

At this point, using my phone, the advertiser prompts my phone to pair, which leads to a successful connection. On the other hand, using the dongle, no pairing is initiated. The peer manager on the dongle side receives the PM_EVT_SLAVE_SECURITY_REQ event before it appears to crash.

What do I need to do in the dongle code to initiate the pairing that I see on the phone?

RE: Peer Manager central device issue

Turbo J — Sat, 29 Feb 2020 10:07:37 GMT

[quote userid="86205" url="~/f/nordic-q-a/58506/peer-manager-central-device-issue"]changes the behavior during the debugging[/quote]

That why the NRF_LOG stuff exists.

You probably ran into the "key deleted on one side" issue - the NRF examples DO NOT allow re-pairing if a key already exists for a peer. You are supposed to delete all peers on BOTH ends in order to make the NRF examples to work.

Reasoning behind this is the MITM or imposter attack: An attacker just claims to have victims MAC address (can be extracted over the air unencrypted) but has no access to the actual keys.

That is why the code that allows re-pairing is intentionally made more difficult to find - re-pairing could block the legit peer from establishing a secure connection.