How to use the latest version of Californium

RE: How to use the latest version of Californium

thread_yoda — Mon, 28 Sep 2020 14:02:30 GMT

Yup, I was thinking whether I should open another Thread already. We will continue the discussion in another post. :) Thanks for your help and Achim Kraus

RE: How to use the latest version of Californium

Didrik Rokhaug — Mon, 28 Sep 2020 13:28:48 GMT

Hi thread_yoda,

I am happy to hear that you got it working.

I did most of the work on version 2.3.0, as that was what was available when I started. But I did also test it briefly with version 2.4.1, so that should work as well.

[quote user="thread_yoda"]Would you be able to give me some pointers on how I would go about testing with the CoAP + Thread + Google iot cloud example that you guys have? I[/quote]

As this thread has become quite long already, and the original issue has been resolved, may I suggest that you open a new ticket?

Best regards,

Didrik

RE: How to use the latest version of Californium

thread_yoda — Fri, 25 Sep 2020 18:08:15 GMT

Didrik Rokhaug Would you be able to give me some pointers on how I would go about testing with the CoAP + Thread + Google iot cloud example that you guys have? I think that is a slightly different mode of operation since the "CoAP server" is actually the device and we are posting updates to the firebase records. What I would like to do is keep the same firmware and see the resource updates on the Californium side of things.

RE: How to use the latest version of Californium

thread_yoda — Fri, 25 Sep 2020 16:41:54 GMT

Got it to work. Think I was too sleepy last night. I had to copy the demo-certs folder to the californium.tools folder and update the path in the client to "../demo-certs .........."

RE: How to use the latest version of Californium

thread_yoda — Fri, 25 Sep 2020 15:40:02 GMT

I'm using Win 10. I downloaded the 2.4.1 tag zip of californium and californium tools to try this with. I did noticed that your screenshot above was with 2.3.0? Maybe it doesn't matter.

RE: How to use the latest version of Californium

Didrik Rokhaug — Fri, 25 Sep 2020 10:53:58 GMT

What OS are you using?

If you are using Linux or macOS, try to change the direction of the slashes, i.e. from \ to /.

RE: How to use the latest version of Californium

thread_yoda — Fri, 25 Sep 2020 08:05:43 GMT

Didrik Rokhaug Everything was fine until I tried to run the secure coap client. I got the following error message saying:

Could not load the keystore
java.io.FileNotFoundException: ..\..\demo-certs\src\main\resources\keyStore.jks (The system cannot find the path specified)
at java.io.FileInputStream.open0(Native Method)
at java.io.FileInputStream.open(FileInputStream.java:195)
at java.io.FileInputStream.<init>(FileInputStream.java:138)
at java.io.FileInputStream.<init>(FileInputStream.java:93)
at org.eclipse.californium.tools.Nrf5xConsoleClient.main(Nrf5xConsoleClient.java:210)
Failed to execute request: URI scheme coaps requires a previous set connector!

Do you know how to fix this?

RE: How to use the latest version of Californium

thread_yoda — Thu, 24 Sep 2020 03:01:33 GMT

Didrik Rokhaug This is really all kinds of awesome, thank you for your kind support and taking the initiative and extra efforts to update this guide. Achim Kraus I will be testing this with our CoAP + Thread example. The nice thing about this is everything flows through Thread as the sensor network backbone and pretty standard to setup using OpenThread border router setup either with standalone Raspberry Pi 3B/3B+ or Ubuntu environment.

RE: How to use the latest version of Californium

Achim Kraus — Mon, 21 Sep 2020 17:20:04 GMT

Last weekend I was also able to spend some time into that.

The most challenging task seems to find a linux distribution with working bluetooth_6lowpan out of the box. On a Ubuntu 18.04 PC it works, for the Raspi OS it seems to disconnect after 30-40s.

Using such "out-of-the-box" bluetooth_6lowpan kernels (newer than 4.12) requires then to compile the iot examples using BLE_6LOWPAN_LEGACY_MODE=0 in the sdk_config.h.

After that it is easy as:

sudo -s (enter su shell, execute the following commands in that shell)

modprobe bluetooth_6lowpan

hcitool lescan

echo "connect 00:AA:BB:CC:DD:EE 1" > /sys/kernel/debug/bluetooth/6lowpan_control

That's it, your device is connected and may be ping6ed. The ping6 response contains the IPv6 address of the device and the host. If you don't get a ping6 response from the device but only from the host itself, check, if the BLE_6LOWPAN_LEGACY_MODE is really set to 0.

To use the iot dtls coap-server example, download the prebuild cf-client from Eclipse Releases - cf-client-2.4.1.jar

With that IPv6 address from the ping6 just start the client on the same host running the bluetooth_6lowpan using:

java -jar cf-client-2.4.1.jar --identity Client_identity --secret secretPSK 'coaps://[fe80::aa:bbff:fecc:ddee%bt0]/lights/led3' --method PUT --payload 2

the out should be something as:

==[ CoAP Request ]=============================================
MID    : 24288
Token : 1CDF1DDD4467DAD3
Type   : CON
Method : 0.03 - PUT
Options: {"Uri-Path":["lights","led3"]}
Payload: 1 Bytes
---------------------------------------------------------------
2
===============================================================

>>> DTLS([fe80:0:0:0:39:d5ff:fe9e:f2eb%bt0]:5684,ID:0E5376F5E6)
>>> TLS_PSK_WITH_AES_256_CCM
>>> PreSharedKey Identity [identity: Client_identity]

Time elapsed (ms): 1352
==[ CoAP Response ]============================================
MID    : 24288
Token : 1CDF1DDD4467DAD3
Type   : ACK
Status : 2.04 - CHANGED
Options: {}
RTT    : 1352 ms
Payload: 0 Bytes
===============================================================

and the LED 3 is switching on. That takes the 1,3 s (no 3 minutes :-) ).

Unfortunately, it's not possible to reconnect the device's server again without disconnect the ble connection. So, if you want to play more, try out the Eclipse Releases - cf-browser-2.4.1. The browser uses javaFX, which is required to be installed ahead. Start the cf-browser similar as cf-client using:

java --module-path /usr/share/openjfx/lib --add-modules javafx.controls,javafx.fxml -jar cf-browser-2.4.1.jar --identity Client_identity --secret secretPSK 'coaps://[fe80::39:d5ff:fe9e:f2eb%bt0]'

(that assumes openjdk java 11 on ubuntu 18.04 using openjfx)

The UI should be easy to use. Press DISCOVER to see the resources of the devices coap-server. Select the resource lights/led3 on the resources tree on the left. select a GET to see the state, or type a 2 and use PUT to toggle the LED.

RE: How to use the latest version of Californium

Didrik Rokhaug — Mon, 21 Sep 2020 14:20:41 GMT

Hi,

I have now added the updated guide as an aswer to this question.

To answer your questions about why the IoT SDK was removed in nRFr5 SDK v17, I recommend you read this answer from one of my collegues: https://devzone.nordicsemi.com/f/nordic-q-a/63386/iot-components-removed-in-nrf5-sdk-v17-0-0/258747#258747

RE: How to use the latest version of Californium

Didrik Rokhaug — Mon, 21 Sep 2020 14:19:36 GMT

Here is an updated version of the guide:

(https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.iotsdk.v0.9.0%2Fiot_sdk_user_guides_java_coaps.html)

Prerequisites:

- Java Developlment Kit

- Eclipse IDE for Java

- Git

- Californium source code. Use git to clone to a local directory. This guide is based on the 2.4.1 tag.

- Californium Tools source code. Use git to clone to a local directory. This guide is based on the 2.4.1 tag.

- This guide is based on nRF5 SDK version 16.0.0 but uses updated Java source files. The new files are attached at the bottom.

Preparing the workspace

Add supplied files to the local repositories

1. Copy the secure CoAP client applcation (1 java source file, don't copy the directory) from coap_guide/pc_client into <Local Repositories>/californium.tools/cf-client/src/main/java/org/eclipse/californium/tools

2. Copy the secure CoAP server application (2 Java source files, don't copy the directory) from coap_guide/pc_server into <Local Repositories>/californium/demo-apps/cf-secure/src/main/java/org/eclipse/californium/examples

Import projects

1. Open a blank workspace in Eclipse.

2. Choose File menu > Import... and select Maven > Existing Maven Projects.

3. Select the directory where you cloned the Californium repository and click Finish.

4. Repeat steps 2 and 3 with the Californium Tools project.

Change settings

1. Open the following file: <Local Repositories>/californium/scandium-core/src/main/java/org/eclipse/californium/scandium/config/DtlsConnectorConfig.java

2. On line 184 set retransmissionTimeout to 20000:

private Integer retransmissionTimeout = 20000;

4. Save and close DtlsConnectoConfig.java.

5. Open the following file: <Local Repositories>/californium/californium-core/src/main/java/org/eclipse/californium/core/network/config/NetworkConfigDefaults.java

6. On line 197 set the default value for ACK_TIMEOUT to 200000:

config.setInt(NetworkConfig.Keys.ACK_TIMEOUT, 200000);

7. Save and close NetworkConfigDefault.java

Known limitations

When trying the examples, there are some limitations and behavior that should be taken into account:

1. When sending the first request from the nRF5x DK, the DTLS handshake phase might take up to 3 minutes to complete.

2. Since the example has no way of knowing if a DTLS session is closed, it cannot free its resources until it is reset. if you invoke the client multiple times, the dev kit will not be able to establish a new session. From the client side, you will appear to get a timeout.

3. If you modify the client to use an unsupported cipher suite, you will get a timeout when trying to connect.

Running a secure CoAP server

1. Open the secure CoAP server implementation: <Local Repositories>/californium/demo-apps/ch-secure/src/main/java/org/eclipse/californium/examples/Nrf5xSecureServer.java

2. On line 99 set the IPv6 address of the local interface that is to be used. E.g.:

InetAddress myIPv6Addr = Inet6Address.getByName("2001:db8:ac10:fe01::1");

3. The secure server is ready to be started by pressing Ctrl+F11.

The expected output of the server is as follows:

(...)
Secure CoAT server powered by Scandium (Sc) is listening on port 5684

Running a secure CoAP client

1. Open the secure CoAP client implementation: <Local Repositories>/californium.tools/cf-client/src/main/java/org/eclipse/californium/tools/Nrf5xConsoleClient.java

2. On line 224 set the IPv6 address of the local interface that is to be used as the source of the CoAP requests. E.g.:

InetAddress myIPv6Addr = Inet6Address.getByName("2001:db8:ac10:fe01::1");

3. To view the documentation of the application run it without command line arguments.

4. In Eclipse, choose the Run menu > Run configuration... item to create a run configuration for Nrf5xConsoleClient.java with the correct command line arguments. Uase coaps as URI scheme for secure requests.

Run configuration for Nrf5xConsoleClient.java. Replace REMOTE_SERVER_IPv6_ADDRESS with actual IPv6 address of the server.

If the DTLS handshake is successfu, the server will print the following lines to the console (these lines will be interleaved with other messages that pertain to the DTLS handshake):

(...)

16 INFO [MessageTracer]: /2001:0DB8:AC10:FE01:0:0:0:1:5694 ==> req CON-GET    MID=14675, Token=0e6e0e5d, OptionSet={"Uri-Path":[".well-known","core"], "Content-Format":"text/plain"}, "" - (org.eclipse.californium.core.network.interceptors.MessageTracer.java:54) receiveRequest() in thread pool-1-thread-2 at (2015-05-26 13:41:23)
16 INFO [MessageTracer]: /2001:0DB8:AC10:FE01:0:0:0:1:5694 <== res ACK-2.05   MID=14675, Token=0e6e0e5d, OptionSet={"Content-Format":"application/link-format"}, "</lights>,</lights/l".. 22 bytes - (org.eclipse.californium.core.network.interceptors.MessageTracer.java:44) sendResponse() in thread pool-1-thread-2 at (2015-05-26 13:41:23)

(...)

The expected output of the client is a follows (these lines will be interleaved with other messages that pertain to the DTLS handshake):

(...)

==[ CoAP Response ]============================================
MID    : 14675
Token  : 0e6e0e5d
Type   : ACK
Status : 2.05
Options: {"Content-Format":"application/link-format"}
Payload: 107 Bytes
---------------------------------------------------------------
</lights>,</lights/led3>;title="nRF DK Resource",</lights/led4>;title="nRF DK Resource",</.well-known/core>
===============================================================
Time elapsed (ms): 1100

Discovered resources:
</lights>,</lights/led3>;title="nRF DK Resource",</lights/led4>;title="nRF DK Resource",</.well-known/core>

devzone.nordicsemi.com/.../coap_5F00_guide.zip

RE: How to use the latest version of Californium

thread_yoda — Fri, 11 Sep 2020 06:54:05 GMT

Hi Achim Kraus and Didrik Rokhaug, thank you for your kind assistance! I have been buried under some other tasks so I was not able to reply until now, but I would look at the changed Didrik made and re-evaluate. It was unclear why the iot examples were removed from the nRF5 SDK v17, but it looks like there is just a separate fork of the mainline code that is the nRF5 SDK 4.1.0 for Thread. In any event, I am using the CoAP example that runs on OpenThread. This is found in: examples\thread\cloud\google_iot_coap

The google coap-proxy demo is just a demo so I was looking to use that firmware example and get it to work with the standalone californium bits. This gives some flexibilty as to where the instance of californium lives. I want to eventually perform the DTLS handshake with X.509 certificates, but for initial test, PSK mode is fine.

RE: How to use the latest version of Californium

Achim Kraus — Sat, 05 Sep 2020 08:03:02 GMT

I currently checked the nrf sdk's for that IoT support - the v16 from Okt 2019 seems to be the last one, the examples/iot has been removed on the v17. So, I'm not sure, if make sense to continue with that migration/update. Maybe "OpenThread" is now the favorite for Nordic, and so I would guess, it will pay more off, to use that.

RE: How to use the latest version of Californium

Achim Kraus — Wed, 02 Sep 2020 16:51:57 GMT

Just to add:

My impression summer 2019 was, that the nrf variants are mainly small modifications of the old californium examples. Therefore I think, apply the changes to the curren californium examples will be easier.

RE: How to use the latest version of Californium

Achim Kraus — Wed, 02 Sep 2020 16:45:10 GMT

My first question:

Does the nrf5 sdk 16 really use x509? if not, a lot of stuff is not required.

Second:

wouldn't it be easier to copy the current SecureServer into Nrf5xSecureServer and add the resources

server.add(new CoapResource("lights").add(new DevKitResource("led3"), new DevKitResource("led4")));

instead of trying to make the "old" Nrf5xSecureServer working with 2.3.0?

Third:

"iot.eclipse.org" is not longer coap ;-(. The Californium sandbox is available under californium.eclipse.org.

And, I also guess, using the new one and apply your adaptions is easier. Even, if I don't know at all, what was added. My feeling is, with the newest 2.4.0 added cli-support to the console, that changes are obsolete.

So, maybe it's easier in both cases to check first the diffs of the old implementations (nrf vs. old californium), and then try to add that diffs to the current implementations. if you post the diffs, I will provide my feedback.

RE: How to use the latest version of Californium

Didrik Rokhaug — Wed, 02 Sep 2020 15:24:03 GMT

Hi thread_yoda and Achim Kraus,

I have now been able to get the guide to work with Californium 2.3.0.

I will do some more testing, update to 2.4.0 and write it down properly, but here are my notes on the changes, and my modified Nrf5xSecureServer/Client.java files (so you don't have to do the modifications to the files listed in the notes under the "Running a secure CoAP server/client):

devzone.nordicsemi.com/.../notes.txt

devzone.nordicsemi.com/.../Nrf5xSecureServer.java

devzone.nordicsemi.com/.../Nrf5xConsoleClient.java

Best regards,

Didrik

RE: How to use the latest version of Californium

Achim Kraus — Wed, 26 Aug 2020 14:54:40 GMT

Hi Didrik,

if I can be of any help, just contact me by e-mail (or a github issue in eclipse/californium).

best regards

Achim

RE: How to use the latest version of Californium

Didrik Rokhaug — Wed, 26 Aug 2020 14:27:09 GMT

Hi thread_yoda and Achim Kraus,

I have now started on updating the guide, and will hopefully have something for you in the next few days.

Best regards,

Didrik

RE: How to use the latest version of Californium

Achim Kraus — Sat, 22 Aug 2020 17:54:09 GMT

In the current 2.3.0 cf-secure example the PSK store is set in the CredentialsUtil.setupCredentials

InMemoryPskStore pskStore = new InMemoryPskStore();
pskStore.setKey(PSK_IDENTITY, PSK_SECRET);
pskStore.setKey(OPEN_PSK_IDENTITY, OPEN_PSK_SECRET);
config.setPskStore(pskStore);

> I think it would be nice if there was some getting started guide with the latest release of californium

Unfortunately, though not too many are actively working "on" Californium, I will not be able to write such a guide for the next release, 2.4.0 planned for Thursday, 27.8.

RE: How to use the latest version of Californium

thread_yoda — Sat, 22 Aug 2020 17:27:14 GMT

Update: I used SecureClient.java and am able to connect to my SecureServer.java instance now, which is cool! I'm going to try and connect my nRF52840-DK to this secure server and see what happens. I'm not sure what to expect.

RE: How to use the latest version of Californium

thread_yoda — Sat, 22 Aug 2020 17:03:01 GMT

Thanks Achim! Yup, I started to just use the Californium release to get my feet wet since as you mentioned I ran into some further issues after attempting to fix the path issue.

I cloned the latest version of californium from github and I was able to successfully run the cf-helloworldserver example and I used Copper (Cu) google chrome extension to access the example hello world resource. This is working fine.

Next, I went to run cf-secure example. This seems to run fine also. But is there a way to use Copper to test this? Or I need some other tool?

I think it would be nice if there was some getting started guide with the latest release of californium (and preferably with Nordic Thread capable dev kits). I have further questions like where the Key store are defined and how to setup the various modes, PSK, X.509, etc. I haven't tried the californium-proxy2 but also I think this needs to be shown how to integrate with DTLS, etc.Anyway, I am trying to get some basic understanding and take the first baby steps...

RE: How to use the latest version of Californium

Achim Kraus — Sat, 22 Aug 2020 15:11:49 GMT

Have a look at Californium Proxy2 .

That documentation doesn't cover right now to use coaps/DTLS (I haven't the time to do so). But with Californium 2.3.0 it is that much easier to setup coaps/DTLS, than it was years ago. If you want your client to use PSK, it's mainly to provide the port the server is listening to and a PSKStore containing the identities and secrets. That should help to start and later you may adapt the defaults in the configuration according your environment and requirements.

RE: How to use the latest version of Californium

Achim Kraus — Sat, 22 Aug 2020 14:48:20 GMT

> Also, it is worth pointing out that you might run into worse problems than just some changed paths. There is a reason why the guide states explicitly which version it was created for.

I'm one of the commiter of Californium. I strongly recommend not to use 5 years old stuff, use our current 2.3.0 release.

RE: How to use the latest version of Californium

thread_yoda — Fri, 21 Aug 2020 16:16:55 GMT

It's the last step that I'm having trouble reconciling:

Copy the whole certs directory from
<Local Repositories>/californium.core/cf-secure/certs
to
<Local Repositories>/californium.tools/cf-client/certs

There is no certs directory, but I do see a top level demo-certs directory. But what do I copy and where?

Yes, I realize the guide was based on an older version of the repo but there is no real reason to go back to an older version of the code. I think the guide should be updated. This is also why I am here to ask for your wisdom. :)

Thanks for additional advice you can provide as we are trying to stand up our own CoAP proxy instance and want to be able to connect Nordic Thread + CoAP examples that we have built to it instead of GCP because the GCP proxy demo is not a commercial offering.

RE: How to use the latest version of Californium

Didrik Rokhaug — Tue, 11 Aug 2020 13:07:04 GMT

Hi.

I am not aware of any updated version of that guide.

However, there doesn't seem to be too big changes in the file structure of the Californium project.

The biggest is probably that the Californium core and Scandium has been gathered into one repo: https://github.com/eclipse/californium

However, except for the top two layers, everything should be the same, and it is quite obvious what the new paths are.

The only path that I had some problems finding the modern equivalent of was californium.core/cf-secure/......./examples.

The new path seems to be https://github.com/eclipse/californium/tree/master/demo-apps/cf-secure/src/main/java/org/eclipse/californium/examples

Are there any other paths, in particular, that are giving you trouble?

Also, it is worth pointing out that you might run into worse problems than just some changed paths. There is a reason why the guide states explicitly which version it was created for.

Best regards,

Didrik