With all of these tests, your confidence in the results will increase by watching the CoAP messages in Wireshark.
These tests all were developed using native on a recent Ubuntu Linux. However, they all may be run just as well on hardware.
You'll need a recent copy of aiocoap.
Some of these examples use a tap interface with a ULA configured on a Unix-like system as:
$ ip address add fd00:bbbb::1/64 dev tap0 scope global
Use the included setup_tap.sh to automate creation of this interface and
address, and teardown_tap.sh to remove it.
The ULA must be configured manually in the RIOT SUT at the command line with:
> ifconfig 6 add unicast fd00:bbbb::2/64
Notice that the address for the SUT uses host '2', and the other endpoint uses host '1'.
Client registers with an aiocoap CORE Resource Directory (RD) server. Exercises confirmable (CON) client and server messaging with gcoap.
Registration succeeds, and client refreshes registration periodically.
On a Linux machine, start an aiocoap example server with the aiocoap-rd
script.
Start a native terminal for the RIOT cord_ep example app.
Register with the RD server with the command:
> cord_ep register coap://[fd00:bbbb::1]
You should see the message below in the RIOT native terminal:
registration successful
CoAP RD connection status:
RD address: coap://[fd00:bbbb::1]:5683
ep name: RIOT-2D0C232323232323
lifetime: 60s
reg if: /resourcedirectory
location: /reg/1/
Periodically, the client re-registers with the server. You should see the message below in the RIOT terminal:
RD endpoint event: successfully updated client registration
gcoap sends a CON GET request to an aiocoap server. The test runner delays startup of aiocoap to trigger gcoap to resend the message.
gcoap receives the server response and stops resending messages. If the server is not started within the timeout window, gcoap gives up and reports the timeout.
gcoap attempts a maximum of four retries; five messages altogether including the initial one. The retries are timed with CoAP's exponential backoff mechanism and jitter. The retry interval doubles with each attempt and varies +/- 50% of the interval. So, the sequence is:
- original, wait 2 +- 1
- retry 1, wait 4 +- 2
- retry 2, wait 8 +- 4
- retry 3, wait 16 +- 8
- retry 4, wait 32 +-16
- timeout
Start the gcoap example and send a CON message to aiocoap:
> coap get -c fd00:bbbb::1 5683 /time
Wait some period of time, and then start the aiocoap example server
$ server.py
On the next retry gcoap shows it received the response:
gcoap: response Success, code 2.05, 16 bytes
or, if gcoap has timed out:
gcoap: timeout for msg ID 50754
aiocoap slices a payload into a sequence of Block1 encoded POSTs to nanocoap. nanocoap computes and returns the SHA-256 message digest of the payload.
nanocoap returns the expected message digest in a 2.04 response.
Start the nanocoap_server example. Then run task03.py as described in the
comment at the top of that file.
aiocoap GETs a sequence of Block2 encoded packets from nanocoap that encode information about a RIOT instance.
nanocoap returns the expected payload in a 2.05 response.
Start the nanocoap_server example. Then run task04.py as described in the
comment at the top of that file.
aiocoap sends an Observe request to gcoap. gcoap then sends a request itself, which updates its observed resource. This update triggers gcoap to send an Observe notification to aiocoap.
- aiocoap receives an initial response with an Observe option
- gcoap receives a request from aiocoap for /time
- aiocoap receives a following observe notification
Start the gcoap example server. If desired, configure the ULA as described in the Introduction section
> ifconfig 6 add unicast fd00:bbbb::2/64
Start the aiocoap server in task05.py, as described at the top of that file.
aiocoap automatically sends a get request to gcoap to register for the
/cli/stats resource.
aiocoap receives the initial response, which show 0 for the resource value:
First response: <aiocoap.Message at 0x7f84dfa11c18: Type.ACK 2.05 Content
(MID 21466, token 6f1d) remote <UDP6EndpointAddress [fd00:bbbb::2]:5683 with
local address>, 2 option(s), 1 byte(s) payload>
b'0'
Then paste the command below into the gcoap command line:
> coap get -c fd00:bbbb::1 5683 /time
gcoap prints the response below from aiocoap:
gcoap: response Success, code 2.05, 16 bytes
2018-10-30 08:19
aiocoap prints the response below from the Observe notification:
Next result: <aiocoap.Message at 0x7f84dfa15240: Type.NON 2.05 Content
(MID 17807, token 6f1d) remote <UDP6EndpointAddress [fd00:bbbb::2]:5683 with
local address>, 2 option(s), 1 byte(s) payload>
b'1'
Loop ended, wait 10 sec