Today I am attempting to set up an MQTT connection from a Thread device to an MQTT server on the Internet (for better or for worse, if this is a terrible idea I'm open to suggestions).
I've done some preliminary investigation using the Thread CLI example and am now starting to develop code using the Thread API in SDK 2.6.0. I have a border router running on an RPi with NAT64.
At this point I can do a DNS lookup using otDnsClientResolveIp4Address, sending the request to fd34:e64f:ccd9:02:0:0:808:808 (i.e. 8.8.8.8) and I get back the address of the MQTT server as a synthesized IPv6 address. I can ping this address and get a response.
The next step is to attempt an MQTT connection.
I start by calling getaddrinfo() to resolve the IP address of the broker, this fails with -ENOENT, it's the same whether I use hints.ai_family = AF_INET or AF_INET6.
So instead I tried using the address returned by the earlier DNS lookup. Then I call mqtt_connect() but get -EPROTOTYPE (protocol wrong type for socket).
I see some discussion in DevZone from people trying to do similar things but none quite the same as this. Perhaps I'm being naive thinking that it should 'just work'?
Any suggestions will be gladly received.
Thanks,
Frog
