feat: update mosquitto strings

[Its-Just-Nans]

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---

Hello

• Add the correct connack codes (add fixes the usage of it)
• Add a function for disconnect

[codecov]

Codecov Report

❌ Patch coverage is 92.03540% with 9 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
apps/mosquitto_ctrl/client.c	0.00%	2 Missing ⚠️
client/pub_client.c	0.00%	2 Missing ⚠️
client/sub_client.c	0.00%	2 Missing ⚠️
lib/cpp/mosquittopp.cpp	0.00%	2 Missing ⚠️
client/rr_client.c	0.00%	1 Missing ⚠️

Files with missing lines	Coverage Δ
lib/srv_mosq.c	0.00% <ø> (ø)
libcommon/strings_common.c	100.00% <100.00%> (ø)
client/rr_client.c	74.19% <0.00%> (ø)
apps/mosquitto_ctrl/client.c	76.56% <0.00%> (+2.32%)	⬆️
client/pub_client.c	81.42% <0.00%> (+0.46%)	⬆️
client/sub_client.c	78.62% <0.00%> (+0.59%)	⬆️
lib/cpp/mosquittopp.cpp	76.34% <0.00%> (-0.64%)	⬇️

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[ralight]

I don't think I agree with this change. Could you explain what problem you believe it to be solving?

[Its-Just-Nans]

I don't think I agree with this change. Could you explain what problem you believe it to be solving?

mosquitto_connack_string() is incorrect for the MQTT v5 as it currently handle only code from 0 to 5

mosquitto/libcommon/strings_common.c

Lines 148 to 166 in 7786833

	const char *mosquitto_connack_string(int connack_code)
	{
	switch(connack_code){
	case 0:
	return "Connection Accepted";
	case 1:
	return "Connection Refused: unacceptable protocol version";
	case 2:
	return "Connection Refused: identifier rejected";
	case 3:
	return "Connection Refused: broker unavailable";
	case 4:
	return "Connection Refused: bad user name or password";
	case 5:
	return "Connection Refused: not authorised";
	default:
	return "Connection Refused: unknown reason";
	}
	}

Currentlyt, to get the string of a connack code, we should do

• mosquitto_connack_string() for MQTTv3
• mosquitto_reason_string() for MQTTv5

And it's also not documented if I'm correct - only as comment here

mosquitto/examples/subscribe/basic-1.c

Lines 17 to 20 in 7786833

	/* Print out the connection result. mosquitto_connack_string() produces an
	* appropriate string for MQTT v3.x clients, the equivalent for MQTT v5.0
	* clients is mosquitto_reason_string().
	*/

This fix, update the mosquitto_connack_string for both

• MQTTv3 3.2.2.3 Connect Return code on https://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html
• MQTTv5 3.2.2.2 Connect Reason Code on https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901079

Also I've added strings for disconnect code translation using mosquitto_disconnect_string() for the 3.14.2.1 Disconnect Reason Code on https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901208
also adding test, and fixing examples

[ralight]

Ah, thank you I understand. I believe the answer is to better document it then. There is no such thing as a connack code/string in MQTT v5.0, and no such thing as a reason code/string in MQTT v3.1.1, so mixing the two doesn't make sense to me.

[Its-Just-Nans]

Hum that's strange because on MQTTv5 (https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html) I see

• 2.4 Reason Code
• 3.2.2.2 Connect Reason Code

On MQTTv3 I see

• 3.2.2.3 Connect Return code

On MQTTv5, the codes from 2.4 have a general name e.g

Paragraph	code
2.4 Reason Code	155 - 0x9B - QoS not supported
3.2.2.2 Connect Reason Code	155 - 0x9B - QoS not supported - The Server does not support the QoS set in Will QoS.
3.14.2.1 Disconnect Reason Code	155 - 0x9B - QoS not supported - The Client specified a QoS greater than the QoS specified in a Maximum QoS in the CONNACK.

What do you think about the mosquitto_disconnect_string()?

What do you think about the mosquitto_connack_string() handling also MQTTv5 code?
For example if(code > 5) return mosquitto_reason_string(code)

I can also edit the documentation if needed