Re: [mosquitto-dev] clarity on disconnect reasons

[Greg Troxel <gdt@xxxxxxxxxx>]

Roger Light <roger@xxxxxxxxxx> writes:

>> Not sure what "connection dropping" means exactly, so hopefully all
>> messags will point someone (who actually understands how this works)
>> precisely to what happened.
>
> Connection dropped means that the client closed its end of the socket,
> or the wifi dropped, or someone dug up an undersea cable... that sort
> of thing. As far as the broker is concerned, the client has
> disappeared and it can't tell why. Other reasons for disconnection
> could be exceeding keepalive, a protocol violation, or an
> authentication error.

Sorry, I meant I get that all of that can happen, but I would like to
know which syscall returned which errno when it hapepns.    Particularly
with NAT state that might go away (NAT device rebooted, client didn't),
and network flakes, it's interesting in terms of system-level
debugging.

(I agree that from mosquitto's POV, if there's an error return on any
syscall for a socket, then it's no good and just closing it is the right
thing.)

I will watch my logs for the next flake, and see if I can be specific
and actually helpful :-)