tunneldigger dies somtimes

[ghost]

Original bug report from @Sunz3r under freifunk-gluon/gluon#1188

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If internet lost connection (like reboot of router or plug off lan-cable) then the tunneldigger sometime dies.After strace the tunneldigger i found that a assert is triggered: https://github.com/wlanslovenija/tunneldigger/blob/master/client/asyncns.c#L884https://pastebin.com/R6CQmGXr

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I was not able to report this bug on there site ...

this bug happens when dns-resolution failed and despite sending data through a socket:

 td-client: Failed to send() control packet (errno=89, type=1)!

when dns-resolution suddenly works in this situation then the tunneldigger will crash.

I think there is a bug in the broker selection. The selector should wait for successful address-resolution.

To workaround this bug you can use ip's instead of names.

[mitar]

Have you verified this is still the issue with latest tunneldigger? Because many things around broker selection were improved.

But yes, I think this code path with DNS resolution is less tested because we are not using it ourselves, we have hard-coded IPs.

[ghost]

@Sunz3r: Please provide some feedback

[RalfJung]

We are using DNS names and I have not seen this yet. But the issue is not fully reproducible anyway if I understand the report correctly?

Btw, there is an error in the links in the first post, it seems there are two links directly stuck to each other.

[RalfJung]

I think there is a bug in the broker selection. The selector should wait for successful address-resolution.

I don't follow. Of course it does that, the selector cannot contact a server before address resolution completed.

Isn't this a bug in libasyncns? This is an internal assertion of that library: https://github.com/wlanslovenija/tunneldigger/blob/master/client/libasyncns/asyncns.c#L884

@mitar

Have you verified this is still the issue with latest tunneldigger? Because many things around broker selection were improved.

IIRC Gluon is using the 0.3.0 client. I don't think there were significant changes since then?