Infinite failure trying to download userfile

[Pixelz]

This is a rare long-standing bug with Eggdrop that has gauded Eggdrop users for years.

In a botnet situation, a leaf will delink after having been linked for months (unclear if this is a requirement), most likely due to unrelated causes. After that, the leaf will re-link to the hub and try to download the userfile. The transfer will fail and the leaf will disconnect because of a failed userfile transfer.

After this the leaf re-links again and enters an infinite loop failing to download the userfile. A restart fixes it.

[Cizzle]

Can confirm this; a manual .unlink and .link fixes this too but can't remember if this has to be done on the hub or leaf.

[michaelortmann]

i would like to change userfile transfer, to transfer the data via the botlink already established. opening a second tcp channel looks troublesome and harder to do right. we could of course keep the old mechanism as fallback if a bot doesnt support the new method yet. or do you know any good reason why we should need that second tcp chan?