I believe this is caused by a bug in the linux kernel, since it only impacts certain machines I tested (one, to be specific). Whatever the case, setting a max backlog size is prudent anyway, and fixes the problem.
Packets with a too-short payload would either cause the RCON thread to hang until the client disconnected, or crash the RCON thread entirely.
commit 90bb1894d7f87645b806f5fc67d1b877bb963180
Author: Dylan K. Taylor <odigiman@gmail.com>
Date: Tue Jan 22 18:15:46 2019 +0000
fix some bugs in RCON
This will now throw an exception at the source instead of crashing when the entity is saved, which should put the blame on the correct plugin responsible for this.
This also includes magic method hacks to preserve backwards compatibility, since the fireTicks field is now protected.
Blocks were being overwritten in the writebatch which hadn't yet been set, so reading them from the world yielded air blocks instead of trunk, allowing the generation to overwrite blocks which should have been logs.
This prevents plugins sending wrong packets at the compiler level (or would, if we had a compiler). It's more robust than a getter for client/server and throwing an exception since a static analysis tool can detect faults created by sending wrong packets from the server. This is also used to deny service to dodgy clients which send wrong packets to the server to attack it.
this is in preparation for clientbound/serverbound packet separation. I did this already on another branch, but the changeset was dependent on a massive refactor to split apart packets and binarystream which i'm still not fully happy with.
Encoded tags larger than 32KB overflow the length field, so we can't send these over network. However, it's unreasonable to randomly throw this burden off onto users by crashing their servers, so the next best solution is to just not send the NBT. This is also not an ideal solution (books and the like with too-large tags won't work on the client side) but it's better than crashing the server or client due to a protocol bug. Mojang have confirmed this will be resolved by a future MCPE release, so we'll just work around this problem until then.
