This is the patch that puts UDT into the OFF code for better compile. You need two other files "udt.cxx" and "udt.h" to complete this mod.
To patch V0.19.27, make a new directory called "test1", download OFFSystem-0.19.27-src.tar.gz and the patch file into it, like this...
cd test1
tar -xzvf OFFSystem-0.19.27-src.tar.gz
patch -p1 < version_diffs.patch
Then download the two other files "udt.cxx" and "udt.h" that are on the same patch page. Download them to off_network/src/ then do the normal compile...
cd off_network/build_gtk
make
(then do whatever you normally do with a new compiled version)
The OFF client will operate normally via TCP unless you change one configuration option.
When the program is not running, in the "config/offsystem.conf" file, near the end, edit (or make) the use_udp option to enable UDP.
use_udp: 1
You should also rename the "config/known_nodes.txt" file, it contains the IPs of other nodes on the normal OFF network. Renaming it lets you put it back when you want to go back to normal.
You want to start with no "config/known_nodes.txt" or a empty file.
Start the OFF client from a terminal and you will see a lot of debug messages about UDP, showing socket open and a few other messages. UDP is working if you see those messages.
Go to the "Known Nodes" screen and right click then select "Add Node". Type in the other node's IP (and port if different) and a connection should start in about 5 seconds. Both nodes need to be in UDP mode of course.
If the other node has no blocks in it's cache then you will see messages and network activity as it pushes randomly selected blocks to the other node.
patch file