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A private P2P terminal video chat app
Cathode is a weakly-interacting coupling of two peices of software. First we start with p2pvc (the brilliant little app that renders the audio/video in your terminal), and then ZeroTier (an extremely small but very robust encrypted P2P VPN layer). SDK can be found here. We then replace all of the socket API system calls with their ZeroTierSDK equivalents aaaaannnd we're done.
Hint: Use the Glass TTY VT220 font we've included. We think pairs well with cathode, installing this font and increasing your terminal's font size to about 24pt makes this whole experience much more immersive. Have fun!
makemake install
Via ZeroTier-issued IP address:
./cathode fc87:7878:78e2:692c:d103::1 -Z 7878 -V 4545 -v -e
or, via ZeroTier identity:
./cathode 92a0fe61ba -v -port 4545
This app is meant to be a simple demonstration of how you can add ZeroTier to your application. In this example there's only about ten points where modifications to p2pvc were needed. Since we want all network traffic to be handled by ZeroTier we swapped out the system's native calls with our own.
For instance, the p2plib.c's p2p_connect() function, we see:
con->socket = socket(curr_addr->ai_family, curr_addr->ai_socktype, curr_addr->ai_protocol);
We change it to the following:
con->socket = zts_socket(curr_addr->ai_family, curr_addr->ai_socktype, curr_addr->ai_protocol);
We also do this for every instance of bind(), connect(), accept(), listen(), etc. The substituted calls are designed to be perfectly compatible with each system's variation so substitution could be as simple as a find+replace.
If statically-linking isn't an option for your application, we've developed a number of workarounds including function interposition via LD_PRELOAD and SOCKS5 proxy. You can read more about this here