dsptunnel is an IP over audio tunnel.
It allows you to create full duplex point to point tunnels over two stereo links using the kernels TUN/TAP driver.
Outgoing packets are modulated and send over the sound card, incoming packets are demodulated and fed to the TUN/TAP driver.
Data is send using differential signalling for simple clock recovery.
A checksum is appended to every packet to verify data integrity.
With a sound card supporting 48khz sampling rate you can transfer up to 3 kb/sec.
License: GPL V3.0
Source on github: https://github.com/50m30n3/dsptunnel