virtual serial port

gistfile1.txt

root@serial:~# cat /etc/rc.local
#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# Print the IP address
_IP=$(hostname -I) || true
if [ "$_IP" ]; then
  printf "My IP address is %s\n" "$_IP"
fi

(
  while sleep 60
  do socat /dev/ttyAMA0,b19200,raw,echo=0 TCP:localhost:2000
  done
) &
exit 0

root@mars:~# cat /etc/ser2net.yaml
%YAML 1.1
---
# This is a ser2net configuration file, tailored to be rather
# simple.
#
# Find detailed documentation in ser2net.yaml(5)
# A fully featured configuration file is in
# /usr/share/doc/ser2net/examples/ser2net.yaml.gz
#
# If you find your configuration more useful than this very simple
# one, please submit it as a bugreport

connection: &con0096
    accepter: tcp,2000
    timeout: 0
    enable: on
    options:
      kickolduser: true
      telnet-brk-on-sync: true
    connector: serialdev,/dev/ttyUSB0,nobreak,19200n81,local
    
root@mars:~# cat /etc/systemd/system/ssh-tunnel-persistent.service
[Unit]
Description=Persistent SSH Tunnel
After=network.target

[Service]
Restart=on-failure
RestartSec=5
ExecStart=/usr/bin/ssh -NTC -o ServerAliveInterval=60 -o ExitOnForwardFailure=yes -R 2000:localhost:2000 tunnel@serial

[Install]
WantedBy=multi-user.target