You can’t use ssh (or any protocol) over port 22, only certain ports are allowed for team use. You can use SSH, HTTP, Telnet, etc. as you please within a range of a few allocated ports:
The following ports are opened for communication between your Robot and Driver Station. All other ports are blocked. All ports are bidirectional unless otherwise stated.
- UDP/TCP 1180 - 1190: Camera Data
- TCP 1735: SmartDashboard
- UDP 1130: DS-to-Robot control data
- UDP 1140: Robot-to-DS status data
- HTTP 80: Camera/web interface
- HTTP 443: Camera/web interface (secure)
- UDP/TCP 554: Real-Time Streaming Protocol for h.264 camera streaming
- UDP/TCP 5800-5810: Team Use
Teams are permitted to utilize ports 5800-5810 for their own purposes, or any other open ports (other than 1130 and 1140) if not already allocated.
edit to add: not directly related to your question, but while we are on the topic of FRC radio firmware behavior, it’s also worth noting that there is a bandwidth limit of 4 Mbit/s across all ports that will be enforced by the FMS during competition and will be enforced by the radio using team-use firmware if that box is checked in the Radio Configuration Utility
Source: 2019 FMS Whitepaper