The 1-Route Protocol: Reach the unreachable.

1-Route.md

The 1-Route Protocol

by Tim Speckhals

Purpose

The Purpose of the 1-Route Protocol is to allow unreachable locations to be reached anyways using a proxy server.

Use Cases

• Your server is being null-routed and you want your files to be accessable whilst you move them to a new location
• Your ISP doesn't allow incoming connections but you want to expose a local service to the public

Existing Implementations

Name	Author	Language(s)	Info
1-Route Implementation	timmyRS	Java	Proxy and Target in one.

The Packet Format

The 1-Route Protocol is a big endian protocol. The default port is 197.

Type	Content
unsigned short	The length of the Packet.
byte	The ID of the Packet.
byte array	The Data of the Packet.

The Packets

0x00 Auth (Target to Proxy)

Type	Content
byte	Protocol Version of the target. The newest is 1.
unsigned short	The length of the following string. 0 (no password) may be accepted by the proxy, but an IP Filter is recommended in that case.
string	The UTF-8 bytes of the password.
byte	The kind of connection this is. See below.
unsigned short	Only sent if the connection is a Proxy Connection. This specifies the port this connection is for.

Connection Types

Byte	Name
0x00	Control Connection
0x01	Proxy Connection

0x01 Ports to Open (Target to Proxy)

This can be sent at any point by the target to tell the proxy to start accepting connections to certain ports.

Type	Content
byte	The length of the following array
unsigned short	Array of ports the proxy shall open and proxy to the target

When the packet has been processed, even when no ports were specified, the proxy will send 0x01 Unaccepted Ports to notify of any ports that could not be opened.

0x02 Ports to Close (Target to Proxy)

This can be sent at any point by the target to tell the proxy to stop accepting connection to certain ports without closing the control connection.

Type	Content
byte	The length of the following array
unsigned short	Array of ports the target will no longer accept and can therefore be closed
boolean	If true, connections on the port must also be closed.

0x00 Auth Response (Proxy to Target)

Type	Content
boolean	Whether the authentication was successful
byte	If the previous is false, this specifies the reason for it. See below.
unsigned short	If the previous is 0x00, this specifies the length of the
string	UTF-8 bytes of the reason why the authentication failed

If the authentication was unsucessful, the connection should be closed by the proxy.

If the authentication was for a Proxy Connection, it should be ensured that the entire packet has been read, as the following data will be the raw bytes sent by the client.

Authentication Failure Reasons

Byte	Name
0x01	IP-Address or Range not allowed
0x02	Protocol Version not supported
0x03	Incorrect Password
0x00	Other

0x01 Unaccepted Ports (Proxy to Target)

Type	Content
byte	The length of the following array
unsigned short	Array of ports which could not be opened

Sent after the target sent 0x01 Ports to Open to notify of any ports that could not be opened.

0x02 Connect (Proxy to Target)

Type	Content
unsigned short	The port which the client has connected to and the local connection would be opened to

It is recommened to check if the port had been sent in Ports to Open to prevent unwanted connections which seemingly come from localhost.

An Example

Client            # Reverse Proxy         # <-----------------> # Target
                  #                       #                     #
                  #                       # <- Auth ----------- #
                  #                       # -- Auth Response -> #
                  # Opens the given ports # <- Ports to Open -- #
Connects to Proxy #                       # -------- Connect -> #
                  #                       #                     # Opens a new connection to the proxy
                  #                       # <-- Auth ---------- #
                  #                       # -- Auth Response -> # Opens a local connection to the given port
                  # Starts proxying       #                     #
                  -------------- Bytes of any other Protocol -> # Proxies the bytes to the local connection
                  #                       #                     #

Handling

• When a local connection of the target is closed, the connection to the proxy should be closed.
• When a proxy connection to the proxy is closed, the proxy should disconnect the client associated with it.
• When the control connection of a target is closed, the proxy should close the ports opened by the target and disconnect all clients connected to the target.