passthru

Passthru

Passthru, a Protocol Omni-multiplexer

Demo: Usage

Build

$ go build ./cmd/passthru

Run

$ ./passthru -c=<configfile> -w=<worker_num> -t=<timeout>

Note that in the current release, the worker_num and timeout are not used for simplicity in demo. You may manually enable it in the main() function.

Config

{
    "version": "v0.2.0",
    "servers": {
        "127.0.0.1:443": {
            "TLS": {
                "SNI gaukas.wang": {
                    "action": "FORWARD",
                    "to_addr": "185.199.111.153:443"
                },
                "SNI google.com": {
                    "action": "FORWARD",
                    "to_addr": "142.250.72.46:443"
                },
                "SNI www.google.com": {
                    "action": "FORWARD",
                    "to_addr": "142.250.72.46:443"
                },
                "CATCHALL": {
                    "action": "REJECT"
                }
            },
            "CATCHALL": {
                "CATCHALL": {
                    "action": "FORWARD",
                    "to_addr": "neverssl.com:80"
                }
            }
        }
    }
}

Packages

Config

The config package is used to parse the config file. The config file follows the structure below:

• Version
• Servers
  • ServerAddr1
    • Protocol1: defined in protocol package
      • Rule1
        • Action: either FORWARD or REJECT
        • ToAddr (FORWARD only): the address to forward to
      • Rule2
        • ...
      • CATCHALL (as a rule)
        • Action
        • ToAddr (optional)
    • Protocol2: defined in protocol package
      • Rule1
        • ...
      • ...
    • CATCHALL (as a protocol)
      • CATCHELL (as the only rule of this protocol)
        • ...
  • ServerAddr2
    • ...

Handler

Handler defines the handler of all incoming connections to a certain address as a Server.

When Server receives a connection, it will first read the first few bytes of the connection to determine the protocol. Then it will pass the connection to the corresponding protocol handler.

Protocol

Protocol defines the identifier/detector of a certain Protocol. It also defines ProtocolManager to manage all known protocols. Upon receiving a buffer of bytes, ProtocolManager will try to match the buffer with all known protocols. If a match is found, the matching Action will be returned.