package tunnel

import "veyron2/security"

// Tunnel creates a network tunnel from the client to the server.

type Tunnel interface {
  // The Forward method is used for network forwarding. All the data sent over
  // the byte stream is forwarded to the requested network address and all the
  // data received from that network connection is sent back in the reply
  // stream.
  Forward(network, address string) stream<[]byte, []byte> error {security.AdminLabel}

  // The Shell method is used to either run shell commands remotely, or to open
  // an interactive shell. The data received over the byte stream is sent to the
  // shell's stdin, and the data received from the shell's stdout and stderr is
  // sent back in the reply stream. It returns the exit status of the shell
  // command.
  Shell(command string, shellOpts ShellOpts) stream<ClientShellPacket, ServerShellPacket> (int32, error) {security.AdminLabel}
}

type ShellOpts struct {
  UsePty      bool      // Whether to open a pseudo-terminal
  Environment []string  // Environment variables to pass to the remote shell.
  Rows, Cols  uint32    // Window size.
}

type ClientShellPacket struct {
  // Bytes going to the shell's stdin.
  Stdin      []byte
  // Indicates that stdin should be closed.
  EOF        bool
  // A dynamic update of the window size. The default value of 0 means no-change.
  Rows, Cols uint32
}

type ServerShellPacket struct {
  // Bytes coming from the shell's stdout.
  Stdout []byte
  // Bytes coming from the shell's stderr.
  Stderr []byte
}