protocol

网络端口的服务程序

[This document should not be considered a complete description
of the protocol, as it is still under development.]

The RTERM protocol is very simple.

The data stream consists of data and commands.  Immediately after
opening a connection to an RTERM server, all data is ignored until
an <open ...> command successfully associates this connection with
a serial port.  As long as the connection is associated with a port, 
all data received from the connection is transferred to the port and
all data received from the serial port is sent back over the network.

Commands are enclosed in '<' and '>'.  If you need to transmit
a '<' as data, send it as '<<'.  Arguments to commands are separated
by whitespace and are send before the closing '>'.

Commands are not case sensitive.  There is no mechanism for quoting
arguments, so arguments cannot contain whitespace or '>' characters.

The response to a command is also enclosed in '<' and '>'.  The 
first character of the response is either '+' to indicate success
or '-' to indicate an error.

The following commands are defined:

<open arg>
   Requests that this connection be associated with serial port 'arg'.
   In portserver's implementation, 'arg' must the name of a port 
   defined in the configuration file.  Other implementations are free
   to interpret 'arg' in other ways, such as a Unix-style device name
   (e.g. "/dev/tty1").

<close>
   Disconnect from the serial port.  It is an error to use this 
   command if not currently associated with a port.

<disc>
   Disconnect from a serial port, if connected, and close the network
   connection.  Closing the TCP connection on the client side has the
   same effect as this command.

<echo arg1 ... argN>
   The arguments are echoed back as the response.  Used for testing.

<speed baud-rate>
   Set the baud rate of the serial port to the rate specified.

<connections>
   List the currently active connections.  The response to this 
   command will look like:

      <+OK user,portname,device,description
      *,kenn@localhost,none,none,none
      -,user@somehost,Modem,/dev/cua1,External 33.6K Modem
      >

   The first line is explanatory.  Each subsequent line will have
   five comma-separated fields:

      Current:  '*' if this is the connection that is executing the
                <connections> command.  '-' otherwise.

      User@host:  the user and originating host as determined by
                tcpwrappers

      Port:     the name of the port being used by this connection
                or 'none' if this connection is not using any port

      Device:   the name of the physical device being used
                or 'none' if this connection is not using any port

      Description:  the description of the port as supplied in the 
                config file or 'none' if this connection is not 
                using any port

<ports>
   List all ports currently available.  The response to this 
   command will look like:

      <+OK user,portname,device,description
      -,none,com1,/dev/cua0,Local serial port 1
      -,user@somehost,Modem,/dev/cua1,External 33.6K Modem
      *,kenn@localhost,com3,/dev/cua2,Local serial port 3
      >

   The first line is explanatory.  Each subsequent line will have
   five comma-separated fields:

      Current:  '*' if this port is in use by the connection that 
                is executing the <ports> command.  '-' otherwise.

      User@host:  the user and originating host as determined by
                tcpwrappers, or 'none' if this port is not in use

      Port:     the name of the port 

      Device:   the name of the physical device 

      Description:  the description of the port as supplied in the 
                config file