Provided by: websockify_0.8.0+dfsg1-9_amd64 bug


       websockify - WebSockets to TCP socket bridge


        websockify [options] [source_addr:]source_port target_addr:target_port
        websockify [options] [source_addr:]source_port -- WRAP_COMMAND_LINE


        -h, --help         show this help message and exit
        -v, --verbose      verbose messages and per frame traffic
        --record=FILE      record sessions to FILE.[session_number]
        -D, --daemon       become a daemon (background process)
        --run-once         handle a single WebSocket connection and exit
        --timeout=TIMEOUT  after TIMEOUT seconds exit when not connected
        --cert=CERT        SSL certificate file
        --key=KEY          SSL key file (if separate from cert)
        --ssl-only         disallow non-encrypted connections
        --web=DIR          run webserver on same port. Serve files from DIR.
        --wrap-mode=MODE   action to take when the wrapped program exits or
                            daemonizes: exit (default), ignore, respawn


       At  the  most  basic  level,  websockify  just translates WebSockets traffic to normal TCP
       socket traffic. Websockify accepts the WebSockets handshake, parses it,  and  then  begins
       forwarding traffic between the client and the target in both directions.

       websockify was formerly named wsproxy and was part of the noVNC project.


   WebSockets binary data
       Websockify  supports  all  versions of the WebSockets protocol (Hixie and HyBI). The older
       Hixie versions of the protocol only support UTF-8 text payloads.  In  order  to  transport
       binary  data  over  UTF-8  an  encoding  must  used  to encapsulate the data within UTF-8.
       Websockify uses base64 to encode all traffic to and from the client. This does not  affect
       the data between websockify and the server.

   Encrypted WebSocket connections (wss://)
       To  encrypt  the  traffic  using  the WebSocket 'wss://' URI scheme you need to generate a
       certificate for websockify to load. By default websockify loads a  certificate  file  name
       self.pem  but  the --cert=CERT option can override the file name. You can generate a self-
       signed certificate using openssl. When asked for the common name, use the hostname of  the
       server where the proxy will be running:

       openssl req -new -x509 -days 365 -nodes -out self.pem -keyout self.pem

   Websock Javascript library
       The  websock.js  (see  Javascript  library  library
       provides a Websock object that is similar to the standard  WebSocket  object  but  Websock
       enables  communication  with raw TCP sockets (i.e. the binary stream) via websockify. This
       is accomplished by base64 encoding the data stream between Websock and websockify.

       Websock has built-in receive queue buffering; the message event does  not  contain  actual
       data  but  is  simply a notification that there is new data available. Several rQ* methods
       are available to read binary data off of the receive queue.

       The Websock API is documented on the websock.js API wiki page:

       See the "Wrap a Program" section below for an example of using Websock and websockify as a
       browser telnet client (wstelnet.html).

   Additional websockify features
       These are not necessary for the basic operation.

       *      Daemonizing:  When the -D option is specified, websockify runs in the background as
              a daemon process.

       *      SSL (the wss:// WebSockets URI): This is detected automatically  by  websockify  by
              sniffing  the  first  byte sent from the client and then wrapping the socket if the
              data starts with '\x16' or '\x80' (indicating SSL).

       *      Flash security policy: websockify detects flash security policy requests (again  by
              sniffing  the  first  packet) and answers with an appropriate flash security policy
              response (and then closes the port). This means no separate flash  security  policy
              server is needed for supporting the flash WebSockets fallback emulator.

       *      Session  recording:  This  feature  that  allows  recording of the traffic sent and
              received from the client to a file using the --record option.

       *      Mini-webserver: websockify can detect and respond to normal  web  requests  on  the
              same  port as the WebSockets proxy and Flash security policy. This functionality is
              activate with the --web DIR option where DIR is the root of the  web  directory  to

       *      Wrap a program: see the "Wrap a Program" section below.

   Wrap a Program
       In  addition  to  proxying  from  a  source address to a target address (which may be on a
       different system), websockify has the ability to launch a program on the local system  and
       proxy WebSockets traffic to a normal TCP port owned/bound by the program.

       The  is  accomplished  with a small LD_PRELOAD library ( which intercepts bind()
       system calls by the program. The specified port is moved to a new localhost/loopback  free
       high port. websockify then proxies WebSockets traffic directed to the original port to the
       new (moved) port of the program.

       The program wrap mode is invoked by replacing the target with -- followed by  the  program
       command line to wrap.

       `./websockify 2023 -- PROGRAM ARGS`

       The  --wrap-mode  option  can  be  used  to  indicate what action to take when the wrapped
       program exits or daemonizes.

       Here is an example of using websockify to wrap the vncserver  command  (which  backgrounds
       itself) for use with noVNC:

       `./websockify 5901 --wrap-mode=ignore -- vncserver -geometry 1024x768 :1`

       Here  is  an  example  of  wrapping  telnetd  (from  krb5-telnetd).telnetd exits after the
       connection closes so the wrap mode is set to respawn the command:

       `sudo ./websockify 2023 --wrap-mode=respawn -- telnetd -debug 2023`

       The wstelnet.html page demonstrates a simple WebSockets based telnet client.


       Joel Martin (