openssl/demos/easy_tls/README

easy_tls - generic SSL/TLS proxy
========

(... and example for non-blocking SSL/TLS I/O multiplexing.)


  easy_tls.c, easy_tls.h:

     Small generic SSL/TLS proxy library: With a few function calls,
     an application socket will be replaced by a pipe handled by a
     separate SSL/TLS proxy process.  This allows easily adding
     SSL/TLS support to many programs not originally designed for it.

     [Actually easy_tls.c is not a proper library: Customization
     requires defining preprocessor macros while compiling it.
     This is quite confusing, so I'll probably change it.]

     These files may be used under the OpenSSL license.



  test.c, test.h, Makefile, cert.pem, cacerts.pem:

     Rudimentary example program using the easy_tls library, and
     example key and certificates for it.  Usage examples:

       $ ./test 8443     # create server listening at port 8443
       $ ./test 127.0.0.1 8443  # create client, connect to port 8443
                                # at IP address 127.0.0.1

     'test' will not automatically do SSL/TLS, or even read or write
     data -- it must be told to do so on input lines starting
     with a command letter.  'W' means write a line, 'R' means
     read a line, 'C' means close the connection, 'T' means
     start an SSL/TLS proxy.  E.g. (user input tagged with '*'):

     * R
       <<< 220 mail.example.net
     * WSTARTTLS
       >>> STARTTLS
     * R
       <<< 220 Ready to start TLS
     * T
       test_process_init(fd = 3, client_p = 1, apparg = (nil))
       +++ `E:self signed certificate in certificate chain'
       +++ `<... certificate info ...>'
     * WHELO localhost
       >>> HELO localhost
       R
       <<< 250 mail.example.net

     You can even do SSL/TLS over SSL/TLS over SSL/TLS ... by using
     'T' multiple times.  I have no idea why you would want to though.


This code is rather old.  When I find time I will update anything that
should be changed, and improve code comments.  To compile the sample
program 'test' on platforms other then Linux or Solaris, you will have
to edit the Makefile.

As noted above, easy_tls.c will be changed to become a library one
day, which means that future revisions will not be fully compatible to
the current version.

Bodo Möller <bodo@openssl.org>