support for line disciplines (TTY, PPP)

ttynvt now uses pseudoterminal (pty) to be able to get use of
the tty line disciplines.
Currently only the line discipline: TTY and PPP are supported.

README

@@ -1,3 +1,20 @@
+ttynvt makes a virtual serial device (tty) and connects
+the device to a Network Virtual Terminal (NVT).
+
+                 +-ttynvt-+------------------------+
+                 |        |\                       |
+                 |        | +---------------+      |
+                 |        |                 |      |
+                 |        |                 |      |
+   /dev/ttyNVT   |       pty   /dev/ppp    pty     |
+        |        |      slave      |      master   |
+        |        |        |        |        |      |
+   --------------------------------------------------
+        |        |        |        |        |      |
+        |        |        |        |        |      |
+        +--FUSE--+        +-tty--ldisc------+     TCP--->host
+
+
 1 Build environment
   The gcc compiler is used by default (see Makefile).
   libfuse-dev - Filesystem in Userspace (development) must be installed
@@ -9,8 +26,12 @@
   libpthread and libfuse must be installed in the root filesystem.
 
 3 Build
-   The default target in the Makefile builds the Network Virtual Terminal.
-   Output name is: ttynvt.
+  $ autoreconf -vif
+  $ ./configure ...
+  $ make
+
+  The default target in the Makefile builds the Network Virtual Terminal.
+  Output name is: ttynvt.
 
 4 Run
   The application (ttynvt) installs a virtual serial device in the /dev
@@ -20,7 +41,7 @@
   is started (command-line options).
 
   E.g.
-  ./ttynvt -M 199 -m 6 -n ttyNVT0 -p 5020 -s 169.254.1.1
+  ./ttynvt -M 199 -m 6 -n ttyNVT0 -s 169.254.1.1:5020
 
   To get a list of all command-line options:
   ./ttynvt --help
@@ -28,7 +49,7 @@
 5. Test
    The serial server: ser2net (http://ser2net.sourceforge.net/) might be used
    to test the virtual serial server on the target.
-   Install the server (ser2net) and add folling line to the configuration
+   Install the server (ser2net) and add following line to the configuration
    file (/etc/ser2net.conf):
    5020:telnet:0:/dev/ttyS0:115200 remctl NONE 1STOPBIT 8DATABITS RTSCTS HANGUP_WHEN_DONE
    At the server, plug-in a loopback connector in the serial port (ttyS0).
@@ -37,7 +58,8 @@
    minicom -D /dev/ttyNVT0
 
 6 Diagnostic
-  Add the command-line option '-l' to enable logging of diagnostic information.
+  Add the command-line option '-D <level>' to enable logging of diagnostic information.
+  The log is forwarded to syslog with the debug level.
   Wireshark is also very useful when debugging the interface between the client
   and the server.