Added documentation for Transparent HelloWorld

Signed-off-by: Fulvio Risso <[email protected]>

Author: frisso

Documentation/services/index.rst

@@ -11,6 +11,7 @@ This folder contains the list of services (a.k.a. *cubes*) currently available i
     pcn-ddosmitigator/ddosmitigator
     pcn-firewall/firewall
     pcn-helloworld/helloworld
+    pcn-transparenthelloworld/transparenthelloworld
     pcn-iptables/iptables
     pcn-k8sfilter/k8sfilter
     pcn-k8switch/k8switch

Documentation/services/pcn-helloworld/helloworld.rst

@@ -1,9 +1,7 @@
 Helloworld
 ==========
 
-**Note**: documentation of the current release is focused on the final user and not in developers. This service is intended to be used only by developers, so this documentation could be incomplete and have some inacuracies.
-
-This service demonstrates how to create a minimal cube, which includes both the dataplane `fast path` and the control/management `slow path` parts
+This service is oriented to demonstrate to developers how to create a minimal cube, which includes both the dataplane `fast path` and the control/management `slow path`.
 
 Helloworld is a simple service that receives the traffic on a network interface and can either:
 
@@ -18,8 +16,10 @@ How to use
 
 ::
 
-    # create network namespaces
-    # TODO.
+    # create network namespaces with usual commands
+    #   we assume you have two interfaces (veth1 
+    #   and veth2 already working here)
+
 
     # create the instance
     polycubectl helloworld add hw0
@@ -33,7 +33,7 @@ How to use
 
     # send packets to the service
 
-    # try another actions, forward, slowpath
+    # try another action, such as forward
     polycubectl hw0 set action=forward
 
 
@@ -49,6 +49,7 @@ Helloworld includes the minimum amount of code that a service requires to be run
 - **src/helloworld-lib.cpp** contains the implementation of interface that is used when the service is compiled as a shared library.
 - **datamodel/helloworld.yang** contains the service datamodel.
 
+
 Compile and install
 -------------------
 

Documentation/services/pcn-transparenthelloworld/transparenthelloworld.rst

@@ -0,0 +1,50 @@
+Transparent Helloworld
+======================
+
+This service is oriented to demonstrate to developers how to create a minimal transparent cube, which includes both the dataplane `fast path` and the control/management `slow path`.
+
+The behaviour of this service is very similar as :doc:`Helloworld <services/pcn-helloworld/helloworld>`; however, it attaches to an existing interface (in fact, it is *transparent*) instead of having its own set of interfaces.
+From the developer point of view, it inherits from the ``polycube-transparent-base`` datamodel instead of ``polycube-standard-base``.
+
+Transparent Helloworld is a simple service that receives the traffic on a network interface and can either:
+
+- allow packets to pass
+- send packets to the slow path
+- drop packets
+
+The behavior of this service can be changed by setting the ``ingress-action`` and ``egress-action`` flags, which tell the data plane how packets have to be processed.
+In fact, this service can distinguish between *ingress* (i.e., from the network device up to the TCP/IP stack) or *egress* (vice versa) packets, enabling to set different actions for them.
+
+
+How to use
+----------
+
+::
+
+    # we assume a physical interface named 'eth0'
+    # is available in the system
+
+    # create a transparent hello world
+    polycubectl transparenthelloworld add thw0
+
+    # attach to eth0
+    polycubectl attach thw0 eth0
+
+    # you can ping the Internet from your host
+    #    e.g., ping 8.8.8.8
+    # and see that the ping works properly
+
+    # now let's change action in the ingress-path
+    polycubectl thw0 set ingress-action=slowpath
+
+    # now you can see that the ping does no longer work
+    #
+    # in exchange, polycubed prints a log message each
+    # time it receives a new packet in the slow path
+
+    # restore 'pass' behavior
+    polycubectl thw0 set ingress-action=pass
+
+    # now the 'ping' works again
+
+