Add PPPoE Plugin

Supports 64K PPPoE sessions

This plugin adds three graph nodes:
1) pppoe-input for PPPoE decapsulation
2) pppoe-encap for PPPoE encapsulation
3) pppoe-tap-dispatch for control plane process

Below is the configuration to make PPPoE CP and DP work:
vim /etc/vpp/startup.conf
tuntap {
  enable
  ethernet
  name newtap
}

create pppoe tap tap-if-index 1

//Configure it after a subscriber's PPPoE discovery and PPP link establishment succeeds:
create pppoe session client-ip 100.1.2.1 session-id 1 client-mac 00:11:01:00:00:01

show pppoe fib
show pppoe session

Change-Id: I73e724b6bf7c3e4181a9914c5752da1fa72d7e60
Signed-off-by: Hongjun Ni <hongjun.ni@intel.com>

test/vpp_papi_provider.py

@@ -2087,3 +2087,29 @@ class VppPapiProvider(object):
                          'decap_vrf_id': decap_vrf_id,
                          'protocol': protocol,
                          'vni': vni})
+
+    def pppoe_add_del_session(
+            self,
+            client_ip,
+            client_mac,
+            session_id=0,
+            is_add=1,
+            is_ipv6=0,
+            decap_vrf_id=0):
+        """
+
+        :param is_add:  (Default value = 1)
+        :param is_ipv6:  (Default value = 0)
+        :param client_ip:
+        :param session_id:  (Default value = 0)
+        :param client_mac:
+        :param decap_vrf_id:  (Default value = 0)
+
+        """
+        return self.api(self.papi.pppoe_add_del_session,
+                        {'is_add': is_add,
+                         'is_ipv6': is_ipv6,
+                         'session_id': session_id,
+                         'client_ip': client_ip,
+                         'decap_vrf_id': decap_vrf_id,
+                         'client_mac': client_mac})