udp: add udp decapsulation

Possibility to register a port via CLI or API to decap incoming UDP
packets:
 - For CLI, a user needs to specify the inner protocol (only MPLS
   supported for now)
 - For API, the protocol is specified by index
Added unittests

Type: feature
Change-Id: Ifedd86d8db2e355b7618472554fd67d77a13a4aa
Signed-off-by: Arthur de Kerhor <arthurdekerhor@gmail.com>

2 files changed, 179 insertions, 4 deletions

diff --git a/test/test_udp.py b/test/test_udp.py
index 03a0812a342..3281c0d9df6 100644
--- a/test/test_udp.py
+++ b/test/test_udp.py
@@ -4,12 +4,15 @@ from framework import tag_fixme_vpp_workers
 from framework import VppTestCase, VppTestRunner
 
 from vpp_udp_encap import find_udp_encap, VppUdpEncap
+from vpp_udp_decap import VppUdpDecap
 from vpp_ip_route import VppIpRoute, VppRoutePath, VppIpTable, VppMplsLabel, \
-    FibPathType
+    VppMplsTable, VppMplsRoute, FibPathType, FibPathProto
+from vpp_neighbor import VppNeighbor
+from vpp_papi import VppEnum
 
 from scapy.packet import Raw
 from scapy.layers.l2 import Ether
-from scapy.layers.inet import IP, UDP
+from scapy.layers.inet import IP, UDP, ICMP
 from scapy.layers.inet6 import IPv6
 from scapy.contrib.mpls import MPLS
 
@@ -87,10 +90,13 @@ class TestUdpEncap(VppTestCase):
         else:
             self.assertEqual(rx[IP].ttl, tx[IP].ttl)
 
-    def validate_inner6(self, rx, tx):
+    def validate_inner6(self, rx, tx, hlim=None):
         self.assertEqual(rx.src, tx[IPv6].src)
         self.assertEqual(rx.dst, tx[IPv6].dst)
-        self.assertEqual(rx.hlim, tx[IPv6].hlim)
+        if hlim:
+            self.assertEqual(rx.hlim, hlim)
+        else:
+            self.assertEqual(rx.hlim, tx[IPv6].hlim)
 
     def test_udp_encap(self):
         """ UDP Encap test
@@ -248,6 +254,140 @@ class TestUdpEncap(VppTestCase):
             self.validate_inner4(p, p_4omo4, ttl=63)
         self.assertEqual(udp_encap_1.get_stats()['packets'], 2*NUM_PKTS)
 
+    def test_udp_decap(self):
+        """ UDP Decap test
+        """
+        #
+        # construct a UDP decap object for each type of protocol
+        #
+
+        # IPv4
+        udp_api_proto = VppEnum.vl_api_udp_decap_next_proto_t
+        next_proto = udp_api_proto.UDP_API_DECAP_PROTO_IP4
+        udp_decap_0 = VppUdpDecap(self, 1, 220, next_proto)
+
+        # IPv6
+        next_proto = udp_api_proto.UDP_API_DECAP_PROTO_IP6
+        udp_decap_1 = VppUdpDecap(self, 0, 221, next_proto)
+
+        # MPLS
+        next_proto = udp_api_proto.UDP_API_DECAP_PROTO_MPLS
+        udp_decap_2 = VppUdpDecap(self, 1, 222, next_proto)
+
+        udp_decap_0.add_vpp_config()
+        udp_decap_1.add_vpp_config()
+        udp_decap_2.add_vpp_config()
+
+        #
+        # Routes via the corresponding pg after the UDP decap
+        #
+        route_4 = VppIpRoute(
+            self, "1.1.1.1", 32,
+            [VppRoutePath("0.0.0.0", self.pg0.sw_if_index)],
+            table_id=0)
+
+        route_6 = VppIpRoute(
+            self, "2001::1", 128,
+            [VppRoutePath("::", self.pg1.sw_if_index)],
+            table_id=1)
+
+        route_mo4 = VppIpRoute(
+            self, "3.3.3.3", 32,
+            [VppRoutePath("0.0.0.0", self.pg2.sw_if_index)],
+            table_id=2)
+
+        route_4.add_vpp_config()
+        route_6.add_vpp_config()
+        route_mo4.add_vpp_config()
+
+        #
+        # Adding neighbors to route the packets
+        #
+        n_4 = VppNeighbor(self,
+                          self.pg0.sw_if_index,
+                          "00:11:22:33:44:55",
+                          "1.1.1.1")
+        n_6 = VppNeighbor(self,
+                          self.pg1.sw_if_index,
+                          "11:22:33:44:55:66",
+                          "2001::1")
+        n_mo4 = VppNeighbor(self,
+                            self.pg2.sw_if_index,
+                            "22:33:44:55:66:77",
+                            "3.3.3.3")
+
+        n_4.add_vpp_config()
+        n_6.add_vpp_config()
+        n_mo4.add_vpp_config()
+
+        #
+        # MPLS decapsulation config
+        #
+        mpls_table = VppMplsTable(self, 0)
+        mpls_table.add_vpp_config()
+        mpls_route = VppMplsRoute(
+            self, 77, 1,
+            [VppRoutePath("0.0.0.0",
+                          0xFFFFFFFF,
+                          nh_table_id=2,
+                          proto=FibPathProto.FIB_PATH_NH_PROTO_IP4)])
+        mpls_route.add_vpp_config()
+
+        #
+        # UDP over ipv4 decap
+        #
+        p_4 = (Ether(src=self.pg0.remote_mac,
+                     dst=self.pg0.local_mac) /
+               IP(src=self.pg0.remote_ip4, dst=self.pg0.local_ip4) /
+               UDP(sport=1111, dport=220) /
+               IP(src="2.2.2.2", dst="1.1.1.1") /
+               UDP(sport=1234, dport=4321) /
+               Raw(b'\xa5' * 100))
+
+        rx = self.send_and_expect(self.pg0, p_4*NUM_PKTS, self.pg0)
+        p_4 = IP(p_4["UDP"].payload)
+        for p in rx:
+            p = IP(p["Ether"].payload)
+            self.validate_inner4(p, p_4, ttl=63)
+
+        #
+        # UDP over ipv6 decap
+        #
+        p_6 = (Ether(src=self.pg1.remote_mac,
+                     dst=self.pg1.local_mac) /
+               IPv6(src=self.pg1.remote_ip6, dst=self.pg1.local_ip6) /
+               UDP(sport=2222, dport=221) /
+               IPv6(src="2001::100", dst="2001::1") /
+               UDP(sport=1234, dport=4321) /
+               Raw(b'\xa5' * 100))
+
+        rx = self.send_and_expect(self.pg1, p_6*NUM_PKTS, self.pg1)
+        p_6 = IPv6(p_6["UDP"].payload)
+        p = IPv6(rx[0]["Ether"].payload)
+        for p in rx:
+            p = IPv6(p["Ether"].payload)
+            self.validate_inner6(p, p_6, hlim=63)
+
+        #
+        # UDP over mpls decap
+        #
+        p_mo4 = (Ether(src=self.pg2.remote_mac,
+                       dst=self.pg2.local_mac) /
+                 IP(src=self.pg2.remote_ip4, dst=self.pg2.local_ip4) /
+                 UDP(sport=3333, dport=222) /
+                 MPLS(label=77, ttl=1) /
+                 IP(src="4.4.4.4", dst="3.3.3.3") /
+                 UDP(sport=1234, dport=4321) /
+                 Raw(b'\xa5' * 100))
+
+        self.pg2.enable_mpls()
+        rx = self.send_and_expect(self.pg2, p_mo4*NUM_PKTS, self.pg2)
+        self.pg2.disable_mpls()
+        p_mo4 = IP(MPLS(p_mo4["UDP"].payload).payload)
+        for p in rx:
+            p = IP(p["Ether"].payload)
+            self.validate_inner4(p, p_mo4, ttl=63)
+
 
 @tag_fixme_vpp_workers
 class TestUDP(VppTestCase):
diff --git a/test/vpp_udp_decap.py b/test/vpp_udp_decap.py
new file mode 100644
index 00000000000..2bd03ce75c0
--- /dev/null
+++ b/test/vpp_udp_decap.py
@@ -0,0 +1,35 @@
+#!/usr/bin/env python3
+"""
+  UDP decap objects
+"""
+
+from vpp_object import VppObject
+from socket import inet_pton, inet_ntop, AF_INET, AF_INET6
+
+
+class VppUdpDecap(VppObject):
+
+    def __init__(self,
+                 test,
+                 is_ip4,
+                 dst_port,
+                 next_proto):
+        self._test = test
+        self.active = False
+        self.udp_decap = {
+            'is_ip4': is_ip4,
+            'port': dst_port,
+            'next_proto': next_proto
+        }
+
+    def add_vpp_config(self):
+        self._test.vapi.udp_decap_add_del(True, self.udp_decap)
+        self._test.registry.register(self, self._test.logger)
+        self.active = True
+
+    def query_vpp_config(self):
+        return self.active
+
+    def remove_vpp_config(self):
+        self._test.vapi.udp_decap_add_del(False, self.udp_decap)
+        self.active = False