add classify session action set-sr-policy-index

This allows to use the classifier to steer source routing packets instead
of using the "sr steer" command.
This way we can steer on anything instead of only the dst ip address.

test:
 * add add_node_next function to the VppPapiProvider class.
 * add simple test scenario using the classifier to steer packets with
   dest ip addr == a7::/8 to the source routing insert node.
 * use new interface indexes (3,4) instead of (0,1) to prevent a cleanup
   conflict with the other tests which attach a specific fib to the
   interface.

The test creates interfaces sepsrated from the other tests to prevent a
conflict in the cleaning of the ip6 fib index 1 which causes vpp not to
be able to find a default route on this table.

Change-Id: Ibacb30fab3ce53f0dfe848ca6a8cdf0d111d8336
Signed-off-by: Gabriel Ganne <gabriel.ganne@enea.com>

test/test_srv6.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 
 import unittest
+import binascii
 from socket import AF_INET6
 
 from framework import VppTestCase, VppTestRunner
@@ -1165,6 +1166,150 @@ class TestSRv6(VppTestCase):
         # cleanup interfaces
         self.teardown_interfaces()
 
+    def test_SRv6_T_Insert_Classifier(self):
+        """ Test SRv6 Transit.Insert behavior (IPv6 only).
+            steer packets using the classifier
+        """
+        # send traffic to one destination interface
+        # source and destination are IPv6 only
+        self.setup_interfaces(ipv6=[False, False, False, True, True])
+
+        # configure FIB entries
+        route = VppIpRoute(self, "a4::", 64,
+                           [VppRoutePath(self.pg4.remote_ip6,
+                                         self.pg4.sw_if_index,
+                                         proto=DpoProto.DPO_PROTO_IP6)],
+                           is_ip6=1)
+        route.add_vpp_config()
+
+        # configure encaps IPv6 source address
+        # needs to be done before SR Policy config
+        # TODO: API?
+        self.vapi.cli("set sr encaps source addr a3::")
+
+        bsid = 'a3::9999:1'
+        # configure SRv6 Policy
+        # Note: segment list order: first -> last
+        sr_policy = VppSRv6Policy(
+            self, bsid=bsid,
+            is_encap=0,
+            sr_type=SRv6PolicyType.SR_POLICY_TYPE_DEFAULT,
+            weight=1, fib_table=0,
+            segments=['a4::', 'a5::', 'a6::c7'],
+            source='a3::')
+        sr_policy.add_vpp_config()
+        self.sr_policy = sr_policy
+
+        # log the sr policies
+        self.logger.info(self.vapi.cli("show sr policies"))
+
+        # add classify table
+        # mask on dst ip address prefix a7::/8
+        mask = '{:0<16}'.format('ff')
+        r = self.vapi.classify_add_del_table(
+            1,
+            binascii.unhexlify(mask),
+            match_n_vectors=(len(mask) - 1) // 32 + 1,
+            current_data_flag=1,
+            skip_n_vectors=2)  # data offset
+        self.assertIsNotNone(r, msg='No response msg for add_del_table')
+        table_index = r.new_table_index
+
+        # add the source routign node as a ip6 inacl netxt node
+        r = self.vapi.add_node_next('ip6-inacl',
+                                    'sr-pl-rewrite-insert')
+        inacl_next_node_index = r.node_index
+
+        match = '{:0<16}'.format('a7')
+        r = self.vapi.classify_add_del_session(
+            1,
+            table_index,
+            binascii.unhexlify(match),
+            hit_next_index=inacl_next_node_index,
+            action=3,
+            metadata=0)  # sr policy index
+        self.assertIsNotNone(r, msg='No response msg for add_del_session')
+
+        # log the classify table used in the steering policy
+        self.logger.info(self.vapi.cli("show classify table"))
+
+        r = self.vapi.input_acl_set_interface(
+            is_add=1,
+            sw_if_index=self.pg3.sw_if_index,
+            ip6_table_index=table_index)
+        self.assertIsNotNone(r,
+                             msg='No response msg for input_acl_set_interface')
+
+        # log the ip6 inacl
+        self.logger.info(self.vapi.cli("show inacl type ip6"))
+
+        # create packets
+        count = len(self.pg_packet_sizes)
+        dst_inner = 'a7::1234'
+        pkts = []
+
+        # create IPv6 packets without SRH
+        packet_header = self.create_packet_header_IPv6(dst_inner)
+        # create traffic stream pg3->pg4
+        pkts.extend(self.create_stream(self.pg3, self.pg4, packet_header,
+                                       self.pg_packet_sizes, count))
+
+        # create IPv6 packets with SRH
+        # packets with segments-left 1, active segment a7::
+        packet_header = self.create_packet_header_IPv6_SRH(
+            sidlist=['a8::', 'a7::', 'a6::'],
+            segleft=1)
+        # create traffic stream pg3->pg4
+        pkts.extend(self.create_stream(self.pg3, self.pg4, packet_header,
+                                       self.pg_packet_sizes, count))
+
+        # send packets and verify received packets
+        self.send_and_verify_pkts(self.pg3, pkts, self.pg4,
+                                  self.compare_rx_tx_packet_T_Insert)
+
+        # remove the interface l2 input feature
+        r = self.vapi.input_acl_set_interface(
+            is_add=0,
+            sw_if_index=self.pg3.sw_if_index,
+            ip6_table_index=table_index)
+        self.assertIsNotNone(r,
+                             msg='No response msg for input_acl_set_interface')
+
+        # log the ip6 inacl after cleaning
+        self.logger.info(self.vapi.cli("show inacl type ip6"))
+
+        # log the localsid counters
+        self.logger.info(self.vapi.cli("show sr localsid"))
+
+        # remove classifier SR steering
+        # classifier_steering.remove_vpp_config()
+        self.logger.info(self.vapi.cli("show sr steering policies"))
+
+        # remove SR Policies
+        self.sr_policy.remove_vpp_config()
+        self.logger.info(self.vapi.cli("show sr policies"))
+
+        # remove classify session and table
+        r = self.vapi.classify_add_del_session(
+            0,
+            table_index,
+            binascii.unhexlify(match))
+        self.assertIsNotNone(r, msg='No response msg for add_del_session')
+
+        r = self.vapi.classify_add_del_table(
+            0,
+            binascii.unhexlify(mask),
+            table_index=table_index)
+        self.assertIsNotNone(r, msg='No response msg for add_del_table')
+
+        self.logger.info(self.vapi.cli("show classify table"))
+
+        # remove FIB entries
+        # done by tearDown
+
+        # cleanup interfaces
+        self.teardown_interfaces()
+
     def compare_rx_tx_packet_T_Encaps(self, tx_pkt, rx_pkt):
         """ Compare input and output packet after passing T.Encaps