#!/usr/bin/env python

import unittest

from scapy.packet import Raw
from scapy.layers.l2 import Ether, Dot1Q, GRE, ERSPAN
from scapy.layers.inet import IP, UDP
from scapy.layers.vxlan import VXLAN

from framework import VppTestCase, VppTestRunner
from util import Host, ppp
from vpp_sub_interface import VppDot1QSubint, VppDot1ADSubint
from vpp_gre_interface import VppGreInterface, VppGre6Interface
from vpp_papi_provider import L2_VTR_OP
from collections import namedtuple

Tag = namedtuple('Tag', ['dot1', 'vlan'])
DOT1AD = 0x88A8
DOT1Q = 0x8100


class TestSpan(VppTestCase):
    """ SPAN Test Case """

    @classmethod
    def setUpClass(cls):
        super(TestSpan, cls).setUpClass()
        # Test variables
        cls.pkts_per_burst = 257    # Number of packets per burst
        # create 3 pg interfaces
        cls.create_pg_interfaces(range(3))

        cls.bd_id = 55
        cls.sub_if = VppDot1QSubint(cls, cls.pg0, 100)
        cls.vlan_sub_if = VppDot1QSubint(cls, cls.pg2, 300)
        cls.vlan_sub_if.set_vtr(L2_VTR_OP.L2_POP_1, tag=300)

        cls.qinq_sub_if = VppDot1ADSubint(cls, cls.pg2, 33, 400, 500)
        cls.qinq_sub_if.set_vtr(L2_VTR_OP.L2_POP_2, outer=500, inner=400)

        # packet flows mapping pg0 -> pg1, pg2 -> pg3, etc.
        cls.flows = dict()
        cls.flows[cls.pg0] = [cls.pg1]
        cls.flows[cls.pg1] = [cls.pg0]

        # packet sizes
        cls.pg_if_packet_sizes = [64, 512, 1518]  # , 9018]

        # setup all interfaces
        for i in cls.pg_interfaces:
            i.admin_up()
            i.config_ip4()
            i.resolve_arp()

        cls.vxlan = cls.vapi.vxlan_add_del_tunnel(
            src_addr=cls.pg2.local_ip4n,
            dst_addr=cls.pg2.remote_ip4n,
            vni=1111,
            is_add=1)

    def setUp(self):
        super(TestSpan, self).setUp()
        self.reset_packet_infos()

    def tearDown(self):
        super(TestSpan, self).tearDown()
        if not self.vpp_dead:
            self.logger.info(self.vapi.ppcli("show interface span"))

    def xconnect(self, a, b, is_add=1):
        self.vapi.sw_interface_set_l2_xconnect(a, b, enable=is_add)
        self.vapi.sw_interface_set_l2_xconnect(b, a, enable=is_add)

    def bridge(self, sw_if_index, is_add=1):
        self.vapi.sw_interface_set_l2_bridge(
            sw_if_index, bd_id=self.bd_id, enable=is_add)

    def _remove_tag(self, packet, vlan, tag_type):
        self.assertEqual(packet.type, tag_type)
        payload = packet.payload
        self.assertEqual(payload.vlan, vlan)
        inner_type = payload.type
        payload = payload.payload
        packet.remove_payload()
        packet.add_payload(payload)
        packet.type = inner_type

    def remove_tags(self, packet, tags):
        for t in tags:
            self._remove_tag(packet, t.vlan, t.dot1)
        return packet

    def decap_gre(self, pkt):
        """
        Decapsulate the original payload frame by removing GRE header
        """
        self.assertEqual(pkt[Ether].src, self.pg2.local_mac)
        self.assertEqual(pkt[Ether].dst, self.pg2.remote_mac)

        self.assertEqual(pkt[IP].src, self.pg2.local_ip4)
        self.assertEqual(pkt[IP].dst, self.pg2.remote_ip4)

        return pkt[GRE].payload

    def decap_erspan(self, pkt, session):
        """
        Decapsulate the original payload frame by removing ERSPAN header
        """
        self.assertEqual(pkt[Ether].src, self.pg2.local_mac)
        self.assertEqual(pkt[Ether].dst, self.pg2.remote_mac)

        self.assertEqual(pkt[IP].src, self.pg2.local_ip4)
        self.assertEqual(pkt[IP].dst, self.pg2.remote_ip4)

        self.assertEqual(pkt[ERSPAN].ver, 1)
        self.assertEqual(pkt[ERSPAN].vlan, 0)
        self.assertEqual(pkt[ERSPAN].cos, 0)
        self.assertEqual(pkt[ERSPAN].en, 3)
        self.assertEqual(pkt[ERSPAN].t, 0)
        self.assertEqual(pkt[ERSPAN].session_id, session)
        self.assertEqual(pkt[ERSPAN].reserved, 0)
        self.assertEqual(pkt[ERSPAN].index, 0)

        return pkt[ERSPAN].payload

    def decap_vxlan(self, pkt):
        """
        Decapsulate the original payload frame by removing VXLAN header
        """
        self.assertEqual(pkt[Ether].src, self.pg2.local_mac)
        self.assertEqual(pkt[Ether].dst, self.pg2.remote_mac)

        self.assertEqual(pkt[IP].src, self.pg2.local_ip4)
        self.assertEqual(pkt[IP].dst, self.pg2.remote_ip4)

        return pkt[VXLAN].payload

    def create_stream(self, src_if, packet_sizes, do_dot1=False, bcast=False):
        pkts = []
        dst_if = self.flows[src_if][0]
        dst_mac = src_if.remote_mac
        if bcast:
            dst_mac = "ff:ff:ff:ff:ff:ff"

        for i in range(0, self.pkts_per_burst):
            payload = "span test"
            size = packet_sizes[(i / 2) % len(packet_sizes)]
            p = (Ether(src=src_if.local_mac, dst=dst_mac) /
                 IP(src=src_if.remote_ip4, dst=dst_if.remote_ip4) /
                 UDP(sport=10000 + src_if.sw_if_index * 1000 + i, dport=1234) /
                 Raw(payload))
            if do_dot1:
                p = self.sub_if.add_dot1_layer(p)
            self.extend_packet(p, size)
            pkts.append(p)
        return pkts

    def verify_capture(self, cap1, cap2):
        self.assertEqual(len(cap1), len(cap2),
                         "Different number of sent and mirrored packets :"
                         "%u != %u" % (len(cap1), len(cap2)))

        pkts1 = [(pkt[Ether] / pkt[IP] / pkt[UDP]) for pkt in cap1]
        pkts2 = [(pkt[Ether] / pkt[IP] / pkt[UDP]) for pkt in cap2]

        self.assertEqual(pkts1.sort(), pkts2.sort())

    def test_device_span(self):
        """ SPAN device rx mirror """

        # Create bi-directional cross-connects between pg0 and pg1
        self.xconnect(self.pg0.sw_if_index, self.pg1.sw_if_index)
        # Create incoming packet streams for packet-generator interfaces
        pkts = self.create_stream(self.pg0, self.pg_if_packet_sizes)
        self.pg0.add_stream(pkts)

        # Enable SPAN on pg0 (mirrored to pg2)
        self.vapi.sw_interface_span_enable_disable(
            self.pg0.sw_if_index, self.pg2.sw_if_index)

        self.logger.info(self.vapi.ppcli("show interface span"))
        # Enable packet capturing and start packet sending
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Verify packets outgoing packet streams on mirrored interface (pg2)
        n_pkts = len(pkts)
        pg1_pkts = self.pg1.get_capture(n_pkts)
        pg2_pkts = self.pg2.get_capture(n_pkts)

        # Disable SPAN on pg0 (mirrored to pg2)
        self.vapi.sw_interface_span_enable_disable(
            self.pg0.sw_if_index, self.pg2.sw_if_index, state=0)
        self.xconnect(self.pg0.sw_if_index, self.pg1.sw_if_index, is_add=0)

        self.verify_capture(pg1_pkts, pg2_pkts)

    def test_span_l2_rx(self):
        """ SPAN l2 rx mirror """

        self.sub_if.admin_up()

        self.bridge(self.pg2.sw_if_index)
        # Create bi-directional cross-connects between pg0 subif and pg1
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index)
        # Create incoming packet streams for packet-generator interfaces
        pkts = self.create_stream(
            self.pg0, self.pg_if_packet_sizes, do_dot1=True)
        self.pg0.add_stream(pkts)

        # Enable SPAN on pg0 (mirrored to pg2)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.pg2.sw_if_index, is_l2=1)

        self.logger.info(self.vapi.ppcli("show interface span"))
        # Enable packet capturing and start packet sending
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Verify packets outgoing packet streams on mirrored interface (pg2)
        pg2_expected = len(pkts)
        pg1_pkts = self.pg1.get_capture(pg2_expected)
        pg2_pkts = self.pg2.get_capture(pg2_expected)
        self.bridge(self.pg2.sw_if_index, is_add=0)

        # Disable SPAN on pg0 (mirrored to pg2)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.pg2.sw_if_index, state=0, is_l2=1)
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=0)

        self.verify_capture(pg1_pkts, pg2_pkts)

    def test_span_l2_rx_dst_vxlan(self):
        """ SPAN l2 rx mirror into vxlan """

        self.sub_if.admin_up()
        self.vapi.sw_interface_set_flags(self.vxlan.sw_if_index,
                                         admin_up_down=1)

        self.bridge(self.vxlan.sw_if_index, is_add=1)
        # Create bi-directional cross-connects between pg0 subif and pg1
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index)
        # Create incoming packet streams for packet-generator interfaces
        pkts = self.create_stream(
            self.pg0, self.pg_if_packet_sizes, do_dot1=True)
        self.pg0.add_stream(pkts)

        # Enable SPAN on pg0 sub if (mirrored to vxlan)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.vxlan.sw_if_index, is_l2=1)

        self.logger.info(self.vapi.ppcli("show interface span"))
        # Enable packet capturing and start packet sending
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Verify packets outgoing packet streams on mirrored interface (pg2)
        n_pkts = len(pkts)
        pg1_pkts = self.pg1.get_capture(n_pkts)
        pg2_pkts = [self.decap_vxlan(p) for p in self.pg2.get_capture(n_pkts)]

        self.bridge(self.vxlan.sw_if_index, is_add=0)
        # Disable SPAN on pg0 sub if (mirrored to vxlan)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.vxlan.sw_if_index, state=0, is_l2=1)
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=0)
        self.verify_capture(pg1_pkts, pg2_pkts)

    def test_span_l2_rx_dst_gre_erspan(self):
        """ SPAN l2 rx mirror into gre-erspan """

        self.sub_if.admin_up()

        gre_if = VppGreInterface(self, self.pg2.local_ip4,
                                 self.pg2.remote_ip4,
                                 type=2,
                                 session=543)

        gre_if.add_vpp_config()
        gre_if.admin_up()

        self.bridge(gre_if.sw_if_index)
        # Create bi-directional cross-connects between pg0 and pg1
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=1)

        # Create incoming packet streams for packet-generator interfaces
        pkts = self.create_stream(
            self.pg0, self.pg_if_packet_sizes, do_dot1=True)
        self.pg0.add_stream(pkts)

        # Enable SPAN on pg0 sub if (mirrored to gre-erspan)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, gre_if.sw_if_index, is_l2=1)

        # Enable packet capturing and start packet sending
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Verify packets outgoing packet streams on mirrored interface (pg2)
        n_pkts = len(pkts)
        pg1_pkts = self.pg1.get_capture(n_pkts)
        pg2_pkts = self.pg2.get_capture(n_pkts)

        def decap(p): return self.decap_erspan(p, session=543)
        pg2_decaped = [decap(p) for p in pg2_pkts]

        self.bridge(gre_if.sw_if_index, is_add=0)

        # Disable SPAN on pg0 sub if
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, gre_if.sw_if_index, state=0, is_l2=1)
        gre_if.remove_vpp_config()
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=0)

        self.verify_capture(pg1_pkts, pg2_decaped)

    def test_span_l2_rx_dst_gre_subif_vtr(self):
        """ SPAN l2 rx mirror into gre-subif+vtr """

        self.sub_if.admin_up()

        gre_if = VppGreInterface(self, self.pg2.local_ip4,
                                 self.pg2.remote_ip4,
                                 type=1)

        gre_if.add_vpp_config()
        gre_if.admin_up()

        gre_sub_if = VppDot1QSubint(self, gre_if, 500)
        gre_sub_if.set_vtr(L2_VTR_OP.L2_POP_1, tag=500)
        gre_sub_if.admin_up()

        self.bridge(gre_sub_if.sw_if_index)
        # Create bi-directional cross-connects between pg0 and pg1
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=1)

        # Create incoming packet streams for packet-generator interfaces
        pkts = self.create_stream(
            self.pg0, self.pg_if_packet_sizes, do_dot1=True)
        self.pg0.add_stream(pkts)

        # Enable SPAN on pg0 sub if (mirrored to gre sub if)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, gre_sub_if.sw_if_index, is_l2=1)

        # Enable packet capturing and start packet sending
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Verify packets outgoing packet streams on mirrored interface (pg2)
        n_pkts = len(pkts)
        pg1_pkts = self.pg1.get_capture(n_pkts)
        pg2_pkts = self.pg2.get_capture(n_pkts)

        def decap(p): return self.remove_tags(
            self.decap_gre(p), [Tag(dot1=DOT1Q, vlan=500)])
        pg2_decaped = [decap(p) for p in pg2_pkts]

        self.bridge(gre_sub_if.sw_if_index, is_add=0)

        # Disable SPAN on pg0 sub if
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, gre_sub_if.sw_if_index, state=0, is_l2=1)
        gre_if.remove_vpp_config()
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=0)

        self.verify_capture(pg1_pkts, pg2_decaped)

    def test_span_l2_rx_dst_1q_vtr(self):
        """ SPAN l2 rx mirror into 1q subif+vtr """

        self.sub_if.admin_up()
        self.vlan_sub_if.admin_up()

        self.bridge(self.vlan_sub_if.sw_if_index)
        # Create bi-directional cross-connects between pg0 and pg1
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=1)

        # Create incoming packet streams for packet-generator interfaces
        pkts = self.create_stream(
            self.pg0, self.pg_if_packet_sizes, do_dot1=True)
        self.pg0.add_stream(pkts)

        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.vlan_sub_if.sw_if_index, is_l2=1)

        # Enable packet capturing and start packet sending
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Verify packets outgoing packet streams on mirrored interface (pg2)
        n_pkts = len(pkts)
        pg1_pkts = self.pg1.get_capture(n_pkts)
        pg2_pkts = self.pg2.get_capture(n_pkts)
        pg2_untagged = [self.remove_tags(p, [Tag(dot1=DOT1Q, vlan=300)])
                        for p in pg2_pkts]

        self.bridge(self.vlan_sub_if.sw_if_index, is_add=0)
        # Disable SPAN on pg0 sub if (mirrored to vxlan)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.vlan_sub_if.sw_if_index, state=0,
            is_l2=1)
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=0)

        self.verify_capture(pg1_pkts, pg2_untagged)

    def test_span_l2_rx_dst_1ad_vtr(self):
        """ SPAN l2 rx mirror into 1ad subif+vtr """

        self.sub_if.admin_up()
        self.qinq_sub_if.admin_up()

        self.bridge(self.qinq_sub_if.sw_if_index)
        # Create bi-directional cross-connects between pg0 and pg1
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=1)

        # Create incoming packet streams for packet-generator interfaces
        pkts = self.create_stream(
            self.pg0, self.pg_if_packet_sizes, do_dot1=True)
        self.pg0.add_stream(pkts)

        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.qinq_sub_if.sw_if_index, is_l2=1)

        # Enable packet capturing and start packet sending
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Verify packets outgoing packet streams on mirrored interface (pg2)
        n_pkts = len(pkts)
        pg1_pkts = self.pg1.get_capture(n_pkts)
        pg2_pkts = self.pg2.get_capture(n_pkts)
        pg2_untagged = [self.remove_tags(p, [Tag(dot1=DOT1AD, vlan=400),
                                             Tag(dot1=DOT1Q, vlan=500)])
                        for p in pg2_pkts]

        self.bridge(self.qinq_sub_if.sw_if_index, is_add=0)
        # Disable SPAN on pg0 sub if (mirrored to vxlan)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.qinq_sub_if.sw_if_index, state=0,
            is_l2=1)
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=0)

        self.verify_capture(pg1_pkts, pg2_untagged)

    def test_l2_tx_span(self):
        """ SPAN l2 tx mirror """

        self.sub_if.admin_up()
        self.bridge(self.pg2.sw_if_index)
        # Create bi-directional cross-connects between pg0 and pg1
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index)
        # Create incoming packet streams for packet-generator interfaces
        pkts = self.create_stream(
            self.pg0, self.pg_if_packet_sizes, do_dot1=True)
        self.pg0.add_stream(pkts)

        # Enable SPAN on pg1 (mirrored to pg2)
        self.vapi.sw_interface_span_enable_disable(
            self.pg1.sw_if_index, self.pg2.sw_if_index, is_l2=1, state=2)

        self.logger.info(self.vapi.ppcli("show interface span"))
        # Enable packet capturing and start packet sending
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Verify packets outgoing packet streams on mirrored interface (pg2)
        n_pkts = len(pkts)
        pg1_pkts = self.pg1.get_capture(n_pkts)
        pg2_pkts = self.pg2.get_capture(n_pkts)
        self.bridge(self.pg2.sw_if_index, is_add=0)
        # Disable SPAN on pg0 (mirrored to pg2)
        self.vapi.sw_interface_span_enable_disable(
            self.pg1.sw_if_index, self.pg2.sw_if_index, state=0, is_l2=1)
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=0)

        self.verify_capture(pg1_pkts, pg2_pkts)

    def test_l2_rx_tx_span(self):
        """ SPAN l2 rx tx mirror """

        self.sub_if.admin_up()
        self.bridge(self.pg2.sw_if_index)
        # Create bi-directional cross-connects between pg0 and pg1
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index)

        # Create incoming packet streams for packet-generator interfaces
        pg0_pkts = self.create_stream(
            self.pg0, self.pg_if_packet_sizes, do_dot1=True)
        self.pg0.add_stream(pg0_pkts)
        pg1_pkts = self.create_stream(
            self.pg1, self.pg_if_packet_sizes, do_dot1=False)
        self.pg1.add_stream(pg1_pkts)

        # Enable SPAN on pg0 (mirrored to pg2)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.pg2.sw_if_index, is_l2=1, state=3)
        self.logger.info(self.vapi.ppcli("show interface span"))

        # Enable packet capturing and start packet sending
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Verify packets outgoing packet streams on mirrored interface (pg2)
        pg0_expected = len(pg1_pkts)
        pg1_expected = len(pg0_pkts)
        pg2_expected = pg0_expected + pg1_expected

        pg0_pkts = self.pg0.get_capture(pg0_expected)
        pg1_pkts = self.pg1.get_capture(pg1_expected)
        pg2_pkts = self.pg2.get_capture(pg2_expected)

        self.bridge(self.pg2.sw_if_index, is_add=0)
        # Disable SPAN on pg0 (mirrored to pg2)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.pg2.sw_if_index, state=0, is_l2=1)
        self.xconnect(self.sub_if.sw_if_index, self.pg1.sw_if_index, is_add=0)

        self.verify_capture(pg0_pkts + pg1_pkts, pg2_pkts)

    def test_l2_bcast_mirror(self):
        """ SPAN l2 broadcast mirror """

        self.sub_if.admin_up()
        self.bridge(self.pg2.sw_if_index)

        # Create bi-directional cross-connects between pg0 and pg1
        self.vapi.sw_interface_set_l2_bridge(
            self.sub_if.sw_if_index, bd_id=99, enable=1)
        self.vapi.sw_interface_set_l2_bridge(
            self.pg1.sw_if_index, bd_id=99, enable=1)

        # Create incoming packet streams for packet-generator interfaces
        pg0_pkts = self.create_stream(
            self.pg0, self.pg_if_packet_sizes, do_dot1=True, bcast=True)
        self.pg0.add_stream(pg0_pkts)
        pg1_pkts = self.create_stream(
            self.pg1, self.pg_if_packet_sizes, do_dot1=False, bcast=True)
        self.pg1.add_stream(pg1_pkts)

        # Enable SPAN on pg0 (mirrored to pg2)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.pg2.sw_if_index, is_l2=1, state=3)
        self.logger.info(self.vapi.ppcli("show interface span"))

        # Enable packet capturing and start packet sending
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Verify packets outgoing packet streams on mirrored interface (pg2)
        pg0_expected = len(pg1_pkts)
        pg1_expected = len(pg0_pkts)
        pg2_expected = pg0_expected + pg1_expected

        pg0_pkts = self.pg0.get_capture(pg0_expected)
        pg1_pkts = self.pg1.get_capture(pg1_expected)
        pg2_pkts = self.pg2.get_capture(pg2_expected)

        self.bridge(self.pg2.sw_if_index, is_add=0)
        self.vapi.sw_interface_set_l2_bridge(
            self.sub_if.sw_if_index, bd_id=99, enable=0)
        self.vapi.sw_interface_set_l2_bridge(
            self.pg1.sw_if_index, bd_id=99, enable=0)
        # Disable SPAN on pg0 (mirrored to pg2)
        self.vapi.sw_interface_span_enable_disable(
            self.sub_if.sw_if_index, self.pg2.sw_if_index, state=0, is_l2=1)

        self.verify_capture(pg0_pkts + pg1_pkts, pg2_pkts)


if __name__ == '__main__':
    unittest.main(testRunner=VppTestRunner)