[dhcp_relay] DHCPv6 automatic test (#3565)

What is the motivation for this PR?
Add DHCPv6 automatic test infrastructure and PTF test.

How did you do it?
Enhance the minigraph_facts.py and minigraph_dpg.j2 to support DHCPv6 instances.
Add DHCPv6 servers to lab.yml file.
This will deploy on a DUT DHCPv6 servers on regression run.
Develop a test with 3 test cases:

test_dhcp_relay_default
test_dhcp_relay_after_link_flap
test_dhcp_relay_start_with_uplinks_down
Develop a PTF runner test to simulate the traffic according to the test case from sonic-mgmt.

How did you verify/test it?
Use testbed-cli.sh to generate and deploy a minigraph with DHCPv6 instances on a switch.
Run the test.
This test depends on PR: [dhcp_relay] DHCP relay support for IPv6 sonic-buildimage#7772

Supported testbed topology if it's a new test case?
T0

Signed-off-by: Shlomi Bitton <shlomibi@nvidia.com>

ansible/group_vars/lab/lab.yml

@@ -39,6 +39,9 @@ snmp_servers: ['10.0.0.9']
 # dhcp relay servers
 dhcp_servers: ['192.0.0.1', '192.0.0.2', '192.0.0.3', '192.0.0.4']
 
+# dhcpv6 relay servers
+dhcpv6_servers: ['fc02:2000::1', 'fc02:2000::2', 'fc02:2000::3', 'fc02:2000::4']
+
 # snmp variables
 snmp_rocommunity: public
 snmp_location: testlab

ansible/library/minigraph_facts.py

@@ -363,6 +363,7 @@ def parse_dpg(dpg, hname):
 
         vlanintfs = child.find(str(QName(ns, "VlanInterfaces")))
         dhcp_servers = []
+        dhcpv6_servers = []
         vlans = {}
         for vintf in vlanintfs.findall(str(QName(ns, "VlanInterface"))):
             vintfname = vintf.find(str(QName(ns, "Name"))).text
@@ -375,6 +376,12 @@ def parse_dpg(dpg, hname):
             else:
                 vlandhcpservers = ""
             dhcp_servers = vlandhcpservers.split(";")
+            vintf_node = vintf.find(str(QName(ns, "Dhcpv6Relays")))
+            if vintf_node is not None and vintf_node.text is not None:
+                vlandhcpservers = vintf_node.text
+            else:
+                vlandhcpservers = ""
+            dhcpv6_servers = vlandhcpservers.split(";")
             for i, member in enumerate(vmbr_list):
                 # Skip PortChannel inside Vlan
                 if member in pcs:
@@ -402,7 +409,7 @@ def parse_dpg(dpg, hname):
             if acl_intfs:
                 acls[aclname] = acl_intfs
 
-        return intfs, lo_intfs, mgmt_intf, vlans, pcs, acls, dhcp_servers
+        return intfs, lo_intfs, mgmt_intf, vlans, pcs, acls, dhcp_servers, dhcpv6_servers
     return None, None, None, None, None, None, None
 
 def parse_cpg(cpg, hname):
@@ -578,6 +585,7 @@ def parse_xml(filename, hostname, asic_name=None):
     hostname = None
     syslog_servers = []
     dhcp_servers = []
+    dhcpv6_servers = []
     ntp_servers = []
     mgmt_routes = []
     bgp_peers_with_range = []
@@ -608,7 +616,7 @@ def parse_xml(filename, hostname, asic_name=None):
     for child in root:
         if asic_name is None:
             if child.tag == str(QName(ns, "DpgDec")):
-                (intfs, lo_intfs, mgmt_intf, vlans, pcs, acls, dhcp_servers) = parse_dpg(child, hostname)
+                (intfs, lo_intfs, mgmt_intf, vlans, pcs, acls, dhcp_servers, dhcpv6_servers) = parse_dpg(child, hostname)
             elif child.tag == str(QName(ns, "CpgDec")):
                 (bgp_sessions, bgp_asn, bgp_peers_with_range) = parse_cpg(child, hostname)
             elif child.tag == str(QName(ns, "PngDec")):
@@ -619,7 +627,7 @@ def parse_xml(filename, hostname, asic_name=None):
                 (syslog_servers, ntp_servers, mgmt_routes, deployment_id) = parse_meta(child, hostname)
         else:
             if child.tag == str(QName(ns, "DpgDec")):
-                (intfs, lo_intfs, mgmt_intf, vlans, pcs, acls, dhcp_servers) = parse_dpg(child, asic_name)
+                (intfs, lo_intfs, mgmt_intf, vlans, pcs, acls, dhcp_servers, dhcpv6_servers) = parse_dpg(child, asic_name)
                 host_lo_intfs = parse_host_loopback(child, hostname)
             elif child.tag == str(QName(ns, "CpgDec")):
                 (bgp_sessions, bgp_asn, bgp_peers_with_range) = parse_cpg(child, asic_name)
@@ -700,6 +708,7 @@ def parse_xml(filename, hostname, asic_name=None):
             results['minigraph_mgmt'] = get_mgmt_info(devices, mgmt_dev, mgmt_port)
     results['syslog_servers'] = syslog_servers
     results['dhcp_servers'] = dhcp_servers
+    results['dhcpv6_servers'] = dhcpv6_servers
     results['ntp_servers'] = ntp_servers
     results['forced_mgmt_routes'] = mgmt_routes
     results['deployment_id'] = deployment_id

ansible/roles/test/files/ptftests/dhcpv6_relay_test.py

@@ -0,0 +1,306 @@
+import ast
+import subprocess
+
+# Packet Test Framework imports
+import ptf
+import ptf.packet as packet
+import ptf.testutils as testutils
+from ptf import config
+from ptf.base_tests import BaseTest
+from ptf.mask import Mask
+
+IPv6 = scapy.layers.inet6.IPv6
+
+class DataplaneBaseTest(BaseTest):
+    def __init__(self):
+        BaseTest.__init__(self)
+
+    def setUp(self):
+        self.dataplane = ptf.dataplane_instance
+        self.dataplane.flush()
+        if config["log_dir"] is not None:
+            filename = os.path.join(config["log_dir"], str(self)) + ".pcap"
+            self.dataplane.start_pcap(filename)
+
+    def tearDown(self):
+        if config["log_dir"] is not None:
+            self.dataplane.stop_pcap()
+
+"""
+ This test simulates a new host booting up on the VLAN network of a ToR and
+ requesting an IPv6 address via DHCPv6. Setup is as follows:
+  - DHCP client is simulated by listening/sending on an interface connected to VLAN of ToR.
+  - DHCP server is simulated by listening/sending on injected PTF interfaces which link
+    ToR to leaves. This way we can listen for traffic sent from DHCP relay out to would-be DHCPv6 servers
+
+ This test performs the following functionality:
+   1.) Simulated client broadcasts a DHCPv6 SOLICIT message.
+   2.) Verify DHCP relay running on ToR receives the DHCPv6 SOLICIT message and send a DHCPv6 RELAY-FORWARD
+       message encapsulating the client DHCPv6 SOLICIT message and relays it to all of its known DHCP servers.
+   3.) Simulate DHCPv6 RELAY-REPLY message send from a DHCP server to the ToR encapsulating DHCPv6 ADVERTISE message.
+   4.) Verify DHCP relay receives the DHCPv6 RELAY-REPLY message decapsulate it and forwards DHCPv6 ADVERTISE
+       message to our simulated client.
+   5.) Simulated client broadcasts a DHCPv6 REQUEST message.
+   6.) Verify DHCP relay running on ToR receives the DHCPv6 REQUEST message and send a DHCPv6 RELAY-FORWARD
+       message encapsulating the client DHCPv6 REQUEST message and relays it to all of its known DHCP servers.
+   7.) Simulate DHCPv6 RELAY-REPLY message send from a DHCP server to the ToR encapsulating DHCPv6 REPLY message.
+   8.) Verify DHCP relay receives the DHCPv6 RELAY-REPLY message decapsulate it and forwards DHCPv6 REPLY
+       message to our simulated client.
+
+"""
+
+class DHCPTest(DataplaneBaseTest):
+
+    BROADCAST_MAC = '33:33:00:01:00:02'
+    BROADCAST_IP = 'ff02::1:2'
+    DHCP_CLIENT_PORT = 546
+    DHCP_SERVER_PORT = 547
+
+    def __init__(self):
+        self.test_params = testutils.test_params_get()
+        self.client_port_index = int(self.test_params['client_port_index'])
+        self.client_link_local =  self.generate_client_interace_ipv6_link_local_address(self.client_port_index)
+
+        DataplaneBaseTest.__init__(self)
+
+    def setUp(self):
+        DataplaneBaseTest.setUp(self)
+        self.hostname = self.test_params['hostname']
+
+        # These are the interfaces we are injected into that link to out leaf switches
+        self.server_port_indices = ast.literal_eval(self.test_params['leaf_port_indices'])
+        self.num_dhcp_servers = int(self.test_params['num_dhcp_servers'])
+        self.assertTrue(self.num_dhcp_servers > 0,
+                "Error: This test requires at least one DHCP server to be specified!")
+
+        # We will simulate a responding DHCP server on the first interface in the provided set
+        self.server_ip = self.test_params['server_ip']
+
+        self.relay_iface_ip = self.test_params['relay_iface_ip']
+        self.relay_iface_mac = self.test_params['relay_iface_mac']
+        self.relay_link_local = self.test_params['relay_link_local']
+
+        self.vlan_ip = self.test_params['vlan_ip']
+
+        self.client_mac = self.dataplane.get_mac(0, self.client_port_index)
+
+    def generate_client_interace_ipv6_link_local_address(self, client_port_index):
+        # Shutdown and startup the client interface to generate a proper IPv6 link-local address
+        command = "ifconfig eth{} down".format(client_port_index)
+        proc = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE)
+        proc.communicate()
+
+        command = "ifconfig eth{} up".format(client_port_index)
+        proc = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE)
+        proc.communicate()
+
+        command = "ip addr show eth{} | grep inet6 | grep 'scope link' | awk '{{print $2}}' | cut -d '/' -f1".format(client_port_index)
+        proc = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE)
+        stdout, stderr = proc.communicate()
+
+        return stdout.strip()
+
+    def tearDown(self):
+        DataplaneBaseTest.tearDown(self)
+
+
+    """
+     Packet generation functions/wrappers
+
+    """
+
+    def create_dhcp_solicit_packet(self):
+
+        solicit_packet = Ether(src=self.client_mac, dst=self.BROADCAST_MAC)
+        solicit_packet /= IPv6(src=self.client_link_local, dst=self.BROADCAST_IP)
+        solicit_packet /= UDP(sport=self.DHCP_CLIENT_PORT, dport=self.DHCP_SERVER_PORT)
+        solicit_packet /= DHCP6_Solicit(trid=12345)
+
+        return solicit_packet
+
+    def create_dhcp_solicit_relay_forward_packet(self):
+
+        solicit_relay_forward_packet = Ether(src=self.relay_iface_mac)
+        solicit_relay_forward_packet /= IPv6()
+        solicit_relay_forward_packet /= UDP(sport=self.DHCP_SERVER_PORT, dport=self.DHCP_SERVER_PORT)
+        solicit_relay_forward_packet /= DHCP6_RelayForward(msgtype=12, linkaddr=self.vlan_ip, peeraddr=self.client_link_local)
+        solicit_relay_forward_packet /= DHCP6OptRelayMsg()
+        solicit_relay_forward_packet /= DHCP6_Solicit(trid=12345)
+
+        return solicit_relay_forward_packet
+
+    def create_dhcp_advertise_packet(self):
+
+        advertise_packet = Ether(src=self.relay_iface_mac, dst=self.client_mac)
+        advertise_packet /= IPv6(src=self.relay_link_local, dst=self.client_link_local)
+        advertise_packet /= UDP(sport=self.DHCP_SERVER_PORT, dport=self.DHCP_CLIENT_PORT)
+        advertise_packet /= DHCP6_Advertise(trid=12345)
+
+        return advertise_packet
+
+    def create_dhcp_advertise_relay_reply_packet(self):
+
+        advertise_relay_reply_packet = Ether(dst=self.relay_iface_mac)
+        advertise_relay_reply_packet /= IPv6(src=self.server_ip, dst=self.relay_iface_ip)
+        advertise_relay_reply_packet /= UDP(sport=self.DHCP_SERVER_PORT, dport=self.DHCP_SERVER_PORT)
+        advertise_relay_reply_packet /= DHCP6_RelayReply(msgtype=13, linkaddr=self.vlan_ip, peeraddr=self.client_link_local)
+        advertise_relay_reply_packet /= DHCP6OptRelayMsg()
+        advertise_relay_reply_packet /= DHCP6_Advertise(trid=12345)
+
+        return advertise_relay_reply_packet
+
+    def create_dhcp_request_packet(self):
+
+        request_packet = Ether(src=self.client_mac, dst=self.BROADCAST_MAC)
+        request_packet /= IPv6(src=self.client_link_local, dst=self.BROADCAST_IP)
+        request_packet /= UDP(sport=self.DHCP_CLIENT_PORT, dport=self.DHCP_SERVER_PORT)
+        request_packet /= DHCP6_Request(trid=12345)
+
+        return request_packet
+
+    def create_dhcp_request_relay_forward_packet(self):
+
+        request_relay_forward_packet = Ether(src=self.relay_iface_mac)
+        request_relay_forward_packet /= IPv6()
+        request_relay_forward_packet /= UDP(sport=self.DHCP_SERVER_PORT, dport=self.DHCP_SERVER_PORT)
+        request_relay_forward_packet /= DHCP6_RelayForward(msgtype=12, linkaddr=self.vlan_ip, peeraddr=self.client_link_local)
+        request_relay_forward_packet /= DHCP6OptRelayMsg()
+        request_relay_forward_packet /= DHCP6_Request(trid=12345)
+
+        return request_relay_forward_packet
+
+    def create_dhcp_reply_packet(self):
+
+        reply_packet = Ether(src=self.relay_iface_mac, dst=self.client_mac)
+        reply_packet /= IPv6(src=self.relay_link_local, dst=self.client_link_local)
+        reply_packet /= UDP(sport=self.DHCP_SERVER_PORT, dport=self.DHCP_CLIENT_PORT)
+        reply_packet /= DHCP6_Reply(trid=12345)
+
+        return reply_packet
+
+    def create_dhcp_reply_relay_reply_packet(self):
+
+        reply_relay_reply_packet = Ether(dst=self.relay_iface_mac)
+        reply_relay_reply_packet /= IPv6(src=self.server_ip, dst=self.relay_iface_ip)
+        reply_relay_reply_packet /= UDP(sport=self.DHCP_SERVER_PORT, dport=self.DHCP_SERVER_PORT)
+        reply_relay_reply_packet /= DHCP6_RelayReply(msgtype=13, linkaddr=self.vlan_ip, peeraddr=self.client_link_local)
+        reply_relay_reply_packet /= DHCP6OptRelayMsg()
+        reply_relay_reply_packet /= DHCP6_Reply(trid=12345)
+
+        return reply_relay_reply_packet
+
+
+    """
+     Send/receive functions
+
+    """
+
+    # Simulate client connecting on VLAN and broadcasting a DHCPv6 SOLICIT message
+    def client_send_solicit(self):
+        # Form and send DHCPv6 SOLICIT packet
+        solicit_packet = self.create_dhcp_solicit_packet()
+        testutils.send_packet(self, self.client_port_index, solicit_packet)
+
+    # Verify that the DHCP relay actually received and relayed the DHCPv6 SOLICIT message to all of
+    # its known DHCP servers.
+    def verify_relayed_solicit_relay_forward(self):
+        # Create a packet resembling a DHCPv6 RELAY-FORWARD encapsulating SOLICIT packet
+        solicit_relay_forward_packet = self.create_dhcp_solicit_relay_forward_packet()
+
+        # Mask off fields we don't care about matching
+        masked_packet = Mask(solicit_relay_forward_packet)
+        masked_packet.set_do_not_care_scapy(packet.Ether, "dst")
+        masked_packet.set_do_not_care_scapy(IPv6, "src")
+        masked_packet.set_do_not_care_scapy(IPv6, "dst")
+        masked_packet.set_do_not_care_scapy(IPv6, "fl")
+        masked_packet.set_do_not_care_scapy(IPv6, "tc")
+        masked_packet.set_do_not_care_scapy(IPv6, "plen")
+        masked_packet.set_do_not_care_scapy(IPv6, "nh")
+        masked_packet.set_do_not_care_scapy(packet.UDP, "chksum")
+        masked_packet.set_do_not_care_scapy(packet.UDP, "len")
+
+        # Count the number of these packets received on the ports connected to our leaves
+        solicit_count = testutils.count_matched_packets_all_ports(self, masked_packet, self.server_port_indices)
+        self.assertTrue(solicit_count >= 1,
+                "Failed: Solicit count of %d" % (solicit_count))
+
+    # Simulate a DHCP server sending a DHCPv6 RELAY-REPLY encapsulating ADVERTISE packet message to client.
+    # We do this by injecting a RELAY-REPLY encapsulating ADVERTISE message on the link connected to one
+    # of our leaf switches.
+    def server_send_advertise_relay_reply(self):
+        # Form and send DHCPv6 RELAY-REPLY encapsulating ADVERTISE packet
+        advertise_relay_reply_packet = self.create_dhcp_advertise_relay_reply_packet()
+        testutils.send_packet(self, self.server_port_indices[0], advertise_relay_reply_packet)
+
+    # Verify that the DHCPv6 ADVERTISE would be received by our simulated client
+    def verify_relayed_advertise(self):
+        # Create a packet resembling a DHCPv6 ADVERTISE packet
+        advertise_packet = self.create_dhcp_advertise_packet()
+
+        # Mask off fields we don't care about matching
+        masked_packet = Mask(advertise_packet)
+        masked_packet.set_do_not_care_scapy(IPv6, "fl")
+        masked_packet.set_do_not_care_scapy(packet.UDP, "chksum")
+        masked_packet.set_do_not_care_scapy(packet.UDP, "len")
+
+        # NOTE: verify_packet() will fail for us via an assert, so no need to check a return value here
+        testutils.verify_packet(self, masked_packet, self.client_port_index)
+
+    # Simulate our client sending a DHCPv6 REQUEST message
+    def client_send_request(self):
+        # Form and send DHCPv6 REQUEST packet
+        request_packet = self.create_dhcp_request_packet()
+        testutils.send_packet(self, self.client_port_index, request_packet)
+
+    # Verify that the DHCP relay actually received and relayed the DHCPv6 REQUEST message to all of
+    # its known DHCP servers.
+    def verify_relayed_request_relay_forward(self):
+        # Create a packet resembling a DHCPv6 RELAY-FORWARD encapsulating REQUEST packet
+        request_relay_forward_packet = self.create_dhcp_request_relay_forward_packet()
+
+        # Mask off fields we don't care about matching
+        masked_packet = Mask(request_relay_forward_packet)
+        masked_packet.set_do_not_care_scapy(packet.Ether, "dst")
+        masked_packet.set_do_not_care_scapy(IPv6, "src")
+        masked_packet.set_do_not_care_scapy(IPv6, "dst")
+        masked_packet.set_do_not_care_scapy(IPv6, "fl")
+        masked_packet.set_do_not_care_scapy(IPv6, "tc")
+        masked_packet.set_do_not_care_scapy(IPv6, "plen")
+        masked_packet.set_do_not_care_scapy(IPv6, "nh")
+        masked_packet.set_do_not_care_scapy(packet.UDP, "chksum")
+        masked_packet.set_do_not_care_scapy(packet.UDP, "len")
+
+        # Count the number of these packets received on the ports connected to our leaves
+        request_count = testutils.count_matched_packets_all_ports(self, masked_packet, self.server_port_indices)
+        self.assertTrue(request_count >= 1,
+                "Failed: Request count of %d" % (request_count))
+
+    # Simulate a DHCP server sending a DHCPv6 RELAY-REPLY encapsulating REPLY packet message to client.
+    def server_send_reply_relay_reply(self):
+        # Form and send DHCPv6 RELAY-REPLY encapsulating REPLY packet
+        reply_relay_reply_packet = self.create_dhcp_reply_relay_reply_packet()
+        testutils.send_packet(self, self.server_port_indices[0], reply_relay_reply_packet)
+
+    # Verify that the DHCPv6 REPLY would be received by our simulated client
+    def verify_relayed_reply(self):
+        # Create a packet resembling a DHCPv6 REPLY packet
+        reply_packet = self.create_dhcp_reply_packet()
+
+        # Mask off fields we don't care about matching
+        masked_packet = Mask(reply_packet)
+        masked_packet.set_do_not_care_scapy(IPv6, "fl")
+        masked_packet.set_do_not_care_scapy(packet.UDP, "chksum")
+        masked_packet.set_do_not_care_scapy(packet.UDP, "len")
+
+        # NOTE: verify_packet() will fail for us via an assert, so no need to check a return value here
+        testutils.verify_packet(self, masked_packet, self.client_port_index)
+
+    def runTest(self):
+        self.client_send_solicit()
+        self.verify_relayed_solicit_relay_forward()
+        self.server_send_advertise_relay_reply()
+        self.verify_relayed_advertise()
+        self.client_send_request()
+        self.verify_relayed_request_relay_forward()
+        self.server_send_reply_relay_reply()
+        self.verify_relayed_reply()

ansible/templates/minigraph_dpg.j2

@@ -130,6 +130,8 @@
 {% endif %}
 {% set dhcp_servers_str=';'.join(dhcp_servers) %}
           <DhcpRelays>{{ dhcp_servers_str }}</DhcpRelays>
+{% set dhcpv6_servers_str=';'.join(dhcpv6_servers) %}
+          <Dhcpv6Relays>{{ dhcpv6_servers_str }}</Dhcpv6Relays>
           <VlanID>{{ vlan_param['id'] }}</VlanID>
           <Tag>{{ vlan_param['tag'] }}</Tag>
           <Subnets>{{ vlan_param['prefix'] | ipaddr('network') }}/{{ vlan_param['prefix'] | ipaddr('prefix') }}</Subnets>