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[dhcp_relay] Verify configured DHCP relay hop limits #26321

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[dhcp_relay] Verify configured DHCP relay hop limits #26321

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48 changes: 40 additions & 8 deletions ansible/roles/test/files/ptftests/py3/dhcp_relay_test.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -174,6 +174,9 @@
self.portchannels_ip_list = self.test_params.get('portchannels_ip_list', None)
self.agent_relay_mode = self.test_params.get('agent_relay_mode', None)
self.max_hop_count = self.test_params.get('max_hop_count', None)
self.incoming_hop_count = self.test_params.get('incoming_hop_count', None)
self.client_giaddr = self.test_params.get('client_giaddr', self.switch_loopback_ip)
self.expected_forward = self.test_params.get('expected_forward', None)
self.client_vrf = self.test_params.get('client_vrf', None)
self.dhcpv4_disable_flag = self.test_params.get('dhcpv4_disable_flag', None)
if self.relay_agent == "sonic-relay-agent":
Expand Down Expand Up @@ -299,8 +302,11 @@
discover_packet[scapy.Ether].dst = self.uplink_mac
discover_packet[scapy.IP].src = self.client_ip
discover_packet[scapy.IP].dst = self.switch_loopback_ip
discover_packet[scapy.BOOTP].hops = self.max_hop_count if self.max_hop_count == self.MAX_HOP_COUNT else 1
discover_packet[scapy.BOOTP].giaddr = self.switch_loopback_ip
discover_packet[scapy.BOOTP].hops = (
self.incoming_hop_count if self.incoming_hop_count is not None
else self.max_hop_count if self.max_hop_count == self.MAX_HOP_COUNT else 1
)
discover_packet[scapy.BOOTP].giaddr = self.client_giaddr
discover_packet[scapy.DHCP].options.insert(
discover_packet[scapy.DHCP].options.index("end"),
(82, relay_option82)
Expand Down Expand Up @@ -337,8 +343,10 @@
else:
source_ip = self.portchannels_ip_list[0]

if ((self.link_selection and self.source_interface) or
self.server_vrf or self.dual_tor or self.agent_relay_mode):
if self.incoming_hop_count is not None:
giaddr = self.client_giaddr
elif ((self.link_selection and self.source_interface) or
self.server_vrf or self.dual_tor or self.agent_relay_mode):
giaddr = self.switch_loopback_ip
elif self.server_id_override or not self.dual_tor:
giaddr = self.relay_iface_ip
Expand Down Expand Up @@ -380,7 +388,9 @@
(82, self.option82),
('end')]

if self.max_hop_count == self.MAX_HOP_COUNT:
if self.incoming_hop_count is not None:
hops = self.incoming_hop_count + 1
elif self.max_hop_count == self.MAX_HOP_COUNT:
hops = 17
elif self.agent_relay_mode:
hops = 2
Expand Down Expand Up @@ -1200,14 +1210,36 @@
self.check_relayed_pkts_on_server_side(masked_request, dhcp_request_relayed, "Inform")

def check_relayed_pkts_on_server_side(self, mask, pkt, packet_type):
logger.info("Expect receiving {} packets from port [{}]".format(packet_type, self.server_port_indices))

Check failure

Code scanning / CodeQL

Potentially uninitialized local variable Error test

Local variable 'expected_forward' may be used before it is initialized.
log_dhcp_packet_info(pkt)
num_expected_packets = self.num_dhcp_servers
if self.agent_relay_mode == "discard" or self.dhcpv4_disable_flag or self.max_hop_count == self.MAX_HOP_COUNT:
# Expected result: No packet sent
if self.expected_forward is None:
expected_forward = not (
self.agent_relay_mode == "discard"
or self.dhcpv4_disable_flag
or self.max_hop_count == self.MAX_HOP_COUNT
)
else:
expected_forward = self.expected_forward
if expected_forward:
packet_mask = mask
else:
num_expected_packets = 0
unexpected_packet = (
scapy.Ether(src=self.uplink_mac)
/ scapy.IP()
/ scapy.UDP(sport=self.DHCP_SERVER_PORT, dport=self.DHCP_SERVER_PORT)
)
packet_mask = Mask(unexpected_packet)
packet_mask.set_do_not_care_scapy(scapy.Ether, "dst")
for field in ("version", "ihl", "tos", "len", "id", "flags",
"frag", "ttl", "chksum", "src", "dst", "options"):
packet_mask.set_do_not_care_scapy(scapy.IP, field)
packet_mask.set_do_not_care_scapy(scapy.UDP, "chksum")
packet_mask.set_do_not_care_scapy(scapy.UDP, "len")
packet_mask.set_ignore_extra_bytes()
captured_count = testutils.count_matched_packets_all_ports(
self, mask, self.server_port_indices)
self, packet_mask, self.server_port_indices)
self.assertTrue(captured_count == num_expected_packets,
"Failed: %s packet counts are not equal %d != %d"
% (packet_type, captured_count, num_expected_packets))
Expand Down
20 changes: 16 additions & 4 deletions tests/dhcp_relay/test_dhcpv4_relay.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -79,6 +79,7 @@ def _restore_interface_ip_entries(duthost, saved_entries):
CLIENT_VRF_NAME = "Vrf01" # Global macro for Client VRF
MAX_HOP_COUNT = 16
CONFIG_HOP_COUNT = 2
DOWNSTREAM_RELAY_IP = '192.0.2.1' # TEST-NET-1; synthetic downstream relay

logger = logging.getLogger(__name__)

Expand Down Expand Up @@ -855,13 +856,21 @@ def test_dhcp_relay_with_different_non_default_vrf(
duthost.shell("sudo config save -y")


@pytest.mark.parametrize("max_hop_count", [CONFIG_HOP_COUNT, MAX_HOP_COUNT])
@pytest.mark.parametrize(
"max_hop_count,incoming_hop_count,expected_forward",
[
(CONFIG_HOP_COUNT, 1, True),
(CONFIG_HOP_COUNT, CONFIG_HOP_COUNT, False),
(MAX_HOP_COUNT, MAX_HOP_COUNT - 1, True),
(MAX_HOP_COUNT, MAX_HOP_COUNT, False),
]
)
def test_dhcp_max_hop_count(ptfhost, dut_dhcp_relay_data, validate_dut_routes_exist, testing_config,
setup_standby_ports_on_rand_unselected_tor,
rand_unselected_dut,
toggle_all_simulator_ports_to_rand_selected_tor_m, relay_agent, # noqa: F811
max_hop_count):

max_hop_count, incoming_hop_count, expected_forward):
"""Verify configured hop limits distinguish forwarding from dropping."""
testing_mode, duthost = testing_config

try:
Expand Down Expand Up @@ -901,9 +910,12 @@ def test_dhcp_max_hop_count(ptfhost, dut_dhcp_relay_data, validate_dut_routes_ex
"relay_agent": relay_agent,
"agent_relay_mode": "append",
"max_hop_count": max_hop_count,
"incoming_hop_count": incoming_hop_count,
"client_giaddr": DOWNSTREAM_RELAY_IP,
"expected_forward": expected_forward,
"downlink_vlan_iface_name": str(dhcp_relay['downlink_vlan_iface']['name']),
},
log_file="/tmp/test_dhcp_relay_agent_mode.log",
log_file="/tmp/test_dhcp_max_hop_count.log",
is_python3=True
)

Expand Down
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