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#!/usr/bin/env python3
"""IP4 and IP6 MTU functional tests"""
#
# Add tests for:
# - sub interfaces
# - Verify that adjacencies inherit MTU correctly
# - Verify that sub-interfaces inherit MTU correctly
# - Different types of interfaces?
#
import unittest
from scapy.layers.inet6 import IPv6, Ether, IP, UDP, ICMPv6PacketTooBig
from scapy.layers.inet import ICMP
from framework import VppTestCase
from asfframework import VppTestRunner
from util import reassemble4
""" Test_mtu is a subclass of VPPTestCase classes.
MTU tests.
"""
class TestMTU(VppTestCase):
"""MTU Test Case"""
maxDiff = None
@classmethod
def setUpClass(cls):
super(TestMTU, cls).setUpClass()
cls.create_pg_interfaces(range(2))
cls.interfaces = list(cls.pg_interfaces)
@classmethod
def tearDownClass(cls):
super(TestMTU, cls).tearDownClass()
def setUp(self):
super(TestMTU, self).setUp()
for i in self.interfaces:
i.admin_up()
i.config_ip4()
i.config_ip6()
i.disable_ipv6_ra()
i.resolve_arp()
i.resolve_ndp()
def tearDown(self):
super(TestMTU, self).tearDown()
if not self.vpp_dead:
for i in self.pg_interfaces:
i.unconfig_ip4()
i.unconfig_ip6()
i.admin_down()
def validate(self, rx, expected):
self.assertTrue(bytes(rx), bytes(expected))
def validate_bytes(self, rx, expected):
self.assertEqual(rx, expected)
def payload(self, len):
return "x" * len
def get_mtu(self, sw_if_index):
rv = self.vapi.sw_interface_dump(sw_if_index=sw_if_index)
for i in rv:
if i.sw_if_index == sw_if_index:
return i.mtu[0]
return 0
def test_ip4_mtu(self):
"""IP4 MTU test"""
p_ether = Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
p_ip4 = IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4, flags="DF")
current_mtu = self.get_mtu(self.pg1.sw_if_index)
p_payload = UDP(sport=1234, dport=1234) / self.payload(current_mtu - 20 - 8)
p4 = p_ether / p_ip4 / p_payload
p4_reply = p_ip4 / p_payload
p4_reply.ttl -= 1
rx = self.send_and_expect(self.pg0, p4 * 11, self.pg1)
for p in rx:
self.validate(p[1], p4_reply)
# MTU
self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, [576, 0, 0, 0])
self.assertEqual(576, self.get_mtu(self.pg1.sw_if_index))
# Should fail. Too large MTU
p_icmp4 = ICMP(
type="dest-unreach",
code="fragmentation-needed",
nexthopmtu=576,
chksum=0x2DBB,
)
icmp4_reply = (
IP(src=self.pg0.local_ip4, dst=self.pg0.remote_ip4, ttl=255, len=576, id=0)
/ p_icmp4
/ p_ip4
/ p_payload
)
s = bytes(icmp4_reply)
icmp4_reply = s[0:576]
rx = self.send_and_expect_some(self.pg0, p4 * 11, self.pg0)
for p in rx:
self.validate_bytes(bytes(p[1]), icmp4_reply)
self.assert_error_counter_equal("/err/ip4-input/mtu_exceeded", 11)
# Now with DF off. Expect fragments.
# First go with 1500 byte packets.
p_payload = UDP(sport=1234, dport=1234) / self.payload(1500 - 20 - 8)
p4 = p_ether / p_ip4 / p_payload
p4.flags = 0
p4_reply = p_ip4 / p_payload
p4_reply.ttl = p_ip4.ttl - 1
p4_reply.flags = 0
p4_reply.id = 256
self.pg_enable_capture()
self.pg0.add_stream(p4 * 1)
self.pg_start()
rx = self.pg1.get_capture(3)
reass_pkt = reassemble4(rx)
self.validate(reass_pkt, p4_reply)
"""
# Now what happens with a 9K frame
p_payload = UDP(sport=1234, dport=1234) / self.payload(
current_mtu - 20 - 8)
p4 = p_ether / p_ip4 / p_payload
p4.flags = 0
p4_reply = p_ip4 / p_payload
p4_reply.ttl = 62 # check this
p4_reply.flags = 0
p4_reply.id = 512
self.pg_enable_capture()
self.pg0.add_stream(p4*1)
self.pg_start()
rx = self.pg1.get_capture(16)
reass_pkt = reassemble4(rx)
reass_pkt.show2()
p4_reply.show2()
self.validate(reass_pkt, p4_reply)
"""
# Reset MTU
self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, [current_mtu, 0, 0, 0])
def test_ip6_mtu(self):
"""IP6 MTU test"""
current_mtu = self.get_mtu(self.pg1.sw_if_index)
p_ether = Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
p_ip6 = IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6)
p_payload = UDP(sport=1234, dport=1234) / self.payload(current_mtu - 40 - 8)
p6 = p_ether / p_ip6 / p_payload
p6_reply = p_ip6 / p_payload
p6_reply.hlim -= 1
rx = self.send_and_expect(self.pg0, p6 * 9, self.pg1)
for p in rx:
self.validate(p[1], p6_reply)
# MTU (only checked on encap)
self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, [1280, 0, 0, 0])
self.assertEqual(1280, self.get_mtu(self.pg1.sw_if_index))
# Should fail. Too large MTU
p_icmp6 = ICMPv6PacketTooBig(mtu=1280, cksum=0x4C7A)
icmp6_reply = (
IPv6(src=self.pg0.local_ip6, dst=self.pg0.remote_ip6, hlim=255, plen=1240)
/ p_icmp6
/ p_ip6
/ p_payload
)
icmp6_reply[2].hlim -= 1
s = bytes(icmp6_reply)
icmp6_reply_str = s[0:1280]
rx = self.send_and_expect_some(self.pg0, p6 * 9, self.pg0)
for p in rx:
self.validate_bytes(bytes(p[1]), icmp6_reply_str)
self.assert_error_counter_equal("/err/ip6-input/mtu_exceeded", 9)
# Reset MTU
self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, [current_mtu, 0, 0, 0])
if __name__ == "__main__":
unittest.main(testRunner=VppTestRunner)
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