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#!/usr/bin/env python
"""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, VppTestRunner
from vpp_ip_route import VppIpRoute, VppRoutePath, DpoProto
from socket import AF_INET, AF_INET6, inet_pton
import StringIO
""" Test_mtu is a subclass of VPPTestCase classes.
MTU tests.
"""
def reassemble(listoffragments):
buffer = StringIO.StringIO()
first = listoffragments[0]
buffer.seek(20)
for pkt in listoffragments:
# pkt.show2()
buffer.seek(pkt[IP].frag*8)
buffer.write(pkt[IP].payload)
first.len = len(buffer.getvalue()) + 20
first.flags = 0
del(first.chksum)
header = str(first[IP])[:20]
return first[IP].__class__(header + buffer.getvalue())
class TestMTU(VppTestCase):
""" MTU Test Case """
@classmethod
def setUpClass(cls):
super(TestMTU, cls).setUpClass()
cls.create_pg_interfaces(range(2))
cls.interfaces = list(cls.pg_interfaces)
def setUp(cls):
super(TestMTU, cls).setUp()
for i in cls.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.assertEqual(rx, expected.__class__(str(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()
for i in rv:
if i.sw_if_index == sw_if_index:
return i.link_mtu
return 0
def test_ip4_mtu(self):
""" IP4 MTU test """
#
# TODO: Link MTU is 216 bytes 'off'. Fix when L3 MTU patches committed
#
mtu_offset = 216
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')
# TODO: Re-enable when MTU fixes are committed
current_mtu = self.get_mtu(self.pg1.sw_if_index)
current_mtu -= mtu_offset
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 + mtu_offset)
self.assertEqual(576, self.get_mtu(self.pg1.sw_if_index) - mtu_offset)
# 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=254, len=576, id=0) /
p_icmp4 / p_ip4 / p_payload)
icmp4_reply[1].ttl -= 1
n = icmp4_reply.__class__(str(icmp4_reply))
s = str(icmp4_reply)
icmp4_reply = s[0:576]
rx = self.send_and_expect(self.pg0, p4*11, self.pg0)
for p in rx:
# p.show2()
# n.show2()
self.validate_bytes(str(p[1]), icmp4_reply)
'''
# 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 = 62 # check this
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)
print('RX', len(rx))
reass_pkt = reassemble(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 = reassemble(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)
@unittest.skip("Enable when IPv6 fragmentation is added")
def test_ip6_mtu(self):
""" IP6 MTU test """
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)
current_mtu = self.get_mtu(self.pg1.sw_if_index)
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)
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=254, plen=1240) /
p_icmp6 / p_ip6 / p_payload)
icmp6_reply[2].hlim -= 1
n = icmp6_reply.__class__(str(icmp6_reply))
s = str(icmp6_reply)
icmp6_reply = s[0:1280]
rx = self.send_and_expect(self.pg0, p6*9, self.pg0)
for p in rx:
self.validate_bytes(str(p[1]), icmp6_reply)
# Reset MTU
self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, current_mtu)
if __name__ == '__main__':
unittest.main(testRunner=VppTestRunner)
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