test/test_mtu.py

   1 #!/usr/bin/env python
   2 """IP4 and IP6 MTU functional tests"""
   3
   4 #
   5 # Add tests for:
   6 # - sub interfaces
   7 # - Verify that adjacencies inherit MTU correctly
   8 # - Verify that sub-interfaces inherit MTU correctly
   9 # - Different types of interfaces?
  10 #
  11 import unittest
  12 from scapy.layers.inet6 import IPv6, Ether, IP, UDP, ICMPv6PacketTooBig
  13 from scapy.layers.inet import ICMP
  14 from framework import VppTestCase, VppTestRunner
  15 from vpp_ip_route import VppIpRoute, VppRoutePath, DpoProto
  16 from socket import AF_INET, AF_INET6, inet_pton
  17 import StringIO
  18
  19 """ Test_mtu is a subclass of VPPTestCase classes.
  20     MTU tests.
  21 """
  22
  23
  24 def reassemble(listoffragments):
  25     buffer = StringIO.StringIO()
  26     first = listoffragments[0]
  27     buffer.seek(20)
  28     for pkt in listoffragments:
  29         # pkt.show2()
  30         buffer.seek(pkt[IP].frag*8)
  31         buffer.write(pkt[IP].payload)
  32     first.len = len(buffer.getvalue()) + 20
  33     first.flags = 0
  34     del(first.chksum)
  35     header = str(first[IP])[:20]
  36     return first[IP].__class__(header + buffer.getvalue())
  37
  38
  39 class TestMTU(VppTestCase):
  40     """ MTU Test Case """
  41
  42     @classmethod
  43     def setUpClass(cls):
  44         super(TestMTU, cls).setUpClass()
  45         cls.create_pg_interfaces(range(2))
  46         cls.interfaces = list(cls.pg_interfaces)
  47
  48     def setUp(cls):
  49         super(TestMTU, cls).setUp()
  50         for i in cls.interfaces:
  51             i.admin_up()
  52             i.config_ip4()
  53             i.config_ip6()
  54             i.disable_ipv6_ra()
  55             i.resolve_arp()
  56             i.resolve_ndp()
  57
  58     def tearDown(self):
  59         super(TestMTU, self).tearDown()
  60         if not self.vpp_dead:
  61             for i in self.pg_interfaces:
  62                 i.unconfig_ip4()
  63                 i.unconfig_ip6()
  64                 i.admin_down()
  65
  66     def validate(self, rx, expected):
  67         self.assertEqual(rx, expected.__class__(str(expected)))
  68
  69     def validate_bytes(self, rx, expected):
  70         self.assertEqual(rx, expected)
  71
  72     def payload(self, len):
  73         return 'x' * len
  74
  75     def get_mtu(self, sw_if_index):
  76         rv = self.vapi.sw_interface_dump()
  77         for i in rv:
  78             if i.sw_if_index == sw_if_index:
  79                 return i.mtu[0]
  80         return 0
  81
  82     def test_ip4_mtu(self):
  83         """ IP4 MTU test """
  84
  85         p_ether = Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
  86         p_ip4 = IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4,
  87                    flags='DF')
  88
  89         current_mtu = self.get_mtu(self.pg1.sw_if_index)
  90
  91         p_payload = UDP(sport=1234, dport=1234) / self.payload(
  92             current_mtu - 20 - 8)
  93
  94         p4 = p_ether / p_ip4 / p_payload
  95         p4_reply = p_ip4 / p_payload
  96         p4_reply.ttl -= 1
  97         rx = self.send_and_expect(self.pg0, p4*11, self.pg1)
  98         for p in rx:
  99             self.validate(p[1], p4_reply)
 100
 101         # MTU
 102         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, [576, 0, 0, 0])
 103         self.assertEqual(576, self.get_mtu(self.pg1.sw_if_index))
 104
 105         # Should fail. Too large MTU
 106         p_icmp4 = ICMP(type='dest-unreach', code='fragmentation-needed',
 107                        nexthopmtu=576, chksum=0x2dbb)
 108         icmp4_reply = (IP(src=self.pg0.local_ip4,
 109                           dst=self.pg0.remote_ip4,
 110                           ttl=254, len=576, id=0) /
 111                        p_icmp4 / p_ip4 / p_payload)
 112         icmp4_reply[1].ttl -= 1
 113         n = icmp4_reply.__class__(str(icmp4_reply))
 114         s = str(icmp4_reply)
 115         icmp4_reply = s[0:576]
 116         rx = self.send_and_expect(self.pg0, p4*11, self.pg0)
 117         for p in rx:
 118             # p.show2()
 119             # n.show2()
 120             self.validate_bytes(str(p[1]), icmp4_reply)
 121
 122         # Now with DF off. Expect fragments.
 123         # First go with 1500 byte packets.
 124         p_payload = UDP(sport=1234, dport=1234) / self.payload(
 125             1500 - 20 - 8)
 126         p4 = p_ether / p_ip4 / p_payload
 127         p4.flags = 0
 128         p4_reply = p_ip4 / p_payload
 129         p4_reply.ttl = 62  # check this
 130         p4_reply.flags = 0
 131         p4_reply.id = 256
 132         self.pg_enable_capture()
 133         self.pg0.add_stream(p4*1)
 134         self.pg_start()
 135         rx = self.pg1.get_capture(3)
 136         reass_pkt = reassemble(rx)
 137         self.validate(reass_pkt, p4_reply)
 138
 139         '''
 140         # Now what happens with a 9K frame
 141         p_payload = UDP(sport=1234, dport=1234) / self.payload(
 142             current_mtu - 20 - 8)
 143         p4 = p_ether / p_ip4 / p_payload
 144         p4.flags = 0
 145         p4_reply = p_ip4 / p_payload
 146         p4_reply.ttl = 62 # check this
 147         p4_reply.flags = 0
 148         p4_reply.id = 512
 149
 150         self.pg_enable_capture()
 151         self.pg0.add_stream(p4*1)
 152         self.pg_start()
 153         rx = self.pg1.get_capture(16)
 154         reass_pkt = reassemble(rx)
 155         reass_pkt.show2()
 156         p4_reply.show2()
 157         self.validate(reass_pkt, p4_reply)
 158         '''
 159
 160         # Reset MTU
 161         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index,
 162                                        [current_mtu, 0, 0, 0])
 163
 164     def test_ip6_mtu(self):
 165         """ IP6 MTU test """
 166
 167         current_mtu = self.get_mtu(self.pg1.sw_if_index)
 168
 169         p_ether = Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
 170         p_ip6 = IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6)
 171
 172         p_payload = UDP(sport=1234, dport=1234) / self.payload(
 173             current_mtu - 40 - 8)
 174
 175         p6 = p_ether / p_ip6 / p_payload
 176         p6_reply = p_ip6 / p_payload
 177         p6_reply.hlim -= 1
 178         rx = self.send_and_expect(self.pg0, p6*9, self.pg1)
 179         for p in rx:
 180             self.validate(p[1], p6_reply)
 181
 182         # MTU (only checked on encap)
 183         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, [1280, 0, 0, 0])
 184         self.assertEqual(1280, self.get_mtu(self.pg1.sw_if_index))
 185
 186         # Should fail. Too large MTU
 187         p_icmp6 = ICMPv6PacketTooBig(mtu=1280, cksum=0x4c7a)
 188         icmp6_reply = (IPv6(src=self.pg0.local_ip6,
 189                             dst=self.pg0.remote_ip6,
 190                             hlim=254, plen=1240) /
 191                        p_icmp6 / p_ip6 / p_payload)
 192         icmp6_reply[2].hlim -= 1
 193         n = icmp6_reply.__class__(str(icmp6_reply))
 194         s = str(icmp6_reply)
 195         icmp6_reply = s[0:1280]
 196
 197         rx = self.send_and_expect(self.pg0, p6*9, self.pg0)
 198         for p in rx:
 199             self.validate_bytes(str(p[1]), icmp6_reply)
 200
 201         # Reset MTU
 202         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index,
 203                                        [current_mtu, 0, 0, 0])
 204
 205
 206 if __name__ == '__main__':
 207     unittest.main(testRunner=VppTestRunner)