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 import DpoProto
  16 from vpp_ip_route import VppIpRoute, VppRoutePath
  17 from socket import AF_INET, AF_INET6, inet_pton
  18 import StringIO
  19
  20 """ Test_mtu is a subclass of VPPTestCase classes.
  21     MTU tests.
  22 """
  23
  24
  25 def reassemble(listoffragments):
  26     buffer = StringIO.StringIO()
  27     first = listoffragments[0]
  28     buffer.seek(20)
  29     for pkt in listoffragments:
  30         # pkt.show2()
  31         buffer.seek(pkt[IP].frag*8)
  32         buffer.write(pkt[IP].payload)
  33     first.len = len(buffer.getvalue()) + 20
  34     first.flags = 0
  35     del(first.chksum)
  36     header = str(first[IP])[:20]
  37     return first[IP].__class__(header + buffer.getvalue())
  38
  39
  40 class TestMTU(VppTestCase):
  41     """ MTU Test Case """
  42
  43     @classmethod
  44     def setUpClass(cls):
  45         super(TestMTU, cls).setUpClass()
  46         cls.create_pg_interfaces(range(2))
  47         cls.interfaces = list(cls.pg_interfaces)
  48
  49     def setUp(self):
  50         super(TestMTU, self).setUp()
  51         for i in self.interfaces:
  52             i.admin_up()
  53             i.config_ip4()
  54             i.config_ip6()
  55             i.disable_ipv6_ra()
  56             i.resolve_arp()
  57             i.resolve_ndp()
  58
  59     def tearDown(self):
  60         super(TestMTU, self).tearDown()
  61         if not self.vpp_dead:
  62             for i in self.pg_interfaces:
  63                 i.unconfig_ip4()
  64                 i.unconfig_ip6()
  65                 i.admin_down()
  66
  67     def validate(self, rx, expected):
  68         self.assertEqual(rx, expected.__class__(str(expected)))
  69
  70     def validate_bytes(self, rx, expected):
  71         self.assertEqual(rx, expected)
  72
  73     def payload(self, len):
  74         return 'x' * len
  75
  76     def get_mtu(self, sw_if_index):
  77         rv = self.vapi.sw_interface_dump()
  78         for i in rv:
  79             if i.sw_if_index == sw_if_index:
  80                 return i.mtu[0]
  81         return 0
  82
  83     def test_ip4_mtu(self):
  84         """ IP4 MTU test """
  85
  86         p_ether = Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
  87         p_ip4 = IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4,
  88                    flags='DF')
  89
  90         current_mtu = self.get_mtu(self.pg1.sw_if_index)
  91
  92         p_payload = UDP(sport=1234, dport=1234) / self.payload(
  93             current_mtu - 20 - 8)
  94
  95         p4 = p_ether / p_ip4 / p_payload
  96         p4_reply = p_ip4 / p_payload
  97         p4_reply.ttl -= 1
  98         rx = self.send_and_expect(self.pg0, p4*11, self.pg1)
  99         for p in rx:
 100             self.validate(p[1], p4_reply)
 101
 102         # MTU
 103         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, [576, 0, 0, 0])
 104         self.assertEqual(576, self.get_mtu(self.pg1.sw_if_index))
 105
 106         # Should fail. Too large MTU
 107         p_icmp4 = ICMP(type='dest-unreach', code='fragmentation-needed',
 108                        nexthopmtu=576, chksum=0x2dbb)
 109         icmp4_reply = (IP(src=self.pg0.local_ip4,
 110                           dst=self.pg0.remote_ip4,
 111                           ttl=254, len=576, id=0) /
 112                        p_icmp4 / p_ip4 / p_payload)
 113         icmp4_reply[1].ttl -= 1
 114         n = icmp4_reply.__class__(str(icmp4_reply))
 115         s = str(icmp4_reply)
 116         icmp4_reply = s[0:576]
 117         rx = self.send_and_expect(self.pg0, p4*11, self.pg0)
 118         for p in rx:
 119             # p.show2()
 120             # n.show2()
 121             self.validate_bytes(str(p[1]), icmp4_reply)
 122
 123         # Now with DF off. Expect fragments.
 124         # First go with 1500 byte packets.
 125         p_payload = UDP(sport=1234, dport=1234) / self.payload(
 126             1500 - 20 - 8)
 127         p4 = p_ether / p_ip4 / p_payload
 128         p4.flags = 0
 129         p4_reply = p_ip4 / p_payload
 130         p4_reply.ttl = 62  # check this
 131         p4_reply.flags = 0
 132         p4_reply.id = 256
 133         self.pg_enable_capture()
 134         self.pg0.add_stream(p4*1)
 135         self.pg_start()
 136         rx = self.pg1.get_capture(3)
 137         reass_pkt = reassemble(rx)
 138         self.validate(reass_pkt, p4_reply)
 139
 140         '''
 141         # Now what happens with a 9K frame
 142         p_payload = UDP(sport=1234, dport=1234) / self.payload(
 143             current_mtu - 20 - 8)
 144         p4 = p_ether / p_ip4 / p_payload
 145         p4.flags = 0
 146         p4_reply = p_ip4 / p_payload
 147         p4_reply.ttl = 62 # check this
 148         p4_reply.flags = 0
 149         p4_reply.id = 512
 150
 151         self.pg_enable_capture()
 152         self.pg0.add_stream(p4*1)
 153         self.pg_start()
 154         rx = self.pg1.get_capture(16)
 155         reass_pkt = reassemble(rx)
 156         reass_pkt.show2()
 157         p4_reply.show2()
 158         self.validate(reass_pkt, p4_reply)
 159         '''
 160
 161         # Reset MTU
 162         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index,
 163                                        [current_mtu, 0, 0, 0])
 164
 165     def test_ip6_mtu(self):
 166         """ IP6 MTU test """
 167
 168         current_mtu = self.get_mtu(self.pg1.sw_if_index)
 169
 170         p_ether = Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
 171         p_ip6 = IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6)
 172
 173         p_payload = UDP(sport=1234, dport=1234) / self.payload(
 174             current_mtu - 40 - 8)
 175
 176         p6 = p_ether / p_ip6 / p_payload
 177         p6_reply = p_ip6 / p_payload
 178         p6_reply.hlim -= 1
 179         rx = self.send_and_expect(self.pg0, p6*9, self.pg1)
 180         for p in rx:
 181             self.validate(p[1], p6_reply)
 182
 183         # MTU (only checked on encap)
 184         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, [1280, 0, 0, 0])
 185         self.assertEqual(1280, self.get_mtu(self.pg1.sw_if_index))
 186
 187         # Should fail. Too large MTU
 188         p_icmp6 = ICMPv6PacketTooBig(mtu=1280, cksum=0x4c7a)
 189         icmp6_reply = (IPv6(src=self.pg0.local_ip6,
 190                             dst=self.pg0.remote_ip6,
 191                             hlim=255, plen=1240) /
 192                        p_icmp6 / p_ip6 / p_payload)
 193         icmp6_reply[2].hlim -= 1
 194         n = icmp6_reply.__class__(str(icmp6_reply))
 195         s = str(icmp6_reply)
 196         icmp6_reply_str = s[0:1280]
 197
 198         rx = self.send_and_expect(self.pg0, p6*9, self.pg0)
 199         for p in rx:
 200             self.validate_bytes(str(p[1]), icmp6_reply_str)
 201
 202         # Reset MTU
 203         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index,
 204                                        [current_mtu, 0, 0, 0])
 205
 206
 207 if __name__ == '__main__':
 208     unittest.main(testRunner=VppTestRunner)