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.link_mtu
  80         return 0
  81
  82     def test_ip4_mtu(self):
  83         """ IP4 MTU test """
  84
  85         #
  86         # TODO: Link MTU is 216 bytes 'off'. Fix when L3 MTU patches committed
  87         #
  88         mtu_offset = 216
  89         p_ether = Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
  90         p_ip4 = IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4,
  91                    flags='DF')
  92
  93         # TODO: Re-enable when MTU fixes are committed
  94         current_mtu = self.get_mtu(self.pg1.sw_if_index)
  95         current_mtu -= mtu_offset
  96
  97         p_payload = UDP(sport=1234, dport=1234) / self.payload(
  98             current_mtu - 20 - 8)
  99
 100         p4 = p_ether / p_ip4 / p_payload
 101         p4_reply = p_ip4 / p_payload
 102         p4_reply.ttl -= 1
 103         rx = self.send_and_expect(self.pg0, p4*11, self.pg1)
 104         for p in rx:
 105             self.validate(p[1], p4_reply)
 106
 107         # MTU
 108         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, 576 + mtu_offset)
 109         self.assertEqual(576, self.get_mtu(self.pg1.sw_if_index) - mtu_offset)
 110
 111         # Should fail. Too large MTU
 112         p_icmp4 = ICMP(type='dest-unreach', code='fragmentation-needed',
 113                        nexthopmtu=576, chksum=0x2dbb)
 114         icmp4_reply = (IP(src=self.pg0.local_ip4,
 115                           dst=self.pg0.remote_ip4,
 116                           ttl=254, len=576, id=0) /
 117                        p_icmp4 / p_ip4 / p_payload)
 118         icmp4_reply[1].ttl -= 1
 119         n = icmp4_reply.__class__(str(icmp4_reply))
 120         s = str(icmp4_reply)
 121         icmp4_reply = s[0:576]
 122         rx = self.send_and_expect(self.pg0, p4*11, self.pg0)
 123         for p in rx:
 124             # p.show2()
 125             # n.show2()
 126             self.validate_bytes(str(p[1]), icmp4_reply)
 127
 128         '''
 129         # Now with DF off. Expect fragments.
 130         # First go with 1500 byte packets.
 131         p_payload = UDP(sport=1234, dport=1234) / self.payload(
 132             1500 - 20 - 8)
 133         p4 = p_ether / p_ip4 / p_payload
 134         p4.flags = 0
 135         p4_reply = p_ip4 / p_payload
 136         p4_reply.ttl = 62 # check this
 137         p4_reply.flags = 0
 138         p4_reply.id = 256
 139         self.pg_enable_capture()
 140         self.pg0.add_stream(p4*1)
 141         self.pg_start()
 142         rx = self.pg1.get_capture(3)
 143         print('RX', len(rx))
 144         reass_pkt = reassemble(rx)
 145         self.validate(reass_pkt, p4_reply)
 146         '''
 147         # Now what happens with a 9K frame
 148         '''
 149         p_payload = UDP(sport=1234, dport=1234) / self.payload(
 150             current_mtu - 20 - 8)
 151         p4 = p_ether / p_ip4 / p_payload
 152         p4.flags = 0
 153         p4_reply = p_ip4 / p_payload
 154         p4_reply.ttl = 62 # check this
 155         p4_reply.flags = 0
 156         p4_reply.id = 512
 157
 158         self.pg_enable_capture()
 159         self.pg0.add_stream(p4*1)
 160         self.pg_start()
 161         rx = self.pg1.get_capture(16)
 162         reass_pkt = reassemble(rx)
 163         reass_pkt.show2()
 164         p4_reply.show2()
 165         self.validate(reass_pkt, p4_reply)
 166         '''
 167         # Reset MTU
 168         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, current_mtu)
 169
 170     @unittest.skip("Enable when IPv6 fragmentation is added")
 171     def test_ip6_mtu(self):
 172         """ IP6 MTU test """
 173
 174         p_ether = Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac)
 175         p_ip6 = IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6)
 176
 177         current_mtu = self.get_mtu(self.pg1.sw_if_index)
 178         p_payload = UDP(sport=1234, dport=1234) / self.payload(
 179             current_mtu - 40 - 8)
 180
 181         p6 = p_ether / p_ip6 / p_payload
 182         p6_reply = p_ip6 / p_payload
 183         p6_reply.hlim -= 1
 184         rx = self.send_and_expect(self.pg0, p6*9, self.pg1)
 185         for p in rx:
 186             self.validate(p[1], p6_reply)
 187
 188         # MTU (only checked on encap)
 189         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, 1280)
 190         self.assertEqual(1280, self.get_mtu(self.pg1.sw_if_index))
 191
 192         # Should fail. Too large MTU
 193         p_icmp6 = ICMPv6PacketTooBig(mtu=1280, cksum=0x4c7a)
 194         icmp6_reply = (IPv6(src=self.pg0.local_ip6,
 195                             dst=self.pg0.remote_ip6,
 196                             hlim=254, plen=1240) /
 197                        p_icmp6 / p_ip6 / p_payload)
 198         icmp6_reply[2].hlim -= 1
 199         n = icmp6_reply.__class__(str(icmp6_reply))
 200         s = str(icmp6_reply)
 201         icmp6_reply = s[0:1280]
 202
 203         rx = self.send_and_expect(self.pg0, p6*9, self.pg0)
 204         for p in rx:
 205             self.validate_bytes(str(p[1]), icmp6_reply)
 206
 207         # Reset MTU
 208         self.vapi.sw_interface_set_mtu(self.pg1.sw_if_index, current_mtu)
 209
 210
 211 if __name__ == '__main__':
 212     unittest.main(testRunner=VppTestRunner)