def testSendToOnlinkDestination(self):
# [3] Get an IPv6 address back, in optimistic DAD start-up.
self.SetDAD(self.test_ifname, 1) # Enable DAD
self.SetOptimisticDAD(self.test_ifname, 1)
self.SetUseOptimistic(self.test_ifname, 1)
# Send a RA to start SLAAC and subsequent DAD.
self.SendRA(self.test_netid, 0)
# Prove optimism and usability.
self.assertAddressHasExpectedAttributes(self.test_ip,
self.test_ifindex,
iproute.IFA_F_OPTIMISTIC)
self.assertAddressUsable(self.test_ip, self.test_netid)
self.assertAddressSelected(self.test_ip, self.test_netid)
# [4] Send to an on-link destination and observe a Neighbor Solicitation
# packet with a source address that is NOT the optimistic address.
# In this setup, the only usable address is the link-local address.
onlink_dest = self.GetRandomDestination(
self.IPv6Prefix(self.test_netid))
self.SendWithSourceAddress(self.test_ip, self.test_netid, onlink_dest)
if net_test.LinuxVersion() >= (3, 18, 0):
# Older versions will actually choose the optimistic address to
# originate Neighbor Solications (RFC violation).
expected_ns = packets.NS(self.test_lladdr, onlink_dest,
self.MyMacAddress(self.test_netid))[1]
self.ExpectPacketOn(self.test_netid, "link-local NS", expected_ns)
def testOnlinkCommunication(self):
"""Checks that on-link communication goes direct and not through routers."""
for netid in self.tuns:
# Send a UDP packet to a random on-link destination.
s = net_test.UDPSocket(AF_INET6)
iface = self.GetInterfaceName(netid)
self.BindToDevice(s, iface)
# dstaddr can never be our address because GetRandomDestination only fills
# in the lower 32 bits, but our address has 0xff in the byte before that
# (since it's constructed from the EUI-64 and so has ff:fe in the middle).
dstaddr = self.GetRandomDestination(self.IPv6Prefix(netid))
s.sendto(UDP_PAYLOAD, (dstaddr, 53))
# Expect an NS for that destination on the interface.
myaddr = self.MyAddress(6, netid)
mymac = self.MyMacAddress(netid)
desc, expected = packets.NS(myaddr, dstaddr, mymac)
msg = "Sending UDP packet to on-link destination: expecting %s" % desc
time.sleep(
0.0001) # Required to make the test work on kernel 3.1(!)
self.ExpectPacketOn(netid, msg, expected)
# Send an NA.
tgtmac = "02:00:00:00:%02x:99" % netid
_, reply = packets.NA(dstaddr, myaddr, tgtmac)
# Don't use ReceivePacketOn, since that uses the router's MAC address as
# the source. Instead, construct our own Ethernet header with source
# MAC of tgtmac.
reply = scapy.Ether(src=tgtmac, dst=mymac) / reply
self.ReceiveEtherPacketOn(netid, reply)
# Expect the kernel to send the original UDP packet now that the ND cache
# entry has been populated.
sport = s.getsockname()[1]
desc, expected = packets.UDP(6, myaddr, dstaddr, sport=sport)
msg = "After NA response, expecting %s" % desc
self.ExpectPacketOn(netid, msg, expected)