text: #!/usr/bin/env python
  #
  #  Copyright (c) 2018, The OpenThread Authors.
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  #     derived from this software without specific prior written permission.
  #
  #  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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  #  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  #  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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  #  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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  #  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  #  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  #  POSSIBILITY OF SUCH DAMAGE.
  
  import time
  import wpan
  from wpan import verify
  
  #-----------------------------------------------------------------------------------------------------------------------
  # Test description: Adding/Removing IPv6 addresses on routers and SEDs on network interface.
  #
  # Test topology:
  #
  #     r1 ---- r2
  #     |       |
  #     |       |
  #    fed1    sed2
  #
  # IPv6 addresses are added as follows:
  # - On `r2`   add `IP6_ADDR_1` with prefix `IP6_PREFIX_1`
  # - On `fed1` add `IP6_ADDR_2` with prefix `IP6_PREFIX_2`
  # - On `sed2` add `IP6_ADDR_3` with prefix `IP6_PREFIX_3`
  #
  # The test then covers the following:
  # - Verify that the addresses are present in "IPv6:AllAddresses" wpantund property on the corresponding node.
  # - Verify that all prefixes are present in network data with correct configuration flags (on all nodes).
  # - Verify that `sed2`'s address is present in `r2` (its parent) "Thread:ChildTable:Addresses".
  # - Verify that addresses/prefixes are retained by wpantund over NCP reset.
  # - Verify that when an IPv6 address is removed from network interface, its corresponding prefix is also removed from
  #   all nodes.
  
  test_name = __file__[:-3] if __file__.endswith('.py') else __file__
  print '-' * 120
  print 'Starting \'{}\''.format(test_name)
  
  #-----------------------------------------------------------------------------------------------------------------------
  # Creating `wpan.Nodes` instances
  
  speedup = 4
  wpan.Node.set_time_speedup_factor(speedup)
  
  r1   = wpan.Node()
  fed1 = wpan.Node()
  r2   = wpan.Node()
  sed2 = wpan.Node()
  
  all_nodes = [r1, fed1, r2, sed2]
  
  #-----------------------------------------------------------------------------------------------------------------------
  # Init all nodes
  
  wpan.Node.init_all_nodes()
  
  #-----------------------------------------------------------------------------------------------------------------------
  # Build network topology
  #
  #   r1 ---- r2
  #   |       |
  #   |       |
  #  fed1    sed2
  
  
  r1.whitelist_node(r2)
  r2.whitelist_node(r1)
  
  r1.whitelist_node(fed1)
  fed1.whitelist_node(r1)
  
  r2.whitelist_node(sed2)
  sed2.whitelist_node(r2)
  
  r1.form("ip-addr")
  r2.join_node(r1, wpan.JOIN_TYPE_ROUTER)
  
  fed1.join_node(r1, wpan.JOIN_TYPE_END_DEVICE)
  sed2.join_node(r2, wpan.JOIN_TYPE_SLEEPY_END_DEVICE)
  
  sed2.set(wpan.WPAN_POLL_INTERVAL, '300')
  
  #-----------------------------------------------------------------------------------------------------------------------
  # Test implementation
  
  IP6_PREFIX_1 = "fd00:c0de::"
  IP6_PREFIX_2 = "fd00:deed::"
  IP6_PREFIX_3 = "fd00:beef::"
  
  IP6_ADDR_1  = IP6_PREFIX_1 + "1"
  IP6_ADDR_2  = IP6_PREFIX_2 + "2"
  IP6_ADDR_3  = IP6_PREFIX_3 + "3"
  
  # On `r2`   add `IP6_ADDR_1` with prefix `IP6_PREFIX_1`
  # On `fed1` add `IP6_ADDR_2` with prefix `IP6_PREFIX_2`
  # On `sed2` add `IP6_ADDR_3` with prefix `IP6_PREFIX_3`
  
  r2.add_ip6_address_on_interface(IP6_ADDR_1, prefix_len=64)
  fed1.add_ip6_address_on_interface(IP6_ADDR_2, prefix_len=64)
  sed2.add_ip6_address_on_interface(IP6_ADDR_3, prefix_len=64)
  
  def check_addresses_and_prefixes():
      # Verify that the addresses are present in "IPv6:AllAddresses" wpantund property on the corresponding node.
      verify(r2.find_ip6_address_with_prefix(IP6_PREFIX_1)   == IP6_ADDR_1)
      verify(fed1.find_ip6_address_with_prefix(IP6_PREFIX_2) == IP6_ADDR_2)
      verify(sed2.find_ip6_address_with_prefix(IP6_PREFIX_3) == IP6_ADDR_3)
  
      # Verify that all prefixes are present in network data on all nodes (with correct flags).
      for prefix in [IP6_PREFIX_1, IP6_PREFIX_2, IP6_PREFIX_3]:
          for node in all_nodes:
              prefixes = wpan.parse_on_mesh_prefix_result(node.get(wpan.WPAN_THREAD_ON_MESH_PREFIXES))
              for p in prefixes:
                  if p.prefix == prefix:
                      verify(p.prefix_len == '64')
                      verify(p.is_stable())
                      verify(p.is_on_mesh() == True)
                      verify(p.is_preferred() == True)
                      verify(p.is_def_route() == False)
                      verify(p.is_slaac() == False)
                      verify(p.is_dhcp() == False)
                      verify(p.is_config() == False)
                      verify(p.priority == "med")
                      break
              else: # `for` loop finished without finding the prefix.
                  raise wpan.VerifyError('Did not find prefix {} on node {}'.format(prefix, node))
  
      # Verify that IPv6 address of `sed2` is present on `r2` (its parent) "Thread:ChildTable:Addresses".
      addr_str = r2.get(wpan.WPAN_THREAD_CHILD_TABLE_ADDRESSES)
      # search for index on address in the `addr_str` and ensure it is non-negative.
      verify(addr_str.find(IP6_ADDR_3) >= 0)
  
  
  # Check the addresses and prefixes (wait time 20 seconds)
  wpan.verify_within(check_addresses_and_prefixes, 15)
  
  # Reset the nodes and verify that all addresses/prefixes are preserved.
  fed1.reset()
  sed2.reset()
  wpan.verify_within(check_addresses_and_prefixes, 20)
  
  # Remove address from `r2`
  r2.remove_ip6_address_on_interface(IP6_ADDR_1, prefix_len=64)
  
  def check_address_prefix_removed():
      # Verify that address is removed from r2
      verify(r2.find_ip6_address_with_prefix(IP6_PREFIX_1) == '')
      # Verify that the related prefix is also removed on all nodes
      for node in all_nodes:
          prefixes = wpan.parse_on_mesh_prefix_result(node.get(wpan.WPAN_THREAD_ON_MESH_PREFIXES))
          for p in prefixes:
              verify(p.prefix != IP6_PREFIX_1)
  
  # Check the addresses and prefixes (wait time 15 seconds)
  wpan.verify_within(check_address_prefix_removed, 15)
  
  #-----------------------------------------------------------------------------------------------------------------------
  # Test finished
  
  wpan.Node.finalize_all_nodes()
  
  print '\'{}\' passed.'.format(test_name)
  