def add_relay(self, p, srv_ip, relay_ip=None):
"""Modify passed DHCP client packet as if a DHCP relay would
Encapsulate DHCPv6 request message into DHCPv6 RelayForward, update UDP
src port and set IP dest address.
Args:
p (scapy.packet.Packet): DHCP client packet
srv_ip (str): IPv6 address of server to relay to
relay_ip (str, optional): Defaults to dhcpdoctor's IPv6. IPv6 address
of relay.
"""
if not relay_ip:
relay_ip = get_if_addr6(conf.iface)
# get payload of UDP to get whatever type of DHCPv6 request it is and
# replace it with our relay data
dhcp_request = p[UDP].payload
assert isinstance(dhcp_request, DHCP6)
p[UDP].remove_payload()
p[UDP].add_payload(
DHCP6_RelayForward(linkaddr=relay_ip, peeraddr=p[IPv6].src) /
DHCP6OptRelayMsg(message=dhcp_request))
p[UDP].sport = 547
p[IPv6].src = relay_ip
p[IPv6].dst = srv_ip
if settings.DEBUG:
print(p.show())
def test_dhcpv6_relay_forward_hop_limit_exceeded(self):
test_trid = 0xc0ffee
hoplimit = self.CONFIG_DHCPV6_RELAY_HOP_LIMIT
pkt = DHCP6_RelayForward(hopcount=hoplimit + 1,
peeraddr="fe80::f00:1337") / \
DHCP6OptIfaceId(ifaceid=b"ab") / \
DHCP6OptRelayMsg(message=DHCP6_Rebind(trid=test_trid))
self.assert_pkt_ignored(pkt, client_pkt=False)
def test_dhcpv6_relay_forward_from_unspec(self):
hopcount = self.CONFIG_DHCPV6_RELAY_HOP_LIMIT - 1
peeraddr = "fe80::f00:1337"
ifaceid = b"ab"
self.assertGreater(hopcount, 0)
pkt = DHCP6_RelayForward(peeraddr=peeraddr, hopcount=hopcount) / \
DHCP6OptIfaceId(ifaceid=ifaceid) / \
DHCP6OptRelayMsg(message=DHCP6_Rebind(trid=self.test_trid))
self.assert_pkt_ignored(pkt, ipv6_src="::")
def test_dhcpv6_simple_relay_reply_foreign_option(self):
pkt = DHCP6_RelayReply(peeraddr=self.tap_lladdr) / \
DHCP6OptIfaceId(ifaceid=self.node_ifaceid) / \
DHCP6OptClientId() / \
DHCP6OptRelayMsg(message=DHCP6_Reply(trid=self.test_trid))
result = self.send_and_exp_pkts(pkt, DHCP6_Reply, client=False)
self.assert_len(result, 1)
pkt = result[0]
self.assert_relayed_reply_pkt_w_trid(pkt, DHCP6_Reply)
self.assert_node_responsive()
def test_dhcpv6_relay_forward_options_reversed(self):
hopcount = self.CONFIG_DHCPV6_RELAY_HOP_LIMIT - 1
peeraddr = "fe80::f00:1337"
ifaceid = b"ab"
self.assertGreater(hopcount, 0)
pkt = DHCP6_RelayForward(peeraddr=peeraddr, hopcount=hopcount) / \
DHCP6OptRelayMsg(message=DHCP6_Rebind(trid=self.test_trid)) / \
DHCP6OptIfaceId(ifaceid=ifaceid)
rpkt = self._test_dhcpv6_relay_forward(pkt, hopcount, peeraddr,
ifaceid)
self.assertIn(DHCP6_Rebind, rpkt[DHCP6OptRelayMsg].message)
self.assertEqual(rpkt[DHCP6OptRelayMsg].message[DHCP6_Rebind].trid,
self.test_trid)
def test_dhcpv6_nested_relay_reply(self):
peeraddr = "fe80::f00:affe"
ifaceid = b"abcd"
pkt = DHCP6_RelayReply(peeraddr=self.tap_lladdr) / \
DHCP6OptIfaceId(ifaceid=self.node_ifaceid) / \
DHCP6OptRelayMsg(
message=DHCP6_RelayReply(peeraddr=peeraddr) /
# noqa: E131 (easier to read with this indentation)
DHCP6OptIfaceId(ifaceid=ifaceid) /
DHCP6OptRelayMsg(
message=DHCP6_Reconf(trid=self.test_trid)
)
)
result = self.send_and_exp_pkts(pkt, DHCP6_Reconf, client=False)
self.assert_len(result, 1)
pkt = result[0]
self.assertIn(DHCP6_RelayReply, pkt)
self.assertNotIn(DHCP6_RelayReply, pkt[DHCP6_RelayReply].message)
self.assertEqual(pkt[DHCP6_RelayReply].peeraddr, peeraddr)
self.assertIn(DHCP6OptIfaceId, pkt)
self.assertEqual(pkt[DHCP6OptIfaceId].ifaceid, ifaceid)
self.assertIn(DHCP6_Reconf, pkt[DHCP6_RelayReply].message)
self.assertEqual(pkt[DHCP6_Reconf].trid, self.test_trid)
self.assert_node_responsive()
def test_dhcpv6_relay_reply_empty(self):
pkt = DHCP6_RelayReply(peeraddr=self.tap_lladdr) / \
DHCP6OptIfaceId(ifaceid=self.node_ifaceid) / \
DHCP6OptRelayMsg()
self.assert_pkt_ignored(pkt, client_pkt=False)
def test_dhcpv6_relay_reply_no_ifaceid_no_linkaddr(self):
pkt = DHCP6_RelayReply(peeraddr=self.tap_lladdr) / \
DHCP6OptRelayMsg(message=DHCP6_Reply(trid=self.test_trid))
self.assert_pkt_ignored(pkt, client_pkt=False)
def test_dhcpv6_relay_reply_invalid_optlen(self):
pkt = DHCP6_RelayReply(peeraddr=self.tap_lladdr) / \
DHCP6OptIfaceId(ifaceid=self.node_ifaceid) / \
DHCP6OptRelayMsg(optlen=32,
message=DHCP6_Reply(trid=self.test_trid))
self.assert_pkt_ignored(pkt, client_pkt=False)
def test_dhcpv6_relay_reply_unexpected_peeraddr(self):
pkt = DHCP6_RelayReply(peeraddr="fe80::abcd:f00:1337") / \
DHCP6OptIfaceId(ifaceid=self.node_ifaceid) / \
DHCP6OptRelayMsg(message=DHCP6_Reply(trid=self.test_trid))
self.assert_pkt_ignored(pkt, client_pkt=False)
def test_dhcpv6_relay_reply_unexpected_ifaceid(self):
pkt = DHCP6_RelayReply(peeraddr=self.tap_lladdr) / \
DHCP6OptIfaceId(ifaceid=b"ab") / \
DHCP6OptRelayMsg(message=DHCP6_Reply(trid=self.test_trid))
self.assert_pkt_ignored(pkt, client_pkt=False)
def test_dhcpv6_simple_relay_reply_foreign_option_w_bogus_optlen(self):
pkt = DHCP6_RelayReply(peeraddr=self.tap_lladdr) / \
DHCP6OptIfaceId(ifaceid=self.node_ifaceid) / \
DHCP6OptRelayMsg(message=DHCP6_Reply(trid=self.test_trid)) / \
DHCP6OptClientId(optlen=32)
self.assert_pkt_ignored(pkt, client_pkt=False)
def test_dhcpv6_simple_relay_reply_options_reversed(self):
pkt = DHCP6_RelayReply(peeraddr=self.tap_lladdr) / \
DHCP6OptRelayMsg(message=DHCP6_Reply(trid=self.test_trid)) / \
DHCP6OptIfaceId(ifaceid=self.node_ifaceid)
self._test_dhcpv6_simple_relay_reply(pkt, DHCP6_Reply)
def test_dhcpv6_simple_relay_reply(self):
pkt = DHCP6_RelayReply(peeraddr=self.tap_lladdr) / \
DHCP6OptIfaceId(ifaceid=self.node_ifaceid) / \
DHCP6OptRelayMsg(message=DHCP6_Advertise(trid=self.test_trid))
self._test_dhcpv6_simple_relay_reply(pkt, DHCP6_Advertise)