1 files changed, 132 insertions, 0 deletions
diff --git a/resources/traffic_scripts/dhcp/check_dhcp_request_ack.py b/resources/traffic_scripts/dhcp/check_dhcp_request_ack.py
new file mode 100755
index 0000000000..8a3839cda7
--- /dev/null
+++ b/resources/traffic_scripts/dhcp/check_dhcp_request_ack.py
@@ -0,0 +1,132 @@
+#!/usr/bin/env python
+# Copyright (c) 2016 Cisco and/or its affiliates.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at:
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Traffic script that sends a DHCP ACK message when DHCP REQUEST message is
+received."""
+
+import sys
+
+from scapy.layers.l2 import Ether
+from scapy.layers.inet import IP, UDP
+from scapy.layers.dhcp import BOOTP, DHCP
+
+from resources.libraries.python.PacketVerifier import RxQueue, TxQueue
+from resources.libraries.python.TrafficScriptArg import TrafficScriptArg
+
+
+def is_discover(pkt):
+    """If DHCP message type option is set to dhcp discover return True,
+    else return False. False is returned also if exception occurs."""
+    dhcp_discover = 1
+    try:
+        dhcp_options = pkt['BOOTP']['DHCP options'].options
+        message_type = filter(lambda x: x[0] == 'message-type',
+                              dhcp_options)
+        message_type = message_type[0][1]
+        return message_type == dhcp_discover
+    except:
+        return False
+
+
+def is_request(pkt):
+    """If DHCP message type option is DHCP REQUEST return True,
+    else return False. False is returned also if exception occurs."""
+    dhcp_request = 3
+    try:
+        dhcp_options = pkt['BOOTP']['DHCP options'].options
+        message_type = filter(lambda x: x[0] == 'message-type',
+                              dhcp_options)
+        message_type = message_type[0][1]
+        return message_type == dhcp_request
+    except:
+        return False
+
+
+def main():
+    """Main function of the script file."""
+    args = TrafficScriptArg(['server_mac', 'server_ip', 'client_ip',
+                             'client_mask', 'lease_time'])
+
+    server_if = args.get_arg('rx_if')
+    server_mac = args.get_arg('server_mac')
+    server_ip = args.get_arg('server_ip')
+
+    client_ip = args.get_arg('client_ip')
+    client_mask = args.get_arg('client_mask')
+
+    lease_time = int(args.get_arg('lease_time'))
+
+    rxq = RxQueue(server_if)
+    txq = TxQueue(server_if)
+    sent_packets = []
+
+    for _ in range(10):
+        dhcp_discover = rxq.recv(10)
+        if is_discover(dhcp_discover):
+            break
+    else:
+        raise RuntimeError("DHCP DISCOVER Rx error.")
+
+    dhcp_offer = Ether(src=server_mac, dst=dhcp_discover.src)
+    dhcp_offer /= IP(src=server_ip, dst="255.255.255.255")
+    dhcp_offer /= UDP(sport=67, dport=68)
+    dhcp_offer /= BOOTP(op=2,
+                        xid=dhcp_discover['BOOTP'].xid,
+                        yiaddr=client_ip,
+                        siaddr=server_ip,
+                        chaddr=dhcp_discover['BOOTP'].chaddr)
+    dhcp_offer_options = [("message-type", "offer"),  # Option 53
+                          ("subnet_mask", client_mask),  # Option 1
+                          ("server_id", server_ip),  # Option 54, dhcp server
+                          ("lease_time", lease_time),  # Option 51
+                          "end"]
+    dhcp_offer /= DHCP(options=dhcp_offer_options)
+
+    txq.send(dhcp_offer)
+    sent_packets.append(dhcp_offer)
+
+    max_other_pkts = 10
+    for _ in range(0, max_other_pkts):
+        dhcp_request = rxq.recv(5, sent_packets)
+        if not dhcp_request:
+            raise RuntimeError("DHCP REQUEST Rx timeout.")
+        if is_request(dhcp_request):
+            break
+    else:
+        raise RuntimeError("Max RX packet limit reached.")
+
+    # Send dhcp ack
+    dhcp_ack = Ether(src=server_mac, dst=dhcp_request.src)
+    dhcp_ack /= IP(src=server_ip, dst="255.255.255.255")
+    dhcp_ack /= UDP(sport=67, dport=68)
+    dhcp_ack /= BOOTP(op=2,
+                      xid=dhcp_request['BOOTP'].xid,
+                      yiaddr=client_ip,
+                      siaddr=server_ip,
+                      flags=dhcp_request['BOOTP'].flags,
+                      chaddr=dhcp_request['BOOTP'].chaddr)
+    dhcp_ack_options = [("message-type", "ack"),  # Option 53. 5: ACK, 6: NAK
+                        ("subnet_mask", client_mask),  # Option 1
+                        ("server_id", server_ip),  # Option 54, dhcp server
+                        ("lease_time", lease_time),  # Option 51,
+                        "end"]
+    dhcp_ack /= DHCP(options=dhcp_ack_options)
+
+    txq.send(dhcp_ack)
+    sent_packets.append(dhcp_ack)
+
+    sys.exit(0)
+
+if __name__ == "__main__":
+    main()