[arp_responder]: Add IPv6 support

tests/scripts/arp_responder.py

@@ -15,6 +15,8 @@
 scapy2.conf.use_pcap=True
 import scapy.arch.pcapdnet
 
+NEIGH_SOLICIT_ICMP_MSG_TYPE = 135
+
 def hexdump(data):
     print " ".join("%02x" % ord(d) for d in data)
 
@@ -46,7 +48,7 @@ def __del__(self):
             self.socket.close()
 
     def bind(self):
-        self.socket = scapy2.conf.L2listen(iface=self.iface, filter='arp')
+        self.socket = scapy2.conf.L2listen(iface=self.iface, filter='arp || ip6[40] = {}'.format(NEIGH_SOLICIT_ICMP_MSG_TYPE))
 
     def handler(self):
         return self.socket
@@ -85,6 +87,7 @@ def poll(self):
 
 class ARPResponder(object):
     ARP_PKT_LEN = 64
+    NDP_PKT_LEN = 90
     ARP_OP_REQUEST = 1
     def __init__(self, ip_sets):
         self.arp_chunk = binascii.unhexlify('08060001080006040002') # defines a part of the packet for ARP Reply
@@ -97,9 +100,12 @@ def __init__(self, ip_sets):
     def action(self, interface):
         data = interface.recv()
 
-        if len(data) > self.ARP_PKT_LEN:
-            return
+        if len(data) <= self.ARP_PKT_LEN:
+            return self.reply_to_arp(data, interface)
+        elif len(data) <= self.NDP_PKT_LEN:
+            return self.reply_to_ndp(data, interface)
 
+    def reply_to_arp(self, data, interface):
         remote_mac, remote_ip, request_ip, op_type, vlan_id = self.extract_arp_info(data)
 
         # Don't send ARP response if the ARP op code is not request
@@ -121,6 +127,29 @@ def action(self, interface):
 
         return
 
+    def reply_to_ndp(self, data, interface):
+        remote_mac, remote_ip, target_ip = self.extract_ndp_info(data)
+
+        target_ip_str = socket.inet_ntop(socket.AF_INET6, target_ip)
+        if target_ip_str in self.ip_sets[interface.name()]:
+            remote_ip_str = socket.inet_ntop(socket.AF_INET6, remote_ip)
+            neigh_adv_pkt = self.generate_neigh_adv(self.ip_sets[interface.name()][target_ip_str], remote_mac, target_ip_str, remote_ip_str)
+            interface.send(neigh_adv_pkt)
+
+        return
+
+    def extract_ndp_info(self, data):
+        vlan_offset = 0
+
+        if len(data) == 90:
+            vlan_offset = 4
+
+        remote_mac = data[6:12]
+        remote_ip = data[22 + vlan_offset:38 + vlan_offset]
+        target_ip = data[62 + vlan_offset:78 + vlan_offset]
+
+        return remote_mac, remote_ip, target_ip
+
     def extract_arp_info(self, data):
         # remote_mac, remote_ip, request_ip, op_type
         rem_ip_start = 28
@@ -151,6 +180,13 @@ def generate_arp_reply(self, local_mac, remote_mac, local_ip, remote_ip, vlan_id
 
         return eth_hdr + self.arp_chunk + local_mac + local_ip + remote_mac + remote_ip + self.arp_pad
 
+    def generate_neigh_adv(self, local_mac, remote_mac, target_ip, remote_ip):
+        neigh_adv_pkt = Ether(src=local_mac, dst=remote_mac)/IPv6(src=target_ip, dst=remote_ip)
+        neigh_adv_pkt /= ICMPv6ND_NA(tgt=target_ip, R=0, S=1, O=1)
+        neigh_adv_pkt /= ICMPv6NDOptDstLLAddr(lladdr=local_mac)
+
+        return neigh_adv_pkt
+
 def parse_args():
     parser = argparse.ArgumentParser(description='ARP autoresponder')
     parser.add_argument('--conf', '-c', type=str, dest='conf', default='/tmp/from_t1.json', help='path to json file with configuration')