| Chetan Gaonker | b2bd824 | 2016-03-03 15:39:24 -0800 | [diff] [blame^] | 1 | from scapy.all import * |
| 2 | |
| 3 | conf.verb = 0 # Disable Scapy verbosity |
| 4 | conf.checkIPaddr = 0 # Don't check response packets for matching destination IPs |
| 5 | |
| 6 | class DHCPTest: |
| 7 | |
| 8 | def __init__(self, seed_ip = '192.168.1.1', iface = 'veth0'): |
| 9 | self.seed_ip = seed_ip |
| 10 | self.seed_mac = self.ipToMac(self.seed_ip) |
| 11 | self.iface = iface |
| 12 | self.mac_map = {} |
| 13 | self.mac_inverse_map = {} |
| 14 | |
| 15 | def is_mcast(self, ip): |
| 16 | mcast_octet = (atol(ip) >> 24) & 0xff |
| 17 | return True if mcast_octet >= 224 and mcast_octet <= 239 else False |
| 18 | |
| 19 | def send(self, mac = None, update_seed = False): |
| 20 | '''Send a DHCP discover/offer''' |
| 21 | |
| 22 | if mac is None: |
| 23 | mac = self.seed_mac |
| 24 | if update_seed: |
| 25 | self.seed_ip = self.incIP(self.seed_ip) |
| 26 | self.seed_mac = self.ipToMac(self.seed_ip) |
| 27 | mac = self.seed_mac |
| 28 | |
| 29 | chmac = self.macToChaddr(mac) |
| 30 | L2 = Ether(dst="ff:ff:ff:ff:ff:ff", src=mac) |
| 31 | L3 = IP(src="0.0.0.0", dst="255.255.255.255") |
| 32 | L4 = UDP(sport=68, dport=67) |
| 33 | L5 = BOOTP(chaddr=chmac) |
| 34 | L6 = DHCP(options=[("message-type","discover"),"end"]) |
| 35 | resp = srp1(L2/L3/L4/L5/L6, filter="udp and port 68", timeout=5, iface=self.iface) |
| 36 | try: |
| 37 | srcIP = resp.yiaddr |
| 38 | serverIP = resp.siaddr |
| 39 | except AttributeError: |
| 40 | print("Failed to acquire IP via DHCP for %s on interface %s" %(mac, self.iface)) |
| 41 | return (None, None) |
| 42 | |
| 43 | for x in resp.lastlayer().options: |
| 44 | if(x == 'end'): |
| 45 | break |
| 46 | op,val = x |
| 47 | if(op == "subnet_mask"): |
| 48 | subnet_mask = val |
| 49 | elif(op == 'server_id'): |
| 50 | server_id = val |
| 51 | |
| 52 | L5 = BOOTP(chaddr=chmac, yiaddr=srcIP) |
| 53 | L6 = DHCP(options=[("message-type","request"), ("server_id",server_id), |
| 54 | ("subnet_mask",subnet_mask), ("requested_addr",srcIP), "end"]) |
| 55 | srp1(L2/L3/L4/L5/L6, filter="udp and port 68", timeout=5, iface=self.iface) |
| 56 | self.mac_map[mac] = (srcIP, serverIP) |
| 57 | self.mac_inverse_map[srcIP] = (mac, serverIP) |
| 58 | return (srcIP, serverIP) |
| 59 | |
| 60 | def send_next(self): |
| 61 | '''Send next dhcp discover/request with updated mac''' |
| 62 | |
| 63 | return self.send(update_seed = True) |
| 64 | |
| 65 | def macToChaddr(self, mac): |
| 66 | rv = [] |
| 67 | mac = mac.split(":") |
| 68 | for x in mac: |
| 69 | rv.append(chr(int(x, 16))) |
| 70 | return reduce(lambda x,y: x + y, rv) |
| 71 | |
| 72 | def get_ip(self, mac): |
| 73 | if self.mac_map.has_key(mac): |
| 74 | return self.mac_map[mac] |
| 75 | return (None, None) |
| 76 | |
| 77 | def get_mac(self, ip): |
| 78 | if self.mac_inverse_map.has_key(ip): |
| 79 | return self.mac_inverse_map[ip] |
| 80 | return (None, None) |
| 81 | |
| 82 | def ipToMac(self, ip): |
| 83 | '''Generate a mac from a ip''' |
| 84 | |
| 85 | mcast = self.is_mcast(ip) |
| 86 | mac = "01:00:5e" if mcast == True else "00:00:00" |
| 87 | octets = ip.split(".") |
| 88 | for x in range(1,4): |
| 89 | num = str(hex(int(octets[x]))) |
| 90 | num = num.split("x")[1] |
| 91 | if len(num) < 2: |
| 92 | num = "0" + str(num) |
| 93 | mac += ":" + num |
| 94 | return mac |
| 95 | |
| 96 | def incIP(self, ip, n=1): |
| 97 | '''Increment an IP''' |
| 98 | |
| 99 | if n < 1: |
| 100 | return ip |
| 101 | o = ip.split(".") |
| 102 | for ii in range(3,-1,-1): |
| 103 | if int(o[ii]) < 255: |
| 104 | o[ii] = str(int(o[ii]) + 1) |
| 105 | break |
| 106 | else: |
| 107 | o[ii] = str(0) |
| 108 | |
| 109 | n -= 1 |
| 110 | return self.incIP(".".join(o), n) |