| from scapy.all import * |
| |
| conf.verb = 0 # Disable Scapy verbosity |
| conf.checkIPaddr = 0 # Don't check response packets for matching destination IPs |
| |
| class DHCPTest: |
| |
| def __init__(self, seed_ip = '192.168.1.1', iface = 'veth0'): |
| self.seed_ip = seed_ip |
| self.seed_mac = self.ipToMac(self.seed_ip) |
| self.iface = iface |
| self.mac_map = {} |
| self.mac_inverse_map = {} |
| |
| def is_mcast(self, ip): |
| mcast_octet = (atol(ip) >> 24) & 0xff |
| return True if mcast_octet >= 224 and mcast_octet <= 239 else False |
| |
| def discover(self, mac = None, update_seed = False): |
| '''Send a DHCP discover/offer''' |
| |
| if mac is None: |
| mac = self.seed_mac |
| if update_seed: |
| self.seed_ip = self.incIP(self.seed_ip) |
| self.seed_mac = self.ipToMac(self.seed_ip) |
| mac = self.seed_mac |
| |
| chmac = self.macToChaddr(mac) |
| L2 = Ether(dst="ff:ff:ff:ff:ff:ff", src=mac) |
| L3 = IP(src="0.0.0.0", dst="255.255.255.255") |
| L4 = UDP(sport=68, dport=67) |
| L5 = BOOTP(chaddr=chmac) |
| L6 = DHCP(options=[("message-type","discover"),"end"]) |
| resp = srp1(L2/L3/L4/L5/L6, filter="udp and port 68", timeout=5, iface=self.iface) |
| try: |
| srcIP = resp.yiaddr |
| serverIP = resp.siaddr |
| except AttributeError: |
| print("Failed to acquire IP via DHCP for %s on interface %s" %(mac, self.iface)) |
| return (None, None) |
| |
| subnet_mask = "0.0.0.0" |
| for x in resp.lastlayer().options: |
| if(x == 'end'): |
| break |
| op,val = x |
| if(op == "subnet_mask"): |
| subnet_mask = val |
| elif(op == 'server_id'): |
| server_id = val |
| |
| L5 = BOOTP(chaddr=chmac, yiaddr=srcIP) |
| L6 = DHCP(options=[("message-type","request"), ("server_id",server_id), |
| ("subnet_mask",subnet_mask), ("requested_addr",srcIP), "end"]) |
| srp(L2/L3/L4/L5/L6, filter="udp and port 68", timeout=5, iface=self.iface) |
| self.mac_map[mac] = (srcIP, serverIP) |
| self.mac_inverse_map[srcIP] = (mac, serverIP) |
| return (srcIP, serverIP) |
| |
| def discover_next(self): |
| '''Send next dhcp discover/request with updated mac''' |
| return self.discover(update_seed = True) |
| |
| def release(self, ip): |
| '''Send a DHCP discover/offer''' |
| if ip is None: |
| return False |
| if not self.mac_inverse_map.has_key(ip): |
| return False |
| mac, server_ip = self.mac_inverse_map[ip] |
| chmac = self.macToChaddr(mac) |
| L2 = Ether(dst="ff:ff:ff:ff:ff:ff", src=mac) |
| L3 = IP(src="0.0.0.0", dst="255.255.255.255") |
| L4 = UDP(sport=68, dport=67) |
| L5 = BOOTP(chaddr=chmac, ciaddr = ip) |
| L6 = DHCP(options=[("message-type","release"), ("server_id", server_ip), "end"]) |
| sendp(L2/L3/L4/L5/L6, iface = self.iface) |
| del self.mac_map[mac] |
| del self.mac_inverse_map[ip] |
| return True |
| |
| def macToChaddr(self, mac): |
| rv = [] |
| mac = mac.split(":") |
| for x in mac: |
| rv.append(chr(int(x, 16))) |
| return reduce(lambda x,y: x + y, rv) |
| |
| def get_ip(self, mac): |
| if self.mac_map.has_key(mac): |
| return self.mac_map[mac] |
| return (None, None) |
| |
| def get_mac(self, ip): |
| if self.mac_inverse_map.has_key(ip): |
| return self.mac_inverse_map[ip] |
| return (None, None) |
| |
| def ipToMac(self, ip): |
| '''Generate a mac from a ip''' |
| |
| mcast = self.is_mcast(ip) |
| mac = "01:00:5e" if mcast == True else "00:00:00" |
| octets = ip.split(".") |
| for x in range(1,4): |
| num = str(hex(int(octets[x]))) |
| num = num.split("x")[1] |
| if len(num) < 2: |
| num = "0" + str(num) |
| mac += ":" + num |
| return mac |
| |
| def incIP(self, ip, n=1): |
| '''Increment an IP''' |
| |
| if n < 1: |
| return ip |
| o = ip.split(".") |
| for ii in range(3,-1,-1): |
| if int(o[ii]) < 255: |
| o[ii] = str(int(o[ii]) + 1) |
| break |
| else: |
| o[ii] = str(0) |
| |
| n -= 1 |
| return self.incIP(".".join(o), n) |