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Diffstat (limited to 'fap/dhcpd/server_dhcp.py')
| -rwxr-xr-x | fap/dhcpd/server_dhcp.py | 360 |
1 files changed, 0 insertions, 360 deletions
diff --git a/fap/dhcpd/server_dhcp.py b/fap/dhcpd/server_dhcp.py deleted file mode 100755 index 592e1eb..0000000 --- a/fap/dhcpd/server_dhcp.py +++ /dev/null @@ -1,360 +0,0 @@ -#!/usr/bin/python -# -*- coding: utf-8 -*- - -''' -server_dhcp.py by Jonas "j" Lindstad for The Gathering tech:server - -Used to configure the Juniper EX2200 edge switches with Zero Touch Protocol -License: GPLv2 - -Based on the work of psychomario - https://github.com/psychomario -''' - - -''' - -TODO - - * try/catch around each incomming packet - prevents DHCP-server from crashing if it receives a malformed packet - -''' - -import socket, binascii, IN -from module_craft_option import craft_option # Module that crafts DHCP options -# from module_lease import lease # Module that fetches data from DB and provides data for the lease -from module_lease import lease2 as lease # Module that fetches data from DB and provides data for the lease - - -# Global options - not a pretty hack -options_raw = {} # TODO - not a nice way to do things -option_82_1 = '' -client = '' - - -############# -# FUNCTIONS # -############# - -# Generator for each of the dhcp fields -def split_packet(msg,slices): - for x in slices: - yield msg[:x] - msg = msg[x:] - -# Splits a chunk of hex into a list of hex. (0123456789abcdef => ['01', '23', '45', '67', '89', 'ab', 'cd', 'ef']) -def chunk_hex(hex): - return [hex[i:i+2] for i in range(0, len(hex), 2)] - -# Convert hex IP to string with formated decimal IP. (0a0000ff => 10.0.0.255) -def hex_ip_to_str(hex_ip): - return '.'.join(str(y) for y in map(lambda x: int(x, 16), chunk_hex(hex_ip))) # cast int to str for join - -# formats a MAC address in the format "b827eb9a520f" to "b8:27:eb:9a:52:0f" -def format_hex_mac(hex_mac): - return ':'.join(str(x) for x in chunk_hex(hex_mac)) - -# Formats a 6 byte MAC to a readable string (b'5e\x21\x00r3' => '35:65:21:00:72:33') -def six_byte_mac_to_str(mac): - return ':'.join('%02x' % byte for byte in mac) - -# b'b827eb9a520f' => 'b8:27:eb:9a:52:0f' -def prettyprint_hex_as_str(hex): - return ':'.join('%02x' % byte for byte in binascii.unhexlify(hex)) - -# CIDR notation to subnet string ('25' => '255.255.255.128') -def cidr_to_subnet(cidr): - mask = [0, 0, 0, 0] - for i in range(int(cidr)): - mask[i//8] = mask[i//8] + (1 << (7 - i % 8)) - return '.'.join(str(x) for x in mask) - -# Parses DHCP options - raw = hex options -def parse_options(raw): - print('[%s] --> processing DHCP options' % client) - chunked = chunk_hex(raw) - chunked_length = len(chunked) - pointer = 0 # counter - next option start - options = {} # options dataset - - global options_raw - options_raw = {} # incomming request's options - special_options = [53, 82] - - while True: # Loop over the DHCP options - option = int(chunked[pointer], 16) # option ID (0 => 255) - code = int(chunked[pointer], 16) # option code (0 => 255) # New int for options' ID with correct name. Replaces $option - - length = int(chunked[pointer+1], 16) # option length - option_payload = raw[((pointer+2)*2):((pointer+length+2)*2)] # Contains the payload of the option - without option ID and length - options_raw[code] = option_payload # copying incomming request's options, directly usable in outgoing replies - - asciivalue = binascii.unhexlify(option_payload) # should not contain unreadable characters - - if option in special_options: - if option is 82: - option82_raw = option_payload - options[option] = parse_suboptions(option, option_payload) - elif option is 53: - options[option] = option_payload - # options[option] = 1 # Not adding DHCP DISCOVER to the options list, becouse it will not be used further on - if int(chunked[pointer+2], 16) is 1: - print('[%s] --> option: %s: %s' % (client, option, 'DHCP Discover (will not be used in reply)')) - else: - print('[%s] --> option: %s: %s' % (client, option, asciivalue)) - - else: - options[option] = asciivalue - # TODO: Formating.... Also crap code - try: - if len(asciivalue) > 30: - print('[%s] --> option: %s: %s' % (client, option, asciivalue[:26] + ' [...]')) - else: - print('[%s] --> option: %s: %s' % (client, option, asciivalue)) - except Exception: - if len(asciivalue) > 30: - print('[%s] --> option: %s: %s' % (client, option, prettyprint_hex_as_str(option_payload)[:26] + ' [...]')) - else: - print('[%s] --> option: %s: %s' % (client, option, prettyprint_hex_as_str(option_payload))) - pass - - pointer = pointer + length + 2 # place pointer at the next options' option ID/code field - - if int(chunked[pointer], 16) is 255: # end of DHCP options - should allways last field - print('[%s] --> Finished processing options' % client) - break - return options - -# Parses suboptions -def parse_suboptions(option, raw): - print('[%s] --> processing suboption hook for option %s' % (client, option)) - chunked = chunk_hex(raw) - chunked_length = len(chunked) - pointer = 0 # counter - next option start - dataset = {} - - if option is 82: # Option 82 - custom shit: Setting global variable to list - global option_82_1 - - while True: - length = int(chunked[pointer+1], 16) # option length in bytes - value = raw[4:(length*2)+(4)] - - if option is 82 and int(chunked[0], 16) is 1: # Option 82 - custom shit: Putting data in list - option_82_1 = binascii.unhexlify(value).decode() - - print('[%s] --> suboption %s found - value: "%s"' % (client, int(chunked[0], 16), binascii.unhexlify(value).decode())) # will fail on non-ascii characters - - dataset[int(chunked[0], 16)] = value - pointer = pointer + length + 2 # place pointer at the next options' option ID/code field - if pointer not in chunked: # end of DHCP options - allways last field - print('[%s] --> Finished processing suboption %s' % (client, option)) - break - return dataset - -# Parses and handles DHCP DISCOVER or DHCP REQUEST -def reqparse(message): - data=None - dhcpfields=[1,1,1,1,4,2,2,4,4,4,4,6,10,192,4,message.rfind(b'\xff'),1] - hexmessage=binascii.hexlify(message) - messagesplit=[binascii.hexlify(x) for x in split_packet(message,dhcpfields)] - - global client - client = prettyprint_hex_as_str(messagesplit[11]) - - if messagesplit[11][0:6] != b'44f477': - print('[%s] Client not Juniper - exiting (GIADDR: %s)' % (client, hex_ip_to_str(messagesplit[10]))) - return False - - print('[%s] Parsing DHCP packet from client' % client) - - # - # Logical checks to decide to whether respond or reject - # - if int(hex_ip_to_str(messagesplit[10]).replace('.', '')) is 0: # DHCP request has been forwarded by DHCP relay - A bit haxxy.. - print('[%s] Rejecting to process DHCP packet - not forwarded by DHCP relay' % client) - return False - - - # Process DHCP options - options = parse_options(messagesplit[15]) - - # Option 82 is set in the packet - if 82 not in options: - print('[%s] Rejecting to process DHCP packet - DHCP option 82 not set' % client) - return False - - # 1 = DHCP Discover message (DHCPDiscover). - # 2 = DHCP Offer message (DHCPOffer). - # 3 = DHCP Request message (DHCPRequest). - # 4 = DHCP Decline message (DHCPDecline). - # 5 = DHCP Acknowledgment message (DHCPAck). - # 6 = DHCP Negative Acknowledgment message (DHCPNak). - # 7 = DHCP Release message (DHCPRelease). - # 8 = DHCP Informational message (DHCPInform). - - # Check DHCP request type - if options[53] == b'01': - mode = 'dhcp_discover' - print('[%s] --> DHCP packet type: DHCP DISCOVER' % client) - elif options[53] == b'03': - mode = 'dhcp_request' - print('[%s] --> DHCP packet type: DHCP REQUEST' % client) - elif options[53] == b'04': - print('[%s] --> DHCP packet type: DHCP DECLINE - Not implemented' % client) - return False - elif options[53] == b'05': - print('[%s] --> DHCP packet type: DHCP ACK - Not implemented' % client) - return False - elif options[53] == b'06': - print('[%s] --> DHCP packet type: DHCP NEGATIVE ACK - Not implemented' % client) - return False - elif options[53] == b'07': - print('[%s] --> DHCP packet type: DHCP RELEASE - Not implemented' % client) - return False - elif options[53] == b'08': - print('[%s] --> DHCP packet type: DHCP INFORM - Not implemented' % client) - return False - else: - print('[%s] Rejecting to continue process DHCP packet - option 53 missing' % client) # Small sanity check - return False - - - # - # Packet passes our requirements - # - print('[%s] --> DHCP packet contains option 82 - continues to process' % client) - print('[%s] --> DHCP packet forwarded by relay %s' % (client, hex_ip_to_str(messagesplit[10]))) - print('[%s] --> DHCP XID/Transaction ID: %s' % (client, prettyprint_hex_as_str(messagesplit[4]))) - - # Handle DB request - do DB lookup based on option 82 - print('[%s] --> Looking up in the DB' % (client)) - - option_82_1_pieces = option_82_1.split(':') - - if len(option_82_1_pieces) == 3: - (distro, phy, vlan) = option_82_1.split(':') - print('[%s] --> Query details: distro_name:%s, distro_phy_port:%s' % (client, distro, phy.split('.')[0])) - - lease_identifiers = {'distro_name': distro, 'distro_phy_port': phy.split('.')[0]} - if lease(lease_identifiers).get('hostname') is not False: - l={ - 'hostname': lease(lease_identifiers).get('hostname'), - 'mgmt_v4_addr': lease(lease_identifiers).get('mgmt_v4_addr'), - 'mgmt_v4_gw': lease(lease_identifiers).get('mgmt_v4_gw'), - 'mgmt_v4_cidr': lease(lease_identifiers).get('mgmt_v4_cidr') - } - - # lease_details = lease({'distro_name': distro, 'distro_phy_port': phy[:-2]}).get_dict() - print('[%s] --> Data found, switch exists in DB - ready to craft response' % client) - else: - print('[%s] --> Data not found, switch does not exists in DB' % client) - return False - elif len(option_82_1_pieces) > 0: - print('[%s] --> Option 82 does not contained required syntax (<distro>:<phy_port>:<vlan>)' % client) - print('[%s] --> Option 82: %s' % (client, option_82_1)) - print('[%s] --> Ending request' % client) - return False - else: - print('[%s] Rejecting to continue to process DHCP packet - option 82.1 is empty' % client) - - if mode == 'dhcp_discover': - print('[%s] --> Crafting DHCP OFFER response' % client) - - if mode == 'dhcp_request': - print('[%s] --> Crafting DHCP ACK response' % client) - - print('[%s] --> XID/Transaction ID: %s' % (client, prettyprint_hex_as_str(messagesplit[4]))) - print('[%s] --> Client IP: %s' % (client, l['mgmt_v4_addr'])) - print('[%s] --> DHCP forwarder IP: %s' % (client, l['mgmt_v4_gw'])) - print('[%s] --> Client MAC: %s' % (client, client)) - - data = b'\x02' # Message type - boot reply - data += b'\x01' # Hardware type - ethernet - data += b'\x06' # Hardware address length - 6 octets for MAC - data += b'\x01' # Hops - data += binascii.unhexlify(messagesplit[4]) # XID / Transaction ID - data += b'\x00\x00' # seconds elapsed - 1 second - data += b'\x80\x00' # BOOTP flags - broadcast (unicast: 0x0000) - data += b'\x00'*4 # Client IP address - data += socket.inet_aton(l['mgmt_v4_addr']) # New IP to client - data += socket.inet_aton(dhcp_server_address) # Next server IP address - data += socket.inet_aton(l['mgmt_v4_gw']) # Relay agent IP - DHCP forwarder - data += binascii.unhexlify(messagesplit[11]) # Client MAC - data += b'\x00'*202 # Client hardware address padding (10) + Server hostname (64) + Boot file name (128) - data += b'\x63\x82\x53\x63' # Magic cookie - - # - # Craft DHCP options - # - print('[%s] --> Completed DHCP header structure, building DHCP options' % client) - - if mode == 'dhcp_discover': - print('[%s] --> Option 53 (DHCP OFFER): 2' % client) - data += craft_option(53).raw_hex(b'\x02') # Option 53 - DHCP OFFER - - if mode == 'dhcp_request': - print('[%s] --> Option 53 (DHCP ACK): 5' % client) - data += craft_option(53).raw_hex(b'\x05') # Option 53 - DHCP ACK - - data += craft_option(54).bytes(socket.inet_aton(dhcp_server_address)) # Option 54 - DHCP server identifier - print('[%s] --> Option 54 (DHCP server identifier): %s' % (client, dhcp_server_address)) - - data += craft_option(51).raw_hex(b'\x00\x00\xa8\xc0') # Option 51 - Lease time left padded with "0" - print('[%s] --> Option 51 (Lease time): %s' % (client, '43200 (12 hours)')) - - data += craft_option(1).ip(cidr_to_subnet(l['mgmt_v4_cidr'])) # Option 1 - Subnet mask - print('[%s] --> Option 1 (subnet mask): %s' % (client, cidr_to_subnet(l['mgmt_v4_cidr']))) - - data += craft_option(3).ip(l['mgmt_v4_gw']) # Option 3 - Default gateway (set to DHCP forwarders IP) - print('[%s] --> Option 3 (default gateway): %s' % (client, l['mgmt_v4_gw'])) - - data += craft_option(150).bytes(socket.inet_aton(dhcp_server_address)) # Option 150 - TFTP Server. Used as target for the Zero Touch Protocol. Not necessarily TFTP protocol used. - print('[%s] --> Option 150 (Cisco proprietary TFTP server(s)): %s' % (client, dhcp_server_address)) - - # http://www.juniper.net/documentation/en_US/junos13.2/topics/concept/software-image-and-configuration-automatic-provisioning-understanding.html - data += craft_option(43).bytes(craft_option(0).string(target_junos_file) + craft_option(1).string('/tg-edge/' + l['hostname']) + craft_option(3).string('http')) # Option 43 - ZTP - print('[%s] --> Option 43 (Vendor-specific option):' % client) - print('[%s] --> Suboption 0: %s' % (client, target_junos_file)) - print('[%s] --> Suboption 1: %s' % (client, '/tg-edge/' + l['hostname'])) - print('[%s] --> Suboption 3: %s' % (client, 'http')) - - data += b'\xff' - - lease(lease_identifiers).set('current_mac', client) # updates MAC in DB - - return data - -if __name__ == "__main__": - interface = b'eth0' - dhcp_server_address = '185.12.59.11' - target_junos_file = '/files/jinstall-ex-2200-14.1X53-D15.2-domestic-signed.tgz' - - # Setting up the server, and how it will communicate - s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) # IPv4 UDP socket - s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) - s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1) - s.setsockopt(socket.SOL_SOCKET, 25, interface) - s.bind(('', 67)) - - # Starting the whole loop - print('Starting main loop') - while True: #main loop - try: - message, addressf = s.recvfrom(8192) - # print(message) - if message.startswith(b'\x01'): # UDP payload is DHCP request (discover, request, release) - if addressf[0] == '0.0.0.0': - # print('[%s] DHCP broadcast - unsupported' % client) - reply_to = '<broadcast>' - else: - print('[%s] DHCP unicast - DHCP forwarding' % client) - reply_to = addressf[0] # senders (DHCP forwarders) IP - # print(addressf[0]) - # reply_to = '10.0.0.1' - data=reqparse(message) # Parse the DHCP request - if data: - print('[%s] --> replying to %s' % (client, reply_to)) - s.sendto(data, (reply_to, 67)) # Sends reply - print('') - except KeyboardInterrupt: - exit() |