109 lines
3.5 KiB
Python
Executable File
109 lines
3.5 KiB
Python
Executable File
#!/usr/bin/env python3
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# Multicast client
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# Adapted from: http://chaos.weblogs.us/archives/164
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import socket
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import os
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from os import path
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import struct
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ANY = "0.0.0.0"
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MCAST_ADDR = "239.192.76.84"
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MCAST_PORT = 1954
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# Create a UDP socket
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sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP) # IPPROTO_UDP could just be 0
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# Allow multiple sockets to use the same PORT number
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sock.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)
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sock.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEPORT,1)
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# Bind to the port that we know will receive multicast data
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sock.bind((ANY,MCAST_PORT))
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# Tell the kernel that we want to add ourselves to a multicast group
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# The address for the multicast group is the third param
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status = sock.setsockopt(socket.IPPROTO_IP,
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socket.IP_ADD_MEMBERSHIP,
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socket.inet_aton(MCAST_ADDR) + socket.inet_aton(ANY))
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while 1:
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data, addr = sock.recvfrom(1024)
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if len(data) < 4: continue
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data = data[4:] # Trim down to LLAP packet (not "frame")
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if len(data) < 3: continue
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llap_dest_node = data[0]
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llap_src_node = data[1]
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llap_proto_type = data[2]
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data = data[3:] # Trim down to LLAP payload
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if llap_proto_type == 1:
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# ddp, short
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if len(data) < 5: continue
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ddp_len, ddp_dest_socket, ddp_src_socket, ddp_proto_type = struct.unpack_from('>HBBB', data)
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data = data[5:ddp_len]
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elif llap_proto_type == 2:
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# ddp, long (what should we do with this extra information?)
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if len(data) < 13: continue
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ddp_len, ddp_cksum, ddp_dest_net, ddp_src_net, ddp_dest_node, ddp_src_node, ddp_dest_socket, ddp_src_socket, ddp_proto_type = struct.unpack_from('>4H5B', data)
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ddp_hop_count = (ddp_len >> 10) & 0xF
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ddp_len &= 0x3FF
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data = data[13:ddp_len]
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print(ddp_src_net, ddp_dest_net)
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else:
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# llap control packet -- can probably ignore!
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continue
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print(f'datagram {llap_proto_type} {llap_src_node}:{ddp_src_socket}->{llap_dest_node}:{ddp_dest_socket}')
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if ddp_proto_type == 2: # NBP
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if len(data) < 2: continue
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nbp_func = data[0] >> 4
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nbp_tuple_cnt = data[0] & 0xF
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nbp_id = data[1]
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data = data[2:]
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nbp_tuples = []
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while data and len(nbp_tuples) < nbp_tuple_cnt:
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if len(data) < 5: break
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this_tuple = list(struct.unpack_from('>HBBB', data))
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data = data[5:]
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for i in range(3):
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# This should be coded more defensively, perhaps using exceptions
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this_tuple.append(data[1:1+data[0]].decode('mac_roman'))
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data = data[1+data[0]:]
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nbp_tuples.append(tuple(this_tuple))
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print(' NBP func', nbp_func, 'id', nbp_id)
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for t in nbp_tuples:
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print(f' net:node:sock={t[0]}:{t[1]}:{t[2]} enum={t[3]} object:type@zone={t[4]}:{t[5]}@{t[6]}')
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elif ddp_proto_type == 10: # ATBOOT
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if len(data) < 2:
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print('malformed short packet %r' % data.hex())
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continue
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boot_type, boot_vers = struct.unpack_from('>BB', data)
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data = data[2:]
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if boot_type == 1:
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print(' ATBOOT "syn"', data.hex())
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elif boot_type == 2:
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print(' ATBOOT "ack"', data.hex())
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elif boot_type == 3:
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print(' ATBOOT image request', data.hex())
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elif boot_type == 4:
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print(' ATBOOT image reply', data.hex())
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else:
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print(' ' + data.hex())
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else:
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print('Totally unknown DDP type', ddp_proto_type)
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print(' ' + data.hex())
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