2016-08-10 16:28:29 +02:00
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#!/usr/bin/env python3
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"""
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Netflow V9 collector implementation in Python 3.
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Created for learning purposes and unsatisfying alternatives.
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(C) 2016 Dominik Pataky <dom@netdecorator.org>
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"""
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from collections import namedtuple
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import socket
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import struct
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HOST = '0.0.0.0'
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PORT = 9001
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field_types = {
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1: 'IN_BYTES',
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2: 'IN_PKTS',
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3: 'FLOWS',
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4: 'PROTOCOL',
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5: 'SRC_TOS',
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6: 'TCP_FLAGS',
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7: 'L4_SRC_PORT',
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8: 'IPV4_SRC_ADDR',
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9: 'SRC_MASK',
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10: 'INPUT_SNMP',
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11: 'L4_DST_PORT',
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12: 'IPV4_DST_ADDR',
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13: 'DST_MASK',
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14: 'OUTPUT_SNMP',
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15: 'IPV4_NEXT_HOP',
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16: 'SRC_AS',
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17: 'DST_AS',
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18: 'BGP_IPV4_NEXT_HOP',
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19: 'MUL_DST_PKTS',
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20: 'MUL_DST_BYTES',
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21: 'LAST_SWITCHED',
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22: 'FIRST_SWITCHED',
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23: 'OUT_BYTES',
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24: 'OUT_PKTS',
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25: 'MIN_PKT_LNGTH',
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26: 'MAX_PKT_LNGTH',
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27: 'IPV6_SRC_ADDR',
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28: 'IPV6_DST_ADDR',
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29: 'IPV6_SRC_MASK',
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30: 'IPV6_DST_MASK',
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31: 'IPV6_FLOW_LABEL',
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32: 'ICMP_TYPE',
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33: 'MUL_IGMP_TYPE',
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34: 'SAMPLING_INTERVAL',
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35: 'SAMPLING_ALGORITHM',
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36: 'FLOW_ACTIVE_TIMEOUT',
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37: 'FLOW_INACTIVE_TIMEOUT',
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38: 'ENGINE_TYPE',
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39: 'ENGINE_ID',
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40: 'TOTAL_BYTES_EXP',
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41: 'TOTAL_PKTS_EXP',
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42: 'TOTAL_FLOWS_EXP',
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# 43 vendor proprietary
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44: 'IPV4_SRC_PREFIX',
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45: 'IPV4_DST_PREFIX',
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46: 'MPLS_TOP_LABEL_TYPE',
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47: 'MPLS_TOP_LABEL_IP_ADDR',
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48: 'FLOW_SAMPLER_ID',
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49: 'FLOW_SAMPLER_MODE',
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50: 'NTERVAL',
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# 51 vendor proprietary
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52: 'MIN_TTL',
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53: 'MAX_TTL',
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54: 'IPV4_IDENT',
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55: 'DST_TOS',
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56: 'IN_SRC_MAC',
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57: 'OUT_DST_MAC',
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58: 'SRC_VLAN',
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59: 'DST_VLAN',
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60: 'IP_PROTOCOL_VERSION',
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61: 'DIRECTION',
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62: 'IPV6_NEXT_HOP',
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63: 'BPG_IPV6_NEXT_HOP',
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64: 'IPV6_OPTION_HEADERS',
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# 65-69 vendor proprietary
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70: 'MPLS_LABEL_1',
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71: 'MPLS_LABEL_2',
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72: 'MPLS_LABEL_3',
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73: 'MPLS_LABEL_4',
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74: 'MPLS_LABEL_5',
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75: 'MPLS_LABEL_6',
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76: 'MPLS_LABEL_7',
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77: 'MPLS_LABEL_8',
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78: 'MPLS_LABEL_9',
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79: 'MPLS_LABEL_10',
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80: 'IN_DST_MAC',
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81: 'OUT_SRC_MAC',
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82: 'IF_NAME',
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83: 'IF_DESC',
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84: 'SAMPLER_NAME',
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85: 'IN_PERMANENT_BYTES',
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86: 'IN_PERMANENT_PKTS',
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# 87 vendor property
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88: 'FRAGMENT_OFFSET',
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89: 'FORWARDING STATUS',
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}
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2016-08-10 18:55:38 +02:00
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# We need to save the templates our NetFlow device send over time. Templates
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# are not resended every time a flow is sent to the collector.
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templates = []
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2016-08-10 16:28:29 +02:00
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sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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sock.bind((HOST, PORT))
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print("Listening on interface {}:{}".format(HOST, PORT))
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2016-08-10 18:55:38 +02:00
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class DataRecord:
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"""Should hold a 'data' dict with keys=field_type and value.
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"""
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data = {}
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class DataFlowSet:
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"""
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"""
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def __init__(self, data):
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pack = struct.unpack('!HH', data[:4])
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self.template_id = pack[0] # flowset_id is reference to template_id
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self.length = pack[1]
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print("New DataFlowSet with template {}, length {}".format(self.template_id, self.length))
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2016-08-10 16:28:29 +02:00
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class TemplateField:
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2016-08-10 18:55:38 +02:00
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"""
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"""
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def __init__(self, field_type, field_length):
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self.field_type = field_type # integer
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self.field_length = field_length
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class Template:
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"""
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Template = namedtuple('Template', 'template_id field_count')
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"""
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pass
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class TemplateFlowSet:
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"""A template flowset, which holds an id that is used by data flowsets to
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reference back to the template. The template then has fields which hold
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identifiers of data types ("IP_SRC_ADDR", "PKTS"). This way the flow sender
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can dynamically out together data flowsets.
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"""
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def __init__(self, data):
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pack = struct.unpack('!HH', data[:4])
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self.flowset_id = pack[0]
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self.length = pack[1] # total length including this header in bytes
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offset = 4
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field_size = 16 + 16
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while offset != self.length:
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pack = struct.unpack('!HH', data[offset:offset+4])
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template_id = pack[0]
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field_count = pack[1]
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# Set offset to next template_id field
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offset += 4 + (field_count * 4)
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print("id: {}, count: {}, new offset: {}".format(template_id, field_count, offset))
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2016-08-10 16:28:29 +02:00
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class Header:
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"""The header of the flow record.
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"""
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def __init__(self, data):
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pack = struct.unpack('!HHIIII', data)
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self.version = pack[0]
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self.count = pack[1] # number of FlowSets in this record
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self.uptime = pack[2]
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self.timestamp = pack[3]
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self.sequence = pack[4]
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self.source_id = pack[5]
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2016-08-10 16:28:29 +02:00
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2016-08-10 18:55:38 +02:00
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class ExportPacket:
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"""The flow record holds the header and all template and data flowsets.
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"""
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def __init__(self, data):
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self.header = Header(data[:20])
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2016-08-10 18:55:38 +02:00
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flowsets_remaining = self.header.count
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self.templates = []
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self.data = []
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search_offset = 20
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while flowsets_remaining != 0:
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print("data flowsets remaining: {}".format(flowsets_remaining))
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flowset_id = struct.unpack('!H', data[search_offset:search_offset+2])[0]
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if flowset_id == 0: # TemplateFlowSet always have id 0
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tfs = TemplateFlowSet(data[search_offset:])
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search_offset += tfs.length
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else:
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dfs = DataFlowSet(data[search_offset:])
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search_offset += dfs.length
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# Bug in softflowd?
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# https://github.com/djmdjm/softflowd/blob/master/netflow9.c#L477
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flowsets_remaining -= 1
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2016-08-10 16:28:29 +02:00
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def __repr__(self):
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return "<ExportPacket version {} counting {} flowset records>".format(
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self.header.version, self.header.count)
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while 1:
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(data, sender) = sock.recvfrom(8192)
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print("Received data from {}, length {}".format(sender, len(data)))
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2016-08-10 18:55:38 +02:00
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export = ExportPacket(data)
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print(export)
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