61 lines
1.8 KiB
Python
Executable File
61 lines
1.8 KiB
Python
Executable File
#!/usr/bin/python
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# Copyright 2013-present Barefoot Networks, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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# Author: Brent Stephens
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#
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from scapy.all import sniff, sendp
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from scapy.all import Packet
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from scapy.all import ShortField, IntField, LongField, BitField
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import sys
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import struct
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def handle_pkt(pkt):
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pkt = str(pkt)
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if len(pkt) < 13: return
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preamble = pkt[:8]
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preamble_exp = "\x00" * 8
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if preamble != preamble_exp: return
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axonType = pkt[8]
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if axonType != "\x00": return
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axonLength = struct.unpack("!H", pkt[9:11])[0]
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fwdHopCount = struct.unpack("B", pkt[11])[0]
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revHopCount = struct.unpack("B", pkt[12])[0]
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if fwdHopCount != 0:
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print 'received a packet that has not been fully forwarded'
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if revHopCount <= 0:
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print 'received a packet that has no reverse hops'
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if axonLength != 2 + fwdHopCount + revHopCount:
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print 'received a packet with either an incorrect axonLength, fwdHopCount, or revHopCount'
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msg = pkt[11 + axonLength:]
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print msg
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sys.stdout.flush()
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# Optional debugging
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#print 'axonLength:', axonLength
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#print 'fwdHopCount:', fwdHopCount
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#print 'revHopCount:', revHopCount
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#print pkt
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def main():
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sniff(iface = "eth0",
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prn = lambda x: handle_pkt(x))
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if __name__ == '__main__':
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main()
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