mirror of
https://github.com/uhi22/pyPLC.git
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91 lines
3.2 KiB
Python
Executable file
91 lines
3.2 KiB
Python
Executable file
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# This module "prints" log messages to UDP broadcasts to port 514.
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from helpers import prettyMac
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class udplog():
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def fillMac(self, macbytearray, position=6): # position 6 is the source MAC
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for i in range(0, 6):
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self.EthTxFrame[6+i] = macbytearray[i]
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def log(self, s):
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strLevel="<15>"
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strMessage=s+"\0"
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lenPayLoad = 4 + len(strMessage)
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buffer=bytearray(lenPayLoad+28)
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# syslog level (4 characters)
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for i in range(0, len(strLevel)):
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buffer[28+i] = ord(strLevel[i])
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# the message, terminated by 00
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for i in range(0, len(strMessage)):
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buffer[32+i] = ord(strMessage[i])
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buffer[0] = 0x45 # IP header len
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buffer[1] = 0
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iplen=len(buffer) # including IP header and all payload
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buffer[2] = iplen >> 8
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buffer[3] = (iplen & 0xff)
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ipid = 0x8a9f
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buffer[4] = ipid >> 8
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buffer[5] = (ipid & 0xff)
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fragoffset = 0
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buffer[6] = fragoffset >> 8
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buffer[7] = (fragoffset & 0xff)
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buffer[8] = 0x80 # ttl
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buffer[9] = 0x11 # proto
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checksum = 0
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buffer[10] = checksum >> 8
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buffer[11] = (checksum & 0xff)
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# source ip 4 bytes
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buffer[12] = 192 # does this really matter?
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buffer[13] = 168
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buffer[14] = 2
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buffer[15] = 222
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# destination ip 4 bytes: broadcast
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buffer[16] = 0xff
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buffer[17] = 0xff
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buffer[18] = 0xff
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buffer[19] = 0xff
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# source port
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buffer[20] = 0xff
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buffer[21] = 0x95
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# destination port
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buffer[22] = 0x02
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buffer[23] = 0x02
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udplen = lenPayLoad + 8 # payload plus 8 byte udp header
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buffer[24] = udplen >> 8
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buffer[25] = (udplen & 0xff)
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udpchecksum = 0
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buffer[26] = udpchecksum >> 8
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buffer[27] = (udpchecksum & 0xff)
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# packs the IP packet into an ethernet packet
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self.EthTxFrame = bytearray(len(buffer) + 6 + 6 + 2) # Ethernet header needs 14 bytes:
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# 6 bytes destination MAC
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# 6 bytes source MAC
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# 2 bytes EtherType
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# fill the destination MAC with broadcast MAC
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self.EthTxFrame[0] = 0xFF
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self.EthTxFrame[1] = 0xFF
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self.EthTxFrame[2] = 0xFF
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self.EthTxFrame[3] = 0xFF
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self.EthTxFrame[4] = 0xFF
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self.EthTxFrame[5] = 0xFF
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self.fillMac(self.ownMac) # bytes 6 to 11 are the source MAC
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self.EthTxFrame[12] = 0x08 # 0800 is IPv4
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self.EthTxFrame[13] = 0x00
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for i in range(0, len(buffer)):
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self.EthTxFrame[14+i] = buffer[i]
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self.transmit(self.EthTxFrame)
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def __init__(self, transmitCallback, addressManager):
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self.transmit = transmitCallback
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self.addressManager = addressManager
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self.ownMac = self.addressManager.getLocalMacAddress()
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print("udplog started with ownMac " + prettyMac(self.ownMac))
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