mirror of
https://github.com/uhi22/pyPLC.git
synced 2024-11-20 01:13:58 +00:00
98 lines
3.9 KiB
Python
Executable file
98 lines
3.9 KiB
Python
Executable file
|
|
# This module "prints" log messages to UDP broadcasts to port 514.
|
|
|
|
from helpers import prettyMac
|
|
|
|
class udplog():
|
|
def fillMac(self, macbytearray, position=6): # position 6 is the source MAC
|
|
for i in range(0, 6):
|
|
self.EthTxFrame[6+i] = macbytearray[i]
|
|
|
|
|
|
def log(self, s):
|
|
# return # activate this line to disable the logging completely
|
|
#
|
|
# The frame format follows the Syslog protocol, https://en.wikipedia.org/wiki/Syslog
|
|
# Level consists of
|
|
# Facility = 1 = "user"
|
|
# Severity = 7 = "debug"
|
|
return
|
|
strLevel="<15>"
|
|
# The String to be logged. Terminated by 00.
|
|
strMessage=s+"\0"
|
|
|
|
lenPayLoad = 4 + len(strMessage) # length of level is 4
|
|
|
|
buffer=bytearray(lenPayLoad+28) # prepare the IPv4 buffer. Including 28 bytes IP header.
|
|
# syslog level (4 characters)
|
|
for i in range(0, len(strLevel)):
|
|
buffer[28+i] = ord(strLevel[i])
|
|
# the message, terminated by 00
|
|
for i in range(0, len(strMessage)):
|
|
buffer[32+i] = ord(strMessage[i])
|
|
buffer[0] = 0x45 # IP header len
|
|
buffer[1] = 0
|
|
iplen=len(buffer) # including IP header and all payload
|
|
buffer[2] = iplen >> 8
|
|
buffer[3] = (iplen & 0xff)
|
|
ipid = 0x8a9f
|
|
buffer[4] = ipid >> 8
|
|
buffer[5] = (ipid & 0xff)
|
|
fragoffset = 0
|
|
buffer[6] = fragoffset >> 8
|
|
buffer[7] = (fragoffset & 0xff)
|
|
buffer[8] = 0x80 # ttl
|
|
buffer[9] = 0x11 # proto
|
|
checksum = 0
|
|
buffer[10] = checksum >> 8
|
|
buffer[11] = (checksum & 0xff)
|
|
# source ip 4 bytes
|
|
buffer[12] = 192 # does this really matter?
|
|
buffer[13] = 168
|
|
buffer[14] = self.ownMac[4] # quick&dirty: we just fill the last two bytes of the MAC here.
|
|
buffer[15] = self.ownMac[5] #
|
|
# destination ip 4 bytes: broadcast
|
|
buffer[16] = 0xff
|
|
buffer[17] = 0xff
|
|
buffer[18] = 0xff
|
|
buffer[19] = 0xff
|
|
# source port
|
|
buffer[20] = 0xff
|
|
buffer[21] = 0x95
|
|
# destination port. 0x0202 = 514 = the official Syslog UDP port
|
|
buffer[22] = 0x02
|
|
buffer[23] = 0x02
|
|
udplen = lenPayLoad + 8 # payload plus 8 byte udp header
|
|
buffer[24] = udplen >> 8
|
|
buffer[25] = (udplen & 0xff)
|
|
udpchecksum = 0 # checksum 0 has the special meaning: no checksum. Receiver ignores it.
|
|
buffer[26] = udpchecksum >> 8
|
|
buffer[27] = (udpchecksum & 0xff)
|
|
|
|
|
|
|
|
# packs the IP packet into an ethernet packet
|
|
self.EthTxFrame = bytearray(len(buffer) + 6 + 6 + 2) # Ethernet header needs 14 bytes:
|
|
# 6 bytes destination MAC
|
|
# 6 bytes source MAC
|
|
# 2 bytes EtherType
|
|
# fill the destination MAC with broadcast MAC
|
|
self.EthTxFrame[0] = 0xFF
|
|
self.EthTxFrame[1] = 0xFF
|
|
self.EthTxFrame[2] = 0xFF
|
|
self.EthTxFrame[3] = 0xFF
|
|
self.EthTxFrame[4] = 0xFF
|
|
self.EthTxFrame[5] = 0xFF
|
|
self.fillMac(self.ownMac) # bytes 6 to 11 are the source MAC
|
|
self.EthTxFrame[12] = 0x08 # 0800 is IPv4
|
|
self.EthTxFrame[13] = 0x00
|
|
for i in range(0, len(buffer)): # copy the IPv4 buffer content into the Ethernet buffer
|
|
self.EthTxFrame[14+i] = buffer[i]
|
|
self.transmit(self.EthTxFrame) # and finally transmit the Ethernet frame
|
|
|
|
|
|
def __init__(self, transmitCallback, addressManager):
|
|
self.transmit = transmitCallback
|
|
self.addressManager = addressManager
|
|
self.ownMac = self.addressManager.getLocalMacAddress()
|
|
print("udplog started with ownMac " + prettyMac(self.ownMac))
|