def genframe(fid, data, adulterate = False):
crc = frame.generateFCS(data)
outdata = data + crc
l = len(outdata)
if len(outdata) % 2 == 1:
outdata += "\xFF"
if adulterate:
# corrupt the frame
outdata = outdata[:2] + '\x17' + outdata[3:]
fid.write("1 ")
else:
fid.write("0 ")
fid.write("%d " % l)
fid.write("%4.4X " % l)
for i in range((l+1) / 2):
d1 = struct.unpack('B', outdata[2*i])[0]
d2 = struct.unpack('B', outdata[2*i+1])[0]
fid.write("%2.2X%2.2X " % (d1, d2))
fid.write('\n')
def generateCRC(data):
""" Takes in data and appends the crc
"""
# create the string:
d = ""
for i in data:
d += chr(i)
fcs = frame.generateFCS(d)
return [ord(fcs[0]), ord(fcs[1]), ord(fcs[2]), ord(fcs[3])]
def writePacketsToFile(pktlist, ofile,
update = True, fcsappend = False):
""" take a list of packet bytes
and writes them to the indicated file """
# segment packet strings into lists of bytes
for da in pktlist:
# now we have the output packets in numerical form; perform the update
# of the ip sequence and then the relevant header checksum update
if update:
da[19] = 0
da[20] = 0
# zero udp chksum
da[40] = 0
da[41] = 0
updateIPHeader(da)
# generate fcs
if fcsappend:
dastr = "".join([chr(x) for x in da])
crc = frame.generateFCS(dastr)
da = n.resize(da, len(da)+4)
da[-4] = ord(crc[0])
da[-3] = ord(crc[1])
da[-2] = ord(crc[2])
da[-1] = ord(crc[3])
# now we print our normal format
ofile.write("%d " % (len(da)/2 + 1))
ofile.write("%4.4X " % (len(da)))
for i in range(len(da) / 2):
ofile.write("%2.2X%2.2X " % (da[i*2], da[i*2+1]))
ofile.write('\n')
def genframe(data, prespace = 5, extracrap = 0):
""" write the string data to the files as a frame,
appending the proper length data and computing the crc
"""
# write as input
for i in range(prespace):
dinfid.write("0 0000\n")
l = len(data)
dinfid.write("1 %4.4X\n" % l)
din = data + '\x00'
for i in range((l+1)/2):
dinfid.write("1 %2.2X%2.2X\n" % (ord(din[i*2]),
ord(din[i*2+1])))
for i in range(extracrap):
dinfid.write("1 0000\n")
dinfid.write("0 0000\n")
# write as output
crc = frame.generateFCS(data)
outdata = data + crc
lo = len(outdata)
doutfid.write("%d " % lo)
doutfid.write("%4.4X " % lo)
dout = outdata + '\x00'
for i in range((lo + 1)/2):
doutfid.write('%2.2X%2.2X ' % (ord(dout[i*2]),
ord(dout[i*2+1])))
doutfid.write('\n')
bytestr = ''.join(s.split(' '))
N = len(bytestr)
da = n.zeros(N/2, n.uint8)
for i in range(N/2):
wordstr = bytestr[i*2:(i+1)*2]
#print wordstr, len(wordstr), i, N, N/4
da[i] = int(wordstr, 16)
# now we have the output packets in numerical form; perform the update
# of the ip sequence and then the relevant header checksum update
dastr = "".join([chr(x) for x in da])
crc = frame.generateFCS(dastr)
da = n.resize(da, len(da)+4)
da[-4] = ord(crc[0])
da[-3] = ord(crc[1])
da[-2] = ord(crc[2])
da[-1] = ord(crc[3])
# now we print our normal format
ofile.write("%d " % (len(da)/2 + 1))
ofile.write("%4.4X " % len(da))
for i in range(len(da) / 2):
ofile.write("%2.2X%2.2X " % (da[i*2], da[i*2+1]))
ofile.write('\n')
# read in as a string
lenword = fid.readline()
l = int(lenword, 16)
print l
data = ""
for i in range((l+1)/2 ):
dw = fid.readline()
data += chr(int(dw[:2], 16))
data += chr(int(dw[2:], 16))
if l % 2 == 1:
data = data[:-1]
crc = frame.generateFCS(data)
totaldata = data + crc
# write valid packet
fid = file(filename + ".crc", 'w')
fid.write("%4.4X\n" % len(totaldata))
outdata = totaldata + '\x00'
for i in range(len(totaldata) / 2):
fid.write("%2.2X%2.2X\n" % (ord(outdata[2*i]), ord(outdata[2*i+1])))
# write corrupt packet
fid = file(filename + ".crcerror", 'w')
fid.write("%4.4X\n" % len(totaldata))
def packageData(data):
""" Takes in a data string and appends the CRC to it
"""
crc = frame.generateFCS(data)
return data + crc
bytestr = l[6:53]
octetsraw = bytestr.split(' ')
octets = [x for x in octetsraw if x != '']
alloctets += octets
l = fid.readline()
updateIPHeader(alloctets)
# add on the crc, but only if it's a req, not a resp
if "req" in outfilename:
# generate string
framestr = "".join([chr(int(x, 16)) for x in alloctets])
crcstr = frame.generateFCS(framestr)
alloctets.append("%2.2X" % ord(crcstr[0]))
alloctets.append("%2.2X" % ord(crcstr[1]))
alloctets.append("%2.2X" % ord(crcstr[2]))
alloctets.append("%2.2X" % ord(crcstr[3]))
framelen = len(alloctets)
ofid.write("%4.4X\n" % (int(framelen)))
for i in range(framelen/2):
ofid.write(alloctets[i*2] + alloctets[i*2+1] + '\n' )
if framelen % 2 == 1:
ofid.write(alloctets[-1] + '00' + '\n')
