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import time, types
from TftpShared import *
from TftpPacketFactory import *
from TftpStates import TftpContextClientDownload
class TftpClient(TftpSession):
"""This class is an implementation of a tftp client. Once instantiated, a
download can be initiated via the download() method."""
def __init__(self, host, port, options={}):
"""This constructor returns an instance of TftpClient, taking the
remote host, the remote port, and the filename to fetch."""
TftpSession.__init__(self)
self.context = None
self.host = host
self.iport = port
self.filename = None
self.options = options
# FIXME: If the blksize is DEF_BLKSIZE, we should just skip sending
# it.
if self.options.has_key('blksize'):
size = self.options['blksize']
tftpassert(types.IntType == type(size), "blksize must be an int")
if size < MIN_BLKSIZE or size > MAX_BLKSIZE:
raise TftpException, "Invalid blksize: %d" % size
else:
self.options['blksize'] = DEF_BLKSIZE
# Support other options here? timeout time, retries, etc?
# The remote sending port, to identify the connection.
self.port = None
self.sock = None
def gethost(self):
"Simple getter method for use in a property."
return self.__host
def sethost(self, host):
"""Setter method that also sets the address property as a result
of the host that is set."""
self.__host = host
self.address = socket.gethostbyname(host)
host = property(gethost, sethost)
def download(self, filename, output, packethook=None, timeout=SOCK_TIMEOUT):
"""This method initiates a tftp download from the configured remote
host, requesting the filename passed. It saves the file to a local
file specified in the output parameter. If a packethook is provided,
it must be a function that takes a single parameter, which will be a
copy of each DAT packet received in the form of a TftpPacketDAT
object. The timeout parameter may be used to override the default
SOCK_TIMEOUT setting, which is the amount of time that the client will
wait for a receive packet to arrive."""
# We're downloading.
self.context = TftpContextClientDownload(self.host,
self.iport,
filename,
output,
self.options,
packethook,
timeout)
self.context.start()
# Download happens here
self.context.end()
metrics = self.context.metrics
# FIXME: Should we output this? Shouldn't we let the client control
# output? This should be in the sample client, but not in the download
# call.
if metrics.duration == 0:
logger.info("Duration too short, rate undetermined")
else:
logger.info('')
logger.info("Downloaded %.2f bytes in %.2f seconds" % (metrics.bytes, metrics.duration))
logger.info("Average rate: %.2f kbps" % metrics.kbps)
logger.info("Received %d duplicate packets" % metrics.dupcount)
def upload(self, filename, input, packethook=None, timeout=SOCK_TIMEOUT):
# Open the input file.
self.fileobj = open(input, "rb")
recvpkt = None
curblock = 0
start_time = time.time()
self.bytes = 0
tftp_factory = TftpPacketFactory()
self.sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
self.sock.settimeout(timeout)
self.filename = filename
self.send_wrq()
self.state.state = 'wrq'
timeouts = 0
while True:
try:
(buffer, (raddress, rport)) = self.sock.recvfrom(MAX_BLKSIZE)
except socket.timeout, err:
timeouts += 1
if timeouts >= TIMEOUT_RETRIES:
raise TftpException, "Hit max timeouts, giving up."
else:
if self.state.state == 'dat' or self.state.state == 'fin':
logger.debug("Timing out on DAT. Need to resend.")
self.send_dat(packethook,resend=True)
elif self.state.state == 'wrq':
logger.debug("Timing out on WRQ.")
self.send_wrq(resend=True)
else:
tftpassert(False,
"Timing out in unsupported state %s" %
self.state.state)
continue
recvpkt = tftp_factory.parse(buffer)
logger.debug("Received %d bytes from %s:%s"
% (len(buffer), raddress, rport))
# Check for known "connection".
if raddress != self.address:
logger.warn("Received traffic from %s, expected host %s. Discarding"
% (raddress, self.host))
continue
if self.port and self.port != rport:
logger.warn("Received traffic from %s:%s but we're "
"connected to %s:%s. Discarding."
% (raddress, rport,
self.host, self.port))
continue
if not self.port and self.state.state == 'wrq':
self.port = rport
logger.debug("Set remote port for session to %s" % rport)
# Next packet type
if isinstance(recvpkt, TftpPacketACK):
logger.debug("Received an ACK from the server.")
# tftp on wrt54gl seems to answer with an ack to a wrq regardless
# if we sent options.
if recvpkt.blocknumber == 0 and self.state.state in ('oack','wrq'):
logger.debug("Received ACK with 0 blocknumber, starting upload")
self.state.state = 'dat'
self.send_dat(packethook)
else:
if self.state.state == 'dat' or self.state.state == 'fin':
if self.blocknumber == recvpkt.blocknumber:
logger.info("Received ACK for block %d"
% recvpkt.blocknumber)
if self.state.state == 'fin':
break
else:
self.send_dat(packethook)
elif recvpkt.blocknumber < self.blocknumber:
# Don't resend a DAT due to an old ACK. Fixes the
# sorceror's apprentice problem.
logger.warn("Received old ACK for block number %d"
% recvpkt.blocknumber)
else:
logger.warn("Received ACK for block number "
"%d, apparently from the future"
% recvpkt.blocknumber)
else:
logger.error("Received ACK with block number %d "
"while in state %s"
% (recvpkt.blocknumber,
self.state.state))
# Check other packet types.
elif isinstance(recvpkt, TftpPacketOACK):
if not self.state.state == 'wrq':
self.errors += 1
logger.error("Received OACK in state %s" % self.state.state)
continue
self.state.state = 'oack'
logger.info("Received OACK from server.")
if recvpkt.options.keys() > 0:
if recvpkt.match_options(self.options):
logger.info("Successful negotiation of options")
for key in self.options:
logger.info(" %s = %s" % (key, self.options[key]))
logger.debug("sending ACK to OACK")
ackpkt = TftpPacketACK()
ackpkt.blocknumber = 0
self.sock.sendto(ackpkt.encode().buffer, (self.host, self.port))
self.state.state = 'dat'
self.send_dat(packethook)
else:
logger.error("failed to negotiate options")
self.senderror(self.sock, TftpErrors.FailedNegotiation, self.host, self.port)
self.state.state = 'err'
raise TftpException, "Failed to negotiate options"
elif isinstance(recvpkt, TftpPacketERR):
self.state.state = 'err'
self.senderror(self.sock, TftpErrors.IllegalTftpOp, self.host, self.port)
tftpassert(False, "Received ERR from server: " + str(recvpkt))
elif isinstance(recvpkt, TftpPacketWRQ):
self.state.state = 'err'
self.senderror(self.sock, TftpErrors.IllegalTftpOp, self.host, self.port)
tftpassert(False, "Received WRQ from server: " + str(recvpkt))
else:
self.state.state = 'err'
self.senderror(self.sock, TftpErrors.IllegalTftpOp, self.host, self.port)
tftpassert(False, "Received unknown packet type from server: "
+ str(recvpkt))
# end while
self.fileobj.close()
end_time = time.time()
duration = end_time - start_time
if duration == 0:
logger.info("Duration too short, rate undetermined")
else:
logger.info('')
logger.info("Uploaded %d bytes in %d seconds" % (self.bytes, duration))
bps = (self.bytes * 8.0) / duration
kbps = bps / 1024.0
logger.info("Average rate: %.2f kbps" % kbps)
def send_dat(self, packethook, resend=False):
"""This method reads and sends a DAT packet based on what is in self.buffer."""
if not resend:
blksize = int(self.options['blksize'])
self.buffer = self.fileobj.read(blksize)
logger.debug("Read %d bytes into buffer" % len(self.buffer))
if len(self.buffer) < blksize:
logger.info("Reached EOF on file %s" % self.filename)
self.state.state = 'fin'
self.blocknumber += 1
if self.blocknumber > 65535:
logger.debug("Blocknumber rolled over to zero")
self.blocknumber = 0
self.bytes += len(self.buffer)
else:
logger.warn("Resending block number %d" % self.blocknumber)
dat = TftpPacketDAT()
dat.data = self.buffer
dat.blocknumber = self.blocknumber
logger.debug("Sending DAT packet %d" % self.blocknumber)
self.sock.sendto(dat.encode().buffer, (self.host, self.port))
self.timesent = time.time()
if packethook:
packethook(dat)
def send_wrq(self, resend=False):
"""This method sends a wrq"""
logger.info("Sending tftp upload request to %s" % self.host)
logger.info(" filename -> %s" % self.filename)
wrq = TftpPacketWRQ()
wrq.filename = self.filename
wrq.mode = "octet" # FIXME - shouldn't hardcode this
wrq.options = self.options
self.sock.sendto(wrq.encode().buffer, (self.host, self.iport))
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