1 ## Copyright 2002-2003 Andrew Loewenstern, All Rights Reserved
2 # see LICENSE.txt for license information
4 """The KRPC communication protocol implementation.
6 @var KRPC_TIMEOUT: the number of seconds after which requests timeout
7 @var UDP_PACKET_LIMIT: the maximum number of bytes that can be sent in a
8 UDP packet without fragmentation
10 @var KRPC_ERROR: the code for a generic error
11 @var KRPC_ERROR_SERVER_ERROR: the code for a server error
12 @var KRPC_ERROR_MALFORMED_PACKET: the code for a malformed packet error
13 @var KRPC_ERROR_METHOD_UNKNOWN: the code for a method unknown error
14 @var KRPC_ERROR_MALFORMED_REQUEST: the code for a malformed request error
15 @var KRPC_ERROR_INVALID_TOKEN: the code for an invalid token error
16 @var KRPC_ERROR_RESPONSE_TOO_LONG: the code for a response too long error
18 @var KRPC_ERROR_INTERNAL: the code for an internal error
19 @var KRPC_ERROR_RECEIVED_UNKNOWN: the code for an unknown message type error
20 @var KRPC_ERROR_TIMEOUT: the code for a timeout error
21 @var KRPC_ERROR_PROTOCOL_STOPPED: the code for a stopped protocol error
23 @var TID: the identifier for the transaction ID
24 @var REQ: the identifier for a request packet
25 @var RSP: the identifier for a response packet
26 @var TYP: the identifier for the type of packet
27 @var ARG: the identifier for the argument to the request
28 @var ERR: the identifier for an error packet
30 @group Remote node error codes: KRPC_ERROR, KRPC_ERROR_SERVER_ERROR,
31 KRPC_ERROR_MALFORMED_PACKET, KRPC_ERROR_METHOD_UNKNOWN,
32 KRPC_ERROR_MALFORMED_REQUEST, KRPC_ERROR_INVALID_TOKEN,
33 KRPC_ERROR_RESPONSE_TOO_LONG
34 @group Local node error codes: KRPC_ERROR_INTERNAL, KRPC_ERROR_RECEIVED_UNKNOWN,
35 KRPC_ERROR_TIMEOUT, KRPC_ERROR_PROTOCOL_STOPPED
36 @group Command identifiers: TID, REQ, RSP, TYP, ARG, ERR
40 from bencode import bencode, bdecode
41 from time import asctime
44 from twisted.internet.defer import Deferred
45 from twisted.internet import protocol, reactor
46 from twisted.python import log
47 from twisted.trial import unittest
49 from khash import newID
52 UDP_PACKET_LIMIT = 1472
56 KRPC_ERROR_SERVER_ERROR = 201
57 KRPC_ERROR_MALFORMED_PACKET = 202
58 KRPC_ERROR_METHOD_UNKNOWN = 203
59 KRPC_ERROR_MALFORMED_REQUEST = 204
60 KRPC_ERROR_INVALID_TOKEN = 205
61 KRPC_ERROR_RESPONSE_TOO_LONG = 206
64 KRPC_ERROR_INTERNAL = 100
65 KRPC_ERROR_RECEIVED_UNKNOWN = 101
66 KRPC_ERROR_TIMEOUT = 102
67 KRPC_ERROR_PROTOCOL_STOPPED = 103
77 class KrpcError(Exception):
78 """An error occurred in the KRPC protocol."""
81 def verifyMessage(msg):
82 """Check received message for corruption and errors.
84 @type msg: C{dictionary}
85 @param msg: the dictionary of information received on the connection
86 @raise KrpcError: if the message is corrupt
90 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "not a dictionary")
92 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "no message type")
95 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "request type not specified")
96 if type(msg[REQ]) != str:
97 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "request type is not a string")
99 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "no arguments for request")
100 if type(msg[ARG]) != dict:
101 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "arguments for request are not in a dictionary")
102 elif msg[TYP] == RSP:
104 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "response not specified")
105 if type(msg[RSP]) != dict:
106 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "response is not a dictionary")
107 elif msg[TYP] == ERR:
109 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "error not specified")
110 if type(msg[ERR]) != list:
111 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "error is not a list")
112 if len(msg[ERR]) != 2:
113 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "error is not a 2-element list")
114 if type(msg[ERR][0]) not in (int, long):
115 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "error number is not a number")
116 if type(msg[ERR][1]) != str:
117 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "error string is not a string")
119 # raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "unknown message type")
121 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "no transaction ID specified")
122 if type(msg[TID]) != str:
123 raise KrpcError, (KRPC_ERROR_MALFORMED_PACKET, "transaction id is not a string")
125 class hostbroker(protocol.DatagramProtocol):
126 """The factory for the KRPC protocol.
128 @type server: L{khashmir.Khashmir}
129 @ivar server: the main Khashmir program
130 @type stats: L{stats.StatsLogger}
131 @ivar stats: the statistics logger to save transport info
132 @type config: C{dictionary}
133 @ivar config: the configuration parameters for the DHT
134 @type connections: C{dictionary}
135 @ivar connections: all the connections that have ever been made to the
136 protocol, keys are IP address and port pairs, values are L{KRPC}
137 protocols for the addresses
138 @ivar protocol: the protocol to use to handle incoming connections
140 @type addr: (C{string}, C{int})
141 @ivar addr: the IP address and port of this node
144 def __init__(self, server, stats, config):
145 """Initialize the factory.
147 @type server: L{khashmir.Khashmir}
148 @param server: the main DHT program
149 @type stats: L{stats.StatsLogger}
150 @param stats: the statistics logger to save transport info
151 @type config: C{dictionary}
152 @param config: the configuration parameters for the DHT
157 # this should be changed to storage that drops old entries
158 self.connections = {}
160 def datagramReceived(self, datagram, addr):
161 """Optionally create a new protocol object, and handle the new datagram.
163 @type datagram: C{string}
164 @param datagram: the data received from the transport.
165 @type addr: (C{string}, C{int})
166 @param addr: source IP address and port of datagram.
168 c = self.connectionForAddr(addr)
169 c.datagramReceived(datagram, addr)
171 # del self.connections[addr]
173 def connectionForAddr(self, addr):
174 """Get a protocol object for the source.
176 @type addr: (C{string}, C{int})
177 @param addr: source IP address and port of datagram.
179 # Don't connect to ourself
180 if addr == self.addr:
183 # Create a new protocol object if necessary
184 if not self.connections.has_key(addr):
185 conn = self.protocol(addr, self.server, self.stats, self.transport, self.config['SPEW'])
186 self.connections[addr] = conn
188 conn = self.connections[addr]
191 def makeConnection(self, transport):
192 """Make a connection to a transport and save our address."""
193 protocol.DatagramProtocol.makeConnection(self, transport)
194 tup = transport.getHost()
195 self.addr = (tup.host, tup.port)
197 def stopProtocol(self):
198 """Stop all the open connections."""
199 for conn in self.connections.values():
201 protocol.DatagramProtocol.stopProtocol(self)
204 """The KRPC protocol implementation.
206 @ivar transport: the transport to use for the protocol
207 @type factory: L{khashmir.Khashmir}
208 @ivar factory: the main Khashmir program
209 @type stats: L{stats.StatsLogger}
210 @ivar stats: the statistics logger to save transport info
211 @type addr: (C{string}, C{int})
212 @ivar addr: the IP address and port of the source node
213 @type noisy: C{boolean}
214 @ivar noisy: whether to log additional details of the protocol
215 @type tids: C{dictionary}
216 @ivar tids: the transaction IDs outstanding for requests, keys are the
217 transaction ID of the request, values are the deferreds to call with
219 @type stopped: C{boolean}
220 @ivar stopped: whether the protocol has been stopped
223 def __init__(self, addr, server, stats, transport, spew = False):
224 """Initialize the protocol.
226 @type addr: (C{string}, C{int})
227 @param addr: the IP address and port of the source node
228 @type server: L{khashmir.Khashmir}
229 @param server: the main Khashmir program
230 @type stats: L{stats.StatsLogger}
231 @param stats: the statistics logger to save transport info
232 @param transport: the transport to use for the protocol
233 @type spew: C{boolean}
234 @param spew: whether to log additional details of the protocol
235 (optional, defaults to False)
237 self.transport = transport
238 self.factory = server
245 def datagramReceived(self, data, addr):
246 """Process the new datagram.
248 @type data: C{string}
249 @param data: the data received from the transport.
250 @type addr: (C{string}, C{int})
251 @param addr: source IP address and port of datagram.
253 self.stats.receivedBytes(len(data))
256 log.msg("stopped, dropping message from %r: %s" % (addr, data))
258 # Bdecode the message
263 log.msg("krpc bdecode error: ")
267 # Make sure the remote node isn't trying anything funny
271 log.msg("krpc message verification error: ")
276 log.msg("%d received from %r: %s" % (self.factory.port, addr, msg))
278 # Process it based on its type
282 # Requests are handled by the factory
283 f = getattr(self.factory ,"krpc_" + msg[REQ], None)
284 msg[ARG]['_krpc_sender'] = self.addr
285 if f and callable(f):
286 self.stats.receivedAction(msg[REQ])
288 ret = f(*(), **msg[ARG])
290 log.msg('Got a Krpc error while running: krpc_%s' % msg[REQ])
292 self.stats.errorAction(msg[REQ])
293 olen = self._sendResponse(msg[REQ], addr, msg[TID], ERR,
296 log.msg('Got a malformed request for: krpc_%s' % msg[REQ])
298 self.stats.errorAction(msg[REQ])
299 olen = self._sendResponse(msg[REQ], addr, msg[TID], ERR,
300 [KRPC_ERROR_MALFORMED_REQUEST, str(e)])
302 log.msg('Got an unknown error while running: krpc_%s' % msg[REQ])
304 self.stats.errorAction(msg[REQ])
305 olen = self._sendResponse(msg[REQ], addr, msg[TID], ERR,
306 [KRPC_ERROR_SERVER_ERROR, str(e)])
308 olen = self._sendResponse(msg[REQ], addr, msg[TID], RSP, ret)
310 # Request for unknown method
311 log.msg("ERROR: don't know about method %s" % msg[REQ])
312 self.stats.receivedAction('unknown')
313 olen = self._sendResponse(msg[REQ], addr, msg[TID], ERR,
314 [KRPC_ERROR_METHOD_UNKNOWN, "unknown method "+str(msg[REQ])])
316 log.msg("%s >>> %s - %s %s %s" % (addr, self.factory.node.port,
317 ilen, msg[REQ], olen))
318 elif msg[TYP] == RSP:
319 # Responses get processed by their TID's deferred
320 if self.tids.has_key(msg[TID]):
321 df = self.tids[msg[TID]]
323 del(self.tids[msg[TID]])
324 df.callback({'rsp' : msg[RSP], '_krpc_sender': addr})
326 # no tid, this transaction timed out already...
328 log.msg('timeout: %r' % msg[RSP]['id'])
329 elif msg[TYP] == ERR:
330 # Errors get processed by their TID's deferred's errback
331 if self.tids.has_key(msg[TID]):
332 df = self.tids[msg[TID]]
333 del(self.tids[msg[TID]])
335 df.errback(KrpcError(*msg[ERR]))
337 # day late and dollar short, just log it
338 log.msg("Got an error for an unknown request: %r" % (msg[ERR], ))
341 # Received an unknown message type
343 log.msg("unknown message type: %r" % msg)
344 if msg[TID] in self.tids:
345 df = self.tids[msg[TID]]
346 del(self.tids[msg[TID]])
348 df.errback(KrpcError(KRPC_ERROR_RECEIVED_UNKNOWN,
349 "Received an unknown message type: %r" % msg[TYP]))
351 def _sendResponse(self, request, addr, tid, msgType, response):
352 """Helper function for sending responses to nodes.
354 @param request: the name of the requested method
355 @type addr: (C{string}, C{int})
356 @param addr: source IP address and port of datagram.
357 @param tid: the transaction ID of the request
358 @param msgType: the type of message to respond with
359 @param response: the arguments for the response
365 # Create the response message
366 msg = {TID : tid, TYP : msgType, msgType : response}
369 log.msg("%d responding to %r: %s" % (self.factory.port, addr, msg))
373 # Make sure its not too long
374 if len(out) > UDP_PACKET_LIMIT:
375 # Can we remove some values to shorten it?
376 if 'values' in response:
377 # Save the original list of values
378 orig_values = response['values']
379 len_orig_values = len(bencode(orig_values))
381 # Caclulate the maximum value length possible
382 max_len_values = len_orig_values - (len(out) - UDP_PACKET_LIMIT)
383 assert max_len_values > 0
385 # Start with a calculation of how many values should be included
386 # (assumes all values are the same length)
387 per_value = (float(len_orig_values) - 2.0) / float(len(orig_values))
388 num_values = len(orig_values) - int(ceil(float(len(out) - UDP_PACKET_LIMIT) / per_value))
390 # Do a linear search for the actual maximum number possible
391 bencoded_values = len(bencode(orig_values[:num_values]))
392 while bencoded_values < max_len_values and num_values + 1 < len(orig_values):
393 bencoded_values += len(bencode(orig_values[num_values]))
395 while bencoded_values > max_len_values and num_values > 0:
397 bencoded_values -= len(bencode(orig_values[num_values]))
398 assert num_values > 0
401 response['values'] = orig_values[:num_values]
403 assert len(out) < UDP_PACKET_LIMIT
404 log.msg('Shortened a long packet from %d to %d values, new packet length: %d' %
405 (len(orig_values), num_values, len(out)))
407 # Too long a response, send an error
408 log.msg('Could not send response, too long: %d bytes' % len(out))
409 self.stats.errorAction(request)
410 msg = {TID : tid, TYP : ERR, ERR : [KRPC_ERROR_RESPONSE_TOO_LONG, "response was %d bytes" % len(out)]}
414 # Unknown error, send an error message
415 self.stats.errorAction(request)
416 msg = {TID : tid, TYP : ERR, ERR : [KRPC_ERROR_SERVER_ERROR, "unknown error sending response: %s" % str(e)]}
419 self.stats.sentBytes(len(out))
420 self.transport.write(out, addr)
423 def sendRequest(self, method, args):
424 """Send a request to the remote node.
426 @type method: C{string}
427 @param method: the methiod name to call on the remote node
428 @param args: the arguments to send to the remote node's method
431 raise KrpcError, (KRPC_ERROR_PROTOCOL_STOPPED, "cannot send, connection has been stopped")
433 # Create the request message
434 msg = {TID : newID(), TYP : REQ, REQ : method, ARG : args}
436 log.msg("%d sending to %r: %s" % (self.factory.port, self.addr, msg))
439 # Create the deferred and save it with the TID
441 self.tids[msg[TID]] = d
443 # Save the conclusion of the action
444 d.addCallbacks(self.stats.responseAction, self.stats.failedAction,
445 callbackArgs = (method, ), errbackArgs = (method, ))
447 # Schedule a later timeout call
448 def timeOut(tids = self.tids, id = msg[TID], method = method, addr = self.addr):
449 """Call the deferred's errback if a timeout occurs."""
453 df.errback(KrpcError(KRPC_ERROR_TIMEOUT, "timeout waiting for '%s' from %r" % (method, addr)))
454 later = reactor.callLater(KRPC_TIMEOUT, timeOut)
456 # Cancel the timeout call if a response is received
457 def dropTimeOut(dict, later_call = later):
458 """Cancel the timeout call when a response is received."""
459 if later_call.active():
462 d.addBoth(dropTimeOut)
465 self.stats.sentAction(method)
466 self.stats.sentBytes(len(data))
468 self.transport.write(data, self.addr)
472 """Timeout all pending requests."""
473 for df in self.tids.values():
474 df.errback(KrpcError(KRPC_ERROR_PROTOCOL_STOPPED,
475 'connection has been stopped while waiting for response'))
479 #{ For testing the KRPC protocol
480 def connectionForAddr(host, port):
483 class Receiver(protocol.Factory):
487 def krpc_store(self, msg, _krpc_sender):
490 def krpc_echo(self, msg, _krpc_sender):
492 def krpc_values(self, length, num, _krpc_sender):
493 return {'values': ['1'*length]*num}
497 a = hostbroker(af, {'SPEW': False})
499 p = reactor.listenUDP(port, a)
502 class KRPCTests(unittest.TestCase):
506 self.af, self.a, self.ap = make(1180)
507 self.bf, self.b, self.bp = make(1181)
510 self.ap.stopListening()
511 self.bp.stopListening()
513 def bufEquals(self, result, value):
514 self.failUnlessEqual(self.bf.buf, value)
516 def testSimpleMessage(self):
517 d = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('store', {'msg' : "This is a test."})
518 d.addCallback(self.bufEquals, ["This is a test."])
521 def testMessageBlast(self):
523 d = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('store', {'msg' : "This is a test."})
524 d.addCallback(self.bufEquals, ["This is a test."] * 100)
528 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is a test."})
529 df.addCallback(self.gotMsg, "This is a test.")
532 def gotMsg(self, dict, should_be):
533 _krpc_sender = dict['_krpc_sender']
535 self.failUnlessEqual(msg['msg'], should_be)
537 def testManyEcho(self):
538 for i in xrange(100):
539 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is a test."})
540 df.addCallback(self.gotMsg, "This is a test.")
543 def testMultiEcho(self):
544 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is a test."})
545 df.addCallback(self.gotMsg, "This is a test.")
547 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is another test."})
548 df.addCallback(self.gotMsg, "This is another test.")
550 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is yet another test."})
551 df.addCallback(self.gotMsg, "This is yet another test.")
555 def testEchoReset(self):
556 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is a test."})
557 df.addCallback(self.gotMsg, "This is a test.")
559 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is another test."})
560 df.addCallback(self.gotMsg, "This is another test.")
561 df.addCallback(self.echoReset)
564 def echoReset(self, dict):
565 del(self.a.connections[('127.0.0.1', 1181)])
566 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is yet another test."})
567 df.addCallback(self.gotMsg, "This is yet another test.")
570 def testUnknownMeth(self):
571 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('blahblah', {'msg' : "This is a test."})
572 df.addBoth(self.gotErr, KRPC_ERROR_METHOD_UNKNOWN)
575 def testMalformedRequest(self):
576 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is a test.", 'foo': 'bar'})
577 df.addBoth(self.gotErr, KRPC_ERROR_MALFORMED_REQUEST)
580 def gotErr(self, err, should_be):
581 self.failUnlessEqual(err.value[0], should_be)
583 def testLongPackets(self):
584 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('values', {'length' : 1, 'num': 2000})
585 df.addCallback(self.gotLongRsp)
588 def gotLongRsp(self, dict):
589 # Not quite accurate, but good enough
590 self.failUnless(len(bencode(dict))-10 < UDP_PACKET_LIMIT)