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 msg[RSP]['_krpc_sender'] = addr
325 df.callback(msg[RSP])
327 # no tid, this transaction timed out already...
329 log.msg('timeout: %r' % msg[RSP]['id'])
330 elif msg[TYP] == ERR:
331 # Errors get processed by their TID's deferred's errback
332 if self.tids.has_key(msg[TID]):
333 df = self.tids[msg[TID]]
334 del(self.tids[msg[TID]])
336 df.errback(KrpcError(*msg[ERR]))
338 # day late and dollar short, just log it
339 log.msg("Got an error for an unknown request: %r" % (msg[ERR], ))
342 # Received an unknown message type
344 log.msg("unknown message type: %r" % msg)
345 if msg[TID] in self.tids:
346 df = self.tids[msg[TID]]
347 del(self.tids[msg[TID]])
349 df.errback(KrpcError(KRPC_ERROR_RECEIVED_UNKNOWN,
350 "Received an unknown message type: %r" % msg[TYP]))
352 def _sendResponse(self, request, addr, tid, msgType, response):
353 """Helper function for sending responses to nodes.
355 @param request: the name of the requested method
356 @type addr: (C{string}, C{int})
357 @param addr: source IP address and port of datagram.
358 @param tid: the transaction ID of the request
359 @param msgType: the type of message to respond with
360 @param response: the arguments for the response
366 # Create the response message
367 msg = {TID : tid, TYP : msgType, msgType : response}
370 log.msg("%d responding to %r: %s" % (self.factory.port, addr, msg))
374 # Make sure its not too long
375 if len(out) > UDP_PACKET_LIMIT:
376 # Can we remove some values to shorten it?
377 if 'values' in response:
378 # Save the original list of values
379 orig_values = response['values']
380 len_orig_values = len(bencode(orig_values))
382 # Caclulate the maximum value length possible
383 max_len_values = len_orig_values - (len(out) - UDP_PACKET_LIMIT)
384 assert max_len_values > 0
386 # Start with a calculation of how many values should be included
387 # (assumes all values are the same length)
388 per_value = (float(len_orig_values) - 2.0) / float(len(orig_values))
389 num_values = len(orig_values) - int(ceil(float(len(out) - UDP_PACKET_LIMIT) / per_value))
391 # Do a linear search for the actual maximum number possible
392 bencoded_values = len(bencode(orig_values[:num_values]))
393 while bencoded_values < max_len_values and num_values + 1 < len(orig_values):
394 bencoded_values += len(bencode(orig_values[num_values]))
396 while bencoded_values > max_len_values and num_values > 0:
398 bencoded_values -= len(bencode(orig_values[num_values]))
399 assert num_values > 0
402 response['values'] = orig_values[:num_values]
404 assert len(out) < UDP_PACKET_LIMIT
405 log.msg('Shortened a long packet from %d to %d values, new packet length: %d' %
406 (len(orig_values), num_values, len(out)))
408 # Too long a response, send an error
409 log.msg('Could not send response, too long: %d bytes' % len(out))
410 self.stats.errorAction(request)
411 msg = {TID : tid, TYP : ERR, ERR : [KRPC_ERROR_RESPONSE_TOO_LONG, "response was %d bytes" % len(out)]}
415 # Unknown error, send an error message
416 self.stats.errorAction(request)
417 msg = {TID : tid, TYP : ERR, ERR : [KRPC_ERROR_SERVER_ERROR, "unknown error sending response: %s" % str(e)]}
420 self.stats.sentBytes(len(out))
421 self.transport.write(out, addr)
424 def sendRequest(self, method, args):
425 """Send a request to the remote node.
427 @type method: C{string}
428 @param method: the methiod name to call on the remote node
429 @param args: the arguments to send to the remote node's method
432 raise KrpcError, (KRPC_ERROR_PROTOCOL_STOPPED, "cannot send, connection has been stopped")
434 # Create the request message
435 msg = {TID : newID(), TYP : REQ, REQ : method, ARG : args}
437 log.msg("%d sending to %r: %s" % (self.factory.port, self.addr, msg))
440 # Create the deferred and save it with the TID
442 self.tids[msg[TID]] = d
444 # Save the conclusion of the action
445 d.addCallbacks(self.stats.responseAction, self.stats.failedAction,
446 callbackArgs = (method, ), errbackArgs = (method, ))
448 # Schedule a later timeout call
449 def timeOut(tids = self.tids, id = msg[TID], method = method, addr = self.addr):
450 """Call the deferred's errback if a timeout occurs."""
454 df.errback(KrpcError(KRPC_ERROR_TIMEOUT, "timeout waiting for '%s' from %r" % (method, addr)))
455 later = reactor.callLater(KRPC_TIMEOUT, timeOut)
457 # Cancel the timeout call if a response is received
458 def dropTimeOut(dict, later_call = later):
459 """Cancel the timeout call when a response is received."""
460 if later_call.active():
463 d.addBoth(dropTimeOut)
466 self.stats.sentAction(method)
467 self.stats.sentBytes(len(data))
469 self.transport.write(data, self.addr)
473 """Timeout all pending requests."""
474 for df in self.tids.values():
475 df.errback(KrpcError(KRPC_ERROR_PROTOCOL_STOPPED,
476 'connection has been stopped while waiting for response'))
480 #{ For testing the KRPC protocol
481 def connectionForAddr(host, port):
484 class Receiver(protocol.Factory):
488 def krpc_store(self, msg, _krpc_sender):
491 def krpc_echo(self, msg, _krpc_sender):
493 def krpc_values(self, length, num, _krpc_sender):
494 return {'values': ['1'*length]*num}
497 from stats import StatsLogger
499 a = hostbroker(af, StatsLogger(None, None, {}), {'SPEW': False})
501 p = reactor.listenUDP(port, a)
504 class KRPCTests(unittest.TestCase):
508 self.af, self.a, self.ap = make(1180)
509 self.bf, self.b, self.bp = make(1181)
512 self.ap.stopListening()
513 self.bp.stopListening()
515 def bufEquals(self, result, value):
516 self.failUnlessEqual(self.bf.buf, value)
518 def testSimpleMessage(self):
519 d = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('store', {'msg' : "This is a test."})
520 d.addCallback(self.bufEquals, ["This is a test."])
523 def testMessageBlast(self):
525 d = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('store', {'msg' : "This is a test."})
526 d.addCallback(self.bufEquals, ["This is a test."] * 100)
530 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is a test."})
531 df.addCallback(self.gotMsg, "This is a test.")
534 def gotMsg(self, dict, should_be):
535 _krpc_sender = dict['_krpc_sender']
536 self.failUnlessEqual(dict['msg'], should_be)
538 def testManyEcho(self):
539 for i in xrange(100):
540 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is a test."})
541 df.addCallback(self.gotMsg, "This is a test.")
544 def testMultiEcho(self):
545 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is a test."})
546 df.addCallback(self.gotMsg, "This is a test.")
548 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is another test."})
549 df.addCallback(self.gotMsg, "This is another test.")
551 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is yet another test."})
552 df.addCallback(self.gotMsg, "This is yet another test.")
556 def testEchoReset(self):
557 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is a test."})
558 df.addCallback(self.gotMsg, "This is a test.")
560 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is another test."})
561 df.addCallback(self.gotMsg, "This is another test.")
562 df.addCallback(self.echoReset)
565 def echoReset(self, dict):
566 del(self.a.connections[('127.0.0.1', 1181)])
567 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is yet another test."})
568 df.addCallback(self.gotMsg, "This is yet another test.")
571 def testUnknownMeth(self):
572 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('blahblah', {'msg' : "This is a test."})
573 df = self.failUnlessFailure(df, KrpcError)
574 df.addBoth(self.gotErr, KRPC_ERROR_METHOD_UNKNOWN)
577 def testMalformedRequest(self):
578 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('echo', {'msg' : "This is a test.", 'foo': 'bar'})
579 df = self.failUnlessFailure(df, KrpcError)
580 df.addBoth(self.gotErr, KRPC_ERROR_MALFORMED_REQUEST, TypeError)
583 def gotErr(self, value, should_be, *errorTypes):
584 self.failUnlessEqual(value[0], should_be)
586 self.flushLoggedErrors(*errorTypes)
588 def testLongPackets(self):
589 df = self.a.connectionForAddr(('127.0.0.1', 1181)).sendRequest('values', {'length' : 1, 'num': 2000})
590 df.addCallback(self.gotLongRsp)
593 def gotLongRsp(self, dict):
594 # Not quite accurate, but good enough
595 self.failUnless(len(bencode(dict))-10 < UDP_PACKET_LIMIT)