4 # Copyright (C) 2007, 2008 Google Inc.
6 # This program is free software; you can redistribute it and/or modify
7 # it under the terms of the GNU General Public License as published by
8 # the Free Software Foundation; either version 2 of the License, or
9 # (at your option) any later version.
11 # This program is distributed in the hope that it will be useful, but
12 # WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 # General Public License for more details.
16 # You should have received a copy of the GNU General Public License
17 # along with this program; if not, write to the Free Software
18 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
32 from cStringIO import StringIO
34 from ganeti import constants
35 from ganeti import serializer
36 from ganeti import utils
39 HTTP_GANETI_VERSION = "Ganeti %s" % constants.RELEASE_VERSION
43 HTTP_NOT_MODIFIED = 304
53 HTTP_DELETE = "DELETE"
57 HTTP_SERVER = "Server"
59 HTTP_USER_AGENT = "User-Agent"
60 HTTP_CONTENT_TYPE = "Content-Type"
61 HTTP_CONTENT_LENGTH = "Content-Length"
62 HTTP_CONNECTION = "Connection"
63 HTTP_KEEP_ALIVE = "Keep-Alive"
64 HTTP_WWW_AUTHENTICATE = "WWW-Authenticate"
65 HTTP_AUTHORIZATION = "Authorization"
66 HTTP_AUTHENTICATION_INFO = "Authentication-Info"
69 _SSL_UNEXPECTED_EOF = "Unexpected EOF"
75 SOCKOP_HANDSHAKE) = range(4)
77 # send/receive quantum
81 class HttpError(Exception):
82 """Internal exception for HTTP errors.
84 This should only be used for internal error reporting.
89 class HttpConnectionClosed(Exception):
90 """Internal exception for a closed connection.
92 This should only be used for internal error reporting. Only use
93 it if there's no other way to report this condition.
98 class HttpSessionHandshakeUnexpectedEOF(HttpError):
99 """Internal exception for errors during SSL handshake.
101 This should only be used for internal error reporting.
106 class HttpSocketTimeout(Exception):
107 """Internal exception for socket timeouts.
109 This should only be used for internal error reporting.
114 class HttpException(Exception):
118 def __init__(self, message=None, headers=None):
119 Exception.__init__(self)
120 self.message = message
121 self.headers = headers
124 class HttpBadRequest(HttpException):
127 RFC2616, 10.4.1: The request could not be understood by the server
128 due to malformed syntax. The client SHOULD NOT repeat the request
129 without modifications.
135 class HttpUnauthorized(HttpException):
138 RFC2616, section 10.4.2: The request requires user
139 authentication. The response MUST include a WWW-Authenticate header
140 field (section 14.47) containing a challenge applicable to the
147 class HttpForbidden(HttpException):
150 RFC2616, 10.4.4: The server understood the request, but is refusing
151 to fulfill it. Authorization will not help and the request SHOULD
158 class HttpNotFound(HttpException):
161 RFC2616, 10.4.5: The server has not found anything matching the
162 Request-URI. No indication is given of whether the condition is
163 temporary or permanent.
169 class HttpMethodNotAllowed(HttpException):
170 """405 Method Not Allowed
172 RFC2616, 10.4.6: The method specified in the Request-Line is not
173 allowed for the resource identified by the Request-URI. The response
174 MUST include an Allow header containing a list of valid methods for
175 the requested resource.
181 class HttpRequestTimeout(HttpException):
182 """408 Request Timeout
184 RFC2616, 10.4.9: The client did not produce a request within the
185 time that the server was prepared to wait. The client MAY repeat the
186 request without modifications at any later time.
192 class HttpConflict(HttpException):
195 RFC2616, 10.4.10: The request could not be completed due to a
196 conflict with the current state of the resource. This code is only
197 allowed in situations where it is expected that the user might be
198 able to resolve the conflict and resubmit the request.
204 class HttpGone(HttpException):
207 RFC2616, 10.4.11: The requested resource is no longer available at
208 the server and no forwarding address is known. This condition is
209 expected to be considered permanent.
215 class HttpLengthRequired(HttpException):
216 """411 Length Required
218 RFC2616, 10.4.12: The server refuses to accept the request without a
219 defined Content-Length. The client MAY repeat the request if it adds
220 a valid Content-Length header field containing the length of the
221 message-body in the request message.
227 class HttpPreconditionFailed(HttpException):
228 """412 Precondition Failed
230 RFC2616, 10.4.13: The precondition given in one or more of the
231 request-header fields evaluated to false when it was tested on the
238 class HttpInternalServerError(HttpException):
239 """500 Internal Server Error
241 RFC2616, 10.5.1: The server encountered an unexpected condition
242 which prevented it from fulfilling the request.
248 class HttpNotImplemented(HttpException):
249 """501 Not Implemented
251 RFC2616, 10.5.2: The server does not support the functionality
252 required to fulfill the request.
258 class HttpBadGateway(HttpException):
261 RFC2616, 10.5.3: The server, while acting as a gateway or proxy,
262 received an invalid response from the upstream server it accessed in
263 attempting to fulfill the request.
269 class HttpServiceUnavailable(HttpException):
270 """503 Service Unavailable
272 RFC2616, 10.5.4: The server is currently unable to handle the
273 request due to a temporary overloading or maintenance of the server.
279 class HttpGatewayTimeout(HttpException):
280 """504 Gateway Timeout
282 RFC2616, 10.5.5: The server, while acting as a gateway or proxy, did
283 not receive a timely response from the upstream server specified by
284 the URI (e.g. HTTP, FTP, LDAP) or some other auxiliary server
285 (e.g. DNS) it needed to access in attempting to complete the
292 class HttpVersionNotSupported(HttpException):
293 """505 HTTP Version Not Supported
295 RFC2616, 10.5.6: The server does not support, or refuses to support,
296 the HTTP protocol version that was used in the request message.
302 class HttpJsonConverter:
303 CONTENT_TYPE = "application/json"
305 def Encode(self, data):
306 return serializer.DumpJson(data)
308 def Decode(self, data):
309 return serializer.LoadJson(data)
312 def WaitForSocketCondition(sock, event, timeout):
313 """Waits for a condition to occur on the socket.
316 @param sock: Wait for events on this socket
318 @param event: ORed condition (see select module)
319 @type timeout: float or None
320 @param timeout: Timeout in seconds
322 @return: None for timeout, otherwise occured conditions
325 check = (event | select.POLLPRI |
326 select.POLLNVAL | select.POLLHUP | select.POLLERR)
328 if timeout is not None:
329 # Poller object expects milliseconds
332 poller = select.poll()
333 poller.register(sock, event)
336 # TODO: If the main thread receives a signal and we have no timeout, we
337 # could wait forever. This should check a global "quit" flag or
338 # something every so often.
339 io_events = poller.poll(timeout)
343 for (evfd, evcond) in io_events:
347 poller.unregister(sock)
350 def SocketOperation(sock, op, arg1, timeout):
351 """Wrapper around socket functions.
353 This function abstracts error handling for socket operations, especially
354 for the complicated interaction with OpenSSL.
357 @param sock: Socket for the operation
359 @param op: Operation to execute (SOCKOP_* constants)
361 @param arg1: Parameter for function (if needed)
362 @type timeout: None or float
363 @param timeout: Timeout in seconds or None
364 @return: Return value of socket function
367 # TODO: event_poll/event_check/override
368 if op in (SOCKOP_SEND, SOCKOP_HANDSHAKE):
369 event_poll = select.POLLOUT
371 elif op == SOCKOP_RECV:
372 event_poll = select.POLLIN
374 elif op == SOCKOP_SHUTDOWN:
377 # The timeout is only used when OpenSSL requests polling for a condition.
378 # It is not advisable to have no timeout for shutdown.
382 raise AssertionError("Invalid socket operation")
384 # Handshake is only supported by SSL sockets
385 if (op == SOCKOP_HANDSHAKE and
386 not isinstance(sock, OpenSSL.SSL.ConnectionType)):
389 # No override by default
393 # Poll only for certain operations and when asked for by an override
394 if event_override or op in (SOCKOP_SEND, SOCKOP_RECV, SOCKOP_HANDSHAKE):
396 wait_for_event = event_override
398 wait_for_event = event_poll
400 event = WaitForSocketCondition(sock, wait_for_event, timeout)
402 raise HttpSocketTimeout()
404 if (op == SOCKOP_RECV and
405 event & (select.POLLNVAL | select.POLLHUP | select.POLLERR)):
408 if not event & wait_for_event:
416 if op == SOCKOP_SEND:
417 return sock.send(arg1)
419 elif op == SOCKOP_RECV:
420 return sock.recv(arg1)
422 elif op == SOCKOP_SHUTDOWN:
423 if isinstance(sock, OpenSSL.SSL.ConnectionType):
424 # PyOpenSSL's shutdown() doesn't take arguments
425 return sock.shutdown()
427 return sock.shutdown(arg1)
429 elif op == SOCKOP_HANDSHAKE:
430 return sock.do_handshake()
432 except OpenSSL.SSL.WantWriteError:
433 # OpenSSL wants to write, poll for POLLOUT
434 event_override = select.POLLOUT
437 except OpenSSL.SSL.WantReadError:
438 # OpenSSL wants to read, poll for POLLIN
439 event_override = select.POLLIN | select.POLLPRI
442 except OpenSSL.SSL.WantX509LookupError:
445 except OpenSSL.SSL.ZeroReturnError, err:
446 # SSL Connection has been closed. In SSL 3.0 and TLS 1.0, this only
447 # occurs if a closure alert has occurred in the protocol, i.e. the
448 # connection has been closed cleanly. Note that this does not
449 # necessarily mean that the transport layer (e.g. a socket) has been
451 if op == SOCKOP_SEND:
452 # Can happen during a renegotiation
453 raise HttpConnectionClosed(err.args)
454 elif op == SOCKOP_RECV:
457 # SSL_shutdown shouldn't return SSL_ERROR_ZERO_RETURN
458 raise socket.error(err.args)
460 except OpenSSL.SSL.SysCallError, err:
461 if op == SOCKOP_SEND:
462 # arg1 is the data when writing
463 if err.args and err.args[0] == -1 and arg1 == "":
464 # errors when writing empty strings are expected
468 if err.args == (-1, _SSL_UNEXPECTED_EOF):
469 if op == SOCKOP_RECV:
471 elif op == SOCKOP_HANDSHAKE:
472 # Can happen if peer disconnects directly after the connection is
474 raise HttpSessionHandshakeUnexpectedEOF(err.args)
476 raise socket.error(err.args)
478 except OpenSSL.SSL.Error, err:
479 raise socket.error(err.args)
481 except socket.error, err:
482 if err.args and err.args[0] == errno.EAGAIN:
489 def ShutdownConnection(sock, close_timeout, write_timeout, msgreader, force):
490 """Closes the connection.
493 @param sock: Socket to be shut down
494 @type close_timeout: float
495 @param close_timeout: How long to wait for the peer to close
497 @type write_timeout: float
498 @param write_timeout: Write timeout for shutdown
499 @type msgreader: http.HttpMessageReader
500 @param msgreader: Request message reader, used to determine whether
501 peer should close connection
503 @param force: Whether to forcibly close the connection without
507 #print msgreader.peer_will_close, force
508 if msgreader and msgreader.peer_will_close and not force:
509 # Wait for peer to close
511 # Check whether it's actually closed
512 if not SocketOperation(sock, SOCKOP_RECV, 1, close_timeout):
514 except (socket.error, HttpError, HttpSocketTimeout):
515 # Ignore errors at this stage
518 # Close the connection from our side
520 # We don't care about the return value, see NOTES in SSL_shutdown(3).
521 SocketOperation(sock, SOCKOP_SHUTDOWN, socket.SHUT_RDWR,
523 except HttpSocketTimeout:
524 raise HttpError("Timeout while shutting down connection")
525 except socket.error, err:
527 if not (err.args and err.args[0] == errno.ENOTCONN):
528 raise HttpError("Error while shutting down connection: %s" % err)
531 def Handshake(sock, write_timeout):
532 """Shakes peer's hands.
535 @param sock: Socket to be shut down
536 @type write_timeout: float
537 @param write_timeout: Write timeout for handshake
541 return SocketOperation(sock, SOCKOP_HANDSHAKE, None, write_timeout)
542 except HttpSocketTimeout:
543 raise HttpError("Timeout during SSL handshake")
544 except socket.error, err:
545 raise HttpError("Error in SSL handshake: %s" % err)
548 class HttpSslParams(object):
549 """Data class for SSL key and certificate.
552 def __init__(self, ssl_key_path, ssl_cert_path):
553 """Initializes this class.
555 @type ssl_key_path: string
556 @param ssl_key_path: Path to file containing SSL key in PEM format
557 @type ssl_cert_path: string
558 @param ssl_cert_path: Path to file containing SSL certificate
562 self.ssl_key_pem = utils.ReadFile(ssl_key_path)
563 self.ssl_cert_pem = utils.ReadFile(ssl_cert_path)
566 return OpenSSL.crypto.load_privatekey(OpenSSL.crypto.FILETYPE_PEM,
569 def GetCertificate(self):
570 return OpenSSL.crypto.load_certificate(OpenSSL.crypto.FILETYPE_PEM,
574 class HttpBase(object):
575 """Base class for HTTP server and client.
579 self.using_ssl = None
580 self._ssl_params = None
582 self._ssl_cert = None
584 def _CreateSocket(self, ssl_params, ssl_verify_peer):
585 """Creates a TCP socket and initializes SSL if needed.
587 @type ssl_params: HttpSslParams
588 @param ssl_params: SSL key and certificate
589 @type ssl_verify_peer: bool
590 @param ssl_verify_peer: Whether to require client certificate
591 and compare it with our certificate
594 self._ssl_params = ssl_params
596 sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
598 # Should we enable SSL?
599 self.using_ssl = ssl_params is not None
601 if not self.using_ssl:
604 self._ssl_key = ssl_params.GetKey()
605 self._ssl_cert = ssl_params.GetCertificate()
607 ctx = OpenSSL.SSL.Context(OpenSSL.SSL.SSLv23_METHOD)
608 ctx.set_options(OpenSSL.SSL.OP_NO_SSLv2)
610 ctx.use_privatekey(self._ssl_key)
611 ctx.use_certificate(self._ssl_cert)
612 ctx.check_privatekey()
615 ctx.set_verify(OpenSSL.SSL.VERIFY_PEER |
616 OpenSSL.SSL.VERIFY_FAIL_IF_NO_PEER_CERT,
617 self._SSLVerifyCallback)
619 return OpenSSL.SSL.Connection(ctx, sock)
621 def _SSLVerifyCallback(self, conn, cert, errnum, errdepth, ok):
622 """Verify the certificate provided by the peer
624 We only compare fingerprints. The client must use the same certificate as
628 assert self._ssl_params, "SSL not initialized"
630 return (self._ssl_cert.digest("sha1") == cert.digest("sha1") and
631 self._ssl_cert.digest("md5") == cert.digest("md5"))
634 class HttpMessage(object):
635 """Data structure for HTTP message.
639 self.start_line = None
642 self.decoded_body = None
645 class HttpClientToServerStartLine(object):
646 """Data structure for HTTP request start line.
649 def __init__(self, method, path, version):
652 self.version = version
655 return "%s %s %s" % (self.method, self.path, self.version)
658 class HttpServerToClientStartLine(object):
659 """Data structure for HTTP response start line.
662 def __init__(self, version, code, reason):
663 self.version = version
668 return "%s %s %s" % (self.version, self.code, self.reason)
671 class HttpMessageWriter(object):
672 """Writes an HTTP message to a socket.
675 def __init__(self, sock, msg, write_timeout):
676 """Initializes this class and writes an HTTP message to a socket.
679 @param sock: Socket to be written to
680 @type msg: http.HttpMessage
681 @param msg: HTTP message to be written
682 @type write_timeout: float
683 @param write_timeout: Write timeout for socket
688 self._PrepareMessage()
690 buf = self._FormatMessage()
695 # Send only SOCK_BUF_SIZE bytes at a time
696 data = buf[pos:(pos + SOCK_BUF_SIZE)]
698 sent = SocketOperation(sock, SOCKOP_SEND, data, write_timeout)
703 assert pos == end, "Message wasn't sent completely"
705 def _PrepareMessage(self):
706 """Prepares the HTTP message by setting mandatory headers.
709 # RFC2616, section 4.3: "The presence of a message-body in a request is
710 # signaled by the inclusion of a Content-Length or Transfer-Encoding header
711 # field in the request's message-headers."
713 self._msg.headers[HTTP_CONTENT_LENGTH] = len(self._msg.body)
715 def _FormatMessage(self):
716 """Serializes the HTTP message into a string.
722 buf.write(str(self._msg.start_line))
726 if self._msg.start_line.version != HTTP_0_9:
727 for name, value in self._msg.headers.iteritems():
728 buf.write("%s: %s\r\n" % (name, value))
732 # Add message body if needed
733 if self.HasMessageBody():
734 buf.write(self._msg.body)
737 logging.warning("Ignoring message body")
739 return buf.getvalue()
741 def HasMessageBody(self):
742 """Checks whether the HTTP message contains a body.
744 Can be overridden by subclasses.
747 return bool(self._msg.body)
750 class HttpMessageReader(object):
751 """Reads HTTP message from socket.
755 START_LINE_LENGTH_MAX = None
756 HEADER_LENGTH_MAX = None
758 # Parser state machine
759 PS_START_LINE = "start-line"
760 PS_HEADERS = "headers"
761 PS_BODY = "entity-body"
762 PS_COMPLETE = "complete"
764 def __init__(self, sock, msg, read_timeout):
765 """Reads an HTTP message from a socket.
768 @param sock: Socket to be read from
769 @type msg: http.HttpMessage
770 @param msg: Object for the read message
771 @type read_timeout: float
772 @param read_timeout: Read timeout for socket
778 self.start_line_buffer = None
779 self.header_buffer = StringIO()
780 self.body_buffer = StringIO()
781 self.parser_status = self.PS_START_LINE
782 self.content_length = None
783 self.peer_will_close = None
787 while self.parser_status != self.PS_COMPLETE:
788 # TODO: Don't read more than necessary (Content-Length), otherwise
789 # data might be lost and/or an error could occur
790 data = SocketOperation(sock, SOCKOP_RECV, SOCK_BUF_SIZE, read_timeout)
797 # Do some parsing and error checking while more data arrives
798 buf = self._ContinueParsing(buf, eof)
800 # Must be done only after the buffer has been evaluated
801 # TODO: Connection-length < len(data read) and connection closed
803 self.parser_status in (self.PS_START_LINE,
805 raise HttpError("Connection closed prematurely")
808 buf = self._ContinueParsing(buf, True)
810 assert self.parser_status == self.PS_COMPLETE
811 assert not buf, "Parser didn't read full response"
813 msg.body = self.body_buffer.getvalue()
815 # TODO: Content-type, error handling
817 msg.decoded_body = HttpJsonConverter().Decode(msg.body)
819 msg.decoded_body = None
822 logging.debug("Message body: %s", msg.decoded_body)
824 def _ContinueParsing(self, buf, eof):
825 """Main function for HTTP message state machine.
828 @param buf: Receive buffer
830 @param eof: Whether we've reached EOF on the socket
832 @return: Updated receive buffer
835 # TODO: Use offset instead of slicing when possible
836 if self.parser_status == self.PS_START_LINE:
839 idx = buf.find("\r\n")
841 # RFC2616, section 4.1: "In the interest of robustness, servers SHOULD
842 # ignore any empty line(s) received where a Request-Line is expected.
843 # In other words, if the server is reading the protocol stream at the
844 # beginning of a message and receives a CRLF first, it should ignore
847 # TODO: Limit number of CRLFs/empty lines for safety?
852 self.start_line_buffer = buf[:idx]
854 self._CheckStartLineLength(len(self.start_line_buffer))
856 # Remove status line, including CRLF
859 self.msg.start_line = self.ParseStartLine(self.start_line_buffer)
861 self.parser_status = self.PS_HEADERS
863 # Check whether incoming data is getting too large, otherwise we just
864 # fill our read buffer.
865 self._CheckStartLineLength(len(buf))
869 # TODO: Handle messages without headers
870 if self.parser_status == self.PS_HEADERS:
871 # Wait for header end
872 idx = buf.find("\r\n\r\n")
874 self.header_buffer.write(buf[:idx + 2])
876 self._CheckHeaderLength(self.header_buffer.tell())
878 # Remove headers, including CRLF
883 self.parser_status = self.PS_BODY
885 # Check whether incoming data is getting too large, otherwise we just
886 # fill our read buffer.
887 self._CheckHeaderLength(len(buf))
889 if self.parser_status == self.PS_BODY:
890 # TODO: Implement max size for body_buffer
891 self.body_buffer.write(buf)
894 # Check whether we've read everything
896 # RFC2616, section 4.4: "When a message-body is included with a message,
897 # the transfer-length of that body is determined by one of the following
898 # [...] 5. By the server closing the connection. (Closing the connection
899 # cannot be used to indicate the end of a request body, since that would
900 # leave no possibility for the server to send back a response.)"
902 # TODO: Error when buffer length > Content-Length header
904 self.content_length is None or
905 (self.content_length is not None and
906 self.body_buffer.tell() >= self.content_length)):
907 self.parser_status = self.PS_COMPLETE
911 def _CheckStartLineLength(self, length):
912 """Limits the start line buffer size.
915 @param length: Buffer size
918 if (self.START_LINE_LENGTH_MAX is not None and
919 length > self.START_LINE_LENGTH_MAX):
920 raise HttpError("Start line longer than %d chars" %
921 self.START_LINE_LENGTH_MAX)
923 def _CheckHeaderLength(self, length):
924 """Limits the header buffer size.
927 @param length: Buffer size
930 if (self.HEADER_LENGTH_MAX is not None and
931 length > self.HEADER_LENGTH_MAX):
932 raise HttpError("Headers longer than %d chars" % self.HEADER_LENGTH_MAX)
934 def ParseStartLine(self, start_line):
935 """Parses the start line of a message.
937 Must be overridden by subclass.
939 @type start_line: string
940 @param start_line: Start line string
943 raise NotImplementedError()
945 def _WillPeerCloseConnection(self):
946 """Evaluate whether peer will close the connection.
949 @return: Whether peer will close the connection
952 # RFC2616, section 14.10: "HTTP/1.1 defines the "close" connection option
953 # for the sender to signal that the connection will be closed after
954 # completion of the response. For example,
958 # in either the request or the response header fields indicates that the
959 # connection SHOULD NOT be considered `persistent' (section 8.1) after the
960 # current request/response is complete."
962 hdr_connection = self.msg.headers.get(HTTP_CONNECTION, None)
964 hdr_connection = hdr_connection.lower()
966 # An HTTP/1.1 server is assumed to stay open unless explicitly closed.
967 if self.msg.start_line.version == HTTP_1_1:
968 return (hdr_connection and "close" in hdr_connection)
970 # Some HTTP/1.0 implementations have support for persistent connections,
971 # using rules different than HTTP/1.1.
973 # For older HTTP, Keep-Alive indicates persistent connection.
974 if self.msg.headers.get(HTTP_KEEP_ALIVE):
977 # At least Akamai returns a "Connection: Keep-Alive" header, which was
978 # supposed to be sent by the client.
979 if hdr_connection and "keep-alive" in hdr_connection:
984 def _ParseHeaders(self):
985 """Parses the headers.
987 This function also adjusts internal variables based on header values.
989 RFC2616, section 4.3: The presence of a message-body in a request is
990 signaled by the inclusion of a Content-Length or Transfer-Encoding header
991 field in the request's message-headers.
995 self.header_buffer.seek(0, 0)
996 self.msg.headers = mimetools.Message(self.header_buffer, 0)
998 self.peer_will_close = self._WillPeerCloseConnection()
1000 # Do we have a Content-Length header?
1001 hdr_content_length = self.msg.headers.get(HTTP_CONTENT_LENGTH, None)
1002 if hdr_content_length:
1004 self.content_length = int(hdr_content_length)
1006 self.content_length = None
1007 if self.content_length is not None and self.content_length < 0:
1008 self.content_length = None
1010 # if the connection remains open and a content-length was not provided,
1011 # then assume that the connection WILL close.
1012 if self.content_length is None:
1013 self.peer_will_close = True