4 # Copyright (C) 2007, 2008, 2010 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 utils
38 HTTP_GANETI_VERSION = "Ganeti %s" % constants.RELEASE_VERSION
42 HTTP_NOT_MODIFIED = 304
52 HTTP_DELETE = "DELETE"
56 HTTP_SERVER = "Server"
58 HTTP_USER_AGENT = "User-Agent"
59 HTTP_CONTENT_TYPE = "Content-Type"
60 HTTP_CONTENT_LENGTH = "Content-Length"
61 HTTP_CONNECTION = "Connection"
62 HTTP_KEEP_ALIVE = "Keep-Alive"
63 HTTP_WWW_AUTHENTICATE = "WWW-Authenticate"
64 HTTP_AUTHORIZATION = "Authorization"
65 HTTP_AUTHENTICATION_INFO = "Authentication-Info"
68 HTTP_APP_OCTET_STREAM = "application/octet-stream"
69 HTTP_APP_JSON = "application/json"
71 _SSL_UNEXPECTED_EOF = "Unexpected EOF"
77 SOCKOP_HANDSHAKE) = range(4)
79 # send/receive quantum
83 class HttpError(Exception):
84 """Internal exception for HTTP errors.
86 This should only be used for internal error reporting.
91 class HttpConnectionClosed(Exception):
92 """Internal exception for a closed connection.
94 This should only be used for internal error reporting. Only use
95 it if there's no other way to report this condition.
100 class HttpSessionHandshakeUnexpectedEOF(HttpError):
101 """Internal exception for errors during SSL handshake.
103 This should only be used for internal error reporting.
108 class HttpSocketTimeout(Exception):
109 """Internal exception for socket timeouts.
111 This should only be used for internal error reporting.
116 class HttpException(Exception):
120 def __init__(self, message=None, headers=None):
121 Exception.__init__(self)
122 self.message = message
123 self.headers = headers
126 class HttpBadRequest(HttpException):
129 RFC2616, 10.4.1: The request could not be understood by the server
130 due to malformed syntax. The client SHOULD NOT repeat the request
131 without modifications.
137 class HttpUnauthorized(HttpException):
140 RFC2616, section 10.4.2: The request requires user
141 authentication. The response MUST include a WWW-Authenticate header
142 field (section 14.47) containing a challenge applicable to the
149 class HttpForbidden(HttpException):
152 RFC2616, 10.4.4: The server understood the request, but is refusing
153 to fulfill it. Authorization will not help and the request SHOULD
160 class HttpNotFound(HttpException):
163 RFC2616, 10.4.5: The server has not found anything matching the
164 Request-URI. No indication is given of whether the condition is
165 temporary or permanent.
171 class HttpMethodNotAllowed(HttpException):
172 """405 Method Not Allowed
174 RFC2616, 10.4.6: The method specified in the Request-Line is not
175 allowed for the resource identified by the Request-URI. The response
176 MUST include an Allow header containing a list of valid methods for
177 the requested resource.
183 class HttpNotAcceptable(HttpException):
184 """406 Not Acceptable
186 RFC2616, 10.4.7: The resource identified by the request is only capable of
187 generating response entities which have content characteristics not
188 acceptable according to the accept headers sent in the request.
194 class HttpRequestTimeout(HttpException):
195 """408 Request Timeout
197 RFC2616, 10.4.9: The client did not produce a request within the
198 time that the server was prepared to wait. The client MAY repeat the
199 request without modifications at any later time.
205 class HttpConflict(HttpException):
208 RFC2616, 10.4.10: The request could not be completed due to a
209 conflict with the current state of the resource. This code is only
210 allowed in situations where it is expected that the user might be
211 able to resolve the conflict and resubmit the request.
217 class HttpGone(HttpException):
220 RFC2616, 10.4.11: The requested resource is no longer available at
221 the server and no forwarding address is known. This condition is
222 expected to be considered permanent.
228 class HttpLengthRequired(HttpException):
229 """411 Length Required
231 RFC2616, 10.4.12: The server refuses to accept the request without a
232 defined Content-Length. The client MAY repeat the request if it adds
233 a valid Content-Length header field containing the length of the
234 message-body in the request message.
240 class HttpPreconditionFailed(HttpException):
241 """412 Precondition Failed
243 RFC2616, 10.4.13: The precondition given in one or more of the
244 request-header fields evaluated to false when it was tested on the
251 class HttpUnsupportedMediaType(HttpException):
252 """415 Unsupported Media Type
254 RFC2616, 10.4.16: The server is refusing to service the request because the
255 entity of the request is in a format not supported by the requested resource
256 for the requested method.
262 class HttpInternalServerError(HttpException):
263 """500 Internal Server Error
265 RFC2616, 10.5.1: The server encountered an unexpected condition
266 which prevented it from fulfilling the request.
272 class HttpNotImplemented(HttpException):
273 """501 Not Implemented
275 RFC2616, 10.5.2: The server does not support the functionality
276 required to fulfill the request.
282 class HttpBadGateway(HttpException):
285 RFC2616, 10.5.3: The server, while acting as a gateway or proxy,
286 received an invalid response from the upstream server it accessed in
287 attempting to fulfill the request.
293 class HttpServiceUnavailable(HttpException):
294 """503 Service Unavailable
296 RFC2616, 10.5.4: The server is currently unable to handle the
297 request due to a temporary overloading or maintenance of the server.
303 class HttpGatewayTimeout(HttpException):
304 """504 Gateway Timeout
306 RFC2616, 10.5.5: The server, while acting as a gateway or proxy, did
307 not receive a timely response from the upstream server specified by
308 the URI (e.g. HTTP, FTP, LDAP) or some other auxiliary server
309 (e.g. DNS) it needed to access in attempting to complete the
316 class HttpVersionNotSupported(HttpException):
317 """505 HTTP Version Not Supported
319 RFC2616, 10.5.6: The server does not support, or refuses to support,
320 the HTTP protocol version that was used in the request message.
326 def SocketOperation(sock, op, arg1, timeout):
327 """Wrapper around socket functions.
329 This function abstracts error handling for socket operations, especially
330 for the complicated interaction with OpenSSL.
333 @param sock: Socket for the operation
335 @param op: Operation to execute (SOCKOP_* constants)
337 @param arg1: Parameter for function (if needed)
338 @type timeout: None or float
339 @param timeout: Timeout in seconds or None
340 @return: Return value of socket function
343 # TODO: event_poll/event_check/override
344 if op in (SOCKOP_SEND, SOCKOP_HANDSHAKE):
345 event_poll = select.POLLOUT
347 elif op == SOCKOP_RECV:
348 event_poll = select.POLLIN
350 elif op == SOCKOP_SHUTDOWN:
353 # The timeout is only used when OpenSSL requests polling for a condition.
354 # It is not advisable to have no timeout for shutdown.
358 raise AssertionError("Invalid socket operation")
360 # Handshake is only supported by SSL sockets
361 if (op == SOCKOP_HANDSHAKE and
362 not isinstance(sock, OpenSSL.SSL.ConnectionType)):
365 # No override by default
369 # Poll only for certain operations and when asked for by an override
370 if event_override or op in (SOCKOP_SEND, SOCKOP_RECV, SOCKOP_HANDSHAKE):
372 wait_for_event = event_override
374 wait_for_event = event_poll
376 event = utils.WaitForFdCondition(sock, wait_for_event, timeout)
378 raise HttpSocketTimeout()
380 if event & (select.POLLNVAL | select.POLLHUP | select.POLLERR):
381 # Let the socket functions handle these
384 if not event & wait_for_event:
392 if op == SOCKOP_SEND:
393 return sock.send(arg1)
395 elif op == SOCKOP_RECV:
396 return sock.recv(arg1)
398 elif op == SOCKOP_SHUTDOWN:
399 if isinstance(sock, OpenSSL.SSL.ConnectionType):
400 # PyOpenSSL's shutdown() doesn't take arguments
401 return sock.shutdown()
403 return sock.shutdown(arg1)
405 elif op == SOCKOP_HANDSHAKE:
406 return sock.do_handshake()
408 except OpenSSL.SSL.WantWriteError:
409 # OpenSSL wants to write, poll for POLLOUT
410 event_override = select.POLLOUT
413 except OpenSSL.SSL.WantReadError:
414 # OpenSSL wants to read, poll for POLLIN
415 event_override = select.POLLIN | select.POLLPRI
418 except OpenSSL.SSL.WantX509LookupError:
421 except OpenSSL.SSL.ZeroReturnError, err:
422 # SSL Connection has been closed. In SSL 3.0 and TLS 1.0, this only
423 # occurs if a closure alert has occurred in the protocol, i.e. the
424 # connection has been closed cleanly. Note that this does not
425 # necessarily mean that the transport layer (e.g. a socket) has been
427 if op == SOCKOP_SEND:
428 # Can happen during a renegotiation
429 raise HttpConnectionClosed(err.args)
430 elif op == SOCKOP_RECV:
433 # SSL_shutdown shouldn't return SSL_ERROR_ZERO_RETURN
434 raise socket.error(err.args)
436 except OpenSSL.SSL.SysCallError, err:
437 if op == SOCKOP_SEND:
438 # arg1 is the data when writing
439 if err.args and err.args[0] == -1 and arg1 == "":
440 # errors when writing empty strings are expected
444 if err.args == (-1, _SSL_UNEXPECTED_EOF):
445 if op == SOCKOP_RECV:
447 elif op == SOCKOP_HANDSHAKE:
448 # Can happen if peer disconnects directly after the connection is
450 raise HttpSessionHandshakeUnexpectedEOF(err.args)
452 raise socket.error(err.args)
454 except OpenSSL.SSL.Error, err:
455 raise socket.error(err.args)
457 except socket.error, err:
458 if err.args and err.args[0] == errno.EAGAIN:
465 def ShutdownConnection(sock, close_timeout, write_timeout, msgreader, force):
466 """Closes the connection.
469 @param sock: Socket to be shut down
470 @type close_timeout: float
471 @param close_timeout: How long to wait for the peer to close
473 @type write_timeout: float
474 @param write_timeout: Write timeout for shutdown
475 @type msgreader: http.HttpMessageReader
476 @param msgreader: Request message reader, used to determine whether
477 peer should close connection
479 @param force: Whether to forcibly close the connection without
483 #print msgreader.peer_will_close, force
484 if msgreader and msgreader.peer_will_close and not force:
485 # Wait for peer to close
487 # Check whether it's actually closed
488 if not SocketOperation(sock, SOCKOP_RECV, 1, close_timeout):
490 except (socket.error, HttpError, HttpSocketTimeout):
491 # Ignore errors at this stage
494 # Close the connection from our side
496 # We don't care about the return value, see NOTES in SSL_shutdown(3).
497 SocketOperation(sock, SOCKOP_SHUTDOWN, socket.SHUT_RDWR,
499 except HttpSocketTimeout:
500 raise HttpError("Timeout while shutting down connection")
501 except socket.error, err:
503 if not (err.args and err.args[0] == errno.ENOTCONN):
504 raise HttpError("Error while shutting down connection: %s" % err)
507 def Handshake(sock, write_timeout):
508 """Shakes peer's hands.
511 @param sock: Socket to be shut down
512 @type write_timeout: float
513 @param write_timeout: Write timeout for handshake
517 return SocketOperation(sock, SOCKOP_HANDSHAKE, None, write_timeout)
518 except HttpSocketTimeout:
519 raise HttpError("Timeout during SSL handshake")
520 except socket.error, err:
521 raise HttpError("Error in SSL handshake: %s" % err)
525 """Initializes the SSL infrastructure.
527 This function is idempotent.
530 if not OpenSSL.rand.status():
531 raise EnvironmentError("OpenSSL could not collect enough entropy"
534 # TODO: Maybe add some additional seeding for OpenSSL's PRNG
537 class HttpSslParams(object):
538 """Data class for SSL key and certificate.
541 def __init__(self, ssl_key_path, ssl_cert_path):
542 """Initializes this class.
544 @type ssl_key_path: string
545 @param ssl_key_path: Path to file containing SSL key in PEM format
546 @type ssl_cert_path: string
547 @param ssl_cert_path: Path to file containing SSL certificate
551 self.ssl_key_pem = utils.ReadFile(ssl_key_path)
552 self.ssl_cert_pem = utils.ReadFile(ssl_cert_path)
555 return OpenSSL.crypto.load_privatekey(OpenSSL.crypto.FILETYPE_PEM,
558 def GetCertificate(self):
559 return OpenSSL.crypto.load_certificate(OpenSSL.crypto.FILETYPE_PEM,
563 class HttpBase(object):
564 """Base class for HTTP server and client.
568 self.using_ssl = None
569 self._ssl_params = None
571 self._ssl_cert = None
573 def _CreateSocket(self, ssl_params, ssl_verify_peer, family):
574 """Creates a TCP socket and initializes SSL if needed.
576 @type ssl_params: HttpSslParams
577 @param ssl_params: SSL key and certificate
578 @type ssl_verify_peer: bool
579 @param ssl_verify_peer: Whether to require client certificate
580 and compare it with our certificate
582 @param family: socket.AF_INET | socket.AF_INET6
585 assert family in (socket.AF_INET, socket.AF_INET6)
587 self._ssl_params = ssl_params
588 sock = socket.socket(family, socket.SOCK_STREAM)
590 # Should we enable SSL?
591 self.using_ssl = ssl_params is not None
593 if not self.using_ssl:
596 self._ssl_key = ssl_params.GetKey()
597 self._ssl_cert = ssl_params.GetCertificate()
599 ctx = OpenSSL.SSL.Context(OpenSSL.SSL.SSLv23_METHOD)
600 ctx.set_options(OpenSSL.SSL.OP_NO_SSLv2)
601 ctx.set_cipher_list(constants.OPENSSL_CIPHERS)
603 ctx.use_privatekey(self._ssl_key)
604 ctx.use_certificate(self._ssl_cert)
605 ctx.check_privatekey()
608 ctx.set_verify(OpenSSL.SSL.VERIFY_PEER |
609 OpenSSL.SSL.VERIFY_FAIL_IF_NO_PEER_CERT,
610 self._SSLVerifyCallback)
612 return OpenSSL.SSL.Connection(ctx, sock)
614 def _SSLVerifyCallback(self, conn, cert, errnum, errdepth, ok):
615 """Verify the certificate provided by the peer
617 We only compare fingerprints. The client must use the same certificate as
621 # some parameters are unused, but this is the API
622 # pylint: disable-msg=W0613
623 assert self._ssl_params, "SSL not initialized"
625 return (self._ssl_cert.digest("sha1") == cert.digest("sha1") and
626 self._ssl_cert.digest("md5") == cert.digest("md5"))
629 class HttpMessage(object):
630 """Data structure for HTTP message.
634 self.start_line = None
639 class HttpClientToServerStartLine(object):
640 """Data structure for HTTP request start line.
643 def __init__(self, method, path, version):
646 self.version = version
649 return "%s %s %s" % (self.method, self.path, self.version)
652 class HttpServerToClientStartLine(object):
653 """Data structure for HTTP response start line.
656 def __init__(self, version, code, reason):
657 self.version = version
662 return "%s %s %s" % (self.version, self.code, self.reason)
665 class HttpMessageWriter(object):
666 """Writes an HTTP message to a socket.
669 def __init__(self, sock, msg, write_timeout):
670 """Initializes this class and writes an HTTP message to a socket.
673 @param sock: Socket to be written to
674 @type msg: http.HttpMessage
675 @param msg: HTTP message to be written
676 @type write_timeout: float
677 @param write_timeout: Write timeout for socket
682 self._PrepareMessage()
684 buf = self._FormatMessage()
689 # Send only SOCK_BUF_SIZE bytes at a time
690 data = buf[pos:(pos + SOCK_BUF_SIZE)]
692 sent = SocketOperation(sock, SOCKOP_SEND, data, write_timeout)
697 assert pos == end, "Message wasn't sent completely"
699 def _PrepareMessage(self):
700 """Prepares the HTTP message by setting mandatory headers.
703 # RFC2616, section 4.3: "The presence of a message-body in a request is
704 # signaled by the inclusion of a Content-Length or Transfer-Encoding header
705 # field in the request's message-headers."
707 self._msg.headers[HTTP_CONTENT_LENGTH] = len(self._msg.body)
709 def _FormatMessage(self):
710 """Serializes the HTTP message into a string.
716 buf.write(str(self._msg.start_line))
720 if self._msg.start_line.version != HTTP_0_9:
721 for name, value in self._msg.headers.iteritems():
722 buf.write("%s: %s\r\n" % (name, value))
726 # Add message body if needed
727 if self.HasMessageBody():
728 buf.write(self._msg.body)
731 logging.warning("Ignoring message body")
733 return buf.getvalue()
735 def HasMessageBody(self):
736 """Checks whether the HTTP message contains a body.
738 Can be overridden by subclasses.
741 return bool(self._msg.body)
744 class HttpMessageReader(object):
745 """Reads HTTP message from socket.
749 START_LINE_LENGTH_MAX = None
750 HEADER_LENGTH_MAX = None
752 # Parser state machine
753 PS_START_LINE = "start-line"
754 PS_HEADERS = "headers"
755 PS_BODY = "entity-body"
756 PS_COMPLETE = "complete"
758 def __init__(self, sock, msg, read_timeout):
759 """Reads an HTTP message from a socket.
762 @param sock: Socket to be read from
763 @type msg: http.HttpMessage
764 @param msg: Object for the read message
765 @type read_timeout: float
766 @param read_timeout: Read timeout for socket
772 self.start_line_buffer = None
773 self.header_buffer = StringIO()
774 self.body_buffer = StringIO()
775 self.parser_status = self.PS_START_LINE
776 self.content_length = None
777 self.peer_will_close = None
781 while self.parser_status != self.PS_COMPLETE:
782 # TODO: Don't read more than necessary (Content-Length), otherwise
783 # data might be lost and/or an error could occur
784 data = SocketOperation(sock, SOCKOP_RECV, SOCK_BUF_SIZE, read_timeout)
791 # Do some parsing and error checking while more data arrives
792 buf = self._ContinueParsing(buf, eof)
794 # Must be done only after the buffer has been evaluated
795 # TODO: Content-Length < len(data read) and connection closed
797 self.parser_status in (self.PS_START_LINE,
799 raise HttpError("Connection closed prematurely")
802 buf = self._ContinueParsing(buf, True)
804 assert self.parser_status == self.PS_COMPLETE
805 assert not buf, "Parser didn't read full response"
808 msg.body = self.body_buffer.getvalue()
810 def _ContinueParsing(self, buf, eof):
811 """Main function for HTTP message state machine.
814 @param buf: Receive buffer
816 @param eof: Whether we've reached EOF on the socket
818 @return: Updated receive buffer
821 # TODO: Use offset instead of slicing when possible
822 if self.parser_status == self.PS_START_LINE:
825 idx = buf.find("\r\n")
827 # RFC2616, section 4.1: "In the interest of robustness, servers SHOULD
828 # ignore any empty line(s) received where a Request-Line is expected.
829 # In other words, if the server is reading the protocol stream at the
830 # beginning of a message and receives a CRLF first, it should ignore
833 # TODO: Limit number of CRLFs/empty lines for safety?
838 self.start_line_buffer = buf[:idx]
840 self._CheckStartLineLength(len(self.start_line_buffer))
842 # Remove status line, including CRLF
845 self.msg.start_line = self.ParseStartLine(self.start_line_buffer)
847 self.parser_status = self.PS_HEADERS
849 # Check whether incoming data is getting too large, otherwise we just
850 # fill our read buffer.
851 self._CheckStartLineLength(len(buf))
855 # TODO: Handle messages without headers
856 if self.parser_status == self.PS_HEADERS:
857 # Wait for header end
858 idx = buf.find("\r\n\r\n")
860 self.header_buffer.write(buf[:idx + 2])
862 self._CheckHeaderLength(self.header_buffer.tell())
864 # Remove headers, including CRLF
869 self.parser_status = self.PS_BODY
871 # Check whether incoming data is getting too large, otherwise we just
872 # fill our read buffer.
873 self._CheckHeaderLength(len(buf))
875 if self.parser_status == self.PS_BODY:
876 # TODO: Implement max size for body_buffer
877 self.body_buffer.write(buf)
880 # Check whether we've read everything
882 # RFC2616, section 4.4: "When a message-body is included with a message,
883 # the transfer-length of that body is determined by one of the following
884 # [...] 5. By the server closing the connection. (Closing the connection
885 # cannot be used to indicate the end of a request body, since that would
886 # leave no possibility for the server to send back a response.)"
888 # TODO: Error when buffer length > Content-Length header
890 self.content_length is None or
891 (self.content_length is not None and
892 self.body_buffer.tell() >= self.content_length)):
893 self.parser_status = self.PS_COMPLETE
897 def _CheckStartLineLength(self, length):
898 """Limits the start line buffer size.
901 @param length: Buffer size
904 if (self.START_LINE_LENGTH_MAX is not None and
905 length > self.START_LINE_LENGTH_MAX):
906 raise HttpError("Start line longer than %d chars" %
907 self.START_LINE_LENGTH_MAX)
909 def _CheckHeaderLength(self, length):
910 """Limits the header buffer size.
913 @param length: Buffer size
916 if (self.HEADER_LENGTH_MAX is not None and
917 length > self.HEADER_LENGTH_MAX):
918 raise HttpError("Headers longer than %d chars" % self.HEADER_LENGTH_MAX)
920 def ParseStartLine(self, start_line):
921 """Parses the start line of a message.
923 Must be overridden by subclass.
925 @type start_line: string
926 @param start_line: Start line string
929 raise NotImplementedError()
931 def _WillPeerCloseConnection(self):
932 """Evaluate whether peer will close the connection.
935 @return: Whether peer will close the connection
938 # RFC2616, section 14.10: "HTTP/1.1 defines the "close" connection option
939 # for the sender to signal that the connection will be closed after
940 # completion of the response. For example,
944 # in either the request or the response header fields indicates that the
945 # connection SHOULD NOT be considered `persistent' (section 8.1) after the
946 # current request/response is complete."
948 hdr_connection = self.msg.headers.get(HTTP_CONNECTION, None)
950 hdr_connection = hdr_connection.lower()
952 # An HTTP/1.1 server is assumed to stay open unless explicitly closed.
953 if self.msg.start_line.version == HTTP_1_1:
954 return (hdr_connection and "close" in hdr_connection)
956 # Some HTTP/1.0 implementations have support for persistent connections,
957 # using rules different than HTTP/1.1.
959 # For older HTTP, Keep-Alive indicates persistent connection.
960 if self.msg.headers.get(HTTP_KEEP_ALIVE):
963 # At least Akamai returns a "Connection: Keep-Alive" header, which was
964 # supposed to be sent by the client.
965 if hdr_connection and "keep-alive" in hdr_connection:
970 def _ParseHeaders(self):
971 """Parses the headers.
973 This function also adjusts internal variables based on header values.
975 RFC2616, section 4.3: The presence of a message-body in a request is
976 signaled by the inclusion of a Content-Length or Transfer-Encoding header
977 field in the request's message-headers.
981 self.header_buffer.seek(0, 0)
982 self.msg.headers = mimetools.Message(self.header_buffer, 0)
984 self.peer_will_close = self._WillPeerCloseConnection()
986 # Do we have a Content-Length header?
987 hdr_content_length = self.msg.headers.get(HTTP_CONTENT_LENGTH, None)
988 if hdr_content_length:
990 self.content_length = int(hdr_content_length)
991 except (TypeError, ValueError):
992 self.content_length = None
993 if self.content_length is not None and self.content_length < 0:
994 self.content_length = None
996 # if the connection remains open and a content-length was not provided,
997 # then assume that the connection WILL close.
998 if self.content_length is None:
999 self.peer_will_close = True