root / lib / confd / server.py @ d21eda27
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#!/usr/bin/python
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#
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# Copyright (C) 2009, Google Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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# 02110-1301, USA.
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"""Ganeti configuration daemon server library.
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Ganeti-confd is a daemon to query master candidates for configuration values.
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It uses UDP+HMAC for authentication with a global cluster key.
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"""
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import logging |
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import time |
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from ganeti import constants |
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from ganeti import objects |
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from ganeti import errors |
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from ganeti import utils |
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from ganeti import serializer |
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from ganeti.confd import querylib |
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class ConfdProcessor(object): |
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"""A processor for confd requests.
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"""
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DISPATCH_TABLE = { |
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constants.CONFD_REQ_PING: querylib.PingQuery, |
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constants.CONFD_REQ_NODE_ROLE_BYNAME: querylib.ConfdQuery, |
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constants.CONFD_REQ_NODE_PIP_BY_INSTANCE_IP: querylib.ConfdQuery, |
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} |
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def __init__(self, reader): |
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"""Constructor for ConfdProcessor
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@type reader: L{ssconf.SimpleConfigReader}
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@param reader: ConfigReader to use to access the config
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"""
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self.reader = reader
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self.hmac_key = utils.ReadFile(constants.HMAC_CLUSTER_KEY)
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assert \
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not constants.CONFD_REQS.symmetric_difference(self.DISPATCH_TABLE), \ |
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"DISPATCH_TABLE is unaligned with CONFD_REQS"
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def ExecQuery(self, payload_in, ip, port): |
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"""Process a single UDP request from a client.
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@type payload_in: string
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@param payload_in: request raw data
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@type ip: string
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@param ip: source ip address
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@param port: integer
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@type port: source port
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"""
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try:
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request = self.ExtractRequest(payload_in)
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reply, rsalt = self.ProcessRequest(request)
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payload_out = self.PackReply(reply, rsalt)
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return payload_out
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except errors.ConfdRequestError, err:
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logging.info('Ignoring broken query from %s:%d: %s' % (ip, port, err))
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return None |
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def ExtractRequest(self, payload): |
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"""Extracts a ConfdRequest object from a serialized hmac signed string.
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This functions also performs signature/timestamp validation.
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"""
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current_time = time.time() |
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logging.debug("Extracting request with size: %d" % (len(payload))) |
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try:
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(message, salt) = serializer.LoadSigned(payload, self.hmac_key)
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except errors.SignatureError, err:
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msg = "invalid signature: %s" % err
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raise errors.ConfdRequestError(msg)
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try:
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message_timestamp = int(salt)
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except (ValueError, TypeError): |
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msg = "non-integer timestamp: %s" % salt
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raise errors.ConfdRequestError(msg)
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skew = abs(current_time - message_timestamp)
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if skew > constants.CONFD_MAX_CLOCK_SKEW:
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msg = "outside time range (skew: %d)" % skew
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raise errors.ConfdRequestError(msg)
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try:
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request = objects.ConfdRequest.FromDict(message) |
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except AttributeError, err: |
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raise errors.ConfdRequestError('%s' % err) |
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return request
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def ProcessRequest(self, request): |
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"""Process one ConfdRequest request, and produce an answer
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@type request: L{objects.ConfdRequest}
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@rtype: (L{objects.ConfdReply}, string)
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@return: tuple of reply and salt to add to the signature
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"""
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logging.debug("Processing request: %s" % request)
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if request.protocol != constants.CONFD_PROTOCOL_VERSION:
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msg = "wrong protocol version %d" % request.protocol
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raise errors.ConfdRequestError(msg)
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if request.type not in constants.CONFD_REQS: |
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msg = "wrong request type %d" % request.type
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raise errors.ConfdRequestError(msg)
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rsalt = request.rsalt |
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if not rsalt: |
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msg = "missing requested salt"
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raise errors.ConfdRequestError(msg)
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query_object = self.DISPATCH_TABLE[request.type](self.reader) |
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status, answer = query_object.Exec(request.query) |
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reply = objects.ConfdReply( |
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protocol=constants.CONFD_PROTOCOL_VERSION, |
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status=status, |
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answer=answer, |
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serial=self.reader.GetConfigSerialNo(),
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) |
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logging.debug("Sending reply: %s" % reply)
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return (reply, rsalt)
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def PackReply(self, reply, rsalt): |
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"""Serialize and sign the given reply, with salt rsalt
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@type reply: L{objects.ConfdReply}
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@type rsalt: string
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"""
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return serializer.DumpSigned(reply.ToDict(), self.hmac_key, rsalt) |
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