Commit 71f27d19 authored by Guido Trotter's avatar Guido Trotter

confd.server.ConfdProcessor

A ConfdProcessor is the job processor for a confd query.
It's responsible for all the processing, from unpacking it, verifying
it, to calculating the result.
Signed-off-by: default avatarGuido Trotter <ultrotter@google.com>
Reviewed-by: default avatarIustin Pop <iustin@google.com>
parent 12426ae1
......@@ -113,7 +113,8 @@ http_PYTHON = \
lib/http/server.py
confd_PYTHON = \
lib/confd/__init__.py
lib/confd/__init__.py \
lib/confd/server.py
docrst = \
doc/admin.rst \
......
#!/usr/bin/python
#
# Copyright (C) 2009, Google Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
"""Ganeti configuration daemon server library.
Ganeti-confd is a daemon to query master candidates for configuration values.
It uses UDP+HMAC for authentication with a global cluster key.
"""
import sys
import logging
import time
from optparse import OptionParser
from ganeti import constants
from ganeti import objects
from ganeti import errors
from ganeti import utils
from ganeti import ssconf
from ganeti import serializer
class ConfdProcessor(object):
"""A processor for confd requests.
"""
DISPATCH_TABLE = {
}
def __init__(self, reader):
"""Constructor for ConfdAsyncUDPServer
@type reader: L{ssconf.SimpleConfigReader}
@param reader: ConfigReader to use to access the config
"""
self.reader = reader
self.hmac_key = utils.ReadFile(constants.HMAC_CLUSTER_KEY)
def ExecQuery(self, payload_in, ip, port):
"""Process a single UDP request from a client.
@type payload_in: string
@param payload_in: request raw data
@type ip: string
@param ip: source ip address
@param port: integer
@type port: source port
"""
try:
request = self.ExtractRequest(payload_in)
reply, rsalt = self.ProcessRequest(request)
payload_out = self.PackReply(reply, rsalt)
return payload_out
except errors.ConfdRequestError, err:
logging.info('Ignoring broken query from %s:%d: %s' % (ip, port, err))
return None
def ExtractRequest(self, payload):
"""Extracts a ConfdRequest object from a serialized hmac signed string.
This functions also performs signature/timestamp validation.
"""
current_time = time.time()
logging.debug("Extracting request with size: %d" % (len(payload)))
try:
(message, salt) = serializer.LoadSigned(payload, self.hmac_key)
except errors.SignatureError, err:
msg = "invalid signature: %s" % err
raise errors.ConfdRequestError(msg)
try:
message_timestamp = int(salt)
except (ValueError, TypeError):
msg = "non-integer timestamp: %s" % salt
raise errors.ConfdRequestError(msg)
skew = abs(current_time - message_timestamp)
if skew > constants.CONFD_MAX_CLOCK_SKEW:
msg = "outside time range (skew: %d)" % skew
raise errors.ConfdRequestError(msg)
try:
request = objects.ConfdRequest.FromDict(message)
except AttributeError, err:
raise errors.ConfdRequestError('%s' % err)
return request
def ProcessRequest(self, request):
"""Process one ConfdRequest request, and produce an answer
@type request: L{objects.ConfdRequest}
@rtype: (L{objects.ConfdReply}, string)
@return: tuple of reply and salt to add to the signature
"""
logging.debug("Processing request: %s" % request)
if request.protocol != constants.CONFD_PROTOCOL_VERSION:
msg = "wrong protocol version %d" % request.protocol
raise errors.ConfdRequestError(msg)
if request.type not in constants.CONFD_REQS:
msg = "wrong request type %d" % request.type
raise errors.ConfdRequestError(msg)
rsalt = request.rsalt
if not rsalt:
msg = "missing requested salt"
raise errors.ConfdRequestError(msg)
if request.type not in self.DISPATCH_TABLE:
answer = 'not implemented'
status = constants.CONFD_REPL_STATUS_NOTIMPLEMENTED
reply = objects.ConfdReply(
protocol=constants.CONFD_PROTOCOL_VERSION,
status=status,
answer=answer,
)
else:
# TODO: actually dispatch queries to some classes to handle them
assert False, "DISPATCH_TABLE is populated but handler is not"
logging.debug("Sending reply: %s" % reply)
return (reply, rsalt)
def PackReply(self, reply, rsalt):
"""Serialize and sign the given reply, with salt rsalt
@type reply: L{objects.ConfdReply}
@type rsalt: string
"""
return serializer.DumpSigned(reply.ToDict(), self.hmac_key, rsalt)
......@@ -647,3 +647,8 @@ CONFD_REPL_STATUSES = frozenset([
CONFD_NODE_ROLE_OFFLINE,
CONFD_NODE_ROLE_DRAINED) = range(4)
# Each request is "salted" by the current timestamp.
# This constants decides how many seconds of skew to accept.
# TODO: make this a default and allow the value to be more configurable
CONFD_MAX_CLOCK_SKEW = 300
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