#!@PYTHON@ # Copyright (C) 2010-2012 Internet Systems Consortium. # # Permission to use, copy, modify, and distribute this software for any # purpose with or without fee is hereby granted, provided that the above # copyright notice and this permission notice appear in all copies. # # THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SYSTEMS CONSORTIUM # DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL # INTERNET SYSTEMS CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, # INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING # FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, # NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION # WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. import sys; sys.path.append ('@@PYTHONPATH@@') import isc import isc.cc import threading import struct import signal from isc.datasrc import DataSourceClient, ZoneFinder, ZoneJournalReader from socketserver import * import os from isc.config.ccsession import * from isc.cc import SessionError, SessionTimeout from isc.notify import notify_out import isc.util.process import socket import select import errno from optparse import OptionParser, OptionValueError from isc.util import socketserver_mixin import isc.server_common.tsig_keyring from isc.log_messages.xfrout_messages import * isc.log.init("b10-xfrout", buffer=True) logger = isc.log.Logger("xfrout") # Pending system-wide debug level definitions, the ones we # use here are hardcoded for now DBG_PROCESS = logger.DBGLVL_TRACE_BASIC DBG_COMMANDS = logger.DBGLVL_TRACE_DETAIL DBG_XFROUT_TRACE = logger.DBGLVL_TRACE_BASIC try: from libutil_io_python import * from pydnspp import * except ImportError as e: # C++ loadable module may not be installed; even so the xfrout process # must keep running, so we warn about it and move forward. logger.error(XFROUT_IMPORT, str(e)) from isc.acl.acl import ACCEPT, REJECT, DROP, LoaderError from isc.acl.dns import REQUEST_LOADER isc.util.process.rename() class XfroutConfigError(Exception): """An exception indicating an error in updating xfrout configuration. This exception is raised when the xfrout process encouters an error in handling configuration updates. Not all syntax error can be caught at the module-CC layer, so xfrout needs to (explicitly or implicitly) validate the given configuration data itself. When it finds an error it raises this exception (either directly or by converting an exception from other modules) as a unified error in configuration. """ pass class XfroutSessionError(Exception): '''An exception raised for some unexpected events during an xfrout session. ''' pass def init_paths(): global SPECFILE_PATH global AUTH_SPECFILE_PATH global UNIX_SOCKET_FILE if "B10_FROM_BUILD" in os.environ: SPECFILE_PATH = os.environ["B10_FROM_BUILD"] + "/src/bin/xfrout" AUTH_SPECFILE_PATH = os.environ["B10_FROM_BUILD"] + "/src/bin/auth" if "B10_FROM_SOURCE_LOCALSTATEDIR" in os.environ: UNIX_SOCKET_FILE = os.environ["B10_FROM_SOURCE_LOCALSTATEDIR"] + \ "/auth_xfrout_conn" else: UNIX_SOCKET_FILE = os.environ["B10_FROM_BUILD"] + "/auth_xfrout_conn" else: PREFIX = "@prefix@" DATAROOTDIR = "@datarootdir@" SPECFILE_PATH = "@datadir@/@PACKAGE@".replace("${datarootdir}", DATAROOTDIR).replace("${prefix}", PREFIX) AUTH_SPECFILE_PATH = SPECFILE_PATH if "BIND10_XFROUT_SOCKET_FILE" in os.environ: UNIX_SOCKET_FILE = os.environ["BIND10_XFROUT_SOCKET_FILE"] else: UNIX_SOCKET_FILE = "@@LOCALSTATEDIR@@/@PACKAGE_NAME@/auth_xfrout_conn" init_paths() SPECFILE_LOCATION = SPECFILE_PATH + "/xfrout.spec" AUTH_SPECFILE_LOCATION = AUTH_SPECFILE_PATH + os.sep + "auth.spec" VERBOSE_MODE = False XFROUT_DNS_HEADER_SIZE = 12 # protocol constant XFROUT_MAX_MESSAGE_SIZE = 65535 # ditto # borrowed from xfrin.py @ #1298. We should eventually unify it. def format_zone_str(zone_name, zone_class): """Helper function to format a zone name and class as a string of the form '/'. Parameters: zone_name (isc.dns.Name) name to format zone_class (isc.dns.RRClass) class to format """ return zone_name.to_text(True) + '/' + str(zone_class) # borrowed from xfrin.py @ #1298. def format_addrinfo(addrinfo): """Helper function to format the addrinfo as a string of the form : (for IPv4) or []:port (for IPv6). For unix domain sockets, and unknown address families, it returns a basic string conversion of the third element of the passed tuple. Parameters: addrinfo: a 3-tuple consisting of address family, socket type, and, depending on the family, either a 2-tuple with the address and port, or a filename """ try: if addrinfo[0] == socket.AF_INET: return str(addrinfo[2][0]) + ":" + str(addrinfo[2][1]) elif addrinfo[0] == socket.AF_INET6: return "[" + str(addrinfo[2][0]) + "]:" + str(addrinfo[2][1]) else: return str(addrinfo[2]) except IndexError: raise TypeError("addrinfo argument to format_addrinfo() does not " "appear to be consisting of (family, socktype, (addr, port))") def get_rrset_len(rrset): """Returns the wire length of the given RRset""" bytes = bytearray() rrset.to_wire(bytes) return len(bytes) def get_soa_serial(soa_rdata): '''Extract the serial field of an SOA RDATA and returns it as an Serial object. ''' return Serial(int(soa_rdata.to_text().split()[2])) class XfroutSession(): def __init__(self, sock_fd, request_data, server, tsig_key_ring, remote, default_acl, zone_config, client_class=DataSourceClient, **counters): self._sock_fd = sock_fd self._request_data = request_data self._server = server self._tsig_key_ring = tsig_key_ring self._tsig_ctx = None self._tsig_len = 0 self._remote = remote self._request_type = None self._request_typestr = None self._acl = default_acl self._zone_config = zone_config self.ClientClass = client_class # parameterize this for testing self._soa = None # will be set in _xfrout_setup or in tests self._jnl_reader = None # will be set to a reader for IXFR # Extract counter handler from the `counters` argument and add # it to the class attribute of the name whose prefix is # '_counter_' '_inc_' or '_dec_' for (k, v) in counters.items(): if k.find('counter_') == 0 or k.find('inc_') == 0 \ or k.find('dec_') == 0: setattr(self, "_%s" % k, v) self._handle() def create_tsig_ctx(self, tsig_record, tsig_key_ring): return TSIGContext(tsig_record.get_name(), tsig_record.get_rdata().get_algorithm(), tsig_key_ring) def _handle(self): ''' Handle a xfrout query, send xfrout response(s). This is separated from the constructor so that we can override it from tests. ''' # Check the xfrout quota. We do both increase/decrease in this # method so it's clear we always release it once acuired. quota_ok = self._server.increase_transfers_counter() ex = None try: self.dns_xfrout_start(self._sock_fd, self._request_data, quota_ok) except Exception as e: # To avoid resource leak we need catch all possible exceptions # We log it later to exclude the case where even logger raises # an exception. ex = e # Release any critical resources if quota_ok: self._server.decrease_transfers_counter() self._close_socket() if ex is not None: logger.error(XFROUT_HANDLE_QUERY_ERROR, ex) def _close_socket(self): '''Simply close the socket via the given FD. This is a dedicated subroutine of handle() and is sepsarated from it for the convenience of tests. ''' os.close(self._sock_fd) def _check_request_tsig(self, msg, request_data): ''' If request has a tsig record, perform tsig related checks ''' tsig_record = msg.get_tsig_record() if tsig_record is not None: self._tsig_len = tsig_record.get_length() self._tsig_ctx = self.create_tsig_ctx(tsig_record, self._tsig_key_ring) tsig_error = self._tsig_ctx.verify(tsig_record, request_data) if tsig_error != TSIGError.NOERROR: return Rcode.NOTAUTH() return Rcode.NOERROR() def _parse_query_message(self, mdata): ''' parse query message to [socket,message]''' #TODO, need to add parseHeader() in case the message header is invalid try: msg = Message(Message.PARSE) Message.from_wire(msg, mdata) except Exception as err: # Exception is too broad logger.error(XFROUT_PARSE_QUERY_ERROR, err) return Rcode.FORMERR(), None # TSIG related checks rcode = self._check_request_tsig(msg, mdata) if rcode != Rcode.NOERROR(): return rcode, msg # Make sure the question is valid. This should be ensured by # the auth server, but since it's far from xfrout itself, we check # it by ourselves. A viloation would be an internal bug, so we # raise and stop here rather than returning a FORMERR or SERVFAIL. if msg.get_rr_count(Message.SECTION_QUESTION) != 1: raise RuntimeError('Invalid number of question for XFR: ' + str(msg.get_rr_count(Message.SECTION_QUESTION))) question = msg.get_question()[0] # Identify the request type self._request_type = question.get_type() if self._request_type == RRType.AXFR(): self._request_typestr = 'AXFR' elif self._request_type == RRType.IXFR(): self._request_typestr = 'IXFR' else: # Likewise, this should be impossible. raise RuntimeError('Unexpected XFR type: ' + str(self._request_type)) # ACL checks zone_name = question.get_name() zone_class = question.get_class() acl = self._get_transfer_acl(zone_name, zone_class) acl_result = acl.execute( isc.acl.dns.RequestContext(self._remote[2], msg.get_tsig_record())) if acl_result == DROP: logger.debug(DBG_XFROUT_TRACE, XFROUT_QUERY_DROPPED, self._request_type, format_addrinfo(self._remote), format_zone_str(zone_name, zone_class)) return None, None elif acl_result == REJECT: # count rejected Xfr request by each zone name self._counter_xfrrej(zone_name.to_text()) logger.debug(DBG_XFROUT_TRACE, XFROUT_QUERY_REJECTED, self._request_type, format_addrinfo(self._remote), format_zone_str(zone_name, zone_class)) return Rcode.REFUSED(), msg return rcode, msg def _get_transfer_acl(self, zone_name, zone_class): '''Return the ACL that should be applied for a given zone. The zone is identified by a tuple of name and RR class. If a per zone configuration for the zone exists and contains transfer_acl, that ACL will be used; otherwise, the default ACL will be used. ''' # Internally zone names are managed in lower cased label characters, # so we first need to convert the name. zone_name_lower = Name(zone_name.to_text(), True) config_key = (zone_class.to_text(), zone_name_lower.to_text()) if config_key in self._zone_config and \ 'transfer_acl' in self._zone_config[config_key]: return self._zone_config[config_key]['transfer_acl'] return self._acl def _send_data(self, sock_fd, data): size = len(data) total_count = 0 while total_count < size: count = os.write(sock_fd, data[total_count:]) total_count += count def _send_message(self, sock_fd, msg, tsig_ctx=None): render = MessageRenderer() # As defined in RFC5936 section3.4, perform case-preserving name # compression for AXFR message. render.set_compress_mode(MessageRenderer.CASE_SENSITIVE) render.set_length_limit(XFROUT_MAX_MESSAGE_SIZE) # XXX Currently, python wrapper doesn't accept 'None' parameter in this case, # we should remove the if statement and use a universal interface later. if tsig_ctx is not None: msg.to_wire(render, tsig_ctx) else: msg.to_wire(render) header_len = struct.pack('H', socket.htons(render.get_length())) self._send_data(sock_fd, header_len) self._send_data(sock_fd, render.get_data()) def _reply_query_with_error_rcode(self, msg, sock_fd, rcode_): if not msg: return # query message is invalid. send nothing back. msg.make_response() msg.set_rcode(rcode_) self._send_message(sock_fd, msg, self._tsig_ctx) def _get_zone_soa(self, zone_name): '''Retrieve the SOA RR of the given zone. It returns a pair of RCODE and the SOA (in the form of RRset). On success RCODE is NOERROR and returned SOA is not None; on failure RCODE indicates the appropriate code in the context of xfr processing, and the returned SOA is None. ''' result, finder = self._datasrc_client.find_zone(zone_name) if result != DataSourceClient.SUCCESS: return (Rcode.NOTAUTH(), None) result, soa_rrset, _ = finder.find(zone_name, RRType.SOA()) if result != ZoneFinder.SUCCESS: return (Rcode.SERVFAIL(), None) # Especially for database-based zones, a working zone may be in # a broken state where it has more than one SOA RR. We proactively # check the condition and abort the xfr attempt if we identify it. if soa_rrset.get_rdata_count() != 1: return (Rcode.SERVFAIL(), None) return (Rcode.NOERROR(), soa_rrset) def __axfr_setup(self, zone_name): '''Setup a zone iterator for AXFR or AXFR-style IXFR. ''' try: # Note that we enable 'separate_rrs'. In xfr-out we need to # preserve as many things as possible (even if it's half broken) # stored in the zone. self._iterator = self._datasrc_client.get_iterator(zone_name, True) except isc.datasrc.Error: # If the current name server does not have authority for the # zone, xfrout can't serve for it, return rcode NOTAUTH. # Note: this exception can happen for other reasons. We should # update get_iterator() API so that we can distinguish "no such # zone" and other cases (#1373). For now we consider all these # cases as NOTAUTH. return Rcode.NOTAUTH() # If we are an authoritative name server for the zone, but fail # to find the zone's SOA record in datasource, xfrout can't # provide zone transfer for it. self._soa = self._iterator.get_soa() if self._soa is None or self._soa.get_rdata_count() != 1: return Rcode.SERVFAIL() return Rcode.NOERROR() def __ixfr_setup(self, request_msg, zone_name, zone_class): '''Setup a zone journal reader for IXFR. If the underlying data source does not know the requested range of zone differences it automatically falls back to AXFR-style IXFR by setting up a zone iterator instead of a journal reader. ''' # Check the authority section. Look for a SOA record with # the same name and class as the question. remote_soa = None for auth_rrset in request_msg.get_section(Message.SECTION_AUTHORITY): # Ignore data whose owner name is not the zone apex, and # ignore non-SOA or different class of records. if auth_rrset.get_name() != zone_name or \ auth_rrset.get_type() != RRType.SOA() or \ auth_rrset.get_class() != zone_class: continue if auth_rrset.get_rdata_count() != 1: logger.info(XFROUT_IXFR_MULTIPLE_SOA, format_addrinfo(self._remote)) return Rcode.FORMERR() remote_soa = auth_rrset if remote_soa is None: logger.info(XFROUT_IXFR_NO_SOA, format_addrinfo(self._remote)) return Rcode.FORMERR() # Retrieve the local SOA rcode, self._soa = self._get_zone_soa(zone_name) if rcode != Rcode.NOERROR(): return rcode # RFC1995 says "If an IXFR query with the same or newer version # number than that of the server is received, it is replied to with # a single SOA record of the server's current version, just as # in AXFR". The claim about AXFR is incorrect, but other than that, # we do as the RFC says. begin_serial = get_soa_serial(remote_soa.get_rdata()[0]) end_serial = get_soa_serial(self._soa.get_rdata()[0]) if begin_serial >= end_serial: # clear both iterator and jnl_reader to signal we won't do # iteration in response generation self._iterator = None self._jnl_reader = None logger.info(XFROUT_IXFR_UPTODATE, format_addrinfo(self._remote), format_zone_str(zone_name, zone_class), begin_serial, end_serial) return Rcode.NOERROR() # Set up the journal reader or fall back to AXFR-style IXFR try: code, self._jnl_reader = self._datasrc_client.get_journal_reader( zone_name, begin_serial.get_value(), end_serial.get_value()) except isc.datasrc.NotImplemented as ex: # The underlying data source doesn't support journaling. # Fall back to AXFR-style IXFR. logger.info(XFROUT_IXFR_NO_JOURNAL_SUPPORT, format_addrinfo(self._remote), format_zone_str(zone_name, zone_class)) return self.__axfr_setup(zone_name) if code == ZoneJournalReader.NO_SUCH_VERSION: logger.info(XFROUT_IXFR_NO_VERSION, format_addrinfo(self._remote), format_zone_str(zone_name, zone_class), begin_serial, end_serial) return self.__axfr_setup(zone_name) if code == ZoneJournalReader.NO_SUCH_ZONE: # this is quite unexpected as we know zone's SOA exists. # It might be a bug or the data source is somehow broken, # but it can still happen if someone has removed the zone # between these two operations. We treat it as NOTAUTH. logger.warn(XFROUT_IXFR_NO_ZONE, format_addrinfo(self._remote), format_zone_str(zone_name, zone_class)) return Rcode.NOTAUTH() # Use the reader as the iterator to generate the response. self._iterator = self._jnl_reader return Rcode.NOERROR() def _xfrout_setup(self, request_msg, zone_name, zone_class): '''Setup a context for xfr responses according to the request type. This method identifies the most appropriate data source for the request and set up a zone iterator or journal reader depending on whether the request is AXFR or IXFR. If it identifies any protocol level error it returns an RCODE other than NOERROR. ''' # Identify the data source for the requested zone and see if it has # SOA while initializing objects used for request processing later. # We should eventually generalize this so that we can choose the # appropriate data source from (possible) multiple candidates. # We should eventually take into account the RR class here. # For now, we hardcode a particular type (SQLite3-based), and only # consider that one. datasrc_config = '{ "database_file": "' + \ self._server.get_db_file() + '"}' self._datasrc_client = self.ClientClass('sqlite3', datasrc_config) if self._request_type == RRType.AXFR(): return self.__axfr_setup(zone_name) else: return self.__ixfr_setup(request_msg, zone_name, zone_class) def dns_xfrout_start(self, sock_fd, msg_query, quota_ok=True): rcode_, msg = self._parse_query_message(msg_query) #TODO. create query message and parse header if rcode_ is None: # Dropped by ACL return elif rcode_ == Rcode.NOTAUTH() or rcode_ == Rcode.REFUSED(): return self._reply_query_with_error_rcode(msg, sock_fd, rcode_) elif rcode_ != Rcode.NOERROR(): return self._reply_query_with_error_rcode(msg, sock_fd, Rcode.FORMERR()) elif not quota_ok: logger.warn(XFROUT_QUERY_QUOTA_EXCCEEDED, self._request_typestr, format_addrinfo(self._remote), self._server._max_transfers_out) return self._reply_query_with_error_rcode(msg, sock_fd, Rcode.REFUSED()) question = msg.get_question()[0] zone_name = question.get_name() zone_class = question.get_class() zone_str = format_zone_str(zone_name, zone_class) # for logging try: rcode_ = self._xfrout_setup(msg, zone_name, zone_class) except Exception as ex: logger.error(XFROUT_XFR_TRANSFER_CHECK_ERROR, self._request_typestr, format_addrinfo(self._remote), zone_str, ex) rcode_ = Rcode.SERVFAIL() if rcode_ != Rcode.NOERROR(): logger.info(XFROUT_XFR_TRANSFER_FAILED, self._request_typestr, format_addrinfo(self._remote), zone_str, rcode_) return self._reply_query_with_error_rcode(msg, sock_fd, rcode_) try: # increment Xfr starts by RRType if self._request_type == RRType.AXFR(): self._inc_axfr_running() else: self._inc_ixfr_running() logger.info(XFROUT_XFR_TRANSFER_STARTED, self._request_typestr, format_addrinfo(self._remote), zone_str) self._reply_xfrout_query(msg, sock_fd) except Exception as err: logger.error(XFROUT_XFR_TRANSFER_ERROR, self._request_typestr, format_addrinfo(self._remote), zone_str, err) finally: # decrement Xfr starts by RRType if self._request_type == RRType.AXFR(): self._dec_axfr_running() else: self._dec_ixfr_running() # count done Xfr requests by each zone name self._counter_xfrreqdone(zone_name.to_text()) logger.info(XFROUT_XFR_TRANSFER_DONE, self._request_typestr, format_addrinfo(self._remote), zone_str) def _clear_message(self, msg): qid = msg.get_qid() opcode = msg.get_opcode() rcode = msg.get_rcode() msg.clear(Message.RENDER) msg.set_qid(qid) msg.set_opcode(opcode) msg.set_rcode(rcode) msg.set_header_flag(Message.HEADERFLAG_AA) msg.set_header_flag(Message.HEADERFLAG_QR) return msg def _send_message_with_last_soa(self, msg, sock_fd, rrset_soa, message_upper_len): '''Add the SOA record to the end of message. If it would exceed the maximum allowable size of a message, a new message will be created to send out the last SOA. We assume a message with a single SOA can always fit the buffer with or without TSIG. In theory this could be wrong if TSIG is stupidly large, but in practice this assumption should be reasonable. ''' if message_upper_len + get_rrset_len(rrset_soa) > \ XFROUT_MAX_MESSAGE_SIZE: self._send_message(sock_fd, msg, self._tsig_ctx) msg = self._clear_message(msg) msg.add_rrset(Message.SECTION_ANSWER, rrset_soa) self._send_message(sock_fd, msg, self._tsig_ctx) def _reply_xfrout_query(self, msg, sock_fd): msg.make_response() msg.set_header_flag(Message.HEADERFLAG_AA) # Reserved space for the fixed header size, the size of the question # section, and TSIG size (when included). The size of the question # section is the sum of the qname length and the size of the # fixed-length fields (type and class, 2 bytes each). message_upper_len = XFROUT_DNS_HEADER_SIZE + \ msg.get_question()[0].get_name().get_length() + 4 + \ self._tsig_len # If the iterator is None, we are responding to IXFR with a single # SOA RR. if self._iterator is None: self._send_message_with_last_soa(msg, sock_fd, self._soa, message_upper_len) return # Add the beginning SOA msg.add_rrset(Message.SECTION_ANSWER, self._soa) message_upper_len += get_rrset_len(self._soa) # Add the rest of the zone/diff contets for rrset in self._iterator: # Check if xfrout is shutdown if self._server._shutdown_event.is_set(): logger.info(XFROUT_STOPPING) return # For AXFR (or AXFR-style IXFR), in which case _jnl_reader is None, # we should skip SOAs from the iterator. if self._jnl_reader is None and rrset.get_type() == RRType.SOA(): continue # We calculate the maximum size of the RRset (i.e. the # size without compression) and use that to see if we # may have reached the limit rrset_len = get_rrset_len(rrset) if message_upper_len + rrset_len <= XFROUT_MAX_MESSAGE_SIZE: msg.add_rrset(Message.SECTION_ANSWER, rrset) message_upper_len += rrset_len continue # RR would not fit. If there are other RRs in the buffer, send # them now and leave this RR to the next message. self._send_message(sock_fd, msg, self._tsig_ctx) # Create a new message and reserve space for the carried-over # RR (and TSIG space in case it's to be TSIG signed) msg = self._clear_message(msg) message_upper_len = XFROUT_DNS_HEADER_SIZE + rrset_len + \ self._tsig_len # If this RR overflows the buffer all by itself, fail. In theory # some RRs might fit in a TCP message when compressed even if they # do not fit when uncompressed, but surely we don't want to send # such monstrosities to an unsuspecting slave. if message_upper_len > XFROUT_MAX_MESSAGE_SIZE: raise XfroutSessionError('RR too large for zone transfer (' + str(rrset_len) + ' bytes)') # Add the RRset to the new message msg.add_rrset(Message.SECTION_ANSWER, rrset) # Add and send the trailing SOA self._send_message_with_last_soa(msg, sock_fd, self._soa, message_upper_len) class UnixSockServer(socketserver_mixin.NoPollMixIn, ThreadingUnixStreamServer): '''The unix domain socket server which accept xfr query sent from auth server.''' def __init__(self, sock_file, handle_class, shutdown_event, config_data, cc, **counters): self._remove_unused_sock_file(sock_file) self._sock_file = sock_file socketserver_mixin.NoPollMixIn.__init__(self) ThreadingUnixStreamServer.__init__(self, sock_file, handle_class) self._shutdown_event = shutdown_event self._write_sock, self._read_sock = socket.socketpair() self._common_init() self._cc = cc self.update_config_data(config_data) # handlers for statistics use self._counters = counters def _common_init(self): '''Initialization shared with the mock server class used for tests''' self._lock = threading.Lock() self._transfers_counter = 0 self._zone_config = {} self._acl = None # this will be initialized in update_config_data() def _receive_query_message(self, sock): ''' receive request message from sock''' # receive data length data_len = sock.recv(2) if not data_len: return None msg_len = struct.unpack('!H', data_len)[0] # receive data recv_size = 0 msgdata = b'' while recv_size < msg_len: data = sock.recv(msg_len - recv_size) if not data: return None recv_size += len(data) msgdata += data return msgdata def handle_request(self): ''' Enable server handle a request until shutdown or auth is closed.''' try: request, client_address = self.get_request() except socket.error: logger.error(XFROUT_FETCH_REQUEST_ERROR) return self._select_loop(request) def _select_loop(self, request_sock): '''Main loop for a single session between xfrout and auth. This is a dedicated subroutine of handle_request(), but is defined as a separate "protected" method for the convenience of tests. ''' # Check self._shutdown_event to ensure the real shutdown comes. # Linux could trigger a spurious readable event on the _read_sock # due to a bug, so we need perform a double check. while not self._shutdown_event.is_set(): # Check if xfrout is shutdown try: (rlist, wlist, xlist) = select.select([self._read_sock, request_sock], [], []) except select.error as e: if e.args[0] == errno.EINTR: (rlist, wlist, xlist) = ([], [], []) continue else: logger.error(XFROUT_SOCKET_SELECT_ERROR, e) break # self.server._shutdown_event will be set by now, if it is not a # false alarm if self._read_sock in rlist: continue try: if not self.process_request(request_sock): break except Exception as pre: logger.error(XFROUT_PROCESS_REQUEST_ERROR, pre) break def _handle_request_noblock(self): """Override the function _handle_request_noblock(), it creates a new thread to handle requests for each auth""" td = threading.Thread(target=self.handle_request) td.setDaemon(True) td.start() def process_request(self, request): """Receive socket fd and query message from auth, then start a new thread to process the request. Return: True if everything is okay; otherwise False, in which case the calling thread will terminate. """ sock_fd = recv_fd(request.fileno()) if sock_fd < 0: logger.warn(XFROUT_RECEIVE_FILE_DESCRIPTOR_ERROR) return False # receive request msg. If it fails we simply terminate the thread; # it might be possible to recover from this state, but it's more likely # that auth and xfrout are in inconsistent states. So it will make # more sense to restart in a new session. request_data = self._receive_query_message(request) if request_data is None: # The specific exception type doesn't matter so we use session # error. raise XfroutSessionError('Failed to get complete xfr request') t = threading.Thread(target=self.finish_request, args=(sock_fd, request_data)) if self.daemon_threads: t.daemon = True t.start() return True def _guess_remote(self, sock_fd): """Guess remote address and port of the socket. The sock_fd must be a file descriptor of a socket. This method retuns a 3-tuple consisting of address family, socket type, and a 2-tuple with the address (string) and port (int). """ # This uses a trick. If the socket is IPv4 in reality and we pretend # it to be IPv6, it returns IPv4 address anyway. This doesn't seem # to care about the SOCK_STREAM parameter at all (which it really is, # except for testing) if socket.has_ipv6: sock_domain = socket.AF_INET6 else: # To make it work even on hosts without IPv6 support # (Any idea how to simulate this in test?) sock_domain = socket.AF_INET sock = socket.fromfd(sock_fd, sock_domain, socket.SOCK_STREAM) peer = sock.getpeername() sock.close() # Identify the correct socket family. Due to the above "trick", # we cannot simply use sock.family. family = socket.AF_INET6 try: socket.inet_pton(socket.AF_INET6, peer[0]) except socket.error: family = socket.AF_INET return (family, socket.SOCK_STREAM, peer) def finish_request(self, sock_fd, request_data): '''Finish one request by instantiating RequestHandlerClass. This is an entry point of a separate thread spawned in UnixSockServer.process_request(). This method creates a XfroutSession object. ''' self._lock.acquire() acl = self._acl zone_config = self._zone_config self._lock.release() self.RequestHandlerClass(sock_fd, request_data, self, isc.server_common.tsig_keyring.get_keyring(), self._guess_remote(sock_fd), acl, zone_config, **self._counters) def _remove_unused_sock_file(self, sock_file): '''Try to remove the socket file. If the file is being used by one running xfrout process, exit from python. If it's not a socket file or nobody is listening , it will be removed. If it can't be removed, exit from python. ''' if self._sock_file_in_use(sock_file): logger.error(XFROUT_UNIX_SOCKET_FILE_IN_USE, sock_file) sys.exit(0) else: if not os.path.exists(sock_file): return try: os.unlink(sock_file) except OSError as err: logger.error(XFROUT_REMOVE_OLD_UNIX_SOCKET_FILE_ERROR, sock_file, str(err)) sys.exit(0) def _sock_file_in_use(self, sock_file): '''Check whether the socket file 'sock_file' exists and is being used by one running xfrout process. If it is, return True, or else return False. ''' try: sock = socket.socket(socket.AF_UNIX) sock.connect(sock_file) except socket.error as err: sock.close() return False else: sock.close() return True def shutdown(self): self._write_sock.send(b"shutdown") #terminate the xfrout session thread super().shutdown() # call the shutdown() of class socketserver_mixin.NoPollMixIn try: os.unlink(self._sock_file) except Exception as e: logger.error(XFROUT_REMOVE_UNIX_SOCKET_FILE_ERROR, self._sock_file, str(e)) def update_config_data(self, new_config): '''Apply the new config setting of xfrout module. ''' self._lock.acquire() try: logger.info(XFROUT_NEW_CONFIG) new_acl = self._acl if 'transfer_acl' in new_config: try: new_acl = REQUEST_LOADER.load(new_config['transfer_acl']) except LoaderError as e: raise XfroutConfigError('Failed to parse transfer_acl: ' + str(e)) new_zone_config = self._zone_config zconfig_data = new_config.get('zone_config') if zconfig_data is not None: new_zone_config = self.__create_zone_config(zconfig_data) self._acl = new_acl self._zone_config = new_zone_config self._max_transfers_out = new_config.get('transfers_out') except Exception as e: self._lock.release() raise e self._lock.release() logger.info(XFROUT_NEW_CONFIG_DONE) def __create_zone_config(self, zone_config_list): new_config = {} for zconf in zone_config_list: # convert the class, origin (name) pair. First build pydnspp # object to reject invalid input. zclass_str = zconf.get('class') if zclass_str is None: #zclass_str = 'IN' # temporary zclass_str = self._cc.get_default_value('zone_config/class') zclass = RRClass(zclass_str) zorigin = Name(zconf['origin'], True) config_key = (zclass.to_text(), zorigin.to_text()) # reject duplicate config if config_key in new_config: raise XfroutConfigError('Duplicate zone_config for ' + str(zorigin) + '/' + str(zclass)) # create a new config entry, build any given (and known) config new_config[config_key] = {} if 'transfer_acl' in zconf: try: new_config[config_key]['transfer_acl'] = \ REQUEST_LOADER.load(zconf['transfer_acl']) except LoaderError as e: raise XfroutConfigError('Failed to parse transfer_acl ' + 'for ' + zorigin.to_text() + '/' + zclass_str + ': ' + str(e)) return new_config def get_db_file(self): file, is_default = self._cc.get_remote_config_value("Auth", "database_file") # this too should be unnecessary, but currently the # 'from build' override isn't stored in the config # (and we don't have indirect python access to datasources yet) if is_default and "B10_FROM_BUILD" in os.environ: file = os.environ["B10_FROM_BUILD"] + os.sep + "bind10_zones.sqlite3" return file def increase_transfers_counter(self): '''Return False, if counter + 1 > max_transfers_out, or else return True ''' ret = False self._lock.acquire() if self._transfers_counter < self._max_transfers_out: self._transfers_counter += 1 ret = True self._lock.release() return ret def decrease_transfers_counter(self): self._lock.acquire() self._transfers_counter -= 1 self._lock.release() class XfroutCounter: """A class for handling all statistics counters of Xfrout. In this class, the structure of per-zone counters is assumed to be like this: zones/example.com./notifyoutv4 zones/example.com./notifyoutv6 zones/example.com./xfrrej zones/example.com./xfrreqdone ixfr_running axfr_running """ # '_SERVER_' is a special zone name representing an entire # count. It doesn't mean a specific zone, but it means an # entire count in the server. entire_server = '_SERVER_' # zone names are contained under this dirname in the spec file. perzone_prefix = 'zones' def __init__(self, statistics_spec): self._statistics_spec = statistics_spec # holding statistics data for Xfrout module self._statistics_data = {} self._counters_for_xfroutsession = {} self._counters_for_notifyout = {} self._xfrrunning_names = [ n for n in isc.config.spec_name_list\ (self._statistics_spec) \ if n.find('xfr_running') == 1 ] self._lock = threading.RLock() self._create_perzone_incrementers() self._create_xfrrunning_incdecrementers() def get_statistics(self): """Calculates an entire server counts, and returns statistics data format to send out the stats module including each counter. If there is no counts, then it returns an empty dictionary. Locks the thread because it is considered to be invoked by a multi-threading caller.""" # If self._statistics_data contains nothing of zone name, it # returns an empty dict. if len(self._statistics_data) == 0: return {} # for per-zone counter zones = {} zones = self._statistics_data[self.perzone_prefix] # Start calculation for '_SERVER_' counts attrs = self._get_default_statistics_data()[self.perzone_prefix][self.entire_server] statistics_data = {self.perzone_prefix: {}} for attr in attrs: sum_ = 0 for name in zones: if name == self.entire_server: continue if attr in zones[name]: if name not in statistics_data[self.perzone_prefix]: statistics_data[self.perzone_prefix][name] = {} statistics_data[self.perzone_prefix][name].update( {attr: zones[name][attr]} ) sum_ += zones[name][attr] if sum_ > 0: if self.entire_server not in statistics_data[self.perzone_prefix]: statistics_data[self.perzone_prefix][self.entire_server] = {} statistics_data[self.perzone_prefix][self.entire_server]\ .update({attr:sum_}) # for xfrrunning incrementer/decrementer for name in self._xfrrunning_names: if name in self._statistics_data: statistics_data[name] = self._statistics_data[name] return statistics_data def _get_default_statistics_data(self): """Returns default statistics data from the spec file""" statistics_data = {} for id_ in isc.config.spec_name_list(self._statistics_spec): spec = isc.config.find_spec_part(self._statistics_spec, id_) statistics_data.update({id_: spec['item_default']}) return statistics_data def _create_perzone_incrementers(self): """Creates increment method of each per-zone counter based on the spec file. Incrementer can be accessed by name "inc_${item_name}".Incrementers are passed to the XfroutSession and NotifyOut class as counter handlers.""" # add a new element under the named_set item for the zone zones_spec = isc.config.find_spec_part( self._statistics_spec, self.perzone_prefix) item_list = isc.config.spec_name_list(\ zones_spec['named_set_item_spec']['map_item_spec']) # can be accessed by the name 'inc_xxx' for item in item_list: def __perzone_incrementer(zone_name, counter_name=item, step=1): """A per-zone incrementer for counter_name. Locks the thread because it is considered to be invoked by a multi-threading caller.""" with self._lock: self._add_perzone_counter(zone_name) self._statistics_data[self.perzone_prefix][zone_name][counter_name] += step if 'notifyout' in item: self._counters_for_notifyout['counter_%s' % item] \ = __perzone_incrementer else: self._counters_for_xfroutsession['counter_%s' % item] \ = __perzone_incrementer def _create_xfrrunning_incdecrementers(self): """Creates increment/decrement method of (a|i)xfr_running based on the spec file. Incrementer can be accessed by name "inc_${item_name}". Decrementer can be accessed by name "dec_${item_name}". Both of them are passed to the XfroutSession as counter handlers.""" # can be accessed by the name 'inc_xxx' or 'dec_xxx' for item in self._xfrrunning_names: def __xfrrunning_incrementer(counter_name=item, step=1): """A incrementer for axfr or ixfr running. Locks the thread because it is considered to be invoked by a multi-threading caller.""" with self._lock: self._add_xfrrunning_counter(counter_name) self._statistics_data[counter_name] += step def __xfrrunning_decrementer(counter_name=item, step=-1): """A decrementer for axfr or ixfr running. Locks the thread because it is considered to be invoked by a multi-threading caller.""" with self._lock: self._statistics_data[counter_name] += step self._counters_for_xfroutsession['inc_%s' % item] \ = __xfrrunning_incrementer self._counters_for_xfroutsession['dec_%s' % item] \ = __xfrrunning_decrementer def get_counters_for_xfroutsession(self): """Returns counters, incrementers, and decrementers to be passed to XfroutSession/UnixSockServer class.""" return self._counters_for_xfroutsession def get_counters_for_notifyout(self): """Returns counters handlers to be passed to NotifyOut class.""" return self._counters_for_notifyout def _add_perzone_counter(self, zone): """Adds a named_set-type counter for each zone name.""" try: self._statistics_data[self.perzone_prefix][zone] except KeyError: # add a new element under the named_set item for the zone map_spec = isc.config.find_spec_part( self._statistics_spec, '%s/%s' % \ (self.perzone_prefix, zone))['map_item_spec'] id_list = isc.config.spec_name_list(map_spec) for id_ in id_list: spec = isc.config.find_spec_part(map_spec, id_) isc.cc.data.set(self._statistics_data, '%s/%s/%s' % \ (self.perzone_prefix, zone, id_), spec['item_default']) def _add_xfrrunning_counter(self, counter_name): """Adds a counter for counting (a|i)xfr_running""" try: self._statistics_data[counter_name] except KeyError: # examines the names of xfer running for n in self._xfrrunning_names: spec = isc.config.find_spec_part(self._statistics_spec, n) isc.cc.data.set(self._statistics_data, n, \ spec['item_default']) class XfroutServer: def __init__(self): self._unix_socket_server = None self._listen_sock_file = UNIX_SOCKET_FILE self._shutdown_event = threading.Event() self._cc = isc.config.ModuleCCSession(SPECFILE_LOCATION, self.config_handler, self.command_handler) self._config_data = self._cc.get_full_config() self._counter = XfroutCounter( self._cc.get_module_spec().get_statistics_spec()) self._cc.start() self._cc.add_remote_config(AUTH_SPECFILE_LOCATION) isc.server_common.tsig_keyring.init_keyring(self._cc) self._start_xfr_query_listener() self._start_notifier() def _start_xfr_query_listener(self): '''Start a new thread to accept xfr query. ''' self._unix_socket_server = UnixSockServer( self._listen_sock_file, XfroutSession, self._shutdown_event, self._config_data, self._cc, **self._counter.get_counters_for_xfroutsession() ) listener = threading.Thread(target=self._unix_socket_server.serve_forever) listener.start() def _start_notifier(self): datasrc = self._unix_socket_server.get_db_file() self._notifier = notify_out.NotifyOut( datasrc, **self._counter.get_counters_for_notifyout() ) if 'also_notify' in self._config_data: for slave in self._config_data['also_notify']: self._notifier.add_slave(slave['address'], slave['port']) self._notifier.dispatcher() def send_notify(self, zone_name, zone_class): return self._notifier.send_notify(zone_name, zone_class) def config_handler(self, new_config): '''Update config data. TODO. Do error check''' answer = create_answer(0) for key in new_config: if key not in self._config_data: answer = create_answer(1, "Unknown config data: " + str(key)) continue self._config_data[key] = new_config[key] if self._unix_socket_server: try: self._unix_socket_server.update_config_data(self._config_data) except Exception as e: answer = create_answer(1, "Failed to handle new configuration: " + str(e)) return answer def shutdown(self): ''' shutdown the xfrout process. The thread which is doing zone transfer-out should be terminated. ''' global xfrout_server xfrout_server = None #Avoid shutdown is called twice self._cc.send_stopping() self._shutdown_event.set() self._notifier.shutdown() if self._unix_socket_server: self._unix_socket_server.shutdown() self._wait_for_threads() def _wait_for_threads(self): # Wait for all threads to terminate. this is a call that is only used # in shutdown(), but it has its own method, so we can test shutdown # without involving thread operations (the test would override this # method) main_thread = threading.currentThread() for th in threading.enumerate(): if th is main_thread: continue th.join() def command_handler(self, cmd, args): if cmd == "shutdown": logger.info(XFROUT_RECEIVED_SHUTDOWN_COMMAND) self.shutdown() answer = create_answer(0) elif cmd == "notify": zone_name = args.get('zone_name') zone_class = args.get('zone_class') if not zone_class: zone_class = str(RRClass.IN()) if zone_name: logger.info(XFROUT_NOTIFY_COMMAND, zone_name, zone_class) if self.send_notify(zone_name, zone_class): answer = create_answer(0) else: zonestr = notify_out.format_zone_str(Name(zone_name), zone_class) answer = create_answer(1, "Unknown zone: " + zonestr) else: answer = create_answer(1, "Bad command parameter:" + str(args)) # return statistics data to the stats daemon elif cmd == "getstats": # The log level is here set to debug in order to avoid # that a log becomes too verbose. Because the b10-stats # daemon is periodically asking to the b10-xfrout daemon. logger.debug(DBG_XFROUT_TRACE, \ XFROUT_RECEIVED_GETSTATS_COMMAND) answer = create_answer(0, self._counter.get_statistics()) else: answer = create_answer(1, "Unknown command:" + str(cmd)) return answer def run(self): '''Get and process all commands sent from cfgmgr or other modules. ''' logger.debug(DBG_PROCESS, XFROUT_STARTED) while not self._shutdown_event.is_set(): self._cc.check_command(False) xfrout_server = None def signal_handler(signal, frame): if xfrout_server: xfrout_server.shutdown() sys.exit(0) def set_signal_handler(): signal.signal(signal.SIGTERM, signal_handler) signal.signal(signal.SIGINT, signal_handler) def set_cmd_options(parser): parser.add_option("-v", "--verbose", dest="verbose", action="store_true", help="display more about what is going on") if '__main__' == __name__: try: parser = OptionParser() set_cmd_options(parser) (options, args) = parser.parse_args() VERBOSE_MODE = options.verbose set_signal_handler() xfrout_server = XfroutServer() xfrout_server.run() except KeyboardInterrupt: logger.info(XFROUT_STOPPED_BY_KEYBOARD) except SessionError as e: logger.error(XFROUT_CC_SESSION_ERROR, str(e)) except ModuleCCSessionError as e: logger.error(XFROUT_MODULECC_SESSION_ERROR, str(e)) except XfroutConfigError as e: logger.error(XFROUT_CONFIG_ERROR, str(e)) except SessionTimeout as e: logger.error(XFROUT_CC_SESSION_TIMEOUT_ERROR) if xfrout_server: xfrout_server.shutdown() logger.info(XFROUT_EXITING)