Adding upstream version 5.6.0.upstream/5.6.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 888 insertions, 0 deletions

diff --git a/tests/integration/deckard/pydnstest/scenario.py b/tests/integration/deckard/pydnstest/scenario.py
new file mode 100644
index 0000000..9ef318c
--- /dev/null
+++ b/tests/integration/deckard/pydnstest/scenario.py
@@ -0,0 +1,888 @@
+from abc import ABC
+import binascii
+import calendar
+from datetime import datetime
+import logging
+import os  # requires posix
+import random
+import socket
+import struct
+import time
+from typing import Optional
+
+import dns.dnssec
+import dns.message
+import dns.name
+import dns.rcode
+import dns.rrset
+import dns.tsigkeyring
+
+import pydnstest.augwrap
+import pydnstest.matchpart
+import pydnstest.mock_client
+
+
+def str2bool(v):
+    """ Return conversion of JSON-ish string value to boolean. """
+    return v.lower() in ('yes', 'true', 'on', '1')
+
+
+# Global statistics
+g_rtt = 0.0
+g_nqueries = 0
+
+
+class DNSBlob(ABC):
+    def to_wire(self) -> bytes:
+        raise NotImplementedError
+
+    def __str__(self) -> str:
+        return '<DNSBlob>'
+
+
+class DNSMessage(DNSBlob):
+    def __init__(self, message: dns.message.Message) -> None:
+        assert message is not None
+        self.message = message
+
+    def to_wire(self) -> bytes:
+        return self.message.to_wire(max_size=65535)
+
+    def __str__(self) -> str:
+        return str(self.message)
+
+
+class DNSReply(DNSMessage):
+    def __init__(
+                self,
+                message: dns.message.Message,
+                query: Optional[dns.message.Message] = None,
+                copy_id: bool = False,
+                copy_query: bool = False
+            ) -> None:
+        super().__init__(message)
+        if copy_id or copy_query:
+            if query is None:
+                raise ValueError("query must be provided to adjust copy_id/copy_query")
+            self.adjust_reply(query, copy_id, copy_query)
+
+    def adjust_reply(
+                self,
+                query: dns.message.Message,
+                copy_id: bool = True,
+                copy_query: bool = True
+            ) -> None:
+        answer = dns.message.from_wire(self.message.to_wire(),
+                                       xfr=self.message.xfr,
+                                       one_rr_per_rrset=True)
+        answer.use_edns(query.edns, query.ednsflags, options=self.message.options)
+        if copy_id:
+            answer.id = query.id
+            # Copy letter-case if the template has QD
+            if answer.question:
+                answer.question[0].name = query.question[0].name
+        if copy_query:
+            answer.question = query.question
+        # Re-set, as the EDNS might have reset the ext-rcode
+        answer.set_rcode(self.message.rcode())
+
+        # sanity check: adjusted answer should be almost the same
+        assert len(answer.answer) == len(self.message.answer)
+        assert len(answer.authority) == len(self.message.authority)
+        assert len(answer.additional) == len(self.message.additional)
+        self.message = answer
+
+
+class DNSReplyRaw(DNSBlob):
+    def __init__(
+                self,
+                wire: bytes,
+                query: Optional[dns.message.Message] = None,
+                copy_id: bool = False
+            ) -> None:
+        assert wire is not None
+        self.wire = wire
+        if copy_id:
+            if query is None:
+                raise ValueError("query must be provided to adjust copy_id")
+            self.adjust_reply(query, copy_id)
+
+    def adjust_reply(
+                self,
+                query: dns.message.Message,
+                raw_id: bool = True
+            ) -> None:
+        if raw_id:
+            if len(self.wire) < 2:
+                raise ValueError(
+                    'wire data must contain at least 2 bytes to adjust query id')
+            raw_answer = bytearray(self.wire)
+            struct.pack_into('!H', raw_answer, 0, query.id)
+            self.wire = bytes(raw_answer)
+
+    def to_wire(self) -> bytes:
+        return self.wire
+
+    def __str__(self) -> str:
+        return '<DNSReplyRaw>'
+
+
+class DNSReplyServfail(DNSMessage):
+    def __init__(self, query: dns.message.Message) -> None:
+        message = dns.message.make_response(query)
+        message.set_rcode(dns.rcode.SERVFAIL)
+        super().__init__(message)
+
+
+class Entry:
+    """
+    Data entry represents scripted message and extra metadata,
+    notably match criteria and reply adjustments.
+    """
+
+    # Globals
+    default_ttl = 3600
+    default_cls = 'IN'
+    default_rc = 'NOERROR'
+
+    def __init__(self, node):
+        """ Initialize data entry. """
+        self.node = node
+        self.origin = '.'
+        self.message = dns.message.Message()
+        self.message.use_edns(edns=0, payload=4096)
+        self.fired = 0
+
+        # RAW
+        self.raw_data = self.process_raw()
+
+        # MATCH
+        self.match_fields = self.process_match()
+
+        # FLAGS (old alias REPLY)
+        self.process_reply_line()
+
+        # ADJUST
+        self.adjust_fields = {m.value for m in node.match("/adjust")}
+
+        # MANDATORY
+        try:
+            self.mandatory = list(node.match("/mandatory"))[0]
+        except (KeyError, IndexError):
+            self.mandatory = None
+
+        # TSIG
+        self.process_tsig()
+
+        # SECTIONS & RECORDS
+        self.sections = self.process_sections()
+
+    def process_raw(self):
+        try:
+            return binascii.unhexlify(self.node["/raw"].value)
+        except KeyError:
+            return None
+
+    def process_match(self):
+        try:
+            self.node["/match_present"]
+        except KeyError:
+            return None
+
+        fields = set(m.value for m in self.node.match("/match"))
+
+        if 'all' in fields:
+            fields.remove("all")
+            fields |= set(["opcode", "qtype", "qname", "flags",
+                           "rcode", "answer", "authority", "additional"])
+
+        if 'question' in fields:
+            fields.remove("question")
+            fields |= set(["qtype", "qname"])
+
+        return fields
+
+    def process_reply_line(self):
+        """Extracts flags, rcode and opcode from given node and adjust dns message accordingly"""
+        fields = [f.value for f in self.node.match("/reply")]
+        if 'DO' in fields:
+            self.message.want_dnssec(True)
+        opcode = self.get_opcode(fields)
+        rcode = self.get_rcode(fields)
+        self.message.flags = self.get_flags(fields)
+        if rcode is not None:
+            self.message.set_rcode(rcode)
+        if opcode is not None:
+            self.message.set_opcode(opcode)
+
+    def process_tsig(self):
+        try:
+            tsig = list(self.node.match("/tsig"))[0]
+            tsig_keyname = tsig["/keyname"].value
+            tsig_secret = tsig["/secret"].value
+            keyring = dns.tsigkeyring.from_text({tsig_keyname: tsig_secret})
+            self.message.use_tsig(keyring=keyring, keyname=tsig_keyname)
+        except (KeyError, IndexError):
+            pass
+
+    def process_sections(self):
+        sections = set()
+        for section in self.node.match("/section/*"):
+            section_name = os.path.basename(section.path)
+            sections.add(section_name)
+            for record in section.match("/record"):
+                owner = record['/domain'].value
+                if not owner.endswith("."):
+                    owner += self.origin
+                try:
+                    ttl = dns.ttl.from_text(record['/ttl'].value)
+                except KeyError:
+                    ttl = self.default_ttl
+                try:
+                    rdclass = dns.rdataclass.from_text(record['/class'].value)
+                except KeyError:
+                    rdclass = dns.rdataclass.from_text(self.default_cls)
+                rdtype = dns.rdatatype.from_text(record['/type'].value)
+                rr = dns.rrset.from_text(owner, ttl, rdclass, rdtype)
+                if section_name != "question":
+                    rd = record['/data'].value.split()
+                    if rd:
+                        if rdtype == dns.rdatatype.DS:
+                            rd[1] = '{}'.format(dns.dnssec.algorithm_from_text(rd[1]))
+                        rd = dns.rdata.from_text(rr.rdclass, rr.rdtype, ' '.join(
+                            rd), origin=dns.name.from_text(self.origin), relativize=False)
+                    rr.add(rd)
+                if section_name == 'question':
+                    if rr.rdtype == dns.rdatatype.AXFR:
+                        self.message.xfr = True
+                    self.message.question.append(rr)
+                elif section_name == 'answer':
+                    self.message.answer.append(rr)
+                elif section_name == 'authority':
+                    self.message.authority.append(rr)
+                elif section_name == 'additional':
+                    self.message.additional.append(rr)
+        return sections
+
+    def __str__(self):
+        txt = 'ENTRY_BEGIN\n'
+        if self.raw_data is None:
+            txt += 'MATCH {0}\n'.format(' '.join(self.match_fields))
+        txt += 'ADJUST {0}\n'.format(' '.join(self.adjust_fields))
+        txt += 'REPLY {rcode} {flags}\n'.format(
+            rcode=dns.rcode.to_text(self.message.rcode()),
+            flags=' '.join([dns.flags.to_text(self.message.flags),
+                            dns.flags.edns_to_text(self.message.ednsflags)])
+        )
+        for sect_name in ['question', 'answer', 'authority', 'additional']:
+            sect = getattr(self.message, sect_name)
+            if not sect:
+                continue
+            txt += 'SECTION {n}\n'.format(n=sect_name.upper())
+            for rr in sect:
+                txt += str(rr)
+                txt += '\n'
+        if self.raw_data is not None:
+            txt += 'RAW\n'
+            if self.raw_data:
+                txt += binascii.hexlify(self.raw_data)
+            else:
+                txt += 'NULL'
+            txt += '\n'
+        txt += 'ENTRY_END\n'
+        return txt
+
+    @classmethod
+    def get_flags(cls, fields):
+        """From `fields` extracts and returns flags"""
+        flags = []
+        for code in fields:
+            try:
+                dns.flags.from_text(code)  # throws KeyError on failure
+                flags.append(code)
+            except KeyError:
+                pass
+        return dns.flags.from_text(' '.join(flags))
+
+    @classmethod
+    def get_rcode(cls, fields):
+        """
+        From `fields` extracts and returns rcode.
+        Throws `ValueError` if there are more then one rcodes
+        """
+        rcodes = []
+        for code in fields:
+            try:
+                rcodes.append(dns.rcode.from_text(code))
+            except dns.rcode.UnknownRcode:
+                pass
+        if len(rcodes) > 1:
+            raise ValueError("Parse failed, too many rcode values.", rcodes)
+        if not rcodes:
+            return None
+        return rcodes[0]
+
+    @classmethod
+    def get_opcode(cls, fields):
+        """
+        From `fields` extracts and returns opcode.
+        Throws `ValueError` if there are more then one opcodes
+        """
+        opcodes = []
+        for code in fields:
+            try:
+                opcodes.append(dns.opcode.from_text(code))
+            except dns.opcode.UnknownOpcode:
+                pass
+        if len(opcodes) > 1:
+            raise ValueError("Parse failed, too many opcode values.")
+        if not opcodes:
+            return None
+        return opcodes[0]
+
+    def match(self, msg):
+        """ Compare scripted reply to given message based on match criteria. """
+        for code in self.match_fields:
+            try:
+                pydnstest.matchpart.match_part(self.message, msg, code)
+            except pydnstest.matchpart.DataMismatch as ex:
+                errstr = '%s in the response:\n%s' % (str(ex), msg.to_text())
+                # TODO: cisla radku
+                raise ValueError("%s, \"%s\": %s" % (self.node.span, code, errstr)) from None
+
+    def cmp_raw(self, raw_value):
+        assert self.raw_data is not None
+        expected = None
+        if self.raw_data is not None:
+            expected = binascii.hexlify(self.raw_data)
+        got = None
+        if raw_value is not None:
+            got = binascii.hexlify(raw_value)
+        if expected != got:
+            raise ValueError("raw message comparsion failed: expected %s got %s" % (expected, got))
+
+    def reply(self, query) -> Optional[DNSBlob]:
+        if 'do_not_answer' in self.adjust_fields:
+            return None
+        if self.raw_data is not None:
+            raw_id = 'raw_id' in self.adjust_fields
+            assert self.raw_data is not None
+            return DNSReplyRaw(self.raw_data, query, raw_id)
+        copy_id = 'copy_id' in self.adjust_fields
+        copy_query = 'copy_query' in self.adjust_fields
+        return DNSReply(self.message, query, copy_id, copy_query)
+
+    def set_edns(self, fields):
+        """ Set EDNS version and bufsize. """
+        version = 0
+        bufsize = 4096
+        if fields and fields[0].isdigit():
+            version = int(fields.pop(0))
+        if fields and fields[0].isdigit():
+            bufsize = int(fields.pop(0))
+        if bufsize == 0:
+            self.message.use_edns(False)
+            return
+        opts = []
+        for v in fields:
+            k, v = tuple(v.split('=')) if '=' in v else (v, True)
+            if k.lower() == 'nsid':
+                opts.append(dns.edns.GenericOption(dns.edns.NSID, '' if v is True else v))
+            if k.lower() == 'subnet':
+                net = v.split('/')
+                subnet_addr = net[0]
+                family = socket.AF_INET6 if ':' in subnet_addr else socket.AF_INET
+                addr = socket.inet_pton(family, subnet_addr)
+                prefix = len(addr) * 8
+                if len(net) > 1:
+                    prefix = int(net[1])
+                addr = addr[0: (prefix + 7) / 8]
+                if prefix % 8 != 0:  # Mask the last byte
+                    addr = addr[:-1] + chr(ord(addr[-1]) & 0xFF << (8 - prefix % 8))
+                opts.append(dns.edns.GenericOption(8, struct.pack(
+                    "!HBB", 1 if family == socket.AF_INET else 2, prefix, 0) + addr))
+        self.message.use_edns(edns=version, payload=bufsize, options=opts)
+
+
+class Range:
+    """
+    Range represents a set of scripted queries valid for given step range.
+    """
+    log = logging.getLogger('pydnstest.scenario.Range')
+
+    def __init__(self, node):
+        """ Initialize reply range. """
+        self.node = node
+        self.a = int(node['/from'].value)
+        self.b = int(node['/to'].value)
+        assert self.a <= self.b
+
+        address = node["/address"].value
+        self.addresses = {address} if address is not None else set()
+        self.addresses |= {a.value for a in node.match("/address/*")}
+        self.stored = [Entry(n) for n in node.match("/entry")]
+        self.args = {}
+        self.received = 0
+        self.sent = 0
+
+    def __del__(self):
+        self.log.info('[ RANGE %d-%d ] %s received: %d sent: %d',
+                      self.a, self.b, self.addresses, self.received, self.sent)
+
+    def __str__(self):
+        txt = '\nRANGE_BEGIN {a} {b}\n'.format(a=self.a, b=self.b)
+        for addr in self.addresses:
+            txt += '        ADDRESS {0}\n'.format(addr)
+
+        for entry in self.stored:
+            txt += '\n'
+            txt += str(entry)
+        txt += 'RANGE_END\n\n'
+        return txt
+
+    def eligible(self, ident, address):
+        """ Return true if this range is eligible for fetching reply. """
+        if self.a <= ident <= self.b:
+            return (None is address
+                    or set() == self.addresses
+                    or address in self.addresses)
+        return False
+
+    def reply(self, query: dns.message.Message) -> Optional[DNSBlob]:
+        """Get answer for given query (adjusted if needed)."""
+        self.received += 1
+        for candidate in self.stored:
+            try:
+                candidate.match(query)
+                resp = candidate.reply(query)
+                # Probabilistic loss
+                if 'LOSS' in self.args:
+                    if random.random() < float(self.args['LOSS']):
+                        return DNSReplyServfail(query)
+                self.sent += 1
+                candidate.fired += 1
+                return resp
+            except ValueError:
+                pass
+        return DNSReplyServfail(query)
+
+
+class StepLogger(logging.LoggerAdapter):  # pylint: disable=too-few-public-methods
+    """
+    Prepent Step identification before each log message.
+    """
+    def process(self, msg, kwargs):
+        return '[STEP %s %s] %s' % (self.extra['id'], self.extra['type'], msg), kwargs
+
+
+class Step:
+    """
+    Step represents one scripted action in a given moment,
+    each step has an order identifier, type and optionally data entry.
+    """
+    require_data = ['QUERY', 'CHECK_ANSWER', 'REPLY']
+
+    def __init__(self, node):
+        """ Initialize single scenario step. """
+        self.node = node
+        self.id = int(node.value)
+        self.type = node["/type"].value
+        self.log = StepLogger(logging.getLogger('pydnstest.scenario.Step'),
+                              {'id': self.id, 'type': self.type})
+        try:
+            self.delay = int(node["/timestamp"].value)
+        except KeyError:
+            pass
+        self.data = [Entry(n) for n in node.match("/entry")]
+        self.queries = []
+        self.has_data = self.type in Step.require_data
+        self.answer = None
+        self.raw_answer = None
+        self.repeat_if_fail = 0
+        self.pause_if_fail = 0
+        self.next_if_fail = -1
+
+    def __str__(self):
+        txt = '\nSTEP {i} {t}'.format(i=self.id, t=self.type)
+        if self.repeat_if_fail:
+            txt += ' REPEAT {v}'.format(v=self.repeat_if_fail)
+        elif self.pause_if_fail:
+            txt += ' PAUSE {v}'.format(v=self.pause_if_fail)
+        elif self.next_if_fail != -1:
+            txt += ' NEXT {v}'.format(v=self.next_if_fail)
+        # if self.args:
+        #     txt += ' '
+        #     txt += ' '.join(self.args)
+        txt += '\n'
+
+        for data in self.data:
+            # from IPython.core.debugger import Tracer
+            # Tracer()()
+            txt += str(data)
+        return txt
+
+    def play(self, ctx):
+        """ Play one step from a scenario. """
+        if self.type == 'QUERY':
+            self.log.info('')
+            self.log.debug(self.data[0].message.to_text())
+            # Parse QUERY-specific parameters
+            choice, tcp, src_address = None, False, ctx.deckard_address
+            return self.__query(ctx, tcp=tcp, choice=choice, src_address=src_address)
+        elif self.type == 'CHECK_OUT_QUERY':  # ignore
+            self.log.info('')
+            return None
+        elif self.type == 'CHECK_ANSWER' or self.type == 'ANSWER':
+            self.log.info('')
+            return self.__check_answer(ctx)
+        elif self.type == 'TIME_PASSES ELAPSE':
+            self.log.info('')
+            return self.__time_passes()
+        elif self.type == 'REPLY' or self.type == 'MOCK':
+            self.log.info('')
+            return None
+        else:
+            raise NotImplementedError('step %03d type %s unsupported' % (self.id, self.type))
+
+    def __check_answer(self, ctx):
+        """ Compare answer from previously resolved query. """
+        if not self.data:
+            raise ValueError("response definition required")
+        expected = self.data[0]
+        if expected.raw_data is not None:
+            self.log.debug("raw answer: %s", ctx.last_raw_answer.to_text())
+            expected.cmp_raw(ctx.last_raw_answer)
+        else:
+            if ctx.last_answer is None:
+                raise ValueError("no answer from preceding query")
+            self.log.debug("answer: %s", ctx.last_answer.to_text())
+            expected.match(ctx.last_answer)
+
+    def __query(self, ctx, tcp=False, choice=None, src_address=None):
+        """
+        Send query and wait for an answer (if the query is not RAW).
+
+        The received answer is stored in self.answer and ctx.last_answer.
+        """
+        if not self.data:
+            raise ValueError("query definition required")
+        if self.data[0].raw_data is not None:
+            data_to_wire = self.data[0].raw_data
+        else:
+            # Don't use a message copy as the EDNS data portion is not copied.
+            data_to_wire = self.data[0].message.to_wire()
+        if choice is None or not choice:
+            choice = list(ctx.client.keys())[0]
+        if choice not in ctx.client:
+            raise ValueError('step %03d invalid QUERY target: %s' % (self.id, choice))
+
+        tstart = datetime.now()
+
+        # Send query and wait for answer
+        answer = None
+        sock = pydnstest.mock_client.setup_socket(ctx.client[choice][0],
+                                                  ctx.client[choice][1],
+                                                  tcp,
+                                                  src_address=src_address)
+        with sock:
+            pydnstest.mock_client.send_query(sock, data_to_wire)
+            if self.data[0].raw_data is None:
+                answer = pydnstest.mock_client.get_answer(sock)
+
+        # Track RTT
+        rtt = (datetime.now() - tstart).total_seconds() * 1000
+        global g_rtt, g_nqueries
+        g_nqueries += 1
+        g_rtt += rtt
+
+        # Remember last answer for checking later
+        self.raw_answer = answer
+        ctx.last_raw_answer = answer
+        if self.raw_answer is not None:
+            self.answer = dns.message.from_wire(self.raw_answer, one_rr_per_rrset=True)
+        else:
+            self.answer = None
+        ctx.last_answer = self.answer
+
+    def __time_passes(self):
+        """ Modify system time. """
+        file_old = os.environ["FAKETIME_TIMESTAMP_FILE"]
+        file_next = os.environ["FAKETIME_TIMESTAMP_FILE"] + ".next"
+        with open(file_old, 'r') as time_file:
+            line = time_file.readline().strip()
+        t = time.mktime(datetime.strptime(line, '@%Y-%m-%d %H:%M:%S').timetuple())
+        t += self.delay
+        with open(file_next, 'w') as time_file:
+            time_file.write(datetime.fromtimestamp(t).strftime('@%Y-%m-%d %H:%M:%S') + "\n")
+            time_file.flush()
+        os.replace(file_next, file_old)
+
+
+class Scenario:
+    log = logging.getLogger('pydnstest.scenatio.Scenario')
+
+    def __init__(self, node, filename, deckard_address=None):
+        """ Initialize scenario with description. """
+        self.node = node
+        self.info = node.value
+        self.file = filename
+        self.ranges = [Range(n) for n in node.match("/range")]
+        self.current_range = None
+        self.steps = [Step(n) for n in node.match("/step")]
+        self.current_step = None
+        self.client = {}
+        self.deckard_address = deckard_address
+
+    def __str__(self):
+        txt = 'SCENARIO_BEGIN'
+        if self.info:
+            txt += ' {0}'.format(self.info)
+        txt += '\n'
+        for range_ in self.ranges:
+            txt += str(range_)
+        for step in self.steps:
+            txt += str(step)
+        txt += "\nSCENARIO_END"
+        return txt
+
+    def reply(self, query: dns.message.Message, address=None) -> Optional[DNSBlob]:
+        """Generate answer packet for given query."""
+        current_step_id = self.current_step.id
+        # Unknown address, select any match
+        # TODO: workaround until the server supports stub zones
+        all_addresses = set()  # type: ignore
+        for rng in self.ranges:
+            all_addresses.update(rng.addresses)
+        if address not in all_addresses:
+            address = None
+        # Find current valid query response range
+        for rng in self.ranges:
+            if rng.eligible(current_step_id, address):
+                self.current_range = rng
+                return rng.reply(query)
+        # Find any prescripted one-shot replies
+        for step in self.steps:
+            if step.id < current_step_id or step.type != 'REPLY':
+                continue
+            try:
+                candidate = step.data[0]
+                candidate.match(query)
+                step.data.remove(candidate)
+                return candidate.reply(query)
+            except (IndexError, ValueError):
+                pass
+        return DNSReplyServfail(query)
+
+    def play(self, paddr):
+        """ Play given scenario. """
+        # Store test subject => address mapping
+        self.client = paddr
+
+        step = None
+        i = 0
+        while i < len(self.steps):
+            step = self.steps[i]
+            self.current_step = step
+            try:
+                step.play(self)
+            except ValueError as ex:
+                if step.repeat_if_fail > 0:
+                    self.log.info("[play] step %d: exception - '%s', retrying step %d (%d left)",
+                                  step.id, ex, step.next_if_fail, step.repeat_if_fail)
+                    step.repeat_if_fail -= 1
+                    if step.pause_if_fail > 0:
+                        time.sleep(step.pause_if_fail)
+                    if step.next_if_fail != -1:
+                        next_steps = [j for j in range(len(self.steps)) if self.steps[
+                            j].id == step.next_if_fail]
+                        if not next_steps:
+                            raise ValueError('step %d: wrong NEXT value "%d"' %
+                                             (step.id, step.next_if_fail)) from ex
+                        next_step = next_steps[0]
+                        if next_step < len(self.steps):
+                            i = next_step
+                        else:
+                            raise ValueError('step %d: Can''t branch to NEXT value "%d"' %
+                                             (step.id, step.next_if_fail)) from ex
+                    continue
+                ex_details = ex if self.log.isEnabledFor(logging.DEBUG) else None
+                raise ValueError('%s step %d %s' % (self.file, step.id, str(ex))) from ex_details
+            i += 1
+
+        for r in self.ranges:
+            for e in r.stored:
+                if e.mandatory and e.fired == 0:
+                    # TODO: cisla radku
+                    raise ValueError('Mandatory section at %s not fired' % e.mandatory.span)
+
+
+def get_next(file_in, skip_empty=True):
+    """ Return next token from the input stream. """
+    while True:
+        line = file_in.readline()
+        if not line:
+            return False
+        quoted, escaped = False, False
+        for i, char in enumerate(line):
+            if char == '\\':
+                escaped = not escaped
+            if not escaped and char == '"':
+                quoted = not quoted
+            if char == ';' and not quoted:
+                line = line[0:i]
+                break
+            if char != '\\':
+                escaped = False
+        tokens = ' '.join(line.strip().split()).split()
+        if not tokens:
+            if skip_empty:
+                continue
+            return '', []
+        op = tokens.pop(0)
+        return op, tokens
+
+
+def parse_config(scn_cfg, qmin, installdir):  # FIXME: pylint: disable=too-many-statements
+    """
+    Transform scene config (key, value) pairs into dict filled with defaults.
+    Returns tuple:
+      context dict: {Jinja2 variable: value}
+      trust anchor dict: {domain: [TA lines for particular domain]}
+    """
+    # defaults
+    do_not_query_localhost = True
+    harden_glue = True
+    sockfamily = 0  # auto-select value for socket.getaddrinfo
+    trust_anchor_list = []
+    trust_anchor_files = {}
+    negative_ta_list = []
+    stub_addr = None
+    stub_name = "k.root-servers.net"
+    override_timestamp = None
+    forward_addr = None
+    do_ip6 = True
+    do_ip4 = True
+    features = {}
+    feature_list_delimiter = ';'
+    feature_pair_delimiter = '='
+
+    for k, v in scn_cfg:
+        # Enable selectively for some tests
+        if k == 'do-not-query-localhost':
+            do_not_query_localhost = str2bool(v)
+        elif k == 'domain-insecure':
+            negative_ta_list.append(v)
+        elif k == 'harden-glue':
+            harden_glue = str2bool(v)
+        elif k == 'query-minimization':
+            qmin = str2bool(v)
+        elif k == 'trust-anchor':
+            trust_anchor = v.strip('"\'')
+            trust_anchor_list.append(trust_anchor)
+            domain = dns.name.from_text(trust_anchor.split()[0]).canonicalize()
+            if domain not in trust_anchor_files:
+                trust_anchor_files[domain] = []
+            trust_anchor_files[domain].append(trust_anchor)
+        elif k == 'val-override-timestamp':
+            override_timestamp_str = v.strip('"\'')
+            override_timestamp = int(override_timestamp_str)
+        elif k == 'val-override-date':
+            override_date_str = v.strip('"\'')
+            ovr_yr = override_date_str[0:4]
+            ovr_mnt = override_date_str[4:6]
+            ovr_day = override_date_str[6:8]
+            ovr_hr = override_date_str[8:10]
+            ovr_min = override_date_str[10:12]
+            ovr_sec = override_date_str[12:]
+            override_date_str_arg = '{0} {1} {2} {3} {4} {5}'.format(
+                ovr_yr, ovr_mnt, ovr_day, ovr_hr, ovr_min, ovr_sec)
+            override_date = time.strptime(override_date_str_arg, "%Y %m %d %H %M %S")
+            override_timestamp = calendar.timegm(override_date)
+        elif k == 'stub-addr':
+            stub_addr = v.strip('"\'')
+        elif k == 'stub-name':
+            stub_name = v
+        elif k == 'features':
+            feature_list = v.split(feature_list_delimiter)
+            try:
+                for f_item in feature_list:
+                    if f_item.find(feature_pair_delimiter) != -1:
+                        f_key, f_value = [x.strip()
+                                          for x
+                                          in f_item.split(feature_pair_delimiter, 1)]
+                    else:
+                        f_key = f_item.strip()
+                        f_value = ""
+                    features[f_key] = f_value
+            except KeyError as ex:
+                raise KeyError("can't parse features (%s) in config section (%s)"
+                               % (v, str(ex))) from ex
+        elif k == 'feature-list':
+            try:
+                f_key, f_value = [x.strip() for x in v.split(feature_pair_delimiter, 1)]
+                if f_key not in features:
+                    features[f_key] = []
+                f_value = f_value.replace("{{INSTALL_DIR}}", installdir)
+                features[f_key].append(f_value)
+            except KeyError as ex:
+                raise KeyError("can't parse feature-list (%s) in config section (%s)"
+                               % (v, str(ex))) from ex
+        elif k == 'force-ipv6' and v.upper() == 'TRUE':
+            sockfamily = socket.AF_INET6
+        elif k == 'forward-addr':  # currently forwards everything
+            forward_addr = v.strip('"\'')
+        elif k == 'do-ip4':
+            do_ip4 = str2bool(v)
+        elif k == 'do-ip6':
+            do_ip6 = str2bool(v)
+        else:
+            raise NotImplementedError('unsupported CONFIG key "%s"' % k)
+
+    ctx = {
+        "DO_NOT_QUERY_LOCALHOST": str(do_not_query_localhost).lower(),
+        "NEGATIVE_TRUST_ANCHORS": negative_ta_list,
+        "FEATURES": features,
+        "HARDEN_GLUE": str(harden_glue).lower(),
+        "INSTALL_DIR": installdir,
+        "QMIN": str(qmin).lower(),
+        "TRUST_ANCHORS": trust_anchor_list,
+        "TRUST_ANCHOR_FILES": trust_anchor_files,
+        "FORWARD_ADDR": forward_addr,
+        "DO_IP6": str(do_ip6).lower(),
+        "DO_IP4": str(do_ip4).lower(),
+    }
+    if stub_addr:
+        ctx['ROOT_ADDR'] = stub_addr
+        ctx['ROOT_NAME'] = stub_name
+        # determine and verify socket family for specified root address
+        gai = socket.getaddrinfo(stub_addr, 53, sockfamily, 0,
+                                 socket.IPPROTO_UDP, socket.AI_NUMERICHOST)
+        assert len(gai) == 1
+        sockfamily = gai[0][0]
+    if not sockfamily:
+        sockfamily = socket.AF_INET  # default to IPv4
+    ctx['_SOCKET_FAMILY'] = sockfamily
+    if override_timestamp:
+        ctx['_OVERRIDE_TIMESTAMP'] = override_timestamp
+    return ctx
+
+
+def parse_file(path, deckard_address=None):
+    """ Parse scenario from a file. """
+
+    aug = pydnstest.augwrap.AugeasWrapper(
+        confpath=path, lens='Deckard', loadpath=os.path.dirname(__file__))
+    node = aug.tree
+    config = []
+    for line in [c.value for c in node.match("/config/*")]:
+        if line:
+            if not line.startswith(';'):
+                if '#' in line:
+                    line = line[0:line.index('#')]
+                # Break to key-value pairs
+                # e.g.: ['minimization', 'on']
+                kv = [x.strip() for x in line.split(':', 1)]
+                if len(kv) >= 2:
+                    config.append(kv)
+    scenario = Scenario(node["/scenario"], os.path.basename(node.path), deckard_address)
+    return scenario, config