"""matchpart is used to compare two DNS messages using a single criterion"""
from typing import ( # noqa
Any, Hashable, Sequence, Tuple, Union)
import dns.edns
import dns.rcode
import dns.set
MismatchValue = Union[str, Sequence[Any]]
class DataMismatch(Exception):
def __init__(self, exp_val, got_val):
super().__init__()
self.exp_val = exp_val
self.got_val = got_val
@staticmethod
def format_value(value: MismatchValue) -> str:
if isinstance(value, list):
return ' '.join([str(val) for val in value])
else:
return str(value)
def __str__(self) -> str:
return 'expected "{}" got "{}"'.format(
self.format_value(self.exp_val),
self.format_value(self.got_val))
def __eq__(self, other):
return (isinstance(other, DataMismatch)
and self.exp_val == other.exp_val
and self.got_val == other.got_val)
def __ne__(self, other):
return not self.__eq__(other)
@property
def key(self) -> Tuple[Hashable, Hashable]:
def make_hashable(value):
if isinstance(value, (list, dns.set.Set)):
value = (make_hashable(item) for item in value)
value = tuple(value)
return value
return (make_hashable(self.exp_val), make_hashable(self.got_val))
def __hash__(self) -> int:
return hash(self.key)
def compare_val(exp, got):
"""Compare arbitraty objects, throw exception if different. """
if exp != got:
raise DataMismatch(exp, got)
return True
def compare_rrs(expected, got):
""" Compare lists of RR sets, throw exception if different. """
for rr in expected:
if rr not in got:
raise DataMismatch(expected, got)
for rr in got:
if rr not in expected:
raise DataMismatch(expected, got)
if len(expected) != len(got):
raise DataMismatch(expected, got)
return True
def compare_rrs_types(exp_val, got_val, skip_rrsigs):
"""sets of RR types in both sections must match"""
def rr_ordering_key(rrset):
if rrset.covers:
return rrset.covers, 1 # RRSIGs go to the end of RRtype list
else:
return rrset.rdtype, 0
def key_to_text(rrtype, rrsig):
if not rrsig:
return dns.rdatatype.to_text(rrtype)
else:
return 'RRSIG(%s)' % dns.rdatatype.to_text(rrtype)
if skip_rrsigs:
exp_val = (rrset for rrset in exp_val
if rrset.rdtype != dns.rdatatype.RRSIG)
got_val = (rrset for rrset in got_val
if rrset.rdtype != dns.rdatatype.RRSIG)
exp_types = frozenset(rr_ordering_key(rrset) for rrset in exp_val)
got_types = frozenset(rr_ordering_key(rrset) for rrset in got_val)
if exp_types != got_types:
exp_types = tuple(key_to_text(*i) for i in sorted(exp_types))
got_types = tuple(key_to_text(*i) for i in sorted(got_types))
raise DataMismatch(exp_types, got_types)
def check_question(question):
if len(question) > 2:
raise NotImplementedError("More than one record in QUESTION SECTION.")
def match_opcode(exp, got):
return compare_val(exp.opcode(),
got.opcode())
def match_qtype(exp, got):
check_question(exp.question)
check_question(got.question)
if not exp.question and not got.question:
return True
if not exp.question:
raise DataMismatch("<empty question>", got.question[0].rdtype)
if not got.question:
raise DataMismatch(exp.question[0].rdtype, "<empty question>")
return compare_val(exp.question[0].rdtype,
got.question[0].rdtype)
def match_qname(exp, got):
check_question(exp.question)
check_question(got.question)
if not exp.question and not got.question:
return True
if not exp.question:
raise DataMismatch("<empty question>", got.question[0].name)
if not got.question:
raise DataMismatch(exp.question[0].name, "<empty question>")
return compare_val(exp.question[0].name,
got.question[0].name)
def match_qcase(exp, got):
check_question(exp.question)
check_question(got.question)
if not exp.question and not got.question:
return True
if not exp.question:
raise DataMismatch("<empty question>", got.question[0].name.labels)
if not got.question:
raise DataMismatch(exp.question[0].name.labels, "<empty question>")
return compare_val(exp.question[0].name.labels,
got.question[0].name.labels)
def match_subdomain(exp, got):
if not exp.question:
return True
if got.question:
qname = got.question[0].name
else:
qname = dns.name.root
if exp.question[0].name.is_superdomain(qname):
return True
raise DataMismatch(exp, got)
def match_flags(exp, got):
return compare_val(dns.flags.to_text(exp.flags),
dns.flags.to_text(got.flags))
def match_rcode(exp, got):
return compare_val(dns.rcode.to_text(exp.rcode()),
dns.rcode.to_text(got.rcode()))
def match_answer(exp, got):
return compare_rrs(exp.answer,
got.answer)
def match_answertypes(exp, got):
return compare_rrs_types(exp.answer,
got.answer, skip_rrsigs=True)
def match_answerrrsigs(exp, got):
return compare_rrs_types(exp.answer,
got.answer, skip_rrsigs=False)
def match_authority(exp, got):
return compare_rrs(exp.authority,
got.authority)
def match_additional(exp, got):
return compare_rrs(exp.additional,
got.additional)
def match_edns(exp, got):
if got.edns != exp.edns:
raise DataMismatch(exp.edns,
got.edns)
if got.payload != exp.payload:
raise DataMismatch(exp.payload,
got.payload)
def match_nsid(exp, got):
nsid_opt = None
for opt in exp.options:
if opt.otype == dns.edns.NSID:
nsid_opt = opt
break
# Find matching NSID
for opt in got.options:
if opt.otype == dns.edns.NSID:
if not nsid_opt:
raise DataMismatch(None, opt.data)
if opt == nsid_opt:
return True
else:
raise DataMismatch(nsid_opt.data, opt.data)
if nsid_opt:
raise DataMismatch(nsid_opt.data, None)
return True
MATCH = {"opcode": match_opcode, "qtype": match_qtype, "qname": match_qname, "qcase": match_qcase,
"subdomain": match_subdomain, "flags": match_flags, "rcode": match_rcode,
"answer": match_answer, "answertypes": match_answertypes,
"answerrrsigs": match_answerrrsigs, "authority": match_authority,
"additional": match_additional, "edns": match_edns,
"nsid": match_nsid}
def match_part(exp, got, code):
try:
return MATCH[code](exp, got)
except KeyError:
raise NotImplementedError('unknown match request "%s"' % code)
