def test_authority_domain(self):
question = Question(Name("server1.gumpe"), Type.A, Class.IN)
header = Header(1337, 0, 1, 0, 0, 0)
query = Message(header, questions=[question])
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.sendto(query.to_bytes(), (SERVER, PORT))
data = s.recv(512)
s.close()
message = Message.from_bytes(data)
self.assertCountEqual(message.answers, [
ResourceRecord(
name=Name("server1.gumpe."),
type_=Type.A,
class_=Class.IN,
ttl=0,
rdata=ARecordData("10.0.1.5"),
),
ResourceRecord(
name=Name("server1.gumpe."),
type_=Type.A,
class_=Class.IN,
ttl=0,
rdata=ARecordData("10.0.1.4"),
),
])
def from_bytes(cls, packet):
"""Create Message from bytes.
Args:
packet (bytes): byte representation of the message.
"""
header, offset = Header.from_bytes(packet), 12
questions = []
for _ in range(header.qd_count):
question, offset = Question.from_bytes(packet, offset)
questions.append(question)
answers = []
for _ in range(header.an_count):
answer, offset = ResourceRecord.from_bytes(packet, offset)
answers.append(answer)
authorities = []
for _ in range(header.ns_count):
authority, offset = ResourceRecord.from_bytes(packet, offset)
authorities.append(authority)
additionals = []
for _ in range(header.ar_count):
additional, offset = ResourceRecord.from_bytes(packet, offset)
additionals.append(additional)
return cls(header, questions, answers, authorities, additionals)
def consult_cache(self, questions):
answers = []
for q in questions:
res, iplist, namelist = self.check_cache(q.qname)
if res:
for ip in iplist:
answers.append(ResourceRecord(q.qname, Type.A, Class.IN, self.ttl, ARecordData(ip)))
for n in namelist:
answers.append(ResourceRecord(q.qname, Type.CNAME, Class.IN, self.ttl, CNAMERecordData(n)))
return answers
def test_resource_to_bytes(self):
name = MagicMock()
name.to_bytes.return_value = b"\x07example\x03com\x00"
rdata = MagicMock()
rdata.to_bytes.return_value = b"\x04\x05\x06\x07"
record = ResourceRecord(name, Type.A, Class.CS, 3, rdata)
compress = {}
self.assertEqual(
record.to_bytes(0, compress),
(b"\x07example\x03com\x00\x00\x01\x00\x02\x00\x00\x00\x03\x00"
b"\x04\x04\x05\x06\x07"))
def test_resource_from_bytes(self, MockName, MockRData):
MockName.from_bytes.return_value = (Name("example.com"), 13)
MockRData.create_from_bytes.return_value = ARecordData("1.1.1.1")
packet = (b"\x07example\x03com\x00\x00\x01\x00\x02\x00\x00\x00\x03\x00"
b"\x04\x01\x01\x01\x01")
record1, offset = ResourceRecord.from_bytes(packet, 0)
record2 = ResourceRecord(Name("example.com"), Type.A, Class.CS, 3,
ARecordData("1.1.1.1"))
self.assertEqual(record1, record2)
MockName.from_bytes.assert_called_with(packet, 0)
MockRData.create_from_bytes.assert_called_with(Type.A, packet, 23, 4)
def test_concurrent_requests(self):
queries = []
answers = []
question = Question(Name("gaia.cs.umass.edu"), Type.A, Class.IN)
header = Header(1337, 0, 1, 0, 0, 0)
header.rd = 1
queries.append(Message(header, questions=[question]))
answers.append([
ResourceRecord(name=Name("gaia.cs.umass.edu"),
type_=Type.A,
class_=Class.IN,
ttl=0,
rdata=ARecordData("128.119.245.12")),
])
question = Question(Name("server2.gumpe"), Type.A, Class.IN)
header = Header(420, 0, 1, 0, 0, 0)
queries.append(Message(header, questions=[question]))
answers.append([
ResourceRecord(name=Name("server2.gumpe"),
type_=Type.A,
class_=Class.IN,
ttl=0,
rdata=ARecordData("10.0.1.7")),
])
header = Header(69, 0, 1, 0, 0, 0)
question = Question(Name("www.gumpe"), Type.A, Class.IN)
queries.append(Message(header, questions=[question]))
answers.append([
ResourceRecord(name=Name("www.gumpe"),
type_=Type.A,
class_=Class.IN,
ttl=0,
rdata=ARecordData("10.0.1.7")),
ResourceRecord(name=Name("www.gumpe"),
type_=Type.CNAME,
class_=Class.IN,
ttl=0,
rdata=CNAMERecordData(Name("server2.gumpe"))),
])
sockets = [
socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
for _ in range(len(queries))
]
for i in range(len(sockets)):
sockets[i].sendto(queries[i].to_bytes(), (SERVER, PORT))
responses = []
for i in range(len(sockets)):
responses.append(Message.from_bytes(sockets[i].recv(1024)))
for i in range(len(sockets)):
sockets[i].close()
for i in range(len(queries)):
self.assertCountEqual(responses[i].answers, answers[i])
def testCache(self):
cac = RecordCache(0)
self.assertEqual(cac.lookup("abcdefghqqqq.com", Type.A, Class.IN), [])
test = ResourceRecord("blabla.com", Type.A, Class.IN, 0,
ARecordData("111.111.111.111"))
cac.add_record(test)
self.assertEqual(cac.lookup("blabla.com", Type.A, Class.IN), test)
def read_master_file(self, filename):
"""Read the zone from a master file
See section 5 of RFC 1035.
Args:
filename (str): the filename of the master file
"""
temp = []
"""Read the cache file from disk"""
with open("roothints.md") as file_:
lines = file_.readlines()
for l in lines:
#remove comments
b = re.sub(r';[^\n]*', "", l)
te = l.split()
if (te[0] != ';'):
temp.append(te)
if ("." in te[0]):
type_ = self.getType(te[2])
if (type_ == Type.A):
rdata = ARecordData(te[3])
elif (type_ == Type.NS):
rdata = NSRecordData(te[3])
elif (type_ == Type.CNAME):
rdata = CNAMERecordData(te[3])
rr = ResourceRecord(te[0], type_, Class.IN, te[1], rdata)
self.records.update({te[0]: rr})
def read_cache_file(self, cache_file=Consts.CACHE_FILE):
""" Read the cache file from disk """
#Empty current cache
self.records = []
#Load from file
try:
with open(cache_file + ".timestamp") as infile:
self.lastCleanup = int(infile.readline())
with open(cache_file, "r") as infile:
curTime = int(time.time())
dcts = json.load(infile)
self.records = [ResourceRecord.from_dict(dct) for dct in dcts]
#Don't add the entries whose TTL is expired and update the ttls
self.cleanup()
except (ValueError, IOError, FileNotFoundError) as e:
print("An error has occured while loading cache from disk: " +
str(e))
with open(cache_file, 'w') as outfile:
json.dump([], outfile, indent=2)
with open(cache_file + ".timestamp", 'w') as outfile:
outfile.write(str(self.lastCleanup))
if isinstance(e, FileNotFoundError):
print("Missing files were created")
self.records = []
def read_master_file(self, filename):
"""Read the zone from a master file
See section 5 of RFC 1035.
Args:
filename (str): the filename of the master file
"""
records = re.finditer(
Zone.record_re, open(filename, "r").read(), flags=re.MULTILINE
)
for r in records:
domain, ttl, class_, type_, rdata = r.groups()
domain = domain or self.last_domain
self.last_domain = domain
record = ResourceRecord(
name=Name(domain),
type_=Type[type_],
class_=Class[class_],
ttl=int(ttl) if ttl is not None else Zone.default_ttl,
rdata=RecordData.create_from_str(Type[type_], rdata)
)
if domain in self.records:
self.records[domain].append(record)
else:
self.records[domain] = [record]
def serve(self):
"""Start serving requests"""
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.bind(("", self.port))
while not self.done:
data, address = sock.recvfrom(65565)
message = Message.from_bytes(data)
rd = message.header.rd
rcode = 0
aa = 1
self.log("REQUEST RECIEVED:", address)
answers, authorities, additionals = self.zone_resolution(message.questions)
if answers == []:
if authorities == [] and additionals == []:
self.log("\tZONE RESOLUTION FAILED")
answers = self.consult_cache(message.questions)
if answers == []:
self.log("\tCACHE LOOKUP FAILED")
rcode = 3
else:
aa = 0
if rcode == 3 and rd == 1:
rcode = 0
self.log("\tCALLING RESOLVER")
resolver = Resolver(5, True, 0)
resolver.rd = 0
resolver.rootip = "198.41.0.4"
for q in message.questions:
self.log("\t\tRESOLVING:", q.qname)
hostname, namelist, iplist = resolver.gethostbyname(str(q.qname))
if hostname == str(q.qname):
for ip in iplist:
answers.append(ResourceRecord(q.qname, Type.A, Class.IN, self.ttl, ARecordData(ip)))
for n in namelist:
answers.append(ResourceRecord(q.qname, Type.CNAME, Class.IN, self.ttl, CNAMERecordData(n)))
self.log("SENDING RESPONSE:", rcode, "\n")
mess = self.build_message(message.header.ident, rd, aa, rcode, message.questions, answers, authorities, additionals)
sock.sendto(mess.to_bytes(), address)
def setUp(self):
# put invalid record in cache file
record_data = RecordData.create(Type.A, "192.168.123.456")
self.rr = ResourceRecord("invalid.invalid", Type.A, Class.IN, 3,
record_data)
cache = RecordCache()
cache.add_record(self.rr)
cache.write_cache_file()
def read_cache_file(self):
"""Read the cache file from disk"""
dcts = []
try:
with open("cache", "r") as file_:
dcts = json.load(file_)
except:
print("could not read cache")
self.records = [ResourceRecord.from_dict(dct) for dct in dcts]
def test_cache_lookup(self):
"""
Add a record to the cache and look it up
"""
rr = ResourceRecord("wiki.nl", Type.A, Class.IN, self.ttl,
RecordData.create(Type.A, "192.168.123.456"))
cache = RecordCache()
cache.add_record(rr)
lookup_vals = cache.lookup("wiki.nl", Type.A, Class.IN)
self.assertEqual([rr], lookup_vals)
def analyze_response(self, response):
additionals = list(
) # this list makes sure no cache lookups for additional information are necessary.
for additional_rr in response.additionals:
try:
self.CACHE.add_record(additional_rr)
additionals.append(additional_rr)
except CacheException:
pass
for answer_rr in response.answers:
if answer_rr.type_ == Type.A:
self.CACHE.add_record(answer_rr)
self.addresses.append(answer_rr.rdata.data)
elif answer_rr.type_ == Type.CNAME:
self.CACHE.add_record(answer_rr)
new_sname = answer_rr.rdata.data
try:
cname_resolver = Resolver(self.caching, self.CACHE)
self.SNAME, self.addresses, self.aliases = cname_resolver.gethostbyname(
new_sname)
except ResolverException:
pass
return
else:
raise ResolverException(RCode.FormErr)
if response.answers:
for additional in additionals:
self.aliases.append(additional.rdata.data)
return
new_slist = list()
for authority in response.authorities:
rr = ResourceRecord(authority.name, authority.type_,
authority.class_, authority.ttl,
authority.rdata)
if rr.type_ == Type.NS:
self.CACHE.add_record(rr)
ip = None
for additional in additionals:
if additional.name == rr.rdata.data and additional.type_ == Type.A:
ip = additional.rdata.data
new_slist.append((rr.rdata.data, ip))
elif rr.type_ == Type.SOA:
pass
else:
raise ResolverException(RCode.FormErr)
if new_slist:
try:
next_resolver = Resolver(self.caching, self.CACHE)
self.SNAME, self.addresses, self.aliases = next_resolver.gethostbyname(
self.SNAME, new_slist)
except ResolverException:
pass
def test_expired_cache_entry(self):
cache = RecordCache(0)
record = ResourceRecord(
name=Name("bonobo.putin"),
type_=Type.A,
class_=Class.IN,
ttl=0,
rdata=ARecordData("1.0.0.1"),
)
cache.add_record(record)
self.assertEqual(cache.lookup(Name("bonobo.putin"), Type.A, Class.IN),
None)
def test_invalid_domain_from_cache(self):
cache = RecordCache(0)
record = ResourceRecord(
name=Name("bonobo.putin"),
type_=Type.A,
class_=Class.IN,
ttl=60,
rdata=ARecordData("1.0.0.1"),
)
cache.add_record(record)
self.assertEqual(cache.lookup(Name("bonobo.putin"), Type.A, Class.IN),
record)
def test_expired_cache_entry(self):
cache = RecordCache(0)
resolver = Resolver(5, cache)
cache.add_record(
ResourceRecord(
name=Name("hw.gumpe"),
type_=Type.A,
class_=Class.IN,
ttl=0,
rdata=ARecordData("1.0.0.2"),
))
cache.add_record(
ResourceRecord(
name=Name("hw.gumpe"),
type_=Type.CNAME,
class_=Class.IN,
ttl=0,
rdata=CNAMERecordData(Name("gumpe.hw")),
))
self.assertEqual(resolver.gethostbyname("hw.gumpe"),
("hw.gumpe", [], []))
def test_invalid_domain_from_cache(self):
cache = RecordCache(0)
resolver = Resolver(5, cache)
cache.add_record(
ResourceRecord(
name=Name("bonobo.putin"),
type_=Type.A,
class_=Class.IN,
ttl=60,
rdata=ARecordData("1.0.0.1"),
))
cache.add_record(
ResourceRecord(
name=Name("bonobo.putin"),
type_=Type.CNAME,
class_=Class.IN,
ttl=60,
rdata=CNAMERecordData(Name("putin.bonobo")),
))
self.assertEqual(resolver.gethostbyname("bonobo.putin"),
("bonobo.putin", ["putin.bonobo."], ["1.0.0.1"]))
def read_master_file(self, filename):
"""Read the zone from a master file
See section 5 of RFC 1035.
Args:
filename (str): the filename of the master file
"""
typeData = {"NS": "nsdname", "A": "address", "CNAME": "cname"}
try:
with open(filename, "r") as file_:
for l in file_:
rr = l.split(";")[0]
if not rr:
continue
entries = re.split("[\\n]?[\ +]*[\\t+]*", rr)[:-1]
name = entries[0]
ttl = int(entries[1])
type_ = entries[2]
address = entries[3]
if type_ not in typeData:
continue
rr = {
"type": type_,
"name": name,
"class": "IN",
"ttl": ttl,
"rdata": {
typeData[type_]: address
}
}
if name not in self.records:
self.records[name] = [ResourceRecord.from_dict(rr)]
else:
self.records[name].append(ResourceRecord.from_dict(rr))
except:
print("could not read zone file")
return self
def test_TTL_expiration(self):
"""
cache a record, wait till ttl expires, see if record is removed from cache
"""
rr = ResourceRecord("wiki.nl", Type.A, Class.IN, self.ttl,
RecordData.create(Type.A, "192.168.123.456"))
cache = RecordCache()
cache.add_record(rr)
time.sleep(rr.ttl)
lookup_vals = cache.lookup("wiki.nl", Type.A, Class.IN)
self.assertFalse(lookup_vals)
def resource_from_json(dct):
""" Convert JSON object to ResourceRecord
Usage:
records = json.loads(string, object_hook=resource_from_json)
"""
name = dct["name"]
type_ = Type.from_string(dct["type"])
class_ = Class.from_string(dct["class"])
ttl = dct["ttl"]
rdata = RecordData.create(type_, dct["rdata"])
t = dct["time"]
return ResourceRecord(name, type_, class_, ttl, rdata, t)
def test_ttl_overwrite(self):
cache = RecordCache(60)
record = ResourceRecord(
name=Name("bonobo.putin"),
type_=Type.A,
class_=Class.IN,
ttl=0,
rdata=ARecordData("1.0.0.1"),
)
cache.add_record(record)
cache_entry = cache.lookup(Name("bonobo.putin"), Type.A, Class.IN)
self.assertEqual(cache_entry, record)
self.assertEqual(cache_entry.ttl, 60)
def from_bytes(cls, packet):
""" Create Message from bytes
Args:
packet (bytes): byte representation of the message
"""
parser = Parser()
# Parse header
header, offset = Header.from_bytes(packet), 12
# Parse questions
questions = []
for _ in range(header.qd_count):
question, offset = Question.from_bytes(packet, offset, parser)
questions.append(question)
# Parse answers
answers = []
for _ in range(header.an_count):
answer, offset = ResourceRecord.from_bytes(packet, offset, parser)
answers.append(answer)
# Parse authorities
authorities = []
for _ in range(header.ns_count):
authority, offset = ResourceRecord.from_bytes(packet, offset, parser)
authorities.append(authority)
# Parse additionals
additionals = []
for _ in range(header.ar_count):
additional, offset = ResourceRecord.from_bytes(packet, offset, parser)
additionals.append(additional)
return cls(header, questions, answers, authorities, additionals)
def load_and_parse(self, content):
content = re.sub(re.compile(";.*?\n"), "\n", content) #Remove comments
content = re.sub(re.compile("\n\n*\n"), "\n",
content) #Remove whitespaces
content = re.sub(re.compile(" * "), " ",
content) #Remove multiple spaces between words
content = re.sub(re.compile("\t\t*\t"), " ",
content) #Remove tabs between words
content = re.sub(re.compile("\n *"), "\n",
content) #Remove spaces at start of line
content = re.sub(re.compile("\n\t*"), "\n",
content) #Remove tabs at start of line
content = re.compile(r'\(.*?\)', re.DOTALL)\
.sub(lambda x: x.group().replace('\n', ''), content) #Remove newlines between ()
content = re.sub(re.compile("\t+"), " ",
content) #Remove tabs between words
default_ttl = None
origin = None
recordSet = []
for line in content.split('\n'):
if line[:4] == "$TTL":
prev_ttl = self.time_to_seconds(line[4:].strip())
elif line[:7] == "$ORIGIN":
origin = line[7:].strip()
elif "SOA" not in line:
parts = line.split(' ')
rr_name = parts[0]
rr_ttl = self.time_to_seconds(parts[1])
offset = int(rr_ttl == 0)
if offset:
rr_ttl = prev_ttl
rr_class = Class[parts[1 + offset]]
rr_type = parts[2 + offset]
if Type[rr_type] == Type.CNAME or Type[rr_type] == Type.NS:
rr_data = RecordData.create(
Type[rr_type], Name(parts[3 + offset].rstrip('.')))
else:
rr_data = RecordData.create(Type[rr_type],
parts[3 + offset].rstrip('.'))
self.add_node(
rr_name,
ResourceRecord(Name(rr_name), Type[rr_type], rr_class,
rr_ttl, rr_data))
def test_outside_zone(self):
question = Question(Name("gaia.cs.umass.edu"), Type.A, Class.IN)
header = Header(1337, 0, 1, 0, 0, 0)
header.rd = 1
query = Message(header, questions=[question])
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.sendto(query.to_bytes(), (SERVER, PORT))
data = s.recv(512)
s.close()
message = Message.from_bytes(data)
self.assertEqual(message.answers, [
ResourceRecord(name=Name("gaia.cs.umass.edu"),
type_=Type.A,
class_=Class.IN,
ttl=0,
rdata=ARecordData("128.119.245.12")),
])
def test_cache_disk_io(self):
"""
Add a record to the cache, write to disk, read from disk, do a lookup
"""
rr = ResourceRecord("wiki.nl", Type.A, Class.IN, self.ttl,
RecordData.create(Type.A, "192.168.123.456"))
cache = RecordCache()
cache.write_cache_file() # overwrite the current cache file
# add rr to cache and write to disk
cache.add_record(rr)
cache.write_cache_file()
# read from disk again
new_cache = RecordCache()
new_cache.read_cache_file()
lookup_vals = new_cache.lookup("wiki.nl", Type.A, Class.IN)
self.assertEqual([rr], lookup_vals)
def lookup(self, dname, type_, class_):
"""Lookup resource records in cache
Lookup for the resource records for a domain name with a specific type
and class.
Args:
dname (str): domain name
type_ (Type): type
class_ (Class): class
"""
dname = Name(dname)
rrs = [
ResourceRecord.from_dict(r) for r in self.records
if (time.time() - r["timestamp"]) < r["ttl"]
]
rs = [
r for r in rrs
if r.name == dname and r.class_ == class_ and r.type_ == type_
]
return rs
def setUpClass(cls):
cls.ttl = 3
rr = ResourceRecord("wiki.nl", Type.A, Class.IN, cls.ttl,
RecordData.create(Type.A, "192.168.123.456"))
def getType(t):
if(t == 'A'):
return Type.A
if(t == 'NS'):
return Type.NS
if(t == 'CNAME'):
return Type.CNAME
temp = []
"""Read the cache file from disk"""
with open("roothints.md") as file_:
lines = file_.readlines()
for l in lines:
#remove comments
b = re.sub(r';[^\n]*', "", l)
te = l.split()
if(te[0] != ';'):
temp.append(te)
if("." in te[0]):
type_ = getType(te[2])
if(type_ == Type.A):
rdata = ARecordData(te[3])
elif(type_ == Type.NS):
rdata = NSRecordData(te[3])
elif(type_ == Type.CNAME):
rdata = CNAMERecordData(te[3])
rr = ResourceRecord(te[0], type_, Class.IN, te[1], rdata)
print(rr.to_dict())
def handle_request(self):
""" Attempts to answer the received query """
#Check this next to the given algorithm
#print("Catalog:",self.catalog.zones)
#for zone in self.catalog.zones:
# print("Records:",self.catalog.zones[zone].records)
if self.message.header.opcode != 0: #Send a not implemented error, we don't need to support those kinds of queries
print("[-] - Received a nonstandard query. This is unsupported.")
header = Header(ident, 0, 1, 0, 0, 0)
header.qr = 1
header.rd = self.message.header.rd
header.ra = 1
header.rcode = 4
self.sendResponse(Message(header, self.message.questions, []))
return
#print("[*] - Handling request.")
if len(self.message.questions) != 1: #Send a format error response
print("[-] - Invalid request.")
header = Header(ident, 0, 1, 0, 0, 0)
header.qr = 1
header.rd = self.message.header.rd
header.ra = 1
header.rcode = 1
self.sendResponse(Message(header, self.message.questions, []))
return
#print("MSG:",self.message)
#print("RECEIVED QUESTION",self.message.questions[0])
hname = str(self.message.questions[0].qname)
#print("Solving",hname,type(hname))
ident = self.message.header.ident
#print("Checking zone")
answer, authority, found = self.check_zone(hname)
#print("Wat we in de zone hebben gevonden")
#print("ANS:",answer,"AUTH:",authority,"FOUND:",found)
#found = False
if found:
print("Found in zone")
header = Header(ident, 0, 1, len(answer), len(authority), 0)
header.qr = 1
header.aa = 1
header.rd = self.message.header.rd
header.ra = 1
self.sendResponse(
Message(header, self.message.questions, answer, authority))
elif self.message.header.rd == 1:
h, al, ad = self.resolver.gethostbyname(hname)
#Make and send th appropriate response
header = Header(ident, 0, 1, len(al) + len(ad), 0, 0)
header.qr = 1
header.rd = self.message.header.rd
header.ra = 1
aliases = [
ResourceRecord(Name(h), Type.CNAME, Class.IN, self.ttl,
RecordData.create(Type.CNAME, Name(alias)))
for alias in al
]
addresses = [
ResourceRecord(Name(h), Type.A, Class.IN, self.ttl,
RecordData.create(Type.A, address))
for address in ad
]
self.sendResponse(
Message(header, self.message.questions, aliases + addresses))
else: #Send an empty response
header = Header(ident, 0, 1, 0, 0, 0)
header.qr = 1
header.rd = self.message.header.rd
header.ra = 1
header.rcode = 0
self.sendResponse(Message(header, self.message.questions, []))
