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 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 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 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 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 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 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"])
return ResourceRecord(name, type_, class_, ttl, rdata)
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_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 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 setUpClass(cls):
cls.ttl = 3
rr = ResourceRecord("wiki.nl", Type.A, Class.IN, cls.ttl, RecordData.create(Type.A, "192.168.123.456"))
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 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, []))