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"""Libknot probe interface wrapper."""
import ctypes
import datetime
import enum
import socket
import libknot
class KnotProbeDataProto(enum.IntEnum):
"""Libknot probe transport protocol types."""
UDP = 0
TCP = 1
QUIC = 3
TLS = 4
HTTPS = 5
class KnotProbeDataDNSHdr(ctypes.BigEndianStructure):
"""DNS message header."""
_fields_ = [('id', ctypes.c_ushort),
('flag_qr', ctypes.c_ubyte, 1),
('opcode', ctypes.c_ubyte, 4),
('flag_aa', ctypes.c_ubyte, 1),
('flag_tc', ctypes.c_ubyte, 1),
('flag_rd', ctypes.c_ubyte, 1),
('flag_ra', ctypes.c_ubyte, 1),
('flag_z', ctypes.c_ubyte, 1),
('flag_ad', ctypes.c_ubyte, 1),
('flag_cd', ctypes.c_ubyte, 1),
('rcode', ctypes.c_ubyte, 4),
('questions', ctypes.c_ushort),
('answers', ctypes.c_ushort),
('authorities', ctypes.c_ushort),
('additionals', ctypes.c_ushort)]
class KnotProbeData(ctypes.Structure):
"""Libknot probe data unit."""
ADDR_MAX_SIZE = 16
QNAME_MAX_SIZE = 255
EDE_NONE = 65535
_fields_ = [('ip', ctypes.c_ubyte),
('proto', ctypes.c_ubyte),
('local_addr', ctypes.c_ubyte * ADDR_MAX_SIZE),
('local_port', ctypes.c_ushort),
('remote_addr', ctypes.c_ubyte * ADDR_MAX_SIZE),
('remote_port', ctypes.c_ushort),
('reply_hdr', KnotProbeDataDNSHdr),
('reply_size', ctypes.c_ushort),
('reply_rcode', ctypes.c_ushort),
('reply_ede', ctypes.c_ushort),
('tcp_rtt', ctypes.c_uint),
('edns_options', ctypes.c_uint),
('edns_payload', ctypes.c_ushort),
('edns_version', ctypes.c_ubyte),
('edns_present', ctypes.c_ubyte, 1),
('edns_flag_do', ctypes.c_ubyte, 1),
('_reserved_', ctypes.c_ubyte, 6),
('query_hdr', KnotProbeDataDNSHdr),
('query_size', ctypes.c_ushort),
('query_class', ctypes.c_ushort),
('query_type', ctypes.c_ushort),
('query_name_len', ctypes.c_ubyte),
('query_name', ctypes.c_ubyte * (QNAME_MAX_SIZE))]
def addr_str(self, addr: ctypes.c_ubyte * ADDR_MAX_SIZE) -> str:
"""Converts IPv4 or IPv6 address from binary to text form."""
if self.ip == 4:
buffer = ctypes.create_string_buffer(4)
ctypes.memmove(buffer, ctypes.addressof(addr), 4)
return socket.inet_ntop(socket.AF_INET, buffer)
else:
return socket.inet_ntop(socket.AF_INET6, addr)
def qname_str(self) -> str:
"""Returns QNAME in text form."""
string = str()
pos = 0
while pos < self.query_name_len:
label_len = self.query_name[pos]
if label_len == 0:
if self.query_name_len == 1:
string += "."
break
pos += 1
label_end = pos + label_len
while pos < label_end:
string += chr(self.query_name[pos])
pos += 1
string += "."
return string
def __str__(self) -> str:
"""Returns the data unit in a pre-formatted text form."""
return self.str()
def str(self, timestamp: bool = True, color: bool = True) -> str:
"""Returns the data unit in a pre-formatted text form with customization."""
RST = "\x1B[0m"
BOLD = "\x1B[1m"
UNDR = "\x1B[4m"
RED = "\x1B[31m"
GRN = "\x1B[32m"
ORG = "\x1B[33m"
YELW = "\x1B[93m"
MGNT = "\x1B[35m"
CYAN = "\x1B[36m"
def COL(string, color_str, active=color):
return str(string) if not active else color_str + str(string) + RST
string = str()
if timestamp:
string += "%s " % COL(datetime.datetime.now().time(), YELW)
if self.ip != 0:
string += "%s -> %s, " % (COL(self.addr_str(self.remote_addr), UNDR),
COL(self.addr_str(self.local_addr), UNDR))
string += "port %u -> %u " % (self.remote_port, self.local_port)
else:
string += "%s, " % COL("UNIX", UNDR)
if self.proto == KnotProbeDataProto.UDP:
string += COL("UDP", GRN)
elif self.proto == KnotProbeDataProto.TCP:
string += COL("TCP", RED)
else:
string += COL("QUIC", ORG)
if self.tcp_rtt > 0:
string += ", RTT %.2f ms" % (self.tcp_rtt / 1000)
string += "\n ID %u, " % self.query_hdr.id
if self.query_hdr.opcode == 0:
string += "QUERY"
elif self.query_hdr.opcode == 4:
string += COL("NOTIFY", MGNT)
elif self.query_hdr.opcode == 5:
string += COL("UPDATE", MGNT)
else:
string += COL("OPCODE%i" % self.query_hdr.opcode, MGNT)
string += ", "
string += COL("%s %s %s" % (self.qname_str(),
libknot.Knot.rclass_str(self.query_class),
libknot.Knot.rtype_str(self.query_type)), BOLD)
if self.edns_present == 1:
string += ", EDNS %i B" % self.edns_payload
if self.edns_flag_do == 1:
string += ", " + COL("DO", BOLD)
if (self.edns_options & (1 << 3)) != 0:
string += ", NSID"
if (self.edns_options & (1 << 8)) != 0:
string += ", ECS"
if (self.edns_options & (1 << 10)) != 0:
string += ", COOKIE"
string += ", " + COL("%u B" % self.query_size, CYAN)
if self.reply_size == 0:
string += " -> %s" % COL("DROPPED", RED)
return string
string += " -> %s" % COL(libknot.Knot.rcode_str(self.reply_rcode), BOLD)
if (self.reply_ede != libknot.probe.KnotProbeData.EDE_NONE):
string += ", EDE %u" % self.reply_ede
if self.reply_hdr.flag_aa != 0:
string += ", " + COL("AA", BOLD)
if self.reply_hdr.flag_tc != 0:
string += ", " + COL("TC", BOLD)
if self.reply_hdr.answers > 0:
string += ", %u ANS" % self.reply_hdr.answers
if self.reply_hdr.authorities > 0:
string += ", %u AUT" % self.reply_hdr.authorities
if self.reply_hdr.additionals > 0:
string += ", %u ADD" % self.reply_hdr.additionals
string += ", " + COL("%u B" % self.reply_size, CYAN)
return string
class KnotProbeDataArray(object):
"""Libknot probe data unit array."""
def __init__(self, size: int = 1) -> None:
"""Creates a data array of a given size."""
if size < 1 or size > 255:
raise ValueError
data_array = KnotProbeData * size
self.data = data_array()
self.capacity = size
self.used = 0
self.pos = 0
def __getitem__(self, i: int) -> KnotProbeData:
"""Returns a data unit at a specified position."""
if i < 0 or i >= self.capacity:
raise ValueError
return self.data[i]
def __len__(self) -> int:
"""Returns currently used size of the array."""
return self.used
def __iter__(self):
"""Initializes the array iterator."""
self.pos = 0
return self
def __next__(self) -> KnotProbeData:
"""Increments the array iterator."""
if self.used == 0 or self.pos == self.used:
raise StopIteration
else:
data = self.data[self.pos]
self.pos += 1
return data
class KnotProbe(object):
"""Libknot probe consumer interface."""
ALLOC = None
FREE = None
CONSUME = None
SET_CONSUMER = None
def __init__(self, path: str = "/run/knot", idx: int = 1) -> None:
"""Initializes a probe channel at a specified path with a channel index."""
if not KnotProbe.ALLOC:
libknot.Knot()
KnotProbe.ALLOC = libknot.Knot.LIBKNOT.knot_probe_alloc
KnotProbe.ALLOC.restype = ctypes.c_void_p
KnotProbe.FREE = libknot.Knot.LIBKNOT.knot_probe_free
KnotProbe.FREE.argtypes = [ctypes.c_void_p]
KnotProbe.CONSUME = libknot.Knot.LIBKNOT.knot_probe_consume
KnotProbe.CONSUME.restype = ctypes.c_int
KnotProbe.CONSUME.argtypes = [ctypes.c_void_p, ctypes.c_void_p, \
ctypes.c_ubyte, ctypes.c_int]
KnotProbe.SET_CONSUMER = libknot.Knot.LIBKNOT.knot_probe_set_consumer
KnotProbe.SET_CONSUMER.restype = ctypes.c_int
KnotProbe.SET_CONSUMER.argtypes = [ctypes.c_void_p, ctypes.c_char_p, \
ctypes.c_ushort]
self.obj = KnotProbe.ALLOC()
ret = KnotProbe.SET_CONSUMER(self.obj, path.encode(), idx)
if ret != 0:
err = libknot.Knot.STRERROR(ret)
raise RuntimeError(err.decode())
def __del__(self) -> None:
"""Deinitializes a probe channel."""
KnotProbe.FREE(self.obj)
def consume(self, data: KnotProbeDataArray, timeout: int = 1000) -> int:
'''Consumes data units from a channel and stores them in data array.
Returns the number of consumed data units.
'''
ret = KnotProbe.CONSUME(self.obj, data.data, data.capacity, timeout)
if ret < 0:
err = libknot.Knot.STRERROR(ret)
raise RuntimeError(err.decode())
data.used = ret
return ret
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