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|
#!/usr/local/bin/python3
import os
import socket
import struct
import sys
from ctypes import c_byte
from ctypes import c_char
from ctypes import c_int
from ctypes import c_long
from ctypes import c_uint32
from ctypes import c_ulong
from ctypes import c_ushort
from ctypes import sizeof
from ctypes import Structure
from typing import Dict
from typing import List
from typing import Optional
from typing import Union
def roundup2(val: int, num: int) -> int:
if val % num:
return (val | (num - 1)) + 1
else:
return val
class RtSockException(OSError):
pass
class RtConst:
RTM_VERSION = 5
ALIGN = sizeof(c_long)
AF_INET = socket.AF_INET
AF_INET6 = socket.AF_INET6
AF_LINK = socket.AF_LINK
RTA_DST = 0x1
RTA_GATEWAY = 0x2
RTA_NETMASK = 0x4
RTA_GENMASK = 0x8
RTA_IFP = 0x10
RTA_IFA = 0x20
RTA_AUTHOR = 0x40
RTA_BRD = 0x80
RTM_ADD = 1
RTM_DELETE = 2
RTM_CHANGE = 3
RTM_GET = 4
RTF_UP = 0x1
RTF_GATEWAY = 0x2
RTF_HOST = 0x4
RTF_REJECT = 0x8
RTF_DYNAMIC = 0x10
RTF_MODIFIED = 0x20
RTF_DONE = 0x40
RTF_XRESOLVE = 0x200
RTF_LLINFO = 0x400
RTF_LLDATA = 0x400
RTF_STATIC = 0x800
RTF_BLACKHOLE = 0x1000
RTF_PROTO2 = 0x4000
RTF_PROTO1 = 0x8000
RTF_PROTO3 = 0x40000
RTF_FIXEDMTU = 0x80000
RTF_PINNED = 0x100000
RTF_LOCAL = 0x200000
RTF_BROADCAST = 0x400000
RTF_MULTICAST = 0x800000
RTF_STICKY = 0x10000000
RTF_RNH_LOCKED = 0x40000000
RTF_GWFLAG_COMPAT = 0x80000000
RTV_MTU = 0x1
RTV_HOPCOUNT = 0x2
RTV_EXPIRE = 0x4
RTV_RPIPE = 0x8
RTV_SPIPE = 0x10
RTV_SSTHRESH = 0x20
RTV_RTT = 0x40
RTV_RTTVAR = 0x80
RTV_WEIGHT = 0x100
@staticmethod
def get_props(prefix: str) -> List[str]:
return [n for n in dir(RtConst) if n.startswith(prefix)]
@staticmethod
def get_name(prefix: str, value: int) -> str:
props = RtConst.get_props(prefix)
for prop in props:
if getattr(RtConst, prop) == value:
return prop
return "U:{}:{}".format(prefix, value)
@staticmethod
def get_bitmask_map(prefix: str, value: int) -> Dict[int, str]:
props = RtConst.get_props(prefix)
propmap = {getattr(RtConst, prop): prop for prop in props}
v = 1
ret = {}
while value:
if v & value:
if v in propmap:
ret[v] = propmap[v]
else:
ret[v] = hex(v)
value -= v
v *= 2
return ret
@staticmethod
def get_bitmask_str(prefix: str, value: int) -> str:
bmap = RtConst.get_bitmask_map(prefix, value)
return ",".join([v for k, v in bmap.items()])
class RtMetrics(Structure):
_fields_ = [
("rmx_locks", c_ulong),
("rmx_mtu", c_ulong),
("rmx_hopcount", c_ulong),
("rmx_expire", c_ulong),
("rmx_recvpipe", c_ulong),
("rmx_sendpipe", c_ulong),
("rmx_ssthresh", c_ulong),
("rmx_rtt", c_ulong),
("rmx_rttvar", c_ulong),
("rmx_pksent", c_ulong),
("rmx_weight", c_ulong),
("rmx_nhidx", c_ulong),
("rmx_filler", c_ulong * 2),
]
class RtMsgHdr(Structure):
_fields_ = [
("rtm_msglen", c_ushort),
("rtm_version", c_byte),
("rtm_type", c_byte),
("rtm_index", c_ushort),
("_rtm_spare1", c_ushort),
("rtm_flags", c_int),
("rtm_addrs", c_int),
("rtm_pid", c_int),
("rtm_seq", c_int),
("rtm_errno", c_int),
("rtm_fmask", c_int),
("rtm_inits", c_ulong),
("rtm_rmx", RtMetrics),
]
class SockaddrIn(Structure):
_fields_ = [
("sin_len", c_byte),
("sin_family", c_byte),
("sin_port", c_ushort),
("sin_addr", c_uint32),
("sin_zero", c_char * 8),
]
class SockaddrIn6(Structure):
_fields_ = [
("sin6_len", c_byte),
("sin6_family", c_byte),
("sin6_port", c_ushort),
("sin6_flowinfo", c_uint32),
("sin6_addr", c_byte * 16),
("sin6_scope_id", c_uint32),
]
class SockaddrDl(Structure):
_fields_ = [
("sdl_len", c_byte),
("sdl_family", c_byte),
("sdl_index", c_ushort),
("sdl_type", c_byte),
("sdl_nlen", c_byte),
("sdl_alen", c_byte),
("sdl_slen", c_byte),
("sdl_data", c_byte * 8),
]
class SaHelper(object):
@staticmethod
def is_ipv6(ip: str) -> bool:
return ":" in ip
@staticmethod
def ip_sa(ip: str, scopeid: int = 0) -> bytes:
if SaHelper.is_ipv6(ip):
return SaHelper.ip6_sa(ip, scopeid)
else:
return SaHelper.ip4_sa(ip)
@staticmethod
def ip4_sa(ip: str) -> bytes:
addr_int = int.from_bytes(socket.inet_pton(2, ip), sys.byteorder)
sin = SockaddrIn(sizeof(SockaddrIn), socket.AF_INET, 0, addr_int)
return bytes(sin)
@staticmethod
def ip6_sa(ip6: str, scopeid: int) -> bytes:
addr_bytes = (c_byte * 16)()
for i, b in enumerate(socket.inet_pton(socket.AF_INET6, ip6)):
addr_bytes[i] = b
sin6 = SockaddrIn6(
sizeof(SockaddrIn6), socket.AF_INET6, 0, 0, addr_bytes, scopeid
)
return bytes(sin6)
@staticmethod
def link_sa(ifindex: int = 0, iftype: int = 0) -> bytes:
sa = SockaddrDl(sizeof(SockaddrDl), socket.AF_LINK, c_ushort(ifindex), iftype)
return bytes(sa)
@staticmethod
def pxlen4_sa(pxlen: int) -> bytes:
return SaHelper.ip_sa(SaHelper.pxlen_to_ip4(pxlen))
@staticmethod
def pxlen_to_ip4(pxlen: int) -> str:
if pxlen == 32:
return "255.255.255.255"
else:
addr = 0xFFFFFFFF - ((1 << (32 - pxlen)) - 1)
addr_bytes = struct.pack("!I", addr)
return socket.inet_ntop(socket.AF_INET, addr_bytes)
@staticmethod
def pxlen6_sa(pxlen: int) -> bytes:
return SaHelper.ip_sa(SaHelper.pxlen_to_ip6(pxlen))
@staticmethod
def pxlen_to_ip6(pxlen: int) -> str:
ip6_b = [0] * 16
start = 0
while pxlen > 8:
ip6_b[start] = 0xFF
pxlen -= 8
start += 1
ip6_b[start] = 0xFF - ((1 << (8 - pxlen)) - 1)
return socket.inet_ntop(socket.AF_INET6, bytes(ip6_b))
@staticmethod
def print_sa_inet(sa: bytes):
if len(sa) < 8:
raise RtSockException("IPv4 sa size too small: {}".format(len(sa)))
addr = socket.inet_ntop(socket.AF_INET, sa[4:8])
return "{}".format(addr)
@staticmethod
def print_sa_inet6(sa: bytes):
if len(sa) < sizeof(SockaddrIn6):
raise RtSockException("IPv6 sa size too small: {}".format(len(sa)))
addr = socket.inet_ntop(socket.AF_INET6, sa[8:24])
scopeid = struct.unpack(">I", sa[24:28])[0]
return "{} scopeid {}".format(addr, scopeid)
@staticmethod
def print_sa_link(sa: bytes, hd: Optional[bool] = True):
if len(sa) < sizeof(SockaddrDl):
raise RtSockException("LINK sa size too small: {}".format(len(sa)))
sdl = SockaddrDl.from_buffer_copy(sa)
if sdl.sdl_index:
ifindex = "link#{} ".format(sdl.sdl_index)
else:
ifindex = ""
if sdl.sdl_nlen:
iface_offset = 8
if sdl.sdl_nlen + iface_offset > len(sa):
raise RtSockException(
"LINK sa sdl_nlen {} > total len {}".format(sdl.sdl_nlen, len(sa))
)
ifname = "ifname:{} ".format(
bytes.decode(sa[iface_offset : iface_offset + sdl.sdl_nlen])
)
else:
ifname = ""
return "{}{}".format(ifindex, ifname)
@staticmethod
def print_sa_unknown(sa: bytes):
return "unknown_type:{}".format(sa[1])
@classmethod
def print_sa(cls, sa: bytes, hd: Optional[bool] = False):
if sa[0] != len(sa):
raise Exception("sa size {} != buffer size {}".format(sa[0], len(sa)))
if len(sa) < 2:
raise Exception(
"sa type {} too short: {}".format(
RtConst.get_name("AF_", sa[1]), len(sa)
)
)
if sa[1] == socket.AF_INET:
text = cls.print_sa_inet(sa)
elif sa[1] == socket.AF_INET6:
text = cls.print_sa_inet6(sa)
elif sa[1] == socket.AF_LINK:
text = cls.print_sa_link(sa)
else:
text = cls.print_sa_unknown(sa)
if hd:
dump = " [{!r}]".format(sa)
else:
dump = ""
return "{}{}".format(text, dump)
class BaseRtsockMessage(object):
def __init__(self, rtm_type):
self.rtm_type = rtm_type
self.sa = SaHelper()
@staticmethod
def print_rtm_type(rtm_type):
return RtConst.get_name("RTM_", rtm_type)
@property
def rtm_type_str(self):
return self.print_rtm_type(self.rtm_type)
class RtsockRtMessage(BaseRtsockMessage):
messages = [
RtConst.RTM_ADD,
RtConst.RTM_DELETE,
RtConst.RTM_CHANGE,
RtConst.RTM_GET,
]
def __init__(self, rtm_type, rtm_seq=1, dst_sa=None, mask_sa=None):
super().__init__(rtm_type)
self.rtm_flags = 0
self.rtm_seq = rtm_seq
self._attrs = {}
self.rtm_errno = 0
self.rtm_pid = 0
self.rtm_inits = 0
self.rtm_rmx = RtMetrics()
self._orig_data = None
if dst_sa:
self.add_sa_attr(RtConst.RTA_DST, dst_sa)
if mask_sa:
self.add_sa_attr(RtConst.RTA_NETMASK, mask_sa)
def add_sa_attr(self, attr_type, attr_bytes: bytes):
self._attrs[attr_type] = attr_bytes
def add_ip_attr(self, attr_type, ip_addr: str, scopeid: int = 0):
if ":" in ip_addr:
self.add_ip6_attr(attr_type, ip_addr, scopeid)
else:
self.add_ip4_attr(attr_type, ip_addr)
def add_ip4_attr(self, attr_type, ip: str):
self.add_sa_attr(attr_type, self.sa.ip_sa(ip))
def add_ip6_attr(self, attr_type, ip6: str, scopeid: int):
self.add_sa_attr(attr_type, self.sa.ip6_sa(ip6, scopeid))
def add_link_attr(self, attr_type, ifindex: Optional[int] = 0):
self.add_sa_attr(attr_type, self.sa.link_sa(ifindex))
def get_sa(self, attr_type) -> bytes:
return self._attrs.get(attr_type)
def print_message(self):
# RTM_GET: Report Metrics: len 272, pid: 87839, seq 1, errno 0, flags:<UP,GATEWAY,DONE,STATIC>
if self._orig_data:
rtm_len = len(self._orig_data)
else:
rtm_len = len(bytes(self))
print(
"{}: len {}, pid: {}, seq {}, errno {}, flags: <{}>".format(
self.rtm_type_str,
rtm_len,
self.rtm_pid,
self.rtm_seq,
self.rtm_errno,
RtConst.get_bitmask_str("RTF_", self.rtm_flags),
)
)
rtm_addrs = sum(list(self._attrs.keys()))
print("Addrs: <{}>".format(RtConst.get_bitmask_str("RTA_", rtm_addrs)))
for attr in sorted(self._attrs.keys()):
sa_data = SaHelper.print_sa(self._attrs[attr])
print(" {}: {}".format(RtConst.get_name("RTA_", attr), sa_data))
def print_in_message(self):
print("vvvvvvvv IN vvvvvvvv")
self.print_message()
print()
def verify_sa_inet(self, sa_data):
if len(sa_data) < 8:
raise Exception("IPv4 sa size too small: {}".format(sa_data))
if sa_data[0] > len(sa_data):
raise Exception(
"IPv4 sin_len too big: {} vs sa size {}: {}".format(
sa_data[0], len(sa_data), sa_data
)
)
sin = SockaddrIn.from_buffer_copy(sa_data)
assert sin.sin_port == 0
assert sin.sin_zero == [0] * 8
def compare_sa(self, sa_type, sa_data):
if len(sa_data) < 4:
sa_type_name = RtConst.get_name("RTA_", sa_type)
raise Exception(
"sa_len for type {} too short: {}".format(sa_type_name, len(sa_data))
)
our_sa = self._attrs[sa_type]
assert SaHelper.print_sa(sa_data) == SaHelper.print_sa(our_sa)
assert len(sa_data) == len(our_sa)
assert sa_data == our_sa
def verify(self, rtm_type: int, rtm_sa):
assert self.rtm_type_str == self.print_rtm_type(rtm_type)
assert self.rtm_errno == 0
hdr = RtMsgHdr.from_buffer_copy(self._orig_data)
assert hdr._rtm_spare1 == 0
for sa_type, sa_data in rtm_sa.items():
if sa_type not in self._attrs:
sa_type_name = RtConst.get_name("RTA_", sa_type)
raise Exception("SA type {} not present".format(sa_type_name))
self.compare_sa(sa_type, sa_data)
@classmethod
def from_bytes(cls, data: bytes):
if len(data) < sizeof(RtMsgHdr):
raise Exception(
"messages size {} is less than expected {}".format(
len(data), sizeof(RtMsgHdr)
)
)
hdr = RtMsgHdr.from_buffer_copy(data)
self = cls(hdr.rtm_type)
self.rtm_flags = hdr.rtm_flags
self.rtm_seq = hdr.rtm_seq
self.rtm_errno = hdr.rtm_errno
self.rtm_pid = hdr.rtm_pid
self.rtm_inits = hdr.rtm_inits
self.rtm_rmx = hdr.rtm_rmx
self._orig_data = data
off = sizeof(RtMsgHdr)
v = 1
addrs_mask = hdr.rtm_addrs
while addrs_mask:
if addrs_mask & v:
addrs_mask -= v
if off + data[off] > len(data):
raise Exception(
"SA sizeof for {} > total message length: {}+{} > {}".format(
RtConst.get_name("RTA_", v), off, data[off], len(data)
)
)
self._attrs[v] = data[off : off + data[off]]
off += roundup2(data[off], RtConst.ALIGN)
v *= 2
return self
def __bytes__(self):
sz = sizeof(RtMsgHdr)
addrs_mask = 0
for k, v in self._attrs.items():
sz += roundup2(len(v), RtConst.ALIGN)
addrs_mask += k
hdr = RtMsgHdr(
rtm_msglen=sz,
rtm_version=RtConst.RTM_VERSION,
rtm_type=self.rtm_type,
rtm_flags=self.rtm_flags,
rtm_seq=self.rtm_seq,
rtm_addrs=addrs_mask,
rtm_inits=self.rtm_inits,
rtm_rmx=self.rtm_rmx,
)
buf = bytearray(sz)
buf[0 : sizeof(RtMsgHdr)] = hdr
off = sizeof(RtMsgHdr)
for attr in sorted(self._attrs.keys()):
v = self._attrs[attr]
sa_len = len(v)
buf[off : off + sa_len] = v
off += roundup2(len(v), RtConst.ALIGN)
return bytes(buf)
class Rtsock:
def __init__(self):
self.socket = self._setup_rtsock()
self.rtm_seq = 1
self.msgmap = self.build_msgmap()
def build_msgmap(self):
classes = [RtsockRtMessage]
xmap = {}
for cls in classes:
for message in cls.messages:
xmap[message] = cls
return xmap
def get_seq(self):
ret = self.rtm_seq
self.rtm_seq += 1
return ret
def get_weight(self, weight) -> int:
if weight:
return weight
else:
return 1 # RT_DEFAULT_WEIGHT
def new_rtm_any(self, msg_type, prefix: str, gw: Union[str, bytes]):
px = prefix.split("/")
addr_sa = SaHelper.ip_sa(px[0])
if len(px) > 1:
pxlen = int(px[1])
if SaHelper.is_ipv6(px[0]):
mask_sa = SaHelper.pxlen6_sa(pxlen)
else:
mask_sa = SaHelper.pxlen4_sa(pxlen)
else:
mask_sa = None
msg = RtsockRtMessage(msg_type, self.get_seq(), addr_sa, mask_sa)
if isinstance(gw, bytes):
msg.add_sa_attr(RtConst.RTA_GATEWAY, gw)
else:
# String
msg.add_ip_attr(RtConst.RTA_GATEWAY, gw)
return msg
def new_rtm_add(self, prefix: str, gw: Union[str, bytes]):
return self.new_rtm_any(RtConst.RTM_ADD, prefix, gw)
def new_rtm_del(self, prefix: str, gw: Union[str, bytes]):
return self.new_rtm_any(RtConst.RTM_DELETE, prefix, gw)
def new_rtm_change(self, prefix: str, gw: Union[str, bytes]):
return self.new_rtm_any(RtConst.RTM_CHANGE, prefix, gw)
def _setup_rtsock(self) -> socket.socket:
s = socket.socket(socket.AF_ROUTE, socket.SOCK_RAW, socket.AF_UNSPEC)
s.setsockopt(socket.SOL_SOCKET, socket.SO_USELOOPBACK, 1)
return s
def print_hd(self, data: bytes):
width = 16
print("==========================================")
for chunk in [data[i : i + width] for i in range(0, len(data), width)]:
for b in chunk:
print("0x{:02X} ".format(b), end="")
print()
print()
def write_message(self, msg):
print("vvvvvvvv OUT vvvvvvvv")
msg.print_message()
print()
msg_bytes = bytes(msg)
ret = os.write(self.socket.fileno(), msg_bytes)
if ret != -1:
assert ret == len(msg_bytes)
def parse_message(self, data: bytes):
if len(data) < 4:
raise OSError("Short read from rtsock: {} bytes".format(len(data)))
rtm_type = data[4]
if rtm_type not in self.msgmap:
return None
def write_data(self, data: bytes):
self.socket.send(data)
def read_data(self, seq: Optional[int] = None) -> bytes:
while True:
data = self.socket.recv(4096)
if seq is None:
break
if len(data) > sizeof(RtMsgHdr):
hdr = RtMsgHdr.from_buffer_copy(data)
if hdr.rtm_seq == seq:
break
return data
def read_message(self) -> bytes:
data = self.read_data()
return self.parse_message(data)
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