#!/usr/bin/python
#
# Copyright 2015 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Partial Python implementation of sock_diag functionality."""
# pylint: disable=g-bad-todo
import errno
from socket import * # pylint: disable=wildcard-import
import struct
import cstruct
import net_test
import netlink
### Base netlink constants. See include/uapi/linux/netlink.h.
NETLINK_SOCK_DIAG = 4
### sock_diag constants. See include/uapi/linux/sock_diag.h.
# Message types.
SOCK_DIAG_BY_FAMILY = 20
SOCK_DESTROY = 21
### inet_diag_constants. See include/uapi/linux/inet_diag.h
# Message types.
TCPDIAG_GETSOCK = 18
# Request attributes.
INET_DIAG_REQ_BYTECODE = 1
# Extensions.
INET_DIAG_NONE = 0
INET_DIAG_MEMINFO = 1
INET_DIAG_INFO = 2
INET_DIAG_VEGASINFO = 3
INET_DIAG_CONG = 4
INET_DIAG_TOS = 5
INET_DIAG_TCLASS = 6
INET_DIAG_SKMEMINFO = 7
INET_DIAG_SHUTDOWN = 8
INET_DIAG_DCTCPINFO = 9
# Bytecode operations.
INET_DIAG_BC_NOP = 0
INET_DIAG_BC_JMP = 1
INET_DIAG_BC_S_GE = 2
INET_DIAG_BC_S_LE = 3
INET_DIAG_BC_D_GE = 4
INET_DIAG_BC_D_LE = 5
INET_DIAG_BC_AUTO = 6
INET_DIAG_BC_S_COND = 7
INET_DIAG_BC_D_COND = 8
# Data structure formats.
# These aren't constants, they're classes. So, pylint: disable=invalid-name
InetDiagSockId = cstruct.Struct(
"InetDiagSockId", "!HH16s16sI8s", "sport dport src dst iface cookie")
InetDiagReqV2 = cstruct.Struct(
"InetDiagReqV2", "=BBBxIS", "family protocol ext states id",
[InetDiagSockId])
InetDiagMsg = cstruct.Struct(
"InetDiagMsg", "=BBBBSLLLLL",
"family state timer retrans id expires rqueue wqueue uid inode",
[InetDiagSockId])
InetDiagMeminfo = cstruct.Struct(
"InetDiagMeminfo", "=IIII", "rmem wmem fmem tmem")
InetDiagBcOp = cstruct.Struct("InetDiagBcOp", "BBH", "code yes no")
InetDiagHostcond = cstruct.Struct("InetDiagHostcond", "=BBxxi",
"family prefix_len port")
SkMeminfo = cstruct.Struct(
"SkMeminfo", "=IIIIIIII",
"rmem_alloc rcvbuf wmem_alloc sndbuf fwd_alloc wmem_queued optmem backlog")
TcpInfo = cstruct.Struct(
"TcpInfo", "=BBBBBBBxIIIIIIIIIIIIIIIIIIIIIIII",
"state ca_state retransmits probes backoff options wscale "
"rto ato snd_mss rcv_mss "
"unacked sacked lost retrans fackets "
"last_data_sent last_ack_sent last_data_recv last_ack_recv "
"pmtu rcv_ssthresh rtt rttvar snd_ssthresh snd_cwnd advmss reordering "
"rcv_rtt rcv_space "
"total_retrans") # As of linux 3.13, at least.
TCP_TIME_WAIT = 6
ALL_NON_TIME_WAIT = 0xffffffff & ~(1 << TCP_TIME_WAIT)
class SockDiag(netlink.NetlinkSocket):
FAMILY = NETLINK_SOCK_DIAG
NL_DEBUG = []
def _Decode(self, command, msg, nla_type, nla_data):
"""Decodes netlink attributes to Python types."""
if msg.family == AF_INET or msg.family == AF_INET6:
name = self._GetConstantName(__name__, nla_type, "INET_DIAG")
else:
# Don't know what this is. Leave it as an integer.
name = nla_type
if name in ["INET_DIAG_SHUTDOWN", "INET_DIAG_TOS", "INET_DIAG_TCLASS"]:
data = ord(nla_data)
elif name == "INET_DIAG_CONG":
data = nla_data.strip("\x00")
elif name == "INET_DIAG_MEMINFO":
data = InetDiagMeminfo(nla_data)
elif name == "INET_DIAG_INFO":
# TODO: Catch the exception and try something else if it's not TCP.
data = TcpInfo(nla_data)
elif name == "INET_DIAG_SKMEMINFO":
data = SkMeminfo(nla_data)
else:
data = nla_data
return name, data
def MaybeDebugCommand(self, command, data):
name = self._GetConstantName(__name__, command, "SOCK_")
if "ALL" not in self.NL_DEBUG and "SOCK" not in self.NL_DEBUG:
return
parsed = self._ParseNLMsg(data, InetDiagReqV2)
print "%s %s" % (name, str(parsed))
@staticmethod
def _EmptyInetDiagSockId():
return InetDiagSockId(("\x00" * len(InetDiagSockId)))
def PackBytecode(self, instructions):
"""Compiles instructions to inet_diag bytecode.
The input is a list of (INET_DIAG_BC_xxx, yes, no, arg) tuples, where yes
and no are relative jump offsets measured in instructions. The yes branch
is taken if the instruction matches.
To accept, jump 1 past the last instruction. To reject, jump 2 past the
last instruction.
The target of a no jump is only valid if it is reachable by following
only yes jumps from the first instruction - see inet_diag_bc_audit and
valid_cc. This means that if cond1 and cond2 are two mutually exclusive
filter terms, it is not possible to implement cond1 OR cond2 using:
...
cond1 2 1 arg
cond2 1 2 arg
accept
reject
but only using:
...
cond1 1 2 arg
jmp 1 2
cond2 1 2 arg
accept
reject
The jmp instruction ignores yes and always jumps to no, but yes must be 1
or the bytecode won't validate. It doesn't have to be jmp - any instruction
that is guaranteed not to match on real data will do.
Args:
instructions: list of instruction tuples
Returns:
A string, the raw bytecode.
"""
args = []
positions = [0]
for op, yes, no, arg in instructions:
if yes <= 0 or no <= 0:
raise ValueError("Jumps must be > 0")
if op in [INET_DIAG_BC_NOP, INET_DIAG_BC_JMP, INET_DIAG_BC_AUTO]:
arg = ""
elif op in [INET_DIAG_BC_S_GE, INET_DIAG_BC_S_LE,
INET_DIAG_BC_D_GE, INET_DIAG_BC_D_LE]:
arg = "\x00\x00" + struct.pack("=H", arg)
elif op in [INET_DIAG_BC_S_COND, INET_DIAG_BC_D_COND]:
addr, prefixlen, port = arg
family = AF_INET6 if ":" in addr else AF_INET
addr = inet_pton(family, addr)
arg = InetDiagHostcond((family, prefixlen, port)).Pack() + addr
else:
raise ValueError("Unsupported opcode %d" % op)
args.append(arg)
length = len(InetDiagBcOp) + len(arg)
positions.append(positions[-1] + length)
# Reject label.
positions.append(positions[-1] + 4) # Why 4? Because the kernel uses 4.
assert len(args) == len(instructions) == len(positions) - 2
# print positions
packed = ""
for i, (op, yes, no, arg) in enumerate(instructions):
yes = positions[i + yes] - positions[i]
no = positions[i + no] - positions[i]
instruction = InetDiagBcOp((op, yes, no)).Pack() + args[i]
#print "%3d: %d %3d %3d %s %s" % (positions[i], op, yes, no,
# arg, instruction.encode("hex"))
packed += instruction
#print
return packed
def Dump(self, diag_req, bytecode=""):
out = self._Dump(SOCK_DIAG_BY_FAMILY, diag_req, InetDiagMsg, bytecode)
return out
def DumpAllInetSockets(self, protocol, bytecode, sock_id=None, ext=0,
states=ALL_NON_TIME_WAIT):
"""Dumps IPv4 or IPv6 sockets matching the specified parameters."""
# DumpSockets(AF_UNSPEC) does not result in dumping all inet sockets, it
# results in ENOENT.
if sock_id is None:
sock_id = self._EmptyInetDiagSockId()
if bytecode:
bytecode = self._NlAttr(INET_DIAG_REQ_BYTECODE, bytecode)
sockets = []
for family in [AF_INET, AF_INET6]:
diag_req = InetDiagReqV2((family, protocol, ext, states, sock_id))
sockets += self.Dump(diag_req, bytecode)
return sockets
@staticmethod
def GetRawAddress(family, addr):
"""Fetches the source address from an InetDiagMsg."""
addrlen = {AF_INET:4, AF_INET6: 16}[family]
return inet_ntop(family, addr[:addrlen])
@staticmethod
def GetSourceAddress(diag_msg):
"""Fetches the source address from an InetDiagMsg."""
return SockDiag.GetRawAddress(diag_msg.family, diag_msg.id.src)
@staticmethod
def GetDestinationAddress(diag_msg):
"""Fetches the source address from an InetDiagMsg."""
return SockDiag.GetRawAddress(diag_msg.family, diag_msg.id.dst)
@staticmethod
def RawAddress(addr):
"""Converts an IP address string to binary format."""
family = AF_INET6 if ":" in addr else AF_INET
return inet_pton(family, addr)
@staticmethod
def PaddedAddress(addr):
"""Converts an IP address string to binary format for InetDiagSockId."""
padded = SockDiag.RawAddress(addr)
if len(padded) < 16:
padded += "\x00" * (16 - len(padded))
return padded
@staticmethod
def DiagReqFromSocket(s):
"""Creates an InetDiagReqV2 that matches the specified socket."""
family = s.getsockopt(net_test.SOL_SOCKET, net_test.SO_DOMAIN)
protocol = s.getsockopt(net_test.SOL_SOCKET, net_test.SO_PROTOCOL)
if net_test.LINUX_VERSION >= (3, 8):
iface = s.getsockopt(SOL_SOCKET, net_test.SO_BINDTODEVICE,
net_test.IFNAMSIZ)
iface = GetInterfaceIndex(iface) if iface else 0
else:
iface = 0
src, sport = s.getsockname()[:2]
try:
dst, dport = s.getpeername()[:2]
except error, e:
if e.errno == errno.ENOTCONN:
dport = 0
dst = "::" if family == AF_INET6 else "0.0.0.0"
else:
raise e
src = SockDiag.PaddedAddress(src)
dst = SockDiag.PaddedAddress(dst)
sock_id = InetDiagSockId((sport, dport, src, dst, iface, "\x00" * 8))
return InetDiagReqV2((family, protocol, 0, 0xffffffff, sock_id))
def FindSockDiagFromReq(self, req):
for diag_msg, attrs in self.Dump(req):
return diag_msg
raise ValueError("Dump of %s returned no sockets" % req)
def FindSockDiagFromFd(self, s):
"""Gets an InetDiagMsg from the kernel for the specified socket."""
req = self.DiagReqFromSocket(s)
return self.FindSockDiagFromReq(req)
def GetSockDiag(self, req):
"""Gets an InetDiagMsg from the kernel for the specified request."""
self._SendNlRequest(SOCK_DIAG_BY_FAMILY, req.Pack(), netlink.NLM_F_REQUEST)
return self._GetMsg(InetDiagMsg)[0]
@staticmethod
def DiagReqFromDiagMsg(d, protocol):
"""Constructs a diag_req from a diag_msg the kernel has given us."""
return InetDiagReqV2((d.family, protocol, 0, 1 << d.state, d.id))
def CloseSocket(self, req):
self._SendNlRequest(SOCK_DESTROY, req.Pack(),
netlink.NLM_F_REQUEST | netlink.NLM_F_ACK)
def CloseSocketFromFd(self, s):
diag_msg = self.FindSockDiagFromFd(s)
protocol = s.getsockopt(SOL_SOCKET, net_test.SO_PROTOCOL)
req = self.DiagReqFromDiagMsg(diag_msg, protocol)
return self.CloseSocket(req)
if __name__ == "__main__":
n = SockDiag()
n.DEBUG = True
bytecode = ""
sock_id = n._EmptyInetDiagSockId()
sock_id.dport = 443
ext = 1 << (INET_DIAG_TOS - 1) | 1 << (INET_DIAG_TCLASS - 1)
states = 0xffffffff
diag_msgs = n.DumpAllInetSockets(IPPROTO_TCP, "",
sock_id=sock_id, ext=ext, states=states)
print diag_msgs