1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
|
import json
from ctypes import *
import sys
NFTABLES_VERSION = "0.1"
class Nftables:
"""A class representing libnftables interface"""
debug_flags = {
"scanner": 0x1,
"parser": 0x2,
"eval": 0x4,
"netlink": 0x8,
"mnl": 0x10,
"proto-ctx": 0x20,
"segtree": 0x40,
}
numeric_levels = {
"none": 0,
"addr": 1,
"port": 2,
"all": 3,
}
def __init__(self, sofile="libnftables.so"):
"""Instantiate a new Nftables class object.
Accepts a shared object file to open, by default standard search path
is searched for a file named 'libnftables.so'.
After loading the library using ctypes module, a new nftables context
is requested from the library and buffering of output and error streams
is turned on.
"""
lib = cdll.LoadLibrary(sofile)
### API function definitions
self.nft_ctx_new = lib.nft_ctx_new
self.nft_ctx_new.restype = c_void_p
self.nft_ctx_new.argtypes = [c_int]
self.nft_ctx_output_get_handle = lib.nft_ctx_output_get_handle
self.nft_ctx_output_get_handle.restype = c_bool
self.nft_ctx_output_get_handle.argtypes = [c_void_p]
self.nft_ctx_output_set_handle = lib.nft_ctx_output_set_handle
self.nft_ctx_output_set_handle.argtypes = [c_void_p, c_bool]
self.nft_ctx_output_get_echo = lib.nft_ctx_output_get_echo
self.nft_ctx_output_get_echo.restype = c_bool
self.nft_ctx_output_get_echo.argtypes = [c_void_p]
self.nft_ctx_output_set_echo = lib.nft_ctx_output_set_echo
self.nft_ctx_output_set_echo.argtypes = [c_void_p, c_bool]
self.nft_ctx_output_get_numeric = lib.nft_ctx_output_get_numeric
self.nft_ctx_output_get_numeric.restype = c_int
self.nft_ctx_output_get_numeric.argtypes = [c_void_p]
self.nft_ctx_output_set_numeric = lib.nft_ctx_output_set_numeric
self.nft_ctx_output_set_numeric.argtypes = [c_void_p, c_int]
self.nft_ctx_output_get_stateless = lib.nft_ctx_output_get_stateless
self.nft_ctx_output_get_stateless.restype = c_bool
self.nft_ctx_output_get_stateless.argtypes = [c_void_p]
self.nft_ctx_output_set_stateless = lib.nft_ctx_output_set_stateless
self.nft_ctx_output_set_stateless.argtypes = [c_void_p, c_bool]
self.nft_ctx_output_get_json = lib.nft_ctx_output_get_json
self.nft_ctx_output_get_json.restype = c_bool
self.nft_ctx_output_get_json.argtypes = [c_void_p]
self.nft_ctx_output_set_json = lib.nft_ctx_output_set_json
self.nft_ctx_output_set_json.argtypes = [c_void_p, c_bool]
self.nft_ctx_output_get_debug = lib.nft_ctx_output_get_debug
self.nft_ctx_output_get_debug.restype = c_int
self.nft_ctx_output_get_debug.argtypes = [c_void_p]
self.nft_ctx_output_set_debug = lib.nft_ctx_output_set_debug
self.nft_ctx_output_set_debug.argtypes = [c_void_p, c_int]
self.nft_ctx_buffer_output = lib.nft_ctx_buffer_output
self.nft_ctx_buffer_output.restype = c_int
self.nft_ctx_buffer_output.argtypes = [c_void_p]
self.nft_ctx_get_output_buffer = lib.nft_ctx_get_output_buffer
self.nft_ctx_get_output_buffer.restype = c_char_p
self.nft_ctx_get_output_buffer.argtypes = [c_void_p]
self.nft_ctx_buffer_error = lib.nft_ctx_buffer_error
self.nft_ctx_buffer_error.restype = c_int
self.nft_ctx_buffer_error.argtypes = [c_void_p]
self.nft_ctx_get_error_buffer = lib.nft_ctx_get_error_buffer
self.nft_ctx_get_error_buffer.restype = c_char_p
self.nft_ctx_get_error_buffer.argtypes = [c_void_p]
self.nft_run_cmd_from_buffer = lib.nft_run_cmd_from_buffer
self.nft_run_cmd_from_buffer.restype = c_int
self.nft_run_cmd_from_buffer.argtypes = [c_void_p, c_char_p]
self.nft_ctx_free = lib.nft_ctx_free
lib.nft_ctx_free.argtypes = [c_void_p]
# initialize libnftables context
self.__ctx = self.nft_ctx_new(0)
self.nft_ctx_buffer_output(self.__ctx)
self.nft_ctx_buffer_error(self.__ctx)
def get_handle_output(self):
"""Get the current state of handle output.
Returns a boolean indicating whether handle output is active or not.
"""
return self.nft_ctx_output_get_handle(self.__ctx)
def set_handle_output(self, val):
"""Enable or disable handle output.
Accepts a boolean turning handle output on or off.
Returns the previous value.
"""
old = self.get_handle_output()
self.nft_ctx_output_set_handle(self.__ctx, val)
return old
def get_echo_output(self):
"""Get the current state of echo output.
Returns a boolean indicating whether echo output is active or not.
"""
return self.nft_ctx_output_get_echo(self.__ctx)
def set_echo_output(self, val):
"""Enable or disable echo output.
Accepts a boolean turning echo output on or off.
Returns the previous value.
"""
old = self.get_echo_output()
self.nft_ctx_output_set_echo(self.__ctx, val)
return old
def get_numeric_output(self):
"""Get the current state of numeric output.
Returns a boolean indicating whether boolean output is active or not.
"""
return self.nft_ctx_output_get_numeric(self.__ctx)
def set_numeric_output(self, val):
"""Enable or disable numeric output.
Accepts a boolean turning numeric output on or off.
Returns the previous value.
"""
old = self.get_numeric_output()
if type(val) is str:
val = self.numeric_levels[val]
self.nft_ctx_output_set_numeric(self.__ctx, val)
return old
def get_stateless_output(self):
"""Get the current state of stateless output.
Returns a boolean indicating whether stateless output is active or not.
"""
return self.nft_ctx_output_get_stateless(self.__ctx)
def set_stateless_output(self, val):
"""Enable or disable stateless output.
Accepts a boolean turning stateless output either on or off.
Returns the previous value.
"""
old = self.get_stateless_output()
self.nft_ctx_output_set_stateless(self.__ctx, val)
return old
def get_json_output(self):
"""Get the current state of JSON output.
Returns a boolean indicating whether JSON output is active or not.
"""
return self.nft_ctx_output_get_json(self.__ctx)
def set_json_output(self, val):
"""Enable or disable JSON output.
Accepts a boolean turning JSON output either on or off.
Returns the previous value.
"""
old = self.get_json_output()
self.nft_ctx_output_set_json(self.__ctx, val)
return old
def get_debug(self):
"""Get currently active debug flags.
Returns a set of flag names. See set_debug() for details.
"""
val = self.nft_ctx_output_get_debug(self.__ctx)
names = []
for n,v in self.debug_flags.items():
if val & v:
names.append(n)
val &= ~v
if val:
names.append(val)
return names
def set_debug(self, values):
"""Set debug output flags.
Accepts either a single flag or a set of flags. Each flag might be
given either as string or integer value as shown in the following
table:
Name | Value (hex)
-----------------------
scanner | 0x1
parser | 0x2
eval | 0x4
netlink | 0x8
mnl | 0x10
proto-ctx | 0x20
segtree | 0x40
Returns a set of previously active debug flags, as returned by
get_debug() method.
"""
old = self.get_debug()
if type(values) in [str, int]:
values = [values]
val = 0
for v in values:
if type(v) is str:
v = self.debug_flags[v]
val |= v
self.nft_ctx_output_set_debug(self.__ctx, val)
return old
def cmd(self, cmdline):
"""Run a simple nftables command via libnftables.
Accepts a string containing an nftables command just like what one
would enter into an interactive nftables (nft -i) session.
Returns a tuple (rc, output, error):
rc -- return code as returned by nft_run_cmd_from_buffer() fuction
output -- a string containing output written to stdout
error -- a string containing output written to stderr
"""
rc = self.nft_run_cmd_from_buffer(self.__ctx, cmdline)
output = self.nft_ctx_get_output_buffer(self.__ctx)
error = self.nft_ctx_get_error_buffer(self.__ctx)
return (rc, output, error)
def json_cmd(self, json_root):
"""Run an nftables command in JSON syntax via libnftables.
Accepts a hash object as input.
Returns a tuple (rc, output, error):
rc -- reutrn code as returned by nft_run_cmd_from_buffer() function
output -- a hash object containing library standard output
error -- a string containing output written to stderr
"""
json_out_old = self.set_json_output(True)
rc, output, error = self.cmd(json.dumps(json_root))
if not json_out_old:
self.set_json_output(json_out_old)
if len(output):
output = json.loads(output)
return (rc, output, error)
|
