root / ncclient / ssh.py @ 3ad93428
History | View | Annotate | Download (5.1 kB)
1 |
# Copyright 2009 Shikhar Bhushan
|
---|---|
2 |
#
|
3 |
# Licensed under the Apache License, Version 2.0 (the "License");
|
4 |
# you may not use this file except in compliance with the License.
|
5 |
# You may obtain a copy of the License at
|
6 |
#
|
7 |
# http://www.apache.org/licenses/LICENSE-2.0
|
8 |
#
|
9 |
# Unless required by applicable law or agreed to in writing, software
|
10 |
# distributed under the License is distributed on an "AS IS" BASIS,
|
11 |
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
12 |
# See the License for the specific language governing permissions and
|
13 |
# limitations under the License.
|
14 |
|
15 |
import logging |
16 |
import paramiko |
17 |
|
18 |
from os import SEEK_CUR |
19 |
from cStringIO import StringIO |
20 |
|
21 |
from session import Session, SessionError |
22 |
|
23 |
logger = logging.getLogger('ncclient.ssh')
|
24 |
|
25 |
|
26 |
class SessionCloseError(SessionError): |
27 |
|
28 |
def __str__(self): |
29 |
return 'RECEIVED: %s | UNSENT: %s' % (self._in_buf, self._out_buf) |
30 |
|
31 |
def __init__(self, in_buf, out_buf=None): |
32 |
SessionError.__init__(self)
|
33 |
self._in_buf, self._out_buf = in_buf, out_buf |
34 |
|
35 |
|
36 |
class SSHSession(Session): |
37 |
|
38 |
BUF_SIZE = 4096
|
39 |
MSG_DELIM = ']]>]]>'
|
40 |
|
41 |
def __init__(self, load_known_hosts=True, |
42 |
missing_host_key_policy=paramiko.RejectPolicy): |
43 |
Session.__init__(self)
|
44 |
self._client = paramiko.SSHClient()
|
45 |
if load_known_hosts:
|
46 |
self._client.load_system_host_keys()
|
47 |
self._client.set_missing_host_key_policy(missing_host_key_policy)
|
48 |
self._in_buf = StringIO()
|
49 |
self._parsing_state = 0 |
50 |
self._parsing_pos = 0 |
51 |
|
52 |
def load_host_keys(self, filename): |
53 |
self._client.load_host_keys(filename)
|
54 |
|
55 |
def set_missing_host_key_policy(self, policy): |
56 |
self._client.set_missing_host_key_policy(policy)
|
57 |
|
58 |
# paramiko exceptions ok?
|
59 |
# user might be looking for ClientError
|
60 |
def connect(self, hostname, port=830, username=None, password=None, |
61 |
key_filename=None, timeout=None, allow_agent=True, |
62 |
look_for_keys=True):
|
63 |
self._client.connect(hostname, port=port, username=username,
|
64 |
password=password, key_filename=key_filename, |
65 |
timeout=timeout, allow_agent=allow_agent, |
66 |
look_for_keys=look_for_keys) |
67 |
transport = self._client.get_transport()
|
68 |
self._channel = transport.open_session()
|
69 |
self._channel.invoke_subsystem('netconf') |
70 |
self._channel.set_name('netconf') |
71 |
self._connected = True |
72 |
self._post_connect()
|
73 |
|
74 |
def run(self): |
75 |
chan = self._channel
|
76 |
chan.setblocking(0)
|
77 |
q = self._q
|
78 |
try:
|
79 |
while True: |
80 |
if chan.closed:
|
81 |
raise SessionCloseError(self._in_buf.getvalue()) |
82 |
if chan.send_ready() and not q.empty(): |
83 |
data = q.get() + SSHSession.MSG_DELIM |
84 |
while data:
|
85 |
n = chan.send(data) |
86 |
if n <= 0: |
87 |
raise SessionCloseError(self._in_buf.getvalue(), data) |
88 |
data = data[n:] |
89 |
if chan.recv_ready():
|
90 |
data = chan.recv(SSHSession.BUF_SIZE) |
91 |
if data:
|
92 |
self._in_buf.write(data)
|
93 |
self._fresh_data()
|
94 |
else:
|
95 |
raise SessionCloseError(self._in_buf.getvalue()) |
96 |
except Exception as e: |
97 |
logger.debug('*** broke out of main loop ***')
|
98 |
self.dispatch('error', e) |
99 |
|
100 |
def _close(self): |
101 |
self._channel.close()
|
102 |
self._connected = False |
103 |
|
104 |
def _fresh_data(self): |
105 |
delim = SSHSession.MSG_DELIM |
106 |
n = len(delim) - 1 |
107 |
state = self._parsing_state
|
108 |
buf = self._in_buf
|
109 |
buf.seek(self._parsing_pos)
|
110 |
while True: |
111 |
x = buf.read(1)
|
112 |
if not x: # done reading |
113 |
break
|
114 |
elif x == delim[state]:
|
115 |
state += 1
|
116 |
else:
|
117 |
continue
|
118 |
# loop till last delim char expected, break if other char encountered
|
119 |
for i in range(state, n): |
120 |
x = buf.read(1)
|
121 |
if not x: # done reading |
122 |
break
|
123 |
if x==delim[i]: # what we expected |
124 |
state += 1 # expect the next delim char |
125 |
else:
|
126 |
state = 0 # reset |
127 |
break
|
128 |
else: # if we didn't break out of above loop, full delim parsed |
129 |
till = buf.tell() - n |
130 |
buf.seek(0)
|
131 |
msg = buf.read(till) |
132 |
self.dispatch('reply', msg) |
133 |
buf.seek(n+1, SEEK_CUR)
|
134 |
rest = buf.read() |
135 |
buf = StringIO() |
136 |
buf.write(rest) |
137 |
buf.seek(0)
|
138 |
state = 0
|
139 |
self._in_buf = buf
|
140 |
self._parsing_state = state
|
141 |
self._parsing_pos = self._in_buf.tell() |
142 |
|
143 |
class MissingHostKeyPolicy(paramiko.MissingHostKeyPolicy): |
144 |
|
145 |
def __init__(self, cb): |
146 |
self._cb = cb
|
147 |
|
148 |
def missing_host_key(self, client, hostname, key): |
149 |
if not self._cb(hostname, key): |
150 |
raise SSHError
|