diff options
Diffstat (limited to 'paramiko/transport.py')
| -rw-r--r-- | paramiko/transport.py | 82 |
1 files changed, 68 insertions, 14 deletions
diff --git a/paramiko/transport.py b/paramiko/transport.py index fff11a1d..c43db6e2 100644 --- a/paramiko/transport.py +++ b/paramiko/transport.py @@ -42,7 +42,8 @@ from paramiko.common import xffffffff, cMSG_CHANNEL_OPEN, cMSG_IGNORE, \ MSG_CHANNEL_OPEN_SUCCESS, MSG_CHANNEL_OPEN_FAILURE, MSG_CHANNEL_OPEN, \ MSG_CHANNEL_SUCCESS, MSG_CHANNEL_FAILURE, MSG_CHANNEL_DATA, \ MSG_CHANNEL_EXTENDED_DATA, MSG_CHANNEL_WINDOW_ADJUST, MSG_CHANNEL_REQUEST, \ - MSG_CHANNEL_EOF, MSG_CHANNEL_CLOSE + MSG_CHANNEL_EOF, MSG_CHANNEL_CLOSE, MIN_PACKET_SIZE, MAX_WINDOW_SIZE, \ + DEFAULT_WINDOW_SIZE, DEFAULT_MAX_PACKET_SIZE from paramiko.compress import ZlibCompressor, ZlibDecompressor from paramiko.dsskey import DSSKey from paramiko.kex_gex import KexGex @@ -57,7 +58,7 @@ from paramiko.server import ServerInterface from paramiko.sftp_client import SFTPClient from paramiko.ssh_exception import (SSHException, BadAuthenticationType, ChannelException, ProxyCommandFailure) -from paramiko.util import retry_on_signal +from paramiko.util import retry_on_signal, clamp_value from Crypto.Cipher import Blowfish, AES, DES3, ARC4 try: @@ -135,7 +136,10 @@ class Transport (threading.Thread): _modulus_pack = None - def __init__(self, sock): + def __init__(self, + sock, + default_window_size=DEFAULT_WINDOW_SIZE, + default_max_packet_size=DEFAULT_MAX_PACKET_SIZE): """ Create a new SSH session over an existing socket, or socket-like object. This only creates the `.Transport` object; it doesn't begin the @@ -161,8 +165,19 @@ class Transport (threading.Thread): address and used for communication. Exceptions from the ``socket`` call may be thrown in this case. + .. note:: Modifying the the window and packet sizes might have adverse + effects on your channels created from this transport. The + default values are the same as in the OpenSSH code base and have + been battle tested. + :param socket sock: a socket or socket-like object to create the session over. + :param int default_window_size: + sets the default window size on the transport. (defaults to + 2097152) + :param int default_max_packet_size: + sets the default max packet size on the transport. (defaults to + 32768) """ self.active = False @@ -232,8 +247,8 @@ class Transport (threading.Thread): self.channel_events = {} # (id -> Event) self.channels_seen = {} # (id -> True) self._channel_counter = 1 - self.window_size = 65536 - self.max_packet_size = 34816 + self.default_max_packet_size = default_max_packet_size + self.default_window_size = default_window_size self._forward_agent_handler = None self._x11_handler = None self._tcp_handler = None @@ -528,18 +543,29 @@ class Transport (threading.Thread): """ return self.active - def open_session(self): + def open_session(self, window_size=None, max_packet_size=None): """ Request a new channel to the server, of type ``"session"``. This is just an alias for calling `open_channel` with an argument of ``"session"``. + .. note:: Modifying the the window and packet sizes might have adverse + effects on the session created. The default values are the same + as in the OpenSSH code base and have been battle tested. + + :param int window_size: + optional window size for this session. + :param int max_packet_size: + optional max packet size for this session. + :return: a new `.Channel` :raises SSHException: if the request is rejected or the session ends prematurely """ - return self.open_channel('session') + return self.open_channel('session', + window_size=window_size, + max_packet_size=max_packet_size) def open_x11_channel(self, src_addr=None): """ @@ -581,13 +607,22 @@ class Transport (threading.Thread): """ return self.open_channel('forwarded-tcpip', dest_addr, src_addr) - def open_channel(self, kind, dest_addr=None, src_addr=None): + def open_channel(self, + kind, + dest_addr=None, + src_addr=None, + window_size=None, + max_packet_size=None): """ Request a new channel to the server. `Channels <.Channel>` are socket-like objects used for the actual transfer of data across the session. You may only request a channel after negotiating encryption (using `connect` or `start_client`) and authenticating. + .. note:: Modifying the the window and packet sizes might have adverse + effects on the channel created. The default values are the same + as in the OpenSSH code base and have been battle tested. + :param str kind: the kind of channel requested (usually ``"session"``, ``"forwarded-tcpip"``, ``"direct-tcpip"``, or ``"x11"``) @@ -597,6 +632,11 @@ class Transport (threading.Thread): ``"direct-tcpip"`` (ignored for other channel types) :param src_addr: the source address of this port forwarding, if ``kind`` is ``"forwarded-tcpip"``, ``"direct-tcpip"``, or ``"x11"`` + :param int window_size: + optional window size for this session. + :param int max_packet_size: + optional max packet size for this session. + :return: a new `.Channel` on success :raises SSHException: if the request is rejected or the session ends @@ -606,13 +646,15 @@ class Transport (threading.Thread): raise SSHException('SSH session not active') self.lock.acquire() try: + window_size = self._sanitize_window_size(window_size) + max_packet_size = self._sanitize_packet_size(max_packet_size) chanid = self._next_channel() m = Message() m.add_byte(cMSG_CHANNEL_OPEN) m.add_string(kind) m.add_int(chanid) - m.add_int(self.window_size) - m.add_int(self.max_packet_size) + m.add_int(window_size) + m.add_int(max_packet_size) if (kind == 'forwarded-tcpip') or (kind == 'direct-tcpip'): m.add_string(dest_addr[0]) m.add_int(dest_addr[1]) @@ -626,7 +668,7 @@ class Transport (threading.Thread): self.channel_events[chanid] = event = threading.Event() self.channels_seen[chanid] = True chan._set_transport(self) - chan._set_window(self.window_size, self.max_packet_size) + chan._set_window(window_size, max_packet_size) finally: self.lock.release() self._send_user_message(m) @@ -670,6 +712,7 @@ class Transport (threading.Thread): :param callable handler: optional handler for incoming forwarded connections, of the form ``func(Channel, (str, int), (str, int))``. + :return: the port number (`int`) allocated by the server :raises SSHException: if the server refused the TCP forward request @@ -1391,6 +1434,17 @@ class Transport (threading.Thread): finally: self.lock.release() + def _sanitize_window_size(self, window_size): + if window_size is None: + window_size = self.default_window_size + return clamp_value(MIN_PACKET_SIZE, window_size, MAX_WINDOW_SIZE) + + def _sanitize_packet_size(self, max_packet_size): + if max_packet_size is None: + max_packet_size = self.default_max_packet_size + return clamp_value(MIN_PACKET_SIZE, max_packet_size, MAX_WINDOW_SIZE) + + def run(self): # (use the exposed "run" method, because if we specify a thread target # of a private method, threading.Thread will keep a reference to it @@ -1954,7 +2008,7 @@ class Transport (threading.Thread): self._channels.put(my_chanid, chan) self.channels_seen[my_chanid] = True chan._set_transport(self) - chan._set_window(self.window_size, self.max_packet_size) + chan._set_window(self.default_window_size, self.default_max_packet_size) chan._set_remote_channel(chanid, initial_window_size, max_packet_size) finally: self.lock.release() @@ -1962,8 +2016,8 @@ class Transport (threading.Thread): m.add_byte(cMSG_CHANNEL_OPEN_SUCCESS) m.add_int(chanid) m.add_int(my_chanid) - m.add_int(self.window_size) - m.add_int(self.max_packet_size) + m.add_int(self.default_window_size) + m.add_int(self.default_max_packet_size) self._send_message(m) self._log(DEBUG, 'Secsh channel %d (%s) opened.', my_chanid, kind) if kind == 'auth-agent@openssh.com': |