sshuttle/client.py
Avery Pennarun bfd506dcdc Improve some debugging information to find the weird data problem.
Turns out list.pop() removes the *last* item, not the first one.  Oops.  It
all works great for queues of only one item... :)
2010-05-02 01:25:09 -04:00

117 lines
3.7 KiB
Python

import struct, socket, select, subprocess, errno
import ssnet, ssh, helpers
from ssnet import SockWrapper, Handler, Proxy, Mux, MuxWrapper
from helpers import *
def original_dst(sock):
SO_ORIGINAL_DST = 80
SOCKADDR_MIN = 16
sockaddr_in = sock.getsockopt(socket.SOL_IP, SO_ORIGINAL_DST, SOCKADDR_MIN)
(proto, port, a,b,c,d) = struct.unpack('!HHBBBB', sockaddr_in[:8])
assert(socket.htons(proto) == socket.AF_INET)
ip = '%d.%d.%d.%d' % (a,b,c,d)
return (ip,port)
def iptables_setup(port, subnets):
subnets_str = ['%s/%d' % (ip,width) for ip,width in subnets]
argv = ['sudo', sys.argv[0], '--iptables', str(port)] + subnets_str
rv = subprocess.call(argv)
if rv != 0:
raise Exception('%r returned %d' % (argv, rv))
def _main(listener, listenport, use_server, remotename, subnets):
handlers = []
if use_server:
helpers.logprefix = 'c : '
(serverproc, serversock) = ssh.connect(remotename)
mux = Mux(serversock, serversock)
handlers.append(mux)
expected = 'SSHUTTLE0001'
initstring = serversock.recv(len(expected))
if initstring != expected:
raise Exception('expected server init string %r; got %r'
% (expected, initstring))
rv = serverproc.poll()
if rv:
raise Exception('server died with error code %d' % rv)
# we definitely want to do this *after* starting ssh, or we might end
# up intercepting the ssh connection!
iptables_setup(listenport, subnets)
def onaccept():
sock,srcip = listener.accept()
dstip = original_dst(sock)
log('Accept: %r:%r -> %r:%r.\n' % (srcip[0],srcip[1],
dstip[0],dstip[1]))
if dstip == sock.getsockname():
log("-- ignored: that's my address!\n")
sock.close()
return
if use_server:
chan = mux.next_channel()
mux.send(chan, ssnet.CMD_CONNECT, '%s,%s' % dstip)
outwrap = MuxWrapper(mux, chan)
else:
outwrap = ssnet.connect_dst(dstip[0], dstip[1])
handlers.append(Proxy(SockWrapper(sock, sock), outwrap))
handlers.append(Handler([listener], onaccept))
while 1:
if use_server:
rv = serverproc.poll()
if rv:
raise Exception('server died with error code %d' % rv)
r = set()
w = set()
x = set()
handlers = filter(lambda s: s.ok, handlers)
for s in handlers:
s.pre_select(r,w,x)
log('Waiting: %d[%d,%d,%d]...\n'
% (len(handlers), len(r), len(w), len(x)))
(r,w,x) = select.select(r,w,x)
#log('r=%r w=%r x=%r\n' % (r,w,x))
ready = set(r) | set(w) | set(x)
for s in handlers:
if s.socks & ready:
s.callback()
def main(listenip, use_server, remotename, subnets):
log('Starting sshuttle proxy.\n')
listener = socket.socket()
listener.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
if listenip[1]:
ports = [listenip[1]]
else:
ports = xrange(12300,65536)
last_e = None
bound = False
log('Binding:')
for port in ports:
log(' %d' % port)
try:
listener.bind((listenip[0], port))
bound = True
break
except socket.error, e:
last_e = e
log('\n')
if not bound:
assert(last_e)
raise last_e
listener.listen(10)
listenip = listener.getsockname()
log('Listening on %r.\n' % (listenip,))
try:
return _main(listener, listenip[1], use_server, remotename, subnets)
finally:
iptables_setup(listenip[1], [])