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import struct, socket, select, subprocess, errno
import helpers, ssnet, ssh
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)
class IPTables:
def __init__(self, port, subnets):
self.port = port
self.subnets = subnets
subnets_str = ['%s/%d' % (ip,width) for ip,width in subnets]
argvbase = ([sys.argv[0]] +
['-v'] * (helpers.verbose or 0) +
['--iptables', str(port)] + subnets_str)
argv_tries = [
['sudo'] + argvbase,
['su', '-c', ' '.join(argvbase)],
argvbase
]
# we can't use stdin/stdout=subprocess.PIPE here, as we normally would,
# because stupid Linux 'su' requires that stdin be attached to a tty.
# Instead, attach a *bidirectional* socket to its stdout, and use
# that for talking in both directions.
(s1,s2) = socket.socketpair()
def setup():
# run in the child process
s2.close()
e = None
for argv in argv_tries:
try:
self.p = subprocess.Popen(argv, stdout=s1, preexec_fn=setup)
e = None
break
except OSError, e:
pass
self.argv = argv
s1.close()
self.pfile = s2.makefile('wb+')
if e:
log('Spawning iptables: %r\n' % self.argv)
raise Fatal(e)
line = self.pfile.readline()
self.check()
if line != 'READY\n':
raise Fatal('%r expected READY, got %r' % (self.argv, line))
def check(self):
rv = self.p.poll()
if rv:
raise Fatal('%r returned %d' % (self.argv, rv))
def start(self):
self.pfile.write('GO\n')
self.pfile.flush()
line = self.pfile.readline()
self.check()
if line != 'STARTED\n':
raise Fatal('%r expected STARTED, got %r' % (self.argv, line))
def done(self):
self.pfile.close()
rv = self.p.wait()
if rv:
raise Fatal('cleanup: %r returned %d' % (self.argv, rv))
def _main(listener, ipt, use_server, remotename):
handlers = []
if use_server:
if helpers.verbose >= 1:
helpers.logprefix = 'c : '
else:
helpers.logprefix = 'client: '
(serverproc, serversock) = ssh.connect(remotename)
mux = Mux(serversock, serversock)
handlers.append(mux)
expected = 'SSHUTTLE0001'
initstring = serversock.recv(len(expected))
rv = serverproc.poll()
if rv:
raise Fatal('server died with error code %d' % rv)
if initstring != expected:
raise Fatal('expected server init string %r; got %r'
% (expected, initstring))
# we definitely want to do this *after* starting ssh, or we might end
# up intercepting the ssh connection!
ipt.start()
def onaccept():
sock,srcip = listener.accept()
dstip = original_dst(sock)
debug1('Accept: %r:%r -> %r:%r.\n' % (srcip[0],srcip[1],
dstip[0],dstip[1]))
if dstip == sock.getsockname():
debug1("-- 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 Fatal('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)
debug2('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()
mux.callback()
mux.check_fullness()
def main(listenip, use_server, remotename, subnets):
debug1('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
debug2('Binding:')
for port in ports:
debug2(' %d' % port)
try:
listener.bind((listenip[0], port))
bound = True
break
except socket.error, e:
last_e = e
debug2('\n')
if not bound:
assert(last_e)
raise last_e
listener.listen(10)
listenip = listener.getsockname()
debug1('Listening on %r.\n' % (listenip,))
ipt = IPTables(listenip[1], subnets)
try:
return _main(listener, ipt, use_server, remotename)
finally:
ipt.done()
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