mirror of
https://github.com/sshuttle/sshuttle.git
synced 2024-11-22 16:03:57 +01:00
Basic implementation of a multiplex protocol - client side only.
Currently the 'server' is just a pipe to run 'hd' (hexdump) for looking at the client-side results. Lame, but true.
This commit is contained in:
Avery Pennarun
parent
9f514d7a15
commit
5f0bfb5d9e
31
client.py
31
client.py
@ -1,13 +1,13 @@
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import struct, socket, select, subprocess, errno
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from ssnet import SockWrapper, Handler, Proxy
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import ssnet, ssh
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from ssnet import SockWrapper, Handler, Proxy, Mux, MuxWrapper
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from helpers import *
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def original_dst(sock):
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SO_ORIGINAL_DST = 80
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SOCKADDR_MIN = 16
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sockaddr_in = sock.getsockopt(socket.SOL_IP, SO_ORIGINAL_DST, SOCKADDR_MIN)
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(proto, port, a,b,c,d) = struct.unpack('!hhBBBB', sockaddr_in[:8])
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(proto, port, a,b,c,d) = struct.unpack('!HHBBBB', sockaddr_in[:8])
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assert(socket.htons(proto) == socket.AF_INET)
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ip = '%d.%d.%d.%d' % (a,b,c,d)
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return (ip,port)
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@ -21,8 +21,17 @@ def iptables_setup(port, subnets):
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raise Exception('%r returned %d' % (argv, rv))
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def _main(listener, remotename, subnets):
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def _main(listener, listenport, use_server, remotename, subnets):
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handlers = []
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if use_server:
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(serverproc, serversock) = ssh.connect(remotename)
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mux = Mux(serversock)
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handlers.append(mux)
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# we definitely want to do this *after* starting ssh, or we might end
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# up intercepting the ssh connection!
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iptables_setup(listenport, subnets)
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def onaccept():
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sock,srcip = listener.accept()
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dstip = original_dst(sock)
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@ -31,10 +40,16 @@ def _main(listener, remotename, subnets):
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log("-- ignored: that's my address!\n")
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sock.close()
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return
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if use_server:
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chan = mux.next_channel()
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mux.send(chan, ssnet.CMD_CONNECT, '%s,%s' % dstip)
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outwrap = MuxWrapper(mux, chan)
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else:
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outsock = socket.socket()
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outsock.setsockopt(socket.SOL_IP, socket.IP_TTL, 42)
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outsock.connect(dstip)
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handlers.append(Proxy(SockWrapper(sock), SockWrapper(outsock)))
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outwrap = SockWrapper(outsock)
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handlers.append(Proxy(SockWrapper(sock), outwrap))
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handlers.append(Handler([listener], onaccept))
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while 1:
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@ -54,7 +69,7 @@ def _main(listener, remotename, subnets):
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s.callback()
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def main(listenip, remotename, subnets):
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def main(listenip, use_server, remotename, subnets):
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log('Starting sshuttle proxy.\n')
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listener = socket.socket()
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listener.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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@ -81,9 +96,7 @@ def main(listenip, remotename, subnets):
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listenip = listener.getsockname()
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log('Listening on %r.\n' % (listenip,))
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iptables_setup(listenip[1], subnets)
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try:
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return _main(listener, remotename, subnets)
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return _main(listener, listenip[1], use_server, remotename, subnets)
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finally:
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iptables_setup(listenip[1], [])
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10
main.py
10
main.py
@ -1,5 +1,5 @@
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#!/usr/bin/env python
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import sys, re
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import sys, os, re
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import options, client, iptables
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@ -50,6 +50,7 @@ sshuttle --server
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--
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l,listen= transproxy to this ip address and port number [default=0]
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r,remote= ssh hostname (and optional username) of remote sshuttle server
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noserver don't use a separate server process (mostly for debugging)
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server [internal use only]
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iptables [internal use only]
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"""
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@ -57,7 +58,9 @@ o = options.Options('sshuttle', optspec)
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(opt, flags, extra) = o.parse(sys.argv[1:])
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if opt.server:
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o.fatal('server mode not implemented yet')
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#o.fatal('server mode not implemented yet')
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os.dup2(2,1)
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os.execvp('hd', ['hd'])
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sys.exit(1)
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elif opt.iptables:
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if len(extra) < 1:
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@ -67,9 +70,10 @@ elif opt.iptables:
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else:
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if len(extra) < 1:
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o.fatal('at least one subnet expected')
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remotename = extra[0]
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remotename = opt.remote
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if remotename == '' or remotename == '-':
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remotename = None
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sys.exit(client.main(parse_ipport(opt.listen or '0.0.0.0:0'),
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not opt.noserver,
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remotename,
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parse_subnets(extra)))
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24
ssh.py
24
ssh.py
@ -1,14 +1,13 @@
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import os, re, subprocess
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import sys, os, re, subprocess, socket
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def connect(rhost, subcmd):
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assert(not re.search(r'[^\w-]', subcmd))
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def connect(rhost):
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main_exe = sys.argv[0]
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nicedir = os.path.split(os.path.abspath(main_exe))[0]
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nicedir = re.sub(r':', "_", nicedir)
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if rhost == '-':
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rhost = None
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if not rhost:
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argv = ['sshuttle', subcmd]
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argv = ['sshuttle', '--server']
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else:
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# WARNING: shell quoting security holes are possible here, so we
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# have to be super careful. We have to use 'sh -c' because
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@ -19,14 +18,21 @@ def connect(rhost, subcmd):
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# stuff here.
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escapedir = re.sub(r'([^\w/])', r'\\\\\\\1', nicedir)
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cmd = r"""
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sh -c PATH=%s:'$PATH sshuttle %s'
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""" % (escapedir, subcmd)
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argv = ['ssh', rhost, '--', cmd.strip()]
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sh -c PATH=%s:'$PATH sshuttle --server'
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""" % (escapedir,)
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argv = ['ssh', '-v', rhost, '--', cmd.strip()]
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print repr(argv)
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(s1,s2) = socket.socketpair()
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def setup():
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# runs in the child process
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s2.close()
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if not rhost:
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os.environ['PATH'] = ':'.join([nicedir,
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os.environ.get('PATH', '')])
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os.setsid()
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return subprocess.Popen(argv, stdin=subprocess.PIPE, stdout=subprocess.PIPE,
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preexec_fn=setup)
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s1a,s1b = os.dup(s1.fileno()), os.dup(s1.fileno())
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s1.close()
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p = subprocess.Popen(argv, stdin=s1a, stdout=s1b, preexec_fn=setup)
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os.close(s1a)
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os.close(s1b)
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return p, s2
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161
ssnet.py
161
ssnet.py
@ -1,6 +1,17 @@
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import socket, errno, select
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import struct, socket, errno, select
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from helpers import *
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HDR_LEN = 8
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CMD_EXIT = 0x4200
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CMD_PING = 0x4201
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CMD_PONG = 0x4202
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CMD_CONNECT = 0x4203
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CMD_CLOSE = 0x4204
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CMD_EOF = 0x4205
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CMD_DATA = 0x4206
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def _nb_clean(func, *args):
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try:
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return func(*args)
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@ -35,28 +46,32 @@ class SockWrapper:
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self.shut_write = True
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self.sock.shutdown(socket.SHUT_WR)
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def write(self, buf):
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assert(buf)
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def uwrite(self, buf):
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self.sock.setblocking(False)
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return _nb_clean(self.sock.send, buf)
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def fill(self):
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def write(self, buf):
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assert(buf)
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return self.uwrite(buf)
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def uread(self):
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if self.shut_read:
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return
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self.sock.setblocking(False)
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rb = _nb_clean(self.sock.recv, 65536)
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return _nb_clean(self.sock.recv, 65536)
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def fill(self):
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if self.buf:
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return
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rb = self.uread()
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if rb:
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self.buf.append(rb)
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if rb == '': # empty string means EOF; None means temporarily empty
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self.noread()
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def maybe_fill(self):
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if not self.buf:
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self.fill()
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def copy_to(self, outwrap):
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if self.buf and self.buf[0]:
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wrote = outwrap.sock.send(self.buf[0])
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wrote = outwrap.write(self.buf[0])
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self.buf[0] = self.buf[0][wrote:]
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while self.buf and not self.buf[0]:
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self.buf.pop(0)
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@ -102,8 +117,8 @@ class Proxy(Handler):
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r.add(self.wrap2.sock)
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def callback(self):
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self.wrap1.maybe_fill()
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self.wrap2.maybe_fill()
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self.wrap1.fill()
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self.wrap2.fill()
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self.wrap1.copy_to(self.wrap2)
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self.wrap2.copy_to(self.wrap1)
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if (self.wrap1.shut_read and self.wrap2.shut_read and
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@ -111,3 +126,125 @@ class Proxy(Handler):
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self.ok = False
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class Mux(Handler):
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def __init__(self, sock):
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Handler.__init__(self, [sock])
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self.sock = sock
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self.channels = {}
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self.chani = 0
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self.want = 0
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self.inbuf = ''
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self.outbuf = []
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self.send(0, CMD_PING, 'chicken')
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def next_channel(self):
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# channel 0 is special, so we never allocate it
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for timeout in xrange(1024):
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self.chani += 1
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if self.chani > 65535:
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self.chani = 1
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if not self.channels.get(self.chani):
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return self.chani
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def send(self, channel, cmd, data):
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data = str(data)
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assert(len(data) <= 65535)
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p = struct.pack('!ccHHH', 'S', 'S', channel, cmd, len(data)) + data
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self.outbuf.append(p)
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log('Mux: send queue is %d/%d\n'
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% (len(self.outbuf), sum(len(b) for b in self.outbuf)))
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def got_packet(self, channel, cmd, data):
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log('--got-packet--\n')
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if cmd == CMD_PING:
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self.mux.send(0, CMD_PONG, data)
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elif cmd == CMD_EXIT:
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self.ok = False
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else:
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c = self.channels[channel]
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c.got_packet(cmd, data)
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def flush(self):
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self.sock.setblocking(False)
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if self.outbuf and self.outbuf[0]:
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wrote = _nb_clean(self.sock.send, self.outbuf[0])
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if wrote:
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self.outbuf[0] = self.outbuf[0][wrote:]
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while self.outbuf and not self.outbuf[0]:
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self.outbuf.pop()
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def fill(self):
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self.sock.setblocking(False)
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b = _nb_clean(self.sock.recv, 32768)
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if b == '': # EOF
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ok = False
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if b:
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self.inbuf += b
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def handle(self):
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log('inbuf is: %r\n' % self.inbuf)
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if len(self.inbuf) >= (self.want or HDR_LEN):
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(s1,s2,channel,cmd,datalen) = struct.unpack('!ccHHH',
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self.inbuf[:HDR_LEN])
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assert(s1 == 'S')
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assert(s2 == 'S')
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self.want = datalen + HDR_LEN
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if self.want and len(self.inbuf) >= self.want:
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data = self.inbuf[HDR_LEN:self.want]
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self.inbuf = self.inbuf[self.want:]
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self.got_packet(channel, cmd, data)
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else:
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self.fill()
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def pre_select(self, r, w, x):
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if self.inbuf < (self.want or HDR_LEN):
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r.add(self.sock)
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if self.outbuf:
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w.add(self.sock)
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def callback(self):
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(r,w,x) = select.select([self.sock], [self.sock], [], 0)
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if self.sock in r:
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self.handle()
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if self.outbuf and self.sock in w:
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self.flush()
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class MuxWrapper(SockWrapper):
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def __init__(self, mux, channel):
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SockWrapper.__init__(self, mux.sock)
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self.mux = mux
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self.channel = channel
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self.mux.channels[channel] = self
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log('Created MuxWrapper on channel %d\n' % channel)
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def noread(self):
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if not self.shut_read:
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self.shut_read = True
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def nowrite(self):
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if not self.shut_write:
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self.shut_write = True
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self.mux.send(self.channel, CMD_EOF, '')
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def uwrite(self, buf):
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self.mux.send(self.channel, CMD_DATA, buf)
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return len(buf)
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def uread(self):
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if self.shut_read:
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return '' # EOF
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else:
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return None # no data available right now
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def got_packet(self, cmd, data):
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if cmd == CMD_CLOSE:
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self.noread()
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self.nowrite()
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elif cmd == CMD_EOF:
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self.noread()
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elif cmd == CMD_DATA:
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self.buf.append(data)
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else:
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raise Exception('unknown command %d (%d bytes)'
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% (cmd, len(data)))
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