sshuttle/main.py
Avery Pennarun a81972b2b5 Add --wrap option to force channel number wrapping at a lower number.
This makes it easier to actually test what happens when channel numbers wrap
around.  The good news: it works.

However, I did find a bug where sshuttle would die if we completely ran out
of available channel numbers because so many of them were open.  This would
never realistically happen at the default of 65535 channels (we'd run out of
file descriptors first), but it's still a bug, so let's handle it by just
dropping the connection when it happens.
2011-02-02 02:32:46 -08:00

132 lines
4.7 KiB
Python
Executable File

#!/usr/bin/env python
import sys, os, re
import helpers, options, client, server, firewall, hostwatch
import compat.ssubprocess as ssubprocess
from helpers import *
# list of:
# 1.2.3.4/5 or just 1.2.3.4
def parse_subnets(subnets_str):
subnets = []
for s in subnets_str:
m = re.match(r'(\d+)(?:\.(\d+)\.(\d+)\.(\d+))?(?:/(\d+))?$', s)
if not m:
raise Fatal('%r is not a valid IP subnet format' % s)
(a,b,c,d,width) = m.groups()
(a,b,c,d) = (int(a or 0), int(b or 0), int(c or 0), int(d or 0))
if width == None:
width = 32
else:
width = int(width)
if a > 255 or b > 255 or c > 255 or d > 255:
raise Fatal('%d.%d.%d.%d has numbers > 255' % (a,b,c,d))
if width > 32:
raise Fatal('*/%d is greater than the maximum of 32' % width)
subnets.append(('%d.%d.%d.%d' % (a,b,c,d), width))
return subnets
# 1.2.3.4:567 or just 1.2.3.4 or just 567
def parse_ipport(s):
s = str(s)
m = re.match(r'(?:(\d+)\.(\d+)\.(\d+)\.(\d+))?(?::)?(?:(\d+))?$', s)
if not m:
raise Fatal('%r is not a valid IP:port format' % s)
(a,b,c,d,port) = m.groups()
(a,b,c,d,port) = (int(a or 0), int(b or 0), int(c or 0), int(d or 0),
int(port or 0))
if a > 255 or b > 255 or c > 255 or d > 255:
raise Fatal('%d.%d.%d.%d has numbers > 255' % (a,b,c,d))
if port > 65535:
raise Fatal('*:%d is greater than the maximum of 65535' % port)
if a == None:
a = b = c = d = 0
return ('%d.%d.%d.%d' % (a,b,c,d), port)
optspec = """
sshuttle [-l [ip:]port] [-r [username@]sshserver[:port]] <subnets...>
sshuttle --server
sshuttle --firewall <port> <subnets...>
sshuttle --hostwatch
--
l,listen= transproxy to this ip address and port number [127.0.0.1:0]
H,auto-hosts scan for remote hostnames and update local /etc/hosts
N,auto-nets automatically determine subnets to route
dns capture local DNS requests and forward to the remote DNS server
python= path to python interpreter on the remote server [python]
r,remote= ssh hostname (and optional username) of remote sshuttle server
x,exclude= exclude this subnet (can be used more than once)
v,verbose increase debug message verbosity
e,ssh-cmd= the command to use to connect to the remote [ssh]
seed-hosts= with -H, use these hostnames for initial scan (comma-separated)
no-latency-control sacrifice latency to improve bandwidth benchmarks
wrap= restart counting channel numbers after this number (for testing)
D,daemon run in the background as a daemon
syslog send log messages to syslog (default if you use --daemon)
pidfile= pidfile name (only if using --daemon) [./sshuttle.pid]
server (internal use only)
firewall (internal use only)
hostwatch (internal use only)
"""
o = options.Options(optspec)
(opt, flags, extra) = o.parse(sys.argv[1:])
if opt.daemon:
opt.syslog = 1
if opt.wrap:
import ssnet
ssnet.MAX_CHANNEL = int(opt.wrap)
helpers.verbose = opt.verbose
try:
if opt.server:
if len(extra) != 0:
o.fatal('no arguments expected')
server.latency_control = opt.latency_control
sys.exit(server.main())
elif opt.firewall:
if len(extra) != 2:
o.fatal('exactly two arguments expected')
sys.exit(firewall.main(int(extra[0]), int(extra[1]), opt.syslog))
elif opt.hostwatch:
sys.exit(hostwatch.hw_main(extra))
else:
if len(extra) < 1 and not opt.auto_nets:
o.fatal('at least one subnet (or -N) expected')
includes = extra
excludes = ['127.0.0.0/8']
for k,v in flags:
if k in ('-x','--exclude'):
excludes.append(v)
remotename = opt.remote
if remotename == '' or remotename == '-':
remotename = None
if opt.seed_hosts and not opt.auto_hosts:
o.fatal('--seed-hosts only works if you also use -H')
if opt.seed_hosts:
sh = re.split(r'[\s,]+', (opt.seed_hosts or "").strip())
elif opt.auto_hosts:
sh = []
else:
sh = None
sys.exit(client.main(parse_ipport(opt.listen or '0.0.0.0:0'),
opt.ssh_cmd,
remotename,
opt.python,
opt.latency_control,
opt.dns,
sh,
opt.auto_nets,
parse_subnets(includes),
parse_subnets(excludes),
opt.syslog, opt.daemon, opt.pidfile))
except Fatal, e:
log('fatal: %s\n' % e)
sys.exit(99)
except KeyboardInterrupt:
log('\n')
log('Keyboard interrupt: exiting.\n')
sys.exit(1)