sshuttle/main.py

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
dns-domains= comma seperated list of DNS domains for DNS forwarding
dns-to=    forward any DNS requests that don't match domains to this address
python=    path to python interpreter on the remote server
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[2:])

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
        if opt.dns and opt.dns_domains:
            dns_domains = opt.dns_domains.split(",")
            if opt.dns_to:
                addr,colon,port = opt.dns_to.rpartition(":")
                if colon == ":":
                    dns_to = ( addr, int(port) )
                else:
                    dns_to = ( port, 53 )
            else:
                o.fatal('--dns-to=ip is required with --dns-domains=list')
        else:
            dns_domains = None
            dns_to = 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, dns_domains, dns_to,
                             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)