#!/usr/bin/env python
import sys, os, re
import helpers, options, client, server, iptables
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] <subnets...>
sshuttle --iptables <port> <subnets...>
sshuttle --server
--
l,listen=  transproxy to this ip address and port number [default=0]
r,remote=  ssh hostname (and optional username) of remote sshuttle server
v,verbose  increase debug message verbosity
noserver   don't use a separate server process (mostly for debugging)
server     [internal use only]
iptables   [internal use only]
"""
o = options.Options('sshuttle', optspec)
(opt, flags, extra) = o.parse(sys.argv[1:])

helpers.verbose = opt.verbose

try:
    if opt.server:
        sys.exit(server.main())
    elif opt.iptables:
        if len(extra) < 1:
            o.fatal('at least one argument expected')
        sys.exit(iptables.main(int(extra[0]),
                               parse_subnets(extra[1:])))
    else:
        if len(extra) < 1:
            o.fatal('at least one subnet expected')
        remotename = opt.remote
        if remotename == '' or remotename == '-':
            remotename = None
        sys.exit(client.main(parse_ipport(opt.listen or '0.0.0.0:0'),
                             not opt.noserver,
                             remotename,
                             parse_subnets(extra)))
except Fatal, e:
    log('fatal: %s\n' % e)
    sys.exit(99)
except KeyboardInterrupt:
    log('\nKeyboard interrupt: exiting.\n')
    sys.exit(1)