Fix conflicts in localhost detection after removal of ttl code.

Since sshuttle's TTL code was removed in a recent commit, this code
will cause sshuttle to exit when the host specified with -r is
actually the localhost.

.github/dependabot.yml

@@ -0,0 +1,12 @@
+version: 2
+updates:
+- package-ecosystem: pip
+  directory: "/"
+  schedule:
+    interval: daily
+  open-pull-requests-limit: 10
+- package-ecosystem: github-actions
+  directory: "/"
+  schedule:
+    interval: daily
+  open-pull-requests-limit: 10

.github/workflows/pythonpackage.yml

@@ -5,11 +5,11 @@ name: Python package
 
 on:
   push:
-    branches: [ master, tproxy_mark_param ]
+    branches: [ master ]
   pull_request:
-    branches: [ master, tproxy_mark_param ]
+    branches: [ master ]
   workflow_dispatch:
-    branches: [ tproxy_mark_param ]
+    branches: [ master ]
 
 jobs:
   build:
@@ -20,9 +20,9 @@ jobs:
         python-version: [3.6, 3.7, 3.8, 3.9]
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.4
     - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v2
+      uses: actions/setup-python@v2.2.2
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies

README.rst

@@ -46,6 +46,10 @@ Obtaining sshuttle
 
       dnf install sshuttle
       
+ - Gentoo::
+ 
+      emerge -av net-proxy/sshuttle
+
 - NixOS::
 
       nix-env -iA nixos.sshuttle

bin/sudoers-add

@@ -50,6 +50,14 @@ if [ "$FILE_NAME" == "" ]; then
 	exit 1
 fi
 
+# Verify that the resulting file name begins with /etc/sudoers.d
+FILE_NAME="$(realpath "/etc/sudoers.d/$FILE_NAME")"
+if [[ "$FILE_NAME" != "/etc/sudoers.d/"* ]] ; then
+	echo -n "Invalid sudoers filename: Final sudoers file "
+	echo "location ($FILE_NAME) does not begin with /etc/sudoers.d"
+	exit 1
+fi
+
 # Make a temp file to hold the sudoers config
 umask 077
 TEMP_FILE=$(mktemp)
@@ -62,9 +70,9 @@ visudo_code=$?
 rm "$TEMP_FILE"
 
 if [ $visudo_code -eq 0 ]; then
-	echo "$CONTENT" > "/etc/sudoers.d/$FILE_NAME"
+	echo "$CONTENT" > "$FILE_NAME"
-	chmod 0440 "/etc/sudoers.d/$FILE_NAME"
+	chmod 0440 "$FILE_NAME"
-	echo "The sudoers file /etc/sudoers.d/$FILE_NAME has been successfully created!"
+	echo "The sudoers file $FILE_NAME has been successfully created!"
 
 	exit 0
 else

docs/manpage.rst

@@ -4,14 +4,14 @@ sshuttle
 
 Synopsis
 --------
-**sshuttle** [*options*] [**-r** *[username@]sshserver[:port]*] \<*subnets* ...\>
+**sshuttle** [*options*] **-r** *[username@]sshserver[:port]* \<*subnets* ...\>
 
 
 Description
 -----------
 :program:`sshuttle` allows you to create a VPN connection from your
-machine to any remote server that you can connect to via
+machine to any remote server that you can connect to via ssh, as long
-ssh, as long as that server has python 3.6 or higher.
+as that server has a sufficiently new Python installation.
 
 To work, you must have root access on the local machine,
 but you can have a normal account on the server.
@@ -32,21 +32,22 @@ Options
 
     A list of subnets to route over the VPN, in the form
     ``a.b.c.d[/width][port[-port]]``. Valid examples are 1.2.3.4 (a
-    single IP address), 1.2.3.4/32 (equivalent to 1.2.3.4),
+    single IP address) and 1.2.3.4/32 (equivalent to 1.2.3.4),
-    1.2.3.0/24 (a 24-bit subnet, ie. with a 255.255.255.0
+    1.2.3.0/24 (a 24-bit subnet, ie. with a 255.255.255.0 netmask).
-    netmask), and 0/0 ('just route everything through the
+    Specify subnets 0/0 to match all IPv4 addresses and ::/0 to match
-    VPN'). Any of the previous examples are also valid if you append
+    all IPv6 addresses. Any of the previous examples are also valid if
-    a port or a port range, so 1.2.3.4:8000 will only tunnel traffic
+    you append a port or a port range, so 1.2.3.4:8000 will only
-    that has as the destination port 8000 of 1.2.3.4 and
+    tunnel traffic that has as the destination port 8000 of 1.2.3.4
-    1.2.3.0/24:8000-9000 will tunnel traffic going to any port between
+    and 1.2.3.0/24:8000-9000 will tunnel traffic going to any port
-    8000 and 9000 (inclusive) for all IPs in the 1.2.3.0/24 subnet.
+    between 8000 and 9000 (inclusive) for all IPs in the 1.2.3.0/24
-    A hostname can be provided instead of an IP address. If the
+    subnet. A hostname can be provided instead of an IP address. If
-    hostname resolves to multiple IPs, all of the IPs are included.
+    the hostname resolves to multiple IPs, all of the IPs are
-    If a width is provided with a hostname that the width is applied
+    included. If a width is provided with a hostname, the width is
-    to all of the hostnames IPs (if they are all either IPv4 or IPv6).
+    applied to all of the hostnames IPs (if they are all either IPv4
-    Widths cannot be supplied to hostnames that resolve to both IPv4
+    or IPv6). Widths cannot be supplied to hostnames that resolve to
-    and IPv6. Valid examples are example.com, example.com:8000,
+    both IPv4 and IPv6. Valid examples are example.com,
-    example.com/24, example.com/24:8000 and example.com:8000-9000.
+    example.com:8000, example.com/24, example.com/24:8000 and
+    example.com:8000-9000.
 
 .. option:: --method <auto|nat|nft|tproxy|pf|ipfw>
 
@@ -88,6 +89,13 @@ Options
     few subnets over the VPN, you probably would prefer to
     keep using your local DNS server for everything else.
 
+    :program:`sshuttle` tries to store a cache of the hostnames in
+    ~/.sshuttle.hosts on the remote host. Similarly, it tries to read
+    the file when you later reconnect to the host with --auto-hosts
+    enabled to quickly populate the host list. When troubleshooting
+    this feature, try removing this file on the remote host when
+    sshuttle is not running.
+
 .. option:: -N, --auto-nets
 
     In addition to the subnets provided on the command
@@ -141,7 +149,10 @@ Options
     The remote hostname and optional username and ssh
     port number to use for connecting to the remote server.
     For example, example.com, testuser@example.com,
-    testuser@example.com:2222, or example.com:2244.
+    testuser@example.com:2222, or example.com:2244. This
+    hostname is passed to ssh, so it will recognize any
+    aliases and settings you may have configured in
+    ~/.ssh/config.
 
 .. option:: -x <subnet>, --exclude=<subnet>
 
@@ -174,7 +185,7 @@ Options
 
     A comma-separated list of hostnames to use to
     initialize the :option:`--auto-hosts` scan algorithm.
-    :option:`--auto-hosts` does things like poll local SMB servers
+    :option:`--auto-hosts` does things like poll netstat output
     for lists of local hostnames, but can speed things up
     if you use this option to give it a few names to start
     from.
@@ -274,9 +285,10 @@ Options
     Set the file name for the sudoers.d file to be added. Default is
     "sshuttle_auto". Only works with --sudoers.
 
-.. option:: -t, --tmark
+.. option:: -t <mark>, --tmark=<mark>
 
-    Transproxy optional traffic mark with provided MARK value.
+    An option used by the tproxy method: Use the specified traffic
+    mark. The mark must be a hexadecimal value. Defaults to 0x01.
 
 .. option:: --version
 
@@ -305,11 +317,8 @@ Arguments read from a file must be one per line, as shown below::
     --option2
     value2
 
-Comments in config file
+The configuration file supports comments for human-readable
-.......................
+annotations. For example::
-
-It's possible to add comments in the configuration file. This allows annotating the
-various subnets with human-readable descriptions, like::
 
     # company-internal API
     8.8.8.8/32
@@ -319,51 +328,96 @@ various subnets with human-readable descriptions, like::
 
 Examples
 --------
-Test locally by proxying all local connections, without using ssh::
 
-    $ sshuttle -v 0/0
+Use the following command to route all IPv4 TCP traffic through remote
+(-r) host example.com (and possibly other traffic too, depending on
+the selected --method). The 0/0 subnet, short for 0.0.0.0/0, matches
+all IPv4 addresses. The ::/0 subnet, matching all IPv6 addresses could
+be added to the example. We also exclude (-x) example.com:22 so that
+we can establish ssh connections from our local machine to the remote
+host without them being routed through sshuttle. Excluding the remote
+host may be necessary on some machines for sshuttle to work properly.
+Press Ctrl+C to exit. To also route DNS queries through sshuttle, try
+adding --dns. Add or remove -v options to see more or less
+information::
 
-    Starting sshuttle proxy.
+    $ sshuttle -r example.com -x example.com:22 0/0
-    Listening on ('0.0.0.0', 12300).
+
+    Starting sshuttle proxy (version ...).
     [local sudo] Password: 
-    firewall manager ready.
+    fw: Starting firewall with Python version 3.9.5
-    c : connecting to server...
+    fw: ready method name nat.
-     s: available routes:
+    c : IPv6 disabled since it isn't supported by method nat.
-     s:   192.168.42.0/24
+    c : Method: nat
-    c : connected.
+    c : IPv4: on
-    firewall manager: starting transproxy.
+    c : IPv6: off (not available with nat method)
-    c : Accept: 192.168.42.106:50035 -> 192.168.42.121:139.
+    c : UDP : off (not available with nat method)
-    c : Accept: 192.168.42.121:47523 -> 77.141.99.22:443.
+    c : DNS : off (available)
-        ...etc...
+    c : User: off (available)
+    c : Subnets to forward through remote host (type, IP, cidr mask width, startPort, endPort):
+    c :   (<AddressFamily.AF_INET: 2>, '0.0.0.0', 0, 0, 0)
+    c : Subnets to exclude from forwarding:
+    c :   (<AddressFamily.AF_INET: 2>, '...', 32, 22, 22)
+    c :   (<AddressFamily.AF_INET: 2>, '127.0.0.1', 32, 0, 0)
+    c : TCP redirector listening on ('127.0.0.1', 12299).
+    c : Starting client with Python version 3.9.5
+    c : Connecting to server...
+    user@example.com's password: 
+     s: Starting server with Python version 3.6.8
+     s: latency control setting = True
+     s: auto-nets:False
+    c : Connected to server.
+    fw: setting up.
+    fw: iptables -w -t nat -N sshuttle-12299
+    fw: iptables -w -t nat -F sshuttle-12299
+    ...
+    Accept: 192.168.42.121:60554 -> 77.141.99.22:22.
     ^C
-    firewall manager: undoing changes.
-    KeyboardInterrupt
     c : Keyboard interrupt: exiting.
-    c : SW#8:192.168.42.121:47523: deleting
+    c : SW'unknown':Mux#1: deleting (1 remain)
-    c : SW#6:192.168.42.106:50035: deleting
+    c : SW#7:192.168.42.121:60554: deleting (0 remain)
 
-Test connection to a remote server, with automatic hostname
+
+Connect to a remote server, with automatic hostname
 and subnet guessing::
 
-    $ sshuttle -vNHr example.org
+    $ sshuttle -vNHr example.com -x example.com:22
-
+    Starting sshuttle proxy (version ...).
-    Starting sshuttle proxy.
+    [local sudo] Password: 
-    Listening on ('0.0.0.0', 12300).
+    fw: Starting firewall with Python version 3.9.5
-    firewall manager ready.
+    fw: ready method name nat.
-    c : connecting to server...
+    c : IPv6 disabled since it isn't supported by method nat.
+    c : Method: nat
+    c : IPv4: on
+    c : IPv6: off (not available with nat method)
+    c : UDP : off (not available with nat method)
+    c : DNS : off (available)
+    c : User: off (available)
+    c : Subnets to forward through remote host (type, IP, cidr mask width, startPort, endPort):
+    c : NOTE: Additional subnets to forward may be added below by --auto-nets.
+    c : Subnets to exclude from forwarding:
+    c :   (<AddressFamily.AF_INET: 2>, '...', 32, 22, 22)
+    c :   (<AddressFamily.AF_INET: 2>, '127.0.0.1', 32, 0, 0)
+    c : TCP redirector listening on ('127.0.0.1', 12300).
+    c : Starting client with Python version 3.9.5
+    c : Connecting to server...
+    user@example.com's password: 
+     s: Starting server with Python version 3.6.8
+     s: latency control setting = True
+     s: auto-nets:True
+    c : Connected to server.
+    c : seed_hosts: []
      s: available routes:
      s:   77.141.99.0/24
-    c : connected.
+    fw: setting up.
-    c : seed_hosts: []
+    fw: iptables -w -t nat -N sshuttle-12300
-    firewall manager: starting transproxy.
+    fw: iptables -w -t nat -F sshuttle-12300
-    hostwatch: Found: testbox1: 1.2.3.4
+    ...
-    hostwatch: Found: mytest2: 5.6.7.8
-    hostwatch: Found: domaincontroller: 99.1.2.3
     c : Accept: 192.168.42.121:60554 -> 77.141.99.22:22.
     ^C
-    firewall manager: undoing changes.
     c : Keyboard interrupt: exiting.
-    c : SW#6:192.168.42.121:60554: deleting
+    c : SW'unknown':Mux#1: deleting (1 remain)
+    c : SW#7:192.168.42.121:60554: deleting (0 remain)
 
 Run :program:`sshuttle` with a `/etc/sshuttle.conf` configuration file::
 
@@ -387,9 +441,7 @@ Example configuration file::
 Discussion
 ----------
 When it starts, :program:`sshuttle` creates an ssh session to the
-server specified by the ``-r`` option.  If ``-r`` is omitted,
+server specified by the ``-r`` option.
-it will start both its client and server locally, which is
-sometimes useful for testing.
 
 After connecting to the remote server, :program:`sshuttle` uploads its
 (python) source code to the remote end and executes it

docs/requirements.rst

@@ -15,10 +15,12 @@ Supports:
 
 * IPv4 TCP
 * IPv4 DNS
+* IPv6 TCP
+* IPv6 DNS
 
 Requires:
 
-* iptables DNAT, REDIRECT, and ttl modules.
+* iptables DNAT and REDIRECT modules. ip6tables for IPv6.
 
 Linux with nft method
 ~~~~~~~~~~~~~~~~~~~~~

docs/tproxy.rst

@@ -12,7 +12,8 @@ There are some things you need to consider for TPROXY to work:
       ip -6 route add local default dev lo table 100
       ip -6 rule add fwmark {TMARK} lookup 100
   
-  where {TMARK} is the identifier mark passed with -t or --tmark flag (default value is 1).
+  where {TMARK} is the identifier mark passed with -t or --tmark flag
+  as a hexadecimal string (default value is '0x01').
 
 - The ``--auto-nets`` feature does not detect IPv6 routes automatically. Add IPv6
   routes manually. e.g. by adding ``'::/0'`` to the end of the command line.

docs/usage.rst

@@ -11,6 +11,10 @@ Forward all traffic::
     sshuttle -r username@sshserver 0.0.0.0/0
 
 - Use the :option:`sshuttle -r` parameter to specify a remote server.
+  One some systems, you may also need to use the :option:`sshuttle -x`
+  parameter to exclude sshserver or sshserver:22 so that your local
+  machine can communicate directly to sshserver without it being
+  redirected by sshuttle.
 
 - By default sshuttle will automatically choose a method to use. Override with
   the :option:`sshuttle --method` parameter.

requirements-tests.txt

@@ -1,5 +1,5 @@
 -r requirements.txt
-pytest==6.2.2
+pytest==6.2.4
-pytest-cov==2.11.1
+pytest-cov==2.12.1
-flake8==3.8.4
+flake8==3.9.2
-pyflakes==2.2.0
+pyflakes==2.3.1

requirements.txt

@@ -1,2 +1 @@
-setuptools-scm==5.0.2
+setuptools-scm==6.0.1
-psutil

setup.py

@@ -63,7 +63,6 @@ setup(
     },
     python_requires='>=3.6',
     install_requires=[
-        'psutil',
     ],
     tests_require=[
         'pytest',

sshuttle/assembler.py

@@ -42,4 +42,4 @@ import sshuttle.cmdline_options as options  # noqa: E402
 from sshuttle.server import main  # noqa: E402
 main(options.latency_control, options.latency_buffer_size,
      options.auto_hosts, options.to_nameserver,
-     options.auto_nets, options.ttl, options.localhost_detector)
+     options.auto_nets, options.localhost_detector)

sshuttle/client.py

@@ -7,7 +7,6 @@ import os
 import sys
 import platform
 import tempfile
-import psutil
 
 import sshuttle.helpers as helpers
 import sshuttle.ssnet as ssnet
@@ -46,6 +45,7 @@ def got_signal(signum, frame):
     sys.exit(1)
 
 
+# Filename of the pidfile created by the sshuttle client.
 _pidname = None
 
 # This variable is set to true if the client and the server appear to
@@ -204,14 +204,13 @@ class MultiListener:
 
 class FirewallClient:
 
-    def __init__(self, method_name, sudo_pythonpath, ttl):
+    def __init__(self, method_name, sudo_pythonpath):
         self.auto_nets = []
-        python_path = os.path.dirname(os.path.dirname(__file__))
+
         argvbase = ([sys.executable, sys.argv[0]] +
                     ['-v'] * (helpers.verbose or 0) +
                     ['--method', method_name] +
-                    ['--firewall'] +
+                    ['--firewall'])
-                    ['--ttl', ttl])
         if ssyslog._p:
             argvbase += ['--syslog']
 
@@ -229,7 +228,8 @@ class FirewallClient:
 
         if sudo_pythonpath:
             elev_prefix += ['/usr/bin/env',
-                            'PYTHONPATH=%s' % python_path]
+                            'PYTHONPATH=%s' %
+                            os.path.dirname(os.path.dirname(__file__))]
         argv_tries = [elev_prefix + argvbase, argvbase]
 
         # we can't use stdin/stdout=subprocess.PIPE here, as we normally would,
@@ -266,7 +266,7 @@ class FirewallClient:
 
     def setup(self, subnets_include, subnets_exclude, nslist,
               redirectport_v6, redirectport_v4, dnsport_v6, dnsport_v4, udp,
-              user, tmark, ttl):
+              user, tmark):
         self.subnets_include = subnets_include
         self.subnets_exclude = subnets_exclude
         self.nslist = nslist
@@ -277,7 +277,6 @@ class FirewallClient:
         self.udp = udp
         self.user = user
         self.tmark = tmark
-        self.ttl = ttl
 
     def check(self):
         rv = self.p.poll()
@@ -316,7 +315,8 @@ class FirewallClient:
         else:
             user = b'%d' % self.user
 
-        self.pfile.write(b'GO %d %s\n' % (udp, user))
+        self.pfile.write(b'GO %d %s %s\n' %
+                         (udp, user, bytes(self.tmark, 'ascii')))
         self.pfile.flush()
 
         line = self.pfile.readline()
@@ -461,7 +461,7 @@ def ondns(listener, method, mux, handlers):
 def _main(tcp_listener, udp_listener, fw, ssh_cmd, remotename,
           python, latency_control, latency_buffer_size,
           dns_listener, seed_hosts, auto_hosts, auto_nets, daemon,
-          to_nameserver, ttl):
+          to_nameserver):
 
     helpers.logprefix = 'c : '
     debug1('Starting client with Python version %s'
@@ -491,7 +491,6 @@ def _main(tcp_listener, udp_listener, fw, ssh_cmd, remotename,
                          auto_hosts=auto_hosts,
                          to_nameserver=to_nameserver,
                          auto_nets=auto_nets,
-                         ttl=ttl,
                          localhost_detector=localhost_detector))
     except socket.error as e:
         if e.args[0] == errno.EPIPE:
@@ -676,7 +675,9 @@ def _main(tcp_listener, udp_listener, fw, ssh_cmd, remotename,
             # poll() won't tell us when process exited since the
             # process is no longer our child (it returns 0 all the
             # time).
-            if not psutil.pid_exists(serverproc.pid):
+            try:
+                os.kill(serverproc.pid, 0)
+            except OSError:
                 raise Fatal('ssh connection to server (pid %d) exited.' %
                             serverproc.pid)
         else:
@@ -698,12 +699,11 @@ def main(listenip_v6, listenip_v4,
          latency_buffer_size, dns, nslist,
          method_name, seed_hosts, auto_hosts, auto_nets,
          subnets_include, subnets_exclude, daemon, to_nameserver, pidfile,
-         user, sudo_pythonpath, tmark, ttl):
+         user, sudo_pythonpath, tmark):
 
     if not remotename:
-        print("WARNING: You must specify -r/--remote to securely route "
+        raise Fatal("You must use -r/--remote to specify a remote "
-              "traffic to a remote machine. Running without -r/--remote "
+                    "host to route traffic through.")
-              "is only recommended for testing.")
 
     if daemon:
         try:
@@ -714,21 +714,28 @@ def main(listenip_v6, listenip_v4,
     debug1('Starting sshuttle proxy (version %s).' % __version__)
     helpers.logprefix = 'c : '
 
-    fw = FirewallClient(method_name, sudo_pythonpath, ttl)
+    fw = FirewallClient(method_name, sudo_pythonpath)
 
-    # If --dns is used, store the IP addresses that the client
+    # nslist is the list of name severs to intercept. If --dns is
-    # normally uses for DNS lookups in nslist. The firewall needs to
+    # used, we add all DNS servers in resolv.conf. Otherwise, the list
-    # redirect packets outgoing to this server to the remote host
+    # can be populated with the --ns-hosts option (which is already
+    # stored in nslist). This list is used to setup the firewall so it
+    # can redirect packets outgoing to this server to the remote host
     # instead.
     if dns:
         nslist += resolvconf_nameservers(True)
+
+    # If we are intercepting DNS requests, we tell the remote host
+    # where it should send the DNS requests to with the --to-ns
+    # option.
+    if len(nslist) > 0:
         if to_nameserver is not None:
             to_nameserver = "%s@%s" % tuple(to_nameserver[1:])
-    else:
+    else:  # if we are not intercepting DNS traffic
-        # option doesn't make sense if we aren't proxying dns
+        # ...and the user specified a server to send DNS traffic to.
         if to_nameserver and len(to_nameserver) > 0:
-            print("WARNING: --to-ns option is ignored because --dns was not "
+            print("WARNING: --to-ns option is ignored unless "
-                  "used.")
+                  "--dns or --ns-hosts is used.")
         to_nameserver = None
 
     # Get family specific subnet lists. Also, the user may not specify
@@ -1024,14 +1031,14 @@ def main(listenip_v6, listenip_v4,
     # start the firewall
     fw.setup(subnets_include, subnets_exclude, nslist,
              redirectport_v6, redirectport_v4, dnsport_v6, dnsport_v4,
-             required.udp, user, tmark, ttl)
+             required.udp, user, tmark)
 
     # start the client process
     try:
         return _main(tcp_listener, udp_listener, fw, ssh_cmd, remotename,
                      python, latency_control, latency_buffer_size,
                      dns_listener, seed_hosts, auto_hosts, auto_nets,
-                     daemon, to_nameserver, ttl)
+                     daemon, to_nameserver)
     finally:
         try:
             if daemon:

sshuttle/cmdline.py

@@ -20,7 +20,7 @@ def main():
             return 1
 
         if not opt.sudoers_filename:
-            log('--sudoers-file must be set or omited.')
+            log('--sudoers-file must be set or omitted.')
             return 1
 
         sudoers(
@@ -43,7 +43,7 @@ def main():
         if opt.firewall:
             if opt.subnets or opt.subnets_file:
                 parser.error('exactly zero arguments expected')
-            return firewall.main(opt.method, opt.syslog, opt.ttl)
+            return firewall.main(opt.method, opt.syslog)
         elif opt.hostwatch:
             return hostwatch.hw_main(opt.subnets, opt.auto_hosts)
         else:
@@ -85,6 +85,13 @@ def main():
                 ipport_v4 = "auto"
                 # parse_ipport6('[::1]:0')
                 ipport_v6 = "auto" if not opt.disable_ipv6 else None
+            try:
+                int(opt.tmark, 16)
+            except ValueError:
+                parser.error("--tmark must be a hexadecimal value")
+            opt.tmark = opt.tmark.lower()   # make 'x' in 0x lowercase
+            if not opt.tmark.startswith("0x"):  # accept without 0x prefix
+                opt.tmark = "0x%s" % opt.tmark
             if opt.syslog:
                 ssyslog.start_syslog()
                 ssyslog.close_stdin()
@@ -109,8 +116,7 @@ def main():
                                       opt.pidfile,
                                       opt.user,
                                       opt.sudo_pythonpath,
-                                      opt.tmark,
+                                      opt.tmark)
-                                      opt.ttl)
 
             if return_code == 0:
                 log('Normal exit code, exiting...')

sshuttle/firewall.py

@@ -5,6 +5,7 @@ import sys
 import os
 import platform
 import traceback
+import subprocess as ssubprocess
 
 import sshuttle.ssyslog as ssyslog
 import sshuttle.helpers as helpers
@@ -89,6 +90,29 @@ def subnet_weight(s):
     return (-s[-1] + (s[-2] or -65535), s[1], s[2])
 
 
+def flush_systemd_dns_cache():
+    # If the user is using systemd-resolve for DNS resolution, it is
+    # possible for the request to go through systemd-resolve before we
+    # see it...and it may use a cached result instead of sending a
+    # request that we can intercept. When sshuttle starts and stops,
+    # this means that we should clear the cache!
+    #
+    # The command to do this was named systemd-resolve, but changed to
+    # resolvectl in systemd 239.
+    # https://github.com/systemd/systemd/blob/f8eb41003df1a4eab59ff9bec67b2787c9368dbd/NEWS#L3816
+
+    if helpers.which("resolvectl"):
+        debug2("Flushing systemd's DNS resolver cache: "
+               "resolvectl flush-caches")
+        ssubprocess.Popen(["resolvectl", "flush-caches"],
+                          stdout=ssubprocess.PIPE, env=helpers.get_env())
+    elif helpers.which("systemd-resolve"):
+        debug2("Flushing systemd's DNS resolver cache: "
+               "systemd-resolve --flush-caches")
+        ssubprocess.Popen(["systemd-resolve", "--flush-caches"],
+                          stdout=ssubprocess.PIPE, env=helpers.get_env())
+
+
 # This is some voodoo for setting up the kernel's transparent
 # proxying stuff.  If subnets is empty, we just delete our sshuttle rules;
 # otherwise we delete it, then make them from scratch.
@@ -97,7 +121,7 @@ def subnet_weight(s):
 # exit.  In case that fails, it's not the end of the world; future runs will
 # supercede it in the transproxy list, at least, so the leftover rules
 # are hopefully harmless.
-def main(method_name, syslog, ttl):
+def main(method_name, syslog):
     helpers.logprefix = 'fw: '
     stdin, stdout = setup_daemon()
     hostmap = {}
@@ -199,11 +223,12 @@ def main(method_name, syslog, ttl):
         raise Fatal('expected GO but got %r' % line)
 
     _, _, args = line.partition(" ")
-    udp, user = args.strip().split(" ", 1)
+    udp, user, tmark = args.strip().split(" ", 2)
     udp = bool(int(udp))
     if user == '-':
         user = None
-    debug2('Got udp: %r, user: %r' % (udp, user))
+    debug2('Got udp: %r, user: %r, tmark: %s' %
+           (udp, user, tmark))
 
     subnets_v6 = [i for i in subnets if i[0] == socket.AF_INET6]
     nslist_v6 = [i for i in nslist if i[0] == socket.AF_INET6]
@@ -218,15 +243,16 @@ def main(method_name, syslog, ttl):
             method.setup_firewall(
                 port_v6, dnsport_v6, nslist_v6,
                 socket.AF_INET6, subnets_v6, udp,
-                user, ttl)
+                user, tmark)
 
         if subnets_v4 or nslist_v4:
             debug2('setting up IPv4.')
             method.setup_firewall(
                 port_v4, dnsport_v4, nslist_v4,
                 socket.AF_INET, subnets_v4, udp,
-                user, ttl)
+                user, tmark)
 
+        flush_systemd_dns_cache()
         stdout.write('STARTED\n')
 
         try:
@@ -288,3 +314,12 @@ def main(method_name, syslog, ttl):
                 debug1(traceback.format_exc())
             except BaseException:
                 debug2('An error occurred, ignoring it.')
+
+        try:
+            flush_systemd_dns_cache()
+        except BaseException:
+            try:
+                debug1("Error trying to flush systemd dns cache.")
+                debug1(traceback.format_exc())
+            except BaseException:
+                debug2("An error occurred, ignoring it.")

sshuttle/hostwatch.py

@@ -15,9 +15,9 @@ POLL_TIME = 60 * 15
 NETSTAT_POLL_TIME = 30
 CACHEFILE = os.path.expanduser('~/.sshuttle.hosts')
 
+# Have we already failed to write CACHEFILE?
+CACHE_WRITE_FAILED = False
 
-_nmb_ok = True
-_smb_ok = True
 hostnames = {}
 queue = {}
 try:
@@ -33,7 +33,10 @@ def _is_ip(s):
 
 
 def write_host_cache():
+    """If possible, write our hosts file to disk so future connections
+       can reuse the hosts that we already found."""
     tmpname = '%s.%d.tmp' % (CACHEFILE, os.getpid())
+    global CACHE_WRITE_FAILED
     try:
         f = open(tmpname, 'wb')
         for name, ip in sorted(hostnames.items()):
@@ -41,7 +44,15 @@ def write_host_cache():
         f.close()
         os.chmod(tmpname, 384)  # 600 in octal, 'rw-------'
         os.rename(tmpname, CACHEFILE)
-    finally:
+        CACHE_WRITE_FAILED = False
+    except (OSError, IOError):
+        # Write message if we haven't yet or if we get a failure after
+        # a previous success.
+        if not CACHE_WRITE_FAILED:
+            log("Failed to write host cache to temporary file "
+                "%s and rename it to %s" % (tmpname, CACHEFILE))
+            CACHE_WRITE_FAILED = True
+
         try:
             os.unlink(tmpname)
         except BaseException:
@@ -49,25 +60,34 @@ def write_host_cache():
 
 
 def read_host_cache():
+    """If possible, read the cache file from disk to populate hosts that
+       were found in a previous sshuttle run."""
     try:
         f = open(CACHEFILE)
-    except IOError:
+    except (OSError, IOError):
         _, e = sys.exc_info()[:2]
         if e.errno == errno.ENOENT:
             return
         else:
-            raise
+            log("Failed to read existing host cache file %s on remote host"
+                % CACHEFILE)
+            return
     for line in f:
         words = line.strip().split(',')
         if len(words) == 2:
             (name, ip) = words
             name = re.sub(r'[^-\w\.]', '-', name).strip()
+            # Remove characters that shouldn't be in IP
             ip = re.sub(r'[^0-9.]', '', ip).strip()
             if name and ip:
                 found_host(name, ip)
 
 
 def found_host(name, ip):
+    """The provided name maps to the given IP. Add the host to the
+       hostnames list, send the host to the sshuttle client via
+       stdout, and write the host to the cache file.
+    """
     hostname = re.sub(r'\..*', '', name)
     hostname = re.sub(r'[^-\w\.]', '_', hostname)
     if (ip.startswith('127.') or ip.startswith('255.') or
@@ -86,29 +106,37 @@ def found_host(name, ip):
 
 
 def _check_etc_hosts():
-    debug2(' > hosts')
+    """If possible, read /etc/hosts to find hosts."""
-    for line in open('/etc/hosts'):
+    filename = '/etc/hosts'
-        line = re.sub(r'#.*', '', line)
+    debug2(' > Reading %s on remote host' % filename)
+    try:
+        for line in open(filename):
+            line = re.sub(r'#.*', '', line)  # remove comments
             words = line.strip().split()
             if not words:
                 continue
             ip = words[0]
-        names = words[1:]
             if _is_ip(ip):
+                names = words[1:]
                 debug3('<    %s %r' % (ip, names))
                 for n in names:
                     check_host(n)
                     found_host(n, ip)
+    except (OSError, IOError):
+        debug1("Failed to read %s on remote host" % filename)
 
 
 def _check_revdns(ip):
+    """Use reverse DNS to try to get hostnames from an IP addresses."""
     debug2(' > rev: %s' % ip)
     try:
         r = socket.gethostbyaddr(ip)
         debug3('<    %s' % r[0])
         check_host(r[0])
         found_host(r[0], ip)
-    except (socket.herror, UnicodeError):
+    except (OSError, socket.error, UnicodeError):
+        # This case is expected to occur regularly.
+        # debug3('<    %s gethostbyaddr failed on remote host' % ip)
         pass
 
 
@@ -136,115 +164,23 @@ def _check_netstat():
         log('%r failed: %r' % (argv, e))
         return
 
+    # The same IPs may appear multiple times. Consolidate them so the
+    # debug message doesn't print the same IP repeatedly.
+    ip_list = []
     for ip in re.findall(r'\d+\.\d+\.\d+\.\d+', content):
+        if ip not in ip_list:
+            ip_list.append(ip)
+
+    for ip in sorted(ip_list):
         debug3('<    %s' % ip)
         check_host(ip)
 
 
-def _check_smb(hostname):
-    return
-    global _smb_ok
-    if not _smb_ok:
-        return
-    debug2(' > smb: %s' % hostname)
-    argv = ['smbclient', '-U', '%', '-L', hostname]
-    try:
-        p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE, stderr=null,
-                              env=get_env())
-        lines = p.stdout.readlines()
-        p.wait()
-    except OSError:
-        _, e = sys.exc_info()[:2]
-        log('%r failed: %r' % (argv, e))
-        _smb_ok = False
-        return
-
-    lines.reverse()
-
-    # junk at top
-    while lines:
-        line = lines.pop().strip()
-        if re.match(r'Server\s+', line):
-            break
-
-    # server list section:
-    #    Server   Comment
-    #    ------   -------
-    while lines:
-        line = lines.pop().strip()
-        if not line or re.match(r'-+\s+-+', line):
-            continue
-        if re.match(r'Workgroup\s+Master', line):
-            break
-        words = line.split()
-        hostname = words[0].lower()
-        debug3('<    %s' % hostname)
-        check_host(hostname)
-
-    # workgroup list section:
-    #   Workgroup  Master
-    #   ---------  ------
-    while lines:
-        line = lines.pop().strip()
-        if re.match(r'-+\s+', line):
-            continue
-        if not line:
-            break
-        words = line.split()
-        (workgroup, hostname) = (words[0].lower(), words[1].lower())
-        debug3('<    group(%s) -> %s' % (workgroup, hostname))
-        check_host(hostname)
-        check_workgroup(workgroup)
-
-    if lines:
-        assert(0)
-
-
-def _check_nmb(hostname, is_workgroup, is_master):
-    return
-    global _nmb_ok
-    if not _nmb_ok:
-        return
-    debug2(' > n%d%d: %s' % (is_workgroup, is_master, hostname))
-    argv = ['nmblookup'] + ['-M'] * is_master + ['--', hostname]
-    try:
-        p = ssubprocess.Popen(argv, stdout=ssubprocess.PIPE, stderr=null,
-                              env=get_env)
-        lines = p.stdout.readlines()
-        rv = p.wait()
-    except OSError:
-        _, e = sys.exc_info()[:2]
-        log('%r failed: %r' % (argv, e))
-        _nmb_ok = False
-        return
-    if rv:
-        log('%r returned %d' % (argv, rv))
-        return
-    for line in lines:
-        m = re.match(r'(\d+\.\d+\.\d+\.\d+) (\w+)<\w\w>\n', line)
-        if m:
-            g = m.groups()
-            (ip, name) = (g[0], g[1].lower())
-            debug3('<    %s -> %s' % (name, ip))
-            if is_workgroup:
-                _enqueue(_check_smb, ip)
-            else:
-                found_host(name, ip)
-                check_host(name)
-
-
 def check_host(hostname):
     if _is_ip(hostname):
         _enqueue(_check_revdns, hostname)
     else:
         _enqueue(_check_dns, hostname)
-    _enqueue(_check_smb, hostname)
-    _enqueue(_check_nmb, hostname, False, False)
-
-
-def check_workgroup(hostname):
-    _enqueue(_check_nmb, hostname, True, False)
-    _enqueue(_check_nmb, hostname, True, True)
 
 
 def _enqueue(op, *args):
@@ -277,18 +213,22 @@ def hw_main(seed_hosts, auto_hosts):
         _enqueue(_check_netstat)
         check_host('localhost')
         check_host(socket.gethostname())
-        check_workgroup('workgroup')
-        check_workgroup('-')
 
     while 1:
         now = time.time()
+        # For each item in the queue
         for t, last_polled in list(queue.items()):
             (op, args) = t
             if not _stdin_still_ok(0):
                 break
+
+            # Determine if we need to run.
             maxtime = POLL_TIME
+            # netstat runs more often than other jobs
             if op == _check_netstat:
                 maxtime = NETSTAT_POLL_TIME
+
+            # Check if this jobs needs to run.
             if now - last_polled > maxtime:
                 queue[t] = time.time()
                 op(*args)
@@ -298,5 +238,5 @@ def hw_main(seed_hosts, auto_hosts):
                 break
 
         # FIXME: use a smarter timeout based on oldest last_polled
-        if not _stdin_still_ok(1):
+        if not _stdin_still_ok(1):  # sleeps for up to 1 second
             break

sshuttle/linux.py

@@ -17,7 +17,7 @@ def ipt_chain_exists(family, table, name):
         cmd = 'iptables'
     else:
         raise Exception('Unsupported family "%s"' % family_to_string(family))
-    argv = [cmd, '-t', table, '-nL']
+    argv = [cmd, '-w', '-t', table, '-nL']
     try:
         output = ssubprocess.check_output(argv, env=get_env())
         for line in output.decode('ASCII').split('\n'):
@@ -29,9 +29,9 @@ def ipt_chain_exists(family, table, name):
 
 def ipt(family, table, *args):
     if family == socket.AF_INET6:
-        argv = ['ip6tables', '-t', table] + list(args)
+        argv = ['ip6tables', '-w', '-t', table] + list(args)
     elif family == socket.AF_INET:
-        argv = ['iptables', '-t', table] + list(args)
+        argv = ['iptables', '-w', '-t', table] + list(args)
     else:
         raise Exception('Unsupported family "%s"' % family_to_string(family))
     debug1('%s' % ' '.join(argv))
@@ -49,25 +49,3 @@ def nft(family, table, action, *args):
     rv = ssubprocess.call(argv, env=get_env())
     if rv:
         raise Fatal('%r returned %d' % (argv, rv))
-
-
-_no_ttl_module = False
-
-
-def ipt_ttl(family, *args):
-    global _no_ttl_module
-    if not _no_ttl_module:
-        # we avoid infinite loops by generating server-side connections
-        # with ttl 63.  This makes the client side not recapture those
-        # connections, in case client == server.
-        try:
-            argsplus = list(args)
-            ipt(family, *argsplus)
-        except Fatal:
-            ipt(family, *args)
-            # we only get here if the non-ttl attempt succeeds
-            log('WARNING: your iptables is missing '
-                'the ttl module.')
-            _no_ttl_module = True
-    else:
-        ipt(family, *args)

sshuttle/methods/__init__.py

@@ -91,7 +91,7 @@ class BaseMethod(object):
                     (key, self.name))
 
     def setup_firewall(self, port, dnsport, nslist, family, subnets, udp,
-                       user):
+                       user, tmark):
         raise NotImplementedError()
 
     def restore_firewall(self, port, family, udp, user):

sshuttle/methods/ipfw.py

@@ -177,7 +177,6 @@ class Method(BaseMethod):
         sender.setsockopt(socket.SOL_IP, IP_BINDANY, 1)
         sender.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
         sender.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
-        sender.setsockopt(socket.SOL_IP, socket.IP_TTL, 63)
         sender.bind(srcip)
         sender.sendto(data, dstip)
         sender.close()
@@ -189,7 +188,12 @@ class Method(BaseMethod):
         #     udp_listener.v6.setsockopt(SOL_IPV6, IPV6_RECVDSTADDR, 1)
 
     def setup_firewall(self, port, dnsport, nslist, family, subnets, udp,
-                       user, ttl):
+                       user, tmark):
+        # TODO: The ttl hack to allow the host and server to run on
+        # the same machine has been removed but this method hasn't
+        # been updated yet.
+        ttl = 63
+
         # IPv6 not supported
         if family not in [socket.AF_INET]:
             raise Exception(

sshuttle/methods/nat.py

@@ -1,7 +1,7 @@
 import socket
 from sshuttle.firewall import subnet_weight
 from sshuttle.helpers import family_to_string, which, debug2
-from sshuttle.linux import ipt, ipt_ttl, ipt_chain_exists, nonfatal
+from sshuttle.linux import ipt, ipt_chain_exists, nonfatal
 from sshuttle.methods import BaseMethod
 
 
@@ -13,23 +13,18 @@ class Method(BaseMethod):
     # recently-started one will win (because we use "-I OUTPUT 1" instead of
     # "-A OUTPUT").
     def setup_firewall(self, port, dnsport, nslist, family, subnets, udp,
-                       user, ttl):
+                       user, tmark):
-        # only ipv4 supported with NAT
+        if family != socket.AF_INET and family != socket.AF_INET6:
-        if family != socket.AF_INET:
             raise Exception(
                 'Address family "%s" unsupported by nat method_name'
                 % family_to_string(family))
         if udp:
             raise Exception("UDP not supported by nat method_name")
-
         table = "nat"
 
         def _ipt(*args):
             return ipt(family, table, *args)
 
-        def _ipt_ttl(*args):
-            return ipt_ttl(family, table, *args)
-
         def _ipm(*args):
             return ipt(family, "mangle", *args)
 
@@ -50,16 +45,11 @@ class Method(BaseMethod):
         _ipt('-I', 'OUTPUT', '1', *args)
         _ipt('-I', 'PREROUTING', '1', *args)
 
-        # This TTL hack allows the client and server to run on the
-        # same host. The connections the sshuttle server makes will
-        # have TTL set to 63.
-        _ipt_ttl('-A', chain, '-j', 'RETURN', '-m', 'ttl', '--ttl', '%s' % ttl)
-
         # Redirect DNS traffic as requested. This includes routing traffic
         # to localhost DNS servers through sshuttle.
         for _, ip in [i for i in nslist if i[0] == family]:
             _ipt('-A', chain, '-j', 'REDIRECT',
-                 '--dest', '%s/32' % ip,
+                 '--dest', '%s' % ip,
                  '-p', 'udp',
                  '--dport', '53',
                  '--to-ports', str(dnsport))
@@ -87,7 +77,7 @@ class Method(BaseMethod):
 
     def restore_firewall(self, port, family, udp, user):
         # only ipv4 supported with NAT
-        if family != socket.AF_INET:
+        if family != socket.AF_INET and family != socket.AF_INET6:
             raise Exception(
                 'Address family "%s" unsupported by nat method_name'
                 % family_to_string(family))
@@ -99,9 +89,6 @@ class Method(BaseMethod):
         def _ipt(*args):
             return ipt(family, table, *args)
 
-        def _ipt_ttl(*args):
-            return ipt_ttl(family, table, *args)
-
         def _ipm(*args):
             return ipt(family, "mangle", *args)
 
@@ -123,6 +110,7 @@ class Method(BaseMethod):
     def get_supported_features(self):
         result = super(Method, self).get_supported_features()
         result.user = True
+        result.ipv6 = True
         return result
 
     def is_supported(self):

sshuttle/methods/nft.py

@@ -13,7 +13,7 @@ class Method(BaseMethod):
     # recently-started one will win (because we use "-I OUTPUT 1" instead of
     # "-A OUTPUT").
     def setup_firewall(self, port, dnsport, nslist, family, subnets, udp,
-                       user, ttl):
+                       user, tmark):
         if udp:
             raise Exception("UDP not supported by nft")
 
@@ -45,14 +45,6 @@ class Method(BaseMethod):
         else:
             _nft('add rule', chain, 'meta', 'nfproto', '!=', 'ipv6', 'return')
 
-        # This TTL hack allows the client and server to run on the
-        # same host. The connections the sshuttle server makes will
-        # have TTL set to 63.
-        if family == socket.AF_INET:
-            _nft('add rule', chain, 'ip ttl == 63 return')
-        elif family == socket.AF_INET6:
-            _nft('add rule', chain, 'ip6 hoplimit == 63 return')
-
         # Strings to use below to simplify our code
         if family == socket.AF_INET:
             ip_version_l = 'ipv4'

sshuttle/methods/pf.py

@@ -11,8 +11,8 @@ from fcntl import ioctl
 from ctypes import c_char, c_uint8, c_uint16, c_uint32, Union, Structure, \
     sizeof, addressof, memmove
 from sshuttle.firewall import subnet_weight
-from sshuttle.helpers import debug1, debug2, debug3, Fatal, family_to_string, \
+from sshuttle.helpers import log, debug1, debug2, debug3, Fatal, \
-    get_env, which
+     family_to_string, get_env, which
 from sshuttle.methods import BaseMethod
 
 
@@ -393,6 +393,10 @@ def pfctl(args, stdin=None):
                           env=get_env())
     o = p.communicate(stdin)
     if p.returncode:
+        log('%r returned %d, stdout and stderr follows: ' %
+            (argv, p.returncode))
+        log("stdout:\n%s" % o[0].decode("ascii"))
+        log("stderr:\n%s" % o[1].decode("ascii"))
         raise Fatal('%r returned %d' % (argv, p.returncode))
 
     return o
@@ -444,7 +448,7 @@ class Method(BaseMethod):
         return sock.getsockname()
 
     def setup_firewall(self, port, dnsport, nslist, family, subnets, udp,
-                       user, ttl):
+                       user, tmark):
         if family not in [socket.AF_INET, socket.AF_INET6]:
             raise Exception(
                 'Address family "%s" unsupported by pf method_name'

sshuttle/methods/tproxy.py

@@ -1,7 +1,7 @@
 import struct
 from sshuttle.firewall import subnet_weight
 from sshuttle.helpers import family_to_string
-from sshuttle.linux import ipt, ipt_ttl, ipt_chain_exists
+from sshuttle.linux import ipt, ipt_chain_exists
 from sshuttle.methods import BaseMethod
 from sshuttle.helpers import debug1, debug2, debug3, Fatal, which
 
@@ -151,17 +151,7 @@ class Method(BaseMethod):
             udp_listener.v6.setsockopt(SOL_IPV6, IPV6_RECVORIGDSTADDR, 1)
 
     def setup_firewall(self, port, dnsport, nslist, family, subnets, udp,
-                       user, ttl):
+                       user, tmark):
-        if self.firewall is None:
-            tmark = '1'
-        else:
-            tmark = self.firewall.tmark
-
-        self.setup_firewall_tproxy(port, dnsport, nslist, family, subnets, udp,
-                                   user, tmark)
-
-    def setup_firewall_tproxy(self, port, dnsport, nslist, family, subnets,
-                              udp, user, tmark):
         if family not in [socket.AF_INET, socket.AF_INET6]:
             raise Exception(
                 'Address family "%s" unsupported by tproxy method'
@@ -172,9 +162,6 @@ class Method(BaseMethod):
         def _ipt(*args):
             return ipt(family, table, *args)
 
-        def _ipt_ttl(*args):
-            return ipt_ttl(family, table, *args)
-
         def _ipt_proto_ports(proto, fport, lport):
             return proto + ('--dport', '%d:%d' % (fport, lport)) \
                     if fport else proto
@@ -192,8 +179,8 @@ class Method(BaseMethod):
         _ipt('-F', divert_chain)
         _ipt('-N', tproxy_chain)
         _ipt('-F', tproxy_chain)
-        _ipt('-I', 'OUTPUT', tmark, '-j', mark_chain)
+        _ipt('-I', 'OUTPUT', '1', '-j', mark_chain)
-        _ipt('-I', 'PREROUTING', tmark, '-j', tproxy_chain)
+        _ipt('-I', 'PREROUTING', '1', '-j', tproxy_chain)
 
         # Don't have packets sent to any of our local IP addresses go
         # through the tproxy or mark chains.
@@ -224,7 +211,7 @@ class Method(BaseMethod):
                  '--dest', '%s/32' % ip,
                  '-m', 'udp', '-p', 'udp', '--dport', '53')
             _ipt('-A', tproxy_chain, '-j', 'TPROXY',
-                 '--tproxy-mark', '0x'+tmark+'/0x'+tmark,
+                 '--tproxy-mark', tmark,
                  '--dest', '%s/32' % ip,
                  '-m', 'udp', '-p', 'udp', '--dport', '53',
                  '--on-port', str(dnsport))
@@ -249,7 +236,7 @@ class Method(BaseMethod):
                      '-m', 'tcp',
                      *tcp_ports)
                 _ipt('-A', tproxy_chain, '-j', 'TPROXY',
-                     '--tproxy-mark', '0x'+tmark+'/0x'+tmark,
+                     '--tproxy-mark', tmark,
                      '--dest', '%s/%s' % (snet, swidth),
                      '-m', 'tcp',
                      *(tcp_ports + ('--on-port', str(port))))
@@ -273,7 +260,7 @@ class Method(BaseMethod):
                          '-m', 'udp',
                          *udp_ports)
                     _ipt('-A', tproxy_chain, '-j', 'TPROXY',
-                         '--tproxy-mark', '0x'+tmark+'/0x'+tmark,
+                         '--tproxy-mark', tmark,
                          '--dest', '%s/%s' % (snet, swidth),
                          '-m', 'udp',
                          *(udp_ports + ('--on-port', str(port))))
@@ -289,9 +276,6 @@ class Method(BaseMethod):
         def _ipt(*args):
             return ipt(family, table, *args)
 
-        def _ipt_ttl(*args):
-            return ipt_ttl(family, table, *args)
-
         mark_chain = 'sshuttle-m-%s' % port
         tproxy_chain = 'sshuttle-t-%s' % port
         divert_chain = 'sshuttle-d-%s' % port

sshuttle/options.py

@@ -132,6 +132,7 @@ def parse_ipport(s):
 
 
 def parse_list(lst):
+    """Parse a comma separated string into a list."""
     return re.split(r'[\s,]+', lst.strip()) if lst else []
 
 
@@ -172,7 +173,7 @@ class MyArgumentParser(ArgumentParser):
 
 parser = MyArgumentParser(
     prog="sshuttle",
-    usage="%(prog)s [-l [ip:]port] [-r [user@]sshserver[:port]] <subnets...>",
+    usage="%(prog)s [-l [ip:]port] -r [user@]sshserver[:port] <subnets...>",
     fromfile_prefix_chars="@"
 )
 parser.add_argument(
@@ -220,6 +221,7 @@ parser.add_argument(
     type=parse_list,
     help="""
     capture and forward DNS requests made to the following servers
+    (comma separated)
     """
 )
 parser.add_argument(
@@ -280,7 +282,7 @@ parser.add_argument(
     action="count",
     default=0,
     help="""
-    increase debug message verbosity
+    increase debug message verbosity (can be used more than once)
     """
 )
 parser.add_argument(
@@ -387,14 +389,6 @@ parser.add_argument(
     (internal use only)
     """
 )
-parser.add_argument(
-    "--ttl",
-    default="63",
-    help="""
-    Override the TTL for the connections made by the sshuttle server.
-    Default is 63.
-    """
-)
 parser.add_argument(
     "--hostwatch",
     action="store_true",
@@ -444,8 +438,9 @@ parser.add_argument(
 parser.add_argument(
     "-t", "--tmark",
     metavar="[MARK]",
-    default="1",
+    default="0x01",
     help="""
-    transproxy optional traffic mark with provided MARK value
+    tproxy optional traffic mark with provided MARK value in
+    hexadecimal (default '0x01')
     """
 )

sshuttle/server.py

@@ -154,7 +154,7 @@ class Hostwatch:
 
 class DnsProxy(Handler):
 
-    def __init__(self, mux, chan, request, to_nameserver, ttl):
+    def __init__(self, mux, chan, request, to_nameserver):
         Handler.__init__(self, [])
         self.timeout = time.time() + 30
         self.mux = mux
@@ -164,7 +164,6 @@ class DnsProxy(Handler):
         self.peers = {}
         self.to_ns_peer = None
         self.to_ns_port = None
-        self.ttl = ttl
         if to_nameserver is None:
             self.to_nameserver = None
         else:
@@ -194,7 +193,6 @@ class DnsProxy(Handler):
 
         family, sockaddr = self._addrinfo(peer, port)
         sock = socket.socket(family, socket.SOCK_DGRAM)
-        sock.setsockopt(socket.SOL_IP, socket.IP_TTL, self.ttl)
         sock.connect(sockaddr)
 
         self.peers[sock] = peer
@@ -243,15 +241,13 @@ class DnsProxy(Handler):
 
 class UdpProxy(Handler):
 
-    def __init__(self, mux, chan, family, ttl):
+    def __init__(self, mux, chan, family):
         sock = socket.socket(family, socket.SOCK_DGRAM)
         Handler.__init__(self, [sock])
         self.timeout = time.time() + 30
         self.mux = mux
         self.chan = chan
         self.sock = sock
-        if family == socket.AF_INET:
-            self.sock.setsockopt(socket.SOL_IP, socket.IP_TTL, ttl)
 
     def send(self, dstip, data):
         debug2('UDP: sending to %r port %d' % dstip)
@@ -275,7 +271,7 @@ class UdpProxy(Handler):
 
 
 def main(latency_control, latency_buffer_size, auto_hosts, to_nameserver,
-         auto_nets, ttl, localhost_detector):
+         auto_nets, localhost_detector):
     try:
         helpers.logprefix = ' s: '
         debug1('Starting server with Python version %s'
@@ -362,7 +358,7 @@ def main(latency_control, latency_buffer_size, auto_hosts, to_nameserver,
 
         def dns_req(channel, data):
             debug2('Incoming DNS request channel=%d.' % channel)
-            h = DnsProxy(mux, channel, data, to_nameserver, ttl)
+            h = DnsProxy(mux, channel, data, to_nameserver)
             handlers.append(h)
             dnshandlers[channel] = h
         mux.got_dns_req = dns_req
@@ -393,7 +389,7 @@ def main(latency_control, latency_buffer_size, auto_hosts, to_nameserver,
                 raise Fatal('UDP connection channel %d already open' %
                             channel)
             else:
-                h = UdpProxy(mux, channel, family, ttl)
+                h = UdpProxy(mux, channel, family)
                 handlers.append(h)
                 udphandlers[channel] = h
         mux.got_udp_open = udp_open

sshuttle/ssnet.py

@@ -586,7 +586,7 @@ class MuxWrapper(SockWrapper):
 def connect_dst(family, ip, port):
     debug2('Connecting to %s:%d' % (ip, port))
     outsock = socket.socket(family)
-    outsock.setsockopt(socket.SOL_IP, socket.IP_TTL, 63)
+
     return SockWrapper(outsock, outsock,
                        connect_to=(ip, port),
                        peername='%s:%d' % (ip, port))

sshuttle/sudoers.py

@@ -19,9 +19,14 @@ Cmnd_Alias %(ca)s = /usr/bin/env PYTHONPATH=%(dist_packages)s %(py)s %(path)s *
 %(user_name)s ALL=NOPASSWD: %(ca)s
 '''
 
+warning_msg = "# WARNING: When you allow a user to run sshuttle as root,\n" \
+              "# they can then use sshuttle's --ssh-cmd option to run any\n" \
+              "# command as root.\n"
+
 
 def build_config(user_name):
-    content = template % {
+    content = warning_msg
+    content += template % {
         'ca': command_alias,
         'dist_packages': path_to_dist_packages,
         'py': sys.executable,
@@ -42,6 +47,7 @@ def save_config(content, file_name):
     process.stdin.write(content.encode())
 
     streamdata = process.communicate()[0]
+    sys.stdout.write(streamdata.decode("ASCII"))
     returncode = process.returncode
 
     if returncode:
@@ -61,4 +67,5 @@ def sudoers(user_name=None, no_modify=None, file_name=None):
         sys.stdout.write(content)
         exit(0)
     else:
+        sys.stdout.write(warning_msg)
         save_config(content, file_name)

tests/client/test_firewall.py

@@ -15,7 +15,7 @@ NSLIST
 {inet},1.2.3.33
 {inet6},2404:6800:4004:80c::33
 PORTS 1024,1025,1026,1027
-GO 1 -
+GO 1 - 0x01
 HOST 1.2.3.3,existing
 """.format(inet=AF_INET, inet6=AF_INET6))
     stdout = Mock()
@@ -100,7 +100,7 @@ def test_main(mock_get_method, mock_setup_daemon, mock_rewrite_etc_hosts):
     mock_get_method("not_auto").name = "test"
     mock_get_method.reset_mock()
 
-    sshuttle.firewall.main("not_auto", False, 63)
+    sshuttle.firewall.main("not_auto", False)
 
     assert mock_rewrite_etc_hosts.mock_calls == [
         call({'1.2.3.3': 'existing'}, 1024),
@@ -126,7 +126,7 @@ def test_main(mock_get_method, mock_setup_daemon, mock_rewrite_etc_hosts):
                 (AF_INET6, 128, True, u'2404:6800:4004:80c::101f', 80, 80)],
             True,
             None,
-            63),
+            '0x01'),
         call().setup_firewall(
             1025, 1027,
             [(AF_INET, u'1.2.3.33')],
@@ -135,7 +135,7 @@ def test_main(mock_get_method, mock_setup_daemon, mock_rewrite_etc_hosts):
                 (AF_INET, 32, True, u'1.2.3.66', 8080, 8080)],
             True,
             None,
-            63),
+            '0x01'),
         call().restore_firewall(1024, AF_INET6, True, None),
         call().restore_firewall(1025, AF_INET, True, None),
     ]

tests/client/test_methods_nat.py

@@ -11,7 +11,7 @@ from sshuttle.methods import get_method
 def test_get_supported_features():
     method = get_method('nat')
     features = method.get_supported_features()
-    assert not features.ipv6
+    assert features.ipv6
     assert not features.udp
     assert features.dns
 
@@ -85,27 +85,52 @@ def test_firewall_command():
 
 
 @patch('sshuttle.methods.nat.ipt')
-@patch('sshuttle.methods.nat.ipt_ttl')
 @patch('sshuttle.methods.nat.ipt_chain_exists')
-def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
+def test_setup_firewall(mock_ipt_chain_exists, mock_ipt):
     mock_ipt_chain_exists.return_value = True
     method = get_method('nat')
     assert method.name == 'nat'
 
-    with pytest.raises(Exception) as excinfo:
+    assert mock_ipt_chain_exists.mock_calls == []
+    assert mock_ipt.mock_calls == []
     method.setup_firewall(
         1024, 1026,
         [(AF_INET6, u'2404:6800:4004:80c::33')],
         AF_INET6,
         [(AF_INET6, 64, False, u'2404:6800:4004:80c::', 0, 0),
          (AF_INET6, 128, True, u'2404:6800:4004:80c::101f', 80, 80)],
-            True,
+        False,
         None,
-            63)
+        '0x01')
-    assert str(excinfo.value) \
+
-        == 'Address family "AF_INET6" unsupported by nat method_name'
+    assert mock_ipt_chain_exists.mock_calls == [
+        call(AF_INET6, 'nat', 'sshuttle-1024')
+    ]
+    assert mock_ipt.mock_calls == [
+        call(AF_INET6, 'nat', '-D', 'OUTPUT', '-j', 'sshuttle-1024'),
+        call(AF_INET6, 'nat', '-D', 'PREROUTING', '-j', 'sshuttle-1024'),
+        call(AF_INET6, 'nat', '-F', 'sshuttle-1024'),
+        call(AF_INET6, 'nat', '-X', 'sshuttle-1024'),
+        call(AF_INET6, 'nat', '-N', 'sshuttle-1024'),
+        call(AF_INET6, 'nat', '-F', 'sshuttle-1024'),
+        call(AF_INET6, 'nat', '-I', 'OUTPUT', '1', '-j', 'sshuttle-1024'),
+        call(AF_INET6, 'nat', '-I', 'PREROUTING', '1', '-j', 'sshuttle-1024'),
+        call(AF_INET6, 'nat', '-A', 'sshuttle-1024', '-j', 'REDIRECT',
+             '--dest', u'2404:6800:4004:80c::33', '-p', 'udp',
+             '--dport', '53', '--to-ports', '1026'),
+        call(AF_INET6, 'nat', '-A', 'sshuttle-1024', '-j', 'RETURN',
+             '-m', 'addrtype', '--dst-type', 'LOCAL'),
+        call(AF_INET6, 'nat', '-A', 'sshuttle-1024', '-j', 'RETURN',
+             '--dest', u'2404:6800:4004:80c::101f/128', '-p', 'tcp',
+             '--dport', '80:80'),
+        call(AF_INET6, 'nat', '-A', 'sshuttle-1024', '-j', 'REDIRECT',
+             '--dest', u'2404:6800:4004:80c::/64', '-p', 'tcp',
+             '--to-ports', '1024')
+    ]
+    mock_ipt_chain_exists.reset_mock()
+    mock_ipt.reset_mock()
+
     assert mock_ipt_chain_exists.mock_calls == []
-    assert mock_ipt_ttl.mock_calls == []
     assert mock_ipt.mock_calls == []
 
     with pytest.raises(Exception) as excinfo:
@@ -117,10 +142,9 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
                 (AF_INET, 32, True, u'1.2.3.66', 8080, 8080)],
             True,
             None,
-            63)
+            '0x01')
     assert str(excinfo.value) == 'UDP not supported by nat method_name'
     assert mock_ipt_chain_exists.mock_calls == []
-    assert mock_ipt_ttl.mock_calls == []
     assert mock_ipt.mock_calls == []
 
     method.setup_firewall(
@@ -131,14 +155,10 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
             (AF_INET, 32, True, u'1.2.3.66', 8080, 8080)],
         False,
         None,
-        63)
+        '0x01')
     assert mock_ipt_chain_exists.mock_calls == [
         call(AF_INET, 'nat', 'sshuttle-1025')
     ]
-    assert mock_ipt_ttl.mock_calls == [
-        call(AF_INET, 'nat', '-A', 'sshuttle-1025', '-j', 'RETURN',
-             '-m', 'ttl', '--ttl', '63')
-    ]
     assert mock_ipt.mock_calls == [
         call(AF_INET, 'nat', '-D', 'OUTPUT', '-j', 'sshuttle-1025'),
         call(AF_INET, 'nat', '-D', 'PREROUTING', '-j', 'sshuttle-1025'),
@@ -149,7 +169,7 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
         call(AF_INET, 'nat', '-I', 'OUTPUT', '1', '-j', 'sshuttle-1025'),
         call(AF_INET, 'nat', '-I', 'PREROUTING', '1', '-j', 'sshuttle-1025'),
         call(AF_INET, 'nat', '-A', 'sshuttle-1025', '-j', 'REDIRECT',
-             '--dest', u'1.2.3.33/32', '-p', 'udp',
+             '--dest', u'1.2.3.33', '-p', 'udp',
              '--dport', '53', '--to-ports', '1027'),
         call(AF_INET, 'nat', '-A', 'sshuttle-1025', '-j', 'RETURN',
              '-m', 'addrtype', '--dst-type', 'LOCAL'),
@@ -160,20 +180,33 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
              '--to-ports', '1025')
     ]
     mock_ipt_chain_exists.reset_mock()
-    mock_ipt_ttl.reset_mock()
     mock_ipt.reset_mock()
 
     method.restore_firewall(1025, AF_INET, False, None)
     assert mock_ipt_chain_exists.mock_calls == [
         call(AF_INET, 'nat', 'sshuttle-1025')
     ]
-    assert mock_ipt_ttl.mock_calls == []
     assert mock_ipt.mock_calls == [
-        call(AF_INET, 'nat', '-D', 'OUTPUT', '-j', 'sshuttle-1025'),
+        call(AF_INET, 'nat', '-D', 'OUTPUT', '-j',
-        call(AF_INET, 'nat', '-D', 'PREROUTING', '-j', 'sshuttle-1025'),
+             'sshuttle-1025'),
+        call(AF_INET, 'nat', '-D', 'PREROUTING', '-j',
+             'sshuttle-1025'),
         call(AF_INET, 'nat', '-F', 'sshuttle-1025'),
         call(AF_INET, 'nat', '-X', 'sshuttle-1025')
     ]
     mock_ipt_chain_exists.reset_mock()
-    mock_ipt_ttl.reset_mock()
+    mock_ipt.reset_mock()
+
+    method.restore_firewall(1025, AF_INET6, False, None)
+    assert mock_ipt_chain_exists.mock_calls == [
+        call(AF_INET6, 'nat', 'sshuttle-1025')
+    ]
+    assert mock_ipt.mock_calls == [
+        call(AF_INET6, 'nat', '-D', 'OUTPUT', '-j', 'sshuttle-1025'),
+        call(AF_INET6, 'nat', '-D', 'PREROUTING', '-j',
+             'sshuttle-1025'),
+        call(AF_INET6, 'nat', '-F', 'sshuttle-1025'),
+        call(AF_INET6, 'nat', '-X', 'sshuttle-1025')
+    ]
+    mock_ipt_chain_exists.reset_mock()
     mock_ipt.reset_mock()

tests/client/test_methods_pf.py

@@ -187,7 +187,7 @@ def test_setup_firewall_darwin(mock_pf_get_dev, mock_ioctl, mock_pfctl):
             (AF_INET6, 128, True, u'2404:6800:4004:80c::101f', 8080, 8080)],
         False,
         None,
-        63)
+        '0x01')
     assert mock_ioctl.mock_calls == [
         call(mock_pf_get_dev(), 0xC4704433, ANY),
         call(mock_pf_get_dev(), 0xCC20441A, ANY),
@@ -227,7 +227,7 @@ def test_setup_firewall_darwin(mock_pf_get_dev, mock_ioctl, mock_pfctl):
                 (AF_INET, 32, True, u'1.2.3.66', 80, 80)],
             True,
             None,
-            63)
+            '0x01')
     assert str(excinfo.value) == 'UDP not supported by pf method_name'
     assert mock_pf_get_dev.mock_calls == []
     assert mock_ioctl.mock_calls == []
@@ -241,7 +241,7 @@ def test_setup_firewall_darwin(mock_pf_get_dev, mock_ioctl, mock_pfctl):
             (AF_INET, 32, True, u'1.2.3.66', 80, 80)],
         False,
         None,
-        63)
+        '0x01')
     assert mock_ioctl.mock_calls == [
         call(mock_pf_get_dev(), 0xC4704433, ANY),
         call(mock_pf_get_dev(), 0xCC20441A, ANY),
@@ -302,7 +302,7 @@ def test_setup_firewall_freebsd(mock_pf_get_dev, mock_ioctl, mock_pfctl,
             (AF_INET6, 128, True, u'2404:6800:4004:80c::101f', 8080, 8080)],
         False,
         None,
-        63)
+        '0x01')
 
     assert mock_pfctl.mock_calls == [
         call('-s all'),
@@ -335,7 +335,7 @@ def test_setup_firewall_freebsd(mock_pf_get_dev, mock_ioctl, mock_pfctl,
                 (AF_INET, 32, True, u'1.2.3.66', 80, 80)],
             True,
             None,
-            63)
+            '0x01')
     assert str(excinfo.value) == 'UDP not supported by pf method_name'
     assert mock_pf_get_dev.mock_calls == []
     assert mock_ioctl.mock_calls == []
@@ -349,7 +349,7 @@ def test_setup_firewall_freebsd(mock_pf_get_dev, mock_ioctl, mock_pfctl,
             (AF_INET, 32, True, u'1.2.3.66', 80, 80)],
         False,
         None,
-        63)
+        '0x01')
     assert mock_ioctl.mock_calls == [
         call(mock_pf_get_dev(), 0xC4704433, ANY),
         call(mock_pf_get_dev(), 0xCBE0441A, ANY),
@@ -408,7 +408,7 @@ def test_setup_firewall_openbsd(mock_pf_get_dev, mock_ioctl, mock_pfctl):
             (AF_INET6, 128, True, u'2404:6800:4004:80c::101f', 8080, 8080)],
         False,
         None,
-        63)
+        '0x01')
 
     assert mock_ioctl.mock_calls == [
         call(mock_pf_get_dev(), 0xcd60441a, ANY),
@@ -445,7 +445,7 @@ def test_setup_firewall_openbsd(mock_pf_get_dev, mock_ioctl, mock_pfctl):
                 (AF_INET, 32, True, u'1.2.3.66', 80, 80)],
             True,
             None,
-            63)
+            '0x01')
     assert str(excinfo.value) == 'UDP not supported by pf method_name'
     assert mock_pf_get_dev.mock_calls == []
     assert mock_ioctl.mock_calls == []
@@ -459,7 +459,7 @@ def test_setup_firewall_openbsd(mock_pf_get_dev, mock_ioctl, mock_pfctl):
             (AF_INET, 32, True, u'1.2.3.66', 80, 80)],
         False,
         None,
-        63)
+        '0x01')
     assert mock_ioctl.mock_calls == [
         call(mock_pf_get_dev(), 0xcd60441a, ANY),
         call(mock_pf_get_dev(), 0xcd60441a, ANY),

tests/client/test_methods_tproxy.py

@@ -92,9 +92,8 @@ def test_firewall_command():
 
 
 @patch('sshuttle.methods.tproxy.ipt')
-@patch('sshuttle.methods.tproxy.ipt_ttl')
 @patch('sshuttle.methods.tproxy.ipt_chain_exists')
-def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
+def test_setup_firewall(mock_ipt_chain_exists, mock_ipt):
     mock_ipt_chain_exists.return_value = True
     method = get_method('tproxy')
     assert method.name == 'tproxy'
@@ -109,13 +108,12 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
             (AF_INET6, 128, True, u'2404:6800:4004:80c::101f', 8080, 8080)],
         True,
         None,
-        63)
+        '0x01')
     assert mock_ipt_chain_exists.mock_calls == [
         call(AF_INET6, 'mangle', 'sshuttle-m-1024'),
         call(AF_INET6, 'mangle', 'sshuttle-t-1024'),
         call(AF_INET6, 'mangle', 'sshuttle-d-1024')
     ]
-    assert mock_ipt_ttl.mock_calls == []
     assert mock_ipt.mock_calls == [
         call(AF_INET6, 'mangle', '-D', 'OUTPUT', '-j', 'sshuttle-m-1024'),
         call(AF_INET6, 'mangle', '-F', 'sshuttle-m-1024'),
@@ -139,17 +137,17 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
         call(AF_INET6, 'mangle', '-A', 'sshuttle-m-1024', '-j', 'RETURN',
              '-m', 'addrtype', '--dst-type', 'LOCAL'),
         call(AF_INET6, 'mangle', '-A', 'sshuttle-d-1024', '-j', 'MARK',
-             '--set-mark', '1'),
+             '--set-mark', '0x01'),
         call(AF_INET6, 'mangle', '-A', 'sshuttle-d-1024', '-j', 'ACCEPT'),
         call(AF_INET6, 'mangle', '-A', 'sshuttle-t-1024', '-m', 'socket',
              '-j', 'sshuttle-d-1024', '-m', 'tcp', '-p', 'tcp'),
         call(AF_INET6, 'mangle', '-A', 'sshuttle-t-1024', '-m', 'socket',
              '-j', 'sshuttle-d-1024', '-m', 'udp', '-p', 'udp'),
         call(AF_INET6, 'mangle', '-A', 'sshuttle-m-1024', '-j', 'MARK',
-             '--set-mark', '1', '--dest', u'2404:6800:4004:80c::33/32',
+             '--set-mark', '0x01', '--dest', u'2404:6800:4004:80c::33/32',
              '-m', 'udp', '-p', 'udp', '--dport', '53'),
         call(AF_INET6, 'mangle', '-A', 'sshuttle-t-1024', '-j', 'TPROXY',
-             '--tproxy-mark', '0x1/0x1',
+             '--tproxy-mark', '0x01',
              '--dest', u'2404:6800:4004:80c::33/32',
              '-m', 'udp', '-p', 'udp', '--dport', '53', '--on-port', '1026'),
         call(AF_INET6, 'mangle', '-A', 'sshuttle-m-1024', '-j', 'RETURN',
@@ -165,22 +163,23 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
              '--dest', u'2404:6800:4004:80c::101f/128',
              '-m', 'udp', '-p', 'udp', '--dport', '8080:8080'),
         call(AF_INET6, 'mangle', '-A', 'sshuttle-m-1024', '-j', 'MARK',
-             '--set-mark', '1', '--dest', u'2404:6800:4004:80c::/64',
+             '--set-mark', '0x01', '--dest', u'2404:6800:4004:80c::/64',
              '-m', 'tcp', '-p', 'tcp', '--dport', '8000:9000'),
         call(AF_INET6, 'mangle', '-A', 'sshuttle-t-1024', '-j', 'TPROXY',
-             '--tproxy-mark', '0x1/0x1', '--dest', u'2404:6800:4004:80c::/64',
+             '--tproxy-mark', '0x01', '--dest',
+             u'2404:6800:4004:80c::/64',
              '-m', 'tcp', '-p', 'tcp', '--dport', '8000:9000',
              '--on-port', '1024'),
         call(AF_INET6, 'mangle', '-A', 'sshuttle-m-1024', '-j', 'MARK',
-             '--set-mark', '1', '--dest', u'2404:6800:4004:80c::/64',
+             '--set-mark', '0x01', '--dest', u'2404:6800:4004:80c::/64',
              '-m', 'udp', '-p', 'udp', '--dport', '8000:9000'),
         call(AF_INET6, 'mangle', '-A', 'sshuttle-t-1024', '-j', 'TPROXY',
-             '--tproxy-mark', '0x1/0x1', '--dest', u'2404:6800:4004:80c::/64',
+             '--tproxy-mark', '0x01', '--dest',
+             u'2404:6800:4004:80c::/64',
              '-m', 'udp', '-p', 'udp', '--dport', '8000:9000',
              '--on-port', '1024')
     ]
     mock_ipt_chain_exists.reset_mock()
-    mock_ipt_ttl.reset_mock()
     mock_ipt.reset_mock()
 
     method.restore_firewall(1025, AF_INET6, True, None)
@@ -189,7 +188,6 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
         call(AF_INET6, 'mangle', 'sshuttle-t-1025'),
         call(AF_INET6, 'mangle', 'sshuttle-d-1025')
     ]
-    assert mock_ipt_ttl.mock_calls == []
     assert mock_ipt.mock_calls == [
         call(AF_INET6, 'mangle', '-D', 'OUTPUT', '-j', 'sshuttle-m-1025'),
         call(AF_INET6, 'mangle', '-F', 'sshuttle-m-1025'),
@@ -201,7 +199,6 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
         call(AF_INET6, 'mangle', '-X', 'sshuttle-d-1025')
     ]
     mock_ipt_chain_exists.reset_mock()
-    mock_ipt_ttl.reset_mock()
     mock_ipt.reset_mock()
 
     # IPV4
@@ -214,13 +211,12 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
             (AF_INET, 32, True, u'1.2.3.66', 80, 80)],
         True,
         None,
-        63)
+        '0x01')
     assert mock_ipt_chain_exists.mock_calls == [
         call(AF_INET, 'mangle', 'sshuttle-m-1025'),
         call(AF_INET, 'mangle', 'sshuttle-t-1025'),
         call(AF_INET, 'mangle', 'sshuttle-d-1025')
     ]
-    assert mock_ipt_ttl.mock_calls == []
     assert mock_ipt.mock_calls == [
         call(AF_INET, 'mangle', '-D', 'OUTPUT', '-j', 'sshuttle-m-1025'),
         call(AF_INET, 'mangle', '-F', 'sshuttle-m-1025'),
@@ -244,17 +240,17 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
         call(AF_INET, 'mangle', '-A', 'sshuttle-m-1025', '-j', 'RETURN',
              '-m', 'addrtype', '--dst-type', 'LOCAL'),
         call(AF_INET, 'mangle', '-A', 'sshuttle-d-1025',
-             '-j', 'MARK', '--set-mark', '1'),
+             '-j', 'MARK', '--set-mark', '0x01'),
         call(AF_INET, 'mangle', '-A', 'sshuttle-d-1025', '-j', 'ACCEPT'),
         call(AF_INET, 'mangle', '-A', 'sshuttle-t-1025', '-m', 'socket',
              '-j', 'sshuttle-d-1025', '-m', 'tcp', '-p', 'tcp'),
         call(AF_INET, 'mangle', '-A', 'sshuttle-t-1025', '-m', 'socket',
              '-j', 'sshuttle-d-1025', '-m', 'udp', '-p', 'udp'),
         call(AF_INET, 'mangle', '-A', 'sshuttle-m-1025', '-j', 'MARK',
-             '--set-mark', '1', '--dest', u'1.2.3.33/32',
+             '--set-mark', '0x01', '--dest', u'1.2.3.33/32',
              '-m', 'udp', '-p', 'udp', '--dport', '53'),
         call(AF_INET, 'mangle', '-A', 'sshuttle-t-1025', '-j', 'TPROXY',
-             '--tproxy-mark', '0x1/0x1', '--dest', u'1.2.3.33/32',
+             '--tproxy-mark', '0x01', '--dest', u'1.2.3.33/32',
              '-m', 'udp', '-p', 'udp', '--dport', '53', '--on-port', '1027'),
         call(AF_INET, 'mangle', '-A', 'sshuttle-m-1025', '-j', 'RETURN',
              '--dest', u'1.2.3.66/32', '-m', 'tcp', '-p', 'tcp',
@@ -269,20 +265,19 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
              '--dest', u'1.2.3.66/32', '-m', 'udp', '-p', 'udp',
              '--dport', '80:80'),
         call(AF_INET, 'mangle', '-A', 'sshuttle-m-1025', '-j', 'MARK',
-             '--set-mark', '1', '--dest', u'1.2.3.0/24',
+             '--set-mark', '0x01', '--dest', u'1.2.3.0/24',
              '-m', 'tcp', '-p', 'tcp'),
         call(AF_INET, 'mangle', '-A', 'sshuttle-t-1025', '-j', 'TPROXY',
-             '--tproxy-mark', '0x1/0x1', '--dest', u'1.2.3.0/24',
+             '--tproxy-mark', '0x01', '--dest', u'1.2.3.0/24',
              '-m', 'tcp', '-p', 'tcp', '--on-port', '1025'),
         call(AF_INET, 'mangle', '-A', 'sshuttle-m-1025', '-j', 'MARK',
-             '--set-mark', '1', '--dest', u'1.2.3.0/24',
+             '--set-mark', '0x01', '--dest', u'1.2.3.0/24',
              '-m', 'udp', '-p', 'udp'),
         call(AF_INET, 'mangle', '-A', 'sshuttle-t-1025', '-j', 'TPROXY',
-             '--tproxy-mark', '0x1/0x1', '--dest', u'1.2.3.0/24',
+             '--tproxy-mark', '0x01', '--dest', u'1.2.3.0/24',
              '-m', 'udp', '-p', 'udp', '--on-port', '1025')
     ]
     mock_ipt_chain_exists.reset_mock()
-    mock_ipt_ttl.reset_mock()
     mock_ipt.reset_mock()
 
     method.restore_firewall(1025, AF_INET, True, None)
@@ -291,7 +286,6 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
         call(AF_INET, 'mangle', 'sshuttle-t-1025'),
         call(AF_INET, 'mangle', 'sshuttle-d-1025')
     ]
-    assert mock_ipt_ttl.mock_calls == []
     assert mock_ipt.mock_calls == [
         call(AF_INET, 'mangle', '-D', 'OUTPUT', '-j', 'sshuttle-m-1025'),
         call(AF_INET, 'mangle', '-F', 'sshuttle-m-1025'),
@@ -303,5 +297,4 @@ def test_setup_firewall(mock_ipt_chain_exists, mock_ipt_ttl, mock_ipt):
         call(AF_INET, 'mangle', '-X', 'sshuttle-d-1025')
     ]
     mock_ipt_chain_exists.reset_mock()
-    mock_ipt_ttl.reset_mock()
     mock_ipt.reset_mock()