[Common] Add is_interface to validate network interfaces

Libtorrent now supports interface names instead of just IP address so
add new common functions to validate user input.

* Added is_interface that will verify if a libtorrent interface of name
or IP address.
* Added is_interface_name to verify that the name supplied is a valid
network interface name in the operating system.
  On Windows sock.if_nameindex() is only supported on 3.8+ and does not
return a uuid (required by libtorrent) so use ifaddr package. Using git
commit version for ifaddr due to adapter name decode bug in v0.1.7.
On other OSes attempt to use stdlib and fallback to ifaddr if installed
otherwiser return True.
* Added tests for is_interface & is_interface_name
* Updated UIs with change from address to interface
* Updated is_ipv6 and is_ipv4 to used inet_pton; now supported on
Windows.

Ref: https://github.com/pydron/ifaddr/pull/32
Closes: https://github.com/deluge-torrent/deluge/pull/338

10 files changed, 154 insertions, 34 deletions

diff --git a/DEPENDS.md b/DEPENDS.md
index 31fdfd0c3..197556dd0 100644
--- a/DEPENDS.md
+++ b/DEPENDS.md
@@ -28,6 +28,7 @@ All modules will require the [common](#common) section dependencies.
 - [setproctitle] - Optional: Renaming processes.
 - [Pillow] - Optional: Support for resizing tracker icons.
 - [dbus-python] - Optional: Show item location in filemanager.
+- [ifaddr] - Optional: Verify network interfaces.
 
 ### Linux and BSD
 
@@ -96,3 +97,4 @@ All modules will require the [common](#common) section dependencies.
 [libnotify]: https://developer.gnome.org/libnotify/
 [python-appindicator]: https://packages.ubuntu.com/xenial/python-appindicator
 [librsvg]: https://wiki.gnome.org/action/show/Projects/LibRsvg
+[ifaddr]: https://pypi.org/project/ifaddr/
diff --git a/deluge/common.py b/deluge/common.py
index da056d484..82adb0715 100644
--- a/deluge/common.py
+++ b/deluge/common.py
@@ -17,6 +17,7 @@ import numbers
 import os
 import platform
 import re
+import socket
 import subprocess
 import sys
 import tarfile
@@ -44,6 +45,11 @@ if platform.system() in ('Windows', 'Microsoft'):
 
     os.environ['SSL_CERT_FILE'] = where()
 
+try:
+    import ifaddr
+except ImportError:
+    ifaddr = None
+
 
 if platform.system() not in ('Windows', 'Microsoft', 'Darwin'):
     # gi makes dbus available on Window but don't import it as unused.
@@ -900,6 +906,29 @@ def free_space(path):
         return disk_data.f_bavail * block_size
 
 
+def is_interface(interface):
+    """Check if interface is a valid IP or network adapter.
+
+    Args:
+        interface (str): The IP or interface name to test.
+
+    Returns:
+        bool: Whether interface is valid is not.
+
+    Examples:
+        Windows:
+        >>> is_interface('{7A30AE62-23ZA-3744-Z844-A5B042524871}')
+        >>> is_interface('127.0.0.1')
+        True
+        Linux:
+        >>> is_interface('lo')
+        >>> is_interface('127.0.0.1')
+        True
+
+    """
+    return is_ip(interface) or is_interface_name(interface)
+
+
 def is_ip(ip):
     """A test to see if 'ip' is a valid IPv4 or IPv6 address.
 
@@ -935,15 +964,12 @@ def is_ipv4(ip):
 
     """
 
-    import socket
-
     try:
-        if windows_check():
-            return socket.inet_aton(ip)
-        else:
-            return socket.inet_pton(socket.AF_INET, ip)
+        socket.inet_pton(socket.AF_INET, ip)
     except OSError:
         return False
+    else:
+        return True
 
 
 def is_ipv6(ip):
@@ -962,23 +988,51 @@ def is_ipv6(ip):
     """
 
     try:
-        import ipaddress
-    except ImportError:
-        import socket
-
-        try:
-            return socket.inet_pton(socket.AF_INET6, ip)
-        except (OSError, AttributeError):
-            if windows_check():
-                log.warning('Unable to verify IPv6 Address on Windows.')
-                return True
+        socket.inet_pton(socket.AF_INET6, ip)
+    except OSError:
+        return False
     else:
+        return True
+
+
+def is_interface_name(name):
+    """Returns True if an interface name exists.
+
+    Args:
+        name (str): The Interface to test. eg. eth0 linux. GUID on Windows.
+
+    Returns:
+        bool: Whether name is valid or not.
+
+    Examples:
+        >>> is_interface_name("eth0")
+        True
+        >>> is_interface_name("{7A30AE62-23ZA-3744-Z844-A5B042524871}")
+        True
+
+    """
+
+    if not windows_check():
         try:
-            return ipaddress.IPv6Address(decode_bytes(ip))
-        except ipaddress.AddressValueError:
+            socket.if_nametoindex(name)
+        except OSError:
             pass
+        else:
+            return True
+
+    if ifaddr:
+        try:
+            adapters = ifaddr.get_adapters()
+        except OSError:
+            return True
+        else:
+            return any([name == a.name for a in adapters])
+
+    if windows_check():
+        regex = '^{[0-9A-Z]{8}-([0-9A-Z]{4}-){3}[0-9A-Z]{12}}$'
+        return bool(re.search(regex, str(name)))
 
-    return False
+    return True
 
 
 def decode_bytes(byte_str, encoding='utf8'):
diff --git a/deluge/core/core.py b/deluge/core/core.py
index a763b8d2f..1090b0f2a 100644
--- a/deluge/core/core.py
+++ b/deluge/core/core.py
@@ -164,19 +164,25 @@ class Core(component.Component):
         # store the one in the config so we can restore it on shutdown
         self._old_listen_interface = None
         if listen_interface:
-            if deluge.common.is_ip(listen_interface):
+            if deluge.common.is_interface(listen_interface):
                 self._old_listen_interface = self.config['listen_interface']
                 self.config['listen_interface'] = listen_interface
             else:
                 log.error(
-                    'Invalid listen interface (must be IP Address): %s',
+                    'Invalid listen interface (must be IP Address or Interface Name): %s',
                     listen_interface,
                 )
 
         self._old_outgoing_interface = None
         if outgoing_interface:
-            self._old_outgoing_interface = self.config['outgoing_interface']
-            self.config['outgoing_interface'] = outgoing_interface
+            if deluge.common.is_interface(outgoing_interface):
+                self._old_outgoing_interface = self.config['outgoing_interface']
+                self.config['outgoing_interface'] = outgoing_interface
+            else:
+                log.error(
+                    'Invalid outgoing interface (must be IP Address or Interface Name): %s',
+                    outgoing_interface,
+                )
 
         # New release check information
         self.__new_release = None
diff --git a/deluge/tests/test_common.py b/deluge/tests/test_common.py
index ccb468cb9..26d72e1ac 100644
--- a/deluge/tests/test_common.py
+++ b/deluge/tests/test_common.py
@@ -21,6 +21,8 @@ from deluge.common import (
     ftime,
     get_path_size,
     is_infohash,
+    is_interface,
+    is_interface_name,
     is_ip,
     is_ipv4,
     is_ipv6,
@@ -116,6 +118,55 @@ class CommonTestCase(unittest.TestCase):
         self.assertTrue(is_ipv6('2001:db8::'))
         self.assertFalse(is_ipv6('2001:db8:'))
 
+    def get_windows_interface_name(self):
+        import winreg
+
+        # find a network card in the registery
+        with winreg.OpenKey(
+            winreg.HKEY_LOCAL_MACHINE,
+            r'SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkCards',
+        ) as key:
+            self.assertTrue(
+                winreg.QueryInfoKey(key)[0] > 0
+            )  # must have at least 1 network card
+            network_card = winreg.EnumKey(key, 0)
+        # get GUID of network card
+        with winreg.OpenKey(
+            winreg.HKEY_LOCAL_MACHINE,
+            fr'SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkCards\{network_card}',
+        ) as key:
+            for i in range(1):
+                value = winreg.EnumValue(key, i)
+                if value[0] == 'ServiceName':
+                    interface_name = value[1]
+        return interface_name
+
+    def test_is_interface_name(self):
+        if windows_check():
+            interface_name = self.get_windows_interface_name()
+            self.assertFalse(is_interface_name('2001:db8:'))
+            self.assertFalse(
+                is_interface_name('{THIS0000-IS00-ONLY-FOR0-TESTING00000}')
+            )
+            self.assertTrue(is_interface_name(interface_name))
+        else:
+            self.assertTrue(is_interface_name('lo'))
+            self.assertFalse(is_interface_name('127.0.0.1'))
+            self.assertFalse(is_interface_name('eth01101'))
+
+    def test_is_interface(self):
+        if windows_check():
+            interface_name = self.get_windows_interface_name()
+            self.assertTrue(is_interface('127.0.0.1'))
+            self.assertTrue(is_interface(interface_name))
+            self.assertFalse(is_interface('127'))
+            self.assertFalse(is_interface('{THIS0000-IS00-ONLY-FOR0-TESTING00000}'))
+        else:
+            self.assertTrue(is_interface('lo'))
+            self.assertTrue(is_interface('127.0.0.1'))
+            self.assertFalse(is_interface('127.'))
+            self.assertFalse(is_interface('eth01101'))
+
     def test_version_split(self):
         self.assertTrue(VersionSplit('1.2.2') == VersionSplit('1.2.2'))
         self.assertTrue(VersionSplit('1.2.1') < VersionSplit('1.2.2'))
diff --git a/deluge/ui/console/modes/preferences/preference_panes.py b/deluge/ui/console/modes/preferences/preference_panes.py
index 4471580eb..b47bc4b07 100644
--- a/deluge/ui/console/modes/preferences/preference_panes.py
+++ b/deluge/ui/console/modes/preferences/preference_panes.py
@@ -8,7 +8,7 @@
 
 import logging
 
-from deluge.common import is_ip
+from deluge.common import is_interface
 from deluge.decorators import overrides
 from deluge.i18n import get_languages
 from deluge.ui.client import client
@@ -91,11 +91,12 @@ class BasePreferencePane(BaseInputPane, BaseWindow, PopupsHandler):
                     )
                 elif ipt.name == 'listen_interface':
                     listen_interface = ipt.get_value().strip()
-                    if is_ip(listen_interface) or not listen_interface:
+                    if is_interface(listen_interface) or not listen_interface:
                         conf_dict['listen_interface'] = listen_interface
                 elif ipt.name == 'outgoing_interface':
                     outgoing_interface = ipt.get_value().strip()
-                    conf_dict['outgoing_interface'] = outgoing_interface
+                    if is_interface(outgoing_interface) or not outgoing_interface:
+                        conf_dict['outgoing_interface'] = outgoing_interface
                 elif ipt.name.startswith('proxy_'):
                     if ipt.name == 'proxy_type':
                         conf_dict.setdefault('proxy', {})['type'] = ipt.get_value()
diff --git a/deluge/ui/gtk3/glade/preferences_dialog.ui b/deluge/ui/gtk3/glade/preferences_dialog.ui
index df56c4419..ae9ae98a3 100644
--- a/deluge/ui/gtk3/glade/preferences_dialog.ui
+++ b/deluge/ui/gtk3/glade/preferences_dialog.ui
@@ -2573,8 +2573,8 @@ used sparingly.</property>
                                       <object class="GtkEntry" id="entry_interface">
                                         <property name="visible">True</property>
                                         <property name="can_focus">True</property>
-                                        <property name="tooltip_text" translatable="yes">The IP address of the interface to listen for incoming bittorrent connections on. Leave this empty if you want to use the default.</property>
-                                        <property name="max_length">15</property>
+                                        <property name="tooltip_text" translatable="yes">IP address or network interface name to listen for incoming BitTorrent connections. Leave empty to use system default.</property>
+                                        <property name="max_length">40</property>
                                         <property name="width_chars">15</property>
                                         <property name="truncate_multiline">True</property>
                                         <property name="primary_icon_activatable">False</property>
@@ -2587,7 +2587,7 @@ used sparingly.</property>
                                   <object class="GtkLabel" id="label110">
                                     <property name="visible">True</property>
                                     <property name="can_focus">False</property>
-                                    <property name="label" translatable="yes">Incoming Address</property>
+                                    <property name="label" translatable="yes">Incoming Interface</property>
                                     <attributes>
                                       <attribute name="weight" value="bold"/>
                                     </attributes>
@@ -2812,9 +2812,9 @@ used sparingly.</property>
                                         <property name="visible">True</property>
                                         <property name="can_focus">True</property>
                                         <property name="tooltip_text" translatable="yes">
-The network interface name or IP address for outgoing BitTorrent connections. (Leave empty for default.)
+                                          IP address or network interface name for outgoing BitTorrent connections. Leave empty to use system default.
                                         </property>
-                                        <property name="max_length">15</property>
+                                        <property name="max_length">40</property>
                                         <property name="invisible_char">●</property>
                                         <property name="width_chars">15</property>
                                         <property name="truncate_multiline">True</property>
diff --git a/deluge/ui/gtk3/preferences.py b/deluge/ui/gtk3/preferences.py
index a1a986414..1ffa07ce5 100644
--- a/deluge/ui/gtk3/preferences.py
+++ b/deluge/ui/gtk3/preferences.py
@@ -671,11 +671,15 @@ class Preferences(component.Component):
             'chk_random_outgoing_ports'
         ).get_active()
         incoming_address = self.builder.get_object('entry_interface').get_text().strip()
-        if deluge.common.is_ip(incoming_address) or not incoming_address:
+        if deluge.common.is_interface(incoming_address) or not incoming_address:
             new_core_config['listen_interface'] = incoming_address
-        new_core_config['outgoing_interface'] = (
+        outgoing_address = (
             self.builder.get_object('entry_outgoing_interface').get_text().strip()
         )
+        if deluge.common.is_interface(outgoing_address) or not outgoing_address:
+            new_core_config['outgoing_interface'] = (
+                self.builder.get_object('entry_outgoing_interface').get_text().strip()
+            )
         new_core_config['peer_tos'] = self.builder.get_object(
             'entry_peer_tos'
         ).get_text()
diff --git a/packaging/win/delugewin.spec b/packaging/win/delugewin.spec
index f79f041b1..9dadca244 100644
--- a/packaging/win/delugewin.spec
+++ b/packaging/win/delugewin.spec
@@ -6,7 +6,7 @@ from PyInstaller.utils.hooks import collect_all, collect_submodules, copy_metada
 
 datas = []
 binaries = []
-hiddenimports = ['pygame']
+hiddenimports = ['pygame','ifaddr']
 
 # Collect Meta Data
 datas += copy_metadata('deluge', recursive=True)
diff --git a/requirements.txt b/requirements.txt
index 655595d98..2d1a1298f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -13,3 +13,4 @@ windows-curses; sys_platform == 'win32'
 zope.interface>=4.4.2
 distro; 'linux' in sys_platform or 'bsd' in sys_platform
 pygeoip
+https://github.com/pydron/ifaddr/archive/37cb5334f392f12811d38d90ec891746e3247c76.zip
diff --git a/setup.py b/setup.py
index a939ebd29..202223503 100755
--- a/setup.py
+++ b/setup.py
@@ -549,6 +549,7 @@ extras_require = {
         'setproctitle',
         'pillow',
         'chardet',
+        'ifaddr',
     ]
 }