Set network configuration by hostname look-up

See PR #28

README.md

@@ -24,9 +24,9 @@ Launch it so:
 In the main window, you will be given a list of discovered devices. Clicking on one
 will show its configuration window.
 
-The most common operation is the setting of the hostname, and a simple window will
-pop up.  
-For further network settings, hit `Advanced`.
+The most common operation is the configuration of network setting from the hostname,
+and a simple window will pop up, if found in the DNS.  
+For further configuration, hit `Advanced`.
 
 The gui is further documented in [ipa_gui/gui.md](ipa_gui/gui.md)
 

ipa_gui/configurations.py

@@ -7,7 +7,7 @@
 
 from ipassign import Configuration, acknowledgements
 
-from .networking import gethostbyname, network
+from .networking import from_hostname, network
 
 # These are used to validate hostnames
 VALID_HN_CHARS = string.ascii_letters + string.digits + '-'
@@ -50,10 +50,11 @@ def display_config_window(config: Configuration = None) -> None:
 
 
 class HostnameWindow(QObject):
-    """HostnameWindow only allows the setting of a device's hostname.
+    """HostnameWindow sets a device's configuration from its hostname, by
+    performing look-ups.
 
-    Setting the hostname is the most common operation, and is ipassign's
-    default mode of operation.
+    Configuring network settings by hostname is the most common operation, and
+    is ipassign's default mode of operation.
 
     This mode of setting will write the configuration to flash and apply it
     dynamically.
@@ -118,7 +119,9 @@ def validator(self):
 
         if (content and all([c in VALID_HN_CHARS for c in content])
                 and not content.startswith('-')):
-            color = GREEN
+            ok, _ = from_hostname(content)
+            if ok:
+                color = GREEN
 
         if color is GREEN:
             self.pbApply.setEnabled(True)
@@ -138,11 +141,17 @@ def switch_mode(self):
 
     def apply(self):
         hostname = self.leHostname.text()
-        self.log.emit(f'Renaming {self._config.hostname} -> {hostname}')
+        self.log.emit(f'Resetting {self._config.hostname} -> {hostname}')
         self._config.hostname = hostname
         config, self._config = self._config, None
         self.parent.close()
 
+        # The hostname was already validated prior to enabling pbApply.
+        _, ret = from_hostname(hostname)
+        config.ip = ret['ip']
+        config.gw = ret['gw']
+        config.bc = ret['bc']
+        config.nm = ret['nm']
         config.flash = True
         config.dynamic = True
 
@@ -406,9 +415,16 @@ def show(self, config: Configuration) -> None:
         self.parent.show()
 
     def query_dns(self):
-        val = gethostbyname(self.leHostname.text())
-        if val:
-            self.leIP.setText(val)
+        ok, ret = from_hostname(self.leHostname.text())
+        if ok:
+            self.leIP.setText(ret['ip'])
+            self.leGateway.setText(ret['gw'])
+            self.leNetmask.setText(ret['nm'])
+            self.leBroadcast.setText(ret['bc'])
+        else:
+            # pbApply is purposefully not disabled here.
+            self.leHostname.setStyleSheet('QLineEdit { background-color: %s }'
+                                          % RED)
 
     def reset(self):
         self.show(self._config)

ipa_gui/gui.md

@@ -27,14 +27,17 @@ properties.
 
 ## HostnameWindow
 
-HostnameWindow only allows the setting of a device's hostname.  
-Setting the hostname is the most common operation, and is ipassign's default
-mode of operation.
+HostnameWindow sets a device's configuration from its hostname, by performing
+look-ups.
+Configuring network settings by hostname is the most common operation, and is
+passign's default mode of operation.
 
 The hostname is validated with respect to RFC 1123, section 2.1. If the
 hostname is not valid, the `Apply` button is disabled.
 
-The hostname will be written to flash and applied dynamically.
+If found in DNS, the hostname and its network settings will be written to flash
+and applied dynamically. 
+These settings are found by `networking.from_hostname`.
 
 The `Advanced` push-button allows to switch to the `NetworkWindow` view.  
 

ipa_gui/networking.py

@@ -1,7 +1,7 @@
 import socket
 import struct
 
-from typing import Union
+import netifaces
 
 from PyQt5.QtCore import pyqtSignal, QObject
 
@@ -113,8 +113,16 @@ def send_configuration(self, config: Configuration) -> commands:
 network = NetworkInterface()
 
 
-def gethostbyname(name: str) -> Union[bool, str]:
+def from_hostname(name: str) -> dict:
     try:
-        return socket.gethostbyname(name)
+        ip = socket.gethostbyname(name)
     except socket.gaierror:
-        return False
+        return False, 'Not a known hostname'
+
+    gw, iface = netifaces.gateways()['default'][netifaces.AF_INET]
+
+    info = netifaces.ifaddresses(iface)[netifaces.AF_INET][0]
+    nm = info['netmask']
+    bc = info['broadcast']
+
+    return True, {'ip': ip, 'gw': gw, 'nm': nm, 'bc': bc}

setup.py

@@ -5,15 +5,15 @@
 
 setup(
      name='icepap-ipassign',
-     version='2.2.0',
+     version='2.3.0',
      author='Cyril Danilevski',
      author_email='[email protected]',
      description='A tool to configure IcePAP network settings',
      long_description=long_description,
      long_description_content_type="text/markdown",
      url='https://github.com/cydanil/icepap-ipassign',
      packages=['ipassign', 'ipa_gui', 'ipa_utils'],
-     install_requires=['PyQt5>=5.12.0'],
+     install_requires=['PyQt5>=5.12.0', 'netifaces>=0.10.9'],
      tests_require=['pytest'],
      python_requires='>=3.7',
      entry_points={

tests/test_networking.py

@@ -1,19 +1,41 @@
 import os
 import socket
 import sys
+
+import netifaces
+
 sys.path.insert(0,
                 os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))
 
-from ipa_gui.networking import gethostbyname  # noqa : import not at top of file
+from ipa_gui.networking import from_hostname  # noqa : import not at top of file
 
 
-def test_gethostbyname():
-    def mock_call(val):
+def test_from_hostname():
+    def mock_socket(val):
         if val == 'known':
             return '172.24.1.105'
         raise socket.gaierror
+    setattr(socket, 'gethostbyname', mock_socket)
+
+    def mock_gateways():
+        return {'default': {2: ('172.24.154.1', 'eth0')}}
+    setattr(netifaces, 'gateways', mock_gateways)
+
+    def mock_ifaddresses(val):
+        return {17: [{'addr': '6c:2b:59:e8:5e:51',
+                      'broadcast': 'ff:ff:ff:ff:ff:ff'}],
+                2: [{'addr': '172.24.155.154',
+                     'netmask': '255.255.254.0',
+                     'broadcast': '172.24.155.255'}]}
+    setattr(netifaces, 'ifaddresses', mock_ifaddresses)
 
-    setattr(socket, 'gethostbyname', mock_call)
+    ok, val = from_hostname('known')
+    assert ok
+    assert val == {'ip': '172.24.1.105',
+                   'gw': '172.24.154.1',
+                   'nm': '255.255.254.0',
+                   'bc': '172.24.155.255'}
 
-    assert gethostbyname('known') == '172.24.1.105'
-    assert not gethostbyname('unknown')
+    ok, val = from_hostname('unknown')
+    assert not ok
+    assert val == 'Not a known hostname'