Improved network interface detection on POSIX systems

git-svn-id: https://linkchecker.svn.sourceforge.net/svnroot/linkchecker/trunk/linkchecker@3792 e7d03fd6-7b0d-0410-9947-9c21f3af8025

ChangeLog.txt

@@ -26,6 +26,10 @@
     Changed: linkchecker, linkcheck/checker/urlbase.py
     Added: linkcheck/clamav.py
 
+  * Improved network interface detection on POSIX systems.
+    Type: bugfix
+    Added: linkcheck/network/*
+
 4.9 "Michael Clayton" (released 25.4.2008)
 
   * Parse Shockwave Flash (SWF) for URLs to check

Makefile

@@ -59,6 +59,7 @@ localbuild: MANIFEST
 	$(PYTHON) setup.py build
 	cp -f build/lib.linux-$(MACHINE)-$(PYVER)/linkcheck/HtmlParser/htmlsax.so linkcheck/HtmlParser
 	cp -f build/lib.linux-$(MACHINE)-$(PYVER)/linkcheck/ftpparse/_ftpparse.so linkcheck/ftpparse
+	cp -f build/lib.linux-$(MACHINE)-$(PYVER)/linkcheck/network/_network.so linkcheck/network
 
 .PHONY: deb_orig
 deb_orig:

linkcheck/dns/__init__.py

@@ -20,7 +20,6 @@ __all__ = [
     'dnssec',
     'exception',
     'flags',
-    'ifconfig',
     'inet',
     'ipv4',
     'ipv6',

linkcheck/dns/resolver.py

@@ -22,6 +22,7 @@
 import socket
 import sets
 import sys
+import os
 import time
 import encodings.idna
 
@@ -377,11 +378,11 @@ class Resolver(object):
         @return: list of IP addresses
         @rtype: list of strings
         """
-        if not sys.platform.startswith('linux'):
-            # only Linux is supported right now
+        if os.name != 'posix':
+            # only POSIX is supported right now
             return []
-        import linkcheck.dns.ifconfig
-        ifc = linkcheck.dns.ifconfig.IfConfig()
+        from linkcheck.network import IfConfig
+        ifc = IfConfig()
         return [ifc.getAddr(iface) for iface in ifc.getInterfaceList() \
                 if ifc.isUp(iface)]
 

linkcheck/network/__init__.py

@@ -1,12 +1,12 @@
 # -*- coding: iso-8859-1 -*-
 """from http://twistedmatrix.com/wiki/python/IfConfig
 """
-
 import socket
 import errno
 import array
 import fcntl
 import struct
+from _network import ifreq_size
 from .. import log, LOG_DNS
 
 
@@ -40,14 +40,20 @@ class IfConfig (object):
     def __init__ (self):
         # create a socket so we have a handle to query
         self.sockfd = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        # Note that sizeof(struct ifreq) is not always 32
+        # (eg. on *BSD, x86_64 Linux) Thus the function call.
+        self.ifr_size = ifreq_size()
 
     def _ioctl (self, func, args):
         return fcntl.ioctl(self.sockfd.fileno(), func, args)
 
+    def _getifreq (self, ifname):
+        """Return ifreq buffer for given interface name."""
+        return struct.pack("%ds" % self.ifr_size, ifname)
+
     def _getaddr (self, ifname, func):
-        ifreq = struct.pack("32s", ifname)
         try:
-            result = self._ioctl(func, ifreq)
+            result = self._ioctl(func, self._getifreq(ifname))
         except IOError, msg:
             log.warn(LOG_DNS,
                   "error getting addr for interface %r: %s", ifname, msg)
@@ -55,9 +61,7 @@ class IfConfig (object):
         return socket.inet_ntoa(result[20:24])
 
     def getInterfaceList (self):
-        """
-        Get all interface names in a list.
-        """
+        """Get all interface names in a list."""
         # initial 8kB buffer to hold interface data
         bufsize = 8192
         # 80kB buffer should be enough for most boxen
@@ -80,22 +84,18 @@ class IfConfig (object):
         size, ptr = struct.unpack("iP", result)
         i = 0
         while i < size:
-            # XXX on *BSD, struct ifreq is not hardcoded 32, but dynamic.
-            ifreq_size = 32
-            ifconf = data[i:i+ifreq_size]
-            name, dummy = struct.unpack("16s16s", ifconf)
-            name, dummy = name.split('\0', 1)
-            iflist.append(name)
-            i += ifreq_size
+            ifconf = data[i:i+self.ifr_size]
+            name = struct.unpack("16s%ds" % (self.ifr_size-16), ifconf)[0]
+            name = name.split('\0', 1)[0]
+            if name:
+                iflist.append(name)
+            i += self.ifr_size
         return iflist
 
     def getFlags (self, ifname):
-        """
-        Get the flags for an interface
-        """
-        ifreq = struct.pack("32s", ifname)
+        """Get the flags for an interface"""
         try:
-            result = self._ioctl(self.SIOCGIFFLAGS, ifreq)
+            result = self._ioctl(self.SIOCGIFFLAGS, self._getifreq(ifname))
         except IOError, msg:
             log.warn(LOG_DNS,
                  "error getting flags for interface %r: %s", ifname, msg)
@@ -106,40 +106,35 @@ class IfConfig (object):
         return flags
 
     def getAddr (self, ifname):
-        """
-        Get the inet addr for an interface.
+        """Get the inet addr for an interface.
         @param ifname: interface name
         @type ifname: string
         """
         return self._getaddr(ifname, self.SIOCGIFADDR)
 
     def getMask (self, ifname):
-        """
-        Get the netmask for an interface.
+        """Get the netmask for an interface.
         @param ifname: interface name
         @type ifname: string
         """
         return self._getaddr(ifname, self.SIOCGIFNETMASK)
 
     def getBroadcast (self, ifname):
-        """
-        Get the broadcast addr for an interface.
+        """Get the broadcast addr for an interface.
         @param ifname: interface name
         @type ifname: string
         """
         return self._getaddr(ifname, self.SIOCGIFBRDADDR)
 
     def isUp (self, ifname):
-        """
-        Check whether interface is UP.
+        """Check whether interface is UP.
         @param ifname: interface name
         @type ifname: string
         """
         return (self.getFlags(ifname) & self.IFF_UP) != 0
 
     def isLoopback (self, ifname):
-        """
-        Check whether interface is a loopback device.
+        """Check whether interface is a loopback device.
         @param ifname: interface name
         @type ifname: string
         """

linkcheck/network/_network.c

@@ -0,0 +1,44 @@
+/* Copyright (C) 2000-2008 Bastian Kleineidam
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "Python.h"
+#include <sys/ioctl.h>
+#include <net/if.h>  
+
+
+/* The struct ifreq size varies on different platforms, so we need
+ this helper function to determine the size of it.
+ */
+static PyObject* network_ifreq_size (PyObject* self, PyObject* args)
+{
+    if (!PyArg_ParseTuple(args, ""))
+        return NULL;
+    return Py_BuildValue("i", sizeof(struct ifreq));
+}
+
+
+static PyMethodDef _functions[] = {
+    {"ifreq_size",  network_ifreq_size, METH_VARARGS,
+     "Return sizeof(struct ifreq)."},
+    {NULL, NULL, 0, NULL}        /* Sentinel */
+};
+
+
+PyMODINIT_FUNC init_network(void)
+{
+    (void) Py_InitModule("_network", _functions);
+}

setup.py

@@ -507,7 +507,8 @@ o a (Fast)CGI web interface (requires HTTP server)
                    'linkcheck.cache', 'linkcheck.htmlutil',
                    'linkcheck.dns', 'linkcheck.dns.rdtypes',
                    'linkcheck.dns.rdtypes.ANY', 'linkcheck.dns.rdtypes.IN',
-                   'linkcheck.HtmlParser', 'linkcheck.ftpparse', ],
+                   'linkcheck.HtmlParser', 'linkcheck.ftpparse',
+                   'linkcheck.network', ],
        ext_modules = [Extension('linkcheck.HtmlParser.htmlsax',
                   sources = ['linkcheck/HtmlParser/htmllex.c',
                    'linkcheck/HtmlParser/htmlparse.c',
@@ -520,6 +521,14 @@ o a (Fast)CGI web interface (requires HTTP server)
                   include_dirs = include_dirs + \
                                   [normpath("linkcheck/HtmlParser")],
                   ),
+                  Extension("linkcheck.network._network",
+                        ["linkcheck/network/_network.c",],
+                  extra_compile_args = extra_compile_args,
+                  library_dirs = library_dirs,
+                  libraries = libraries,
+                  define_macros = define_macros,
+                  include_dirs = include_dirs,
+                  ),
                   Extension("linkcheck.ftpparse._ftpparse",
                         ["linkcheck/ftpparse/_ftpparse.c",
                          "linkcheck/ftpparse/ftpparse.c"],

tests/test_network.py

@@ -0,0 +1,42 @@
+# -*- coding: iso-8859-1 -*-
+# Copyright (C) 2008 Bastian Kleineidam
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+"""
+Test network functions.
+"""
+
+import unittest
+import linkcheck.network
+
+
+class TestNetwork (unittest.TestCase):
+    """Test network functions."""
+
+    def test_ifreq_size (self):
+        self.assertTrue(linkcheck.network.ifreq_size() > 0)
+
+    def test_interfaces (self):
+        ifc = linkcheck.network.IfConfig()
+        ifc.getInterfaceList()
+
+
+def test_suite ():
+    """Build and return a TestSuite."""
+    return unittest.makeSuite(TestNetwork)
+
+
+if __name__ == '__main__':
+    unittest.main()