--- a/src/internet-stack/wscript	Fri Sep 05 18:42:59 2008 +0100
+++ b/src/internet-stack/wscript	Fri Sep 05 19:55:21 2008 +0100
@@ -1,9 +1,23 @@
 ## -*- Mode: python; py-indent-offset: 4; indent-tabs-mode: nil; coding: utf-8; -*-
 import Params
+import Task
 import os
 
 # Mercurial repository of the network simulation cradle
 NETWORK_SIMULATION_CRADLE_REPO = "https://secure.wand.net.nz/mercurial/nsc"
+
+# directory that contains network simulation cradle source
+# note, this path is relative to the project root
+NSC_DIR = "nsc"
+
+
+def set_options(opt):
+    opt.add_option('--nsc',
+                   help=('Enable Network Simulation Cradle to allow the use real-world network stacks'),
+                   action="store_true", default=False,
+                   dest='nsc')
+
+
 def nsc_fetch():
     def nsc_clone():
         print "Retrieving nsc from " + NETWORK_SIMULATION_CRADLE_REPO
@@ -62,6 +76,38 @@
     nsc_fetch()
 
 
+
+class NscBuildTask(Task.TaskBase):
+    """task that builds nsc
+    """
+    def __init__(self, builddir):
+        self.m_display = 'build-nsc'
+        self.prio = 1000 # build after the rest of ns-3
+        self.builddir = builddir
+        super(NscBuildTask, self).__init__()
+
+    def run(self):
+        # XXX: Detect gcc major version(s) available to build supported stacks
+        kernels = [['linux-2.6.18', 'linux2.6.18'],
+                   ['linux-2.6.26', 'linux2.6.26']]
+        for dir, name in kernels:
+            soname = 'lib' + name + '.so'
+            if not os.path.exists(os.path.join("..", NSC_DIR, dir, soname)):
+                if os.system('cd ../%s && python scons.py %s' % (NSC_DIR, dir)) != 0:
+                    Params.fatal("Building NSC stack failed")
+        builddir = self.builddir
+        if not os.path.exists(builddir + '/nsc'):
+            try:
+                os.symlink('../../' + NSC_DIR, builddir + '/nsc')
+            except:
+                Params.fatal("Error linkink " + builddir + '/nsc')
+        if not os.path.exists(builddir + '/' + soname):
+            try:
+                os.symlink('../../' + NSC_DIR + '/' + dir + '/' + soname, builddir +  '/' + soname)
+            except:
+                Params.fatal("Error linking " + builddir + '/' + soname)
+        
+
 def build(bld):
     obj = bld.create_ns3_module('internet-stack', ['node'])
     obj.source = [
@@ -110,3 +156,6 @@
         obj.source.append ('nsc-tcp-socket-factory-impl.cc')
         obj.source.append ('nsc-sysctl.cc')
         obj.uselib = 'DL'
+        
+        builddir = os.path.abspath(os.path.join(bld.env()['NS3_BUILDDIR'], bld.env ().variant()))
+        NscBuildTask(builddir)

--- a/wscript	Fri Sep 05 18:42:59 2008 +0100
+++ b/wscript	Fri Sep 05 19:55:21 2008 +0100
@@ -55,8 +55,6 @@
 #
 TRACEBALL_SUFFIX = ".tar.bz2"
 
-# directory that contains network simulation cradle source
-NSC_DIR = "nsc"
 
 def dist_hook():
     import tarfile
@@ -168,14 +166,11 @@
                    help=('For regression testing, only run/generate the indicated regression tests, '
                          'specified as a comma separated list of test names'),
                    dest='regression_tests', type="string")
-    opt.add_option('--nsc',
-                   help=('Enable Network Simulation Cradle to allow the use real-world network stacks'),
-                   action="store_true", default=False,
-                   dest='nsc')
 
     # options provided in a script in a subdirectory named "src"
     opt.sub_options('src')
     opt.sub_options('bindings/python')
+    opt.sub_options('src/internet-stack')
 
 
 def check_compilation_flag(conf, flag):
@@ -329,28 +324,6 @@
     return stat >> 8
 
 
-def nsc_build(bld):
-    # XXX: Detect gcc major version(s) available to build supported stacks
-    kernels = [['linux-2.6.18', 'linux2.6.18'],
-               ['linux-2.6.26', 'linux2.6.26']]
-    for dir,name in kernels:
-        soname = 'lib' + name + '.so'
-        tmp = NSC_DIR + '/' + dir +'/' + soname
-        if not os.path.exists(tmp):
-            if os.system('cd ' + NSC_DIR + ' && python scons.py ' + dir) != 0:
-                Params.fatal("Building NSC stack failed")
-        builddir = os.path.abspath(os.path.join(bld.env()['NS3_BUILDDIR'], bld.env ().variant()))
-        if not os.path.exists(builddir + '/nsc'):
-            try:
-                os.symlink('../../' + NSC_DIR, builddir + '/nsc')
-            except:
-                Params.fatal("Error linkink " + builddir + '/nsc')
-        if not os.path.exists(builddir + '/' + soname):
-            try:
-                os.symlink('../../' + NSC_DIR + '/' + dir + '/' + soname, builddir +  '/' + soname)
-            except:
-                Params.fatal("Error linking " + builddir + '/' + soname)
-
 def build(bld):
     if Params.g_options.no_task_lines:
         import Runner
@@ -440,8 +413,6 @@
 
     bld.add_subdirs('bindings/python')
 
-    if env['NSC_ENABLED'] == 'yes':
-        nsc_build(bld)
 
 def get_command_template(*arguments):
     if Params.g_options.valgrind: