dom0: move network-attach logic to qubes.py

Main reason is to remove code duplication.
Also fixes #260 and workaround (by sleep...) some race at NetVM restart
(fronted driver does not noticed vif-detach+vif-attach).

dom0/qvm-core/qubes.py

@@ -942,6 +942,44 @@ class QubesVm(object):
 
         return conf
 
+    def attach_network(self, verbose = False, wait = True, netvm = None):
+        if dry_run:
+            return
+
+        if not self.is_running():
+            raise QubesException ("VM not running!")
+
+        if netvm is None:
+            netvm = self.netvm_vm
+
+        if netvm is None:
+            raise QubesException ("NetVM not set!")
+
+        if netvm.qid != 0:
+            if not netvm.is_running():
+                if verbose:
+                    print "--> Starting NetVM {0}...".format(netvm.name)
+                netvm.start()
+
+        xs_path = '/local/domain/%d/device/vif/0/state' % (self.xid)
+        if xs.read('', xs_path) is not None:
+            # TODO: check its state and backend state (this can be stale vif after NetVM restart)
+            if verbose:
+                print "NOTICE: Network already attached"
+                return
+
+        xm_cmdline = ["/usr/sbin/xl", "network-attach", str(self.xid), "script=/etc/xen/scripts/vif-route-qubes", "ip="+self.ip, "backend="+netvm.name ]
+        retcode = subprocess.call (xm_cmdline)
+        if retcode != 0:
+            print ("WARNING: Cannot attach to network to '{0}'!".format(self.name))
+        if wait:
+            tries = 0
+            while xs.read('', xs_path) != '4':
+                tries += 1
+                if tries > 50:
+                    raise QubesException ("Network attach timed out!")
+                time.sleep(0.2)
+
     def start(self, debug_console = False, verbose = False, preparing_dvm = False):
         if dry_run:
             return
@@ -1424,10 +1462,14 @@ class QubesNetVm(QubesVm):
             # Cleanup stale VIFs
             vm.cleanup_vifs()
 
-            xm_cmdline = ["/usr/sbin/xl", "network-attach", vm.name, "script=/etc/xen/scripts/vif-route-qubes", "ip="+vm.ip, "backend="+self.name ]
-            retcode = subprocess.call (xm_cmdline)
-            if retcode != 0:
-                print ("WARNING: Cannot attach to network to '{0}'!".format(vm.name))
+            # wait for frontend to forget about this device (UGLY HACK)
+            time.sleep(0.1)
+
+            try:
+                vm.attach_network(wait=False)
+            except QubesException as ex:
+                print ("WARNING: Cannot attach to network to '{0}': {1}".format(vm.name, ex))
+
         return xid
 
     def add_external_ip_permission(self, xid):
@@ -1603,6 +1645,10 @@ class QubesDom0NetVm(QubesNetVm):
     def get_private_img_sz(self):
         return 0
 
+    @property
+    def ip(self):
+        return "10.137.0.1"
+
     def start(self, debug_console = False, verbose = False):
         raise QubesException ("Cannot start Dom0 fake domain!")
 

dom0/qvm-tools/qvm-dom0-network-via-netvm

@@ -25,7 +25,10 @@ import os.path
 import os
 import sys
 
+qvm_collection = None
+
 def get_netvm():
+    global qvm_collection
     qvm_collection = QubesVmCollection()
     qvm_collection.lock_db_for_reading()
     qvm_collection.load()
@@ -59,12 +62,11 @@ def netup():
     if os.path.isfile('/var/lock/subsys/NetworkManager'):
         os.system('/etc/init.d/NetworkManager stop')
     if not vif_eth0_exists():
-        cmd = 'modprobe xennet && xl network-attach 0 ip=10.137.0.1 backend='
-        cmd += netvm.name
-        cmd += ' script=/etc/xen/scripts/vif-route-qubes'
+        cmd = 'modprobe xennet'
         if os.system(cmd) != 0:
             print 'Error creating network device'
             sys.exit(1)
+        qvm_collection[0].attach_network(verbose=True, netvm=netvm, wait=True)
     if not bringup_eth0(netvm):
         sys.exit(1)
 

dom0/qvm-tools/qvm-prefs

@@ -128,22 +128,15 @@ def set_netvm(vms, vm, args):
     vm.netvm_vm = netvm_vm
     if not vm.is_running():
         return
+    # this can fail if VM was not connected to any NetVM
+    subprocess.call(["xl", "network-detach", vm.name, "0"], stderr=subprocess.PIPE)
+    if vm.netvm_vm is None:
+        return
     if not vm.netvm_vm.is_running():
         subprocess.check_call(["qvm-start", vm.netvm_vm.name])
-    subprocess.check_call(["xl", "network-detach", vm.name, "0"])
-    domain_path="/local/domain/"+str(vm.get_xid())
-    subprocess.check_call(["xenstore-write",
-        domain_path+"/qubes_ip",
-        vm.ip])
-    subprocess.check_call(["xenstore-write",
-        domain_path+"/qubes_gateway",
-        vm.netvm_vm.gateway])
-    subprocess.check_call(["xenstore-write",
-        domain_path+"/qubes_secondary_dns",
-        vm.netvm_vm.secondary_dns])
-    subprocess.check_call(["xl", "network-attach", vm.name, "ip="+vm.ip,
-        "backend="+vm.netvm_vm.name,
-        "script=/etc/xen/scripts/vif-route-qubes"])
+    # refresh IP, DNS etc
+    vm.create_xenstore_entries()
+    vm.attach_network(verbose = True)
 
 def set_updateable(vms, vm, args):
     if vm.is_updateable():