rina: recover from cases where normal.DIF is already registered at startup

Which happens when only re6stnet is restarted. The DIF must even be recreated
if the local certificate has changed, so that we can reconfigure the shim DIF.

re6st/rina.py

@@ -111,6 +111,7 @@ class Shim(object):
     def __init__(self, ipcp_id, dif):
         self.ipcp_id = ipcp_id
         self.dif = dif
+        self._asking_info = {}
         self._enabled = weakref.WeakValueDictionary()
 
     def _kernel(self, **kw):
@@ -131,7 +132,7 @@ class Shim(object):
                 len(ap), ap, len(ip), ip, len(port), port))
         self._enabled[prefix] = tm._getPeer(prefix)
 
-    def update(self, tm):
+    def init(self, tm):
         global resolve_thread
         if resolve_thread is None:
             s = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
@@ -142,8 +143,10 @@ class Shim(object):
             resolve_thread.start()
         prefix = tm._prefix
         self._enabled[prefix] = tm.cert
-        self._asking_info = {prefix: float('inf')}
-        def update(tm):
+        self._asking_info[prefix] = float('inf')
+
+    def update(self, tm):
+        enabled = self._enabled
         ap = ap_name(tm._prefix)
         name = ap + "-1--"
         step = 0 # do never retry immediately
@@ -151,30 +154,38 @@ class Shim(object):
             normal_id = None
             for ipcp in ipcm.iterIpcp():
                 if ipcp[0] == self.ipcp_id:
-                        registered = name in ipcp[4]
+                    registered = ipcp[4]
                 elif ipcp[1] == name:
                     normal_id = ipcp[0]
                     normal_status = ipcp[3]
-                if registered:
+                elif ipcp[1] in registered:
+                    if step or not ipcm("destroy-ipcp", ipcp[0]):
+                        return
+                    step = 1
+            if name in registered:
                 break
             if normal_id is None:
-                    if step or not ipcm("create-ipcp", ap, 1, "normal-ipc"):
+                if step > 1 or not ipcm("create-ipcp", ap, 1, "normal-ipc"):
                     return
-                    step = 1
+                step = 2
             elif normal_status == "INITIALIZED":
-                    if step > 1 or not ipcm("assign-to-dif", normal_id,
+                if step > 2 or not ipcm("assign-to-dif", normal_id,
                                         NORMAL_DIF, DEFAULT_DIF):
                     return
-                    step = 2
+                step = 3
             elif normal_status.startswith("ASSIGNED TO DIF"):
-                    if step > 2 or not ipcm("register-at-dif",
-                                            normal_id, self.dif):
+                enabled.clear()
+                self.init(tm)
+                port = str(PORT)
+                self._kernel(
+                    hostname=utils.ipFromBin(tm._network + tm._prefix, '1'),
+                    expReg="1:%s:%s0:%s:%s" % (len(ap), ap, len(port), port))
+                if step > 3 or not ipcm("register-at-dif", normal_id, self.dif):
                     return
-                    step = 3
+                step = 4
             else:
                 return
         asking_info = self._asking_info
-            enabled = self._enabled
         enrolled = set(ap_prefix(neigh[0].split('-', 1)[0])
             for neigh in ipcm.iterNeigh(normal_id))
         now = time.time()
@@ -194,28 +205,17 @@ class Shim(object):
                         # so don't block for too long.
                         if now + 1 < time.time():
                             return
-                        continue
-                    if asking_info.get(prefix, 0) < now and tm.askInfo(prefix):
+                elif asking_info.get(prefix, 0) < now and tm.askInfo(prefix):
                     self._enroll(tm, prefix)
-                        self._asking_info[prefix] = now + 60
-        ap = ap_name(prefix)
-        port = str(PORT)
-        self._kernel(hostname=utils.ipFromBin(tm._network + prefix, '1'),
-            expReg="1:%s:%s0:%s:%s" % (len(ap), ap, len(port), port))
-        self.update = update
-        update(tm)
+                    asking_info[prefix] = now + 60
 
     def enabled(self, tm, prefix, enroll):
         logging.debug("RINA: enabled(%s, %s)", prefix, enroll)
-        try:
-            asking_info = self._asking_info
-        except AttributeError:
-            return
         if enroll:
-            asking_info.pop(prefix, None)
+            self._asking_info.pop(prefix, None)
             self._enroll(tm, prefix)
         else:
-            asking_info[prefix] = float('inf')
+            self._asking_info[prefix] = float('inf')
 
     @staticmethod
     def _resolve(sock):
@@ -287,9 +287,9 @@ if os.path.isdir("/sys/rina"):
                     return False
                 dif = sysfs_read(ipcp + "/dif")
                 if dif.endswith("///"):
-                    host_name = sysfs_read(ipcp + "/host_name")
-                    if not host_name:
+                    if shim is None:
                         shim = Shim(int(ipcp.rsplit("/", 1)[1]), dif[:-3])
+                        shim.init(tunnel_manager)
                     if route_dumped:
                         shim.update(tunnel_manager)
                     return True