fix auto-connect: do not use a random interface

lib/network.py

@@ -227,9 +227,7 @@ class Network(util.DaemonThread):
         self.banner = ''
         self.donation_address = ''
         self.relay_fee = None
-        self.heights = {}
-        self.merkle_roots = {}
-        self.utxo_roots = {}
+        self.headers = {}
         # callbacks passed with subscriptions
         self.subscriptions = defaultdict(list)
         self.sub_cache = {}
@@ -297,7 +295,8 @@ class Network(util.DaemonThread):
             pass
 
     def get_server_height(self):
-        return self.heights.get(self.default_server, 0)
+        h = self.headers.get(self.default_server)
+        return h['block_height'] if h else 0
 
     def server_is_lagging(self):
         sh = self.get_server_height()
@@ -494,7 +493,12 @@ class Network(util.DaemonThread):
             if suggestion and self.protocol == deserialize_server(suggestion)[2]:
                 self.switch_to_interface(suggestion)
             else:
-                self.switch_to_random_interface()
+                # switch to one that has the correct header (not height)
+                header = self.get_header(self.get_local_height())
+                filtered = map(lambda x:x[0], filter(lambda x: x[1]==header, self.headers.items()))
+                if filtered:
+                    choice = random.choice(filtered)
+                    self.switch_to_interface(choice)
 
     def switch_to_interface(self, server):
         '''Switch to server as our interface.  If no connection exists nor
@@ -676,7 +680,7 @@ class Network(util.DaemonThread):
             self.set_status('disconnected')
         if server in self.interfaces:
             self.close_interface(self.interfaces[server])
-            self.heights.pop(server, None)
+            self.headers.pop(server, None)
             self.notify('interfaces')
 
     def new_interface(self, server, socket):
@@ -857,9 +861,7 @@ class Network(util.DaemonThread):
         height = header.get('block_height')
         if not height:
             return
-        self.heights[i.server] = height
-        self.merkle_roots[i.server] = header.get('merkle_root')
-        self.utxo_roots[i.server] = header.get('utxo_root')
+        self.headers[i.server] = header
 
         # Queue this interface's height for asynchronous catch-up
         self.bc_requests.append((i, {'if_height': height}))