Handle the SWITCH_DC RPCError by changing the data center and creating a new mtproto_connection

mtproto-client.c

@@ -1751,6 +1751,10 @@ int rpc_execute (struct connection *c, int op, int len) {
   case st_authorized:
     if (op < 0 && op >= -999) {
       logprintf ("Server error %d\n", op);
+      char code[12] = {0};
+      snprintf (code, 12, "%d", op);
+      c->mtconnection->c_state = st_error;
+      telegram_change_state (instance, STATE_ERROR, code);
     } else {
       process_rpc_message (c, (void *)(Response/* + 8*/), Response_len/* - 12*/);
     }

queries.c

@@ -583,8 +583,10 @@ int check_phone_on_error (struct query *q UU, int error_code, int l, char *error
     //check_phone_result = 1;
   } else {
     logprintf ( "error_code = %d, error = %.*s\n", error_code, l, error);
+    telegram_change_state(instance, STATE_ERROR, error);
   }
-  telegram_change_state(instance, STATE_DISCONNECTED_SWITCH_DC, error);
+  telegram_change_state(instance,
+    STATE_DISCONNECTED_SWITCH_DC, &instance->auth.dc_working_num);
   return 0;
 }
 

telegram.c

@@ -73,6 +73,9 @@ void on_state_change(struct telegram *instance, int state, void *data)
                 err = "<no description>";
             }
             logprintf("telegram errored: %s\n", err);
+
+            // close the connection
+            mtproto_close (instance->connection);
         }
         break;
 
@@ -108,9 +111,26 @@ void on_state_change(struct telegram *instance, int state, void *data)
             // wait for user input ...
         break;
 
-        case STATE_DISCONNECTED_SWITCH_DC:
-            logprintf("Have to migrate to other DC");
-            instance->connection
+        case STATE_DISCONNECTED_SWITCH_DC: {
+            // telegram demands that we use a different data center, which caused
+            // the current mtproto_connection to be disconnected
+            
+            int target_dc = *(int*) data;
+            logprintf ("Disconnected: Migrate to data center %d\n", target_dc);
+
+            // close old connection and mark it for destruction
+            mtproto_close (instance->connection);
+            if (instance->proxy_request_cb) {
+                // tell the proxy to close all connections
+                instance->proxy_close_cb (instance, 
+                    instance->connection->connection->fd);
+            }
+            
+            // start a new connection to the demanded data center. The pointer to the
+            // currently working dc should have already been updated by the 
+            // on_error function of the query
+            telegram_network_connect (instance);
+        }
         break;
     }
 }