show CIDR error more friendly

shadowsocks/common.py

@@ -206,7 +206,7 @@ class IPNetwork(object):
             hi, lo = struct.unpack("!QQ", inet_pton(addr_family, block[0]))
             ip = (hi << 64) | lo
         else:
-            raise SyntaxError("Not a valid CIDR notation: %s" % addr)
+            raise Exception("Not a valid CIDR notation: %s" % addr)
         if len(block) is 1:
             prefix_size = 0
             while (ip & 1) == 0 and ip is not 0:
@@ -218,7 +218,7 @@ class IPNetwork(object):
             prefix_size = addr_len - int(block[1])
             ip >>= prefix_size
         else:
-            raise SyntaxError("Not a valid CIDR notation: %s" % addr)
+            raise Exception("Not a valid CIDR notation: %s" % addr)
         if addr_family is socket.AF_INET:
             self._network_list_v4.append((ip, prefix_size))
         else:

shadowsocks/utils.py

@@ -193,8 +193,12 @@ def get_config(is_local):
             sys.exit(2)
     else:
         config['server'] = config.get('server', '0.0.0.0')
-        config['forbidden_ip'] = \
+        try:
-            IPNetwork(config.get('forbidden_ip', '127.0.0.0/8,::1/128'))
+            config['forbidden_ip'] = \
+                IPNetwork(config.get('forbidden_ip', '127.0.0.0/8,::1/128'))
+        except Exception as e:
+            logging.error(e)
+            sys.exit(2)
     config['server_port'] = config.get('server_port', 8388)
 
     if is_local and not config.get('password', None):