Fix port number overflow (#2826)

python/sglang/srt/server_args.py

@@ -928,7 +928,10 @@ class PortArgs:
         while True:
             if is_port_available(port):
                 break
-            port += 42
+            if port < 60000:
+                port += 42
+            else:
+                port -= 43
 
         return PortArgs(
             tokenizer_ipc_name=tempfile.NamedTemporaryFile(delete=False).name,

python/sglang/srt/utils.py

@@ -335,6 +335,8 @@ def is_port_available(port):
             return True
         except socket.error:
             return False
+        except OverflowError:
+            return False
 
 
 def decode_video_base64(video_base64):