tcp 中fsm简化版的编写

最新推荐文章于 2023-12-12 20:45:00 发布

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本文介绍了一种使用JavaScript实现的TCP状态机模型。该模型通过数组形式定义了从初始状态到目标状态的所有转换，并通过遍历事件列表来更新状态。文章提供了一个具体的实现案例，包括状态转移逻辑和错误处理。

fsm 是当前状态+输入=末状态

参数表
Format is INITIAL_STATE: EVENT -> NEW_STATE
CLOSED: APP_PASSIVE_OPEN -> LISTEN

CLOSED: APP_ACTIVE_OPEN -> SYN_SENT

LISTEN: RCV_SYN -> SYN_RCVD

LISTEN: APP_SEND -> SYN_SENT

LISTEN: APP_CLOSE -> CLOSED

SYN_RCVD: APP_CLOSE -> FIN_WAIT_1

SYN_RCVD: RCV_ACK -> ESTABLISHED

SYN_SENT: RCV_SYN -> SYN_RCVD

SYN_SENT: RCV_SYN_ACK -> ESTABLISHED

SYN_SENT: APP_CLOSE -> CLOSED

ESTABLISHED: APP_CLOSE -> FIN_WAIT_1

ESTABLISHED: RCV_FIN -> CLOSE_WAIT

FIN_WAIT_1: RCV_FIN -> CLOSING

FIN_WAIT_1: RCV_FIN_ACK -> TIME_WAIT

FIN_WAIT_1: RCV_ACK -> FIN_WAIT_2

CLOSING: RCV_ACK -> TIME_WAIT

FIN_WAIT_2: RCV_FIN -> TIME_WAIT

TIME_WAIT: APP_TIMEOUT -> CLOSED

CLOSE_WAIT: APP_CLOSE -> LAST_ACK

LAST_ACK: RCV_ACK -> CLOSED

我的处理方案当前状态+输入=末状态 2个状态一个输入恰好可以构成一个字符串用|连接，刚好组成一个数组，再遍历数组各个元素搜索状态，搜索输入若匹配则将第3个赋予state
代码如下：

var FSMData=[//构建数组
'CLOSED | APP_PASSIVE_OPEN | LISTEN',

'CLOSED | APP_ACTIVE_OPEN |SYN_SENT',

'LISTEN| RCV_SYN         | SYN_RCVD',

'LISTEN| APP_SEND        | SYN_SENT',

'LISTEN| APP_CLOSE        | CLOSED',

'SYN_RCVD| APP_CLOSE      | FIN_WAIT_1',

'SYN_RCVD| RCV_ACK        | ESTABLISHED',

'SYN_SENT| RCV_SYN        | SYN_RCVD',

'SYN_SENT| RCV_SYN_ACK    | ESTABLISHED',

'SYN_SENT| APP_CLOSE      | CLOSED',

'ESTABLISHED| APP_CLOSE | FIN_WAIT_1',

'ESTABLISHED| RCV_FIN   | CLOSE_WAIT',

'FIN_WAIT_1| RCV_FIN     | CLOSING',

'FIN_WAIT_1| RCV_FIN_ACK | TIME_WAIT',

'FIN_WAIT_1| RCV_ACK     | FIN_WAIT_2',

'CLOSING| RCV_ACK | TIME_WAIT',

'FIN_WAIT_2|RCV_FIN | TIME_WAIT',

'TIME_WAIT|APP_TIMEOUT | CLOSED',

'CLOSE_WAIT| APP_CLOSE | LAST_ACK',

'LAST_ACK| RCV_ACK | CLOSED']

function traverseTCPStates(eventList){
  var state = "CLOSED";  // initial state, always
  for(var i=0;i<eventList.length;i++)
	{

		if(! judge (eventList[i]) )  return state;
//若返回false，不再进行，返回
	}
  return state;//最终返回


  function judge(_eventListPara){
//判断该输入是否有匹配，有的话更改state，返回//true，无返回false  更改state为error



	for(var j=0; j<FSMData.length; j++)
		{
		FSMData [j]=FSMData [j].replace(/\s+/g,'');//去空格因为数组不会自动去空格
		var arr=FSMData [j].split("|");//剥离三个东东
		if(arr[0]==state && arr[1]==_eventListPara) 
			{
				 state= arr[2];

				 return true;
			}
		}

		state ='ERROR';
		return false;

	}
}