Node js peerwire 协议实现

Posted 2023-02-23

【中文标题】Node js peerwire 协议实现

【英文标题】：Node js peerwire protocol implementation

【发布时间】：2019-02-19 15:36:59

【问题描述】：

在实现 Bittorrent 协议时，要与对等点通信并获取片段，一些传入的对等点消息会出现问题： 此类消息的缓冲区包含大约 200 个“255”值，然后是大约 200 个随机数。问题是我在此类有效负载的规范定义中找不到。缓冲区中第一个或第四个字节描述的消息类型，在我的情况下它们都等于255，并且没有这种类型的消息（可用类型有：1-8、16、21-23）

缓冲区的数组表示：

[255,255,255,255,255,239,254,255,255,255,255,255,255,255,255,247,255,255,255,255,255,255,255,255,255,255,223,255,255,255,255,255,255,255,255,255,255,255,255,255,254,255,255,255,239,255,254,237,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,239,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,251,255,255,255,255,255,255,255,255,255,255,255,255,253,191,255,255,255,255,255,255,253,255,255,255,255,255,255,255,255,255,255,255,249,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,247,255,255,255,255,255,255,255,254,191,255,127,255,247,255,255,255,255,255,255,255,255,255,255,255,255,255,0,0,0,5,4,0,0,3,11,0,0,0,5,4,0,0,5,196,0,0,0,5,4,0,0,1,186,0,0,0,5,4,0,0,2,102,0,0,0,5,4,0,0,2,95,0,0,0,5,4,0,0,6,7,0,0,0,5,4,0,0,4,30,0,0,0,5,4,0,0,4,190,0,0,0,5,4,0,0,4,189,0,0,0,5,4,0,0,2,47,0,0,0,5,4,0,0,1,19,0,0,0,5,4,0,0,0,28,0,0,0,5,4,0,0,0,223,0,0,0,5,4,0,0,2,75,0,0,0,5,4,0,0,4,33,0,0,0,5,4,0,0,1,31,0,0,0,5,4,0,0,1,100,0,0,0,5,4,0,0,6,24,0,0,0,5,4,0,0,3,181,0,0,0,5,4,0,0,4,94,0,0,0,5,4,0,0,2,99,0,0,0,5,4,0,0,6,44,0,0,0,5,4,0,0,0,74,0,0,0,5,4,0,0,6,9,0,0,0,1,1]

【参考方案1】：

你所拥有的是一个 bitfield 消息，缺少开头的长度、类型和可能的一些数据，24 个 have 消息和一个 uncoke 消息。

255,255,255,255,255,239,254,255,255,255,255,255,255,255,255,247,255,255,255,255,255,255,255,255,255,255,223,255,255,255,255,255,255,255,255,255,255,255,255,255,254,255,255,255,239,255,254,237,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,239,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,251,255,255,255,255,255,255,255,255,255,255,255,255,253,191,255,255,255,255,255,255,253,255,255,255,255,255,255,255,255,255,255,255,249,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,247,255,255,255,255,255,255,255,254,191,255,127,255,247,255,255,255,255,255,255,255,255,255,255,255,255,255,
0,0,0,5,4,0,0,3,11,
0,0,0,5,4,0,0,5,196,
0,0,0,5,4,0,0,1,186,
0,0,0,5,4,0,0,2,102,
0,0,0,5,4,0,0,2,95,
0,0,0,5,4,0,0,6,7,
0,0,0,5,4,0,0,4,30,
0,0,0,5,4,0,0,4,190,
0,0,0,5,4,0,0,4,189,
0,0,0,5,4,0,0,2,47,
0,0,0,5,4,0,0,1,19,
0,0,0,5,4,0,0,0,28,
0,0,0,5,4,0,0,0,223,
0,0,0,5,4,0,0,2,75,
0,0,0,5,4,0,0,4,33,
0,0,0,5,4,0,0,1,31,
0,0,0,5,4,0,0,1,100,
0,0,0,5,4,0,0,6,24,
0,0,0,5,4,0,0,3,181,
0,0,0,5,4,0,0,4,94,
0,0,0,5,4,0,0,2,99,
0,0,0,5,4,0,0,6,44,
0,0,0,5,4,0,0,0,74,
0,0,0,5,4,0,0,6,9,
0,0,0,1,1

BitTorrent 点对点连接由两个单向字节流组成，每个方向一个。从接收缓冲区读取数据流时，不要期望每次只获得一条完整的消息。您必须自己将流拆分为消息。此外，请准备好响应的对等方可能会在 握手 结束后立即开始发送消息。

【讨论】：

谢谢，这很有帮助，我认为我应该为对等消息使用某种缓冲区，目前我正在将每条传入消息作为单独的消息解析