bittorrent - 如何从 DHT 中提取 torrent 文件？

Question

我编写了一个简单的脚本，可以找出给定 info_hash 的示例对等 IP。我在 BEP-0005 中看不到此类信息：我如何实际从 DHT 中提取 torrent 文件？

Answer 1

DHT 不提供种子文件。它只是为各个信息散列提供对等列表。Torrent 文件，或者更确切地说是不可变的信息字典，由 bittorrent 群本身提供。

您必须部分实现BEP3、BEP10，最后是 BEP9才能执行元数据交换。此外，实施BEP29和BEP11可以提供改进的连接性，这在检索小群上的元数据时很有用

其次，在不提供任何请求的情况下消耗 DHT 的资源，或反复锤击节点（尤其是引导节点）被认为是不礼貌的。如果您打算获得大量的 torrent 文件，您应该运行一个 DHT 节点作为守护进程，例如通过 Juliusz Chroboczek 的dht lib (C) 或我的(java)。我的实现还包含一个元数据检索服务。libtorrent还应该提供所有必要的部分来实现相同的目标。

Answer 2

这是一个 base64 编码的 .pcap 文件，显示了实践中的完整通信（注意最后一个数据包）。对其进行解码并在 Wireshark 中打开将向您展示整个过程 - 结合 8472 答案中列出的 BEP，这可以作为示例。

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