bittorrent - DHT中announce_peer的token

Question

在http://www.bittorrent.org/beps/bep_0005.html ，announce_peer 查询需要一个 token ，该 token 具有 require，“响应先前的 get_peers 查询而收到的“ token ””。

这是否意味着如果节点 A 从未向节点 B 发送 get_peer 查询，那么节点 A 将永远不会收到来自节点 B 的 peer_announce 查询？

Answer 1

Does it mean that if node A has never send a get_peer query to node B, then node A would never receive a peer_announce query from node B ?

不对，恰恰相反:

• 节点 A 想要宣布它正在下载某个 torrent。
• 节点 A 向节点 B 发出 get_peers 查询。
• 节点 B 向节点 A 发送对它刚刚发送的 get_peers 查询的响应。节点 B 的响应包括 token。
• 现在，节点 A 可以使用刚刚从节点 B 的响应中收到的 token 向节点 B 发送一个 announce_peer 查询。

为什么这么大惊小怪？

The return value for a query for peers includes an opaque value known as the "token." For a node to announce that its controlling peer is downloading a torrent, it must present the token received from the same queried node in a recent query for peers. When a node attempts to "announce" a torrent, the queried node checks the token against the querying node's IP address. This is to prevent malicious hosts from signing up other hosts for torrents.

http://www.bittorrent.org/beps/bep_0005.html