Java/Minecraft - 如何阅读/理解数据包

Question

我用 Java 编写了一个 Packet Sniffer，它运行良好，但现在我有一个带有整数的文本文件，但我不知道如何解码它们。 我已经尝试过使用这个：Minecraft Protocol，但我仍然无法解码数据包...

输出：

[Client] 15
[Client] 0
[Client] 47
[Client] 9
[Client] 108
[Client] 111
[Client] 99
[Client] 97
[Client] 108
[Client] 104
[Client] 111
[Client] 115
[Client] 116
[Client] 30
[Client] 97
[Client] 1
[Client] 1
[Client] 0


[Server] 118
[Server] 0
[Server] 116
[Server] 123
[Server] 34
[Server] 100
[Server] 101
[Server] 115
[Server] 99
[Server] 114
[Server] 105
[Server] 112
[Server] 116
[Server] 105
[Server] 111
[Server] 110
[Server] 34
[Server] 58
[Server] 34
[Server] 65
[Server] 32
[Server] 77
[Server] 105
[Server] 110
[Server] 101
[Server] 99
[Server] 114
[Server] 97
[Server] 102
[Server] 116
[Server] 32
[Server] 83
[Server] 101
[Server] 114
[Server] 118
[Server] 101
[Server] 114
[Server] 34
[Server] 44
[Server] 34
[Server] 112
[Server] 108
[Server] 97
[Server] 121
[Server] 101
[Server] 114
[Server] 115
[Server] 34
[Server] 58
[Server] 123
[Server] 34
[Server] 109
[Server] 97
[Server] 120
[Server] 34
[Server] 58
[Server] 50
[Server] 48
[Server] 44
[Server] 34
[Server] 111
[Server] 110
[Server] 108
[Server] 105
[Server] 110
[Server] 101
[Server] 34
[Server] 58
[Server] 48
[Server] 125
[Server] 44
[Server] 34
[Server] 118
[Server] 101
[Server] 114
[Server] 115
[Server] 105
[Server] 111
[Server] 110
[Server] 34
[Server] 58
[Server] 123
[Server] 34
[Server] 110
[Server] 97
[Server] 109
[Server] 101
[Server] 34
[Server] 58
[Server] 34
[Server] 83
[Server] 112
[Server] 105
[Server] 103
[Server] 111
[Server] 116
[Server] 32
[Server] 49
[Server] 46
[Server] 56
[Server] 46
[Server] 55
[Server] 34
[Server] 44
[Server] 34
[Server] 112
[Server] 114
[Server] 111
[Server] 116
[Server] 111
[Server] 99
[Server] 111
[Server] 108
[Server] 34
[Server] 58
[Server] 52
[Server] 55
[Server] 125
[Server] 125


[Client] 9
[Client] 1
[Client] 0
[Client] 0
[Client] 0
[Client] 0
[Client] 10
[Client] 158
[Client] 220
[Client] 203


[Server] 9
[Server] 1
[Server] 0
[Server] 0
[Server] 0
[Server] 0
[Server] 10
[Server] 158
[Server] 220
[Server] 203
[Server] -1


[Client] -1

如果有人有答案，我将不胜感激。

Answer 1

似乎没有整数大于 255，所以这是每行输出一个字节。您看到的数据包可能已压缩，但如果没有看到您的 Minecraft 用户/服务器的配置，就不可能说出来。如果它们实际上是压缩的 - 您需要先解压缩它们，然后才能对其进行分析。

为了帮助您进行解码，我强烈推荐 Wireshark。下载它并重新运行您的网络捕获。然后将解码后的输出与您的程序的输出进行比较。 Wireshark 会给出数据包中每个数据成员的含义。

编辑：您不清楚解码的哪一部分？在编程模式下使用纸笔和windows计算器，这里是第一个数据包的解码：

15 - Varint - length of the packet
0  - Varint - packet ID - Handshake
47 - VarInt - protocol version
     Following bytes are length prefixed server address in UTF-8:
9  - Lenght
108 - l
111 - o
99  - c
97  - a
108 - l
104 - h
111 - o
115 - s
116 - t
     Following 2 bytes are server port in unsigned short format (I guess 7777)
30
97

1  - Varint - Next state

我不清楚最后 2 个字节。

简而言之 - 对于每个数据包：

1. 查找数据包长度
2. 查找数据包类型
3. 使用数据包类型解码其余部分