status-im/eth2.0-specs
2
0
Fork 0
mirror of https://github.com/status-im/eth2.0-specs.git synced 2025-02-26 01:05:15 +00:00
Code Issues Projects Releases Wiki Activity

fix message-id issues

Browse Source
This commit is contained in:
Danny Ryan 2020-10-06 14:42:23 -06:00
parent 29b5efd63e
commit a365fcb03b
No known key found for this signature in database
GPG Key ID: 2765A792E42CE07A
1 changed files with 14 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
specs/phase0/p2p-interface.md
View File

@ -243,11 +243,21 @@ Each gossipsub [message](https://github.com/libp2p/go-libp2p-pubsub/blob/master/
Clients MUST reject (fail validation) messages that are over this size limit. Clients MUST reject (fail validation) messages that are over this size limit.
Likewise, clients MUST NOT emit or propagate messages larger than this limit. Likewise, clients MUST NOT emit or propagate messages larger than this limit.
The `message-id` of a gossipsub message MUST be the first 8 bytes of the SHA-256 hash of the message data, i.e.: The `message-id` of a gossipsub message MUST be the following 20 byte value computed from the message data:
* If `message.data` can be snappy decompressed:
* Let `message-id` be the first 20 bytes of the `SHA256` hash of the snappy decompressed message data,
i.e. `SHA256(snappy_decompress(message.data))[:20]`.
* Then set the most significant bit of the left-most byte of `message-id` to 1,
i.e. `message-id[0] |= (0x01 << 7)`.
* Otherwise:
* Let `message-id` be the first 20 bytes of the `SHA256` hash of the raw message data,
i.e. `SHA256(message.data)[:20]`.
* Then set the most significant bit of the left-most byte of `message-id` to 0,
i.e. `message-id[0] &= (0xFF >> 1)`.
```python *Note*: The above logic handles two exceptional cases:
message-id: SHA256(message.data)[0:8] (1) multiple snappy `data` can decompress to the same value,
``` and (2) some message `data` can fail to snappy decompress altogether.
The payload is carried in the `data` field of a gossipsub message, and varies depending on the topic: The payload is carried in the `data` field of a gossipsub message, and varies depending on the topic: