Open-source multiplayer game server compatible with the RuneScape client
https://www.openrs2.org/
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
85 lines
3.1 KiB
85 lines
3.1 KiB
# JS5 protocol
|
|
|
|
The JS5 remote protocol is used by the client to download groups of files from
|
|
the server as they are required, as well as prefetching certain groups in
|
|
advance. Groups contain the client's assets and scripts, and are stored in the
|
|
cache.
|
|
|
|
## Upstream
|
|
|
|
| Opcode | Description |
|
|
|-------:|--------------------------|
|
|
| 0 | Request group (prefetch) |
|
|
| 1 | Request group (urgent) |
|
|
| 2 | Logged in |
|
|
| 3 | Logged out |
|
|
| 4 | Rekey |
|
|
| 6 | Connected |
|
|
| 7 | Disconnect |
|
|
|
|
All upstream packets are exactly 4 bytes long, including the opcode. Unused
|
|
payload bytes are set to zero.
|
|
|
|
### Request group (prefetch/urgent)
|
|
|
|
| Data type | Description |
|
|
|---------------|-------------|
|
|
| UnsignedByte | Archive ID |
|
|
| UnsignedShort | Group ID |
|
|
|
|
Requests a group. Urgent requests have a higher priority than prefetch requests,
|
|
as the client needs the group immediately. Prefetch requests are used to
|
|
prepopulate most of the cache in the background.
|
|
|
|
### Rekey
|
|
|
|
| Data type | Description |
|
|
|---------------|----------------------|
|
|
| UnsignedByte | Key |
|
|
| UnsignedShort | Unused (set to zero) |
|
|
|
|
Sent to set the encryption key.
|
|
|
|
### Logged in/out
|
|
|
|
Sent whenever the player logs in or out of the game. Consensus in the community
|
|
is that the logged in/out state is probably used for prioritisation, much like
|
|
the distinction between prefetch/urgent requests.
|
|
|
|
### Connected
|
|
|
|
| Data type | Description |
|
|
|----------------|-----------------------------|
|
|
| UnsignedMedium | Unknown (always set to `3`) |
|
|
|
|
Sent immediately after the JS5 connection is established. Its purpose is not
|
|
known.
|
|
|
|
### Disconnect
|
|
|
|
Requests that the server closes the connection. Sent by the `::serverjs5drop`
|
|
command.
|
|
|
|
## Downstream
|
|
|
|
There is only a single type of response packet, and as such, there are no
|
|
response opcodes. The packet contains a group requested by the client.
|
|
|
|
| Data type | Description |
|
|
|----------------|-----------------------------------------------------------|
|
|
| UnsignedByte | Archive ID |
|
|
| UnsignedShort | Group ID |
|
|
| UnsignedByte | Compression type (ORed with `0x80` for prefetch requests) |
|
|
| Int | Compressed length |
|
|
| Int (optional) | Uncompressed length (present iff the group is compressed) |
|
|
| Byte[] | Compressed data (with `0xFF` markers, see below) |
|
|
|
|
If encryption is enabled, all downstream bytes are XORed with the encryption
|
|
key. The client enables encryption if the checksum of a group does not match the
|
|
expected checksum in the master index or index.
|
|
|
|
The encryption scheme is probably used to defend against middle boxes tampering
|
|
with the plaintext traffic.
|
|
|
|
After the first 512 bytes of a response (including the header), every subsequent
|
|
block of 511 bytes is prefixed with a single `0xFF` byte.
|
|
|