From 70cc0d1d9acbc2fbbca155db8a2fc9510a910705 Mon Sep 17 00:00:00 2001 From: Graham Date: Sun, 20 Dec 2020 21:52:11 +0000 Subject: [PATCH] Add JAGGRAB documentation Signed-off-by: Graham --- share/doc/protocol/jaggrab.md | 58 +++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 share/doc/protocol/jaggrab.md diff --git a/share/doc/protocol/jaggrab.md b/share/doc/protocol/jaggrab.md new file mode 100644 index 0000000000..7080721cbe --- /dev/null +++ b/share/doc/protocol/jaggrab.md @@ -0,0 +1,58 @@ +# JAGGRAB protocol + +JAGGRAB is a very simple protocol used by the loader to fetch the game's code. +It is only used as a fallback if fetching the code via HTTP fails. It is very +similar to [HTTP/0.9][http09] - the first version of HTTP. + +The loader opens a connection to the secondary game server port (443) and sends +the 'switch to JAGGRAB mode' packet. As this packet has no payload, it only +contains a single opcode byte: `17`. + +The loader then writes the following string: + + JAGGRAB / + +where `` is replaced with the name of the file to fetch. The string +is followed by two line feed characters. + +The server responds with the requested file and then closes the connection. + +The file names are suffixed with their CRC-32 checksum (for example, +`unpackclass.pack` -> `unpackclass_-1911426584.pack`). The same file names are +used when the client requests the files over HTTP, so the suffixes are +presumably for cache busting. The Old School RuneScape servers do not require +the checksum suffix to be present or correct. + +In build 550, the following files may be requested with JAGGRAB: + +| Remote file name | Local file name | Description | +|------------------------|------------------------|----------------------------------------------------| +| `unpackclass.pack` | `game_unpacker.dat` | packclass unpacker | +| `runescape.pack200` | `main_file_cache.dat0` | SD client (pack200 format) | +| `runescape.js5` | `main_file_cache.dat1` | SD client (packclass format) | +| `runescape_gl.pack200` | `main_file_cache.dat3` | HD client (pack200 format) | +| `runescape_gl.js5` | `main_file_cache.dat4` | HD client (packclass format) | +| `jaggl.pack200` | `main_file_cache.dat5` | OpenGL bindings (pack200 format) | +| `jaggl.js5` | `main_file_cache.dat6` | OpenGL bindings (packclass format) | +| `jaggl_0_0.lib` | `jaggl.dll` | OpenGL native library (Windows i386) | +| `jaggl_1_0.lib` | `libjaggl.so` | OpenGL native library (Linux i386) | +| `jaggl_1_1.lib` | `libjaggl_dri.so` | DRI hack native library (Linux i386) | +| `jaggl_2_0.lib` | `libjaggl.jnilib` | OpenGL native library (macOS PowerPC) | +| `jaggl_3_0.lib` | `libjaggl.jnilib` | OpenGL native library (macOS i386) | +| `jaggl_4_0.lib` | `jaggl.dll` | OpenGL native library (Windows amd64) | +| `jagmisc_0.lib` | `jagmisc.dll` | Miscellaneous native library (Windows i386) | +| `jagmisc_1.lib` | `jagmiscms.dll` | Miscellaneous native library (Windows i386, MSJVM) | +| `jagmisc_2.lib` | `jagmisc64.dll` | Miscellaneous native library (Windows amd64) | + +Note that OpenRS2's client patcher changes the list of supported platforms: + +* MSJVM support is removed. +* PowerPC support is removed. +* amd64 support is added to macOS and Linux. + +This causes some differences to the list of supported files. + +It also normalises some of the local file names (for example, `jagmisc64.dll` -> +`jagmisc.dll`, `libjaggl.jnilib` -> `libjaggl.dylib`). + +[http09]: https://www.w3.org/Protocols/HTTP/AsImplemented.html