From 0cd02fd2da18ad381d8954c9657849f4007caa2d Mon Sep 17 00:00:00 2001
From: iceiix <43691553+iceiix@users.noreply.github.com>
Date: Sat, 11 May 2019 18:37:33 -0700
Subject: [PATCH] Forge 1.8.9-1.12.2 handshake protocol support (#144)

Adds support for connecting to Forge servers from 1.8.9 up to 1.12.2.
(1.7.10 was already supported with #134 #88)

Tested on:

- 1.8.9 + forge 11.15.1.2318 + ironchest
- 1.10.2 + forge 12.18.3.2511 + ironchest
- 1.11.2 + forge 13.20.1.2588 + ironchest
- 1.12.2 + forge 14.23.5.2837 + ironchest

Changes:

* Parse and handle FmlHs::RegistryData packet for 1.8+

* Fix RegistryData acknowledgement phase WaitingServerComplete

* Fix acknowledgement phase for 1.7.10 ModIdData too, somehow it worked accidentally

* Append \0FML\0 to end of server hostname if Forge mods detected

https://wiki.vg/Minecraft_Forge_Handshake#Connection_to_a_forge_server
---
 src/protocol/forge.rs | 24 +++++++++++++++++-------
 src/server/mod.rs     | 14 ++++++++++++--
 2 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/src/protocol/forge.rs b/src/protocol/forge.rs
index 21d47b3..841df92 100644
--- a/src/protocol/forge.rs
+++ b/src/protocol/forge.rs
@@ -97,7 +97,6 @@ pub enum FmlHs {
     ModList {
         mods: LenPrefixed<VarInt, ForgeMod>,
     },
-    /* TODO: 1.8+ https://wiki.vg/Minecraft_Forge_Handshake#Differences_from_Forge_1.7.10
     RegistryData {
         has_more: bool,
         name: String,
@@ -105,7 +104,6 @@ pub enum FmlHs {
         substitutions: LenPrefixed<VarInt, String>,
         dummies: LenPrefixed<VarInt, String>,
     },
-    */
     ModIdData {
         mappings: LenPrefixed<VarInt, ModIdMapping>,
         block_substitutions: LenPrefixed<VarInt, String>,
@@ -145,11 +143,23 @@ impl Serializable for FmlHs {
                 })
             },
             3 => {
-                Ok(FmlHs::ModIdData {
-                    mappings: Serializable::read_from(buf)?,
-                    block_substitutions: Serializable::read_from(buf)?,
-                    item_substitutions: Serializable::read_from(buf)?, 
-                })
+                let protocol_version = unsafe { crate::protocol::CURRENT_PROTOCOL_VERSION };
+
+                if protocol_version >= 47 {
+                    Ok(FmlHs::RegistryData {
+                        has_more: Serializable::read_from(buf)?,
+                        name: Serializable::read_from(buf)?,
+                        ids: Serializable::read_from(buf)?,
+                        substitutions: Serializable::read_from(buf)?,
+                        dummies: Serializable::read_from(buf)?,
+                    })
+                } else {
+                    Ok(FmlHs::ModIdData {
+                        mappings: Serializable::read_from(buf)?,
+                        block_substitutions: Serializable::read_from(buf)?,
+                        item_substitutions: Serializable::read_from(buf)?, 
+                    })
+                }
             },
             255 => {
                 Ok(FmlHs::HandshakeAck {
diff --git a/src/server/mod.rs b/src/server/mod.rs
index c2f0a55..9be139a 100644
--- a/src/server/mod.rs
+++ b/src/server/mod.rs
@@ -108,7 +108,8 @@ impl Server {
     pub fn connect(resources: Arc<RwLock<resources::Manager>>, profile: mojang::Profile, address: &str, protocol_version: i32, forge_mods: Vec<forge::ForgeMod>) -> Result<Server, protocol::Error> {
         let mut conn = protocol::Conn::new(address, protocol_version)?;
 
-        let host = conn.host.clone();
+        let tag = if forge_mods.len() != 0 { "\0FML\0" } else { "" };
+        let host = conn.host.clone() + tag;
         let port = conn.port;
         conn.write_packet(protocol::packet::handshake::serverbound::Handshake {
              protocol_version: protocol::VarInt(protocol_version),
@@ -711,7 +712,16 @@ impl Server {
                         self.write_fmlhs_plugin_message(&HandshakeAck { phase: WaitingServerData });
                     },
                     ModIdData { mappings: _, block_substitutions: _, item_substitutions: _ } => {
-                        self.write_fmlhs_plugin_message(&HandshakeAck { phase: WaitingServerData });
+                        println!("Received FML|HS ModIdData");
+                        self.write_fmlhs_plugin_message(&HandshakeAck { phase: WaitingServerComplete });
+                        // TODO: dynamically register mod blocks
+                    },
+                    RegistryData { has_more, name, ids: _, substitutions: _, dummies: _ } => {
+                        println!("Received FML|HS RegistryData for {}", name);
+                        if !has_more {
+                            self.write_fmlhs_plugin_message(&HandshakeAck { phase: WaitingServerComplete });
+                        }
+                        // TODO: dynamically register mod blocks
                     },
                     HandshakeAck { phase } => {
                         match phase {