Add Packet compression

README.md

@@ -33,7 +33,7 @@ Pumpkin is currently under heavy development.
 - Login
   - [x] Authentication
   - [x] Encryption
-  - [ ] Packet Compression
+  - [x] Packet Compression
 - Player Configuration
   - [x] Registries (biome types, paintings, dimensions)
   - [x] Server Brand

pumpkin-protocol/Cargo.toml

@@ -15,6 +15,8 @@ serde = { version = "1.0", features = ["derive"] }
 # to parse strings to json responses
 serde_json = "1.0"
 
+flate2 = "1.0.30"
+
 thiserror = "1.0.63"
 log = "0.4"
 num-traits = "0.2"

pumpkin-protocol/src/lib.rs

@@ -145,8 +145,16 @@ pub enum PacketError {
     DecodeID,
     #[error("failed to encode packet ID")]
     EncodeID,
+    #[error("failed to encode packet Length")]
+    EncodeLength,
+    #[error("failed to encode packet data")]
+    EncodeData,
     #[error("failed to write encoded packet")]
     EncodeFailedWrite,
+    #[error("failed to write into decoder")]
+    FailedWrite,
+    #[error("failed to flush decoder")]
+    FailedFinish,
     #[error("failed to write encoded packet to connection")]
     ConnectionWrite,
     #[error("packet exceeds maximum length")]

pumpkin-protocol/src/packet_decoder.rs

@@ -1,6 +1,11 @@
 use aes::cipher::{generic_array::GenericArray, BlockDecryptMut, BlockSizeUser, KeyIvInit};
 use bytes::{Buf, BytesMut};
 
+use std::io::Write;
+
+use bytes::BufMut;
+use flate2::write::ZlibDecoder;
+
 use crate::{
     bytebuf::ByteBuffer, PacketError, RawPacket, VarInt, VarIntDecodeError, MAX_PACKET_SIZE,
 };
@@ -11,7 +16,8 @@ type Cipher = cfb8::Decryptor<aes::Aes128>;
 #[derive(Default)]
 pub struct PacketDecoder {
     buf: BytesMut,
-
+    decompress_buf: BytesMut,
+    compression: Option<u32>,
     cipher: Option<Cipher>,
 }
 
@@ -37,11 +43,46 @@ impl PacketDecoder {
         let packet_len_len = VarInt(packet_len).written_size();
 
         let mut data;
+        if self.compression.is_some() {
+            r = &r[..packet_len as usize];
+
+            let data_len = VarInt::decode(&mut r).map_err(|_| PacketError::TooLong)?.0;
+
+            if !(0..=MAX_PACKET_SIZE).contains(&data_len) {
+                Err(PacketError::OutOfBounds)?
+            }
+
+            // Is this packet compressed?
+            if data_len > 0 {
+                debug_assert!(self.decompress_buf.is_empty());
+
+                self.decompress_buf.put_bytes(0, data_len as usize);
+
+                // TODO: use libdeflater or zune-inflate?
+                let mut z = ZlibDecoder::new(&mut self.decompress_buf[..]);
 
-        // no compression
+                z.write_all(r).map_err(|_| PacketError::FailedWrite)?;
+                z.finish().map_err(|_| PacketError::FailedFinish)?;
 
-        self.buf.advance(packet_len_len);
-        data = self.buf.split_to(packet_len as usize);
+                let total_packet_len = VarInt(packet_len).written_size() + packet_len as usize;
+
+                self.buf.advance(total_packet_len);
+
+                data = self.decompress_buf.split();
+            } else {
+                debug_assert_eq!(data_len, 0);
+
+                let remaining_len = r.len();
+
+                self.buf.advance(packet_len_len + 1);
+
+                data = self.buf.split_to(remaining_len);
+            }
+        } else {
+            // no compression
+            self.buf.advance(packet_len_len);
+            data = self.buf.split_to(packet_len as usize);
+        }
 
         r = &data[..];
         let packet_id = VarInt::decode(&mut r).map_err(|_| PacketError::DecodeID)?;
@@ -64,6 +105,10 @@ impl PacketDecoder {
         self.cipher = Some(cipher);
     }
 
+    pub fn set_compression(&mut self, compression: Option<u32>) {
+        self.compression = compression;
+    }
+
     fn decrypt_bytes(cipher: &mut Cipher, bytes: &mut [u8]) {
         for chunk in bytes.chunks_mut(Cipher::block_size()) {
             let gen_arr = GenericArray::from_mut_slice(chunk);

pumpkin-protocol/src/packet_encoder.rs

@@ -3,6 +3,11 @@ use std::io::Write;
 use aes::cipher::{generic_array::GenericArray, BlockEncryptMut, BlockSizeUser, KeyIvInit};
 use bytes::{BufMut, BytesMut};
 
+use std::io::Read;
+
+use flate2::bufread::ZlibEncoder;
+use flate2::Compression;
+
 use crate::{bytebuf::ByteBuffer, ClientPacket, PacketError, VarInt, MAX_PACKET_SIZE};
 
 type Cipher = cfb8::Encryptor<aes::Aes128>;
@@ -11,7 +16,8 @@ type Cipher = cfb8::Encryptor<aes::Aes128>;
 #[derive(Default)]
 pub struct PacketEncoder {
     buf: BytesMut,
-
+    compress_buf: Vec<u8>,
+    compression: Option<(u32, u32)>,
     cipher: Option<Cipher>,
 }
 
@@ -33,8 +39,64 @@ impl PacketEncoder {
 
         let data_len = self.buf.len() - start_len;
 
-        if false { // compression
+        if let Some((threshold, compression_level)) = self.compression {
+            if data_len > threshold as usize {
+                let mut z =
+                    ZlibEncoder::new(&self.buf[start_len..], Compression::new(compression_level));
+
+                self.compress_buf.clear();
+
+                let data_len_size = VarInt(data_len as i32).written_size();
+
+                let packet_len = data_len_size + z.read_to_end(&mut self.compress_buf).unwrap();
+
+                if packet_len >= MAX_PACKET_SIZE as usize {
+                    Err(PacketError::TooLong)?
+                }
+
+                drop(z);
+
+                self.buf.truncate(start_len);
+
+                let mut writer = (&mut self.buf).writer();
+
+                VarInt(packet_len as i32)
+                    .encode(&mut writer)
+                    .map_err(|_| PacketError::EncodeLength)?;
+                VarInt(data_len as i32)
+                    .encode(&mut writer)
+                    .map_err(|_| PacketError::EncodeData)?;
+                self.buf.extend_from_slice(&self.compress_buf);
+            } else {
+                let data_len_size = 1;
+                let packet_len = data_len_size + data_len;
+
+                if packet_len >= MAX_PACKET_SIZE as usize {
+                    Err(PacketError::TooLong)?
+                }
+
+                let packet_len_size = VarInt(packet_len as i32).written_size();
+
+                let data_prefix_len = packet_len_size + data_len_size;
+
+                self.buf.put_bytes(0, data_prefix_len);
+                self.buf
+                    .copy_within(start_len..start_len + data_len, start_len + data_prefix_len);
+
+                let mut front = &mut self.buf[start_len..];
+
+                VarInt(packet_len as i32)
+                    .encode(&mut front)
+                    .map_err(|_| PacketError::EncodeLength)?;
+                // Zero for no compression on this packet.
+                VarInt(0)
+                    .encode(front)
+                    .map_err(|_| PacketError::EncodeData)?;
+            }
+
+            return Ok(());
         }
+
         let packet_len = data_len;
 
         if packet_len >= MAX_PACKET_SIZE as usize {
@@ -59,6 +121,10 @@ impl PacketEncoder {
         self.cipher = Some(Cipher::new_from_slices(key, key).expect("invalid key"));
     }
 
+    pub fn set_compression(&mut self, compression: Option<(u32, u32)>) {
+        self.compression = compression;
+    }
+
     pub fn take(&mut self) -> BytesMut {
         if let Some(cipher) = &mut self.cipher {
             for chunk in self.buf.chunks_mut(Cipher::block_size()) {

pumpkin/Cargo.toml

@@ -25,8 +25,6 @@ num-bigint = "0.4.6"
 rsa = "0.9.6"
 rsa-der = "0.3.0"
 
-flate2 = "1.0.30"
-
 # authentication
 reqwest = { version = "0.12.5", features = ["json"]}
 

pumpkin/src/client/client_packet.rs

@@ -2,7 +2,7 @@ use num_traits::FromPrimitive;
 use pumpkin_protocol::{
     client::{
         config::{CFinishConfig, CKnownPacks, CRegistryData},
-        login::{CEncryptionRequest, CLoginSuccess},
+        login::{CEncryptionRequest, CLoginSuccess, CSetCompression},
         status::{CPingResponse, CStatusResponse},
     },
     server::{
@@ -134,6 +134,17 @@ impl Client {
             unpack_textures(ele, &server.advanced_config.authentication.textures);
         }
 
+        // enable compression
+        if server.advanced_config.packet_compression.enabled {
+            let threshold = server
+                .advanced_config
+                .packet_compression
+                .compression_threshold;
+            let level = server.advanced_config.packet_compression.compression_level;
+            self.send_packet(CSetCompression::new(threshold.into()));
+            self.set_compression(Some((threshold, level)));
+        }
+
         if let Some(profile) = self.gameprofile.as_ref().cloned() {
             let packet = CLoginSuccess::new(profile.id, profile.name, &profile.properties, false);
             self.send_packet(packet);

pumpkin/src/client/mod.rs

@@ -111,6 +111,12 @@ impl Client {
         Ok(())
     }
 
+    // Compression threshold, Compression level
+    pub fn set_compression(&mut self, compression: Option<(u32, u32)>) {
+        self.dec.set_compression(compression.map(|v| v.0));
+        self.enc.set_compression(compression);
+    }
+
     pub fn is_player(&self) -> bool {
         self.player.is_some()
     }

pumpkin/src/config/mod.rs

@@ -17,6 +17,7 @@ const CURRENT_BASE_VERSION: &str = "1.0.0";
 pub struct AdvancedConfiguration {
     pub commands: Commands,
     pub authentication: Authentication,
+    pub packet_compression: Compression,
 }
 
 #[derive(Deserialize, Serialize)]
@@ -26,6 +27,29 @@ pub struct Commands {
     // TODO: commands...
 }
 
+#[derive(Deserialize, Serialize)]
+// Packet compression
+pub struct Compression {
+    // Is compression enabled ?
+    pub enabled: bool,
+    // The compression threshold used when compression is enabled
+    pub compression_threshold: u32,
+    // A value between 0..9
+    // 1 = Optimize for the best speed of encoding.
+    // 9 = Optimize for the size of data being encoded.
+    pub compression_level: u32,
+}
+
+impl Default for Compression {
+    fn default() -> Self {
+        Self {
+            enabled: true,
+            compression_threshold: 256,
+            compression_level: 4,
+        }
+    }
+}
+
 impl Default for Commands {
     fn default() -> Self {
         Self { use_console: true }
@@ -38,6 +62,7 @@ impl Default for AdvancedConfiguration {
         Self {
             authentication: Authentication::default(),
             commands: Commands::default(),
+            packet_compression: Compression::default(),
         }
     }
 }