net_mc/packet/
mod.rs

1use anyhow::{bail, Result};
2use std::{
3    io::{self, Read, Write},
4    vec,
5};
6mod builder;
7pub mod raw;
8pub mod types;
9use crate::types::*;
10use flate2::{
11    bufread::{ZlibDecoder, ZlibEncoder},
12    Compression,
13};
14
15pub trait Encoder: Sized {
16    fn write_to(&self, w: &mut impl io::Write) -> Result<()>;
17}
18
19impl<'a, T> Encoder for &'a T
20where
21    T: Encoder,
22{
23    fn write_to(&self, w: &mut impl io::Write) -> Result<()> {
24        T::write_to(*self, w)
25    }
26}
27pub trait Decoder: Sized {
28    fn read_from(r: &mut impl io::Read) -> Result<Self>;
29}
30
31pub trait Packet: Encoder + Decoder {
32    const ID: VarInt;
33    fn encode(&self) -> Result<RawPacket> {
34        let mut buf = Vec::new();
35        self.write_to(&mut buf)?;
36        Ok(RawPacket {
37            id: Self::ID,
38            data: buf,
39        })
40    }
41
42    fn decode(raw: RawPacket) -> Result<Self> {
43        let mut buf = raw.data.as_slice();
44        Self::read_from(&mut buf)
45    }
46}
47
48#[derive(Debug)]
49pub struct RawPacket {
50    pub id: VarInt,
51    pub data: Vec<u8>,
52}
53
54impl io::Write for RawPacket {
55    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
56        self.data.write(buf)
57    }
58
59    fn flush(&mut self) -> io::Result<()> {
60        self.data.flush()
61    }
62}
63
64impl RawPacket {
65    pub fn unpack(r: &mut impl io::Read, threshold: i32) -> Result<Self> {
66        if threshold >= 0 {
67            Self::unpack_with_compression(r, threshold)
68        } else {
69            Self::unpack_without_compression(r)
70        }
71    }
72
73    fn unpack_without_compression(r: &mut impl io::Read) -> Result<Self> {
74        let len = VarInt::read_from(r)?.0 as usize;
75        let mut buf = vec![0; len];
76        r.read_exact(&mut buf)?;
77
78        let mut buf = buf.as_slice();
79        let id = VarInt::read_from(&mut buf)?;
80
81        Ok(Self {
82            id,
83            data: buf.to_vec(),
84        })
85    }
86
87    fn unpack_with_compression(r: &mut impl io::Read, threshold: i32) -> Result<Self> {
88        let pk_len = VarInt::read_from(r)?.0 as usize;
89        let mut buf = vec![0u8; pk_len];
90        r.read_exact(&mut buf)?;
91        let mut buf = buf.as_slice();
92        let data_len = VarInt::read_from(&mut buf)?.0;
93
94        let id: VarInt;
95
96        let data: Vec<u8>;
97
98        if data_len != 0 {
99            if data_len < threshold {
100                bail!(
101                    "data length is smaller than threshold: {} < {}",
102                    data_len,
103                    threshold
104                );
105            }
106
107            if data_len > 2097152 {
108                bail!(
109                    "data length is larger than protocol maximum: {} > {}",
110                    data_len,
111                    2097152
112                );
113            }
114
115            let mut decoder = ZlibDecoder::new(&buf[..]);
116            let buf = &mut Vec::new();
117
118            decoder.read_to_end(buf)?;
119
120            let mut buf = buf.as_slice();
121
122            id = VarInt::read_from(&mut buf)?;
123
124            data = buf.to_vec();
125        } else {
126            id = VarInt::read_from(&mut buf)?;
127
128            data = buf.to_vec();
129        }
130
131        Ok(Self { id, data })
132    }
133
134    pub fn pack(&mut self, w: &mut impl io::Write, threshold: i32) -> Result<()> {
135        if threshold >= 0 {
136            self.pack_with_compression(w, threshold)
137        } else {
138            self.pack_without_compression(w)
139        }
140    }
141
142    fn pack_with_compression(&mut self, w: &mut impl io::Write, threshold: i32) -> Result<()> {
143        let mut buf = Vec::new();
144        self.id.write_to(&mut buf)?;
145        buf.write_all(&self.data)?;
146        let data_len = buf.len();
147
148        if data_len < threshold as usize {
149            let mut buf2 = Vec::new();
150            VarInt(0).write_to(&mut buf2)?;
151            buf2.write_all(&buf)?;
152            VarInt(buf2.len() as i32).write_to(w)?;
153            w.write_all(&buf2)?;
154        } else {
155            let mut encoder = ZlibEncoder::new(buf.as_slice(), Compression::default());
156            let mut buf2 = Vec::new();
157            VarInt(data_len as i32).write_to(&mut buf2)?;
158            encoder.read_to_end(&mut buf2)?;
159            VarInt(buf2.len() as i32).write_to(w)?;
160            w.write_all(&buf2)?;
161        }
162
163        //if self.data.len() < threshold as usize {
164        //    let buf = &mut Vec::new();
165        //    VarInt(0).write_to(buf)?;
166        //    self.id.write_to(buf)?;
167        //    buf.write_all(&self.data)?;
168        //    VarInt(buf.len() as i32).write_to(w)?;
169        //    w.write_all(buf)?;
170        //} else {
171        //    let buf: &mut Vec<u8> = &mut Vec::new();
172        //    self.id.write_to(buf)?;
173        //    buf.write_all(&self.data)?;
174        //    let len = VarInt(buf.len() as i32);
175        //
176        //    let buf2 = &mut Vec::new();
177        //    len.write_to(buf2)?;
178        //    ZlibEncoder::new(buf.as_slice(), Compression::default()).read_to_end(buf2)?;
179        //
180        //    let len = VarInt(buf2.len() as i32);
181        //    len.write_to(w)?;
182        //    w.write_all(buf2)?;
183        //}
184        Ok(())
185    }
186
187    fn pack_without_compression(&self, w: &mut impl io::Write) -> Result<()> {
188        let buf = &mut Vec::new();
189
190        self.id.write_to(buf)?;
191        buf.write_all(self.data.as_slice())?;
192
193        VarInt(buf.len() as i32).write_to(w)?;
194
195        w.write_all(buf.as_slice())?;
196
197        Ok(())
198    }
199}
net_mc/packet/mod.rs

net_mc/packet/
mod.rs
