valence/src/protocol.rs
Ryan adc8a4faae Give World ownership over entities, clients, and chunks.
This change was made to make it easier for invariants to be upheld. When
the spatial partition is added, we can ensure that changes to entities
are immediately reflected in the partition. Additionally, chunks being
shared between worlds was a leaky abstraction to begin with and is now
removed. A method in `Config` is now necessary to determine what world a
client should join.

Along with this, most mutable references have been wrapped in a newtype
to ensure that `mem::swap` cannot be used on them, which would break
invariants. This is analogous to `Pin<&mut T>`. The reason we can't use
Pin directly is because it would require unnecessary unsafe code
within the library.
2022-05-16 02:36:14 -07:00

607 lines
15 KiB
Rust

use std::io::{Read, Write};
use std::mem;
use anyhow::{anyhow, ensure, Context};
use arrayvec::ArrayVec;
use bitvec::prelude::*;
use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
use nalgebra_glm::{Number, TVec};
use serde::{Deserialize, Serialize};
use uuid::Uuid;
use crate::var_int::VarInt;
use crate::EntityId;
/// Trait for types that can be written to the Minecraft protocol.
pub trait Encode {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()>;
}
/// Trait for types that can be constructed from the Minecraft protocol.
pub trait Decode: Sized {
fn decode(r: &mut impl Read) -> anyhow::Result<Self>;
}
/// The maximum number of bytes in a single packet.
pub const MAX_PACKET_SIZE: i32 = 2097151;
impl Encode for () {
fn encode(&self, _w: &mut impl Write) -> anyhow::Result<()> {
Ok(())
}
}
impl Decode for () {
fn decode(_r: &mut impl Read) -> anyhow::Result<Self> {
Ok(())
}
}
impl<T: Encode> Encode for &T {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
(*self).encode(w)
}
}
impl Encode for bool {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
w.write_u8(*self as u8)?;
Ok(())
}
}
impl Decode for bool {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
let n = r.read_u8()?;
ensure!(n < 2, "boolean is not 0 or 1");
Ok(n == 1)
}
}
impl Encode for u8 {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
w.write_u8(*self)?;
Ok(())
}
}
impl Decode for u8 {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(r.read_u8()?)
}
}
impl Encode for i8 {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
w.write_i8(*self)?;
Ok(())
}
}
impl Decode for i8 {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(r.read_i8()?)
}
}
impl Encode for u16 {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
w.write_u16::<BigEndian>(*self)?;
Ok(())
}
}
impl Decode for u16 {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(r.read_u16::<BigEndian>()?)
}
}
impl Encode for i16 {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
w.write_i16::<BigEndian>(*self)?;
Ok(())
}
}
impl Decode for i16 {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(r.read_i16::<BigEndian>()?)
}
}
impl Encode for u32 {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
w.write_u32::<BigEndian>(*self)?;
Ok(())
}
}
impl Decode for u32 {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(r.read_u32::<BigEndian>()?)
}
}
impl Encode for i32 {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
w.write_i32::<BigEndian>(*self)?;
Ok(())
}
}
impl Decode for i32 {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(r.read_i32::<BigEndian>()?)
}
}
impl Encode for u64 {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
w.write_u64::<BigEndian>(*self)?;
Ok(())
}
}
impl Decode for u64 {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(r.read_u64::<BigEndian>()?)
}
}
impl Encode for i64 {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
w.write_i64::<BigEndian>(*self)?;
Ok(())
}
}
impl Decode for i64 {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(r.read_i64::<BigEndian>()?)
}
}
impl Encode for f32 {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
ensure!(
self.is_finite(),
"attempt to encode non-finite f32 ({})",
self
);
w.write_f32::<BigEndian>(*self)?;
Ok(())
}
}
impl Decode for f32 {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
let f = r.read_f32::<BigEndian>()?;
ensure!(f.is_finite(), "attempt to decode non-finite f32 ({f})");
Ok(f)
}
}
impl Encode for f64 {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
ensure!(
self.is_finite(),
"attempt to encode non-finite f64 ({})",
self
);
w.write_f64::<BigEndian>(*self)?;
Ok(())
}
}
impl Decode for f64 {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
let f = r.read_f64::<BigEndian>()?;
ensure!(f.is_finite(), "attempt to decode non-finite f64 ({f})");
Ok(f)
}
}
impl<T: Encode> Encode for Option<T> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
match self {
Some(t) => {
true.encode(w)?;
t.encode(w)
}
None => false.encode(w),
}
}
}
impl<T: Decode> Decode for Option<T> {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
if bool::decode(r)? {
Ok(Some(T::decode(r)?))
} else {
Ok(None)
}
}
}
impl<T: Encode> Encode for Box<T> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
self.as_ref().encode(w)
}
}
impl<T: Decode> Decode for Box<T> {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(Box::new(T::decode(r)?))
}
}
impl Encode for Box<str> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
encode_string_bounded(self, 0, 32767, w)
}
}
impl Decode for Box<str> {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(String::decode(r)?.into_boxed_str())
}
}
#[derive(Clone, Copy, Default, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
pub struct BoundedInt<T, const MIN: i64, const MAX: i64>(pub T);
impl<T, const MIN: i64, const MAX: i64> From<T> for BoundedInt<T, MIN, MAX> {
fn from(t: T) -> Self {
Self(t)
}
}
impl<T, const MIN: i64, const MAX: i64> Encode for BoundedInt<T, MIN, MAX>
where
T: Encode + Copy + Into<i64>,
{
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
let val = self.0.into();
ensure!(
(MIN..=MAX).contains(&val),
"Integer is not in bounds while encoding (got {val}, expected {MIN}..={MAX})"
);
self.0.encode(w)
}
}
impl<T, const MIN: i64, const MAX: i64> Decode for BoundedInt<T, MIN, MAX>
where
T: Decode + Copy + Into<i64>,
{
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
let res = T::decode(r)?;
let val = res.into();
ensure!(
(MIN..=MAX).contains(&val),
"Integer is not in bounds while decoding (got {val}, expected {MIN}..={MAX})"
);
Ok(Self(res))
}
}
// TODO: bounded float?
impl Encode for String {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
encode_string_bounded(self, 0, 32767, w)
}
}
impl Decode for String {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
decode_string_bounded(0, 32767, r)
}
}
/// A string with a minimum and maximum character length known at compile time.
/// If the string is not in bounds, an error is generated while
/// encoding/decoding.
///
/// Note that the length is a count of the characters in the string, not bytes.
///
/// When encoded and decoded, the string is VarInt prefixed.
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Default, Hash, Debug)]
pub struct BoundedString<const MIN: usize, const MAX: usize>(pub String);
impl<const MIN: usize, const MAX: usize> Encode for BoundedString<MIN, MAX> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
encode_string_bounded(&self.0, MIN, MAX, w)
}
}
impl<const MIN: usize, const MAX: usize> Decode for BoundedString<MIN, MAX> {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
decode_string_bounded(MIN, MAX, r).map(Self)
}
}
impl<const MIN: usize, const MAX: usize> From<String> for BoundedString<MIN, MAX> {
fn from(s: String) -> Self {
Self(s)
}
}
impl<T: Encode> Encode for Vec<T> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
encode_array_bounded(self, 0, usize::MAX, w)
}
}
impl<T: Decode> Decode for Vec<T> {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
decode_array_bounded(0, usize::MAX, r)
}
}
impl<T: Encode> Encode for Box<[T]> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
encode_array_bounded(self, 0, usize::MAX, w)
}
}
impl<T: Decode> Decode for Box<[T]> {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
decode_array_bounded(0, usize::MAX, r).map(|v| v.into_boxed_slice())
}
}
impl<T: Encode, const N: usize> Encode for [T; N] {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
encode_array_bounded(self, N, N, w)
}
}
impl<T: Decode, const N: usize> Decode for [T; N] {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
let mut elems = ArrayVec::new();
for _ in 0..N {
elems.push(T::decode(r)?);
}
elems
.into_inner()
.map_err(|_| unreachable!("mismatched array size"))
}
}
impl<T: Encode, const N: usize> Encode for TVec<T, N> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
encode_array_bounded(self.as_slice(), N, N, w)
}
}
impl<T: Decode + Number, const N: usize> Decode for TVec<T, N> {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(<[T; N]>::decode(r)?.into())
}
}
/// An array with a minimum and maximum character length known at compile time.
/// If the array is not in bounds, an error is generated while
/// encoding/decoding.
///
/// When encoding/decoding, the array is VarInt prefixed.
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Default, Hash, Debug)]
pub struct BoundedArray<T, const MIN: usize = 0, const MAX: usize = { usize::MAX }>(pub Vec<T>);
impl<T: Encode, const MIN: usize, const MAX: usize> Encode for BoundedArray<T, MIN, MAX> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
encode_array_bounded(&self.0, MIN, MAX, w)
}
}
impl<T: Decode, const MIN: usize, const MAX: usize> Decode for BoundedArray<T, MIN, MAX> {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
decode_array_bounded(MIN, MAX, r).map(Self)
}
}
impl<T, const MIN: usize, const MAX: usize> From<Vec<T>> for BoundedArray<T, MIN, MAX> {
fn from(v: Vec<T>) -> Self {
Self(v)
}
}
impl Encode for Uuid {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
w.write_u128::<BigEndian>(self.as_u128())?;
Ok(())
}
}
impl Decode for Uuid {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(Uuid::from_u128(r.read_u128::<BigEndian>()?))
}
}
impl Encode for nbt::Blob {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
Ok(nbt::to_writer(w, self, None)?)
}
}
impl Decode for nbt::Blob {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
Ok(nbt::from_reader(r)?)
}
}
/// Wrapper type acting as a bridge between Serde and [Encode]/[Decode] through
/// the NBT format.
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Default, Hash, Debug)]
pub struct Nbt<T>(pub T);
impl<T: Serialize> Encode for Nbt<T> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
let mut enc = nbt::ser::Encoder::new(w, None);
self.0.serialize(&mut enc)?;
Ok(())
}
}
impl<'a, T: Deserialize<'a>> Decode for Nbt<T> {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
let mut dec = nbt::de::Decoder::new(r);
Ok(Nbt(Deserialize::deserialize(&mut dec)?))
}
}
impl Encode for BitVec<u64> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
encode_array_bounded(self.as_raw_slice(), 0, usize::MAX, w)
}
}
impl Decode for BitVec<u64> {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
BitVec::try_from_vec(Vec::decode(r)?)
.map_err(|_| anyhow!("Array is too long for bit vector"))
}
}
impl Encode for BitBox<u64> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
encode_array_bounded(self.as_raw_slice(), 0, usize::MAX, w)
}
}
impl Decode for BitBox<u64> {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
BitVec::decode(r).map(|v| v.into_boxed_bitslice())
}
}
/// When decoding, reads the rest of the data in a packet and stuffs it into a
/// `Vec<u8>`. When encoding, the data is inserted into the packet with no
/// length prefix.
#[derive(Clone, Debug)]
pub struct ReadToEnd(pub Vec<u8>);
impl Decode for ReadToEnd {
fn decode(r: &mut impl Read) -> anyhow::Result<Self> {
let mut buf = Vec::new();
r.read_to_end(&mut buf)?;
Ok(ReadToEnd(buf))
}
}
impl Encode for ReadToEnd {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
w.write_all(&self.0).map_err(|e| e.into())
}
}
impl Encode for Option<EntityId> {
fn encode(&self, w: &mut impl Write) -> anyhow::Result<()> {
match self {
Some(id) => VarInt(
id.to_network_id()
.checked_add(1)
.context("i32::MAX is unrepresentable as an optional VarInt")?,
),
None => VarInt(0),
}
.encode(w)
}
}
fn encode_array_bounded<T: Encode>(
s: &[T],
min: usize,
max: usize,
w: &mut impl Write,
) -> anyhow::Result<()> {
assert!(min <= max);
let len = s.len();
ensure!(
(min..=max).contains(&len),
"Length of array is out of bounds while encoding (got {len}, expected {min}..={max})"
);
ensure!(
len <= i32::MAX as usize,
"Length of array ({len}) exceeds i32::MAX"
);
VarInt(len as i32).encode(w)?;
for t in s {
t.encode(w)?;
}
Ok(())
}
pub(crate) fn encode_string_bounded(
s: &str,
min: usize,
max: usize,
w: &mut impl Write,
) -> anyhow::Result<()> {
assert!(min <= max, "Bad min and max");
let char_count = s.chars().count();
ensure!(
(min..=max).contains(&char_count),
"Char count of string is out of bounds while encoding (got {char_count}, expected \
{min}..={max})"
);
encode_array_bounded(s.as_bytes(), 0, usize::MAX, w)
}
pub(crate) fn decode_string_bounded(
min: usize,
max: usize,
r: &mut impl Read,
) -> anyhow::Result<String> {
assert!(min <= max);
let bytes = decode_array_bounded(min, max.saturating_mul(4), r)?;
let string = String::from_utf8(bytes)?;
let char_count = string.chars().count();
ensure!(
(min..=max).contains(&char_count),
"Char count of string is out of bounds while decoding (got {char_count}, expected \
{min}..={max}"
);
Ok(string)
}
pub(crate) fn decode_array_bounded<T: Decode>(
min: usize,
max: usize,
r: &mut impl Read,
) -> anyhow::Result<Vec<T>> {
assert!(min <= max);
let len = VarInt::decode(r)?.0;
ensure!(
len >= 0 && (min..=max).contains(&(len as usize)),
"Length of array is out of bounds while decoding (got {len}, needed {min}..={max})",
);
// Don't allocate more than what would roughly fit in a single packet in case we
// get a malicious array length.
let cap = (MAX_PACKET_SIZE as usize / mem::size_of::<T>().max(1)).min(len as usize);
let mut res = Vec::with_capacity(cap);
for _ in 0..len {
res.push(T::decode(r)?);
}
Ok(res)
}