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base: dkanus:bb1f73a755753221159eb247553b5b4d0c9c9042
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dkanus:master
dkanus:feature_link
dkanus:feature_database
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compare: dkanus:0a868521974fd84859506a3f9ef4d427bf05c2b9
Branches Tags
dkanus:feature_link
dkanus:feature_database
dkanus:master

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194
src/link/mod.rs
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@ -4,24 +4,11 @@ use std::str;
extern crate custom_error; extern crate custom_error;
use custom_error::custom_error; use custom_error::custom_error;
// Defines how many bytes is used to encode "AMOUNT" field in the response from ue-server about const RECEIVED_FIELD_SIZE: usize = 4;
// amount of bytes it received since the last update const LENGTH_FIELD_SIZE: usize = 4;
const UE_RECEIVED_FIELD_SIZE: usize = 4; const HEAD_RECEIVED: u8 = 85;
// Defines how many bytes is used to encode "LENGTH" field, describing length of const HEAD_MESSAGE: u8 = 42;
// next JSON message from ue-server const MAX_MESSAGE_LENGTH: usize = 0xA00000;
const UE_LENGTH_FIELD_SIZE: usize = 4;
// Value indicating that next byte sequence from ue-server reports amount of bytes received by
// that server so far. Value itself is arbitrary.
const HEAD_UE_RECEIVED: u8 = 85;
// Value indicating that next byte sequence from ue-server contains JSON message.
// Value itself is arbitrary.
const HEAD_UE_MESSAGE: u8 = 42;
// Maximum allowed size of JSON message sent from ue-server.
const MAX_UE_MESSAGE_LENGTH: usize = 25 * 1024 * 1024;
// We do not expect to receive more that this much messages at once from ue-server
const EXPECTED_LIMIT_TO_UE_MESSAGES: usize = 100;
custom_error! { pub ReadingStreamError custom_error! { pub ReadingStreamError
InvalidHead{input: u8} = "Invalid byte used as a HEAD: {input}", InvalidHead{input: u8} = "Invalid byte used as a HEAD: {input}",
@ -41,23 +28,20 @@ pub struct MessageReader {
is_broken: bool, is_broken: bool,
reading_state: ReadingState, reading_state: ReadingState,
read_bytes: usize, read_bytes: usize,
buffer: [u8; 4],
current_message_length: usize, current_message_length: usize,
current_message: Vec<u8>, current_message: Vec<u8>,
read_messages: VecDeque<String>, read_messages: VecDeque<String>,
ue_received_bytes: u64, next_received_bytes: u32,
received_bytes: u64,
} }
/// For converting byte stream that is expected from the ue-server into actual messages. /// For converting byte stream expected to be generated by Acedia mod from the game server into
/// Expected format is a sequence of either: /// actual messages. Expected format is a sequence of either:
/// 1. [HEAD_UE_RECEIVED: marker byte | 1 byte] /// [HEAD_RECEIVED: 1 byte] [amount of bytes received by game server since last update: 4 bytes]
/// [AMOUNT: amount of bytes received by ue-server since last update | 4 bytes: u32 BE] /// [HEAD_MESSAGE: 1 byte] [length of the message: 4 bytes] [utf8-encoded string: ??? bytes]
/// 2. [HEAD_UE_MESSAGE: marker byte | 1 byte] /// On any invalid input enters a failure state (can be checked by `is_broken()`) and
/// [LENGTH: length of the JSON message in utf8 encoding | 4 bytes: u32 BE]
/// [PAYLOAD: utf8-encoded string | `LENGTH` bytes]
/// On any invalid input enters into a failure state (can be checked by `is_broken()`) and
/// never recovers from it. /// never recovers from it.
/// Use either `push_byte()` or `push()` to input byte stream from ue-server and `pop()` to /// Use either `push_byte()` or `push()` to input byte stream from game server and `pop()` to
/// retrieve resulting messages. /// retrieve resulting messages.
impl MessageReader { impl MessageReader {
pub fn new() -> MessageReader { pub fn new() -> MessageReader {
@ -65,12 +49,11 @@ impl MessageReader {
is_broken: false, is_broken: false,
reading_state: ReadingState::Head, reading_state: ReadingState::Head,
read_bytes: 0, read_bytes: 0,
buffer: [0; 4],
current_message_length: 0, current_message_length: 0,
// Will be recreated with `with_capacity` in `push_byte()`
current_message: Vec::new(), current_message: Vec::new(),
read_messages: VecDeque::with_capacity(EXPECTED_LIMIT_TO_UE_MESSAGES), read_messages: VecDeque::new(),
ue_received_bytes: 0, next_received_bytes: 0,
received_bytes: 0,
} }
} }
@ -80,30 +63,34 @@ impl MessageReader {
} }
match &self.reading_state { match &self.reading_state {
ReadingState::Head => { ReadingState::Head => {
if input == HEAD_UE_RECEIVED { if input == HEAD_RECEIVED {
self.change_state(ReadingState::ReceivedBytes); self.reading_state = ReadingState::ReceivedBytes;
} else if input == HEAD_UE_MESSAGE { } else if input == HEAD_MESSAGE {
self.change_state(ReadingState::Length); self.reading_state = ReadingState::Length;
} else { } else {
self.is_broken = true; self.is_broken = true;
return Err(ReadingStreamError::InvalidHead { input }); return Err(ReadingStreamError::InvalidHead { input });
} }
} }
ReadingState::ReceivedBytes => { ReadingState::ReceivedBytes => {
self.buffer[self.read_bytes] = input; self.next_received_bytes = self.next_received_bytes << 8;
self.next_received_bytes += input as u32;
self.read_bytes += 1; self.read_bytes += 1;
if self.read_bytes >= UE_RECEIVED_FIELD_SIZE { if self.read_bytes >= RECEIVED_FIELD_SIZE {
self.ue_received_bytes += array_of_u8_to_u32(self.buffer) as u64; self.received_bytes += self.next_received_bytes as u64;
self.change_state(ReadingState::Head); self.next_received_bytes = 0;
self.read_bytes = 0;
self.reading_state = ReadingState::Head;
} }
} }
ReadingState::Length => { ReadingState::Length => {
self.buffer[self.read_bytes] = input; self.current_message_length = self.current_message_length << 8;
self.current_message_length += input as usize;
self.read_bytes += 1; self.read_bytes += 1;
if self.read_bytes >= UE_LENGTH_FIELD_SIZE { if self.read_bytes >= LENGTH_FIELD_SIZE {
self.current_message_length = array_of_u8_to_u32(self.buffer) as usize; self.read_bytes = 0;
self.change_state(ReadingState::Payload); self.reading_state = ReadingState::Payload;
if self.current_message_length > MAX_UE_MESSAGE_LENGTH { if self.current_message_length > MAX_MESSAGE_LENGTH {
self.is_broken = true; self.is_broken = true;
return Err(ReadingStreamError::MessageTooLong { return Err(ReadingStreamError::MessageTooLong {
length: self.current_message_length, length: self.current_message_length,
@ -114,7 +101,7 @@ impl MessageReader {
} }
ReadingState::Payload => { ReadingState::Payload => {
self.current_message.push(input); self.current_message.push(input);
self.read_bytes += 1; self.read_bytes += 1 as usize;
if self.read_bytes >= self.current_message_length { if self.read_bytes >= self.current_message_length {
match str::from_utf8(&self.current_message) { match str::from_utf8(&self.current_message) {
Ok(next_message) => self.read_messages.push_front(next_message.to_owned()), Ok(next_message) => self.read_messages.push_front(next_message.to_owned()),
@ -125,7 +112,8 @@ impl MessageReader {
}; };
self.current_message.clear(); self.current_message.clear();
self.current_message_length = 0; self.current_message_length = 0;
self.change_state(ReadingState::Head); self.read_bytes = 0;
self.reading_state = ReadingState::Head;
} }
} }
} }
@ -143,56 +131,44 @@ impl MessageReader {
self.read_messages.pop_back() self.read_messages.pop_back()
} }
pub fn ue_received_bytes(&self) -> u64 { pub fn received_bytes(&self) -> u64 {
self.ue_received_bytes self.received_bytes
} }
pub fn is_broken(&self) -> bool { pub fn is_broken(&self) -> bool {
self.is_broken self.is_broken
} }
fn change_state(&mut self, next_state: ReadingState) {
self.read_bytes = 0;
self.reading_state = next_state;
}
}
fn array_of_u8_to_u32(bytes: [u8; 4]) -> u64 {
(u64::from(bytes[0]) << 24)
+ (u64::from(bytes[1]) << 16)
+ (u64::from(bytes[2]) << 8)
+ (u64::from(bytes[3]))
} }
#[test] #[test]
fn message_push_byte() { fn message_push_byte() {
let mut reader = MessageReader::new(); let mut reader = MessageReader::new();
reader.push_byte(HEAD_UE_MESSAGE).unwrap(); reader.push_byte(HEAD_MESSAGE).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(13).unwrap(); reader.push_byte(13).unwrap();
reader.push_byte(b'H').unwrap(); reader.push_byte(0x48).unwrap(); // H
reader.push_byte(b'e').unwrap(); reader.push_byte(0x65).unwrap(); // e
reader.push_byte(b'l').unwrap(); reader.push_byte(0x6c).unwrap(); // l
reader.push_byte(b'l').unwrap(); reader.push_byte(0x6c).unwrap(); // l
reader.push_byte(b'o').unwrap(); reader.push_byte(0x6f).unwrap(); // o
reader.push_byte(b',').unwrap(); reader.push_byte(0x2c).unwrap(); // ,
reader.push_byte(b' ').unwrap(); reader.push_byte(0x20).unwrap(); // <space>
reader.push_byte(b'w').unwrap(); reader.push_byte(0x77).unwrap(); // w
reader.push_byte(b'o').unwrap(); reader.push_byte(0x6f).unwrap(); // o
reader.push_byte(b'r').unwrap(); reader.push_byte(0x72).unwrap(); // r
reader.push_byte(b'l').unwrap(); reader.push_byte(0x6c).unwrap(); // l
reader.push_byte(b'd').unwrap(); reader.push_byte(0x64).unwrap(); // d
reader.push_byte(b'!').unwrap(); reader.push_byte(0x21).unwrap(); // <exclamation mark>
reader.push_byte(HEAD_UE_MESSAGE).unwrap(); reader.push_byte(HEAD_MESSAGE).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(3).unwrap(); reader.push_byte(3).unwrap();
reader.push_byte(b'Y').unwrap(); reader.push_byte(0x59).unwrap(); // Y
reader.push_byte(b'o').unwrap(); reader.push_byte(0x6f).unwrap(); // o
reader.push_byte(b'!').unwrap(); reader.push_byte(0x21).unwrap(); // <exclamation mark>
assert_eq!(reader.pop().unwrap(), "Hello, world!"); assert_eq!(reader.pop().unwrap(), "Hello, world!");
assert_eq!(reader.pop().unwrap(), "Yo!"); assert_eq!(reader.pop().unwrap(), "Yo!");
assert_eq!(reader.pop(), None); assert_eq!(reader.pop(), None);
@ -201,47 +177,47 @@ fn message_push_byte() {
#[test] #[test]
fn received_push_byte() { fn received_push_byte() {
let mut reader = MessageReader::new(); let mut reader = MessageReader::new();
reader.push_byte(HEAD_UE_RECEIVED).unwrap(); reader.push_byte(HEAD_RECEIVED).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(243).unwrap(); reader.push_byte(243).unwrap();
assert_eq!(reader.ue_received_bytes(), 243); assert_eq!(reader.received_bytes(), 243);
reader.push_byte(HEAD_UE_RECEIVED).unwrap(); reader.push_byte(HEAD_RECEIVED).unwrap();
reader.push_byte(65).unwrap(); reader.push_byte(65).unwrap();
reader.push_byte(25).unwrap(); reader.push_byte(25).unwrap();
reader.push_byte(178).unwrap(); reader.push_byte(178).unwrap();
reader.push_byte(4).unwrap(); reader.push_byte(4).unwrap();
assert_eq!(reader.ue_received_bytes(), 1092203255); assert_eq!(reader.received_bytes(), 1092203255);
reader.push_byte(HEAD_UE_RECEIVED).unwrap(); reader.push_byte(HEAD_RECEIVED).unwrap();
reader.push_byte(231).unwrap(); reader.push_byte(231).unwrap();
reader.push_byte(34).unwrap(); reader.push_byte(34).unwrap();
reader.push_byte(154).unwrap(); reader.push_byte(154).unwrap();
assert_eq!(reader.ue_received_bytes(), 1092203255); assert_eq!(reader.received_bytes(), 1092203255);
} }
#[test] #[test]
fn mixed_push_byte() { fn mixed_push_byte() {
let mut reader = MessageReader::new(); let mut reader = MessageReader::new();
reader.push_byte(HEAD_UE_RECEIVED).unwrap(); reader.push_byte(HEAD_RECEIVED).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(243).unwrap(); reader.push_byte(243).unwrap();
reader.push_byte(HEAD_UE_MESSAGE).unwrap(); reader.push_byte(HEAD_MESSAGE).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(3).unwrap(); reader.push_byte(3).unwrap();
reader.push_byte(b'Y').unwrap(); reader.push_byte(0x59).unwrap(); // Y
reader.push_byte(b'o').unwrap(); reader.push_byte(0x6f).unwrap(); // o
reader.push_byte(b'!').unwrap(); reader.push_byte(0x21).unwrap(); // <exclamation mark>
reader.push_byte(HEAD_UE_RECEIVED).unwrap(); reader.push_byte(HEAD_RECEIVED).unwrap();
reader.push_byte(65).unwrap(); reader.push_byte(65).unwrap();
reader.push_byte(25).unwrap(); reader.push_byte(25).unwrap();
reader.push_byte(178).unwrap(); reader.push_byte(178).unwrap();
reader.push_byte(4).unwrap(); reader.push_byte(4).unwrap();
assert_eq!(reader.ue_received_bytes(), 1092203255); assert_eq!(reader.received_bytes(), 1092203255);
assert_eq!(reader.pop().unwrap(), "Yo!"); assert_eq!(reader.pop().unwrap(), "Yo!");
assert_eq!(reader.pop(), None); assert_eq!(reader.pop(), None);
} }
@ -251,27 +227,27 @@ fn pushing_many_bytes_at_once() {
let mut reader = MessageReader::new(); let mut reader = MessageReader::new();
reader reader
.push(&[ .push(&[
HEAD_UE_RECEIVED, HEAD_RECEIVED,
0, 0,
0, 0,
0, 0,
243, 243,
HEAD_UE_MESSAGE, HEAD_MESSAGE,
0, 0,
0, 0,
0, 0,
3, 3,
b'Y', 0x59, // Y
b'o', 0x6f, // o
b'!', 0x21, // <exclamation mark>
HEAD_UE_RECEIVED, HEAD_RECEIVED,
65, 65,
25, 25,
178, 178,
4, 4,
]) ])
.unwrap(); .unwrap();
assert_eq!(reader.ue_received_bytes(), 1092203255); assert_eq!(reader.received_bytes(), 1092203255);
assert_eq!(reader.pop().unwrap(), "Yo!"); assert_eq!(reader.pop().unwrap(), "Yo!");
assert_eq!(reader.pop(), None); assert_eq!(reader.pop(), None);
} }
@ -279,7 +255,7 @@ fn pushing_many_bytes_at_once() {
#[test] #[test]
fn generates_error_invalid_head() { fn generates_error_invalid_head() {
let mut reader = MessageReader::new(); let mut reader = MessageReader::new();
reader.push_byte(HEAD_UE_RECEIVED).unwrap(); reader.push_byte(HEAD_RECEIVED).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
@ -294,16 +270,14 @@ fn generates_error_invalid_head() {
#[test] #[test]
fn generates_error_message_too_long() { fn generates_error_message_too_long() {
let mut reader = MessageReader::new(); let mut reader = MessageReader::new();
let huge_length = MAX_UE_MESSAGE_LENGTH + 1; reader.push_byte(HEAD_MESSAGE).unwrap();
let bytes = (huge_length as u32).to_be_bytes(); // Max length right now is `0xA00000`
reader.push_byte(0).unwrap();
reader.push_byte(HEAD_UE_MESSAGE).unwrap(); reader.push_byte(0xA0).unwrap();
reader.push_byte(bytes[0]).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(bytes[1]).unwrap();
reader.push_byte(bytes[2]).unwrap();
assert!(!reader.is_broken()); assert!(!reader.is_broken());
reader reader
.push_byte(bytes[3]) .push_byte(1)
.expect_err("Testing failing on exceeding allowed message length"); .expect_err("Testing failing on exceeding allowed message length");
assert!(reader.is_broken()); assert!(reader.is_broken());
} }
@ -311,7 +285,7 @@ fn generates_error_message_too_long() {
#[test] #[test]
fn generates_error_invalid_unicode() { fn generates_error_invalid_unicode() {
let mut reader = MessageReader::new(); let mut reader = MessageReader::new();
reader.push_byte(HEAD_UE_MESSAGE).unwrap(); reader.push_byte(HEAD_MESSAGE).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();
reader.push_byte(0).unwrap(); reader.push_byte(0).unwrap();