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assembly buffer

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This commit is contained in:
John Smith
2023-06-23 12:05:28 -04:00
parent d21f580de2
commit e4f97cfefa
8 changed files with 219 additions and 9 deletions
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241
veilid-core/src/network_manager/native/protocol/assembly_buffer.rs
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@@ -1,241 +0,0 @@
use super::*;
use range_set_blaze::RangeSetBlaze;
use std::io::{Error, ErrorKind};
use std::sync::atomic::{AtomicU16, Ordering};
// AssemblyBuffer Version 1 properties
const VERSION_1: u8 = 1;
type LengthType = u16;
type SequenceType = u16;
const HEADER_LEN: usize = 8;
const MAX_LEN: usize = LengthType::MAX as usize;
// XXX: keep statistics on all drops and why we dropped them
// XXX: move to config
const FRAGMENT_LEN: usize = 1280 - HEADER_LEN;
const MAX_CONCURRENT_HOSTS: usize = 256;
const MAX_ASSEMBLIES_PER_HOST: usize = 256;
const MAX_BUFFER_PER_HOST: usize = 256 * 1024;
const MAX_ASSEMBLY_AGE_US: u64 = 10_000_000;
/////////////////////////////////////////////////////////
#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
struct PeerKey {
remote_addr: SocketAddr,
}
#[derive(Clone, Eq, PartialEq)]
struct MessageAssembly {
timestamp: Timestamp,
seq: SequenceType,
data: Vec<u8>,
parts: RangeSetBlaze<LengthType>,
}
#[derive(Clone, Eq, PartialEq)]
struct PeerMessages {
assemblies: LinkedList<MessageAssembly>,
}
impl PeerMessages {
pub fn new() -> Self {
Self {
assemblies: LinkedList::new(),
}
}
pub fn insert_fragment(
&mut self,
seq: SequenceType,
off: LengthType,
len: LengthType,
chunk: &[u8],
) -> Option<Vec<u8>> {
// Get the current timestamp
let cur_ts = get_timestamp();
// Get the assembly this belongs to by its sequence number
for a in self.assemblies {}
}
}
/////////////////////////////////////////////////////////
struct AssemblyBufferInner {
peer_message_map: HashMap<PeerKey, PeerMessages>,
}
struct AssemblyBufferUnlockedInner {
outbound_lock_table: AsyncTagLockTable<SocketAddr>,
next_seq: AtomicU16,
}
/// Packet reassembly and fragmentation handler
/// No retry, no acknowledgment, no flow control
/// Just trying to survive lower path MTU for larger messages
#[derive(Clone)]
pub struct AssemblyBuffer {
inner: Arc<Mutex<AssemblyBufferInner>>,
unlocked_inner: Arc<AssemblyBufferUnlockedInner>,
}
impl AssemblyBuffer {
fn new_unlocked_inner() -> AssemblyBufferUnlockedInner {
AssemblyBufferUnlockedInner {
outbound_lock_table: AsyncTagLockTable::new(),
next_seq: AtomicU16::new(0),
}
}
fn new_inner() -> AssemblyBufferInner {
AssemblyBufferInner {
peer_message_map: HashMap::new(),
}
}
pub fn new() -> Self {
Self {
inner: Arc::new(Mutex::new(Self::new_inner())),
unlocked_inner: Arc::new(Self::new_unlocked_inner()),
}
}
/// Receive a packet chunk and add to the message assembly
/// if a message has been completely, return it
pub fn insert_frame(&self, frame: &[u8], remote_addr: SocketAddr) -> Option<Vec<u8>> {
// If we receive a zero length frame, send it
if frame.len() == 0 {
return Some(frame.to_vec());
}
// If we receive a frame smaller than or equal to the length of the header, drop it
// or if this frame is larger than our max message length, then drop it
if frame.len() <= HEADER_LEN || frame.len() > MAX_LEN {
return None;
}
// --- Decode the header
// Drop versions we don't understand
if frame[0] != VERSION_1 {
return None;
}
// Version 1 header
let seq = SequenceType::from_be_bytes(frame[2..4].try_into().unwrap());
let off = LengthType::from_be_bytes(frame[4..6].try_into().unwrap());
let len = LengthType::from_be_bytes(frame[6..HEADER_LEN].try_into().unwrap());
let chunk = &frame[HEADER_LEN..];
// See if we have a whole message and not a fragment
if off == 0 && len as usize == chunk.len() {
return Some(frame.to_vec());
}
// Drop fragments with offsets greater than or equal to the message length
if off >= len {
return None;
}
// Drop fragments where the chunk would be applied beyond the message length
if off as usize + chunk.len() > len as usize {
return None;
}
// Get or create the peer message assemblies
// and drop the packet if we have too many peers
let mut inner = self.inner.lock();
let peer_key = PeerKey { remote_addr };
let peer_count = inner.peer_message_map.len();
match inner.peer_message_map.entry(peer_key) {
std::collections::hash_map::Entry::Occupied(mut e) => {
let peer_messages = e.get_mut();
// Insert the fragment and see what comes out
peer_messages.insert_fragment(seq, off, len, chunk)
}
std::collections::hash_map::Entry::Vacant(v) => {
// See if we have room for one more
if peer_count == MAX_CONCURRENT_HOSTS {
return None;
}
// Add the peer
let peer_messages = v.insert(PeerMessages::new());
// Insert the fragment and see what comes out
peer_messages.insert_fragment(seq, off, len, chunk)
}
}
}
/// Add framing to chunk to send to the wire
fn frame_chunk(chunk: &[u8], offset: usize, message_len: usize, seq: SequenceType) -> Vec<u8> {
assert!(chunk.len() > 0);
assert!(message_len <= MAX_LEN);
assert!(offset + chunk.len() <= message_len);
let off: LengthType = offset as LengthType;
let len: LengthType = message_len as LengthType;
unsafe {
// Uninitialized vector, careful!
let mut out = unaligned_u8_vec_uninit(chunk.len() + HEADER_LEN);
// Write out header
out[0] = VERSION_1;
out[1] = 0; // reserved
out[2..4].copy_from_slice(&seq.to_be_bytes()); // sequence number
out[4..6].copy_from_slice(&off.to_be_bytes()); // offset of chunk inside message
out[6..HEADER_LEN].copy_from_slice(&len.to_be_bytes()); // total length of message
// Write out body
out[HEADER_LEN..].copy_from_slice(chunk);
out
}
}
/// Split a message into packets and send them serially, ensuring
/// that they are sent consecutively to a particular remote address,
/// never interleaving packets from one message and other to minimize reassembly problems
pub async fn split_message<S, F>(
&self,
data: Vec<u8>,
remote_addr: SocketAddr,
sender: S,
) -> std::io::Result<NetworkResult<()>>
where
S: Fn(Vec<u8>, SocketAddr) -> F,
F: Future<Output = std::io::Result<NetworkResult<()>>>,
{
if data.len() > MAX_LEN {
return Err(Error::from(ErrorKind::InvalidData));
}
// Do not frame or split anything zero bytes long, just send it
if data.len() == 0 {
return sender(data, remote_addr).await;
}
// Lock per remote addr
let _tag_lock = self
.unlocked_inner
.outbound_lock_table
.lock_tag(remote_addr)
.await;
// Get a message seq
let seq = self.unlocked_inner.next_seq.fetch_add(1, Ordering::Relaxed);
// Chunk it up
let mut offset = 0usize;
let message_len = data.len();
for chunk in data.chunks(FRAGMENT_LEN) {
// Frame chunk
let framed_chunk = Self::frame_chunk(chunk, offset, message_len, seq);
// Send chunk
network_result_try!(sender(framed_chunk, remote_addr).await?);
// Go to next chunk
offset += chunk.len()
}
Ok(NetworkResult::value(()))
}
}

2
veilid-core/src/network_manager/native/protocol/mod.rs
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@@ -4,8 +4,6 @@ pub mod udp;
pub mod wrtc;
pub mod ws;
mod assembly_buffer;
use super::*;
use std::io;

1
veilid-core/src/network_manager/native/protocol/udp.rs
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@@ -1,5 +1,4 @@
use super::*;
use assembly_buffer::*;
use sockets::*;
#[derive(Clone)]