rqbit/crates/dht/src/routing_table.rs
Igor Katson 0478577a72
Nothing
2023-11-28 09:23:05 +00:00

691 lines
20 KiB
Rust

use std::{
net::SocketAddr,
time::{Duration, Instant},
};
use librqbit_core::id20::Id20;
use serde::{ser::SerializeMap, Deserialize, Serialize};
use tracing::debug;
use crate::{INACTIVITY_TIMEOUT, RESPONSE_TIMEOUT};
#[derive(Debug, Clone, Serialize, Deserialize)]
enum BucketTreeNodeData {
// TODO: maybe replace that with SmallVec<8>?
Leaf(Vec<RoutingTableNode>),
LeftRight(usize, usize),
}
#[derive(Debug, Clone, Serialize, Deserialize)]
struct BucketTreeNode {
bits: u8,
#[serde(serialize_with = "crate::utils::serialize_id20")]
start: Id20,
#[serde(serialize_with = "crate::utils::serialize_id20")]
end_inclusive: Id20,
data: BucketTreeNodeData,
}
#[derive(Debug, Clone)]
pub struct BucketTree {
data: Vec<BucketTreeNode>,
}
impl<'de> Deserialize<'de> for BucketTree {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
struct Visitor;
impl<'de> serde::de::Visitor<'de> for Visitor {
type Value = BucketTree;
fn expecting(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
write!(f, "a map with key \"flat\"")
}
fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
where
A: serde::de::MapAccess<'de>,
{
let mut data: Option<Vec<BucketTreeNode>> = None;
loop {
match map.next_key::<String>()?.as_deref() {
Some("flat") => {
let buckets = map.next_value::<Vec<BucketTreeNode>>()?;
data = Some(buckets)
}
Some(_) => {
map.next_value::<serde::de::IgnoredAny>()?;
}
None => {
use serde::de::Error;
match data.take() {
Some(data) => return Ok(BucketTree { data }),
None => return Err(A::Error::missing_field("flat")),
}
}
}
}
}
}
deserializer.deserialize_map(Visitor)
}
}
impl Serialize for BucketTree {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
struct Node<'a> {
tree: &'a BucketTree,
idx: usize,
}
impl<'a> Serialize for Node<'a> {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
let mut map = serializer.serialize_map(None)?;
let node = &self.tree.data[self.idx];
map.serialize_entry("bits", &node.bits)?;
map.serialize_entry("start", &node.start.as_string())?;
map.serialize_entry("end", &node.end_inclusive.as_string())?;
match &node.data {
BucketTreeNodeData::Leaf(nodes) => {
map.serialize_entry("nodes", &nodes)?;
}
BucketTreeNodeData::LeftRight(l, r) => {
map.serialize_entry(
"left",
&(Node {
idx: *l,
tree: self.tree,
}),
)?;
map.serialize_entry(
"right",
&(Node {
idx: *r,
tree: self.tree,
}),
)?;
}
}
map.end()
}
}
let mut map = serializer.serialize_map(None)?;
map.serialize_entry("nodes_len", &self.data.len())?;
map.serialize_entry("nodes_capacity", &self.data.capacity())?;
map.serialize_entry("node_memory_bytes", &std::mem::size_of::<BucketTreeNode>())?;
map.serialize_entry(
"nodes_memory_bytes",
&(std::mem::size_of::<BucketTreeNode>() * self.data.capacity()),
)?;
map.serialize_entry("tree", &Node { tree: self, idx: 0 })?;
map.serialize_entry("flat", &self.data)?;
map.end()
}
}
pub struct BucketTreeIterator<'a> {
tree: &'a BucketTree,
current: std::slice::Iter<'a, RoutingTableNode>,
queue: Vec<usize>,
}
impl<'a> BucketTreeIterator<'a> {
fn new(tree: &'a BucketTree) -> Self {
let mut queue = Vec::new();
let mut current = 0;
let current_slice = loop {
match &tree.data[current].data {
BucketTreeNodeData::Leaf(nodes) => break nodes.iter(),
BucketTreeNodeData::LeftRight(left, right) => {
queue.push(*right);
current = *left;
}
}
};
BucketTreeIterator {
tree,
current: current_slice,
queue,
}
}
}
impl<'a> Iterator for BucketTreeIterator<'a> {
type Item = &'a RoutingTableNode;
fn next(&mut self) -> Option<Self::Item> {
if let Some(v) = self.current.next() {
return Some(v);
};
loop {
let idx = self.queue.pop()?;
match &self.tree.data[idx].data {
BucketTreeNodeData::Leaf(nodes) => {
self.current = nodes.iter();
match self.current.next() {
Some(v) => return Some(v),
None => continue,
}
}
BucketTreeNodeData::LeftRight(left, right) => {
self.queue.push(*right);
self.queue.push(*left);
continue;
}
}
}
}
}
fn compute_split_start_end(
start: Id20,
end_inclusive: Id20,
bits: u8,
) -> ((Id20, Id20), (Id20, Id20)) {
let changing_bit = 160 - bits;
let new_left_end = {
let mut c = end_inclusive;
c.set_bit(changing_bit, false);
c
};
let new_right_start = {
let mut c = start;
c.set_bit(changing_bit, true);
c
};
debug_assert!(
start < new_left_end,
"expected start({:?}) < new_left_end({:?}); start={:?}, end={:?}, bits={}",
start,
new_left_end,
start,
end_inclusive,
bits
);
debug_assert!(
new_left_end < new_right_start,
"expected new_left_end({:?}) < new_right_start({:?}); start={:?}, end={:?}, bits={}",
new_left_end,
new_right_start,
start,
end_inclusive,
bits
);
debug_assert!(
new_right_start < end_inclusive,
"expected new_right_start({:?}) < end_inclusive({:?}); start={:?}, end={:?}, bits={}",
new_right_start,
end_inclusive,
start,
end_inclusive,
bits
);
((start, new_left_end), (new_right_start, end_inclusive))
}
#[derive(Debug)]
pub enum InsertResult {
WasExisting,
ReplacedBad(RoutingTableNode),
Added,
Ignored,
}
impl BucketTree {
pub fn new() -> Self {
BucketTree {
data: vec![BucketTreeNode {
bits: 160,
start: Id20([0u8; 20]),
end_inclusive: Id20([0xff; 20]),
data: BucketTreeNodeData::Leaf(Vec::new()),
}],
}
}
pub fn iter(&self) -> BucketTreeIterator<'_> {
BucketTreeIterator::new(self)
}
fn get_leaf(&self, id: &Id20) -> usize {
let mut idx = 0;
loop {
let node = &self.data[idx];
match node.data {
BucketTreeNodeData::Leaf(_) => return idx,
BucketTreeNodeData::LeftRight(left_idx, right_idx) => {
let left = &self.data[left_idx];
if *id >= left.start && *id <= left.end_inclusive {
idx = left_idx;
continue;
};
idx = right_idx;
}
}
}
}
pub fn get_mut(&mut self, id: &Id20) -> Option<&mut RoutingTableNode> {
let idx = self.get_leaf(id);
match &mut self.data[idx].data {
BucketTreeNodeData::Leaf(nodes) => nodes.iter_mut().find(|b| b.id == *id),
BucketTreeNodeData::LeftRight(_, _) => unreachable!(),
}
}
pub fn add_node(
&mut self,
self_id: &Id20,
id: Id20,
addr: SocketAddr,
on_questionable_node: impl FnMut(SocketAddr) -> bool,
) -> InsertResult {
let idx = self.get_leaf(&id);
self.insert_into_leaf(idx, self_id, id, addr, on_questionable_node)
}
fn insert_into_leaf(
&mut self,
mut idx: usize,
self_id: &Id20,
id: Id20,
addr: SocketAddr,
mut on_questionable_node: impl FnMut(SocketAddr) -> bool,
) -> InsertResult {
// The loop here is for this case:
// in case we split a node into two, and it degenerates into all the leaves
// being on one side, we'll need to split again "recursively" until there's space
// for the new node.
// The loop is to remove the recursion. NOTE: it might have compiled to tail recursion
// anyway, but whatever, did not check.
loop {
let leaf = &mut self.data[idx];
let nodes = match &mut leaf.data {
BucketTreeNodeData::Leaf(nodes) => nodes,
BucketTreeNodeData::LeftRight(_, _) => unreachable!(),
};
// if already found, quit
if nodes.iter().any(|r| r.id == id) {
return InsertResult::WasExisting;
}
let mut new_node = RoutingTableNode {
id,
addr,
last_request: None,
last_response: None,
last_query: None,
outstanding_queries_in_a_row: 0,
};
if nodes.len() < 8 {
nodes.push(new_node);
nodes.sort_by_key(|n| n.id);
return InsertResult::Added;
}
// Ping first questionable node
if let Some(questionable_node) = nodes
.iter_mut()
.find(|r| matches!(r.status(), NodeStatus::Questionable))
{
if on_questionable_node(questionable_node.addr) {
questionable_node.mark_outgoing_request();
}
}
// Try replace a bad node
if let Some(bad_node) = nodes
.iter_mut()
.find(|r| matches!(r.status(), NodeStatus::Bad))
{
std::mem::swap(bad_node, &mut new_node);
nodes.sort_by_key(|n| n.id);
debug!("replaced bad node {:?}", new_node);
return InsertResult::ReplacedBad(new_node);
}
// if our id is not inside, don't bother.
if *self_id < leaf.start || *self_id > leaf.end_inclusive {
return InsertResult::Ignored;
}
// Split
let ((ls, le), (rs, re)) =
compute_split_start_end(leaf.start, leaf.end_inclusive, leaf.bits);
let (mut ld, mut rd) = (Vec::new(), Vec::new());
for node in nodes.drain(0..) {
if node.id < rs {
ld.push(node);
} else {
rd.push(node)
}
}
let left = BucketTreeNode {
bits: leaf.bits - 1,
start: ls,
end_inclusive: le,
data: BucketTreeNodeData::Leaf(ld),
};
let right = BucketTreeNode {
bits: leaf.bits - 1,
start: rs,
end_inclusive: re,
data: BucketTreeNodeData::Leaf(rd),
};
let left_idx = {
let l = self.data.len();
self.data.push(left);
l
};
let right_idx = {
let l = self.data.len();
self.data.push(right);
l
};
self.data[idx].data = BucketTreeNodeData::LeftRight(left_idx, right_idx);
if id < rs {
idx = left_idx
} else {
idx = right_idx
}
}
}
}
impl Default for BucketTree {
fn default() -> Self {
Self::new()
}
}
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RoutingTableNode {
#[serde(serialize_with = "crate::utils::serialize_id20")]
id: Id20,
addr: SocketAddr,
#[serde(skip)]
last_request: Option<Instant>,
#[serde(skip)]
last_response: Option<Instant>,
#[serde(skip)]
last_query: Option<Instant>,
#[serde(skip)]
outstanding_queries_in_a_row: usize,
}
pub enum NodeStatus {
Good,
Questionable,
Bad,
Unknown,
}
impl RoutingTableNode {
pub fn id(&self) -> Id20 {
self.id
}
pub fn addr(&self) -> SocketAddr {
self.addr
}
pub fn status(&self) -> NodeStatus {
match (self.last_request, self.last_response, self.last_query) {
(None, _, _) => NodeStatus::Unknown,
// Nodes become bad when they fail to respond to multiple queries in a row.
(Some(last_request), _, _)
if last_request.elapsed() > RESPONSE_TIMEOUT
&& self.outstanding_queries_in_a_row >= 2 =>
{
NodeStatus::Bad
}
// A good node is a node has responded to one of our queries within the last 15 minutes.
// A node is also good if it has ever responded to one of our queries and has sent
// us a query within the last 15 minutes.
(Some(_), Some(last_activity), _) | (Some(_), Some(_), Some(last_activity))
if last_activity.elapsed() < INACTIVITY_TIMEOUT =>
{
NodeStatus::Good
}
// After 15 minutes of inactivity, a node becomes questionable
(_, _, Some(last_activity)) | (_, Some(last_activity), _)
if last_activity.elapsed() > INACTIVITY_TIMEOUT =>
{
NodeStatus::Questionable
}
(Some(_), _, _) => NodeStatus::Unknown,
}
}
pub fn mark_outgoing_request(&mut self) {
self.last_request = Some(Instant::now());
self.outstanding_queries_in_a_row += 1;
}
pub fn mark_last_query(&mut self) {
self.last_query = Some(Instant::now());
}
pub fn mark_response(&mut self) {
let now = Instant::now();
self.last_response = Some(now);
if self.last_request.is_none() {
self.last_request = Some(now);
}
self.outstanding_queries_in_a_row = 0;
}
}
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RoutingTable {
#[serde(serialize_with = "crate::utils::serialize_id20")]
id: Id20,
size: usize,
buckets: BucketTree,
}
impl RoutingTable {
pub fn new(id: Id20) -> Self {
Self {
id,
buckets: BucketTree::new(),
size: 0,
}
}
pub fn id(&self) -> Id20 {
self.id
}
pub fn len(&self) -> usize {
self.size
}
pub fn sorted_by_distance_from(&self, id: Id20) -> Vec<&RoutingTableNode> {
let mut result = Vec::with_capacity(self.size);
for node in self.buckets.iter() {
result.push(node);
}
result.sort_by_key(|n| id.distance(&n.id));
result
}
pub fn add_node(
&mut self,
id: Id20,
addr: SocketAddr,
on_questionable_node: impl FnMut(SocketAddr) -> bool,
) -> InsertResult {
let res = self
.buckets
.add_node(&self.id, id, addr, on_questionable_node);
let replaced = match &res {
InsertResult::WasExisting => false,
InsertResult::ReplacedBad(..) => true,
InsertResult::Added => true,
InsertResult::Ignored => false,
};
if replaced {
self.size += 1;
}
res
}
pub fn mark_outgoing_request(&mut self, id: &Id20) -> bool {
let r = match self.buckets.get_mut(id) {
Some(r) => r,
None => return false,
};
r.mark_outgoing_request();
true
}
pub fn mark_response(&mut self, id: &Id20) -> bool {
let r = match self.buckets.get_mut(id) {
Some(r) => r,
None => return false,
};
r.mark_response();
true
}
pub fn mark_last_query(&mut self, id: &Id20) -> bool {
let r = match self.buckets.get_mut(id) {
Some(r) => r,
None => return false,
};
r.mark_last_query();
true
}
}
#[cfg(test)]
mod tests {
use std::{
io::Cursor,
net::{Ipv4Addr, SocketAddr, SocketAddrV4},
str::FromStr,
};
use librqbit_core::id20::Id20;
use rand::Rng;
use crate::routing_table::compute_split_start_end;
use super::RoutingTable;
#[test]
fn compute_split_start_end_root() {
let start = Id20([0u8; 20]);
let end = Id20([0xff; 20]);
assert_eq!(
compute_split_start_end(start, end, 160),
(
(
start,
Id20::from_str("7fffffffffffffffffffffffffffffffffffffff").unwrap()
),
(
Id20::from_str("8000000000000000000000000000000000000000").unwrap(),
end
)
)
)
}
#[test]
fn compute_split_start_end_second_split() {
let start = Id20::from_str("8000000000000000000000000000000000000000").unwrap();
let end = Id20([0xff; 20]);
assert_eq!(
compute_split_start_end(start, end, 159),
(
(
start,
Id20::from_str("bfffffffffffffffffffffffffffffffffffffff").unwrap()
),
(
Id20::from_str("c000000000000000000000000000000000000000").unwrap(),
end
)
)
)
}
#[test]
fn compute_split_start_end_3() {
let start = Id20::from_str("8000000000000000000000000000000000000000").unwrap();
let end = Id20([0xff; 20]);
assert_eq!(
compute_split_start_end(start, end, 159),
(
(
start,
Id20::from_str("bfffffffffffffffffffffffffffffffffffffff").unwrap()
),
(
Id20::from_str("c000000000000000000000000000000000000000").unwrap(),
end
)
)
)
}
fn random_id_20() -> Id20 {
let mut id20 = [0u8; 20];
rand::thread_rng().fill(&mut id20);
Id20(id20)
}
fn generate_socket_addr() -> SocketAddr {
let mut ipv4_addr = [0u8; 6];
rand::thread_rng().fill(&mut ipv4_addr);
let ip = Ipv4Addr::new(ipv4_addr[0], ipv4_addr[1], ipv4_addr[2], ipv4_addr[3]);
let port = ((ipv4_addr[4] as u16) << 8) + (ipv4_addr[5] as u16);
SocketAddrV4::new(ip, port).into()
}
fn generate_table(length: Option<usize>) -> RoutingTable {
let my_id = random_id_20();
let mut rtable = RoutingTable::new(my_id);
for _ in 0..length.unwrap_or(16536) {
let other_id = random_id_20();
let addr = generate_socket_addr();
rtable.add_node(other_id, addr, |_| false);
}
rtable
}
#[test]
fn test_iter_is_ordered() {
let table = generate_table(None);
let mut it = table.buckets.iter();
let mut previous = it.next().unwrap();
for node in it {
assert!(node.id() > previous.id());
previous = node;
}
}
#[test]
fn test_sorted_by_distance_from() {
let id = random_id_20();
let rtable = generate_table(None);
assert_eq!(rtable.sorted_by_distance_from(id).len(), rtable.size);
}
#[test]
fn serialize_deserialize_routing_table() {
let table = generate_table(Some(1000));
let v = serde_json::to_vec(&table).unwrap();
let _: RoutingTable = serde_json::from_reader(Cursor::new(v)).unwrap();
}
}