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use crate::{buffer::Buff, crypt};
use crate::{protocol, runtime, Backhaul, Session, SessionConfig, StatsGatherer};
use probability::distribution::{Binomial, Distribution};
use smallvec::SmallVec;
use smol::{prelude::*, Task};
use std::{
collections::VecDeque,
net::SocketAddr,
sync::Arc,
time::{Duration, Instant},
};
use super::worker::ClientWorker;
#[derive(Clone)]
pub(crate) struct LowlevelClientConfig {
pub server_addr: SocketAddr,
pub server_pubkey: x25519_dalek::PublicKey,
pub backhaul_gen: Arc<dyn Fn() -> Arc<dyn Backhaul> + 'static + Send + Sync>,
pub num_shards: usize,
pub reset_interval: Option<Duration>,
pub gather: Arc<StatsGatherer>,
}
pub(crate) async fn connect_custom(cfg: LowlevelClientConfig) -> std::io::Result<Session> {
let my_long_sk = x25519_dalek::StaticSecret::new(&mut rand::thread_rng());
let my_eph_sk = x25519_dalek::StaticSecret::new(&mut rand::thread_rng());
let cookie = crypt::Cookie::new(cfg.server_pubkey);
let init_hello = protocol::HandshakeFrame::ClientHello {
long_pk: (&my_long_sk).into(),
eph_pk: (&my_eph_sk).into(),
version: VERSION,
};
for timeout_factor in (0u32..).map(|x| 2u64.pow(x)) {
let backhaul = (cfg.backhaul_gen)();
let init_hello = crypt::LegacyAead::new(&cookie.generate_c2s().next().unwrap())
.pad_encrypt_v1(std::slice::from_ref(&init_hello), 1000);
backhaul.send_to(init_hello, cfg.server_addr).await?;
tracing::trace!("sent client hello");
let res = backhaul
.recv_from()
.or(async {
smol::Timer::after(Duration::from_secs(timeout_factor)).await;
Err(std::io::Error::new(
std::io::ErrorKind::TimedOut,
"timed out",
))
})
.await;
match res {
Ok((buf, _)) => {
for possible_key in cookie.generate_s2c() {
let decrypter = crypt::LegacyAead::new(&possible_key);
let response = decrypter.pad_decrypt_v1(&buf);
for response in response.unwrap_or_default() {
if let protocol::HandshakeFrame::ServerHello {
long_pk,
eph_pk,
resume_token,
} = response
{
tracing::trace!("obtained response from server");
if long_pk.as_bytes() != cfg.server_pubkey.as_bytes() {
return Err(std::io::Error::new(
std::io::ErrorKind::ConnectionRefused,
"bad pubkey",
));
}
let shared_sec =
crypt::triple_ecdh(&my_long_sk, &my_eph_sk, &long_pk, &eph_pk);
return Ok(init_session(cookie, resume_token, shared_sec, cfg.clone()));
}
}
}
}
Err(err) => {
if err.kind() == std::io::ErrorKind::TimedOut {
tracing::trace!(
"timed out to {} with {}s timeout; trying again",
cfg.server_addr,
timeout_factor
);
continue;
}
return Err(err);
}
}
}
unimplemented!()
}
const VERSION: u64 = 3;
fn init_session(
cookie: crypt::Cookie,
resume_token: Buff,
shared_sec: blake3::Hash,
cfg: LowlevelClientConfig,
) -> Session {
let (mut session, back) = Session::new(SessionConfig {
version: VERSION,
gather: cfg.gather.clone(),
session_key: shared_sec.as_bytes().to_vec(),
role: crate::Role::Client,
});
let back = Arc::new(back);
let uploader: Task<anyhow::Result<()>> = runtime::spawn(async move {
let mut workers: Vec<ClientWorker> = (0..cfg.num_shards)
.map(|shard_id| {
ClientWorker::start(
cookie.clone(),
resume_token.clone(),
back.clone(),
shard_id as u8,
cfg.clone(),
)
})
.collect();
let mut fired_workers: VecDeque<ClientWorker> = VecDeque::new();
let mut last_reset = Instant::now();
let mut just_respawned = false;
for ctr in (0..).cycle() {
let to_upload = back.next_outgoing().await?;
let random_worker = ctr % workers.len();
workers[random_worker].send_upload(to_upload).await;
if cfg
.reset_interval
.map(|dur| last_reset.elapsed() > dur)
.unwrap_or_default()
{
tracing::debug!("reset timer expired!");
last_reset = Instant::now();
if just_respawned {
for worker in workers.iter() {
worker.reset_received_count();
}
just_respawned = false;
} else {
let worker_packet_count: SmallVec<[usize; 16]> =
workers.iter().map(|w| w.get_received_count()).collect();
let p_value = uniform_pvalue(&worker_packet_count);
tracing::debug!("p-value = {}; {:?}", p_value, worker_packet_count);
if p_value < 0.01 {
let worst_worker_id = workers
.iter()
.enumerate()
.min_by_key(|(worker_id, worker)| {
let count = worker.get_received_count();
tracing::debug!("worker {} has {}", worker_id, count);
count
})
.map(|x| x.0)
.expect("must have a worst worker");
tracing::debug!("replacing worst worker {}", worst_worker_id);
let new_worker = ClientWorker::start(
cookie.clone(),
resume_token.clone(),
back.clone(),
worst_worker_id as u8,
cfg.clone(),
);
let worst_worker =
std::mem::replace(&mut workers[worst_worker_id], new_worker);
fired_workers.push_back(worst_worker);
if fired_workers.len() > workers.len() {
fired_workers.pop_front();
}
just_respawned = true;
}
}
}
}
unreachable!()
});
session.on_drop(move || {
drop(uploader);
});
session
}
fn uniform_pvalue(vals: &[usize]) -> f64 {
if vals.is_empty() {
return 0.0;
}
let total_count = vals.iter().sum::<usize>();
let min = vals.iter().min().copied().unwrap();
let distro = Binomial::new(total_count, 1.0 / (vals.len() as f64));
distro.distribution(min as f64)
}
