geph5_client/
get_dialer.rs

1use std::time::{Duration, Instant, SystemTime};
2
3use anyctx::AnyCtx;
4use anyhow::Context;
5
6use arrayref::array_ref;
7use async_native_tls::TlsConnector;
8use ed25519_dalek::VerifyingKey;
9
10use geph5_broker_protocol::{
11    AccountLevel, ExitCategory, ExitDescriptor, GetRoutesArgs, NetStatus, RouteDescriptor,
12};
13use isocountry::CountryCode;
14use itertools::Itertools;
15use ordered_float::OrderedFloat;
16use rand::seq::SliceRandom;
17use serde::{Deserialize, Serialize};
18use sillad::{
19    dialer::{DialerExt, DynDialer, FailingDialer},
20    tcp::TcpDialer,
21};
22use sillad_conntest::ConnTestDialer;
23use sillad_hex::HexDialer;
24use sillad_meeklike::MeeklikeDialer;
25use sillad_sosistab3::{dialer::SosistabDialer, Cookie};
26
27use crate::{
28    auth::get_connect_token,
29    broker::{broker_client, get_net_status},
30    client::{Config, CtxField},
31    device_metadata::get_device_metadata,
32    vpn::smart_vpn_whitelist,
33};
34
35#[derive(Serialize, Deserialize, Clone, Debug)]
36#[serde(rename_all = "snake_case")]
37pub enum ExitConstraint {
38    Auto,
39    Direct(String),
40    Hostname(String),
41    Country(CountryCode),
42    CountryCity(CountryCode, String),
43}
44
45/// Gets a sillad Dialer that produces a single, pre-authentication pipe, as well as the public key.
46pub async fn get_dialer(
47    ctx: &AnyCtx<Config>,
48) -> anyhow::Result<(VerifyingKey, ExitDescriptor, DynDialer)> {
49    static SEMAPH: CtxField<
50        smol::lock::Mutex<Option<(VerifyingKey, ExitDescriptor, DynDialer, SystemTime)>>,
51    > = |_| smol::lock::Mutex::new(None);
52    let mut cached_value = ctx.get(SEMAPH).lock().await;
53
54    if let Some(inner) = cached_value.clone() {
55        if inner.3.elapsed()? < Duration::from_secs(120) {
56            return Ok((inner.0, inner.1, inner.2));
57        }
58    }
59
60    let res = get_dialer_inner(ctx).await;
61    match res {
62        Ok(val) => {
63            *cached_value = Some((val.0, val.1.clone(), val.2.clone(), SystemTime::now()));
64            Ok((val.0, val.1, val.2))
65        }
66        Err(err) => {
67            tracing::warn!("failed to get dialer: {:?}", err);
68            if let Some(val) = cached_value.clone() {
69                tracing::warn!("returning stale value instead");
70                Ok((val.0, val.1, val.2))
71            } else {
72                Err(err)
73            }
74        }
75    }
76}
77
78async fn get_dialer_inner(
79    ctx: &AnyCtx<Config>,
80) -> anyhow::Result<(VerifyingKey, ExitDescriptor, DynDialer)> {
81    // If the user specified a direct constraint, handle that path immediately:
82    if let ExitConstraint::Direct(dir) = &ctx.init().exit_constraint {
83        let (dir, pubkey_hex) = dir
84            .split_once('/')
85            .context("did not find / in a direct constraint")?;
86        let pubkey = VerifyingKey::from_bytes(
87            hex::decode(pubkey_hex)
88                .context("cannot decode pubkey as hex")?
89                .as_slice()
90                .try_into()
91                .context("pubkey wrong length")?,
92        )?;
93        let dest_addr = *smol::net::resolve(dir)
94            .await?
95            .choose(&mut rand::thread_rng())
96            .context("could not resolve destination for direct exit connection")?;
97        smart_vpn_whitelist(ctx, dest_addr.ip());
98        return Ok((
99            pubkey,
100            ExitDescriptor {
101                c2e_listen: "0.0.0.0:0".parse()?,
102                b2e_listen: "0.0.0.0:0".parse()?,
103                country: CountryCode::ABW,
104                city: "".to_string(),
105                load: 0.0,
106                expiry: 0,
107            },
108            ConnTestDialer {
109                ping_count: 1,
110                inner: TcpDialer { dest_addr },
111            }
112            .dynamic(),
113        ));
114    }
115
116    // Otherwise, we need to pick an exit from the broker based on user constraints.
117    let (level, conn_token, sig) = get_connect_token(ctx)
118        .await
119        .context("could not get connect token")?;
120
121    let net_status_verified = get_net_status(ctx).await?;
122
123    tracing::debug!(
124        "verified netstatus: {}",
125        serde_json::to_string(
126            &net_status_verified
127                .exits
128                .iter()
129                .map(|s| &s.1 .1)
130                .collect_vec()
131        )?
132    );
133
134    // Use our new helper function to pick the best exit:
135    let rendezvous_key = blake3::hash(serde_json::to_string(&ctx.init().credentials)?.as_bytes());
136    let (pubkey, exit) = pick_exit_with_constraint(
137        rendezvous_key,
138        &ctx.init().exit_constraint,
139        level,
140        &net_status_verified,
141    )?;
142
143    tracing::debug!(exit = ?exit, "narrowed down choice of exit");
144    smart_vpn_whitelist(ctx, exit.c2e_listen.ip());
145
146    tracing::debug!(token = %conn_token, "CONN TOKEN");
147
148    let start = Instant::now();
149    let metadata = if let Ok(metadata) = get_device_metadata(ctx).await {
150        tracing::info!(
151            metadata = debug(&metadata),
152            elapsed = debug(start.elapsed()),
153            "DEVICE METADATA OBTAINED"
154        );
155        serde_json::to_value(&metadata)?
156    } else {
157        tracing::warn!("CANNOT GET DEVICE METADATA, PROCEEDING NONETHELESS");
158        serde_json::Value::Null
159    };
160
161    // Also get potential “bridge routes”:
162    let broker = broker_client(ctx)?;
163    let bridge_routes = broker
164        .get_routes_v2(GetRoutesArgs {
165            token: conn_token,
166            sig,
167            exit_b2e: exit.b2e_listen,
168            client_metadata: metadata,
169        })
170        .await?
171        .map_err(|e| anyhow::anyhow!("broker refused to serve bridge routes: {e}"))?;
172    tracing::debug!(
173        "bridge routes obtained: {}",
174        serde_json::to_string(&bridge_routes)?
175    );
176
177    let bridge_dialer = route_to_dialer(ctx, &bridge_routes);
178
179    Ok((*pubkey, exit.clone(), bridge_dialer))
180}
181
182/// A helper that filters the verified exits by the user’s `ExitConstraint`,
183/// then picks the exit with the lowest load.
184fn pick_exit_with_constraint<'a>(
185    rendezvous_key: blake3::Hash,
186    constraint: &ExitConstraint,
187    level: AccountLevel,
188    net_status: &'a NetStatus,
189) -> anyhow::Result<(&'a VerifyingKey, &'a ExitDescriptor)> {
190    let all_exits = net_status.exits.values();
191
192    // Figure out which fields we need to match
193    let mut country_constraint = None;
194    let mut city_constraint = None;
195    let mut hostname_constraint = None;
196
197    match constraint {
198        ExitConstraint::Hostname(host) => hostname_constraint = Some(host.clone()),
199        ExitConstraint::Country(country) => country_constraint = Some(*country),
200        ExitConstraint::CountryCity(country, city) => {
201            country_constraint = Some(*country);
202            city_constraint = Some(city.clone());
203        }
204        ExitConstraint::Auto => {}
205        ExitConstraint::Direct(_) => panic!("should not reach here"),
206    }
207
208    let filtered: Vec<_> = all_exits
209        .filter(|(_, exit, meta)| {
210            let mut pass = match country_constraint {
211                Some(c) => exit.country == c,
212                None => true,
213            };
214            pass &= match &city_constraint {
215                Some(city) => exit.city == *city,
216                None => true,
217            };
218            pass &= match &hostname_constraint {
219                Some(hn) => exit.b2e_listen.ip().to_string() == *hn,
220                None => true,
221            };
222            if matches!(constraint, ExitConstraint::Auto) {
223                pass &= meta.category == ExitCategory::Core;
224            }
225            pass &= meta.allowed_levels.contains(&level);
226            pass
227        })
228        .collect();
229
230    if filtered.is_empty() {
231        anyhow::bail!("no exits match the constraints")
232    }
233
234    // If any matched, we use load-sensitive rendezvous hashing
235    let first = filtered
236        .iter()
237        .min_by_key(|rh| {
238            let (_, exit, _) = **rh;
239            let hash = blake3::keyed_hash(
240                rendezvous_key.as_bytes(),
241                exit.b2e_listen.ip().to_string().as_bytes(),
242            );
243            let hash = &hash.as_bytes()[..];
244            let hash = u64::from_be_bytes(*array_ref![hash, 0, 8]) as f64 / u64::MAX as f64;
245            let weight = (1.0 - (exit.load as f64)).powi(2);
246            let picker = -hash.ln() / weight;
247            OrderedFloat(picker)
248        })
249        .unwrap();
250    Ok((&first.0, &first.1))
251}
252
253fn route_to_dialer(ctx: &AnyCtx<Config>, route: &RouteDescriptor) -> DynDialer {
254    use sillad_native_tls::TlsDialer;
255
256    match route {
257        RouteDescriptor::Tcp(addr) => {
258            smart_vpn_whitelist(ctx, addr.ip());
259            let addr = *addr;
260            TcpDialer { dest_addr: addr }.dynamic()
261        }
262        RouteDescriptor::Sosistab3 { cookie, lower } => {
263            let inner = route_to_dialer(ctx, lower);
264            SosistabDialer {
265                inner,
266                cookie: Cookie::new(cookie),
267            }
268            .dynamic()
269        }
270        RouteDescriptor::Race(inside) => inside
271            .iter()
272            .map(|s| route_to_dialer(ctx, s))
273            .reduce(|a, b| a.race(b).dynamic())
274            .unwrap_or_else(|| FailingDialer.dynamic()),
275        RouteDescriptor::Fallback(a) => a
276            .iter()
277            .map(|s| route_to_dialer(ctx, s))
278            .reduce(|a, b| a.fallback(b).dynamic())
279            .unwrap_or_else(|| FailingDialer.dynamic()),
280        RouteDescriptor::Timeout {
281            milliseconds,
282            lower,
283        } => route_to_dialer(ctx, lower)
284            .timeout(Duration::from_millis(*milliseconds as _))
285            .dynamic(),
286        RouteDescriptor::Delay {
287            milliseconds,
288            lower,
289        } => route_to_dialer(ctx, lower)
290            .delay(Duration::from_millis((*milliseconds).into()))
291            .dynamic(),
292        RouteDescriptor::ConnTest { ping_count, lower } => {
293            let lower = route_to_dialer(ctx, lower);
294            ConnTestDialer {
295                inner: lower,
296                ping_count: *ping_count as _,
297            }
298            .dynamic()
299        }
300        RouteDescriptor::Hex { lower } => {
301            let lower = route_to_dialer(ctx, lower);
302            HexDialer { inner: lower }.dynamic()
303        }
304        RouteDescriptor::Other(_) => FailingDialer.dynamic(),
305        RouteDescriptor::PlainTls { sni_domain, lower } => {
306            let lower = route_to_dialer(ctx, lower);
307            TlsDialer::new(
308                lower,
309                TlsConnector::new()
310                    .use_sni(sni_domain.is_some())
311                    .danger_accept_invalid_certs(true)
312                    .danger_accept_invalid_hostnames(true)
313                    .min_protocol_version(None)
314                    .max_protocol_version(None),
315                sni_domain
316                    .clone()
317                    .unwrap_or_else(|| "example.com".to_string()),
318            )
319            .dynamic()
320        }
321        RouteDescriptor::Meeklike { key, lower } => {
322            let lower = route_to_dialer(ctx, lower);
323            MeeklikeDialer {
324                inner: lower,
325                key: *blake3::hash(key.as_bytes()).as_bytes(),
326            }
327            .dynamic()
328        }
329    }
330}
geph5_client/get_dialer.rs

geph5_client/
get_dialer.rs
