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_sosistab3::{dialer::SosistabDialer, Cookie};
24
25use smol_timeout2::TimeoutExt as _;
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(10) {
56            return Ok((inner.0, inner.1, inner.2));
57        }
58    }
59
60    let res = get_dialer_inner(ctx)
61        .timeout(Duration::from_secs(15))
62        .await
63        .ok_or_else(|| anyhow::anyhow!("get_dialer_inner timed out"))
64        .and_then(|x| x);
65    match res {
66        Ok(val) => {
67            *cached_value = Some((val.0, val.1.clone(), val.2.clone(), SystemTime::now()));
68            Ok((val.0, val.1, val.2))
69        }
70        Err(err) => {
71            tracing::warn!("failed to get dialer: {:?}", err);
72            if let Some(val) = cached_value.clone() {
73                tracing::warn!("returning stale value instead");
74                Ok((val.0, val.1, val.2))
75            } else {
76                Err(err)
77            }
78        }
79    }
80}
81
82async fn get_dialer_inner(
83    ctx: &AnyCtx<Config>,
84) -> anyhow::Result<(VerifyingKey, ExitDescriptor, DynDialer)> {
85    // If the user specified a direct constraint, handle that path immediately:
86    if let ExitConstraint::Direct(dir) = &ctx.init().exit_constraint {
87        let (dir, pubkey_hex) = dir
88            .split_once('/')
89            .context("did not find / in a direct constraint")?;
90        let pubkey = VerifyingKey::from_bytes(
91            hex::decode(pubkey_hex)
92                .context("cannot decode pubkey as hex")?
93                .as_slice()
94                .try_into()
95                .context("pubkey wrong length")?,
96        )?;
97        let dest_addr = *smol::net::resolve(dir)
98            .await?
99            .choose(&mut rand::thread_rng())
100            .context("could not resolve destination for direct exit connection")?;
101        smart_vpn_whitelist(ctx, dest_addr.ip());
102        return Ok((
103            pubkey,
104            ExitDescriptor {
105                c2e_listen: "0.0.0.0:0".parse()?,
106                b2e_listen: "0.0.0.0:0".parse()?,
107                country: CountryCode::ABW,
108                city: "".to_string(),
109                load: 0.0,
110                expiry: 0,
111            },
112            ConnTestDialer {
113                ping_count: 1,
114                inner: TcpDialer { dest_addr },
115            }
116            .dynamic(),
117        ));
118    }
119
120    // Otherwise, we need to pick an exit from the broker based on user constraints.
121    let (level, conn_token, sig) = get_connect_token(ctx)
122        .await
123        .context("could not get connect token")?;
124
125    let net_status_verified = get_net_status(ctx).await?;
126
127    tracing::debug!(
128        "verified netstatus: {}",
129        serde_json::to_string(
130            &net_status_verified
131                .exits
132                .iter()
133                .map(|s| &s.1 .1)
134                .collect_vec()
135        )?
136    );
137
138    // Use our new helper function to pick the best exit:
139    let rendezvous_key = blake3::hash(serde_json::to_string(&ctx.init().credentials)?.as_bytes());
140    let (pubkey, exit) = pick_exit_with_constraint(
141        rendezvous_key,
142        &ctx.init().exit_constraint,
143        level,
144        &net_status_verified,
145    )?;
146
147    tracing::debug!(exit = ?exit, "narrowed down choice of exit");
148    smart_vpn_whitelist(ctx, exit.c2e_listen.ip());
149
150    tracing::debug!(token = %conn_token, "CONN TOKEN");
151
152    let start = Instant::now();
153    let metadata = if let Ok(metadata) = get_device_metadata(ctx).await {
154        tracing::info!(
155            metadata = debug(&metadata),
156            elapsed = debug(start.elapsed()),
157            "DEVICE METADATA OBTAINED"
158        );
159        serde_json::to_value(&metadata)?
160    } else {
161        tracing::warn!("CANNOT GET DEVICE METADATA, PROCEEDING NONETHELESS");
162        serde_json::Value::Null
163    };
164
165    // Also get potential “bridge routes”:
166    let broker = broker_client(ctx)?;
167    let bridge_routes = broker
168        .get_routes_v2(GetRoutesArgs {
169            token: conn_token,
170            sig,
171            exit_b2e: exit.b2e_listen,
172            client_metadata: metadata,
173        })
174        .await?
175        .map_err(|e| anyhow::anyhow!("broker refused to serve bridge routes: {e}"))?;
176    tracing::debug!(
177        "bridge routes obtained: {}",
178        serde_json::to_string(&bridge_routes)?
179    );
180
181    let bridge_dialer = route_to_dialer(ctx, &bridge_routes);
182
183    Ok((*pubkey, exit.clone(), bridge_dialer))
184}
185
186/// A helper that filters the verified exits by the user’s `ExitConstraint`,
187/// then picks the exit with the lowest load.
188fn pick_exit_with_constraint<'a>(
189    rendezvous_key: blake3::Hash,
190    constraint: &ExitConstraint,
191    level: AccountLevel,
192    net_status: &'a NetStatus,
193) -> anyhow::Result<(&'a VerifyingKey, &'a ExitDescriptor)> {
194    let all_exits = net_status.exits.values();
195
196    // Figure out which fields we need to match
197    let mut country_constraint = None;
198    let mut city_constraint = None;
199    let mut hostname_constraint = None;
200
201    match constraint {
202        ExitConstraint::Hostname(host) => hostname_constraint = Some(host.clone()),
203        ExitConstraint::Country(country) => country_constraint = Some(*country),
204        ExitConstraint::CountryCity(country, city) => {
205            country_constraint = Some(*country);
206            city_constraint = Some(city.clone());
207        }
208        ExitConstraint::Auto => {}
209        ExitConstraint::Direct(_) => panic!("should not reach here"),
210    }
211
212    let filtered: Vec<_> = all_exits
213        .filter(|(_, exit, meta)| {
214            let mut pass = match country_constraint {
215                Some(c) => exit.country == c,
216                None => true,
217            };
218            pass &= match &city_constraint {
219                Some(city) => exit.city == *city,
220                None => true,
221            };
222            pass &= match &hostname_constraint {
223                Some(hn) => exit.b2e_listen.ip().to_string() == *hn,
224                None => true,
225            };
226            if matches!(constraint, ExitConstraint::Auto) {
227                pass &= meta.category == ExitCategory::Core;
228            }
229            pass &= meta.allowed_levels.contains(&level);
230            pass
231        })
232        .collect();
233
234    if filtered.is_empty() {
235        anyhow::bail!("no exits match the constraints")
236    }
237
238    // If any matched, we use load-sensitive rendezvous hashing
239    let first = filtered
240        .iter()
241        .min_by_key(|rh| {
242            let (_, exit, _) = **rh;
243            let hash = blake3::keyed_hash(
244                rendezvous_key.as_bytes(),
245                exit.b2e_listen.ip().to_string().as_bytes(),
246            );
247            let hash = &hash.as_bytes()[..];
248            let hash = u64::from_be_bytes(*array_ref![hash, 0, 8]) as f64 / u64::MAX as f64;
249            let weight = (1.0 - (exit.load as f64)).powi(2);
250            let picker = -hash.ln() / weight;
251            OrderedFloat(picker)
252        })
253        .unwrap();
254    Ok((&first.0, &first.1))
255}
256
257fn route_to_dialer(ctx: &AnyCtx<Config>, route: &RouteDescriptor) -> DynDialer {
258    use sillad_native_tls::TlsDialer;
259
260    match route {
261        RouteDescriptor::Tcp(addr) => {
262            smart_vpn_whitelist(ctx, addr.ip());
263            let addr = *addr;
264            TcpDialer { dest_addr: addr }.dynamic()
265        }
266        RouteDescriptor::Sosistab3 { cookie, lower } => {
267            let inner = route_to_dialer(ctx, lower);
268            SosistabDialer {
269                inner,
270                cookie: Cookie::new(cookie),
271            }
272            .dynamic()
273        }
274        RouteDescriptor::Race(inside) => inside
275            .iter()
276            .map(|s| route_to_dialer(ctx, s))
277            .reduce(|a, b| a.race(b).dynamic())
278            .unwrap_or_else(|| FailingDialer.dynamic()),
279        RouteDescriptor::Fallback(a) => a
280            .iter()
281            .map(|s| route_to_dialer(ctx, s))
282            .reduce(|a, b| a.fallback(b).dynamic())
283            .unwrap_or_else(|| FailingDialer.dynamic()),
284        RouteDescriptor::Timeout {
285            milliseconds,
286            lower,
287        } => route_to_dialer(ctx, lower)
288            .timeout(Duration::from_millis(*milliseconds as _))
289            .dynamic(),
290        RouteDescriptor::Delay {
291            milliseconds,
292            lower,
293        } => route_to_dialer(ctx, lower)
294            .delay(Duration::from_millis((*milliseconds).into()))
295            .dynamic(),
296        RouteDescriptor::ConnTest { ping_count, lower } => {
297            let lower = route_to_dialer(ctx, lower);
298            ConnTestDialer {
299                inner: lower,
300                ping_count: *ping_count as _,
301            }
302            .dynamic()
303        }
304
305        RouteDescriptor::Other(_) => FailingDialer.dynamic(),
306        RouteDescriptor::PlainTls { sni_domain, lower } => {
307            let lower = route_to_dialer(ctx, lower);
308            TlsDialer::new(
309                lower,
310                TlsConnector::new()
311                    .use_sni(sni_domain.is_some())
312                    .danger_accept_invalid_certs(true)
313                    .danger_accept_invalid_hostnames(true)
314                    .min_protocol_version(None)
315                    .max_protocol_version(None),
316                sni_domain
317                    .clone()
318                    .unwrap_or_else(|| "example.com".to_string()),
319            )
320            .dynamic()
321        }
322    }
323}
geph5_client/get_dialer.rs

geph5_client/
get_dialer.rs
