1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
/* This file is part of DarkFi (https://dark.fi)
 *
 * Copyright (C) 2020-2024 Dyne.org foundation
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

//! Manual connections session. Manages the creation of manual sessions.
//! Used to create a manual session and to stop and start the session.
//!
//! A manual session is a type of outbound session in which we attempt
//! connection to a predefined set of peers. Manual sessions loop forever
//! continually trying to connect to a given peer, and sleep
//! `outbound_connect_timeout` times between each attempt.
//!
//! Class consists of a weak pointer to the p2p interface and a vector of
//! outbound connection slots. Using a weak pointer to p2p allows us to
//! avoid circular dependencies. The vector of slots is wrapped in a mutex
//! lock. This is switched on every time we instantiate a connection slot
//! and insures that no other part of the program uses the slots at the
//! same time.

use std::sync::{Arc, Weak};

use async_trait::async_trait;
use futures::stream::{FuturesUnordered, StreamExt};
use log::{debug, error, info, warn};
use smol::lock::{Mutex as AsyncMutex, RwLock as AsyncRwLock};
use url::Url;

use super::{
    super::{
        connector::Connector,
        p2p::{P2p, P2pPtr},
    },
    Session, SessionBitFlag, SESSION_MANUAL,
};
use crate::{
    net::{hosts::HostState, settings::Settings},
    system::{sleep, StoppableTask, StoppableTaskPtr},
    Error, Result,
};

pub type ManualSessionPtr = Arc<ManualSession>;

/// Defines manual connections session.
pub struct ManualSession {
    pub(in crate::net) p2p: Weak<P2p>,
    slots: AsyncMutex<Vec<Arc<Slot>>>,
}

impl ManualSession {
    /// Create a new manual session.
    pub fn new(p2p: Weak<P2p>) -> ManualSessionPtr {
        Arc::new(Self { p2p, slots: AsyncMutex::new(Vec::new()) })
    }

    pub(crate) async fn start(self: Arc<Self>) {
        // Activate mutex lock on connection slots.
        let mut slots = self.slots.lock().await;

        let mut futures = FuturesUnordered::new();

        let self_ = Arc::downgrade(&self);

        // Initialize a slot for each configured peer.
        // Connections will be started by not yet activated.
        for peer in &self.p2p().settings().read().await.peers {
            let slot = Slot::new(self_.clone(), peer.clone(), self.p2p().settings());
            futures.push(slot.clone().start());
            slots.push(slot);
        }

        while (futures.next().await).is_some() {}
    }

    /// Stops the manual session.
    pub async fn stop(&self) {
        let slots = &*self.slots.lock().await;
        let mut futures = FuturesUnordered::new();

        for slot in slots {
            futures.push(slot.stop());
        }

        while (futures.next().await).is_some() {}
    }
}

#[async_trait]
impl Session for ManualSession {
    fn p2p(&self) -> P2pPtr {
        self.p2p.upgrade().unwrap()
    }

    fn type_id(&self) -> SessionBitFlag {
        SESSION_MANUAL
    }
}

struct Slot {
    addr: Url,
    process: StoppableTaskPtr,
    session: Weak<ManualSession>,
    connector: Connector,
}

impl Slot {
    fn new(
        session: Weak<ManualSession>,
        addr: Url,
        settings: Arc<AsyncRwLock<Settings>>,
    ) -> Arc<Self> {
        Arc::new(Self {
            addr,
            process: StoppableTask::new(),
            session: session.clone(),
            connector: Connector::new(settings, session),
        })
    }

    async fn start(self: Arc<Self>) {
        let ex = self.p2p().executor();

        self.process.clone().start(
            self.run(),
            |res| async {
                match res {
                    Ok(()) | Err(Error::NetworkServiceStopped) => {}
                    Err(e) => error!("net::manual_session {}", e),
                }
            },
            Error::NetworkServiceStopped,
            ex,
        );
    }

    /// Attempts a connection on the associated Connector object.
    async fn run(self: Arc<Self>) -> Result<()> {
        let ex = self.p2p().executor();

        let mut attempts = 0;
        loop {
            attempts += 1;

            info!(
                target: "net::manual_session",
                "[P2P] Connecting to manual outbound [{}] (attempt #{})",
                self.addr, attempts
            );

            let settings = self.p2p().settings().read_arc().await;
            let seeds = settings.seeds.clone();
            let outbound_connect_timeout = settings.outbound_connect_timeout;
            drop(settings);

            // Do not establish a connection to a host that is also configured as a seed.
            // This indicates a user misconfiguration.
            if seeds.contains(&self.addr) {
                error!(
                    target: "net::manual_session",
                    "[P2P] Suspending manual connection to seed [{}]", self.addr.clone(),
                );
                return Ok(())
            }

            if let Err(e) = self.p2p().hosts().try_register(self.addr.clone(), HostState::Connect) {
                debug!(target: "net::manual_session",
                    "Cannot connect to manual={}, err={}", &self.addr, e);

                sleep(outbound_connect_timeout).await;

                continue
            }

            match self.connector.connect(&self.addr).await {
                Ok((url, channel)) => {
                    info!(
                        target: "net::manual_session",
                        "[P2P] Manual outbound connected [{}]", url,
                    );

                    let stop_sub = channel.subscribe_stop().await?;

                    // Channel is now connected but not yet setup

                    // Register the new channel
                    match self.session().register_channel(channel.clone(), ex.clone()).await {
                        Ok(()) => {
                            // Wait for channel to close
                            stop_sub.receive().await;

                            info!(
                                target: "net::manual_session",
                                "[P2P] Manual outbound disconnected [{}]", url,
                            );
                        }
                        Err(e) => {
                            self.handle_failure(e, &url);
                        }
                    }
                }
                Err(e) => {
                    self.handle_failure(e, &self.addr);
                }
            }

            info!(
                target: "net::manual_session",
                "[P2P] Waiting {} seconds until next manual outbound connection attempt [{}]",
                outbound_connect_timeout, self.addr,
            );

            sleep(outbound_connect_timeout).await;
        }
    }

    fn handle_failure(&self, error: Error, addr: &Url) {
        warn!(
            target: "net::manual_session",
            "[P2P] Unable to connect to manual outbound [{}]: {}",
            self.addr, error,
        );

        // Free up this addr for future operations.
        self.p2p().hosts().unregister(addr);
    }

    fn session(&self) -> ManualSessionPtr {
        self.session.upgrade().unwrap()
    }

    fn p2p(&self) -> P2pPtr {
        self.session().p2p()
    }

    async fn stop(&self) {
        self.connector.stop();
        self.process.stop().await;
    }
}