msrt 0.1.5

Portable MSRT protocol implementation.
Documentation 
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

//! Tick-driven retransmission.

use crate::engine::{
    EngineConfig, SendFailedEvent, SendFailureReason,
    config::MAX_IN_FLIGHT_PACKETS,
    state::{EngineOutput, EngineState, WriteEvent},
};

use super::inflight::InFlightPacket;

impl EngineState {
    pub(crate) fn tick_retransmit(&mut self, config: &EngineConfig, now_ms: u64) {
        self.clock.update(now_ms);
        self.reassembly.expire(now_ms, config.reassembly_timeout_ms);

        if !self.recovery.should_tick(now_ms) {
            return;
        }

        let mut retransmits = [None; MAX_IN_FLIGHT_PACKETS];
        let mut retransmit_len = 0;
        let mut failures = [None; MAX_IN_FLIGHT_PACKETS];
        let mut failure_len = 0;
        let mut failed_messages = [None; MAX_IN_FLIGHT_PACKETS];
        let mut failed_message_len = 0;

        for packet in self.recovery.packets() {
            if !packet.sent {
                continue;
            }

            if now_ms.saturating_sub(packet.last_sent_ms) < config.retransmit_timeout_ms {
                continue;
            }

            if packet.attempts >= config.max_retransmit_attempts {
                let already_failed = failed_messages[..failed_message_len]
                    .iter()
                    .flatten()
                    .any(|key| *key == (packet.packet_type, packet.message_id));

                if !already_failed && failure_len < failures.len() {
                    failures[failure_len] = Some(*packet);
                    failure_len += 1;
                    failed_messages[failed_message_len] =
                        Some((packet.packet_type, packet.message_id));
                    failed_message_len += 1;
                }
            } else if retransmit_len < retransmits.len() {
                retransmits[retransmit_len] = Some(*packet);
                retransmit_len += 1;
            }
        }

        for packet in failures[..failure_len].iter().flatten() {
            self.log_send_failed_snapshot(config, now_ms, packet);
            self.recovery
                .remove_message(packet.packet_type, packet.message_id);
            let _ = self
                .scheduler
                .push(EngineOutput::SendFailed(SendFailedEvent {
                    packet_type: packet.packet_type,
                    message_id: packet.message_id,
                    reason: SendFailureReason::RetryLimitReached,
                }));
        }

        for packet in retransmits[..retransmit_len].iter().flatten() {
            let message_failed = failed_messages[..failed_message_len]
                .iter()
                .flatten()
                .any(|key| *key == (packet.packet_type, packet.message_id));

            if message_failed {
                continue;
            }

            let _ = self.scheduler.push(EngineOutput::Write(WriteEvent {
                key: packet.key,
                bytes: packet.bytes,
                len: packet.len,
                attempts: packet.attempts.saturating_add(1),
                priority: crate::engine::state::scheduler::WritePriority::Retransmit,
            }));
        }
    }

    #[cfg(feature = "std")]
    fn log_send_failed_snapshot(
        &self,
        config: &EngineConfig,
        now_ms: u64,
        failed: &InFlightPacket,
    ) {
        eprintln!(
            "msrt in_flight send_failed now={} len={} message_len={} ack_pending={} ack_pending_len={} failed_type={:?} failed_message={} failed_index={} attempts={} age_ms={} retry_limit={} rto_ms={}",
            now_ms,
            self.recovery.in_flight_len(),
            self.message.len(),
            self.ack.is_pending(),
            self.ack.pending_len(),
            failed.packet_type,
            failed.message_id.get(),
            failed.key.packet_index.get(),
            failed.attempts,
            now_ms.saturating_sub(failed.last_sent_ms),
            config.max_retransmit_attempts,
            config.retransmit_timeout_ms,
        );
        self.scheduler.log_snapshot(now_ms, self.ack.is_pending());
        self.log_in_flight_packets(now_ms);
    }

    #[cfg(feature = "std")]
    fn log_in_flight_packets(&self, now_ms: u64) {
        for packet in self.recovery.packets() {
            eprintln!(
                "msrt in_flight packet now={} type={:?} msg={} idx={} attempts={} age_ms={} len={} sent={}",
                now_ms,
                packet.packet_type,
                packet.message_id.get(),
                packet.key.packet_index.get(),
                packet.attempts,
                now_ms.saturating_sub(packet.last_sent_ms),
                packet.len,
                packet.sent,
            );
        }
    }

    #[cfg(not(feature = "std"))]
    #[allow(dead_code)]
    fn log_in_flight_packets(&self, _now_ms: u64) {}

    #[cfg(not(feature = "std"))]
    fn log_send_failed_snapshot(
        &self,
        _config: &EngineConfig,
        _now_ms: u64,
        _failed: &InFlightPacket,
    ) {
    }
}