fips-core 0.3.78

Reusable FIPS mesh, endpoint, transport, and protocol library
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
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
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
impl Node {
    /// Handle a locally-delivered session datagram payload.
    ///
    /// Called from `handle_session_datagram()` when `dest_addr == self.node_addr()`.
    /// Dispatches based on the 4-byte FSP common prefix:
    ///
    /// - Phase 0x1 → SessionSetup (handshake msg1)
    /// - Phase 0x2 → SessionAck (handshake msg2)
    /// - Phase 0x3 → SessionMsg3 (XK handshake msg3)
    /// - Phase 0x0 + U flag → plaintext error signal (CoordsRequired/PathBroken)
    /// - Phase 0x0 + !U → packet_mover2 authenticated receive only
    pub(in crate::node) async fn handle_session_payload(
        &mut self,
        delivery: LocalSessionPayload<'_>,
    ) {
        let src_addr = *delivery.source_addr();
        let payload = delivery.payload();
        let prefix = match FspCommonPrefix::parse(payload) {
            Some(p) => p,
            None => {
                debug!(
                    len = payload.len(),
                    "Session payload too short for FSP prefix"
                );
                return;
            }
        };

        let inner = &payload[FSP_COMMON_PREFIX_SIZE..];

        match prefix.phase {
            FSP_PHASE_MSG1 => {
                self.handle_session_setup(&src_addr, inner).await;
            }
            FSP_PHASE_MSG2 => {
                self.handle_session_ack(&src_addr, inner).await;
            }
            FSP_PHASE_MSG3 => {
                self.handle_session_msg3(&src_addr, inner).await;
            }
            FSP_PHASE_ESTABLISHED if prefix.is_unencrypted() => {
                // Plaintext error signals: read msg_type from first byte after prefix
                if inner.is_empty() {
                    debug!("Empty plaintext error signal");
                    return;
                }
                let error_type = inner[0];
                let error_body = &inner[1..];
                match SessionMessageType::from_byte(error_type) {
                    Some(SessionMessageType::CoordsRequired) => {
                        self.handle_coords_required(error_body).await;
                    }
                    Some(SessionMessageType::PathBroken) => {
                        self.handle_path_broken(error_body).await;
                    }
                    Some(SessionMessageType::MtuExceeded) => {
                        self.handle_mtu_exceeded(error_body).await;
                    }
                    _ => {
                        debug!(error_type, "Unknown plaintext error signal type");
                    }
                }
            }
            FSP_PHASE_ESTABLISHED => {
                debug!(
                    src = %self.peer_display_name(&src_addr),
                    "Dropping established FSP payload outside packet_mover2 receive path"
                );
                return;
            }
            _ => {
                debug!(phase = prefix.phase, "Unknown FSP phase");
            }
        }
    }

    pub(in crate::node) async fn process_packet_mover2_authenticated_sessions(
        &mut self,
        ingress_batch: Vec<crate::packet_mover2::PacketMover2FspSessionIngress>,
    ) -> usize {
        let mut processed = 0usize;
        let mut endpoint_deliveries = Vec::new();
        let mut endpoint_commit = SessionReceiveBatchCommit::default();

        for ingress in ingress_batch {
            let Some(dispatch) = self.packet_mover2_authenticated_session_dispatch(ingress) else {
                continue;
            };

            if dispatch.is_endpoint_data() {
                let deliveries =
                    dispatch.dispatch_endpoint_data_batched(self, &mut endpoint_commit);
                processed = processed.saturating_add(deliveries.len());
                endpoint_deliveries.extend(deliveries);
                continue;
            }

            self.flush_packet_mover2_endpoint_session_batch(
                &mut endpoint_deliveries,
                &mut endpoint_commit,
            )
            .await;
            dispatch.dispatch(self).await;
            processed = processed.saturating_add(1);
        }

        self.flush_packet_mover2_endpoint_session_batch(&mut endpoint_deliveries, &mut endpoint_commit)
            .await;
        processed
    }

    pub(in crate::node) async fn process_packet_mover2_compact_endpoint_data(
        &mut self,
        endpoint_bulks: Vec<crate::packet_mover2::PacketMover2EndpointDataBulk>,
    ) -> usize {
        if endpoint_bulks.is_empty() {
            return 0;
        }
        let message_count = endpoint_bulks
            .iter()
            .map(crate::packet_mover2::PacketMover2EndpointDataBulk::len)
            .sum::<usize>();
        let direct_packet_runs = endpoint_bulks
            .iter()
            .map(crate::packet_mover2::PacketMover2EndpointDataBulk::direct_packet_run_count)
            .sum::<usize>();
        let direct_sink = if direct_packet_runs > 0 {
            match self.packet_mover2_endpoint_direct_sink() {
                Some(sink) => Some(sink),
                None => {
                    debug!(
                        messages = message_count,
                        "Dropping PM2 endpoint-data bulk without direct sink"
                    );
                    return 0;
                }
            }
        } else {
            None
        };

        let mut endpoint_commit = SessionReceiveBatchCommit::default();
        let mut direct_packet_batches = Vec::with_capacity(endpoint_bulks.len());
        for bulk in endpoint_bulks {
            for run in bulk.commit_runs() {
                let commit = run.commit();
                let source_addr = commit.source_addr();
                let previous_hop_addr = commit.previous_hop_addr();
                if self.promote_packet_mover2_authenticated_pending_fsp_epoch(
                    &source_addr,
                    commit.received_k_bit(),
                ) {
                    debug!(
                        src = %self.peer_display_name(&source_addr),
                        received_k_bit = commit.received_k_bit(),
                        run_len = run.len(),
                        "FSP rekey cutover complete after PM2 compact endpoint-data receive commit"
                    );
                }
                self.learn_reverse_route(source_addr, previous_hop_addr);
                endpoint_commit.push_receive_completion(SessionReceiveCompletion {
                    source_addr,
                    previous_hop_addr,
                    direct_path: commit.direct_path(),
                });
            }
            if bulk.direct_packet_run_count() > 0 {
                direct_packet_batches.push(bulk.into_direct_packet_batch());
            }
        }

        let pending_flush_destinations = endpoint_commit.finish(self);
        let count = direct_packet_batches
            .iter()
            .map(crate::node::FipsEndpointDirectPacketBatch::len)
            .sum::<usize>();
        if count > 0 {
            let direct_sink = direct_sink.expect("direct sink is required when packet runs remain");
            for batch in direct_packet_batches {
                if direct_sink.deliver_direct_packet_batch(batch).is_err() {
                    crate::perf_profile::record_event_count(
                        crate::perf_profile::Event::EndpointEventBulkDropped,
                        count as u64,
                    );
                    break;
                }
            }
        }
        for dest_addr in pending_flush_destinations {
            self.flush_pending_packets(&dest_addr).await;
        }
        message_count
    }

    fn packet_mover2_endpoint_direct_sink(&self) -> Option<crate::node::EndpointDirectSink> {
        self.endpoint_events
            .sender()
            .and_then(|sender| sender.direct_sink().cloned())
    }

    fn packet_mover2_authenticated_session_dispatch(
        &mut self,
        ingress: crate::packet_mover2::PacketMover2FspSessionIngress,
    ) -> Option<AuthenticatedSessionDispatch> {
        let received_k_bit = ingress.received_k_bit();
        let (
            source_addr,
            source_peer,
            previous_hop_addr,
            ce_flag,
            _activity_tick,
            timestamp_ms,
            msg_type,
            inner_flags,
            plaintext,
        ) = ingress.into_parts();
        let body_len = plaintext
            .len()
            .saturating_sub(crate::node::session_wire::FSP_INNER_HEADER_SIZE);

        debug!(
            src = %self.peer_display_name(&source_addr),
            previous_hop = %self.peer_display_name(&previous_hop_addr),
            msg_type,
            msg_kind = ?SessionMessageType::from_byte(msg_type),
            plaintext_len = plaintext.len(),
            body_len,
            endpoint_data = msg_type == SessionMessageType::EndpointData.to_byte()
                || msg_type == SessionMessageType::EndpointDataBulk.to_byte(),
            "Dispatching packet mover2 authenticated session"
        );

        if self.promote_packet_mover2_authenticated_pending_fsp_epoch(
            &source_addr,
            received_k_bit,
        ) {
            debug!(
                src = %self.peer_display_name(&source_addr),
                received_k_bit,
                "FSP rekey cutover complete after PM2 authenticated pending epoch"
            );
        }

        let message =
            AuthenticatedSessionMessage::new(source_peer, plaintext, msg_type, inner_flags, timestamp_ms);
        Some(AuthenticatedSessionDispatch::new(
            source_addr,
            previous_hop_addr,
            ce_flag,
            message,
        ))
    }

    async fn flush_packet_mover2_endpoint_session_batch(
        &mut self,
        endpoint_deliveries: &mut Vec<EndpointDataDelivery>,
        endpoint_commit: &mut SessionReceiveBatchCommit,
    ) {
        if endpoint_deliveries.is_empty()
            && endpoint_commit.previous_hops.is_empty()
            && endpoint_commit.direct_sources.is_empty()
            && endpoint_commit.retry_peers.is_empty()
            && endpoint_commit.pending_flush_sources.is_empty()
        {
            return;
        }

        let pending_flush_destinations = std::mem::take(endpoint_commit).finish(self);
        if !endpoint_deliveries.is_empty() {
            self.deliver_endpoint_data_batch(std::mem::take(endpoint_deliveries));
        }
        for dest_addr in pending_flush_destinations {
            self.flush_pending_packets(&dest_addr).await;
        }
    }

    pub(in crate::node) fn record_authenticated_fmp_receive_facts(
        &mut self,
        fmp: crate::node::AuthenticatedFmpReceiveFacts<'_>,
        previous_hop: Option<&NodeAddr>,
    ) {
        let now = Instant::now();
        let source_addr = fmp.source_node_addr();
        let arrived_from_source = previous_hop.is_none_or(|hop| hop == source_addr);
        let path_bookkeeping_allowed = self.authenticated_packet_path_allows_bookkeeping(
            source_addr,
            fmp.transport_id,
            fmp.remote_addr,
            fmp.packet_timestamp_ms,
        ) && arrived_from_source;
        if path_bookkeeping_allowed {
            let _ = self.packet_mover2.record_authenticated_fmp_mmp_receive(
                source_addr,
                fmp.fmp_counter,
                fmp.inner_timestamp_ms,
                fmp.packet_len,
                fmp.fmp_flags & FLAG_CE != 0,
                fmp.fmp_flags & FLAG_SP != 0,
                now,
            );
        }
        let bookkeeping = self.peers.record_authenticated_fmp_receive(
            source_addr,
            fmp.transport_id,
            &fmp.remote_addr,
            fmp.packet_timestamp_ms,
            fmp.packet_len,
            fmp.fmp_counter,
            fmp.inner_timestamp_ms,
            fmp.fmp_flags & FLAG_CE != 0,
            fmp.fmp_flags & FLAG_SP != 0,
            now,
            path_bookkeeping_allowed,
        );
        if let Some(update) = bookkeeping {
            if update.path_bookkeeping_recorded {
                self.clear_retry_unless_direct_refresh_needed(source_addr);
            }
            if update.address_changed {
                self.sync_packet_mover2_fmp_owner(source_addr);
            }
        }
    }

    pub(in crate::node) async fn handle_packet_mover2_fsp_decrypt_failure(
        &mut self,
        source_addr: NodeAddr,
        counter: u64,
        received_k_bit: bool,
    ) -> bool {
        self.handle_reported_fsp_decrypt_failure(
            source_addr,
            counter,
            received_k_bit,
            "packet_mover2",
        )
        .await
    }

    async fn handle_reported_fsp_decrypt_failure(
        &mut self,
        src_addr: NodeAddr,
        counter: u64,
        received_k_bit: bool,
        source: &'static str,
    ) -> bool {
        let now_ms = Self::now_ms();
        let owner_activity = self.packet_mover2.fsp_owner_activity(&src_addr);
        let authenticated_inbound_age_ms =
            owner_activity.and_then(|activity| activity.last_rx_age_ms(now_ms));
        if owner_activity.is_some_and(|activity| {
            activity.should_ignore_stale_epoch_decrypt_failure(received_k_bit)
        }) {
            trace!(
                src = %self.peer_display_name(&src_addr),
                counter,
                source,
                "Ignoring FSP AEAD failure from stale previous key epoch during PM2-owned drain"
            );
            return true;
        }
        let Some(entry) = self.sessions.get(&src_addr) else {
            debug!(
                src = %self.peer_display_name(&src_addr),
                counter,
                source,
                "FSP AEAD failure for unknown session"
            );
            return false;
        };
        let entry_can_recover = entry.is_established()
            && !entry.has_rekey_in_progress()
            && entry.pending_new_session().is_none();
        let Some(consecutive) = self.packet_mover2.record_fsp_decrypt_failure(src_addr) else {
            debug!(
                src = %self.peer_display_name(&src_addr),
                counter,
                source,
                "FSP AEAD failure for missing packet_mover2 owner"
            );
            return false;
        };
        let recover_session =
            should_start_decrypt_failure_rekey(entry_can_recover, consecutive, authenticated_inbound_age_ms);
        debug!(
            src = %self.peer_display_name(&src_addr),
            counter,
            consecutive_failures = consecutive,
            source,
            "FSP AEAD decryption failed"
        );
        if recover_session {
            warn!(
                peer = %self.peer_display_name(&src_addr),
                consecutive_failures = consecutive,
                "Session AEAD failures exceeded threshold; starting recovery rekey"
            );
            if !self.initiate_session_rekey(&src_addr).await {
                debug!(
                    peer = %self.peer_display_name(&src_addr),
                    source,
                    "Failed to start recovery rekey after FSP decrypt-failure threshold"
                );
            }
        }
        true
    }

    async fn handle_mesh_traversal_offer(&mut self, src_addr: &NodeAddr, body: &[u8]) {
        let Some(bootstrap) = self.nostr_discovery.clone() else {
            trace!(
                src = %self.peer_display_name(src_addr),
                "Ignoring mesh traversal offer without Nostr discovery runtime"
            );
            return;
        };
        if self.configured_peer(src_addr).is_none() {
            debug!(
                src = %self.peer_display_name(src_addr),
                "Ignoring mesh traversal offer from unconfigured peer"
            );
            return;
        }
        let Some(sender_npub) = self.npub_for_node_addr(src_addr) else {
            debug!(
                src = %self.peer_display_name(src_addr),
                "Ignoring mesh traversal offer without known sender npub"
            );
            return;
        };
        let offer = match serde_json::from_slice::<TraversalOffer>(body) {
            Ok(offer) => offer,
            Err(error) => {
                debug!(
                    src = %self.peer_display_name(src_addr),
                    error = %error,
                    "Malformed mesh traversal offer"
                );
                return;
            }
        };
        if offer.sender_npub != sender_npub {
            debug!(
                src = %self.peer_display_name(src_addr),
                claimed = %offer.sender_npub,
                actual = %sender_npub,
                "Ignoring mesh traversal offer with sender mismatch"
            );
            return;
        }
        bootstrap
            .receive_mesh_traversal_offer(offer, sender_npub)
            .await;
    }

    async fn handle_mesh_traversal_answer(&mut self, src_addr: &NodeAddr, body: &[u8]) {
        let Some(bootstrap) = self.nostr_discovery.clone() else {
            trace!(
                src = %self.peer_display_name(src_addr),
                "Ignoring mesh traversal answer without Nostr discovery runtime"
            );
            return;
        };
        if self.configured_peer(src_addr).is_none() {
            debug!(
                src = %self.peer_display_name(src_addr),
                "Ignoring mesh traversal answer from unconfigured peer"
            );
            return;
        }
        let Some(sender_npub) = self.npub_for_node_addr(src_addr) else {
            debug!(
                src = %self.peer_display_name(src_addr),
                "Ignoring mesh traversal answer without known sender npub"
            );
            return;
        };
        let answer = match serde_json::from_slice::<TraversalAnswer>(body) {
            Ok(answer) => answer,
            Err(error) => {
                debug!(
                    src = %self.peer_display_name(src_addr),
                    error = %error,
                    "Malformed mesh traversal answer"
                );
                return;
            }
        };
        if answer.sender_npub != sender_npub {
            debug!(
                src = %self.peer_display_name(src_addr),
                claimed = %answer.sender_npub,
                actual = %sender_npub,
                "Ignoring mesh traversal answer with sender mismatch"
            );
            return;
        }
        bootstrap
            .receive_mesh_traversal_answer(answer, sender_npub)
            .await;
    }

}