fips-core 0.3.55

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

fn session_receiver_report_can_drive_route_quality(mode: MmpMode, srtt_ms: Option<f64>) -> bool {
    match mode {
        MmpMode::Full => srtt_ms.is_some(),
        MmpMode::Lightweight => true,
        MmpMode::Minimal => false,
    }
}

#[cfg(test)]
mod pending_queue_tests {
    use crate::config::Config;
    use crate::node::{Node, NodeAddr};

    fn make_node() -> Node {
        Node::new(Config::new()).unwrap()
    }

    fn make_node_addr(val: u8) -> NodeAddr {
        let mut bytes = [0u8; 16];
        bytes[0] = val;
        NodeAddr::from_bytes(bytes)
    }

    #[test]
    fn pending_session_queues_drop_oldest_per_destination() {
        let mut node = make_node();
        node.config.node.session.pending_packets_per_dest = 2;

        let tun_dest = make_node_addr(0x41);
        node.queue_pending_packet(tun_dest, vec![1]);
        node.queue_pending_packet(tun_dest, vec![2]);
        node.queue_pending_packet(tun_dest, vec![3]);
        let tun_packets: Vec<Vec<u8>> = node
            .pending_session_traffic
            .tun_packets_for(&tun_dest)
            .expect("tun queue")
            .iter()
            .cloned()
            .collect();
        assert_eq!(tun_packets, vec![vec![2], vec![3]]);

        let endpoint_dest = make_node_addr(0x42);
        node.queue_pending_endpoint_data(endpoint_dest, vec![4]);
        node.queue_pending_endpoint_data(endpoint_dest, vec![5]);
        node.queue_pending_endpoint_data(endpoint_dest, vec![6]);
        let endpoint_payloads: Vec<Vec<u8>> = node
            .pending_session_traffic
            .endpoint_data_for(&endpoint_dest)
            .expect("endpoint queue")
            .iter()
            .map(|payload| payload.as_slice().to_vec())
            .collect();
        assert_eq!(endpoint_payloads, vec![vec![5], vec![6]]);
    }

    #[test]
    fn pending_endpoint_data_queue_owns_drop_oldest_policy() {
        let mut queue = crate::node::PendingEndpointDataQueue::default();
        assert!(!queue.push_bounded(vec![1].into(), 2).dropped_oldest());
        assert!(!queue.push_bounded(vec![2].into(), 2).dropped_oldest());
        assert!(queue.push_bounded(vec![3].into(), 2).dropped_oldest());

        let payloads: Vec<Vec<u8>> = queue
            .iter()
            .map(|payload| payload.as_slice().to_vec())
            .collect();
        assert_eq!(payloads, vec![vec![2], vec![3]]);
    }

    #[test]
    fn pending_tun_packet_queue_owns_drop_oldest_policy() {
        let mut queue = crate::node::PendingTunPacketQueue::default();
        assert!(!queue.push_bounded(vec![1], 2).dropped_oldest());
        assert!(!queue.push_bounded(vec![2], 2).dropped_oldest());
        assert!(queue.push_bounded(vec![3], 2).dropped_oldest());

        let packets: Vec<Vec<u8>> = queue.iter().cloned().collect();
        assert_eq!(packets, vec![vec![2], vec![3]]);
    }

    #[test]
    fn pending_session_traffic_queues_own_destination_admission() {
        let mut queues = crate::node::PendingSessionTrafficQueues::default();
        let tun_dest = NodeAddr::from_bytes([1u8; 16]);
        let rejected_tun_dest = NodeAddr::from_bytes([2u8; 16]);
        let endpoint_dest = NodeAddr::from_bytes([3u8; 16]);
        let rejected_endpoint_dest = NodeAddr::from_bytes([4u8; 16]);

        assert!(
            !queues
                .push_tun_packet(tun_dest, vec![1], 1, 2)
                .destination_dropped()
        );
        assert!(queues.has_traffic_for(&tun_dest));
        assert!(
            queues
                .push_tun_packet(rejected_tun_dest, vec![2], 1, 2)
                .destination_dropped()
        );
        assert!(!queues.has_traffic_for(&rejected_tun_dest));

        assert!(
            !queues
                .push_endpoint_data(endpoint_dest, vec![3], 1, 2)
                .destination_dropped()
        );
        assert!(queues.has_traffic_for(&endpoint_dest));
        assert!(
            queues
                .push_endpoint_data(rejected_endpoint_dest, vec![4], 1, 2)
                .destination_dropped()
        );
        assert!(!queues.has_traffic_for(&rejected_endpoint_dest));

        assert!(
            !queues
                .push_tun_packet(tun_dest, vec![5], 1, 2)
                .dropped_oldest()
        );
        assert!(
            queues
                .push_tun_packet(tun_dest, vec![6], 1, 2)
                .dropped_oldest()
        );

        let packets: Vec<Vec<u8>> = queues
            .tun_packets_for(&tun_dest)
            .expect("accepted TUN queue")
            .iter()
            .cloned()
            .collect();
        assert_eq!(packets, vec![vec![5], vec![6]]);

        let removed = queues.remove_destination(&tun_dest);
        assert_eq!(removed.tun_packets().map(|queue| queue.len()), Some(2));
        assert!(queues.tun_packets_for(&tun_dest).is_none());
        assert!(!queues.has_traffic_for(&tun_dest));
        assert!(queues.endpoint_data_for(&endpoint_dest).is_some());
        assert!(queues.has_traffic_for(&endpoint_dest));
    }

    #[test]
    fn pending_session_traffic_destination_guard_tracks_partial_takes() {
        let mut queues = crate::node::PendingSessionTrafficQueues::default();
        let dest = NodeAddr::from_bytes([9u8; 16]);

        assert!(
            !queues
                .push_tun_packet(dest, vec![1], 8, 2)
                .destination_dropped()
        );
        assert!(
            !queues
                .push_endpoint_data(dest, vec![2], 8, 2)
                .destination_dropped()
        );
        assert!(queues.has_traffic_for(&dest));

        assert!(queues.take_tun_packets(&dest).is_some());
        assert!(
            queues.has_traffic_for(&dest),
            "endpoint payloads should keep the destination guard set"
        );
        assert!(queues.take_endpoint_data(&dest).is_some());
        assert!(
            !queues.has_traffic_for(&dest),
            "guard should clear after the final pending queue is removed"
        );
    }

    #[test]
    fn pending_session_queues_reject_new_destinations_at_cap() {
        let mut node = make_node();
        node.config.node.session.pending_max_destinations = 1;

        let accepted_tun_dest = make_node_addr(0x51);
        let rejected_tun_dest = make_node_addr(0x52);
        node.queue_pending_packet(accepted_tun_dest, vec![1]);
        node.queue_pending_packet(rejected_tun_dest, vec![2]);
        assert!(
            node.pending_session_traffic
                .tun_packets_for(&accepted_tun_dest)
                .is_some()
        );
        assert!(
            node.pending_session_traffic
                .tun_packets_for(&rejected_tun_dest)
                .is_none()
        );

        let accepted_endpoint_dest = make_node_addr(0x61);
        let rejected_endpoint_dest = make_node_addr(0x62);
        node.queue_pending_endpoint_data(accepted_endpoint_dest, vec![3]);
        node.queue_pending_endpoint_data(rejected_endpoint_dest, vec![4]);
        assert!(
            node.pending_session_traffic
                .endpoint_data_for(&accepted_endpoint_dest)
                .is_some()
        );
        assert!(
            node.pending_session_traffic
                .endpoint_data_for(&rejected_endpoint_dest)
                .is_none()
        );
    }
}

/// Mark ECN-CE in an IPv6 packet's Traffic Class field.
///
/// IPv6 Traffic Class occupies bits across bytes 0 and 1:
///   byte[0] bits[3:0] = TC[7:4]
///   byte[1] bits[7:4] = TC[3:0]
/// ECN is TC[1:0]. Only marks CE (0b11) if the packet is ECN-capable
/// (ECT(0) or ECT(1)). Packets with ECN=0b00 (Not-ECT) are never marked
/// per RFC 3168.
///
/// No checksum update needed: IPv6 has no header checksum, and the Traffic
/// Class field is not part of the TCP/UDP pseudo-header.
pub(in crate::node) fn mark_ipv6_ecn_ce(packet: &mut [u8]) {
    if packet.len() < 2 {
        return;
    }
    // Extract 8-bit Traffic Class from IPv6 header bytes 0-1
    let tc = ((packet[0] & 0x0F) << 4) | (packet[1] >> 4);
    let ecn = tc & 0x03;
    // Only mark CE on ECN-capable packets (ECT(0)=0b10 or ECT(1)=0b01)
    if ecn == 0 {
        return;
    }
    // Set both ECN bits to 1 (CE = 0b11)
    let new_tc = tc | 0x03;
    packet[0] = (packet[0] & 0xF0) | (new_tc >> 4);
    packet[1] = (new_tc << 4) | (packet[1] & 0x0F);
}