mirror of
https://github.com/jmcorgan/fips.git
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Johnathan Corgan
56d39f223b
Implement hop-by-hop ECN congestion signaling through the FMP layer, transport-level congestion detection via kernel drop counters, and chaos harness integration for end-to-end validation. FMP/session ECN plumbing: - Thread ce_flag parsed at link layer through dispatch_link_message, handle_session_datagram, handle_session_payload, and handle_encrypted_session_msg to session delivery - Replace hardcoded false in session-layer record_recv() with actual ce_flag, activating ecn_ce_count tracking in session MMP ECN congestion detection and CE relay: - Add EcnConfig (node.ecn.*) with configurable loss_threshold (5%) and etx_threshold (3.0) for transit congestion detection - Add send_encrypted_link_message_with_ce() that ORs FLAG_CE into FMP header flags; original method delegates with ce_flag=false - Compute outgoing_ce = incoming_ce || local congestion on next-hop link, enabling hop-by-hop CE relay through transit nodes IPv6 ECN-CE marking: - Mark ECN-CE (0b11) in IPv6 Traffic Class on received DataPackets before TUN delivery when FMP CE flag is set - Only marks ECN-capable packets (ECT(0)/ECT(1)); Not-ECT packets unchanged per RFC 3168 Transport congestion abstraction and UDP kernel drop detection: - Add TransportCongestion struct to transport layer for transport- agnostic local congestion indicators - Replace tokio::UdpSocket with AsyncFd<socket2::Socket> using libc::recvmsg() with ancillary data parsing - Enable SO_RXQ_OVFL for kernel receive buffer drop counter on every packet, wiring up previously-stubbed UdpStats.kernel_drops - Add TransportDropState for per-transport delta tracking with 1s tick sampling via sample_transport_congestion() - Extend detect_congestion() with transport kernel drop check alongside MMP loss metrics Congestion monitoring and control: - Add CongestionStats (ce_forwarded, ce_received, congestion_detected, kernel_drop_events) to NodeStats with snapshot serialization - Wire counters into forwarding path, session handler, and transport drop sampling with rate-limited warn logging (5s interval) - Expose congestion data in show_routing control query and ecn_ce_count in show_mmp peer entries - Add congestion counters to fipstop routing tab in two-column layout Chaos harness integration: - Add query_routing(), query_transports(), snapshot_all_congestion() to chaos control module - Add congestion/kernel-drop log analysis in logs module - Add congestion-stress scenario: 10-node tree, 1 Mbps bandwidth, 5-10% netem loss, heavy iperf3 traffic - Add IngressConfig for tc ingress policing with per-peer policer filters simulating upstream bandwidth bottlenecks - Add iperf3 JSON result capture to traffic manager for throughput measurement across scenarios - Add ECN A/B test scenarios (ecn-ab-on/off.yaml) with ingress policing and comparison script - Enable TCP ECN negotiation (tcp_ecn=1 sysctl) in container entrypoint for end-to-end CE propagation Tests: - 10 ECN unit/integration tests: mark_ipv6_ecn_ce variants, CE relay chain (3-node propagation), EcnConfig serde roundtrip - 3 transport drop congestion detection unit tests Documentation: - Update fips-mesh-layer.md: replace outdated CE Echo stub with full ECN Congestion Signaling section covering detection logic, CE relay, IPv6 marking, session tracking, and monitoring counters - Update fips-configuration.md: add node.ecn.* parameter table and ecn block in complete reference YAML - Update fips-transport-layer.md: add Congestion Reporting section with TransportCongestion struct, congestion() trait method, and per-transport status; document AsyncFd/recvmsg/SO_RXQ_OVFL in UDP - Update chaos README: add congestion/ECN scenario docs, ingress traffic control, and iperf3 JSON capture sections - Update README.md: add ECN to features list and "What works today"; update transport and tooling entries
101 lines
2.6 KiB
YAML
101 lines
2.6 KiB
YAML
# ECN A/B Test: ECN ENABLED
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#
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# Identical to ecn-ab-off.yaml except ecn.enabled = true.
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# Run both scenarios and compare iperf3 throughput results.
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#
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# Design rationale:
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# - Ingress policing at 1000 kbps: unlike HTB (which paces smoothly),
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# the ingress policer *drops* excess inbound packets at the kernel
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# level. This creates real packet loss visible to the FIPS UDP
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# socket, triggering detect_congestion() via transport_drops.
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# - 10 Mbps egress bandwidth: lets traffic flow freely outbound so
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# that the ingress policer is the bottleneck. Multiple flows
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# competing through bottleneck nodes generate excess traffic that
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# the policer drops.
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# - 10ms link delay: creates realistic RTT and causes TCP to batch
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# packets into bursts, making ingress drops more likely.
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# - 8KB recv_buf_size: small buffer amplifies the effect of bursty
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# arrivals — dropped packets at ingress + buffer overflow trigger
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# detect_congestion() via both MMP loss and transport_drops paths.
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# - tcp_ecn=1 in entrypoint.sh: TCP negotiates ECN so CE marks
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# reach TCP congestion control, enabling proactive backoff.
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# - 4 concurrent sessions with 4 parallel streams: moderate load
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# that creates real contention without overwhelming everything.
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#
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# With ECN enabled, transit nodes detect congestion early and set CE
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# flags, causing TCP to reduce its window proactively. Without ECN,
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# TCP only learns about congestion from packet drops (timeouts/triple
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# dup-ack), which is slower and causes more throughput loss.
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#
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# n01 (root)
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# / \
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# n02 n03
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# / \ \
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# n04 n05 n06
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scenario:
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name: "ecn-ab-on"
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seed: 42
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duration_secs: 120
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topology:
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algorithm: explicit
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num_nodes: 6
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params:
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adjacency:
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- [n01, n02]
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- [n01, n03]
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- [n02, n04]
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- [n02, n05]
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- [n03, n06]
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subnet: "172.20.0.0/24"
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ip_start: 10
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bandwidth:
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enabled: true
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tiers_mbps: [10]
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ingress:
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enabled: true
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tiers_kbps: [1000]
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burst_bytes: 16000
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netem:
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enabled: true
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default_policy:
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delay_ms: [10, 10]
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jitter_ms: [0, 0]
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loss_pct: [0, 0]
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mutation:
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interval_secs: {min: 9999, max: 9999}
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fraction: 0.0
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policies:
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baseline:
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delay_ms: [10, 10]
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loss_pct: [0, 0]
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link_flaps:
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enabled: false
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traffic:
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enabled: true
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max_concurrent: 4
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interval_secs: {min: 3, max: 5}
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duration_secs: {min: 20, max: 30}
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parallel_streams: 4
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node_churn:
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enabled: false
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logging:
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rust_log: "info"
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output_dir: "./sim-results/ecn-ab-on"
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fips_overrides:
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node:
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ecn:
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enabled: true
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transports:
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udp:
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recv_buf_size: 8192
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