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d4b57d49fb
Surface the netem extensions delivered in uBridge feature/tc-netem-ext as GNS3 filter types: rate (tc-style bandwidth string), reorder (needs delay), gemodel (Gilbert-Elliot bursty loss, exclusive with packet_loss), duplicate, seed and limit, plus the delay jitter distribution and the loss/dup correlation parameters. All are kernel-datapath only — the relay's packet-filter registry has no equivalent, so available_filters hides them on relay links, setting one on a created relay link returns 409, and the project-load path drops them with a warning (update_filters runs before the datapath is decided, so it cannot reject there). Validation mirrors the tc grammar: reorder requires delay, gemodel and packet_loss are mutually exclusive, a distribution requires jitter > 0, rate is integer+unit capped at 100gbit. The translation in DockerVM._netem_command_parts emits the frozen grammar order and gates extension keywords on the 'tc capabilities' netem token list (probed once per uBridge process; a plain delay/loss/corrupt/dup filter never probes, keeping old uBridge builds untouched; the correl suffix has no token and gates on 'rate' as the extension-build marker). Reconcile became reset-before-set: the kernel's netem change merges optional attributes (rate, correlation, reorder, corrupt, gemodel, distribution, seed keep their previous value when the new message omits them), so removing a parameter needs an explicit 'tc reset' — the bpf_drop filters are re-added right after in the same flow, so the clsact churn is invisible. The capability check runs before the reset so a failed update leaves the previous qdisc in place. e2e (isolated instance, kernel link): 24/24 — rate 512kbit adds exactly 2x the per-packet serialization to the RTT (45.5 ms for 1400-byte pings), paretonormal jitter + rate-cleared leak check, reorder gap 5, gemodel 50% bursty loss, duplicate, loss 30% correl 50%, seed 42 + limit 5000 visible in the qdisc dump, suspend/resume and node restart keep the filters, relay link rejects rate with 409, teardown leaves no netem. Full unit suite: 1916 passed.