The persistent-TAP lifecycle — probe, sweep, create, register, delete —
was implemented four times, once per node type, and the copies had drifted
(probe mechanism, _tap_datapath reset, keep-vs-recreate policy). The
mechanical half moves into KernelDatapathMixin:
- _probe_persistent_taps(probe_name): the scratch-TAP probe, returning the
refusal for the caller's own warning (QEMU, Dynamips);
- _create_anchor_taps(ports, set_owner, keep_existing): sweep + create +
optional ownership handover + carrier down + registry, with the ports
enumerated by the node type and named through the new _tap_name hook;
- _delete_anchor_taps(): the suppressed tap sweep + per-link bridge
cleanup + registry clear.
Each node type keeps what its fd holder dictates: the release step before
the tap sweep (the QEMU process, the IOL bridge, the hypervisor's NIO
bindings, the container port bridges), its probe policy, and its registry
lifetime. QEMU's now-unconditional registry clear aligns it with the other
three; everything else is behavior-preserving.
Compute:
- Track the anchor that owns uBridge's single AF_PACKET capture slot: a
second kernel port's capture is refused with a clear error (its flag
rolled back), a failed start no longer wedges the port, and only the
owning port's stop issues the process-wide `capture stop_kernel`
(docker/qemu/iou/dynamips/switch, via the mixin's slot helpers).
- Unwind failed starts instead of leaking uBridge and the anchor TAPs:
QEMU's stop body runs under try/finally, QEMU and IOU start the datapath
inside the launch try, Dynamips undoes a half-attached port (the retry
used to be short-circuited into a silent black hole), and Docker deletes
the veth pair when the namespace move fails.
- Restore the relay filter guard on IOU (kernel-only filters raise
NodeError, an uncompilable BPF line degrades to a warning), validate the
eBPF/quota/window/bpf filter shapes before touching the bridge (short or
non-numeric values surfaced as 500s after partial state), and refuse a
second NIO on an occupied Docker/QEMU port (the guard IOU and Dynamips
already had).
- Probe fixes: `_probe_bridge_tap` survives a failing uBridge start, and
the probe caches key on ctime too, so a chmod/setcap remedy re-probes.
Controller:
- Parse GNS3_UNIX_SOCKET_NIO like the compute does (line-anchored, truthy
value) and mirror the compute's class selection in kernel_anchor_type.
- Read partial capability reports defensively; make BridgeNIO.bridge
required-but-nullable so an omitted key is a 422 rather than a KeyError.
- Strip the packet_loss correlation slot even when it is zero: the relay
filter takes exactly one argument and rejected `packet_loss 10 0`.
Ethernet switch: skip ports whose absorbed anchor does not exist yet (the
join is deferred by design) and roll the ports_mapping back when the VLAN
reconcile fails, so a retry still diffs against the old mapping.
Agent: reject device config entries without a device_name instead of
silently dropping them (a malformed batch used to execute partially while
reporting success).
Also split the netem builder to clear C901 and drop the two per-file ruff
ignores the PR had added, keeping the remove-only policy.
The rebase onto 65c858d45 brought upstream's UP032 enforcement; the
conflict resolution kept this branch's semantics on the overlapping
lines, so their .format() calls needed the conversion afterwards
(ruff check --fix, 41 sites) plus the formatter's rewrap (7 files).
Replicates the CI recipe locally: pip check, ruff check/format, mypy
2.3.1 (clean, 434 files), unit suite 2216 passed.
Upstream's mypy pass narrowed the filter copy to UDPNIO only (the
Ethernet/TAP members of the union have no filters field). BridgeNIO —
the kernel-datapath NIO — carries filters too, so on an IOU kernel link
every PUT of a link's filters cleared them and applied nothing: netem
never landed on the anchor (e2e test_iou_kernel_datapath caught it).
Narrow to (UDPNIO, BridgeNIO): still avoids attribute access on the
models without the field, keeps both filter-carrying types.
The rebase onto upstream 3.1 (mypy + ruff I001/F401 waves) left the tree
short of the newly enforced baselines in three ways:
* contextlib / UbridgeError imports dropped as false duplicates during
conflict resolution left NameErrors in iou_vm and qemu_vm (F821);
the Dynamips router grabbed the compute-level NIOTAP instead of the
hypervisor one, breaking TAP anchoring (test failure).
* unused imports (KERNEL_UNSUPPORTED_FILTERS, UbridgeError, List) and
unsorted blocks left behind where the stack's later commits moved the
last usage elsewhere — ruff I001/F401/RUF022 now enforce these.
* mypy, now baseline-free: cache dict annotations in tc_probe, the
locators candidate list, the resolved-params None branch in the MCP
runner, and validate_bpf_syntax keeps the upstream Dict[str, Any]
return (the strict Optional[str] was wrong for the "valid" bool entry).
The e2e raw-frame probe resolves its compiler via shutil.which (S607)
and zips with strict= (B905); the remaining subprocess call is S603 by
nature and gets a per-file ignore like other test files.
ruff check/format clean, mypy at upstream parity (no new errors),
full unit suite 2167 passed.
A batch carrying the same device twice lost all but the last entry's
commands: the per-device command map kept only the last entry while
result processing iterated every original entry, so each row reported
the last entry's output under its own command list.
c3c78f99a consolidated the merge into the MCP template renderer, but
that only runs when a template is passed — the MCP direct-commands
path and gns3-copilot's direct _run path were left uncovered.
Normalize once in each tool's _run (single point covering all entry
paths, restoring the c42b3a59b coverage) and keep the renderer merge
as boundary normalization. Blocked-command info now also accumulates
across same-device entries instead of last-winning in the per-device
map.
The peer end of an Ethernet switch fast-path link is a NIOBridge with no
bridge of its own (the switch absorbed its anchor into the switch bridge).
Its update reconcile still ran the impairment pass with the empty filter
set the controller routes to that end — and an empty set is a plain
`tc reset` on the shared anchor, silently wiping the netem/cls_bpf/eBPF
the switch had just applied. Any link update did it (filters, markers,
suspend, capture start/stop), and the outcome depended on the link's
endpoint order: UdpLink.update() PUTs node1 then node2, so with the
switch first its apply ran first and the peer's reset ran last (API
green, data plane unimpaired), while with the peer first the reset ran
first and the filter survived. That order dependence is also why the
shipped e2e never caught it — it only created peer-first links.
Ownership is now explicit: only the end that owns the anchor's tc state
applies the impairment reconcile (_owns_anchor_impairments — a NIOBridge
with `bridge is None` is a passive carrier, the same idiom the
bridge-delete path already used). Markers, capture and the suspend
carrier still apply on both ends: markers reconcile per process, so
neither end can strip the other's, and the carrier converges by
agreement.
Red/green: two new docker unit tests fail on the unfixed tree with
`tc reset "<anchor>"` and pass after; the switch e2e also creates one
link switch-first and asserts the netem qdisc and the RTT hold under
that order (failed with the wipe, passes with the fix). Full unit suite
2110 passed; the switch e2e file passed end to end (378s).
A correctness read-through of the five delivered datapath documents, plus
the two code comments that carried the same stale vocabulary.
Datapath selection: the VendorDockerVM selector is `console_type=docker_exec`
alone (`GNS3_SKIP_INIT` and friends are behavior knobs of the chosen class);
the cross-compute and anchor-less fallbacks are named for what they are; the
Ethernet-switch endpoint is the documented exception to the anchoring rule,
and the IOL runner container is called out as the Docker node that does not
anchor on a veth.
Filter vocabulary: the stateful eBPF program evaluates four modes
(nth → quota → window → flow), GNS3 exposes three of them, and window_drop
joins the kernel-only list; the correl suffixes gate on the `rate` token as
the extension-build marker.
group_fwd_mask: the 0xfffd port mask is applied inside uBridge's `brctl addif`
itself, not as a separate command — the link-creation sequences and the
operation tables no longer show an arrow the server never sends. Same class
of fix for `link set up` on the IOL anchor (addif already brought it up; the
command only pushes a suspended anchor back down) and for the QEMU carrier
replication (QMP `set_link`, gated by `replicate_network_connection_state`).
Lifecycles and stop orders re-worded around the invariant rather than the
node type: the fd holder must release before the devices are deleted, which
is QEMU's process-first order, IOU's uBridge-first order and Dynamips'
hypervisor-NIO-first order. Deferred wiring for a stopped endpoint is
documented as the common path it is, and the Dynamips "stop is not a close"
note now says what recovery from a dead hypervisor actually requires.
Dynamips specifics: a c7200 needs an adapter in slot 1 (slot 0 is the fixed
I/O slot), the tap-fd direction is stated correctly (writes inject into the
kernel, reads return what the kernel transmits), and the anchor registry is
name-keyed against the controller's port matrix by convention, not derivation.
IOL port bridge naming: `bridge{bay}` on unit 0, `bridge{bay}_{unit}`
elsewhere; the leg swap happens on link delete/re-create or a datapath
switch, while suspend is an in-place NIO update and a project reopen is a
fresh build.
Verified and Roadmap sections: the in-repo e2e suite is distinguished from
the isolated-instance development harness (IOU), assertions are stated with
their bounds and capability gates, and the roadmap entries collapse into the
one remaining project — VXLAN/GENEVE for cross-compute links.
Code comments: `flow` added to the documented mode order in the eBPF apply
path, and the `nio_bridge` module docstring corrected on which filter types
run on the kernel datapath (bpf via cls_bpf, frequency_drop/quota/window_drop
via the eBPF classifier — neither is relay-only any more).
docker create_veth hardens only its FIRST end (the Docker shape: host
anchor plus a container leg that keeps its L3 life). A cascade end is
that second, unhardened end whenever the peer switch's create won the
race, and the kernel gives it an IPv6 link-local — a silent L3 identity
on the switch fabric (ubridge-l2-anchor-spec §E). Each switch now
hardens its OWN end with 'link l2only <end> on' once the pair exists,
whatever branch brought it there (fresh create, lost race, reuse);
idempotent, and best-effort with a warning on a uBridge without the
command.
The compute-side backstop of the controller's duplicate-port guard
(keep-port-links + live-port bind made the controller guard reliable;
this is the layer under it). IOU and Dynamips bound the adapter NIO
before the uBridge/hypervisor attach: a failed attach left the port's
binding replaced — the link that still owned the port lost its handle
and its host state leaked (the IOU EBUSY incident's 8 orphan TAPs).
Dynamips was worse: its wiring idempotence check silently skipped the
attach on a second binding and rebound only the bookkeeping. A port
that already carries an NIO is now refused, and both types bind the
NIO only after the wiring succeeded.
Link.delete cleared the port link through the port object stored at
add_node time; a node update since then rebuilt the port list, so that
object was stale and the live port kept its link — the next link on the
port was refused with "Port is already used". Masked until now by the
older rebuild bug (c2d68a65d): links never survived a rebuild, so the
guard never fired and the stale clear never mattered.
Node._list_ports() rebuilds every Port object, and it runs on each node
update — including every compute node.updated notification (a node
reporting started is one). The links are unaffected by that rebuild, but
the fresh port objects started out with link=None, so after any node
update the "Port is already used" guard in Link.add_node stopped matching:
a second link on an occupied port reached the compute, where the port's
NIO was replaced before the attach failed on the already-bound anchor,
leaving the link half-torn-down (on IOU, deleting the project afterwards
left the node's anchor TAPs and a per-link bridge on the host).
Carry the link back-references over by (adapter_number, port_number),
first match wins, mirroring get_port; a port that still exists keeps its
link. Regression tests pin both the reference (test_node) and the guard
(test_link: the duplicate link is refused after a node update).
The spec's B table grows its fifth row: bridge add_nio_tap mints a
transient TAP when the name is free and hardens it at creation, while an
attach to an existing device (possibly a user-owned TAP with addresses)
is left untouched. The rule paragraph spells out attach-is-not-a-creation.
Delivery: uBridge fb72758, closing the gap the new e2e assertions found
(live: the switch's gns3*-0 relay TAP carried fe80::). The server issues
no link l2only of its own -- the switch call site now documents that the
TAP is minted-and-hardened by add_nio_tap, and the ESW feature doc
describes the uBridge-side close instead of a server workaround.
_is_unix_socket_docker no longer excludes the IOL runner marker: those
containers anchor on persistent TAPs now (compute side), so they
graduate through _kernel_endpoint_ready's gate instead — both
ubridge_bridge_tap (the swappable leg) and ubridge_tap (the tap module)
strict True, an unreported capability keeping the link on the relay
where it always works. The generic GNS3_UNIX_SOCKET_NIO exclusion keeps
its shape (an IOL runner environment wins the compute's class
selection, so the exclusion must not fire when both markers are set).
The switch fast path names an IOL runner peer's anchor through
kernel_anchor_type — the iol_docker key, never the gv veth namespace.
The 307d676cb regression tests move with the semantics: the capability
matrix replaces the unconditional relay, and the switch-path test also
asserts the gx naming. Its original concern stands — a compute that
cannot serve the anchor lifecycle must never be handed a kernel link
(the switch's deferred join would make it a silent dead cable).
IOL runner containers (IOLDockerVM, GNS3_IOL_RUNNER) had no kernel
datapath: their guest leg is the runner's AF_UNIX socket pairs, so every
link rode the uBridge relay. Their Ethernet bays now own persistent TAP
anchors (gx names, the iol_docker key of the shared naming contract —
born at node start like IOU's, before any link, so the switch fast
path's deferred join can never miss them), and the per-port bridge's
topology leg swaps between UDP (relay) and the anchor (kernel link)
through the frozen stop -> delete -> add -> start contract — the unix
binding never re-binds across a swap.
- iol_docker_vm: KernelDatapathMixin hooks, the anchor lifecycle
(_prepare_tap_datapath at _start_ubridge: probe ubridge_bridge_tap +
ubridge_tap, sweep leftover, tap create born down), the kernel attach
(ensure-then-add — tap create is strictly create-only, IFF_TUN_EXCL,
so the ensure checks /sys/class/net first: an unconditional create
answers EBUSY on the device the start loop just made), the release
(port bridge stop + delete_nio_tap before the shared teardown) and the
stop order the fd holders dictate (port bridges first, then tap
delete, then the per-link bridges — all before the hypervisor stops).
- vendor_docker_vm: the port-bridge creation factored into
_ensure_unix_port_bridge (idempotent on the registered name), keeping
the NIOBridge rejection for the generic unix-socket containers.
- docker_vm: the three _kernel_veths lookups go through the
_kernel_host_ifc hook — behavior-identical for DockerVM, and it is
what lets the subclass route without overriding the binding methods.
- kernel_anchor: the iol_docker key (gx) and kernel_anchor_type, the
controller-side mapping for naming an IOL runner's anchor on the
switch fast path (the marker check stays inline: this module sits
below everything and must not import the controller package).
