The 600 s clamp was unreachable in practice: the controller's stop
request times out at 240 s (controller/node.py) and the Docker stop
query gets the value +30 s as its HTTP timeout, so anything above 210
would abort upstream first and surface an error while the stop keeps
running server-side. Cap at the derived ceiling and document the chain
in the clamp and the docstring.
Nine fixes from a review of the docker-shm-devices diff:
* GNS3_STOP_TIMEOUT >300 s aborted at the manager's default HTTP timeout
before Docker finished the stop — the stop query now gets a timeout
with a margin over the grace period.
* Overlapping bind targets (GNS3_MASK_UDEV + GNS3_MASK_SYSTEMD on the
same unit, a unit named twice, an extra_configs target equal to a
masked unit) made Docker reject the create with 'Duplicate mount
point' — Mounts are deduplicated by target.
* ExtraConfig.target now carries a pydantic validator (absolute file
path, no '..'), so bad targets 422 at template-save time instead of
failing at node-create time after a multi-GB image pull; directory
forms ('/', '/etc/') are also rejected by the runtime guard instead
of raising IsADirectoryError (raw 500).
* _check_host_readiness skipped every remaining check when one
/proc/sys key was unreadable (mid-loop return) — now continues.
* The base-class GNS3_* env parser strips trailing commas like the
vendor parser, so 'GNS3_MASK_UDEV=1,' composed from a list still
activates.
* Vendor env knobs are re-parsed on every create(), so a PUT to the
node's environment takes effect on the next (re)create.
* The graceful SIGTERM stop is now limited to the explicit user stop
route; delete/update/close/crash-cleanup keep the immediate kill
(those paths force-delete or recreate the container right after).
* An extra_configs target beneath a persisted volume is shadowed by the
volume bind — warn at create time.
The 60 s SIGTERM grace was hardcoded, unlike every other vendor knob
(GNS3_SHM_SIZE, GNS3_DEVICES, GNS3_MASK_UDEV, ...) which rides the
environment line. Parse GNS3_STOP_TIMEOUT=<seconds> (default 60,
clamped to 1-600, invalid values keep the default) and use it in
VendorDockerVM._terminate_container().
DockerVM.stop() terminated containers with an immediate SIGKILL — fine
for init.sh-based containers whose state is persisted beforehand, but a
systemd NOS (Cisco XRd, SR Linux) needs a graceful shutdown and treats
the abrupt kill as an unclean shutdown (exit 137 on every stop).
Extract the final termination into _terminate_container() and override
it in VendorDockerVM: POST /containers/{id}/stop?t=60 sends SIGTERM and
waits for systemd to stop services; Docker itself SIGKILLs the
container once the grace period expires, so no fallback is needed.
Docker's 304 (already stopped) is swallowed.
PortManager.get_free_udp_port had an unguarded find-then-add sequence.
A link allocates both ends concurrently (asyncio.gather in
UDPLink._prepare -> two POST /ports/udp) and FastAPI runs the sync
route handler in a threadpool, so both threads could probe the same
'free' port before either recorded it — handing lport == rport to both
ends. uBridge sets SO_REUSEADDR on UDP NIO sockets, so the double bind
succeeds silently and the kernel delivers everything to the last-bound
socket: one node starves, the other echoes to itself.
Make every TCP/UDP allocate/reserve/release path atomic with an RLock,
and rebuild _link_data in UDPLink._prepare so reset() commits the fresh
port pair instead of re-sending the stale, already-released one.
Regression tests: threaded barrier allocation never returns duplicates
(red on the old code, UDP and TCP); reset() leaves exactly one mirrored
NIO pair per side with lport != rport (red on the old code).
Masking the udev systemd units stopped the daemon's coldplug (host audio
resets), but host USB devices still reconnected on every XRd start. A/B
testing with plain `docker run` isolated the trigger: XRd's own
xr_startup.sh calls udevadm directly (USB license-dongle probing, e.g.
`udevadm trigger --action=add --parent-match=<usb device>`), which
synthesizes uevents into the host kernel from the privileged container --
no udevd required.
GNS3_MASK_UDEV=1 now also binds /dev/null over the udevadm binary
(/bin, /sbin, /usr/bin). Verified with a plain-run experiment: with the
bind, host udev monitor shows zero usb/input/hid/sound events during XRd
boot (only normal docker veth traffic), and XRd itself boots to running
state -- it does not need udevadm under GNS3 (interfaces are pre-created
veths).
The vendor skip-init path (_setup_skip_init_volumes, _fix_permissions) runs
`/gns3/bin/busybox chown` inside the container via docker exec. busybox is
statically linked, and its chown dlopens NSS modules (libnss_*) from the
container; on NOS images whose glibc differs from the host's (e.g. Cisco
XRd) that mismatches and aborts with the glibc assertion
`_dl_call_libc_early_init: sym != NULL` (SIGABRT). The per-file chown loop
then crash-loops, and the resulting core-dump storm -- processed by the
host's systemd-coredump -- cascades into host device rescans, reconnecting
USB / resetting audio / corrupting the journal on every XRd start.
cp/chmod/find/stat don't touch NSS and work fine on busybox, so only chown
is affected. Prefer the container's own coreutils chown
(`command -v chown && chown ...`), falling back to busybox chown only when
the container ships no chown (minimal images, where the glibc matches and
busybox is safe).
A privileged systemd-based NOS container (Cisco XRd boots /usr/sbin/init)
runs systemd-udevd, which on startup coldplugs every device it can reach.
In privileged mode that includes the HOST's USB/input/audio/disk devices,
so every XRd start reconnects USB, mutes audio, and disrupts the host
journal -- highly disruptive on Linux desktops (caught in the act: the
container's udevd was even rescanning the host BTRFS root device).
XRd doesn't need udev (its interfaces are pre-created by GNS3 veth and
mapped via XR_INTERFACES). Add two opt-in env vars, consumed host-side at
container create time in the inherited DockerVM.create (so VendorDockerVM
nodes get it too):
GNS3_MASK_UDEV=1 -> bind /dev/null over the udevd unit, its two
activation sockets, and the coldplug/settle
trigger services
GNS3_MASK_SYSTEMD=u1,u2 -> bind /dev/null over arbitrary units in
/etc/systemd/system/ (comma/semicolon list)
Only injected when set, so ordinary nodes are unaffected.
Add an `extra_configs` field (list of {target, content}) to the docker
node/template/appliance schemas. For each entry GNS3 writes `content` to a
file in the node working directory and bind-mounts it read-only at `target`
inside the container.
This lets a NOS appliance seed its startup config without rebuilding the
image: XRd points XR_FIRST_BOOT_CONFIG at an injected /firstboot.cfg, FRR at
/etc/frr/frr.conf, etc. The bind is a single-file mount applied at create
time, so it works for both the generic init.sh path and vendor nodes that
skip init.sh (console_type=docker_exec). Entries are only injected when
present, so ordinary nodes are unaffected.
The content can't go through `environment` (it is line-delimited, one var per
line), hence a dedicated field -- the same plumbing shape as extra_volumes.
Add a read-only _check_host_readiness() that runs once after the Docker
daemon connection is established. It reads /proc/sys inotify/file-max
limits and /proc/filesystems (for FUSE), and logs a warning with the exact
commands to fix when they are too low for heavy containers -- XRd wants
~4000 inotify instances per node against a stock default of 128.
The server runs unprivileged (only the setuid ubridge helper has root), so
it can only check, not set; the warning tells the admin exactly what to
raise once. Stays silent when the limits are already sufficient.
Heavy NOS containers (e.g. Cisco XRd) need /dev/shm larger than Docker's
64 MB default and host device nodes such as /dev/fuse. Add two opt-in
environment variables, consumed host-side and applied as native Docker
HostConfig keys at create time:
GNS3_SHM_SIZE (MB) -> HostConfig.ShmSize (bytes)
GNS3_DEVICES -> HostConfig.Devices in `docker run --device` syntax
(host[:container[:perm]]; Docker resolves major/minor
from the host node itself)
Native HostConfig (rather than remount/mknod inside init.sh) is used so this
works for vendor NOS nodes that skip init.sh (console_type=docker_exec) --
the path XRd must take, since GNS3's init.sh wrapper crashes XRd's glibc
loader. It applies whether or not init.sh runs, needs no schema/API/UI
change (reuses the `environment` field), and only takes effect when the vars
are set, so ordinary nodes keep default Docker behaviour.
GNS3_-prefixed user env vars stay dropped from the container environment
(only consumed here host-side), keeping GNS3-injected vars safe.
The reconnect-blank-screen bug: when sr_cli exited (quit / idle timeout /
crash) the while-true wrapper restarted it mid-session with no client
attached, so its startup CPR probe (\e[6n) went unanswered and the TUI
degraded/blocked. On reconnect lazy_started=True skipped recreation, so the
client saw a blank screen.
Fix: drop the while-true wrapper. Now when the CLI exits, the exec pty
closes (EOF), the broadcast task ends, and the next client connection
detects the dead upstream via _upstream_alive() and recreates the exec —
with a terminal attached, so CPR is answered. A live exec is reused
(just a Ctrl-L redraw).
_LazyExecTelnetServer is extracted from a closure to module level so the
reconnect/recreate logic is unit-testable. Add 9 tests covering
_upstream_alive states and the recreate-on-death / reuse-if-live /
close-half-dead-writer / no-while-true behaviors.
Full Docker suite (120) passes.
Override _mount_binds in VendorDockerVM: for GNS3_SKIP_INIT containers the
/etc/network volume (GNS3's own network config consumed by init.sh's ifup)
is dead weight — init.sh never runs and the NOS manages its own
interfaces. The override removes the bind, filters /etc/network out of
self._volumes (keeping GNS3_VOLUMES and the bridge/fix passes consistent)
and deletes the host-side skeleton directory created by the base class.
Without GNS3_SKIP_INIT the mount is kept, matching base behaviour.
_persistent_volumes() is removed — the mount override is now the single
filter point.
GNS3_SKIP_INIT containers never run init.sh, so /etc/network (GNS3's own
network config consumed by init.sh's ifup) has no consumer — the NOS
manages its own interfaces. VendorDockerVM._persistent_volumes() filters it
out for both _setup_skip_init_volumes and _fix_permissions, saving one
docker exec per pass. The shared _mount_binds is untouched, and without
GNS3_SKIP_INIT the full volume list is returned so behaviour matches the
base class.
The host-side pass could not work for unprivileged GNS3 processes: the
.gns3_perms marker is created root-owned by the container-side touch, and
chowning root-owned files from the host requires root.
Rewrite VendorDockerVM._fix_permissions to run the busybox
record/chmod/chown script inside the container (as root) on the
/gns3volumes bind-mount targets — they exist for the container's whole
lifetime and do not depend on the mount --bind bridge, so a container
restart can no longer make the fix hit the overlay copy. A
stopped/exited container is skipped (logged) instead of restarted; the
next start's pass fixes ownership.
Replace the container-side _fix_permissions for vendor NOS containers with a
host-side pass that walks the node's project directories directly (they are
the Docker bind-mount sources): records mode:uid:gid into .gns3_perms and
chowns to the GNS3 user. No docker exec, no container restart — the base
implementation restarts an exited container just to chown, and after the
restart the mount --bind bridge is gone so it would fix the overlay copy
instead of the host files.
The pass runs at start (after _setup_skip_init_volumes seeds and bridges the
volumes) so the controller can read project files while the node runs, and
again at stop for files written during runtime.
Update docker-exec-console.md: VendorDockerVM architecture, hook points,
class-selection factory, volume-persistence lifecycle, and new
troubleshooting entries.
Extract the docker_exec console and GNS3_* prototype knobs (SKIP_INIT,
INTERFACE_NAMES, CONSOLE_CMD) from DockerVM into a VendorDockerVM subclass.
DockerVM is restored to its 3.1 baseline plus four small extension hooks
(_prepare_init_and_interface_env, _start_console_server,
_get_container_ifname, _cleanup_console_resources) that are pure
refactorings with zero behaviour change for existing nodes.
VendorDockerVM additionally replicates init.sh's volume persistence
(bind-mount /gns3volumes over the in-container path) via docker exec for
containers that skip init.sh, so vendor NOS config (e.g. /etc/opt/srlinux)
survives node stop/start.
The Docker manager selects VendorDockerVM when console_type == docker_exec;
all other nodes keep using DockerVM unchanged.
The reconcile pass in _ubridge_apply_markers walked the node-wide
_marker_filter_bridges map but compared against `desired`, which only
carries the markers of the NIO being updated. Updating any one link
therefore deleted every other link's markers (and their pcaps) on that
node — a regression from the add-only→reconcile switch. IOU's override
had the same flaw across its ports.
Guard the delete pass with the current bridge (base_node) / IOL location
(IOU) so only markers on the NIO being reconciled can be removed. Added
a regression test that fails without the guard.
The batch marker-def fan-out (PR #2848) routed create/update/delete
marker_definition through memory_only + a batch PUT /nios/batch that
re-applies markers via _ubridge_apply_markers. But _ubridge_apply_markers
was strictly add-only: it skipped any (name, link_id) already in
_marker_filter_bridges, and reset_packet_filters preserves mark filters
(contract). So:
* delete_marker_definition left the deleted marker's filter alive in
uBridge (still matching / signalling / writing pcap) until node restart.
* update_marker_definition (bpf/tag/direction change) never reached
uBridge — the live filter kept the old expression until node restart.
Make _ubridge_apply_markers a real reconcile against the desired
nio.markers:
- installed but no longer desired → delete_packet_filter + unlink pcap
+ unregister
- desired with changed filter field → rebuild (delete + re-add)
- desired with only enabled changed → instant toggle (pcap preserved)
- desired and unchanged → skip
- desired and new → add
Track installed specs in a parallel _marker_specs dict so changes can be
detected. Both base_node and the IOU iol_bridge override are updated.
Added tests for the delete-removed and rebuild-changed-bpf paths.
MarkerManager now logs every 10s how many marker datagrams the UDP sink
processed and the current throughput rate (match/s), so operators can
tell at a glance whether the single sink keeps up with the aggregated
uBridge traffic. Error count is also logged.
1000+ uBridge processes share a single UDP marker.sink endpoint. The
default kernel receive buffer (~208 KB) holds ~1000 datagrams — a
traffic burst can overflow it before the event loop drains them. Grow
it to 8 MB via setsockopt(SO_RCVBUF) so the kernel absorbs bursts
without silent packet loss. UDP is unordered — buffer size does not
affect per-datagram latency, only burst-loss resilience.
The _connect_nio thread-pool optimisation (send_batch_sync) targeted
node-start performance, but start_all already runs at concurrency=3
(by design, to avoid overwhelming the host). It also introduced a
Python 3.13 incompatibility (trsock.setblocking forbidden) that
prevented docker nodes from starting. Since node-start is not the
target of this branch (project-open link creation is), revert to the
simple per-command async _ubridge_send.
The project-open batch NIO dispatch (create_batch_nios) is unaffected —
it never called _connect_nio (nodes aren't started during open).
Python 3.13's asyncio TransportSocket wrapper rejects setblocking(). Dup
the underlying fd via socket.fromfd() into a plain socket that the
executor thread can drive in blocking mode, then detach() after the
batch to avoid closing the transport's fd.
The per-node created / is-closing / Starting-uBridge / Stopping-uBridge
INFO lines flood the log at 1000+ node scale during project open, close,
start-all and stop-all. Demote them to DEBUG (consistent with the
docker_vm lifecycle-log demotion).
At 1000+ nodes the per-node INFO lines flood the log during open /
start-all / stop-all: MAC changed, adapters changed, created, started,
console listen, fix ownership, stopped, paused, removed, adapter created,
NIO removed, capture start/stop, CPU/memory limits, mount resources.
Demote all of these routine per-node/per-adapter lines to DEBUG. Keep
INFO only for genuinely rare/important events: image pull (missing image)
and stale-container cleanup. Warnings unchanged.
- Drop the diagnostic stage-timing logs added during link-create perf
work (nodes / preallocate / prepare / dispatch) now that bottlenecks
are resolved and verified.
- Lower the per-NIO 'added to adapter' log in docker_vm from INFO to
DEBUG — at 5000+ NIOs per project open it floods the log at INFO.
Replace the default asyncio executor (capped at ~32 threads) with a
dedicated ThreadPoolExecutor sized for large-topology parallelism.
When 500 nodes each call _connect_nio, up to 500 OS threads can now
send blocking ubridge commands in parallel — no longer serialised by
either the event loop or a small thread pool.
- ubridge_hypervisor: module-level _ubridge_sync_pool (max_workers=500)
- docker_vm._connect_nio: dispatches to the dedicated pool instead of
the default executor
Replace the 3-5 sequential await _ubridge_send calls in _connect_nio
with a single run_in_executor batch. The batch holds the node-level
asyncio Lock to prevent interleaving with async sends, then uses the
hypervisor's new send_batch_sync method which does blocking socket
sendall/recv inside the thread pool. Different nodes' batches now
run in true OS-thread parallelism rather than serialising through
the asyncio event loop between every command.
- ubridge_hypervisor.send_batch_sync: blocking batch send using
the underlying socket from the asyncio transport, protected by
threading.Lock.
- _connect_nio: builds command list (add_nio_udp, start_capture,
bridge start, reset_packet_filters, add_packet_filter) and
dispatches to the default executor.
Temporary diagnostic instrumentation to measure the wall-clock time of
each ubridge command during NIO addition (add_nio_udp, bridge start,
filters, markers). The logs will reveal whether the 12-NIO/s
throughput stems from ubridge command latency itself or from lock
contention / HTTP overhead outside _connect_nio.
Docker node stop took ~5s every time. The stop API grace period
(params t=5, unchanged since 2015) was always exhausted: the business
process (often an interactive shell) ignores SIGTERM, and GNS3 doesn't
depend on graceful shutdown — _fix_permissions and /gns3volumes already
persist container state before stop() is called.
Use POST /containers/{id}/kill (SIGKILL, zero delay) instead of stop.
The 409 (container already stopped) replaces the previous 304 handling
for the race where the container exits between the state check and the call.
t=5 traced to commit 33edbefa3 (2015-10-14) "Docker cleanup and
improvements" — introduced with no recorded rationale.
The IOU override of _ubridge_apply_markers lacked the incremental guard the generic path has, so on an NIO update it re-added every marker the port already carried. uBridge's add_packet_filter rejects a duplicate filter name (packet_filter.c find_packet_filter), so adding a private marker to an IOU link that already hosted an inherited global-* copy failed with 'Failed to add filter global-...' -- the NIO update re-sends ALL markers on the port (inherited + new private), and the pre-existing one collided.
Add the same (name, link_id) in self._marker_filter_bridges skip as the generic base_node path, so an update only installs markers not already on the port. Mirrors how Dynamips/vpcs/etc. stay idempotent across add + update.
Markers now work on serial links (Cisco HDLC / PPP / Frame Relay / ATM), not just Ethernet. A marker carries a data_link_type (default DLT_EN10MB); at the uBridge boundary it becomes the 'mark ... linktype <dlt>' keyword so the BPF compiles and the pcap is written with the matching link-layer.
- MarkerCreate / MarkerDefinitionCreate gain data_link_type (default DLT_EN10MB). Per-link it is create-only; definitions are updatable (a change re-fans-out).
- base_node._marker_linktype() normalizes the GNS3 DLT name (strip DLT_, uppercase, None for EN10MB). Single source is SerialPort.data_link_types, so Cisco PPP -> PPP_SERIAL (50), matching the capture path -- no second mapping table.
- _ubridge_add_marker_filter (generic) and the IOU marker loop append 'linktype <dlt>'.
- Definition fan-out branches on link_type in inherit_marker: Ethernet is always EN10MB; a serial link uses the definition's WAN encapsulation, or is SKIPPED when none was chosen (an EN10MB pcap on serial is undecodable). One definition covers a mixed topology.
- MCP marker_definition exposes data_link_type (None = not forwarded).
- No uBridge rebuild on a data_link_type change -- only that one marker's filter is swapped (delete + re-add), mirroring a BPF change; reset_packet_filters preserves sibling mark filters.
Requires the uBridge build with 'mark ... linktype' support.
Drop the platform-specific floor (0.9.12 darwin / 0.9.14 others) in
favour of a single 1.2.0 minimum. This server now relies on features
only present in recent uBridge builds: the AF_UNIX control channel
(-U / SO_PEERCRED), the marker (mark) filter, and the brctl-backed
builtin Ethernet Switch. Removes the now-unused sys import left behind
by the dropped darwin branch (target is Linux-only).
128 characters was far beyond any realistic marker label (icmp, arp, tcp-syn)
and would have collided with the pcap filename budget once a tag prefix is
added later. Cap the user-facing name at 32 in both MarkerCreate and
MarkerDefinitionCreate; the compute-side name guard now also rejects names
longer than 48, which covers the `global-{def_name}` inherited form (≤ 39).
Deleting a marker while its node was stopped, then starting the node, recreated
an empty pcap. Root cause: delete_marker_capture removed the uBridge filter and
the pcap file but not the marker spec cached on the port NIO (nio.markers) —
the data source _ubridge_apply_markers reads on node start. The stale spec
reinstalled the marker when uBridge came up.
This was a regression from switching stop_marker off update() (which re-sent
the NIO and implicitly refreshed nio.markers) to the fine-grained
node.delete(/markers/{name}) path.
Fix: make the delete port-aware so the compute can locate the NIO. The DELETE
marker route becomes /adapters/{a}/ports/{p}/markers/{name} across all six
node types; the handler resolves the NIO via get_nio and passes it to
delete_marker_capture, which now pops the marker from nio.markers. get_nio
works regardless of uBridge state, so the stopped-node case is covered. The
controller's stop_marker targets the capture side's adapter/port.
_ubridge_apply_markers now installs only markers not already on the bridge
(uBridge's reset_packet_filters preserves mark filters), so an NIO update no
longer re-adds — and reopens — sibling markers' pcaps. _stop_ubridge clears
_marker_filter_bridges so a node restart re-installs everything (the map would
otherwise keep stale entries pointing at a fresh, empty uBridge).
Deleting or updating a marker no longer triggers a full NIO reapply
(reset_packet_filters + re-add), which closed/reopened every sibling
marker's pcap via uBridge. Instead operate on single filters:
- stop_marker: bridge delete_packet_filter + unlink the pcap (works with
the node stopped; filter removal is skipped, the file is still deleted).
- update_marker: bpf/tag/direction → rebuild just that filter (delete + add);
enabled → instant toggle; color/highlight_duration → stored only.
- compute delete_marker_capture / rebuild_marker_filter + per-node routes
(DELETE /markers/{name}, PUT /markers/{name}/rebuild) + MarkerRebuild schema.
IOU overrides _ubridge_delete_marker_filter for iol_bridge; rebuild reuses
the already-overridden add/delete/set, so IOU needs no rebuild override.
The _marker_filter_bridges dict was keyed by marker name alone, so when one
node hosted the same filter name on several links (IUOL-BRIDGE per node with
many bays/units, or a multi-interface router), successive apply calls
overwrote earlier entries. pause_marker_definition then toggled only the last
recorded bridge/location — other copies stayed active and kept emitting.
Key by (name, link_id) so each copy is independent, and iterate all matching
entries in _ubridge_set_marker_filter_state (both generic bridge and IOU
iol_bridge override). Toggle route existence checks also iterate matching
names. Tests updated.
_ubridge_set_marker_filter_state raised "Marker X is not installed on this
node" when the capture node wasn't running — the name->bridge map is only
populated during _ubridge_apply_markers, which runs when the node is up. The
error was noise: the controller's enabled-only short-circuit catches it and
falls back, and the controller-layer enabled is authoritative (honoured when
the node starts and applies the marker). Treat a missing entry as a no-op
instead of raising.
Wire gns3-server to uBridge's real-time marker controls (contract
../ubridge/doc/gns3server-integration.md §3.2), in three layers:
A. enabled reaches uBridge — _markers_for_node no longer drops disabled
markers controller-side; it carries `enabled` in the NIO spec. apply
installs every marker then issues `enable_packet_filter … off` for the
disabled ones (base_node bridge / iou iol_bridge; old-ubridge errors
downgrade to a warning so a toggle can't break link create).
B. instant per-filter toggle — apply records name→bridge so a new
`_ubridge_set_marker_filter_state` can flip a running filter with
`enable_packet_filter on|off` (iou overrides for iol_bridge + bay/unit).
Each marker-capable node type gains PUT /markers/{name}; update_marker
short-circuits to it when only `enabled` changes (no NIO rebuild, no pcap
flush), falling back to reset+reapply if the route is unavailable.
C. global pause/resume — `_ubridge_marker_pause/resume` send `marker pause`
/ `marker resume` direct to the hypervisor (pause stops signal+pcap,
resume instant, sink retained). Six node-type routes add POST
/markers/pause|resume; project.pause_all/resume_all_markers fan out to
each capture node (deduped, best-effort); REST exposes
POST /projects/{id}/markers/pause|resume.
Toggling enabled and pause/resume are now both instant — only marker create
or a bpf change still go through reset+reapply.
