Two real iol-xe containers (Cisco CML iol-runner images, real IOS-XE on
the telnet console) against an isolated instance, the real uBridge with
the swappable bridge TAP leg:
* kernel link reports kernel_datapath; anchors exist from node start
and the per-link bridge enslaves exactly the two of them;
* real ICMP crosses the [unix <-> tap] port-bridge relay; delay 100
lands as netem on both anchors with the measured RTT growing >= 150 ms
and returning < 50 ms when cleared;
* suspend admin-downs the anchor and kills the traffic; resume
restores; AF_PACKET capture writes a real pcap;
* link delete/re-create swaps the port leg out and back in with the
ping returning; node stop leaves no gx devices and a start recreates
the whole wiring from the NIO; project delete cleans everything;
* the relay control on a relay-configured instance keeps the link off
the kernel and still pings (anchors may exist idle — the same
semantics as QEMU's and Dynamips' anchors: the server flag decides
attachment, not anchor birth).
Harness: create_iol_router (the appliance's template properties),
docker_images, iol_anchor_name, stage_iol_base_config (the shipped
iol-xe-base.txt copied into the isolated instance's configs dir — the
GNS3_IOL_STARTUP_CONFIG lookup path), boot_wait(straight_prompt=True)
for images that boot from NVRAM straight into the CLI with no 'Press
RETURN' sentinel, and GNS3_E2E_DEBUG=1 to run the isolated instance
with debug logging (the uBridge command stream lands in server.log —
how the ensure-anchor EBUSY was pinned down).
The Ethernet switch's kernel fast path: instead of a link crossing the
switch's per-port uBridge relay, the switch absorbs the peer's anchor into
its own kernel bridge. The peer's interface (Docker veth host end, QEMU
TAP, IOU port TAP, Dynamips port TAP) becomes the switch port, and frames
cross anchor -> switch bridge -> switch ports entirely in the kernel.
Wire format: the switch end receives nio_anchor ('join this interface to
my own bridge' — the mirror of nio_bridge), the peer end nio_bridge with a
null bridge ('your anchor is bridged elsewhere': carrier, markers and
impairments only — never bridge membership, and never a bridge delete, on
an interface this node does not own). Anchor names come from the shared
naming contract (utils.kernel_anchor), a pure function of node type, id,
adapter and port — the controller computes the peer's anchor while the
node may be stopped, which is what makes links to stopped nodes wireable.
Stopped peers defer the join; after any node of a link starts
(UDPLink.node_started) the controller re-pushes the switch NIO, and the
switch completes — or repairs, when a peer restart replaced its interface
under the same name — the join against the kernel's actual membership
instead of assuming it.
VLAN changes now edit membership in place: only the ports whose mode/VLAN
actually changed are touched, each losing exactly the previous mode's
entries the new mode does not want (the dot1q admits-all entry is one
range operation in both directions), and no port ever leaves the bridge to
change its VLANs. This replaces the old 'reset by re-enslaving' shortcut
(delif+addif on every wired port, added when the ports were the switch's
own TAPs): on absorbed anchors, re-enslaving an interface owned by another
node is where live testing watched links die — anchors occasionally lost
their bridge membership right after a ports_mapping update (later updates
then failed with delif EINVAL), reproducibly with qemu, IOU and Dynamips
peers and never with Docker's veths.
Eligibility: the switch side needs no capability of its own (its bridge
exists by construction); the peer must be able to anchor. Switch-to-switch
cascades stay on the relay — a kernel interface belongs to one bridge, and
joining two bridges needs a veth pair, deferred.
Verified live on a real server: qemu peers through four VLAN cycles with
both anchors enslaved throughout; a mixed switch (2 IOU + 2 Dynamips, four
kernel ports); Docker peers with real ICMP isolating and recovering (with
both anchors still enslaved); VPCS relay ports likewise in place.
Live e2e verification moves into the repository instead of being rewritten
as a throwaway script every time: tests/e2e/ carries a shared harness (REST
client, isolated-instance lifecycle, a deliberately dumb IOS console
driver, host-side kernel inspection: bridge membership, tap admin state,
tc qdiscs) and each node type adds only its scenario module. The e2e marker
plus 'addopts = -m "not e2e"' keeps these privileged, image-dependent
tests out of normal runs; they are opt-in: pytest -m e2e tests/e2e -s.
The harness targets an existing server via GNS3_E2E_URL or starts an
isolated instance (own config dir — DB and paths follow it — on a free
port) and deletes its project afterwards (GNS3_E2E_KEEP=1 keeps it on
failure).
The first scenario drives two real c7200 routers on a real IOS image
through the REST API and the consoles: the kernel link is created while the
routers are stopped (deferred wiring), the per-link kernel bridge enslaves
exactly the two anchors, real ICMP crosses it, delay 100 shows netem on
both anchors and grows the RTT (~200 ms), suspend kills the traffic on an
admin-down anchor, capture writes a pcap of ICMP records, a serial link
between the same routers stays on the relay and still pings, delete/
re-create and stop/start leave the wiring consistent, and deleting the
project removes every anchor and bridge. A negative control runs the same
topology on an isolated relay-configured instance (no per-link bridge,
nothing enslaved, still pings).
