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.
Switch-to-switch links were the last shape left on the relay: the switch
fast path works by absorbing the *peer's* anchor, and a switch has none —
its ports are its own bridge, and a kernel interface belongs to exactly
one bridge, so two bridges cannot be joined by enslaving anything.
Join them with a veth pair instead: one end per bridge, each side
enslaving its own end and applying its own port mode to it — an access
port on one side and a trunk on the other behaves like the real cable it
models. uBridge's docker create_veth/delete_veth (the primitive every
Docker adapter is already born from) creates and destroys the pair; the
names derive from the link id (utils.kernel_anchor.kernel_cascade_names),
so each side computes its own end and the names survive a restart.
The pair belongs to the link, and the two ends are wired by two
independent uBridge processes — the project-open batch drives different
nodes concurrently — so the protocol is order-free: both sides create the
pair when their own end is missing (one create wins; the loser's failure
is re-checked against the kernel and "the pair is there" is not an
error), and either side's teardown destroys it (deleting one veth end
takes the other with it, so both converge on the same gone pair and the
second delif answers ENOENT). A pre-existing end — this switch restarted,
or a leftover from a previous life of the link id — is reused rather than
recreated, because the other end may still be a live port of the peer
switch; a stale tc qdisc is all a reused end can carry.
No new wire format was needed: a cascade is an anchor NIO on both ends,
the absorbed-anchor case plus the peer end's name. That also corrects the
filter routing — the single-sided rule exists because an absorbed anchor
is one interface, while a cascade has one per switch, so impairments go
to both ends like any other kernel link.
Tests: the wire format, the eligibility flip and the both-ends re-push on
node start (controller); the naming contract (utils); the switch-side
lifecycle — create, reuse, lost create race, delete destroys the pair
(compute routes).
Drive-by: the relay filter test's compute mock carried no awaitable
`put`, so tests/controller/test_kernel_datapath_link.py failed when run
alone while an argument-less full run passed; callers now get one.
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.
The brctl Ethernet switch runs a per-port uBridge relay, so it can host
the mark filter and packet filters like any uBridge-backed node. Add
ethernet_switch to _MARKER_CAPABLE_TYPES and _get_filter_node, narrow the
UDPLink.update() NIO-PUT skip down to the Dynamips-hosted ethernet_hub,
and expose the matching compute endpoints: PUT nio (filter/marker
reapply) plus the per-marker toggle/pause/resume/delete/rebuild routes.
The ethernet_hub keeps its exclusion: its routes still wire into the
Dynamips hub, which has no uBridge of its own.
Replace psutil.net_if_addrs() scan with a deterministic name derived from
the switch's node UUID: gns3 + first 6 hex chars (10 chars, fits kernel
IFNAMSIZ limit of 15). Taps: <bridge>-<port> (12-13 chars).
Crash recovery: brctl delete the bridge first (best-effort), then create
fresh. Stale bridges from abnormal gns3server shutdown are automatically
reclaimed on the next start — no EEXIST or leaked interfaces.
Remove _free_iface helper and psutil import (no longer needed).
brctl create leaves the bridge administratively DOWN. Add link set up
so the bridge actually forwards frames between enslaved ports.
Also record Docker iptables FORWARD DROP pitfall in project memory.
Replace the builtin EthernetSwitch stub with a Linux kernel bridge backed
by uBridge's brctl module. Each switch node creates one kernel bridge
(gns3br{N}) with VLAN filtering; each port is a persistent TAP enslaved to
the bridge, relayed by a per-port uBridge bridge (nio_tap <-> nio_udp).
- Access/dot1q/qinq port modes translated to brctl vlan primitives
- Compute router repointed from Dynamips to Builtin manager
- Tests updated: 21 router-level tests + 215 surrounding tests pass
- Real-kernel e2e verified: access 100 PVID untagged, dot1q trunk
VIDs 1-4094 + native 1, qinq 802.1ad proto + 200 PVID
Ethertype 0x9100/0x9200 handling and port-count guard relaxation are
deferred pending resolution.
