Enabling STP on a bridge whose management rides an in-band VLAN can cut
off that very management - and not only by our own blocking: on this
network the upstream TP-Link Easy Smart switch's "loop prevention"
reacted to our BPDU hellos by blocking ITS port towards us while our
ASIC was all-forwarding, isolating the whole segment until a power
cycle. Recoverable only by going quiet.
Add a commit-confirm watchdog: while STP is enabled, any HTTP request
re-arms a countdown ("stp failsafe <seconds>", default 180, 0 disables);
if management stays silent for the whole window, STP disables itself,
which also stops BPDU TX so a neighbour's loop protection can release
its block. The web UI polls /stp.json every 2 s, so an open browser
naturally keeps the watchdog re-armed. The trip is reported via
/stp.json (fs, fsT) and as a warning on the Spanning Tree page.
Deliberately not conditioned on our own MSTP port states - the incident
above proves the uplink can be dead while every local port forwards.
Also bound the NIC DMA busy-waits (nic_tx_packet, nic_rx_header,
nic_rx_packet): an unbounded spin on SFR_NIC_CTRL freezes the entire
main loop (timers, HTTP, ARP) if the ASIC ever fails to consume a
transfer; give up after ~65k polls and drop the frame instead.
Hardware-verified end to end: with priority 15 against a live RSTP
bridge the uplink died 6 s after "stp on" and the network recovered BY
ITSELF 66 s later (trip at 45 s + neighbour release), fsT=1, LACP and
LAN intact. Telemetry via syslog-to-edge-port host confirmed the full
chain: countdown 44->4, trip, hello TX stopping at the trip.
(cherry picked from commit 1fa9775156fd6d7ebfdda2382f73430b86601230)
Implements the standard 802.1D-2004/802.1w configuration surface:
Bridge: priority (0-15 x4096), hello time, max age, forward delay,
force-version (RSTP v2 / STP-compatible v0 Config BPDUs), tx hold
count (per-port per-second BPDU budget).
Per port: enable, admin edge (forwarding immediately - no listen gap),
auto edge (forwarding after 3 s of BPDU silence; DEFAULT, so
host-facing ports no longer take the full forward delay),
path cost (0=auto/20000), port priority, BPDU guard (port disabled
on BPDU receipt), root guard (never accept a better root on the
port), BPDU filter (no BPDUs in or out).
Engine additions: root max-age expiry (reclaim the tree when the root goes
silent), root path cost accounting (rx cost + root-port cost, advertised in
our BPDUs), loop detection (our own BPDU coming back blocks the port for a
listen period), topology-change counter, approximated per-port roles
(Root/Designated/Alternate) for diagnostics.
CLI: "stp prio|hello|maxage|fwd|txhold|version ..." and
"stp port <n> on|off|edge|cost|prio|guard|filter ..." (stp_parse, delegated
from cmd_parser); all forms accepted by the startup-config validator so the
whole configuration persists. /stp.json now reports config + status; the
Spanning Tree page exposes everything with immediate-apply controls and live
state/role columns (edit-in-flight guard against the 2 s refresh).
8051 memory: the module moves to code BANK2; internal-RAM pressure from
cross-bank calls resolved by xdata loop iterators/scratch, __reentrant on
the small helpers, and moving httpd's header-pointer globals to xdata.
Verified on hardware (SWTGW218AS): defaults land per standard; priority and
hello change live; admin-edge ports (the LACP bond uplinks) keep the LAN at
0% loss THROUGH "stp on"; auto-edge ports forward after 3 s; a port that
heard real BPDUs (a VM bridge behind physical port 6) correctly declined
auto-edge, sat out the full listen period and became Designated; tc counts
promotions; we win the root election at priority 16384 vs 32768.
(cherry picked from commit 09a34dc6acdc81ab9cab0727d2f4a59c68131a3e)
Add a Spanning Tree page: an on/off toggle driving the existing "stp"
command over /cmd, and a live status section fed by a new /stp.json
endpoint - the elected root bridge (priority + MAC), our path cost,
whether we are the root, and the per-port STP state read live from the
ASIC's MSTP register (same 2-bit encoding stp_setup() writes). Ports are
reported by their physical numbers.
Recovered-from: 3132319, 9365c86
d00f