test nic state link api

backend/src/api/network_api.py

@@ -1,11 +1,15 @@
 """Network inspection and bridge management endpoints."""
 
-from typing import List, Optional
+from typing import Any, Dict, List, Optional
 
 from fastapi import APIRouter, Depends, HTTPException
 from pydantic import BaseModel, Field
 from pyroute2 import IPRoute, NDB
 
+from src.config import settings
+from src.utilities.bridge_link_state_manager import bridge_link_state_manager
+from src.utilities.interface_bridge_helpers import get_bridge_ports_once
+
 router = APIRouter()
 
 ip: IPRoute | None = None
@@ -79,6 +83,41 @@ class BridgeRemoveRequest(BaseModel):
     name: str
 
 
+class BridgeLinkStateEnableRequest(BaseModel):
+    """Payload for enabling bridge member link-state propagation."""
+
+    poll_interval_seconds: float = Field(
+        settings.bridge_link_state_poll_interval_seconds,
+        gt=0,
+        description="Polling interval for member link-state checks.",
+    )
+
+
+class BridgeMemberLinkStateInfo(BaseModel):
+    """Current link-state snapshot for one bridge member."""
+
+    ifname: str = Field(..., description="Interface name.")
+    admin_up: Optional[bool] = Field(None, description="Whether the interface has IFF_UP set.")
+    carrier_up: Optional[bool] = Field(None, description="Whether the interface currently reports carrier.")
+    operstate: Optional[str] = Field(None, description="Kernel operational state string.")
+    link_ready: bool = Field(..., description="Whether the member currently looks usable for forwarding.")
+    suppressed: bool = Field(..., description="Whether the watcher administratively suppressed this member.")
+
+
+class BridgeLinkStateWatcherStatus(BaseModel):
+    """Status for one bridge link-state propagation watcher."""
+
+    bridge: str = Field(..., description="Bridge interface name.")
+    active: bool = Field(..., description="Whether the watcher thread is currently active.")
+    poll_interval_seconds: Optional[float] = Field(None, description="Watcher polling interval.")
+    last_poll_ts: Optional[float] = Field(None, description="Unix timestamp of the last poll.")
+    last_error: Optional[str] = Field(None, description="Most recent watcher error, if any.")
+    last_action: Optional[str] = Field(None, description="Most recent propagation action.")
+    suppressed_members: List[str] = Field(default_factory=list, description="Members currently forced down by the watcher.")
+    members: Dict[str, BridgeMemberLinkStateInfo] = Field(default_factory=dict, description="Per-member link-state snapshot.")
+    message: Optional[str] = Field(None, description="Optional informational message.")
+
+
 def init_network_api() -> None:
     """Initialize lazy pyroute2 clients."""
     global ip, ndb
@@ -91,6 +130,7 @@ def init_network_api() -> None:
 def shutdown_network_api() -> None:
     """Close pyroute2 clients if they were initialized."""
     global ip, ndb
+    bridge_link_state_manager.stop()
     if ip:
         ip.close()
         ip = None
@@ -167,6 +207,11 @@ def bridge_exists(name: str, ip_route: IPRoute) -> bool:
     return bool(ip_route.link_lookup(ifname=name))
 
 
+def _watcher_status_response(payload: dict[str, Any]) -> BridgeLinkStateWatcherStatus:
+    """Convert an internal watcher status dictionary to the API response model."""
+    return BridgeLinkStateWatcherStatus.model_validate(payload)
+
+
 @router.get("/interfaces", response_model=List[InterfaceInfo])
 def get_interfaces(ip: IPRoute = Depends(get_iproute)) -> List[InterfaceInfo]:
     """List host interfaces with addresses and decoded flags."""
@@ -346,3 +391,64 @@ def remove_bridge(req: BridgeRemoveRequest, ip: IPRoute = Depends(get_iproute))
         "status": "ok",
         "deleted": req.name,
     }
+
+
+@router.get("/bridge/link-state-watchers", response_model=List[BridgeLinkStateWatcherStatus])
+def list_bridge_link_state_watchers() -> List[BridgeLinkStateWatcherStatus]:
+    """List all bridge member link-state propagation watchers."""
+    return [_watcher_status_response(status) for status in bridge_link_state_manager.list_statuses()]
+
+
+@router.get("/bridge/{bridge_name}/link-state-watcher", response_model=BridgeLinkStateWatcherStatus)
+def get_bridge_link_state_watcher(
+    bridge_name: str,
+    ip: IPRoute = Depends(get_iproute),
+) -> BridgeLinkStateWatcherStatus:
+    """Return the watcher status for one bridge."""
+    if not bridge_exists(bridge_name, ip):
+        raise HTTPException(status_code=404, detail=f"Bridge {bridge_name} not found")
+
+    status = bridge_link_state_manager.get_status(bridge_name)
+    if status is None:
+        return BridgeLinkStateWatcherStatus(
+            bridge=bridge_name,
+            active=False,
+            message="watcher not enabled",
+        )
+    return _watcher_status_response(status)
+
+
+@router.post("/bridge/{bridge_name}/link-state-watcher/enable", response_model=BridgeLinkStateWatcherStatus)
+def enable_bridge_link_state_watcher(
+    bridge_name: str,
+    req: BridgeLinkStateEnableRequest,
+    ip: IPRoute = Depends(get_iproute),
+) -> BridgeLinkStateWatcherStatus:
+    """Enable member link-state propagation for a bridge."""
+    if not bridge_exists(bridge_name, ip):
+        raise HTTPException(status_code=404, detail=f"Bridge {bridge_name} not found")
+
+    members = get_bridge_ports_once(bridge_name)
+    if len(members) < 2:
+        raise HTTPException(
+            status_code=400,
+            detail=f"Bridge {bridge_name} must have at least two member interfaces",
+        )
+
+    status = bridge_link_state_manager.enable(
+        bridge_name=bridge_name,
+        poll_interval_seconds=req.poll_interval_seconds,
+    )
+    return _watcher_status_response(status)
+
+
+@router.post("/bridge/{bridge_name}/link-state-watcher/disable", response_model=BridgeLinkStateWatcherStatus)
+def disable_bridge_link_state_watcher(
+    bridge_name: str,
+    ip: IPRoute = Depends(get_iproute),
+) -> BridgeLinkStateWatcherStatus:
+    """Disable member link-state propagation for a bridge."""
+    if not bridge_exists(bridge_name, ip):
+        raise HTTPException(status_code=404, detail=f"Bridge {bridge_name} not found")
+
+    return _watcher_status_response(bridge_link_state_manager.disable(bridge_name))

backend/src/config.py

@@ -52,6 +52,8 @@ class BackendSettings:
     sniffer_buffer_drain_interval_seconds: float
     sniffer_thread_join_timeout_seconds: float
     bridge_bpf_build_dir: str
+    bridge_link_state_poll_interval_seconds: float
+    bridge_link_state_thread_join_timeout_seconds: float
     telemetry_process_stop_timeout_seconds: float
     telemetry_reader_join_timeout_seconds: float
     tshark_enabled: bool
@@ -86,6 +88,14 @@ def load_settings() -> BackendSettings:
         sniffer_buffer_drain_interval_seconds=_env_float("BACKEND_SNIFFER_BUFFER_DRAIN_INTERVAL_SECONDS", 5.0),
         sniffer_thread_join_timeout_seconds=_env_float("BACKEND_SNIFFER_THREAD_JOIN_TIMEOUT_SECONDS", 2.0),
         bridge_bpf_build_dir=_env_str("BACKEND_BRIDGE_BPF_BUILD_DIR", "/tmp/mitm-bpf"),
+        bridge_link_state_poll_interval_seconds=_env_float(
+            "BACKEND_BRIDGE_LINK_STATE_POLL_INTERVAL_SECONDS",
+            0.25,
+        ),
+        bridge_link_state_thread_join_timeout_seconds=_env_float(
+            "BACKEND_BRIDGE_LINK_STATE_THREAD_JOIN_TIMEOUT_SECONDS",
+            2.0,
+        ),
         telemetry_process_stop_timeout_seconds=_env_float("BACKEND_TELEMETRY_PROCESS_STOP_TIMEOUT_SECONDS", 3.0),
         telemetry_reader_join_timeout_seconds=_env_float("BACKEND_TELEMETRY_READER_JOIN_TIMEOUT_SECONDS", 2.0),
         tshark_enabled=_env_bool("BACKEND_TSHARK_ENABLED", True),

backend/src/utilities/bridge_link_state_manager.py

@@ -0,0 +1,289 @@
+"""Background watcher that propagates bridge member link failures to sibling ports."""
+
+from __future__ import annotations
+
+import logging
+import threading
+import time
+from dataclasses import dataclass
+from typing import Any, Dict, Optional
+
+from pyroute2 import IPRoute
+
+from src.config import settings
+from src.utilities.interface_bridge_helpers import (
+    check_interface_exists,
+    get_bridge_ports_once,
+    read_interface_admin_up,
+    read_interface_carrier,
+    read_interface_operstate,
+)
+
+logger = logging.getLogger("bridge_link_state_manager")
+
+
+@dataclass
+class MemberLinkState:
+    """Current sysfs-derived state for one bridge member."""
+
+    ifname: str
+    admin_up: Optional[bool]
+    carrier_up: Optional[bool]
+    operstate: Optional[str]
+
+    @property
+    def link_ready(self) -> bool:
+        """Return whether the member currently looks healthy enough to forward."""
+        if self.admin_up is not True:
+            return False
+        if self.carrier_up is False:
+            return False
+        if self.operstate in {"down", "lowerlayerdown", "notpresent"}:
+            return False
+        return True
+
+    def to_dict(self, suppressed: bool = False) -> Dict[str, Any]:
+        """Serialize member state for API responses."""
+        return {
+            "ifname": self.ifname,
+            "admin_up": self.admin_up,
+            "carrier_up": self.carrier_up,
+            "operstate": self.operstate,
+            "link_ready": self.link_ready,
+            "suppressed": suppressed,
+        }
+
+
+class BridgeLinkStateWatcher:
+    """Watch one bridge and mirror member failures to the other bridge members."""
+
+    def __init__(self, bridge_name: str, poll_interval_seconds: float) -> None:
+        self.bridge_name = bridge_name
+        self.poll_interval_seconds = poll_interval_seconds
+        self._stop_event = threading.Event()
+        self._lock = threading.Lock()
+        self._thread = threading.Thread(
+            target=self._run,
+            daemon=True,
+            name=f"bridge-link-state-{bridge_name}",
+        )
+        self._running = False
+        self._suppressed_members: dict[str, bool] = {}
+        self._last_poll_ts: Optional[float] = None
+        self._last_error: Optional[str] = None
+        self._last_action: Optional[str] = None
+        self._member_states: dict[str, MemberLinkState] = {}
+
+    def start(self) -> None:
+        """Start the watcher thread."""
+        with self._lock:
+            if self._running:
+                return
+            self._running = True
+        self._thread.start()
+
+    def stop(self) -> None:
+        """Stop the watcher and restore interfaces that were suppressed by it."""
+        self._stop_event.set()
+        if self._thread.is_alive():
+            self._thread.join(timeout=settings.bridge_link_state_thread_join_timeout_seconds)
+
+        try:
+            self._restore_suppressed_members(reason="watcher_stopped")
+        except Exception:
+            logger.exception("Failed to restore suppressed members for bridge=%s", self.bridge_name)
+
+        with self._lock:
+            self._running = False
+
+    def status(self) -> dict[str, Any]:
+        """Return a JSON-serializable snapshot of the watcher state."""
+        with self._lock:
+            members = {
+                ifname: state.to_dict(suppressed=ifname in self._suppressed_members)
+                for ifname, state in sorted(self._member_states.items())
+            }
+            return {
+                "bridge": self.bridge_name,
+                "active": self._running and self._thread.is_alive() and not self._stop_event.is_set(),
+                "poll_interval_seconds": self.poll_interval_seconds,
+                "last_poll_ts": self._last_poll_ts,
+                "last_error": self._last_error,
+                "last_action": self._last_action,
+                "suppressed_members": sorted(self._suppressed_members),
+                "members": members,
+            }
+
+    def _run(self) -> None:
+        while not self._stop_event.is_set():
+            try:
+                self._poll_once()
+                with self._lock:
+                    self._last_error = None
+            except Exception as exc:
+                logger.exception("Bridge link-state poll failed for bridge=%s", self.bridge_name)
+                with self._lock:
+                    self._last_error = str(exc)
+            self._stop_event.wait(self.poll_interval_seconds)
+
+    def _poll_once(self) -> None:
+        members = [iface for iface in get_bridge_ports_once(self.bridge_name) if check_interface_exists(iface)]
+        states = {iface: self._read_member_state(iface) for iface in members}
+        now = time.time()
+
+        with self._lock:
+            self._last_poll_ts = now
+            self._member_states = states
+            self._suppressed_members = {
+                iface: restore_up
+                for iface, restore_up in self._suppressed_members.items()
+                if iface in states
+            }
+
+        if len(states) < 2:
+            self._restore_suppressed_members(reason="bridge_has_fewer_than_two_members")
+            return
+
+        suppressed_snapshot = set(self._suppressed_members)
+        failing_members = sorted(
+            ifname
+            for ifname, state in states.items()
+            if ifname not in suppressed_snapshot and not state.link_ready
+        )
+
+        if failing_members:
+            self._suppress_other_members(states, failing_members)
+            return
+
+        self._restore_suppressed_members(reason="all_members_recovered")
+
+    def _read_member_state(self, ifname: str) -> MemberLinkState:
+        return MemberLinkState(
+            ifname=ifname,
+            admin_up=read_interface_admin_up(ifname),
+            carrier_up=read_interface_carrier(ifname),
+            operstate=read_interface_operstate(ifname),
+        )
+
+    def _suppress_other_members(self, states: dict[str, MemberLinkState], failing_members: list[str]) -> None:
+        desired_suppressed = set(states) - set(failing_members)
+
+        with self._lock:
+            current_suppressed = dict(self._suppressed_members)
+
+        next_suppressed: dict[str, bool] = {}
+        changed_members: list[str] = []
+
+        for ifname in sorted(desired_suppressed):
+            restore_up = current_suppressed.get(ifname, states[ifname].admin_up is True)
+            if ifname not in current_suppressed and states[ifname].admin_up is True:
+                self._set_interface_admin_state(ifname, target_up=False)
+                changed_members.append(ifname)
+            next_suppressed[ifname] = restore_up
+
+        with self._lock:
+            self._suppressed_members = next_suppressed
+            action = (
+                f"suppressed {changed_members} because failing members={failing_members}"
+                if changed_members
+                else f"holding suppressed members because failing members={failing_members}"
+            )
+            self._last_action = action
+
+    def _restore_suppressed_members(self, reason: str) -> None:
+        with self._lock:
+            suppressed = dict(self._suppressed_members)
+
+        if not suppressed:
+            with self._lock:
+                self._last_action = f"no_restore_needed ({reason})"
+            return
+
+        restored_members: list[str] = []
+        for ifname, restore_up in sorted(suppressed.items()):
+            if not check_interface_exists(ifname):
+                continue
+            if restore_up:
+                self._set_interface_admin_state(ifname, target_up=True)
+                restored_members.append(ifname)
+
+        with self._lock:
+            self._suppressed_members = {}
+            self._last_action = f"restored {restored_members} ({reason})"
+
+    def _set_interface_admin_state(self, ifname: str, target_up: bool) -> None:
+        if not check_interface_exists(ifname):
+            raise RuntimeError(f"Interface {ifname} disappeared while propagating link state")
+
+        state_name = "up" if target_up else "down"
+        with IPRoute() as ipr:
+            indices = ipr.link_lookup(ifname=ifname)
+            if not indices:
+                raise RuntimeError(f"Interface {ifname} not found while propagating link state")
+            ipr.link("set", index=indices[0], state=state_name)
+
+
+class BridgeLinkStateManager:
+    """Track bridge link-state watchers keyed by bridge name."""
+
+    def __init__(self) -> None:
+        self._watchers: dict[str, BridgeLinkStateWatcher] = {}
+        self._lock = threading.Lock()
+
+    def enable(self, bridge_name: str, poll_interval_seconds: Optional[float] = None) -> dict[str, Any]:
+        """Start or replace the watcher for the given bridge."""
+        normalized_interval = poll_interval_seconds or settings.bridge_link_state_poll_interval_seconds
+        with self._lock:
+            old_watcher = self._watchers.pop(bridge_name, None)
+
+        if old_watcher is not None:
+            old_watcher.stop()
+
+        watcher = BridgeLinkStateWatcher(bridge_name, normalized_interval)
+        watcher.start()
+
+        with self._lock:
+            self._watchers[bridge_name] = watcher
+
+        return watcher.status()
+
+    def disable(self, bridge_name: str) -> dict[str, Any]:
+        """Stop the watcher for one bridge."""
+        with self._lock:
+            watcher = self._watchers.pop(bridge_name, None)
+
+        if watcher is None:
+            return {
+                "bridge": bridge_name,
+                "active": False,
+                "message": "watcher not enabled",
+            }
+
+        watcher.stop()
+        status = watcher.status()
+        status["active"] = False
+        return status
+
+    def get_status(self, bridge_name: str) -> Optional[dict[str, Any]]:
+        """Return the current watcher status for one bridge, if present."""
+        with self._lock:
+            watcher = self._watchers.get(bridge_name)
+        return watcher.status() if watcher is not None else None
+
+    def list_statuses(self) -> list[dict[str, Any]]:
+        """Return the current status for all bridge watchers."""
+        with self._lock:
+            watchers = list(self._watchers.values())
+        return [watcher.status() for watcher in sorted(watchers, key=lambda item: item.bridge_name)]
+
+    def stop(self) -> None:
+        """Stop all running watchers."""
+        with self._lock:
+            watchers = list(self._watchers.values())
+            self._watchers.clear()
+
+        for watcher in watchers:
+            watcher.stop()
+
+
+bridge_link_state_manager = BridgeLinkStateManager()

backend/src/utilities/interface_bridge_helpers.py

@@ -1,4 +1,4 @@
-from typing import List, Dict, Optional
+from typing import List, Optional
 import logging
 import os
 
@@ -30,6 +30,49 @@ def check_interface_up(iface: str) -> bool:
         return False
 
 
+def _read_sysfs_text(path: str) -> Optional[str]:
+    """Read one sysfs file and return stripped text, or `None` if unavailable."""
+    try:
+        with open(path, "r") as f:
+            return f.read().strip()
+    except FileNotFoundError:
+        return None
+    except Exception:
+        logger.exception("Error reading sysfs path %s", path)
+        return None
+
+
+def read_interface_operstate(iface: str) -> Optional[str]:
+    """Return the kernel operstate string for an interface."""
+    return _read_sysfs_text(f"/sys/class/net/{iface}/operstate")
+
+
+def read_interface_carrier(iface: str) -> Optional[bool]:
+    """Return the carrier state for an interface if available."""
+    value = _read_sysfs_text(f"/sys/class/net/{iface}/carrier")
+    if value is None:
+        return None
+
+    try:
+        return int(value, 10) == 1
+    except ValueError:
+        logger.warning("Unexpected carrier value for %s: %r", iface, value)
+        return None
+
+
+def read_interface_admin_up(iface: str) -> Optional[bool]:
+    """Return whether the interface has the IFF_UP flag set."""
+    value = _read_sysfs_text(f"/sys/class/net/{iface}/flags")
+    if value is None:
+        return None
+
+    try:
+        return bool(int(value, 0) & 0x1)
+    except ValueError:
+        logger.warning("Unexpected flags value for %s: %r", iface, value)
+        return None
+
+
 def _read_bridge_ports_from_sysfs(bridge: str) -> List[str]:
     """
     Read bridge member interfaces from sysfs. Internal helper that always reads.

frontend/src/api/apiClient.ts

@@ -3,6 +3,8 @@ import axios from 'axios';
 import { CreateRuleRequest, ExecResult, RulesetModel } from '../types/firewall';
 import {
   BridgeCreateRequest,
+  BridgeLinkStateEnableRequest,
+  BridgeLinkStateWatcherStatus,
   BridgeInfo,
   BridgeRemoveRequest,
   FullState,
@@ -90,6 +92,30 @@ export const removeBridge = async (req: BridgeRemoveRequest) => {
   return res.data;
 };
 
+export const fetchBridgeLinkStateWatchers = async (): Promise<BridgeLinkStateWatcherStatus[]> => {
+  const res = await api.get<BridgeLinkStateWatcherStatus[]>('/network/bridge/link-state-watchers');
+  return res.data;
+};
+
+export const enableBridgeLinkStateWatcher = async (
+  bridgeName: string,
+  req: BridgeLinkStateEnableRequest,
+): Promise<BridgeLinkStateWatcherStatus> => {
+  const res = await api.post<BridgeLinkStateWatcherStatus>(
+    `/network/bridge/${encodeURIComponent(bridgeName)}/link-state-watcher/enable`,
+    req,
+  );
+  return res.data;
+};
+
+export const disableBridgeLinkStateWatcher = async (bridgeName: string): Promise<BridgeLinkStateWatcherStatus> => {
+  const res = await api.post<BridgeLinkStateWatcherStatus>(
+    `/network/bridge/${encodeURIComponent(bridgeName)}/link-state-watcher/disable`,
+    {},
+  );
+  return res.data;
+};
+
 export const startSniffer = async (payload: SnifferStartRequest): Promise<SnifferStartResponse> => {
   const res = await api.post<SnifferStartResponse>('/sniffer/start', payload);
   return res.data;

frontend/src/pages/Network.tsx

@@ -3,8 +3,10 @@ import {
   Button,
   Card,
   Col,
+  Descriptions,
   Form,
   Input,
+  InputNumber,
   Modal,
   notification,
   Popconfirm,
@@ -18,20 +20,43 @@ import {
 import type { ColumnsType } from 'antd/es/table';
 import { useEffect, useMemo, useState } from 'react';
 
-import { createBridge, fetchFullState, removeBridge } from '../api/apiClient';
-import type { BridgeInfo, FullState, InterfaceInfo } from '../types/network';
+import {
+  createBridge,
+  disableBridgeLinkStateWatcher,
+  enableBridgeLinkStateWatcher,
+  fetchBridgeLinkStateWatchers,
+  fetchFullState,
+  removeBridge,
+} from '../api/apiClient';
+import type {
+  BridgeInfo,
+  BridgeLinkStateWatcherStatus,
+  FullState,
+  InterfaceInfo,
+} from '../types/network';
 
 const { Title, Paragraph } = Typography;
 
 export default function Network() {
   const [bridgeModalVisible, setBridgeModalVisible] = useState(false);
+  const [watcherModalVisible, setWatcherModalVisible] = useState(false);
   const [bridgeForm] = Form.useForm();
+  const [watcherForm] = Form.useForm();
   const [networkState, setNetworkState] = useState<FullState>();
+  const [watcherStatuses, setWatcherStatuses] = useState<Record<string, BridgeLinkStateWatcherStatus>>({});
+  const [watcherBridgeName, setWatcherBridgeName] = useState<string>();
+  const [watcherBusyBridge, setWatcherBusyBridge] = useState<string>();
 
-  const getFullState = (silent = false) => {
-    fetchFullState()
-      .then((state) => {
+  const getNetworkPageState = (silent = false) => {
+    Promise.all([fetchFullState(), fetchBridgeLinkStateWatchers()])
+      .then(([state, watchers]) => {
         setNetworkState(state);
+        setWatcherStatuses(
+          watchers.reduce<Record<string, BridgeLinkStateWatcherStatus>>((acc, watcher) => {
+            acc[watcher.bridge] = watcher;
+            return acc;
+          }, {}),
+        );
         if (!silent) {
           notification.success({
             message: 'Success',
@@ -49,9 +74,26 @@ export default function Network() {
   };
 
   useEffect(() => {
-    getFullState(true);
+    getNetworkPageState(true);
   }, []);
 
+  const hasActiveWatchers = useMemo(
+    () => Object.values(watcherStatuses).some((watcher) => watcher.active),
+    [watcherStatuses],
+  );
+
+  useEffect(() => {
+    if (!hasActiveWatchers) {
+      return undefined;
+    }
+
+    const intervalId = window.setInterval(() => {
+      getNetworkPageState(true);
+    }, 2000);
+
+    return () => window.clearInterval(intervalId);
+  }, [hasActiveWatchers]);
+
   const interfaceOptions = useMemo(
     () =>
       networkState?.interfaces.map((iface: InterfaceInfo) => ({
@@ -61,6 +103,53 @@ export default function Network() {
     [networkState],
   );
 
+  const watcherData = useMemo(
+    () =>
+      (networkState?.bridges ?? []).map((bridge) => ({
+        bridge,
+        watcher: watcherStatuses[bridge.ifname],
+      })),
+    [networkState, watcherStatuses],
+  );
+
+  const watcherMemberColumns = useMemo(
+    () => [
+      { title: 'Member', dataIndex: 'ifname', key: 'ifname' },
+      {
+        title: 'Admin',
+        dataIndex: 'admin_up',
+        key: 'admin_up',
+        width: 90,
+        render: (value: boolean | null | undefined) => <Tag color={value ? 'green' : 'default'}>{value ? 'up' : 'down'}</Tag>,
+      },
+      {
+        title: 'Carrier',
+        dataIndex: 'carrier_up',
+        key: 'carrier_up',
+        width: 100,
+        render: (value: boolean | null | undefined) => <Tag color={value ? 'green' : 'default'}>{value ? 'up' : 'down'}</Tag>,
+      },
+      {
+        title: 'Operstate',
+        dataIndex: 'operstate',
+        key: 'operstate',
+        render: (value: string | null | undefined) => <Tag>{value ?? 'unknown'}</Tag>,
+      },
+      {
+        title: 'Role',
+        key: 'role',
+        width: 120,
+        render: (_: unknown, record: { link_ready: boolean; suppressed: boolean }) => {
+          if (record.suppressed) {
+            return <Tag color="orange">suppressed</Tag>;
+          }
+          return <Tag color={record.link_ready ? 'green' : 'red'}>{record.link_ready ? 'ready' : 'failing'}</Tag>;
+        },
+      },
+    ],
+    [],
+  );
+
   const interfaceColumns: ColumnsType<InterfaceInfo> = useMemo(
     () => [
       { title: 'IfIndex', dataIndex: 'ifindex', key: 'ifindex', width: 90 },
@@ -100,23 +189,58 @@ export default function Network() {
         key: 'members',
         render: (members: any[]) => (members?.length ? members.map((member) => member.ifname).join(', ') : '—'),
       },
+      {
+        title: 'Link Watcher',
+        key: 'watcher',
+        width: 160,
+        render: (_, record: BridgeInfo) => {
+          const watcher = watcherStatuses[record.ifname];
+          if (!watcher?.active) {
+            return <Tag>disabled</Tag>;
+          }
+          if (watcher.last_error) {
+            return <Tag color="red">error</Tag>;
+          }
+          if (watcher.suppressed_members.length > 0) {
+            return <Tag color="orange">propagating</Tag>;
+          }
+          return <Tag color="green">active</Tag>;
+        },
+      },
       {
         title: 'Actions',
         key: 'actions',
-        width: 140,
+        width: 260,
         render: (_, record: BridgeInfo) => (
-          <Popconfirm
-            title={`Remove bridge ${record.ifname}?`}
-            onConfirm={() => handleRemoveBridge(record.ifname)}
-            okText="Remove"
-            cancelText="Cancel"
-          >
-            <Button danger icon={<DeleteOutlined />} />
-          </Popconfirm>
+          <Space>
+            {watcherStatuses[record.ifname]?.active ? (
+              <Button
+                onClick={() => handleDisableWatcher(record.ifname)}
+                loading={watcherBusyBridge === record.ifname}
+              >
+                Disable watcher
+              </Button>
+            ) : (
+              <Button
+                onClick={() => openEnableWatcherModal(record.ifname)}
+                loading={watcherBusyBridge === record.ifname}
+              >
+                Enable watcher
+              </Button>
+            )}
+            <Popconfirm
+              title={`Remove bridge ${record.ifname}?`}
+              onConfirm={() => handleRemoveBridge(record.ifname)}
+              okText="Remove"
+              cancelText="Cancel"
+            >
+              <Button danger icon={<DeleteOutlined />} />
+            </Popconfirm>
+          </Space>
         ),
       },
     ],
-    [],
+    [watcherBusyBridge, watcherStatuses],
   );
 
   function handleCreateBridge(values: { name: string; interfaces?: string[] }) {
@@ -128,7 +252,7 @@ export default function Network() {
           description: `Bridge ${values.name} created`,
         });
         setBridgeModalVisible(false);
-        getFullState(true);
+        getNetworkPageState(true);
         bridgeForm.resetFields();
       })
       .catch((error) => {
@@ -147,7 +271,7 @@ export default function Network() {
           message: 'Success',
           description: `Bridge ${name} removed`,
         });
-        getFullState(true);
+        getNetworkPageState(true);
       })
       .catch((error) => {
         console.error(error);
@@ -158,6 +282,63 @@ export default function Network() {
       });
   }
 
+  function openEnableWatcherModal(bridgeName: string) {
+    setWatcherBridgeName(bridgeName);
+    watcherForm.setFieldsValue({ poll_interval_seconds: 0.25 });
+    setWatcherModalVisible(true);
+  }
+
+  function handleEnableWatcher(values: { poll_interval_seconds: number }) {
+    if (!watcherBridgeName) {
+      return;
+    }
+
+    setWatcherBusyBridge(watcherBridgeName);
+    enableBridgeLinkStateWatcher(watcherBridgeName, values)
+      .then(() => {
+        notification.success({
+          message: 'Success',
+          description: `Link-state watcher enabled for ${watcherBridgeName}`,
+        });
+        setWatcherModalVisible(false);
+        setWatcherBridgeName(undefined);
+        watcherForm.resetFields();
+        getNetworkPageState(true);
+      })
+      .catch((error) => {
+        console.error(error);
+        notification.error({
+          message: 'Error',
+          description: (error as Error).message ?? 'Failed to enable link-state watcher',
+        });
+      })
+      .finally(() => {
+        setWatcherBusyBridge(undefined);
+      });
+  }
+
+  function handleDisableWatcher(bridgeName: string) {
+    setWatcherBusyBridge(bridgeName);
+    disableBridgeLinkStateWatcher(bridgeName)
+      .then(() => {
+        notification.success({
+          message: 'Success',
+          description: `Link-state watcher disabled for ${bridgeName}`,
+        });
+        getNetworkPageState(true);
+      })
+      .catch((error) => {
+        console.error(error);
+        notification.error({
+          message: 'Error',
+          description: (error as Error).message ?? 'Failed to disable link-state watcher',
+        });
+      })
+      .finally(() => {
+        setWatcherBusyBridge(undefined);
+      });
+  }
+
   return (
     <div style={{ padding: 16 }}>
       <Row justify="space-between" align="middle" style={{ marginBottom: 12 }}>
@@ -166,7 +347,7 @@ export default function Network() {
           <Paragraph type="secondary">View system interfaces and manage network bridges.</Paragraph>
         </Col>
         <Col>
-          <Button icon={<ReloadOutlined />} onClick={() => getFullState()}>
+          <Button icon={<ReloadOutlined />} onClick={() => getNetworkPageState()}>
             Refresh
           </Button>
         </Col>
@@ -194,7 +375,7 @@ export default function Network() {
                 icon={<PlusOutlined />}
                 type="primary"
                 onClick={() => {
-                  getFullState(true);
+                  getNetworkPageState(true);
                   setBridgeModalVisible(true);
                 }}
               />
@@ -211,6 +392,78 @@ export default function Network() {
         </Col>
       </Row>
 
+      <Row style={{ marginTop: 16 }}>
+        <Col span={24}>
+          <Card title="Bridge Link-State Propagation">
+            <Space direction="vertical" style={{ width: '100%' }} size="middle">
+              <Paragraph type="secondary" style={{ marginBottom: 0 }}>
+                Enable a watcher on a bridge to force the sibling bridge ports down when one member loses link.
+              </Paragraph>
+              {(networkState?.bridges.length ?? 0) === 0 ? (
+                <Paragraph type="secondary" style={{ marginBottom: 0 }}>
+                  No bridges available.
+                </Paragraph>
+              ) : (
+                watcherData.map(({ bridge, watcher }) => {
+                  const members = Object.values(watcher?.members ?? {});
+
+                  return (
+                    <Card
+                      key={bridge.ifname}
+                      size="small"
+                      title={
+                        <Space>
+                          <span>{bridge.ifname}</span>
+                          <Tag color={watcher?.active ? 'green' : 'default'}>
+                            {watcher?.active ? 'watching' : 'disabled'}
+                          </Tag>
+                          {watcher?.last_error ? <Tag color="red">error</Tag> : null}
+                        </Space>
+                      }
+                      extra={
+                        watcher?.active ? (
+                          <Button onClick={() => handleDisableWatcher(bridge.ifname)} loading={watcherBusyBridge === bridge.ifname}>
+                            Disable
+                          </Button>
+                        ) : (
+                          <Button onClick={() => openEnableWatcherModal(bridge.ifname)} loading={watcherBusyBridge === bridge.ifname}>
+                            Enable
+                          </Button>
+                        )
+                      }
+                    >
+                      <Descriptions size="small" column={4} style={{ marginBottom: members.length ? 12 : 0 }}>
+                        <Descriptions.Item label="Members">{bridge.members.map((member) => member.ifname).join(', ') || '—'}</Descriptions.Item>
+                        <Descriptions.Item label="Poll interval">
+                          {watcher?.poll_interval_seconds ? `${watcher.poll_interval_seconds}s` : '—'}
+                        </Descriptions.Item>
+                        <Descriptions.Item label="Suppressed">
+                          {watcher?.suppressed_members.length ? watcher.suppressed_members.join(', ') : 'none'}
+                        </Descriptions.Item>
+                        <Descriptions.Item label="Last action">{watcher?.last_action ?? watcher?.message ?? '—'}</Descriptions.Item>
+                      </Descriptions>
+                      {members.length ? (
+                        <Table
+                          rowKey={(row) => row.ifname}
+                          dataSource={members}
+                          columns={watcherMemberColumns}
+                          pagination={false}
+                          size="small"
+                        />
+                      ) : (
+                        <Paragraph type="secondary" style={{ marginBottom: 0 }}>
+                          {watcher?.active ? 'Waiting for watcher state.' : 'Watcher is disabled.'}
+                        </Paragraph>
+                      )}
+                    </Card>
+                  );
+                })
+              )}
+            </Space>
+          </Card>
+        </Col>
+      </Row>
+
       <Modal
         title="Create Bridge"
         open={bridgeModalVisible}
@@ -237,6 +490,30 @@ export default function Network() {
           </Form.Item>
         </Form>
       </Modal>
+
+      <Modal
+        title={watcherBridgeName ? `Enable Link-State Watcher for ${watcherBridgeName}` : 'Enable Link-State Watcher'}
+        open={watcherModalVisible}
+        onCancel={() => {
+          setWatcherModalVisible(false);
+          setWatcherBridgeName(undefined);
+          watcherForm.resetFields();
+        }}
+        onOk={() => watcherForm.submit()}
+      >
+        <Form form={watcherForm} layout="vertical" onFinish={handleEnableWatcher} initialValues={{ poll_interval_seconds: 0.25 }}>
+          <Form.Item
+            name="poll_interval_seconds"
+            label="Poll interval (seconds)"
+            rules={[{ required: true, message: 'Please provide a poll interval' }]}
+          >
+            <InputNumber min={0.05} max={10} step={0.05} precision={2} style={{ width: '100%' }} />
+          </Form.Item>
+          <Paragraph type="secondary" style={{ marginBottom: 0 }}>
+            When enabled, the backend suppresses sibling bridge ports if one member loses link and restores them after recovery.
+          </Paragraph>
+        </Form>
+      </Modal>
     </div>
   );
 }

frontend/src/types/network.ts

@@ -46,10 +46,36 @@ export interface BridgeCreateRequest {
   name: string;
   interfaces: string[];
 }
+
 export interface BridgeRemoveRequest {
   name: string;
 }
 
+export interface BridgeLinkStateEnableRequest {
+  poll_interval_seconds: number;
+}
+
+export interface BridgeMemberLinkStateInfo {
+  ifname: string;
+  admin_up?: boolean | null;
+  carrier_up?: boolean | null;
+  operstate?: string | null;
+  link_ready: boolean;
+  suppressed: boolean;
+}
+
+export interface BridgeLinkStateWatcherStatus {
+  bridge: string;
+  active: boolean;
+  poll_interval_seconds?: number | null;
+  last_poll_ts?: number | null;
+  last_error?: string | null;
+  last_action?: string | null;
+  suppressed_members: string[];
+  members: Record<string, BridgeMemberLinkStateInfo>;
+  message?: string | null;
+}
+
 // full-state response shape
 export interface FullState {
   interfaces: InterfaceInfo[];