Merge pull request #2816 from yueguobin/feature/traffic-insight-markers

feat: add traffic-insight markers (ubridge mark filter integration)

gns3server/api/routes/compute/cloud_nodes.py

@@ -184,6 +184,8 @@ async def update_cloud_nio(
     nio.filters.clear()
     if nio_data.filters:
         nio.filters = nio_data.filters
+    # NIO type is a Union (Ethernet/TAP/UDP); only UDPNIO carries markers.
+    nio.markers = getattr(nio_data, "markers", None) or {}
     await node.update_nio(port_number, nio)
     return nio.asdict()
 

gns3server/api/routes/compute/docker_nodes.py

@@ -29,7 +29,6 @@ from typing import Union
 from gns3server import schemas
 from gns3server.compute.docker import Docker
 from gns3server.compute.docker.docker_vm import DockerVM
-
 from .dependencies.authentication import compute_authentication, ws_compute_authentication
 
 responses = {404: {"model": schemas.ErrorMessage, "description": "Could not find project or Docker node"}}
@@ -293,6 +292,7 @@ async def update_docker_node_nio(
     nio.filters.clear()
     if nio_data.filters:
         nio.filters = nio_data.filters
+    nio.markers = nio_data.markers or {}
     await node.adapter_update_nio_binding(adapter_number, nio)
     return nio.asdict()
 

gns3server/api/routes/compute/dynamips_nodes.py

@@ -235,6 +235,7 @@ async def update_nio(
     nio.filters.clear()
     if nio_data.filters:
         nio.filters = nio_data.filters
+    nio.markers = nio_data.markers or {}
     await node.slot_update_nio_binding(adapter_number, port_number, nio)
     return nio.asdict()
 

gns3server/api/routes/compute/iou_nodes.py

@@ -254,6 +254,8 @@ async def update_iou_node_nio(
     nio.filters.clear()
     if nio_data.filters:
         nio.filters = nio_data.filters
+    # NIO type is a Union (Ethernet/TAP/UDP); only UDPNIO carries markers.
+    nio.markers = getattr(nio_data, "markers", None) or {}
     await node.adapter_update_nio_binding(adapter_number, port_number, nio)
     return nio.asdict()
 

gns3server/api/routes/compute/qemu_nodes.py

@@ -30,7 +30,6 @@ from gns3server import schemas
 from gns3server.compute import qemu
 from gns3server.compute.qemu import Qemu
 from gns3server.compute.qemu.qemu_vm import QemuVM
-
 from .dependencies.authentication import compute_authentication, ws_compute_authentication
 
 import logging
@@ -321,6 +320,7 @@ async def update_qemu_node_nio(
     if nio_data.filters:
         nio.filters = nio_data.filters
     nio.suspend = nio_data.suspend
+    nio.markers = nio_data.markers or {}
     await node.adapter_update_nio_binding(adapter_number, nio)
     return nio.asdict()
 

gns3server/api/routes/compute/vpcs_nodes.py

@@ -29,7 +29,6 @@ from uuid import UUID
 from gns3server import schemas
 from gns3server.compute.vpcs import VPCS
 from gns3server.compute.vpcs.vpcs_vm import VPCSVM
-
 from .dependencies.authentication import compute_authentication, ws_compute_authentication
 
 responses = {404: {"model": schemas.ErrorMessage, "description": "Could not find project or VMware node"}}
@@ -240,6 +239,7 @@ async def update_vpcs_node_nio(
     nio.filters.clear()
     if nio_data.filters:
         nio.filters = nio_data.filters
+    nio.markers = nio_data.markers or {}
     await node.port_update_nio_binding(port_number, nio)
     return nio.asdict()
 
@@ -303,6 +303,7 @@ async def stop_vpcs_node_capture(
     await node.stop_capture(port_number)
 
 
+
 @router.get(
     "/{node_id}/adapters/{adapter_number}/ports/{port_number}/capture/stream",
     dependencies=[Depends(compute_authentication)]

gns3server/api/routes/controller/links.py

@@ -27,7 +27,7 @@ from fastapi import APIRouter, Depends, Request, status, WebSocket
 from fastapi.responses import FileResponse, StreamingResponse
 from fastapi.encoders import jsonable_encoder
 from typing import List, Union
-from uuid import UUID
+from uuid import UUID, uuid4
 
 from gns3server.controller import Controller
 from gns3server.controller.controller_error import ControllerError
@@ -424,6 +424,97 @@ async def web_wireshark_websocket(
             pass
 
 
+@router.get(
+    "/{link_id}/markers",
+    dependencies=[Depends(has_privilege("Link.Audit"))]
+)
+async def get_markers(link: Link = Depends(dep_link)) -> dict:
+    """
+    Return all traffic-insight markers configured on this link.
+
+    Required privilege: Link.Audit
+    """
+
+    return link.markers
+
+
+@router.post(
+    "/{link_id}/markers",
+    status_code=status.HTTP_201_CREATED,
+    dependencies=[Depends(has_privilege("Link.Modify"))]
+)
+async def create_marker(
+    marker_data: schemas.MarkerCreate,
+    link: Link = Depends(dep_link)
+) -> dict:
+    """
+    Attach a traffic-insight marker to the link.
+    On BPF match uBridge emits MARK signals and appends packets to a pcap.
+
+    Required privilege: Link.Modify
+    """
+
+    # Auto-generate a link-unique name when the caller omits one. The short
+    # uuid suffix avoids the collision that `marker-{link.id[:8]}` alone would
+    # cause on the second anonymous marker on the same link (start_marker
+    # rejects duplicate names).
+    if marker_data.name and marker_data.name.lower().startswith("global"):
+        raise ControllerError('Names starting with "global" are reserved for inherited markers')
+    name = marker_data.name or f"marker-{link.id[:8]}-{uuid4().hex[:4]}"
+    await link.start_marker(
+        name=name,
+        bpf=marker_data.bpf,
+        tag=marker_data.tag,
+        color=marker_data.color,
+        highlight_duration=marker_data.highlight_duration,
+    )
+    return link.markers.get(name, {})
+
+
+@router.delete(
+    "/{link_id}/markers/{marker_name}",
+    status_code=status.HTTP_204_NO_CONTENT,
+    dependencies=[Depends(has_privilege("Link.Modify"))]
+)
+async def delete_marker(
+    marker_name: str,
+    link: Link = Depends(dep_link)
+) -> None:
+    """
+    Remove a traffic-insight marker from the link.
+
+    Required privilege: Link.Modify
+    """
+
+    await link.stop_marker(marker_name)
+
+
+@router.put(
+    "/{link_id}/markers/{marker_name}",
+    dependencies=[Depends(has_privilege("Link.Modify"))]
+)
+async def update_marker(
+    marker_name: str,
+    marker_data: schemas.MarkerCreate,
+    link: Link = Depends(dep_link)
+) -> dict:
+    """
+    Update a traffic-insight marker (change BPF, tag, or enabled).
+
+    Required privilege: Link.Modify
+    """
+
+    await link.update_marker(
+        name=marker_name,
+        bpf=marker_data.bpf if marker_data.bpf else None,
+        tag=marker_data.tag,
+        color=marker_data.color,
+        enabled=marker_data.enabled,
+        highlight_duration=marker_data.highlight_duration,
+    )
+    return link.markers.get(marker_name, {})
+
+
 @router.get(
     "/{link_id}/iface",
     response_model=Union[schemas.UDPPortInfo, schemas.EthernetPortInfo],

gns3server/api/routes/controller/projects.py

@@ -203,6 +203,119 @@ def get_project_stats(project: Project = Depends(dep_project)) -> dict:
     return project.stats()
 
 
+@router.get("/{project_id}/markers", dependencies=[Depends(has_privilege("Project.Audit"))])
+def get_project_markers(project: Project = Depends(dep_project)) -> dict:
+    """
+    Return all traffic-insight markers across every link in the project.
+
+    Each entry is keyed ``"{link_id}/{marker_name}"`` and carries the
+    marker's BPF, tag, color, enabled flag, plus its parent ``link_id``
+    and capture-side ``node_id`` for frontend filtering / grouping.
+
+    Required privilege: Project.Audit
+    """
+
+    return project.markers
+
+
+# ---------------------------------------------------------------------------
+# Project-level marker definitions (global rules inherited by every link)
+# ---------------------------------------------------------------------------
+
+@router.get(
+    "/{project_id}/marker-definitions",
+    dependencies=[Depends(has_privilege("Project.Audit"))]
+)
+def get_marker_definitions(project: Project = Depends(dep_project)) -> dict:
+    """
+    Return all project-level marker definitions with their bound link IDs.
+
+    Required privilege: Project.Audit
+    """
+
+    result = {}
+    for name, d in project.marker_definitions.items():
+        # Collect which links currently carry an inherited copy.
+        bound = [
+            lid for lid, link in project.links.items()
+            if f"global-{name}" in link.markers
+            and link.markers[f"global-{name}"].get("inherited_from") == name
+        ]
+        result[name] = {**d, "link_ids": bound}
+    return result
+
+
+@router.post(
+    "/{project_id}/marker-definitions",
+    status_code=status.HTTP_201_CREATED,
+    dependencies=[Depends(has_privilege("Project.Modify"))]
+)
+async def create_marker_definition(
+    def_data: schemas.MarkerDefinitionCreate,
+    project: Project = Depends(dep_project)
+) -> dict:
+    """
+    Create a project-level marker definition and fan out to every link.
+
+    Required privilege: Project.Modify
+    """
+
+    if def_data.name and def_data.name.lower().startswith("global"):
+        raise ControllerError('Names starting with "global" are reserved for inherited markers')
+    name = def_data.name or f"def-{project.id[:8]}"
+    await project.create_marker_definition(
+        name=name,
+        bpf=def_data.bpf,
+        tag=def_data.tag,
+        color=def_data.color,
+        highlight_duration=def_data.highlight_duration,
+    )
+    return project.marker_definitions.get(name, {})
+
+
+@router.put(
+    "/{project_id}/marker-definitions/{def_name}",
+    dependencies=[Depends(has_privilege("Project.Modify"))]
+)
+async def update_marker_definition(
+    def_name: str,
+    def_data: schemas.MarkerDefinitionCreate,
+    project: Project = Depends(dep_project)
+) -> dict:
+    """
+    Update a marker definition and sync all inherited copies on every link.
+
+    Required privilege: Project.Modify
+    """
+
+    await project.update_marker_definition(
+        name=def_name,
+        bpf=def_data.bpf if def_data.bpf else None,
+        tag=def_data.tag,
+        color=def_data.color,
+        highlight_duration=def_data.highlight_duration,
+    )
+    return project.marker_definitions.get(def_name, {})
+
+
+@router.delete(
+    "/{project_id}/marker-definitions/{def_name}",
+    status_code=status.HTTP_204_NO_CONTENT,
+    dependencies=[Depends(has_privilege("Project.Modify"))]
+)
+async def delete_marker_definition(
+    def_name: str,
+    project: Project = Depends(dep_project)
+) -> None:
+    """
+    Delete a marker definition and remove all inherited copies from every link.
+
+    Required privilege: Project.Modify
+    """
+
+    await project.delete_marker_definition(def_name)
+
+
 @router.post(
     "/{project_id}/close",
     status_code=status.HTTP_204_NO_CONTENT,

gns3server/compute/base_manager.py

@@ -356,6 +356,7 @@ class BaseManager:
                 raise ComputeError(f"Could not create an UDP connection to {rhost}:{rport}: {e}")
             nio = NIOUDP(lport, rhost, rport)
             nio.filters = nio_settings.get("filters", {})
+            nio.markers = nio_settings.get("markers", {})
             nio.suspend = nio_settings.get("suspend", False)
         elif nio_settings["type"] == "nio_tap":
             tap_device = nio_settings["tap_device"]

gns3server/compute/base_node.py

@@ -935,9 +935,46 @@ class BaseNode:
                 f"Hypervisor {self._ubridge_hypervisor.host}:{self._ubridge_hypervisor.port} has successfully started"
             )
             await self._ubridge_hypervisor.connect()
+            # Tell this uBridge where to send MARK signals and which node id to
+            # tag them with. Marker is opt-in and inert until a `mark` filter is
+            # added, so this never disturbs the data plane.
+            await self._ubridge_configure_marker_sink()
         # save if privileged are required in case uBridge needs to be restarted in self._ubridge_send()
         self._ubridge_require_privileged_access = require_privileged_access
 
+    async def _ubridge_configure_marker_sink(self):
+        """
+        Point this node's uBridge at the compute's marker UDP sink and tag its
+        signals with this node's id. Safe to call before any marker filter
+        exists — uBridge stays inert until a ``mark`` filter is configured.
+
+        Old uBridge builds without the marker module are tolerated: the failure
+        is downgraded to a warning so node start is not blocked by an opt-in
+        observability feature.
+        """
+
+        from gns3server.compute.marker.marker_manager import MarkerManager
+
+        manager = MarkerManager.instance()
+        if not manager.running or not manager.host or not manager.port:
+            return
+        if self._ubridge_hypervisor is None:
+            return
+        try:
+            # Talk to the hypervisor directly, NOT via _ubridge_send: this runs
+            # inside _start_ubridge, which is reached THROUGH _ubridge_send when
+            # uBridge starts lazily (e.g. linking a stopped node). _ubridge_send's
+            # lock is non-reentrant, so calling it again here would deadlock on
+            # the held ___ubridge_send_lock. uBridge is already running and
+            # connected at this point, so the raw hypervisor send is safe.
+            await self._ubridge_hypervisor.send(f"marker sink {manager.host} {manager.port}")
+            await self._ubridge_hypervisor.send(f"marker node {self._id}")
+        except UbridgeError:
+            log.warning(
+                "uBridge does not support the marker module; traffic insight disabled for node %r",
+                self.name,
+            )
+
     async def _stop_ubridge(self):
         """
         Stops uBridge.
@@ -983,10 +1020,12 @@ class BaseNode:
 
         await self._ubridge_send(f"bridge start {bridge_name}")
         await self._ubridge_apply_filters(bridge_name, destination_nio.filters)
+        await self._ubridge_apply_markers(bridge_name, destination_nio)
 
     async def update_ubridge_udp_connection(self, bridge_name, source_nio, destination_nio):
         if destination_nio:
             await self._ubridge_apply_filters(bridge_name, destination_nio.filters)
+            await self._ubridge_apply_markers(bridge_name, destination_nio)
 
     async def ubridge_delete_bridge(self, name):
         """
@@ -1042,6 +1081,86 @@ class BaseNode:
                 )
                 i += 1
 
+    async def _ubridge_add_marker_filter(self, bridge_name, name, bpf, pcap_path, tag=None, link_id=None):
+        """
+        Attach a `mark` packet filter to a uBridge bridge for traffic insight.
+
+        On BPF match uBridge (a) emits a UDP MARK signal to the configured sink
+        and (b) appends the packet to ``pcap_path``. Unlike the impairment
+        filters, this is an observability tap: it never drops or alters traffic,
+        and it is added/removed on its own (not via reset_packet_filters) so the
+        pcap is not closed/reopened on unrelated filter changes.
+
+        :param bridge_name: uBridge bridge carrying the link's traffic
+        :param name: stable, gns3server-chosen filter name (pcap identity + echoed in signals)
+        :param bpf: libpcap BPF expression
+        :param pcap_path: absolute path ubridge appends matched packets to
+        :param tag: optional correlation id echoed in MARK signals
+        """
+
+        # mark <bpf> [tag <id>] [pcap <path>] — tag/pcap keyword pairs, any order.
+        # name travels from the controller REST layer (MarkerCreate schema) but is
+        # validated here too as defense-in-depth against hand-edited topology files.
+        # Note: "global-*" names are legitimate here — they come from project-level
+        # marker definitions (inherit_marker). The prefix is only forbidden at the
+        # user-facing schema layer, not at the uBridge boundary.
+        _MARKER_NAME_RE = re.compile(r"^[A-Za-z0-9][A-Za-z0-9_.-]*$")
+        if not _MARKER_NAME_RE.match(name):
+            raise UbridgeError(f"Invalid marker name: {name!r}")
+        cmd = 'bridge add_packet_filter {bridge} {name} mark "{bpf}"'.format(
+            bridge=bridge_name, name=name, bpf=bpf
+        )
+        if tag is not None:
+            cmd += f" tag {tag}"
+        # Per-link attribution (contract §3.2): when one ubridge bridge serves
+        # several GNS3 links (e.g. IOU's per-node bridge), bridge+filter collide,
+        # so the link id is the only way to tell signals — and pcap files — apart.
+        if link_id:
+            cmd += f" link {link_id}"
+        cmd += ' pcap "{path}"'.format(path=pcap_path)
+        # Let BPF compile errors propagate — the marker is the user's intent, so a
+        # bad expression must surface instead of being silently dropped.
+        await self._ubridge_send(cmd)
+
+    async def _ubridge_apply_markers(self, bridge_name, nio):
+        """
+        (Re-)apply every traffic-insight marker carried by *nio* to the uBridge
+        bridge *bridge_name*.  Called from ``add_ubridge_udp_connection`` (bridge
+        creation / node restart) and ``update_ubridge_udp_connection`` (NIO update
+        — the preceding ``_ubridge_apply_filters`` has already issued
+        ``reset_packet_filters``, so we must re-add markers to survive the reset).
+        """
+        from gns3server.compute.marker.marker_manager import MarkerManager
+
+        markers = nio.markers if hasattr(nio, 'markers') else {}
+        if not markers:
+            return
+
+        manager = MarkerManager.instance()
+        markers_dir = self.project.markers_working_directory()
+        for name, spec in markers.items():
+            bpf = spec.get("bpf", "")
+            tag = spec.get("tag")
+            link_id = spec.get("link_id", "")
+            pcap_path = os.path.join(
+                markers_dir, f"{self._id}_{link_id}_{name}.pcap"
+            )
+            try:
+                await self._ubridge_add_marker_filter(bridge_name, name, bpf, pcap_path, tag, link_id)
+            except UbridgeError as e:
+                # Swallow BPF compile errors (warn + skip) so a single bad
+                # expression can't break link creation / node restart — mirrors
+                # _ubridge_apply_filters, which does the same for packet filters.
+                if "syntax error" in str(e).lower() or "compile filter" in str(e).lower():
+                    message = f"Warning: ignoring marker '{name}' due to BPF syntax error: {e}"
+                    log.warning(message)
+                    self.project.emit("log.warning", {"message": message})
+                    continue
+                raise
+            manager.register(
+                str(self.project.id), self._id, name, link_id, tag
+            )
+
     async def _add_ubridge_ethernet_connection(self, bridge_name, ethernet_interface, block_host_traffic=False):
         """
         Creates a connection with an Ethernet interface in uBridge.

gns3server/compute/builtin/nodes/cloud.py

@@ -312,6 +312,7 @@ class Cloud(BaseNode):
         )
 
         await self._ubridge_apply_filters(bridge_name, nio.filters)
+        await self._ubridge_apply_markers(bridge_name, nio)
         if port_info["type"] in ("ethernet", "tap"):
 
             if not self.manager.has_privileged_access(self.ubridge_path):
@@ -452,6 +453,7 @@ class Cloud(BaseNode):
         bridge_name = f"{self._id}-{port_number}"
         if self._ubridge_hypervisor and self._ubridge_hypervisor.is_running():
             await self._ubridge_apply_filters(bridge_name, nio.filters)
+            await self._ubridge_apply_markers(bridge_name, nio)
 
     async def _delete_ubridge_connection(self, port_number):
         """

gns3server/compute/docker/docker_vm.py

@@ -1228,6 +1228,7 @@ class DockerVM(BaseNode):
             )
         await self._ubridge_send(f"bridge start {bridge_name}")
         await self._ubridge_apply_filters(bridge_name, nio.filters)
+        await self._ubridge_apply_markers(bridge_name, nio)
 
     async def adapter_add_nio_binding(self, adapter_number, nio):
         """
@@ -1268,7 +1269,7 @@ class DockerVM(BaseNode):
             bridge_name = f"bridge{adapter_number}"
             if bridge_name in self._bridges:
                 await self._ubridge_apply_filters(bridge_name, nio.filters)
-
+                await self._ubridge_apply_markers(bridge_name, nio)
     async def adapter_remove_nio_binding(self, adapter_number):
         """
         Removes an adapter NIO binding.

gns3server/compute/dynamips/__init__.py

@@ -376,6 +376,7 @@ class Dynamips(BaseManager):
                 raise DynamipsError(f"Could not create an UDP connection to {rhost}:{rport}: {e}")
             nio = NIOUDP(node, lport, rhost, rport)
             nio.filters = nio_settings.get("filters", {})
+            nio.markers = nio_settings.get("markers", {})
             nio.suspend = nio_settings.get("suspend", False)
         elif nio_settings["type"] == "nio_generic_ethernet":
             ethernet_device = nio_settings["ethernet_device"]

gns3server/compute/dynamips/nios/nio.py

@@ -40,6 +40,7 @@ class NIO:
         self._hypervisor = hypervisor
         self._name = name
         self._filters = {}
+        self._markers = {}
         self._suspended = False
         self._capturing = False
         self._pcap_output_file = ""
@@ -303,6 +304,26 @@ class NIO:
         assert isinstance(new_filters, dict)
         self._filters = new_filters
 
+    @property
+    def markers(self):
+        """
+        Returns the list of traffic-insight markers for this NIO.
+
+        :returns: markers (dictionary)
+        """
+
+        return self._markers
+
+    @markers.setter
+    def markers(self, new_markers):
+        """
+        Set markers for this NIO.
+
+        :param new_markers: markers (dictionary)
+        """
+
+        self._markers = new_markers
+
     @property
     def capturing(self):
         """

gns3server/compute/dynamips/nios/nio_udp.py

@@ -82,10 +82,12 @@ class NIOUDP(NIO):
         self._source_nio = nio_udp.NIOUDP(self._local_tunnel_rport, "127.0.0.1", self._local_tunnel_lport)
         self._destination_nio = nio_udp.NIOUDP(self._lport, self._rhost, self._rport)
         self._destination_nio.filters = self._filters
+        self._destination_nio.markers = self._markers
         await self._node.add_ubridge_udp_connection(self._bridge_name, self._source_nio, self._destination_nio)
 
     async def update(self):
         self._destination_nio.filters = self._filters
+        self._destination_nio.markers = self._markers
         await self._node.update_ubridge_udp_connection(self._bridge_name, self._source_nio, self._destination_nio)
 
     async def close(self):

gns3server/compute/iou/iou_vm.py

@@ -746,6 +746,7 @@ class IOUVM(BaseNode):
                         )
 
                     await self._ubridge_apply_filters(bay_id, unit_id, nio.filters)
+                    await self._ubridge_apply_markers(bay_id, unit_id, nio)
                 unit_id += 1
             bay_id += 1
 
@@ -1067,6 +1068,7 @@ class IOUVM(BaseNode):
                 )
             )
             await self._ubridge_apply_filters(adapter_number, port_number, nio.filters)
+            await self._ubridge_apply_markers(adapter_number, port_number, nio)
 
     async def adapter_update_nio_binding(self, adapter_number, port_number, nio):
         """
@@ -1079,6 +1081,7 @@ class IOUVM(BaseNode):
 
         if self.ubridge:
             await self._ubridge_apply_filters(adapter_number, port_number, nio.filters)
+            await self._ubridge_apply_markers(adapter_number, port_number, nio)
 
     async def _ubridge_apply_filters(self, adapter_number, port_number, filters):
         """
@@ -1095,6 +1098,64 @@ class IOUVM(BaseNode):
             cmd = "iol_bridge add_packet_filter {} {}".format(location, filter)
             await self._ubridge_send(cmd)
 
+    async def _ubridge_apply_markers(self, adapter_number, port_number, nio):
+        """
+        (Re-)apply traffic-insight markers to the IOL bridge.
+
+        IOU uses ``iol_bridge`` (not ``bridge``) and the ``add_packet_filter``
+        command carries extra ``{bay} {unit}`` positional arguments between the
+        bridge name and the filter name — this override mirrors the pattern in
+        ``_ubridge_apply_filters`` above.
+
+        :param adapter_number: bay id
+        :param port_number: unit id
+        :param nio: NIO instance carrying ``nio.markers``
+        """
+        from gns3server.compute.marker.marker_manager import MarkerManager
+
+        markers = nio.markers if hasattr(nio, 'markers') else {}
+        if not markers:
+            return
+
+        manager = MarkerManager.instance()
+        markers_dir = self.project.markers_working_directory()
+        bridge_name = f"IOL-BRIDGE-{self.application_id + 512}"
+        location = "{bridge_name} {bay} {unit}".format(
+            bridge_name=bridge_name, bay=adapter_number, unit=port_number
+        )
+        for name, spec in markers.items():
+            bpf = spec.get("bpf", "")
+            tag = spec.get("tag")
+            link_id = spec.get("link_id", "")
+            pcap_path = os.path.join(
+                markers_dir, f"{self._id}_{link_id}_{name}.pcap"
+            )
+            # Build the iol_bridge marker filter command:
+            #   iol_bridge add_packet_filter {br} {bay} {unit} {name} mark "{bpf}" [tag {id}] pcap "{path}"
+            cmd = 'iol_bridge add_packet_filter {loc} {name} mark "{bpf}"'.format(
+                loc=location, name=name, bpf=bpf
+            )
+            if tag is not None:
+                cmd += f" tag {tag}"
+            # IOU uses one per-node IOL-BRIDGE for every link, so bridge+filter
+            # are identical across this node's links — `link` is the only way the
+            # controller can tell their signals apart (contract §3.2).
+            if link_id:
+                cmd += f" link {link_id}"
+            cmd += ' pcap "{path}"'.format(path=pcap_path)
+            try:
+                await self._ubridge_send(cmd)
+            except UbridgeError as e:
+                if "syntax error" in str(e).lower() or "compile filter" in str(e).lower():
+                    message = f"Warning: ignoring marker '{name}' due to BPF syntax error: {e}"
+                    log.warning(message)
+                    self.project.emit("log.warning", {"message": message})
+                    continue
+                raise
+            manager.register(
+                str(self.project.id), self._id, name, link_id, tag
+            )
+
     async def adapter_remove_nio_binding(self, adapter_number, port_number):
         """
         Removes an adapter NIO binding.

gns3server/compute/marker/__init__.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2024 GNS3 Technologies Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+#
+# Traffic-insight marker subsystem (compute side).
+#
+# ubridge's ``marker`` module is a passive tap: on a BPF match it emits a UDP
+# ``MARK`` signal to a configured sink and/or appends the packet to a pcap.
+# This package owns the compute-side UDP sink: one listener per compute process
+# serves every ubridge on that host, disambiguated by ``node=<id>``.

gns3server/compute/marker/marker_listener.py

@@ -0,0 +1,109 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2024 GNS3 Technologies Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import asyncio
+import logging
+
+log = logging.getLogger(__name__)
+
+
+class MarkerListener(asyncio.DatagramProtocol):
+    """
+    Receives ubridge ``MARK`` signal datagrams and turns each into a
+    ``marker.match`` notification.
+
+    Signal format (one datagram per match, ASCII)::
+
+        MARK <sec.usec> node=<id> filter=<name> tag=<tag> len=<n>\\n
+
+    The signal carries metadata only (no packet bytes). The compute-side
+    :class:`~gns3server.compute.marker.marker_manager.MarkerManager` registry
+    resolves ``(node_id, filter_name)`` to ``(project_id, link_id, tag)`` so the
+    event can be emitted on the right project-scoped notification stream.
+    """
+
+    def __init__(self, manager):
+        # MarkerManager owns this listener and the registry.
+        self._manager = manager
+        self.transport = None
+
+    def connection_made(self, transport):
+        self.transport = transport
+
+    def datagram_received(self, data, addr):
+        try:
+            self._handle(data)
+        except Exception:
+            # Never let a malformed datagram kill the listener.
+            log.exception("Failed to process MARK datagram from %s: %r", addr, data)
+
+    def _handle(self, data):
+        line = data.decode("utf-8", errors="replace").strip()
+        if not line.startswith("MARK"):
+            return
+
+        parts = line.split()
+        # parts[0] == "MARK"; parts[1] == "<sec.usec>"
+        if len(parts) < 2:
+            return
+
+        try:
+            ts = float(parts[1])
+        except ValueError:
+            log.warning("Ignoring MARK signal with bad timestamp: %r", line)
+            return
+
+        kv = {}
+        for token in parts[2:]:
+            if "=" in token:
+                key, value = token.split("=", 1)
+                kv[key] = value
+
+        node_id = kv.get("node")
+        filter_name = kv.get("filter")
+        if not node_id or not filter_name:
+            return
+
+        # "-" means the field was unset on the ubridge side (see contract §3.3).
+        link = kv.get("link")
+        tag = kv.get("tag")
+        length = kv.get("len")
+
+        project_id, link_id, registered_tag = self._manager.lookup(node_id, filter_name)
+        if project_id is None:
+            log.warning(
+                "MARK signal for unregistered node=%s filter=%s, dropping", node_id, filter_name
+            )
+            return
+
+        # `link=` is the authoritative per-link id (opaque, set by gns3server at
+        # filter install time). It disambiguates signals that share a node+filter
+        # across several links; fall back to the registry's link only for legacy
+        # signals that carry no `link=`.
+        signal_link = link if link and link != "-" else None
+
+        event = {
+            "project_id": project_id,
+            "node_id": node_id,
+            "link_id": signal_link or link_id,
+            "filter": filter_name,
+            # Prefer the value carried in the signal; fall back to the one we registered.
+            "tag": tag if tag and tag != "-" else registered_tag,
+            "ts": ts,
+            "len": int(length) if length and length.isdigit() else 0,
+        }
+        self._manager.emit_match(project_id, event)

gns3server/compute/marker/marker_manager.py

@@ -0,0 +1,185 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2024 GNS3 Technologies Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import asyncio
+import logging
+
+from gns3server.compute.marker.marker_listener import MarkerListener
+from gns3server.compute.notification_manager import NotificationManager
+
+log = logging.getLogger(__name__)
+
+
+class MarkerManager:
+    """
+    Singleton owning the compute-side UDP sink for ubridge ``MARK`` signals and
+    the registry that maps each ``(node_id, filter_name)`` back to its
+    ``(project_id, link_id, tag)``.
+
+    The registry is populated when a marker is created on a link (the compute
+    endpoint has project_id + node_id from its route path and link_id/name/tag
+    from the request body) and cleared when the marker is deleted or the project
+    closed. At signal time it is an O(1) lookup — no node-table scan, and the
+    signal payload is untouched.
+
+    One listener per compute process serves every ubridge on that host; source
+    ubridges are disambiguated by ``node=<id>`` (UUID, globally unique).
+    """
+
+    def __init__(self):
+
+        self._listener = None
+        self._transport = None
+        self._host = None
+        self._port = None
+        # Flat lookup: (node_id, filter_name) -> {"project_id", "link_id", "tag"}
+        self._entries = {}
+        # Reverse index for O(1) per-project teardown: project_id -> set of keys
+        self._by_project = {}
+
+    @property
+    def host(self):
+        """The host the UDP sink is reachable on (for ``marker sink``)."""
+        return self._host
+
+    @property
+    def port(self):
+        """The UDP port the sink is bound on (for ``marker sink``)."""
+        return self._port
+
+    @property
+    def running(self):
+        return self._transport is not None
+
+    async def start(self, host="127.0.0.1", port=0):
+        """
+        Bind the UDP sink. ``port=0`` lets the OS choose a free port, which is
+        then read back and exposed via :attr:`port` for ``marker sink`` commands.
+        """
+
+        if self.running:
+            return
+        loop = asyncio.get_running_loop()
+        self._listener = MarkerListener(self)
+        try:
+            self._transport, _ = await loop.create_datagram_endpoint(
+                lambda: self._listener, local_addr=(host, port)
+            )
+        except OSError:
+            if port != 0:
+                log.warning(
+                    "Marker listener: port %s unavailable, falling back to OS-assigned port", port
+                )
+                try:
+                    self._transport, _ = await loop.create_datagram_endpoint(
+                        lambda: self._listener, local_addr=(host, 0)
+                    )
+                except OSError as e:
+                    log.error(
+                        "Marker listener startup failed: %s. Traffic insight signals are unavailable.", e
+                    )
+                    self._listener = None
+                    return
+            else:
+                log.error(
+                    "Marker listener startup failed on OS-assigned port. Traffic insight signals are unavailable."
+                )
+                self._listener = None
+                return
+        sock = self._transport.get_extra_info("socket")
+        self._host = host
+        self._port = sock.getsockname()[1] if sock else port
+        log.info("Marker signal sink listening on %s:%s", self._host, self._port)
+
+    async def stop(self):
+        """Close the UDP sink and drop the whole registry."""
+
+        if self._transport:
+            self._transport.close()
+            self._transport = None
+        self._listener = None
+        self._entries.clear()
+        self._by_project.clear()
+        self._host = None
+        self._port = None
+
+    def register(self, project_id, node_id, filter_name, link_id, tag=None):
+        """
+        Record that ``filter_name`` on ``node_id`` belongs to ``project_id`` /
+        ``link_id``. Called from the compute marker-start endpoint.
+
+        Re-registering the same key updates the stored tag (e.g. on re-add).
+        """
+
+        key = (node_id, filter_name)
+        self._entries[key] = {"project_id": project_id, "link_id": link_id, "tag": tag}
+        self._by_project.setdefault(project_id, set()).add(key)
+
+    def unregister(self, node_id, filter_name):
+        """Forget a single marker. Returns True if something was removed."""
+
+        key = (node_id, filter_name)
+        entry = self._entries.pop(key, None)
+        if entry is None:
+            return False
+        project_entries = self._by_project.get(entry["project_id"])
+        if project_entries is not None:
+            project_entries.discard(key)
+            if not project_entries:
+                self._by_project.pop(entry["project_id"], None)
+        return True
+
+    def unregister_project(self, project_id):
+        """Drop every marker belonging to ``project_id`` (project close)."""
+
+        keys = self._by_project.pop(project_id, None)
+        if not keys:
+            return
+        for key in keys:
+            self._entries.pop(key, None)
+
+    def lookup(self, node_id, filter_name):
+        """
+        O(1) resolution of an incoming signal to its project/link/tag.
+
+        :returns: (project_id, link_id, tag) or (None, None, None) on miss.
+        """
+
+        entry = self._entries.get((node_id, filter_name))
+        if entry is None:
+            return None, None, None
+        return entry["project_id"], entry["link_id"], entry["tag"]
+
+    def emit_match(self, project_id, event):
+        """
+        Forward a parsed match as a project-scoped ``marker.match`` notification.
+        Flows compute -> controller dispatch -> project_emit -> web UI WS.
+        """
+
+        NotificationManager.instance().emit("marker.match", event, project_id=project_id)
+
+    _instance = None
+
+    @staticmethod
+    def instance():
+        if MarkerManager._instance is None:
+            MarkerManager._instance = MarkerManager()
+        return MarkerManager._instance
+
+    @staticmethod
+    def reset():
+        MarkerManager._instance = None

gns3server/compute/nios/nio.py

@@ -30,6 +30,7 @@ class NIO:
         self._capturing = False
         self._suspended = False
         self._filters = {}
+        self._markers = {}
         self._pcap_output_file = ""
         self._pcap_data_link_type = ""
 
@@ -118,3 +119,24 @@ class NIO:
 
         assert isinstance(new_filters, dict)
         self._filters = new_filters
+
+    @property
+    def markers(self):
+        """
+        Returns the traffic-insight markers for this NIO.
+
+        :returns: markers (dictionary: name -> {bpf, tag, link_id})
+        """
+
+        return self._markers
+
+    @markers.setter
+    def markers(self, new_markers):
+        """
+        Set the traffic-insight markers for this NIO.
+
+        :param new_markers: markers (dictionary: name -> {bpf, tag, link_id})
+        """
+
+        assert isinstance(new_markers, dict)
+        self._markers = new_markers

gns3server/compute/nios/nio_udp.py

@@ -80,5 +80,6 @@ class NIOUDP(NIO):
             "rport": self._rport,
             "rhost": self._rhost,
             "suspend": self._suspended,
-            "filters": self._filters
+            "filters": self._filters,
+            "markers": self._markers
         }

gns3server/compute/project.py

@@ -246,6 +246,22 @@ class Project:
                 raise ComputeError(f"Could not create the capture working directory: {e}")
         return workdir
 
+    def markers_working_directory(self):
+        """
+        Returns the working directory where uBridge writes per-link marker pcaps
+        (matched packets, kept for later replay).
+
+        :returns: path to the directory
+        """
+
+        workdir = os.path.join(self._path, "project-files", "markers")
+        if not self._deleted:
+            try:
+                os.makedirs(workdir, exist_ok=True)
+            except OSError as e:
+                raise ComputeError(f"Could not create the markers working directory: {e}")
+        return workdir
+
     def add_node(self, node):
         """
         Adds a node to the project.

gns3server/config_samples/gns3_server.conf

@@ -92,6 +92,13 @@ udp_end_port_range = 30000
 ; uBridge executable location, default: search in PATH
 ;ubridge_path = ubridge
 
+; Marker (traffic-insight) UDP sink: one listener per compute process that
+; receives uBridge MARK signals from every uBridge on this host.
+; marker_listen_host defaults to 127.0.0.1 because uBridge runs locally.
+; marker_listen_port defaults to 3070 (set to 0 for OS-chosen).
+;marker_listen_host = 127.0.0.1
+;marker_listen_port = 3070
+
 ; Option to enable or disable compute HTTP authentication
 enable_http_auth = True
 

gns3server/controller/__init__.py

@@ -741,6 +741,9 @@ class Controller:
         topo_data.pop("version")
         topo_data.pop("revision")
         topo_data.pop("type")
+        # marker_definitions is restored by Project.open() from the topology
+        # file; it must not be passed to Project.__init__.
+        topo_data.pop("marker_definitions", None)
 
         if topo_data["project_id"] in self._projects:
             project = self._projects[topo_data["project_id"]]

gns3server/controller/link.py

@@ -88,6 +88,7 @@ class Link:
         self._link_type = "ethernet"
         self._suspended = False
         self._filters = {}
+        self._markers = {}
         self._link_style = {}
         self._wireshark = False
         self._show_filters_icon = True
@@ -99,6 +100,40 @@ class Link:
         """
         return self._filters
 
+    @property
+    def markers(self):
+        """
+        Get the traffic insight markers dict: name → {bpf, tag, enabled}
+        """
+        return self._markers
+
+    async def inherit_marker(self, def_name, marker_def):
+        """
+        Apply a project-level marker definition to this link.
+
+        The marker is stored under ``global-{def_name}`` so it cannot collide
+        with a per-link private marker of the same name.  It carries an
+        ``inherited_from`` back-reference that (a) guards against per-link
+        edits and (b) lets the project sync changes to every copy at once.
+        """
+
+        await self.start_marker(
+            name=f"global-{def_name}",
+            bpf=marker_def["bpf"],
+            tag=marker_def.get("tag"),
+            color=marker_def.get("color"),
+            highlight_duration=marker_def.get("highlight_duration"),
+            inherited_from=def_name,
+        )
+
+    def _persist_markers(self):
+        """
+        Return only the per-link (non-inherited) markers suitable for
+        persistence in a topology dump.  Inherited markers are re-created from
+        ``project._marker_definitions`` on load so they do not need to be saved.
+        """
+        return {k: v for k, v in self._markers.items() if not v.get("inherited_from")}
+
     @property
     def show_filters_icon(self):
         """
@@ -298,6 +333,27 @@ class Link:
 
         raise NotImplementedError
 
+    async def start_marker(self, name, bpf, tag=None):
+        """
+        Attach a traffic-insight marker to this link (base — UDPLink overrides).
+        """
+        raise NotImplementedError
+
+    async def stop_marker(self, name):
+        """
+        Remove a traffic-insight marker from this link (base — UDPLink overrides).
+        """
+        raise NotImplementedError
+
+    async def update_marker(self, name, bpf=None, tag=None, enabled=None):
+        """
+        Update an existing marker's BPF, tag, or enabled flag.
+
+        A BPF change is a delete+re-add on the ubridge side so the pcap is
+        flushed and the new filter takes effect.
+        """
+        raise NotImplementedError
+
     async def start_capture(self, data_link_type="DLT_EN10MB", capture_file_name=None, wireshark=False, jwt_token=None):
         """
         Start capture on the link
@@ -571,6 +627,7 @@ class Link:
                 "nodes": res,
                 "link_id": self._id,
                 "filters": self._filters,
+                "markers": self._persist_markers(),
                 "link_style": self._link_style,
                 "suspend": self._suspended,
                 "show_filters_icon": getattr(self, '_show_filters_icon', True),
@@ -585,6 +642,7 @@ class Link:
             "capture_compute_id": self.capture_compute_id,
             "link_type": self._link_type,
             "filters": self._filters,
+            "markers": self._markers,
             "suspend": self._suspended,
             "link_style": self._link_style,
             "wireshark": self._wireshark,

gns3server/controller/project.py

@@ -41,6 +41,7 @@ from ..config import Config
 from ..utils.path import check_path_allowed, get_default_project_directory
 from ..utils.application_id import get_next_application_id
 from ..utils.asyncio.pool import Pool
+from ..utils.packet_filter_validation import validate_bpf_syntax
 from ..utils.asyncio import locking
 from ..utils.asyncio import aiozipstream
 from ..utils.asyncio import wait_run_in_executor
@@ -211,6 +212,7 @@ class Project:
         self._allocated_node_names = set()
         self._nodes = {}
         self._links = {}
+        self._marker_definitions = {}  # name → {bpf, tag, color, highlight_duration}
         self._drawings = {}
         self._snapshots = {}
         self._computes = []
@@ -765,6 +767,31 @@ class Project:
                     "Dropping invalid filters on link %s: %s",
                     link_data.get("link_id"), e
                 )
+        # Restore traffic-insight markers directly into link state (mirrors how
+        # filters are restored via update_filters). The capture_node_id persisted
+        # last time is reused for NIO routing; no side resolution is possible here
+        # because the link's nodes are added later. The marker is applied to
+        # uBridge by _ubridge_apply_markers when create() runs. Invalid BPF is
+        # dropped (like invalid filters).
+        for name, marker in (link_data.get("markers") or {}).items():
+            bpf = marker.get("bpf")
+            if not bpf:
+                log.warning("Dropping marker %s on link %s: missing bpf", name, link_data.get("link_id"))
+                continue
+            result = validate_bpf_syntax(bpf)
+            if not result.get("valid"):
+                log.warning(
+                    "Dropping marker %s on link %s: invalid BPF (%s)",
+                    name, link_data.get("link_id"), result.get("error")
+                )
+                continue
+            link._markers[name] = {
+                "bpf": bpf,
+                "tag": marker.get("tag"),
+                "enabled": marker.get("enabled", True),
+                "color": marker.get("color"),
+                "capture_node_id": marker.get("capture_node_id"),
+            }
         if "link_style" in link_data:
             await link.update_link_style(link_data["link_style"])
         if "show_filters_icon" in link_data:
@@ -872,6 +899,146 @@ class Project:
             return self._get_closed_data("links", "link_id")
         return self._links
 
+    @property
+    def markers(self):
+        """
+        Project-level read-only aggregation of all markers across every link.
+
+        Each entry is keyed ``"{link_id}/{marker_name}"`` so the flat dict is
+        globally unique within the project.  The value is a clone of the link's
+        per-marker dict plus ``link_id`` and ``node_id`` (the capture-side node)
+        for convenience — the frontend can filter/group by link or node without
+        extra round-trips.
+
+        :returns: dict[str, dict] — keyed by "{link_id}/{marker_name}"
+        """
+        result = {}
+        for link_id, link in self._links.items():
+            for name, info in link.markers.items():
+                key = f"{link_id}/{name}"
+                result[key] = {
+                    **info,
+                    "link_id": link_id,
+                    "node_id": info.get("capture_node_id"),
+                }
+        return result
+
+    @property
+    def marker_definitions(self):
+        """
+        :returns: dict of project-level marker definitions (name → {bpf, tag, color, highlight_duration})
+        """
+        return self._marker_definitions
+
+    async def create_marker_definition(self, name, bpf, tag=None, color=None, highlight_duration=None):
+        """
+        Create a project-level marker definition and fan out to every existing
+        link that has a capable node.  Links without a capable node are silently
+        skipped.
+        """
+
+        if name in self._marker_definitions:
+            raise ControllerError(
+                f"Marker definition '{name}' already exists in this project"
+            )
+
+        self._marker_definitions[name] = {"bpf": bpf, "tag": tag, "color": color, "highlight_duration": highlight_duration}
+        await self._apply_def_to_all_links(name)
+        self.dump()
+        self.emit_notification("project.updated", self.asdict())
+
+    async def update_marker_definition(self, name, bpf=None, tag=None, color=None, highlight_duration=None):
+        """
+        Update a marker definition and sync every inherited copy on every link.
+        """
+
+        if name not in self._marker_definitions:
+            raise ControllerNotFoundError(
+                f"Marker definition '{name}' not found in this project"
+            )
+
+        d = self._marker_definitions[name]
+        if bpf is not None:
+            d["bpf"] = bpf
+        if tag is not None:
+            d["tag"] = tag
+        if color is not None:
+            d["color"] = color
+        if highlight_duration is not None:
+            d["highlight_duration"] = highlight_duration
+
+        # Sync: update every inherited copy across all links.
+        for link in list(self._links.values()):
+            marker_name = f"global-{name}"
+            if marker_name in link.markers and link.markers[marker_name].get("inherited_from") == name:
+                await link.update_marker(
+                    marker_name, bpf=d["bpf"], tag=d.get("tag"), color=d.get("color"),
+                    highlight_duration=d.get("highlight_duration"), inherited=True
+                )
+        self.dump()
+        self.emit_notification("project.updated", self.asdict())
+
+    async def delete_marker_definition(self, name):
+        """
+        Delete a marker definition and remove every inherited copy from every link.
+        """
+
+        if name not in self._marker_definitions:
+            raise ControllerNotFoundError(
+                f"Marker definition '{name}' not found in this project"
+            )
+
+        del self._marker_definitions[name]
+
+        for link in list(self._links.values()):
+            marker_name = f"global-{name}"
+            if marker_name in link.markers and link.markers[marker_name].get("inherited_from") == name:
+                try:
+                    await link.stop_marker(marker_name, inherited=True)
+                except ControllerError:
+                    # A missing compute or broken link shouldn't block the delete.
+                    log.warning(
+                        "Failed to remove inherited marker %s from link %s",
+                        marker_name, link.id
+                    )
+
+        self.dump()
+        self.emit_notification("project.updated", self.asdict())
+
+    async def _apply_def_to_all_links(self, def_name):
+        """
+        Fan out a single marker definition to every existing link in the project.
+        Links that have no capable node (``_MARKER_CAPABLE_TYPES``) are silently
+        skipped — the marker can only live on a uBridge bridge.
+        """
+
+        d = self._marker_definitions[def_name]
+        for link in list(self._links.values()):
+            try:
+                await link.inherit_marker(def_name, d)
+            except ControllerError as e:
+                # Per-link failures (e.g. no capable node) shouldn't block the
+                # definition from serving the rest.
+                log.warning(
+                    "Marker definition '%s' could not be applied to link %s: %s",
+                    def_name, link.id, e
+                )
+
+    async def apply_defs_to_new_link(self, link):
+        """
+        Apply every active marker definition to a newly created link so it
+        inherits project-level rules automatically.
+        """
+
+        for def_name, d in self._marker_definitions.items():
+            try:
+                await link.inherit_marker(def_name, d)
+            except ControllerError as e:
+                log.warning(
+                    "Marker definition '%s' could not be applied to new link %s: %s",
+                    def_name, link.id, e
+                )
+
     @property
     def snapshots(self):
         """
@@ -1262,6 +1429,12 @@ class Project:
                 if val is not None:
                     setattr(self, key, val)
 
+            # marker_definitions is loaded separately (it is not a __init__ kwarg
+            # nor a simple attribute — it backs a read-only property).
+            defs = project_data.get("marker_definitions")
+            if isinstance(defs, dict):
+                self._marker_definitions = defs
+
             topology = project_data["topology"]
             for compute in topology.get("computes", []):
                 compute_id = compute.get("compute_id")
@@ -1328,6 +1501,10 @@ class Project:
             for drawing_data in topology.get("drawings", []):
                 await self.add_drawing(dump=False, **drawing_data)
 
+            # Note: project-level marker definitions are applied to each link
+            # inside UDPLink.create() (the inheritance hook), so they are
+            # already present once links are loaded — no separate fan-out here.
+
             self.dump()
         # We catch all error to be able to roll back the .gns3 to the previous state
         except Exception as e:
@@ -1684,6 +1861,7 @@ class Project:
             "links": len(self._links),
             "drawings": len(self._drawings),
             "snapshots": len(self._snapshots),
+            "markers": sum(len(link.markers) for link in self._links.values()),
         }
 
     def asdict(self):
@@ -1708,6 +1886,7 @@ class Project:
             "supplier": self._supplier,
             "variables": self._variables,
             "created_by": self._created_by,
+            "marker_definitions": self._marker_definitions,
         }
 
     def __repr__(self):

gns3server/controller/topology.py

@@ -88,6 +88,7 @@ def project_to_topology(project):
         "variables": project.variables,
         "supplier": project.supplier,
         "created_by": project.created_by,
+        "marker_definitions": project.marker_definitions,
         "topology": {"nodes": [], "links": [], "computes": [], "drawings": []},
         "type": "topology",
         "revision": GNS3_FILE_FORMAT_REVISION,

gns3server/controller/udp_link.py

@@ -19,6 +19,15 @@
 from .controller_error import ControllerError, ControllerNotFoundError
 from .link import Link
 from .node_types import BUILTIN_NODE_TYPES
+from gns3server.utils.packet_filter_validation import validate_bpf_syntax, FilterValidationError
+
+# Node types without a uBridge bridge — a marker filter has nothing to attach to.
+# Node types that can host a marker (have a uBridge bridge to attach the
+# `mark` filter to).  Mirrors _get_filter_node in link.py, minus "nat"
+# (which has no uBridge).
+_MARKER_CAPABLE_TYPES = frozenset({
+    "vpcs", "qemu", "docker", "iou", "dynamips", "cloud",
+})
 
 
 class UDPLink(Link):
@@ -37,7 +46,7 @@ class UDPLink(Link):
     def _get_node_filters(self, node1, node2):
         """
         Determine which node gets the active filters applied.
-        
+
         :returns: Tuple of (node1_filters, node2_filters)
         """
         filter_node = self._get_filter_node()
@@ -46,6 +55,26 @@ class UDPLink(Link):
             self.get_active_filters() if filter_node == node2 else {},
         )
 
+    def _markers_for_node(self, node):
+        """
+        Marker specs (name -> {bpf, tag, link_id}) for the markers whose capture
+        side is ``node`` and that are enabled. Routed by capture_node_id so a
+        marker only rides the NIO of the node whose uBridge will host it.
+        """
+        return {
+            name: {"bpf": m["bpf"], "tag": m.get("tag"), "link_id": self._id}
+            for name, m in self._markers.items()
+            if m.get("enabled", True) and m.get("capture_node_id") == node.id
+        }
+
+    def _get_node_markers(self, node1, node2):
+        """
+        Determine which node gets which markers applied.
+
+        :returns: Tuple of (node1_markers, node2_markers)
+        """
+        return self._markers_for_node(node1), self._markers_for_node(node2)
+
     async def create(self):
         """
         Create the link on the nodes
@@ -80,6 +109,7 @@ class UDPLink(Link):
             self._node2_port = response.json["udp_port"]
 
         node1_filters, node2_filters = self._get_node_filters(node1, node2)
+        node1_markers, node2_markers = self._get_node_markers(node1, node2)
 
         # Create the tunnel on both side
         self._link_data.append(
@@ -89,6 +119,7 @@ class UDPLink(Link):
                 "rport": self._node2_port,
                 "type": "nio_udp",
                 "filters": node1_filters,
+                "markers": node1_markers,
                 "suspend": self._suspended,
             }
         )
@@ -101,6 +132,7 @@ class UDPLink(Link):
                 "rport": self._node1_port,
                 "type": "nio_udp",
                 "filters": node2_filters,
+                "markers": node2_markers,
                 "suspend": self._suspended,
             }
         )
@@ -113,6 +145,9 @@ class UDPLink(Link):
             await node1.delete(f"/adapters/{adapter_number1}/ports/{port_number1}/nio", timeout=120)
             raise e
         self._created = True
+        # New links automatically inherit every active project-level marker
+        # definition so the user doesn't have to reconfigure.
+        await self._project.apply_defs_to_new_link(self)
 
     async def update(self):
         """
@@ -125,10 +160,12 @@ class UDPLink(Link):
         node2 = self._nodes[1]["node"]
 
         node1_filters, node2_filters = self._get_node_filters(node1, node2)
+        node1_markers, node2_markers = self._get_node_markers(node1, node2)
 
         adapter_number1 = self._nodes[0]["adapter_number"]
         port_number1 = self._nodes[0]["port_number"]
         self._link_data[0]["filters"] = node1_filters
+        self._link_data[0]["markers"] = node1_markers
         self._link_data[0]["suspend"] = self._suspended
         if node1.node_type not in ("ethernet_switch", "ethernet_hub"):
             await node1.put(
@@ -138,6 +175,7 @@ class UDPLink(Link):
         adapter_number2 = self._nodes[1]["adapter_number"]
         port_number2 = self._nodes[1]["port_number"]
         self._link_data[1]["filters"] = node2_filters
+        self._link_data[1]["markers"] = node2_markers
         self._link_data[1]["suspend"] = self._suspended
         if node2.node_type not in ("ethernet_switch", "ethernet_hub"):
             await node2.put(
@@ -245,9 +283,161 @@ class UDPLink(Link):
 
         raise ControllerError("Cannot capture because there is no running device on this link")
 
+    def _choose_marker_side(self):
+        """
+        Pick the node that will host the marker, mirroring ``_get_filter_node``
+        in link.py.  Only types with a uBridge bridge (``_MARKER_CAPABLE_TYPES``)
+        are eligible.  A running node is preferred, but a stopped one is
+        accepted — like packet filters, the marker is stored on the NIO and
+        applied when the node starts.
+        """
+
+        # Prefer started.
+        for node in self._nodes:
+            if (
+                node["node"].node_type in _MARKER_CAPABLE_TYPES
+                and node["node"].status == "started"
+            ):
+                return node
+
+        # Accept stopped but capable (marker rides NIO, applied at start).
+        for node in self._nodes:
+            if node["node"].node_type in _MARKER_CAPABLE_TYPES:
+                return node
+
+        raise ControllerError(
+            "Cannot add marker because no device on this link supports "
+            "traffic insight"
+        )
+
     async def node_updated(self, node):
         """
         Called when a node member of the link is updated
         """
         if self._capture_node and node == self._capture_node["node"] and node.status != "started":
             await self.stop_capture()
+        # Marker clean-up is *not* done on node stop — markers are a persistent
+        # link-scoped feature that recovers via NIO on restart (see
+        # _ubridge_apply_markers in add_ubridge_udp_connection).  The user
+        # explicitly deletes a marker via the REST API, and a marker is torn
+        # down automatically only when its link is deleted.
+
+    async def start_marker(self, name, bpf, tag=None, color=None, highlight_duration=None, inherited_from=None):
+        """
+        Attach a traffic-insight marker to this link.
+
+        State-only model (mirrors ``update_filters``): record the marker in
+        ``_markers`` (with its capture-side node id for NIO routing), then push
+        via ``self.update()`` so it rides the NIO and is applied by
+        ``_ubridge_apply_markers``. No dedicated uBridge round-trip — exactly
+        how packet filters are applied.
+
+        :param name: stable filter name — echoed in MARK signals + pcap identity
+        :param bpf: libpcap BPF expression
+        :param tag: optional correlation id
+        :param color: optional hex color for the Web UI (e.g. '#ff5722'); stored
+            with the link and persisted in the topology, never sent to uBridge
+        :param highlight_duration: optional UI-only hint (milliseconds) for how
+            long a match keeps the marker highlighted; stored, never sent to uBridge
+        :param inherited_from: def name when this marker is a project-level
+            inheritance copy; set automatically, never exposed to REST callers
+        """
+
+        if name in self._markers:
+            raise ControllerError(f"Marker '{name}' already exists on link {self._id}")
+
+        result = validate_bpf_syntax(bpf)
+        if not result.get("valid"):
+            raise ControllerError(f"Invalid BPF expression: {result.get('error', 'unknown error')}")
+
+        marker_side = self._choose_marker_side()
+        marker_entry = {
+            "bpf": bpf,
+            "tag": tag,
+            "enabled": True,
+            "color": color,
+            "highlight_duration": highlight_duration,
+            "capture_node_id": marker_side["node"].id,
+        }
+        if inherited_from:
+            marker_entry["inherited_from"] = inherited_from
+        self._markers[name] = marker_entry
+        if self._created:
+            await self.update()
+        self._project.emit_notification("link.updated", self.asdict())
+        self._project.dump()
+
+    async def stop_marker(self, name, inherited=False):
+        """
+        Remove a traffic-insight marker from this link.
+
+        Drop it from ``_markers`` and push via ``self.update()``: the NIO
+        reset+reapply in ``_ubridge_apply_filters``/``_ubridge_apply_markers``
+        drops it from uBridge. Mirrors how deleting a packet filter works.
+
+        :param name: filter name to remove
+        :param inherited: set by project-level def-delete to bypass the
+            inheritance guard (the project layer is the legitimate remover)
+        """
+
+        if name not in self._markers:
+            raise ControllerNotFoundError(f"Marker '{name}' not found on link {self._id}")
+
+        if self._markers[name].get("inherited_from") and not inherited:
+            raise ControllerError(
+                f"Marker '{name}' is inherited from the project-level "
+                f"definition '{self._markers[name]['inherited_from']}'. "
+                "Delete or update it via the marker-definitions API instead."
+            )
+
+        del self._markers[name]
+        if self._created:
+            await self.update()
+        self._project.emit_notification("link.updated", self.asdict())
+        self._project.dump()
+
+    async def update_marker(self, name, bpf=None, tag=None, enabled=None, color=None, highlight_duration=None, inherited=False):
+        """
+        Update an existing marker's BPF/tag/enabled/color. Any change pushes via
+        ``self.update()``; uBridge picks up the new params on the next NIO
+        reset+reapply (same as packet filters).
+
+        :param name: filter name to update
+        :param bpf: new BPF expression (None = keep existing)
+        :param tag: new tag id (None = keep existing)
+        :param enabled: toggle (None = keep existing)
+        :param color: new hex color (None = keep existing)
+        :param highlight_duration: new UI highlight duration in ms (None = keep existing)
+        :param inherited: set by project-level sync to bypass the inheritance
+            guard (the project layer is the legitimate editor)
+        """
+
+        marker_info = self._markers.get(name)
+        if not marker_info:
+            raise ControllerNotFoundError(f"Marker '{name}' not found on link {self._id}")
+
+        if marker_info.get("inherited_from") and not inherited:
+            raise ControllerError(
+                f"Marker '{name}' is inherited from the project-level "
+                f"definition '{marker_info['inherited_from']}'. "
+                "Update it via the marker-definitions API instead."
+            )
+
+        if bpf is not None and bpf != marker_info["bpf"]:
+            result = validate_bpf_syntax(bpf)
+            if not result.get("valid"):
+                raise ControllerError(f"Invalid BPF expression: {result.get('error', 'unknown error')}")
+            marker_info["bpf"] = bpf
+        if tag is not None:
+            marker_info["tag"] = tag
+        if enabled is not None:
+            marker_info["enabled"] = enabled
+        if color is not None:
+            marker_info["color"] = color
+        if highlight_duration is not None:
+            marker_info["highlight_duration"] = highlight_duration
+
+        if self._created:
+            await self.update()
+        self._project.emit_notification("link.updated", self.asdict())
+        self._project.dump()

gns3server/core/tasks.py

@@ -24,6 +24,7 @@ from gns3server.controller import Controller
 from gns3server.config import Config
 from gns3server.compute import MODULES
 from gns3server.compute.port_manager import PortManager
+from gns3server.compute.marker.marker_manager import MarkerManager
 from gns3server.utils.http_client import HTTPClient
 from gns3server.db.tasks import connect_to_db, get_computes, disconnect_from_db, discover_images_on_filesystem
 
@@ -84,6 +85,14 @@ async def startup(app: FastAPI) -> None:
         m = module.instance()
         m.port_manager = PortManager.instance()
 
+    # Start the marker (traffic-insight) UDP sink. One listener per compute
+    # process receives ubridge MARK signals; ubridges are told its host/port at
+    # startup (see BaseNode._start_ubridge).
+    server_settings = Config.instance().settings.Server
+    await MarkerManager.instance().start(
+        host=server_settings.marker_listen_host, port=server_settings.marker_listen_port
+    )
+
     # Mark MCP server as ready to accept connections (if MCP is available)
     from gns3server.agent import MCP_AVAILABLE
 
@@ -101,6 +110,7 @@ async def shutdown(app: FastAPI) -> None:
     if auto_discover_images_task_handle is not None and not auto_discover_images_task_handle.cancelled():
         auto_discover_images_task_handle.cancel()
     await HTTPClient.close_session()
+    await MarkerManager.instance().stop()
     await Controller.instance().stop()
 
     for module in MODULES:

gns3server/schemas/__init__.py

@@ -20,7 +20,7 @@ from .common import ErrorMessage
 from .version import Version
 
 # Controller schemas
-from .controller.links import LinkCreate, LinkUpdate, Link, UDPPortInfo, EthernetPortInfo, LinkCapture
+from .controller.links import LinkCreate, LinkUpdate, Link, UDPPortInfo, EthernetPortInfo, LinkCapture, MarkerCreate, MarkerDefinitionCreate
 from .controller.computes import ComputeCreate, ComputeUpdate, ComputeVirtualBoxVM, ComputeVMwareVM, ComputeDockerImage, AutoIdlePC, Compute
 from .controller.templates import TemplateCreate, TemplateUpdate, TemplateUsage, Template
 from .controller.images import Image, ImageType

gns3server/schemas/compute/nios.py

@@ -36,6 +36,7 @@ class UDPNIO(BaseModel):
     rport: int = Field(..., gt=0, le=65535, description="Remote port")
     suspend: Optional[bool] = Field(None, description="Suspend the NIO")
     filters: Optional[dict] = Field(None, description="Packet filters")
+    markers: Optional[dict] = Field(None, description="Traffic-insight markers")
 
 
 class EthernetNIOType(str, Enum):

gns3server/schemas/config.py

@@ -153,6 +153,12 @@ class ServerSettings(BaseModel):
     udp_start_port_range: int = Field(10000, gt=0, le=65535)
     udp_end_port_range: int = Field(30000, gt=0, le=65535)
     ubridge_path: str = "ubridge"
+    # Marker (traffic-insight) UDP sink: one listener per compute process that
+    # receives ubridge MARK signals from every ubridge on this host. The host
+    # defaults to loopback because ubridge runs on the same host as the compute.
+    # port=0 lets the OS choose a free port (read back and handed to ubridge).
+    marker_listen_host: str = "127.0.0.1"
+    marker_listen_port: int = Field(3070, ge=0, le=65535)
     compute_username: str = "gns3"
     compute_password: SecretStr = SecretStr("")
     allowed_interfaces: List[str] = Field(default_factory=list)

gns3server/schemas/controller/links.py

@@ -62,6 +62,10 @@ class LinkBase(BaseModel):
     suspend: Optional[bool] = None
     link_style: Optional[LinkStyle] = None
     filters: Optional[dict] = None
+    markers: Optional[dict] = Field(
+        None,
+        description="Traffic-insight markers on this link: name → {bpf, tag, enabled}"
+    )
     show_filters_icon: Optional[bool] = Field(
         True,
         description="Show filters icon in Web UI"
@@ -135,3 +139,73 @@ class LinkCapture(BaseModel):
     data_link_type: str = "DLT_EN10MB"
     capture_file_name: Optional[str] = None
     wireshark: bool = False
+
+
+class MarkerCreate(BaseModel):
+    """
+    Body for attaching a traffic-insight marker to a link.
+
+    ``name`` is optional at the controller REST layer (auto-generated when
+    absent) but always set when the controller forwards to the compute.
+    """
+
+    name: Optional[str] = Field(
+        None,
+        pattern=r"^[A-Za-z0-9][A-Za-z0-9_.-]*$",
+        max_length=128,
+        description='Unique marker name on the link. Auto-generated when absent.',
+    )
+    bpf: str
+    tag: Optional[int] = None
+    link_id: Optional[str] = None
+    color: Optional[str] = Field(
+        None,
+        description="User-chosen hex color for this marker in the Web UI, e.g. '#ff5722'",
+    )
+    highlight_duration: Optional[int] = Field(
+        None,
+        ge=1,
+        description=(
+            "How long (milliseconds) the Web UI keeps this marker highlighted "
+            "after a match. Omitted = use the UI default. Pure render hint — "
+            "stored on the link, never sent to uBridge."
+        ),
+    )
+    enabled: Optional[bool] = Field(
+        None,
+        description="Whether the marker is active. Defaults to true on creation.",
+    )
+
+
+class MarkerDefinitionCreate(BaseModel):
+    """
+    Body for creating / updating a project-level marker definition.
+
+    The definition is a template — when applied to a link the marker name is
+    prefixed with ``global-`` (e.g. ``arp`` → ``global-arp``) so it can never
+    collide with a per-link private marker.
+    """
+
+    name: Optional[str] = Field(
+        None,
+        pattern=r"^[A-Za-z0-9][A-Za-z0-9_.-]*$",
+        max_length=128,
+        description="Unique definition name. Auto-generated when absent.",
+    )
+    bpf: str
+    tag: Optional[int] = None
+    color: Optional[str] = Field(
+        None,
+        description="User-chosen hex color for the marker in the Web UI, e.g. '#ff5722'",
+    )
+    highlight_duration: Optional[int] = Field(
+        None,
+        ge=1,
+        description=(
+            "How long (milliseconds) the Web UI keeps this marker highlighted "
+            "after a match. Omitted = use the UI default. Pure render hint — "
+            "stored with the definition, never sent to uBridge."
+        ),
+    )
+
+