feat: add LLDP transmit support

.vscode/settings.json

@@ -10,5 +10,6 @@
     ]
   },
   "git.ignoreLimitWarning": true,
-  "cmake.sourceDirectory": "/workspaces/kvm-static-ip/internal/native/cgo"
+  "cmake.sourceDirectory": "/workspaces/kvm-static-ip/internal/native/cgo",
+  "cmake.ignoreCMakeListsMissing": true
 }

go.mod

@@ -64,6 +64,7 @@ require (
 	github.com/leodido/go-urn v1.4.0 // indirect
 	github.com/mattn/go-colorable v0.1.14 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mdlayher/ethernet v0.0.0-20220221185849-529eae5b6118 // indirect
 	github.com/mdlayher/packet v1.1.2 // indirect
 	github.com/mdlayher/socket v0.4.1 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect

go.sum

@@ -57,6 +57,8 @@ github.com/go-playground/validator/v10 v10.27.0/go.mod h1:I5QpIEbmr8On7W0TktmJAu
 github.com/goccy/go-json v0.10.5 h1:Fq85nIqj+gXn/S5ahsiTlK3TmC85qgirsdTP/+DeaC4=
 github.com/goccy/go-json v0.10.5/go.mod h1:oq7eo15ShAhp70Anwd5lgX2pLfOS3QCiwU/PULtXL6M=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
+github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
@@ -76,6 +78,7 @@ github.com/jellydator/ttlcache/v3 v3.4.0 h1:YS4P125qQS0tNhtL6aeYkheEaB/m8HCqdMMP
 github.com/jellydator/ttlcache/v3 v3.4.0/go.mod h1:Hw9EgjymziQD3yGsQdf1FqFdpp7YjFMd4Srg5EJlgD4=
 github.com/jonboulle/clockwork v0.5.0 h1:Hyh9A8u51kptdkR+cqRpT1EebBwTn1oK9YfGYbdFz6I=
 github.com/jonboulle/clockwork v0.5.0/go.mod h1:3mZlmanh0g2NDKO5TWZVJAfofYk64M7XN3SzBPjZF60=
+github.com/josharian/native v1.0.0/go.mod h1:7X/raswPFr05uY3HiLlYeyQntB6OO7E/d2Cu7qoaN2w=
 github.com/josharian/native v1.0.1-0.20221213033349-c1e37c09b531/go.mod h1:7X/raswPFr05uY3HiLlYeyQntB6OO7E/d2Cu7qoaN2w=
 github.com/josharian/native v1.1.0 h1:uuaP0hAbW7Y4l0ZRQ6C9zfb7Mg1mbFKry/xzDAfmtLA=
 github.com/josharian/native v1.1.0/go.mod h1:7X/raswPFr05uY3HiLlYeyQntB6OO7E/d2Cu7qoaN2w=
@@ -103,10 +106,14 @@ github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/
 github.com/mattn/go-isatty v0.0.19/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mdlayher/ethernet v0.0.0-20220221185849-529eae5b6118 h1:2oDp6OOhLxQ9JBoUuysVz9UZ9uI6oLUbvAZu0x8o+vE=
+github.com/mdlayher/ethernet v0.0.0-20220221185849-529eae5b6118/go.mod h1:ZFUnHIVchZ9lJoWoEGUg8Q3M4U8aNNWA3CVSUTkW4og=
 github.com/mdlayher/ndp v1.1.0 h1:QylGKGVtH60sKZUE88+IW5ila1Z/M9/OXhWdsVKuscs=
 github.com/mdlayher/ndp v1.1.0/go.mod h1:FmgESgemgjl38vuOIyAHWUUL6vQKA/pQNkvXdWsdQFM=
+github.com/mdlayher/packet v1.0.0/go.mod h1:eE7/ctqDhoiRhQ44ko5JZU2zxB88g+JH/6jmnjzPjOU=
 github.com/mdlayher/packet v1.1.2 h1:3Up1NG6LZrsgDVn6X4L9Ge/iyRyxFEFD9o6Pr3Q1nQY=
 github.com/mdlayher/packet v1.1.2/go.mod h1:GEu1+n9sG5VtiRE4SydOmX5GTwyyYlteZiFU+x0kew4=
+github.com/mdlayher/socket v0.2.1/go.mod h1:QLlNPkFR88mRUNQIzRBMfXxwKal8H7u1h3bL1CV+f0E=
 github.com/mdlayher/socket v0.4.1 h1:eM9y2/jlbs1M615oshPQOHZzj6R6wMT7bX5NPiQvn2U=
 github.com/mdlayher/socket v0.4.1/go.mod h1:cAqeGjoufqdxWkD7DkpyS+wcefOtmu5OQ8KuoJGIReA=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
@@ -217,16 +224,21 @@ golang.org/x/crypto v0.43.0/go.mod h1:BFbav4mRNlXJL4wNeejLpWxB7wMbc79PdRGhWKncxR
 golang.org/x/lint v0.0.0-20200302205851-738671d3881b/go.mod h1:3xt1FjdF8hUf6vQPIChWIBhFzV8gjjsPE/fR3IyQdNY=
 golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190503192946-f4e77d36d62c/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190603091049-60506f45cf65/go.mod h1:HSz+uSET+XFnRR8LxR5pz3Of3rY3CfYBVs4xY44aLks=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.46.0 h1:giFlY12I07fugqwPuWJi68oOnpfqFnJIJzaIIm2JVV4=
 golang.org/x/net v0.46.0/go.mod h1:Q9BGdFy1y4nkUwiLvT5qtyhAnEHgnQ/zd8PfU6nc210=
 golang.org/x/oauth2 v0.32.0 h1:jsCblLleRMDrxMN29H3z/k1KliIvpLgCkE6R8FXXNgY=
 golang.org/x/oauth2 v0.32.0/go.mod h1:lzm5WQJQwKZ3nwavOZ3IS5Aulzxi68dUSgRHujetwEA=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
 golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220209214540-3681064d5158/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220622161953-175b2fd9d664/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.2.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -242,6 +254,7 @@ golang.org/x/text v0.30.0 h1:yznKA/E9zq54KzlzBEAWn1NXSQ8DIp/NYMy88xJjl4k=
 golang.org/x/text v0.30.0/go.mod h1:yDdHFIX9t+tORqspjENWgzaCVXgk0yYnYuSZ8UzzBVM=
 golang.org/x/tools v0.0.0-20200130002326-2f3ba24bd6e7/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
 google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

internal/lldp/afpacket.go

@@ -16,9 +16,15 @@ const (
 	afPacketSnaplen    = 9216
 )
 
+// afpacketComputeSize computes the block_size and the num_blocks in such a way that the
+// allocated mmap buffer is close to but smaller than targetSizeMb.
+// The restriction is that the blockSize must be divisible by both the
+// frameSize and pageSize.
+//
+// See also: https://github.com/google/gopacket/blob/master/examples/afpacket/afpacket.go#L118
 func afPacketComputeSize(
 	targetSizeMb int,
-	snaplen int,
+	snapLen int,
 	pageSize int,
 ) (
 	frameSize int,
@@ -26,10 +32,17 @@ func afPacketComputeSize(
 	numBlocks int,
 	err error,
 ) {
-	if snaplen < pageSize {
+	if snapLen < pageSize {
-		frameSize = pageSize / (pageSize / snaplen)
+		// When snapLen < pageSize, find the largest value <= pageSize that
+		// is a multiple of snapLen and divides evenly into pageSize.
+		// This ensures frameSize is a divisor of pageSize.
+		// Example: snapLen=512, pageSize=4096 -> frameSize=512
+		// Example: snapLen=1000, pageSize=4096 -> frameSize=1024
+		frameSize = pageSize / (pageSize / snapLen)
 	} else {
-		frameSize = (snaplen/pageSize + 1) * pageSize
+		// When snapLen >= pageSize, round up to the next multiple of pageSize.
+		// Example: snapLen=9216, pageSize=4096 -> frameSize=12288 (3 pages)
+		frameSize = ((snapLen / pageSize) + 1) * pageSize
 	}
 
 	// 128 is the default from the gopacket library so just use that
@@ -37,7 +50,7 @@ func afPacketComputeSize(
 	numBlocks = (targetSizeMb * 1024 * 1024) / blockSize
 
 	if numBlocks == 0 {
-		return 0, 0, 0, fmt.Errorf("interface buffersize is too small")
+		return 0, 0, 0, fmt.Errorf("interface bufferSize is too small")
 	}
 
 	return frameSize, blockSize, numBlocks, nil

internal/lldp/lldp.go

@@ -1,6 +1,9 @@
 package lldp
 
 import (
+	"context"
+	"fmt"
+	"sync"
 	"time"
 
 	"github.com/google/gopacket"
@@ -13,30 +16,50 @@ import (
 var defaultLogger = logging.GetSubsystemLogger("lldp")
 
 type LLDP struct {
+	mu sync.RWMutex
+
 	l           *zerolog.Logger
-	tPacket   *afpacket.TPacket
+	tPacketRx   *afpacket.TPacket
-	pktSource *gopacket.PacketSource
+	tPacketTx   *afpacket.TPacket
+	pktSourceRx *gopacket.PacketSource
 
 	enableRx bool
 	enableTx bool
 
 	packets          chan gopacket.Packet
 	interfaceName    string
-	stop          chan struct{}
+	advertiseOptions *AdvertiseOptions
 	onChange         func(neighbors []Neighbor)
 
 	neighbors *ttlcache.Cache[string, Neighbor]
+
+	// State tracking
+	rxRunning bool
+	txRunning bool
+	txCtx     context.Context
+	txCancel  context.CancelFunc
+	rxCtx     context.Context
+	rxCancel  context.CancelFunc
 }
 
-type LLDPOptions struct {
+type AdvertiseOptions struct {
+	SysName             string
+	SysDescription      string
+	PortDescription     string
+	SysCapabilities     []string
+	EnabledCapabilities []string
+}
+
+type Options struct {
 	InterfaceName    string
+	AdvertiseOptions *AdvertiseOptions
 	EnableRx         bool
 	EnableTx         bool
 	OnChange         func(neighbors []Neighbor)
 	Logger           *zerolog.Logger
 }
 
-func NewLLDP(opts *LLDPOptions) *LLDP {
+func NewLLDP(opts *Options) *LLDP {
 	if opts.Logger == nil {
 		opts.Logger = defaultLogger
 	}
@@ -47,28 +70,76 @@ func NewLLDP(opts *LLDPOptions) *LLDP {
 
 	return &LLDP{
 		interfaceName:    opts.InterfaceName,
+		advertiseOptions: opts.AdvertiseOptions,
 		enableRx:         opts.EnableRx,
 		enableTx:         opts.EnableTx,
 		l:                opts.Logger,
 		neighbors:        ttlcache.New(ttlcache.WithTTL[string, Neighbor](1 * time.Hour)),
+		onChange:         opts.OnChange,
 	}
 }
 
 func (l *LLDP) Start() error {
-	if l.enableRx {
-		l.l.Info().Msg("setting up AF_PACKET")
-		if err := l.setUpCapture(); err != nil {
-			l.l.Error().Err(err).Msg("unable to set up AF_PACKET")
-			return err
-		}
-
-		if err := l.startCapture(); err != nil {
-			l.l.Error().Err(err).Msg("unable to start capture")
-			return err
-		}
-	}
-
 	go l.neighbors.Start()
 
+	if l.enableRx {
+		if err := l.startRx(); err != nil {
+			return fmt.Errorf("failed to start RX: %w", err)
+		}
+	}
+
+	// Start TX if enabled
+	if l.enableTx {
+		if err := l.startTx(); err != nil {
+			return fmt.Errorf("failed to start TX: %w", err)
+		}
+	}
+
+	return nil
+}
+
+// StartRx starts the LLDP receiver if not already running
+func (l *LLDP) startRx() error {
+	l.mu.Lock()
+	running := l.rxRunning
+	enabled := l.enableRx
+	l.mu.Unlock()
+
+	if running || !enabled {
+		return nil
+	}
+
+	if err := l.setUpCapture(); err != nil {
+		return fmt.Errorf("failed to set up capture: %w", err)
+	}
+
+	return l.startCapture()
+}
+
+// StopRx stops the LLDP receiver if running
+func (l *LLDP) StopRx() error {
+	return l.stopCapture()
+}
+
+// StopTx stops the LLDP transmitter if running
+func (l *LLDP) StopTx() error {
+	return l.stopTx()
+}
+
+// SetAdvertiseOptions updates the advertise options and resends LLDP packets if TX is running
+func (l *LLDP) SetAdvertiseOptions(opts *AdvertiseOptions) error {
+	l.mu.Lock()
+	txRunning := l.txRunning
+	l.advertiseOptions = opts
+	l.mu.Unlock()
+
+	if txRunning {
+		// Immediately resend with new options
+		if err := l.sendTxPackets(); err != nil {
+			return fmt.Errorf("failed to resend LLDP packet with new options: %w", err)
+		}
+		l.l.Info().Msg("advertise options changed, resent LLDP packet")
+	}
+
 	return nil
 }

internal/lldp/neigh.go

@@ -1,6 +1,19 @@
 package lldp
 
-import "time"
+import (
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+)
+
+type ManagementAddress struct {
+	AddressFamily    string `json:"address_family"`
+	Address          string `json:"address"`
+	InterfaceSubtype string `json:"interface_subtype"`
+	InterfaceNumber  uint32 `json:"interface_number"`
+	OID              string `json:"oid,omitempty"`
+}
 
 type Neighbor struct {
 	Mac               string             `json:"mac"`
@@ -11,17 +24,24 @@ type Neighbor struct {
 	SystemName        string             `json:"system_name"`
 	SystemDescription string             `json:"system_description"`
 	TTL               uint16             `json:"ttl"`
-	ManagementAddress string            `json:"management_address"`
+	ManagementAddress *ManagementAddress `json:"management_address,omitempty"`
+	Capabilities      []string           `json:"capabilities"`
 	Values            map[string]string  `json:"values"`
 }
 
-func (l *LLDP) addNeighbor(mac string, neighbor Neighbor, ttl time.Duration) {
+func (n *Neighbor) cacheKey() string {
+	return fmt.Sprintf("%s-%s", n.Mac, n.Source)
+}
+
+func (l *LLDP) addNeighbor(neighbor *Neighbor, ttl time.Duration) {
 	logger := l.l.With().
-		Str("mac", mac).
+		Str("mac", neighbor.Mac).
 		Interface("neighbor", neighbor).
 		Logger()
 
-	current_neigh := l.neighbors.Get(mac)
+	key := neighbor.cacheKey()
+
+	current_neigh := l.neighbors.Get(key)
 	if current_neigh != nil {
 		current_source := current_neigh.Value().Source
 		if current_source == "lldp" && neighbor.Source != "lldp" {
@@ -31,16 +51,16 @@ func (l *LLDP) addNeighbor(mac string, neighbor Neighbor, ttl time.Duration) {
 	}
 
 	logger.Info().Msg("adding neighbor")
-	l.neighbors.Set(mac, neighbor, ttl)
+	l.neighbors.Set(key, *neighbor, ttl)
 }
 
-func (l *LLDP) deleteNeighbor(mac string) {
+func (l *LLDP) deleteNeighbor(neighbor *Neighbor) {
 	logger := l.l.With().
-		Str("mac", mac).
+		Str("mac", neighbor.Mac).
 		Logger()
 
 	logger.Info().Msg("deleting neighbor")
-	l.neighbors.Delete(mac)
+	l.neighbors.Delete(neighbor.cacheKey())
 }
 
 func (l *LLDP) GetNeighbors() []Neighbor {
@@ -51,5 +71,10 @@ func (l *LLDP) GetNeighbors() []Neighbor {
 		neighbors = append(neighbors, item.Value())
 	}
 
+	// sort based on MAC address
+	sort.Slice(neighbors, func(i, j int) bool {
+		return strings.Compare(neighbors[i].Mac, neighbors[j].Mac) > 0
+	})
+
 	return neighbors
 }

internal/lldp/rx.go

@@ -1,6 +1,7 @@
 package lldp
 
 import (
+	"context"
 	"fmt"
 	"net"
 	"time"
@@ -27,12 +28,26 @@ var multicastAddrs = []string{
 }
 
 func (l *LLDP) setUpCapture() error {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+
+	if l.tPacketRx != nil {
+		return nil
+	}
+
 	logger := l.l.With().Str("interface", l.interfaceName).Logger()
-	tPacket, err := afPacketNewTPacket(l.interfaceName)
+	tPacketRx, err := afPacketNewTPacket(l.interfaceName)
 	if err != nil {
 		return err
 	}
-	logger.Info().Msg("created TPacket")
+	logger.Info().Msg("created TPacketRx")
+
+	// Double-check: another goroutine might have set it up while we were creating
+	if l.tPacketRx != nil {
+		// Another goroutine already set it up, close our instance
+		tPacketRx.Close()
+		return nil
+	}
 
 	// set up multicast addresses
 	// otherwise the kernel might discard the packets
@@ -40,52 +55,95 @@ func (l *LLDP) setUpCapture() error {
 	for _, mac := range multicastAddrs {
 		hwAddr, err := net.ParseMAC(mac)
 		if err != nil {
-			logger.Error().Msgf("unable to parse MAC address %s: %s", mac, err)
+			logger.Error().
+				Str("mac", mac).
+				MACAddr("hwaddr", hwAddr).
+				Err(err).
+				Msg("unable to parse MAC address")
 			continue
 		}
 
 		if err := addMulticastAddr(l.interfaceName, hwAddr); err != nil {
-			logger.Error().Msgf("unable to add multicast address %s: %s", mac, err)
+			logger.Error().
+				MACAddr("hwaddr", hwAddr).
+				Err(err).
+				Msg("unable to add multicast address")
 			continue
 		}
 
 		logger.Info().
 			MACAddr("hwaddr", hwAddr).
-			Msgf("added multicast address")
+			Msg("added multicast address")
 	}
 
-	if err = tPacket.SetBPF(bpfFilter); err != nil {
+	if err = tPacketRx.SetBPF(bpfFilter); err != nil {
-		logger.Error().Msgf("unable to set BPF filter: %s", err)
+		logger.Error().
-		tPacket.Close()
+			Err(err).
+			Msg("unable to set BPF filter")
+		tPacketRx.Close()
 		return err
 	}
 	logger.Info().Msg("BPF filter set")
 
-	l.pktSource = gopacket.NewPacketSource(tPacket, layers.LayerTypeEthernet)
+	l.pktSourceRx = gopacket.NewPacketSource(tPacketRx, layers.LayerTypeEthernet)
-	l.tPacket = tPacket
+	l.tPacketRx = tPacketRx
 
 	return nil
 }
 
+func (l *LLDP) doCapture(logger *zerolog.Logger, rxCtx context.Context) {
+	defer func() {
+		l.mu.Lock()
+		l.rxRunning = false
+		l.mu.Unlock()
+	}()
+
+	packetChan := l.pktSourceRx.Packets()
+	for {
+		select {
+		case packet, ok := <-packetChan:
+			if !ok {
+				logger.Info().Msg("packet source closed")
+				return
+			}
+			if err := l.handlePacket(packet, logger); err != nil {
+				logger.Error().
+					Err(err).
+					Msg("error handling packet")
+			}
+		case <-rxCtx.Done():
+			logger.Info().Msg("LLDP receiver stopped")
+			return
+		}
+	}
+}
+
 func (l *LLDP) startCapture() error {
-	logger := l.l.With().Str("interface", l.interfaceName).Logger()
+	l.mu.Lock()
-	if l.tPacket == nil {
+	defer l.mu.Unlock()
+
+	if l.rxRunning {
+		return nil // Already running
+	}
+
+	if l.tPacketRx == nil {
 		return fmt.Errorf("AFPacket not initialized")
 	}
 
-	if l.pktSource == nil {
+	if l.pktSourceRx == nil {
 		return fmt.Errorf("packet source not initialized")
 	}
 
-	go func() {
+	logger := l.l.With().Str("interface", l.interfaceName).Logger()
 	logger.Info().Msg("starting capture LLDP ethernet frames")
 
-		for packet := range l.pktSource.Packets() {
+	// Create a new context for this instance
-			if err := l.handlePacket(packet, &logger); err != nil {
+	l.rxCtx, l.rxCancel = context.WithCancel(context.Background())
-				logger.Error().Msgf("error handling packet: %s", err)
+	l.rxRunning = true
-			}
+
-		}
+	// Capture context in closure
-	}()
+	rxCtx := l.rxCtx
+	go l.doCapture(&logger, rxCtx)
 
 	return nil
 }
@@ -108,7 +166,8 @@ func (l *LLDP) handlePacket(packet gopacket.Packet, logger *zerolog.Logger) erro
 
 	lldpRaw := packet.Layer(layers.LayerTypeLinkLayerDiscovery)
 	if lldpRaw != nil {
-		logger.Trace().Msgf("Found LLDP Frame")
+		logger.Trace().Msg("Found LLDP Frame")
+		l.l.Info().Hex("packet", packet.Data()).Msg("received packet")
 
 		lldpInfo := packet.Layer(layers.LayerTypeLinkLayerDiscoveryInfo)
 		if lldpInfo == nil {
@@ -124,7 +183,7 @@ func (l *LLDP) handlePacket(packet gopacket.Packet, logger *zerolog.Logger) erro
 
 	cdpRaw := packet.Layer(layers.LayerTypeCiscoDiscovery)
 	if cdpRaw != nil {
-		logger.Trace().Msgf("Found CDP Frame")
+		logger.Trace().Msg("Found CDP Frame")
 
 		cdpInfo := packet.Layer(layers.LayerTypeCiscoDiscoveryInfo)
 		if cdpInfo == nil {
@@ -141,6 +200,32 @@ func (l *LLDP) handlePacket(packet gopacket.Packet, logger *zerolog.Logger) erro
 	return nil
 }
 
+func capabilitiesToString(capabilities layers.LLDPCapabilities) []string {
+	capStr := []string{}
+	if capabilities.Other {
+		capStr = append(capStr, "other")
+	}
+	if capabilities.Repeater {
+		capStr = append(capStr, "repeater")
+	}
+	if capabilities.Bridge {
+		capStr = append(capStr, "bridge")
+	}
+	if capabilities.WLANAP {
+		capStr = append(capStr, "wlanap")
+	}
+	if capabilities.Router {
+		capStr = append(capStr, "router")
+	}
+	if capabilities.Phone {
+		capStr = append(capStr, "phone")
+	}
+	if capabilities.DocSis {
+		capStr = append(capStr, "docsis")
+	}
+	return capStr
+}
+
 func (l *LLDP) handlePacketLLDP(mac string, raw *layers.LinkLayerDiscovery, info *layers.LinkLayerDiscoveryInfo) error {
 	n := &Neighbor{
 		Values: make(map[string]string),
@@ -171,7 +256,15 @@ func (l *LLDP) handlePacketLLDP(mac string, raw *layers.LinkLayerDiscovery, info
 			n.SystemDescription = info.SysDescription
 			n.Values["system_description"] = n.SystemDescription
 		case layers.LLDPTLVMgmtAddress:
-			// n.ManagementAddress = info.MgmtAddress.Address
+			n.ManagementAddress = &ManagementAddress{
+				AddressFamily:    info.MgmtAddress.Subtype.String(),
+				Address:          net.IP(info.MgmtAddress.Address).String(),
+				InterfaceSubtype: info.MgmtAddress.InterfaceSubtype.String(),
+				InterfaceNumber:  info.MgmtAddress.InterfaceNumber,
+				OID:              info.MgmtAddress.OID,
+			}
+		case layers.LLDPTLVSysCapabilities:
+			n.Capabilities = capabilitiesToString(info.SysCapabilities.EnabledCap)
 		case layers.LLDPTLVTTL:
 			n.TTL = uint16(raw.TTL)
 			ttl = time.Duration(n.TTL) * time.Second
@@ -184,9 +277,9 @@ func (l *LLDP) handlePacketLLDP(mac string, raw *layers.LinkLayerDiscovery, info
 	}
 
 	if gotEnd || ttl < 1*time.Second {
-		l.deleteNeighbor(mac)
+		l.deleteNeighbor(n)
 	} else {
-		l.addNeighbor(mac, *n, ttl)
+		l.addNeighbor(n, ttl)
 	}
 
 	return nil
@@ -213,23 +306,61 @@ func (l *LLDP) handlePacketCDP(mac string, raw *layers.CiscoDiscovery, info *lay
 	}
 
 	if len(info.MgmtAddresses) > 0 {
-		n.ManagementAddress = string(info.MgmtAddresses[0])
+		ip := info.MgmtAddresses[0]
+		ipFamily := "ipv4"
+		if ip.To4() == nil {
+			ipFamily = "ipv6"
 		}
 
-	l.addNeighbor(mac, *n, ttl)
+		l.l.Info().
+			Str("ip", ip.String()).
+			Str("ip_family", ipFamily).
+			Interface("ip", ip).
+			Interface("info", info).
+			Msg("parsed IP address")
+
+		n.ManagementAddress = &ManagementAddress{
+			AddressFamily:    ipFamily,
+			Address:          ip.String(),
+			InterfaceSubtype: "if_name",
+			InterfaceNumber:  0,
+			OID:              "",
+		}
+	}
+
+	l.addNeighbor(n, ttl)
 
 	return nil
 }
 
-func (l *LLDP) shutdownCapture() error {
+func (l *LLDP) stopCapture() error {
-	if l.tPacket != nil {
+	l.mu.Lock()
-		l.tPacket.Close()
+	defer l.mu.Unlock()
-		l.tPacket = nil
+
+	if !l.rxRunning {
+		return nil // Already stopped
 	}
 
-	if l.pktSource != nil {
+	logger := l.l.With().Str("interface", l.interfaceName).Logger()
-		l.pktSource = nil
+	logger.Info().Msg("stopping LLDP receiver")
+
+	// Cancel context to signal stop
+	rxCancel := l.rxCancel
+	if rxCancel != nil {
+		rxCancel()
+		l.rxCancel = nil
 	}
 
+	if l.tPacketRx != nil {
+		l.tPacketRx.Close()
+		l.tPacketRx = nil
+	}
+
+	if l.pktSourceRx != nil {
+		l.pktSourceRx = nil
+	}
+
+	time.Sleep(100 * time.Millisecond)
+
 	return nil
 }

internal/lldp/tx.go

@@ -0,0 +1,270 @@
+package lldp
+
+import (
+	"context"
+	"encoding/binary"
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/layers"
+	"github.com/rs/zerolog"
+)
+
+var (
+	lldpDstMac    = net.HardwareAddr([]byte{0x01, 0x80, 0xc2, 0x00, 0x00, 0x0e})
+	lldpEtherType = layers.EthernetTypeLinkLayerDiscovery
+)
+
+// func encodeMandatoryTLV(subType byte, id []byte) []byte {
+// 	// 1 byte: subtype
+// 	// N bytes: ID
+// 	b := make([]byte, 1+len(id))
+// 	b[0] = byte(subtype)
+// 	copy(b[1:], id)
+
+// 	return b
+// }
+
+// func (l *LLDP) createLLDPPayload() ([]byte, error) {
+// 	tlv := &layers.LinkLayerDiscoveryValue{
+// 		Type:  layers.LLDPTLVChassisID,
+
+// }
+
+func tlvStringValue(tlvType layers.LLDPTLVType, value string) layers.LinkLayerDiscoveryValue {
+	return layers.LinkLayerDiscoveryValue{
+		Type:   tlvType,
+		Value:  []byte(value),
+		Length: uint16(len(value)),
+	}
+}
+
+var (
+	capabilityMap = map[string]uint16{
+		"other":        layers.LLDPCapsOther,
+		"repeater":     layers.LLDPCapsRepeater,
+		"bridge":       layers.LLDPCapsBridge,
+		"wlanap":       layers.LLDPCapsWLANAP,
+		"router":       layers.LLDPCapsRouter,
+		"phone":        layers.LLDPCapsPhone,
+		"docsis":       layers.LLDPCapsDocSis,
+		"station_only": layers.LLDPCapsStationOnly,
+		"cvlan":        layers.LLDPCapsCVLAN,
+		"svlan":        layers.LLDPCapsSVLAN,
+		"tmpr":         layers.LLDPCapsTmpr,
+	}
+)
+
+func toLLDPCapabilitiesBytes(capabilities []string) uint16 {
+	r := uint16(0)
+	for _, capability := range capabilities {
+		if _, ok := capabilityMap[capability]; !ok {
+			continue
+		}
+		r |= capabilityMap[capability]
+	}
+	return r
+}
+
+func (l *LLDP) toPayloadValues() []layers.LinkLayerDiscoveryValue {
+	// See also: layers.LinkLayerDiscovery.SerializeTo()
+	r := []layers.LinkLayerDiscoveryValue{}
+
+	l.mu.RLock()
+	opts := l.advertiseOptions
+	l.mu.RUnlock()
+
+	if opts == nil {
+		return r
+	}
+
+	if opts.SysName != "" {
+		r = append(r, tlvStringValue(layers.LLDPTLVSysName, opts.SysName))
+	}
+
+	if opts.SysDescription != "" {
+		r = append(r, tlvStringValue(layers.LLDPTLVSysDescription, opts.SysDescription))
+	}
+
+	if len(opts.SysCapabilities) > 0 {
+		value := make([]byte, 4)
+		binary.BigEndian.PutUint16(value[0:2], toLLDPCapabilitiesBytes(opts.SysCapabilities))
+		binary.BigEndian.PutUint16(value[2:4], toLLDPCapabilitiesBytes(opts.EnabledCapabilities))
+
+		r = append(r, layers.LinkLayerDiscoveryValue{
+			Type:   layers.LLDPTLVSysCapabilities,
+			Value:  value,
+			Length: 4,
+		})
+	}
+
+	// EndTLV will be added by the serializer, we don't need to add it here
+	return r
+}
+
+func (l *LLDP) setUpTx() error {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	// Check if already set up (double-check pattern to prevent duplicate setup)
+	if l.tPacketTx != nil {
+		return nil
+	}
+
+	logger := l.l.With().Str("interface", l.interfaceName).Logger()
+	tPacketTx, err := afPacketNewTPacket(l.interfaceName)
+	if err != nil {
+		return err
+	}
+	logger.Info().Msg("created TPacket instance for sending LLDP packets")
+
+	l.tPacketTx = tPacketTx
+
+	return nil
+}
+
+func (l *LLDP) sendTxPackets() error {
+	l.mu.RLock()
+	defer l.mu.RUnlock()
+
+	logger := l.l.With().Str("interface", l.interfaceName).Logger()
+	iface, err := net.InterfaceByName(l.interfaceName)
+	if err != nil {
+		return err
+	}
+
+	if l.tPacketTx == nil {
+		return fmt.Errorf("AFPacket not initialized")
+	}
+
+	// create payload
+	ethFrame := layers.Ethernet{
+		EthernetType: lldpEtherType,
+		SrcMAC:       iface.HardwareAddr,
+		DstMAC:       lldpDstMac,
+	}
+
+	lldpFrame := layers.LinkLayerDiscovery{
+		ChassisID: layers.LLDPChassisID{
+			Subtype: layers.LLDPChassisIDSubTypeMACAddr,
+			ID:      []byte(iface.HardwareAddr),
+		},
+		PortID: layers.LLDPPortID{
+			Subtype: layers.LLDPPortIDSubtypeIfaceName,
+			ID:      []byte(iface.Name),
+		},
+		TTL:    uint16(3600),
+		Values: l.toPayloadValues(),
+	}
+
+	buf := gopacket.NewSerializeBuffer()
+	if err := gopacket.SerializeLayers(buf, gopacket.SerializeOptions{
+		FixLengths:       true,
+		ComputeChecksums: true,
+	}, &ethFrame, &lldpFrame); err != nil {
+		l.l.Error().Err(err).Msg("unable to serialize packet")
+		return err
+	}
+
+	logger.Trace().Hex("packet", buf.Bytes()).Msg("sending LLDP packet")
+
+	// send packet
+	if err := l.tPacketTx.WritePacketData(buf.Bytes()); err != nil {
+		l.l.Error().Err(err).Msg("unable to send packet")
+		return err
+	}
+
+	return nil
+}
+
+const txInterval = 30 * time.Second // Standard LLDP transmission interval
+
+func (l *LLDP) doSendPeriodically(logger *zerolog.Logger, txCtx context.Context) {
+	l.mu.Lock()
+	l.txRunning = true
+	l.mu.Unlock()
+
+	defer func() {
+		l.mu.Lock()
+		l.txRunning = false
+		l.mu.Unlock()
+	}()
+
+	ticker := time.NewTicker(txInterval)
+	defer ticker.Stop()
+
+	// Send initial packet immediately
+	if err := l.sendTxPackets(); err != nil {
+		logger.Error().Err(err).Msg("error sending initial LLDP packet")
+	}
+
+	for {
+		select {
+		case <-ticker.C:
+			if err := l.sendTxPackets(); err != nil {
+				logger.Error().Err(err).Msg("error sending LLDP packet")
+			}
+		case <-txCtx.Done():
+			logger.Info().Msg("LLDP transmitter stopped")
+			return
+		}
+	}
+}
+
+func (l *LLDP) startTx() error {
+	l.mu.RLock()
+	running := l.txRunning
+	enabled := l.enableTx
+	cancel := l.txCancel
+	l.mu.RUnlock()
+
+	if running || !enabled {
+		return nil
+	}
+
+	if cancel != nil {
+		cancel()
+	}
+
+	l.txCtx, l.txCancel = context.WithCancel(context.Background())
+
+	if err := l.setUpTx(); err != nil {
+		return fmt.Errorf("failed to set up TX: %w", err)
+	}
+
+	logger := l.l.With().Str("interface", l.interfaceName).Logger()
+	logger.Info().Msg("starting LLDP transmitter")
+
+	go l.doSendPeriodically(&logger, l.txCtx)
+
+	return nil
+}
+
+func (l *LLDP) stopTx() error {
+	l.mu.Lock()
+	if !l.txRunning {
+		l.mu.Unlock()
+		return nil // Already stopped
+	}
+
+	logger := l.l.With().Str("interface", l.interfaceName).Logger()
+	logger.Info().Msg("stopping LLDP transmitter")
+
+	// Cancel context to signal stop
+	txCancel := l.txCancel
+	l.txRunning = false
+	l.mu.Unlock()
+
+	// Cancel context (goroutine will handle cleanup)
+	if txCancel != nil {
+		txCancel()
+	}
+
+	// Wait a bit for goroutine to finish
+	// Note: In a production system, you might want to use sync.WaitGroup
+	// for proper synchronization, but for now this is acceptable
+	time.Sleep(100 * time.Millisecond)
+
+	return nil
+}

network.go

@@ -163,13 +163,22 @@ func initNetwork() error {
 
 	networkManager = nm
 
-	lldpService = lldp.NewLLDP(&lldp.LLDPOptions{
+	advertiseOptions := &lldp.AdvertiseOptions{
+		SysName:             networkManager.Hostname(),
+		SysDescription:      toLLDPSysDescription(nc),
+		SysCapabilities:     []string{"other", "router", "wlanap"},
+		EnabledCapabilities: []string{"other"},
+	}
+
+	lldpService = lldp.NewLLDP(&lldp.Options{
 		InterfaceName:    NetIfName,
 		EnableRx:         nc.LLDPMode.String != "disabled",
 		EnableTx:         nc.LLDPMode.String != "disabled",
+		AdvertiseOptions: advertiseOptions,
 		OnChange: func(neighbors []lldp.Neighbor) {
 			writeJSONRPCEvent("lldpNeighbors", neighbors, currentSession)
 		},
+		Logger: networkLogger,
 	})
 	if err := lldpService.Start(); err != nil {
 		networkLogger.Error().Err(err).Msg("failed to start LLDP service")
@@ -178,6 +187,15 @@ func initNetwork() error {
 	return nil
 }
 
+func toLLDPSysDescription(nc *types.NetworkConfig) string {
+	systemVersion, appVersion, err := GetLocalVersion()
+	if err == nil {
+		return fmt.Sprintf("JetKVM (app: %s)", GetBuiltAppVersion())
+	}
+
+	return fmt.Sprintf("JetKVM (app: %s, system: %s)", appVersion.String(), systemVersion.String())
+}
+
 func setHostname(nm *nmlite.NetworkManager, hostname, domain string) error {
 	if nm == nil {
 		return nil

ui/src/components/LLDPNeighborsCard.tsx

@@ -21,7 +21,7 @@ const LLDPDataLine = ({ label, value, className }: LLDPDataLineProps) => {
   );
 }
 
-export default function LLDPNeighCard({
+export default function LLDPNeighborsCard({
   neighbors,
 }: {
   neighbors: LLDPNeighbor[];
@@ -49,7 +49,7 @@ export default function LLDPNeighCard({
                     )}
 
                     {neighbor.system_description && (
-                      <LLDPDataLine label="System Description" value={neighbor.system_description} />
+                      <LLDPDataLine label="System Description" value={neighbor.system_description} className="col-span-2" />
                     )}
 
                     {neighbor.chassis_id && (
@@ -65,7 +65,7 @@ export default function LLDPNeighCard({
                     )}
 
                     {neighbor.management_address && (
-                      <LLDPDataLine label="Management Address" value={neighbor.management_address} />
+                      <LLDPDataLine label="Management Address" value={neighbor.management_address.address} />
                     )}
 
                     {neighbor.mac && (

ui/src/hooks/stores.ts

@@ -783,6 +783,14 @@ export interface IPv6StaticConfig {
   dns: string[];
 }
 
+export interface LLDPManagementAddress {
+  address_family: string;
+  address: string;
+  interface_subtype: string;
+  interface_number: number;
+  oid: string;
+}
+
 export interface LLDPNeighbor {
   mac: string;
   source: string;
@@ -791,8 +799,9 @@ export interface LLDPNeighbor {
   port_description: string;
   system_name: string;
   system_description: string;
+  capabilities: string[];
   ttl: number | null;
-  management_address: string | null;
+  management_address: LLDPManagementAddress | null;
   values: Record<string, string>;
 }
 

ui/src/routes/devices.$id.settings.network.tsx

@@ -23,14 +23,14 @@ import StaticIpv4Card from "@components/StaticIpv4Card";
 import StaticIpv6Card from "@components/StaticIpv6Card";
 import { useCopyToClipboard } from "@components/useCopyToClipBoard";
 import { netMaskFromCidr4 } from "@/utils/ip";
-import { callJsonRpc, getNetworkSettings, getNetworkState } from "@/utils/jsonrpc";
+import { getNetworkSettings, getNetworkState, getLLDPNeighbors } from "@/utils/jsonrpc";
 import notifications from "@/notifications";
 import { m } from "@localizations/messages";
-import LLDPNeighCard from "@components/LLDPNeigh";
+import LLDPNeighborsCard from "@components/LLDPNeighborsCard";
 
 dayjs.extend(relativeTime);
 
-const isLLDPAvailable = false; // LLDP is not supported yet
+const isLLDPAvailable = true; // LLDP is now supported
 
 const resolveOnRtcReady = () => {
   return new Promise(resolve => {
@@ -100,14 +100,10 @@ export default function SettingsNetworkRoute() {
 
   const [lldpNeighbors, setLldpNeighbors] = useState<LLDPNeighbor[]>([]);
   const fetchLLDPNeighbors = useCallback(async () => {
-    send("getLLDPNeighbors", {}, (resp) => {
+    const neighbors = await getLLDPNeighbors();
-      if ("error" in resp) {
+    setLldpNeighbors(neighbors);
-        // notifications.error(m.network_lldp_neighbors_fetch_failed({ error: neighbors.error.message || m.unknown_error() }));
+  }, [setLldpNeighbors]);
-      } else {
+
-        setLldpNeighbors(resp.result as LLDPNeighbor[]);
-      }
-    });
-  }, [setLldpNeighbors, send]);
   useEffect(() => {
     fetchLLDPNeighbors();
   }, [fetchLLDPNeighbors]);
@@ -475,11 +471,6 @@ export default function SettingsNetworkRoute() {
                 />
               </SettingsItem>
 
-              <div>
-                <AutoHeight>
-                  <LLDPNeighCard neighbors={lldpNeighbors} />
-                </AutoHeight>
-              </div>
 
               <div>
                 <AutoHeight>
@@ -561,9 +552,10 @@ export default function SettingsNetworkRoute() {
                 </AutoHeight>
               </div>
 
-              { isLLDPAvailable &&
+              {isLLDPAvailable &&
                 (
-                    <div className="hidden space-y-4">
+                  <div className="space-y-4">
+                    <div className="space-y-4">
                       <SettingsItem
                         title={m.network_ll_dp_title()}
                         description={m.network_ll_dp_description()}
@@ -579,6 +571,10 @@ export default function SettingsNetworkRoute() {
                         />
                       </SettingsItem>
                     </div>
+                    <AutoHeight>
+                      <LLDPNeighborsCard neighbors={lldpNeighbors} />
+                    </AutoHeight>
+                  </div>
                 )
               }
 

ui/src/utils/jsonrpc.ts

@@ -1,4 +1,4 @@
-import { useRTCStore } from "@/hooks/stores";
+import { LLDPNeighbor, useRTCStore } from "@/hooks/stores";
 import { sleep } from "@/utils";
 
 // JSON-RPC utility for use outside of React components
@@ -170,6 +170,14 @@ export async function getNetworkState() {
   return response.result;
 }
 
+export async function getLLDPNeighbors() {
+  const response = await callJsonRpc<LLDPNeighbor[]>({ method: "getLLDPNeighbors" });
+  if (response.error) {
+    throw new Error(response.error.message);
+  }
+  return response.result;
+}
+
 export async function renewDHCPLease() {
   const response = await callJsonRpc({ method: "renewDHCPLease" });
   if (response.error) {