diff --git a/capture/capture.go b/capture/capture.go
new file mode 100644
index 0000000..edb1c91
--- /dev/null
+++ b/capture/capture.go
@@ -0,0 +1,90 @@
+package capture
+
+import (
+	"fmt"
+
+	"git.freifunk-franken.de/jkimmel/abbel/packet"
+	"github.com/google/gopacket"
+	"github.com/google/gopacket/afpacket"
+	"github.com/google/gopacket/layers"
+	"golang.org/x/net/bpf"
+	"inet.af/netaddr"
+)
+
+var (
+	// tcpdump -y RAW -dd ip6 and udp dst port 6696
+	babelBPFRAW = []bpf.RawInstruction{
+		{0x30, 0, 0, 0x00000000},
+		{0x54, 0, 0, 0x000000f0},
+		{0x15, 0, 5, 0x00000060},
+		{0x30, 0, 0, 0x00000006},
+		{0x15, 0, 3, 0x00000011},
+		{0x28, 0, 0, 0x0000002a},
+		{0x15, 0, 1, 0x00001a28},
+		{0x6, 0, 0, 0x00040000},
+		{0x6, 0, 0, 0x00000000},
+	}
+)
+
+type Handle struct {
+	tp *afpacket.TPacket
+}
+
+func FromInterface(iface string) (Handle, error) {
+	var h Handle
+	var err error
+
+	if iface != "any" {
+		h.tp, err = afpacket.NewTPacket(
+			afpacket.SocketDgram,
+			afpacket.OptInterface(iface),
+		)
+	} else {
+		h.tp, err = afpacket.NewTPacket(
+			afpacket.SocketDgram,
+		)
+	}
+
+	if err != nil {
+		fmt.Println("here")
+		return Handle{}, err
+	}
+
+	err = h.tp.SetBPF(babelBPFRAW)
+	if err != nil {
+		return Handle{}, err
+	}
+
+	return h, nil
+}
+
+func (h Handle) Close() error {
+	h.tp.Close()
+	return nil
+}
+
+func (h Handle) ReadFrom(b []byte) (body []byte, src netaddr.IP, ifindex int, err error) {
+	data, ci, err := h.tp.ZeroCopyReadPacketData()
+	if err != nil {
+		return nil, netaddr.IP{}, 0, err
+	}
+	pckt := gopacket.NewPacket(data, layers.LayerTypeIPv6, gopacket.NoCopy)
+	ip6, ok := pckt.NetworkLayer().(*layers.IPv6)
+	if !ok {
+		return nil, netaddr.IP{}, 0, fmt.Errorf("Expected IPv6 layer, got %v", pckt.NetworkLayer())
+	}
+
+	src, ok = netaddr.FromStdIP(ip6.SrcIP)
+	if !ok {
+		return nil, netaddr.IP{}, 0, fmt.Errorf("Error parsing packet src address %q", ip6.SrcIP)
+	}
+
+	payload := pckt.ApplicationLayer().Payload()
+	copy(b, payload)
+	b, err = packet.Validate(b[:len(payload)])
+	if err != nil {
+		return nil, netaddr.IP{}, 0, err
+	}
+
+	return b, src, ci.InterfaceIndex, nil
+}
diff --git a/go.mod b/go.mod
index 93b0213..b6fc09c 100644
--- a/go.mod
+++ b/go.mod
@@ -3,6 +3,7 @@ module git.freifunk-franken.de/jkimmel/abbel
 go 1.0
 
 require (
+	github.com/google/gopacket v1.1.19
 	golang.org/x/net v0.0.0-20210226172049-e18ecbb05110
 	inet.af/netaddr v0.0.0-20211027220019-c74959edd3b6
 )
diff --git a/go.sum b/go.sum
index 1bec611..b2e49b4 100644
--- a/go.sum
+++ b/go.sum
@@ -1,4 +1,6 @@
 github.com/dvyukov/go-fuzz v0.0.0-20210103155950-6a8e9d1f2415/go.mod h1:11Gm+ccJnvAhCNLlf5+cS9KjtbaD5I5zaZpFMsTHWTw=
+github.com/google/gopacket v1.1.19 h1:ves8RnFZPGiFnTS0uPQStjwru6uO6h+nlr9j6fL7kF8=
+github.com/google/gopacket v1.1.19/go.mod h1:iJ8V8n6KS+z2U1A8pUwu8bW5SyEMkXJB8Yo/Vo+TKTo=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 go4.org/intern v0.0.0-20211027215823-ae77deb06f29 h1:UXLjNohABv4S58tHmeuIZDO6e3mHpW2Dx33gaNt03LE=
 go4.org/intern v0.0.0-20211027215823-ae77deb06f29/go.mod h1:cS2ma+47FKrLPdXFpr7CuxiTW3eyJbWew4qx0qtQWDA=
@@ -7,6 +9,8 @@ go4.org/unsafe/assume-no-moving-gc v0.0.0-20211027215541-db492cf91b37/go.mod h1:
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+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/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
@@ -26,6 +30,7 @@ golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20200130002326-2f3ba24bd6e7/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
 golang.org/x/tools v0.1.0/go.mod h1:xkSsbof2nBLbhDlRMhhhyNLN/zl3eTqcnHD5viDpcZ0=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
diff --git a/main.go b/main.go
index 9eae32d..f042cb1 100644
--- a/main.go
+++ b/main.go
@@ -4,14 +4,17 @@ import (
 	"fmt"
 	"log"
 
+	"git.freifunk-franken.de/jkimmel/abbel/capture"
 	"git.freifunk-franken.de/jkimmel/abbel/packet"
 	"git.freifunk-franken.de/jkimmel/abbel/tlv"
+	"inet.af/netaddr"
 )
 
 type options struct {
-	Group string
-	Port  uint16
-	Ifs   []string
+	Group      string
+	Port       uint16
+	Ifs        []string
+	UseCapture bool
 }
 
 func parseOpts() (options, error) {
@@ -19,16 +22,39 @@ func parseOpts() (options, error) {
 	var err error
 
 	opt = options{
-		Group: "ff02:0:0:0:0:0:1:6",
-		Port:  6696,
-		Ifs:   []string{"babel"},
+		Group:      "ff02:0:0:0:0:0:1:6",
+		Port:       6696,
+		Ifs:        []string{"babel"},
+		UseCapture: false,
 	}
 
 	return opt, err
 }
 
+type updatesKey struct {
+	prefix   netaddr.IPPrefix
+	routerID tlv.RouterID
+	nexthop  netaddr.IP
+}
+
+var (
+	updates = map[updatesKey]tlv.Update{}
+)
+
+type BabelPacketConn interface {
+	ReadFrom(b []byte) (body []byte, src netaddr.IP, ifindex int, err error)
+	Close() error
+}
+
 func run(opt options) error {
-	conn, err := packet.Listen(opt.Group, opt.Port, opt.Ifs...)
+	var err error
+	var conn BabelPacketConn
+
+	if opt.UseCapture {
+		conn, err = capture.FromInterface(opt.Ifs[0])
+	} else {
+		conn, err = packet.Listen(opt.Group, opt.Port, opt.Ifs...)
+	}
 	if err != nil {
 		return err
 	}
@@ -37,36 +63,39 @@ func run(opt options) error {
 	buf := [4096]byte{}
 	var s tlv.PacketDecoder
 	for {
-		b, src, rcm, err := conn.ReadFrom(buf[:])
+		b, src, ifindex, err := conn.ReadFrom(buf[:])
 		if err != nil {
 			fmt.Println("Skipping packet:", err)
 			continue
 		}
 
 		fmt.Print("\x1B[1m")
-		fmt.Printf("Packet size %4d %s", len(b), rcm)
+		fmt.Printf("Packet size %4d from %s", len(b), src)
 		fmt.Println("\x1B[0m")
 
-		s.Reset(b, src, rcm.IfIndex)
+		s.Reset(b, src, ifindex)
 		for s.Scan() {
 			switch t := s.TLV().(type) {
 			case tlv.NextHop:
-				fmt.Printf("%12s %s\n", t.T(), t.Address)
+				//fmt.Printf("%12s %s\n", t.T(), t.Address)
 			case tlv.Hello:
 				fmt.Printf("% 12s %+v\n", t.T(), t)
 			case tlv.Update:
-				if err != nil {
-					fmt.Println(t, t.Prefix, err)
-				} else {
-					if t.Metric == 0xFFFF {
-						fmt.Print("\x1B[31m")
-					} else {
-						fmt.Print("\x1B[36m")
-					}
-					fmt.Printf("% 12s %-43s%s\x1B[0m\n", t.T(), t.Prefix, t.FormatHeader())
+				key := updatesKey{t.Prefix, t.RouterID, t.NextHop}
+				tmetric := t.Metric
+				diff := int(tmetric) - int(updates[key].Metric)
+				updates[key] = t
+				if diff == 0 && tmetric != 0xFFFF {
+					break
 				}
+				if t.Metric == 0xFFFF {
+					fmt.Print("\x1B[31m")
+				} else {
+					fmt.Print("\x1B[36m")
+				}
+				fmt.Printf("% 12s %-43s%+d %s\x1B[0m\n", t.T(), t.Prefix, diff, t.FormatHeader())
 			case tlv.RouterID:
-				fmt.Printf("%12s %s\n", t.T(), t)
+				//fmt.Printf("%12s %s\n", t.T(), t)
 			case tlv.RouteRequest:
 				fmt.Printf("%12s %s\n", t.T(), t.Prefix)
 			case tlv.Raw:
diff --git a/packet/packet.go b/packet/packet.go
index 23cc225..83d04ae 100644
--- a/packet/packet.go
+++ b/packet/packet.go
@@ -63,16 +63,11 @@ func (c Conn) JoinGroup(ifname string, addr string) error {
 	return c.v6pc.JoinGroup(ifi, &net.UDPAddr{IP: ip.IPAddr().IP})
 }
 
-func (c Conn) ReadFrom(b []byte) (body []byte, src netaddr.IP, rcm *ipv6.ControlMessage, err error) {
-	var n int
-	n, rcm, _, err = c.v6pc.ReadFrom(b)
-	if err != nil {
-		return nil, netaddr.IP{}, nil, err
-	}
+func Validate(b []byte) ([]byte, error) {
+	n := len(b)
 
-	b = b[:n]
-	if len(b) < BabelPacketHeaderSize {
-		return nil, netaddr.IP{}, nil, fmt.Errorf("Packet too short: %d", len(b))
+	if n < BabelPacketHeaderSize {
+		return nil, fmt.Errorf("Packet too short: %d", len(b))
 	}
 
 	magic := b[0]
@@ -81,22 +76,36 @@ func (c Conn) ReadFrom(b []byte) (body []byte, src netaddr.IP, rcm *ipv6.Control
 	b = b[4:]
 
 	if magic != BabelMagic {
-		return nil, netaddr.IP{}, nil, fmt.Errorf("Invalid magic number %d", magic)
+		return nil, fmt.Errorf("Invalid magic number %d", magic)
 	}
 	if version != BabelVersion {
-		return nil, netaddr.IP{}, nil, fmt.Errorf("Unsupported version number %d", version)
+		return nil, fmt.Errorf("Unsupported version number %d", version)
 	}
 	if int(length) > len(b) {
-		return nil, netaddr.IP{}, nil, fmt.Errorf("Invalid length for packet of size %d: %d", n, length)
+		return nil, fmt.Errorf("Invalid length for packet of size %d: %d", n, length)
+	}
+
+	return b, nil
+}
+
+func (c Conn) ReadFrom(b []byte) (body []byte, src netaddr.IP, ifindex int, err error) {
+	n, rcm, _, err := c.v6pc.ReadFrom(b)
+	if err != nil {
+		return nil, netaddr.IP{}, 0, err
+	}
+
+	b, err = Validate(b[:n])
+	if err != nil {
+		return nil, netaddr.IP{}, 0, err
 	}
 
 	var ok bool
 	src, ok = netaddr.FromStdIPRaw(rcm.Src)
 
 	if !ok {
-		return nil, netaddr.IP{}, nil, fmt.Errorf("Invalid src address %q", rcm.Src)
+		return nil, netaddr.IP{}, 0, fmt.Errorf("Invalid src address %q", rcm.Src)
 	}
 
-	return b, src, rcm, err
+	return b, src, rcm.IfIndex, err
 
 }