Merge pull request #49 from wader/bsd-lo-and-link-group

pcap,pcapng,bsd_loopback_frame: Add decoder, refactor link frame into…

README.md

@@ -94,7 +94,7 @@ cp fq /usr/local/bin
 
 [./formats_list.jq]: sh-start
 
-aac_frame, adts, adts_frame, apev2, av1_ccr, av1_frame, av1_obu, avc_annexb, avc_au, avc_dcr, avc_nalu, avc_pps, avc_sei, avc_sps, bzip2, dns, dns_tcp, elf, ether8023_frame, exif, flac, flac_frame, flac_metadatablock, flac_metadatablocks, flac_picture, flac_streaminfo, gif, gzip, hevc_annexb, hevc_au, hevc_dcr, hevc_nalu, icc_profile, icmp, id3v1, id3v11, id3v2, ipv4_packet, jpeg, json, matroska, mp3, mp3_frame, mp4, mpeg_asc, mpeg_es, mpeg_pes, mpeg_pes_packet, mpeg_spu, mpeg_ts, ogg, ogg_page, opus_packet, pcap, pcapng, png, protobuf, protobuf_widevine, pssh_playready, raw, sll2_packet, sll_packet, tar, tcp_segment, tiff, udp_datagram, vorbis_comment, vorbis_packet, vp8_frame, vp9_cfm, vp9_frame, vpx_ccr, wav, webp, xing, zip
+aac_frame, adts, adts_frame, apev2, av1_ccr, av1_frame, av1_obu, avc_annexb, avc_au, avc_dcr, avc_nalu, avc_pps, avc_sei, avc_sps, bsd_loopback_frame, bzip2, dns, dns_tcp, elf, ether8023_frame, exif, flac, flac_frame, flac_metadatablock, flac_metadatablocks, flac_picture, flac_streaminfo, gif, gzip, hevc_annexb, hevc_au, hevc_dcr, hevc_nalu, icc_profile, icmp, id3v1, id3v11, id3v2, ipv4_packet, jpeg, json, matroska, mp3, mp3_frame, mp4, mpeg_asc, mpeg_es, mpeg_pes, mpeg_pes_packet, mpeg_spu, mpeg_ts, ogg, ogg_page, opus_packet, pcap, pcapng, png, protobuf, protobuf_widevine, pssh_playready, raw, sll2_packet, sll_packet, tar, tcp_segment, tiff, udp_datagram, vorbis_comment, vorbis_packet, vp8_frame, vp9_cfm, vp9_frame, vpx_ccr, wav, webp, xing, zip
 
 [#]: sh-end
 

doc/formats.md

@@ -18,6 +18,7 @@
 |`avc_pps`             |H.264/AVC&nbsp;Picture&nbsp;Parameter&nbsp;Set                |<sub></sub>|
 |`avc_sei`             |H.264/AVC&nbsp;Supplemental&nbsp;Enhancement&nbsp;Information |<sub></sub>|
 |`avc_sps`             |H.264/AVC&nbsp;Sequence&nbsp;Parameter&nbsp;Set               |<sub></sub>|
+|`bsd_loopback_frame`  |BSD&nbsp;loopback&nbsp;frame                                  |<sub>`ipv4_packet`</sub>|
 |`bzip2`               |bzip2&nbsp;compression                                        |<sub>`probe`</sub>|
 |`dns`                 |DNS&nbsp;packet                                               |<sub></sub>|
 |`dns_tcp`             |DNS&nbsp;packet&nbsp;(TCP)                                    |<sub></sub>|
@@ -57,8 +58,8 @@
 |`ogg`                 |OGG&nbsp;file                                                 |<sub>`ogg_page` `vorbis_packet` `opus_packet` `flac_metadatablock` `flac_frame`</sub>|
 |`ogg_page`            |OGG&nbsp;page                                                 |<sub></sub>|
 |`opus_packet`         |Opus&nbsp;packet                                              |<sub>`vorbis_comment`</sub>|
-|`pcap`                |PCAP&nbsp;packet&nbsp;capture                                 |<sub>`ether8023_frame` `sll_packet` `sll2_packet` `tcp_stream` `ipv4_packet`</sub>|
+|`pcap`                |PCAP&nbsp;packet&nbsp;capture                                 |<sub>`link_frame` `tcp_stream` `ipv4_packet`</sub>|
-|`pcapng`              |PCAPNG&nbsp;packet&nbsp;capture                               |<sub>`ether8023_frame` `sll_packet` `sll2_packet` `tcp_stream` `ipv4_packet`</sub>|
+|`pcapng`              |PCAPNG&nbsp;packet&nbsp;capture                               |<sub>`link_frame` `tcp_stream` `ipv4_packet`</sub>|
 |`png`                 |Portable&nbsp;Network&nbsp;Graphics&nbsp;file                 |<sub>`icc_profile` `exif`</sub>|
 |`protobuf`            |Protobuf                                                      |<sub></sub>|
 |`protobuf_widevine`   |Widevine&nbsp;protobuf                                        |<sub>`protobuf`</sub>|
@@ -81,6 +82,7 @@
 |`xing`                |Xing&nbsp;header                                              |<sub></sub>|
 |`zip`                 |ZIP&nbsp;archive                                              |<sub>`probe`</sub>|
 |`image`               |Group                                                         |<sub>`gif` `jpeg` `mp4` `png` `tiff` `webp`</sub>|
+|`link_frame`          |Group                                                         |<sub>`bsd_loopback_frame` `ether8023_frame` `sll2_packet` `sll_packet`</sub>|
 |`probe`               |Group                                                         |<sub>`adts` `bzip2` `elf` `flac` `gif` `gzip` `jpeg` `json` `matroska` `mp3` `mp4` `mpeg_ts` `ogg` `pcap` `pcapng` `png` `tar` `tiff` `wav` `webp` `zip`</sub>|
 |`tcp_stream`          |Group                                                         |<sub>`dns`</sub>|
 |`udp_payload`         |Group                                                         |<sub>`dns`</sub>|

format/dns/dns.go

@@ -271,9 +271,9 @@ func dnsUDPDecode(d *decode.D, in interface{}) interface{} {
 		}
 		d.Fatalf("wrong port")
 	}
-	if udi, ok := in.(format.UDPDatagramIn); ok {
+	if upi, ok := in.(format.UDPPayloadIn); ok {
-		if udi.DestinationPort == format.UDPPortDomain || udi.SourcePort == format.UDPPortDomain ||
+		if upi.DestinationPort == format.UDPPortDomain || upi.SourcePort == format.UDPPortDomain ||
-			udi.DestinationPort == format.UDPPortMDNS || udi.SourcePort == format.UDPPortMDNS {
+			upi.DestinationPort == format.UDPPortMDNS || upi.SourcePort == format.UDPPortMDNS {
 			return dnsDecode(d, false)
 		}
 		d.Fatalf("wrong port")

format/format.go

@@ -8,6 +8,7 @@ const (
 	IMAGE       = "image"
 	TCP_STREAM  = "tcp_stream"
 	UDP_PAYLOAD = "udp_payload"
+	LINK_FRAME  = "link_frame"
 
 	RAW  = "raw"
 	JSON = "json"
@@ -15,6 +16,7 @@ const (
 	DNS                = "dns"
 	DNS_TCP            = "dns_tcp"
 	ETHER8023_FRAME    = "ether8023_frame"
+	BSD_LOOPBACK_FRAME = "bsd_loopback_frame"
 	SLL_PACKET         = "sll_packet"
 	SLL2_PACKET        = "sll2_packet"
 	IPV4_PACKET        = "ipv4_packet"
@@ -187,7 +189,17 @@ type MP3FrameOut struct {
 	ChannelModeIndex int
 }
 
-type UDPDatagramIn struct {
+type In struct {
+	SourcePort      int
+	DestinationPort int
+}
+
+type LinkFrameIn struct {
+	Type         int
+	LittleEndian bool // pcap endian etc
+}
+
+type UDPPayloadIn struct {
 	SourcePort      int
 	DestinationPort int
 }

format/inet/bsd_loopback_frame.go

@@ -0,0 +1,58 @@
+package inet
+
+// TODO: rename NetworkLayer? wireshark calls it "Family", pcap-linktype(7) calls it "network-layer protocol"
+
+import (
+	"github.com/wader/fq/format"
+	"github.com/wader/fq/format/registry"
+	"github.com/wader/fq/pkg/decode"
+	"github.com/wader/fq/pkg/scalar"
+)
+
+var bsdLoopbackFrameIPv4Format decode.Group
+
+func init() {
+	registry.MustRegister(decode.Format{
+		Name:        format.BSD_LOOPBACK_FRAME,
+		Description: "BSD loopback frame",
+		Groups:      []string{format.LINK_FRAME},
+		Dependencies: []decode.Dependency{
+			{Names: []string{format.IPV4_PACKET}, Group: &bsdLoopbackFrameIPv4Format},
+		},
+		DecodeFn: decodeLoopbackFrame,
+	})
+}
+
+const (
+	bsdLoopbackNetworkLayerIPv4 = 2
+)
+
+var bsdLoopbackFrameNetworkLayerFormat = map[uint64]*decode.Group{
+	bsdLoopbackNetworkLayerIPv4: &bsdLoopbackFrameIPv4Format,
+}
+
+var bsdLookbackNetworkLayerMap = scalar.UToScalar{
+	bsdLoopbackNetworkLayerIPv4: {Sym: "ipv4", Description: `Internet protocol v4`},
+}
+
+func decodeLoopbackFrame(d *decode.D, in interface{}) interface{} {
+	lsi, ok := in.(format.LinkFrameIn)
+	if ok {
+		if lsi.Type != format.LinkTypeNULL {
+			d.Fatalf("wrong link type")
+		}
+		if lsi.LittleEndian {
+			d.Endian = decode.LittleEndian
+		}
+	}
+	// if no LinkFrameIn assume big endian for now
+
+	networkLayer := d.FieldU32("network_layer", bsdLookbackNetworkLayerMap, scalar.Hex)
+	if g, ok := bsdLoopbackFrameNetworkLayerFormat[networkLayer]; ok {
+		d.FieldFormatLen("packet", d.BitsLeft(), *g, nil)
+	} else {
+		d.FieldRawLen("data", d.BitsLeft())
+	}
+
+	return nil
+}

format/inet/ether8023_frame.go

@@ -18,10 +18,11 @@ func init() {
 	registry.MustRegister(decode.Format{
 		Name:        format.ETHER8023_FRAME,
 		Description: "Ethernet 802.3 frame",
+		Groups:      []string{format.LINK_FRAME},
 		Dependencies: []decode.Dependency{
 			{Names: []string{format.IPV4_PACKET}, Group: &ether8023FrameIPv4Format},
 		},
-		DecodeFn: decodeEthernet,
+		DecodeFn: decodeEthernetFrame,
 	})
 }
 
@@ -37,7 +38,13 @@ var mapUToEtherSym = scalar.Fn(func(s scalar.S) (scalar.S, error) {
 	return s, nil
 })
 
-func decodeEthernet(d *decode.D, in interface{}) interface{} {
+func decodeEthernetFrame(d *decode.D, in interface{}) interface{} {
+	if lsi, ok := in.(format.LinkFrameIn); ok {
+		if lsi.Type != format.LinkTypeETHERNET {
+			d.Fatalf("wrong link type")
+		}
+	}
+
 	d.FieldU("destination", 48, mapUToEtherSym, scalar.Hex)
 	d.FieldU("source", 48, mapUToEtherSym, scalar.Hex)
 	etherType := d.FieldU16("ether_type", format.EtherTypeMap, scalar.Hex)

format/inet/flowsdecoder/flowsdecoder.go

@@ -141,6 +141,10 @@ func (fd *Decoder) EthernetFrame(bs []byte) error {
 	return fd.packet(gopacket.NewPacket(bs, layers.LayerTypeEthernet, gopacket.Lazy))
 }
 
+func (fd *Decoder) LoopbackFrame(bs []byte) error {
+	return fd.packet(gopacket.NewPacket(bs, layers.LayerTypeLoopback, gopacket.Lazy))
+}
+
 func (fd *Decoder) packet(p gopacket.Packet) error {
 	// TODO: linkType
 	ip4Layer := p.Layer(layers.LayerTypeIPv4)

format/inet/sll2_packet.go

@@ -16,6 +16,7 @@ func init() {
 	registry.MustRegister(decode.Format{
 		Name:        format.SLL2_PACKET,
 		Description: "Linux cooked capture encapsulation v2",
+		Groups:      []string{format.LINK_FRAME},
 		Dependencies: []decode.Dependency{
 			{Names: []string{format.ETHER8023_FRAME}, Group: &sllPacket2Ether8023Format},
 		},
@@ -28,6 +29,12 @@ var sllPacket2FrameTypeFormat = map[uint64]*decode.Group{
 }
 
 func decodeSLL2(d *decode.D, in interface{}) interface{} {
+	if lsi, ok := in.(format.LinkFrameIn); ok {
+		if lsi.Type != format.LinkTypeLINUX_SLL2 {
+			d.Fatalf("wrong link type")
+		}
+	}
+
 	protcolType := d.FieldU16("protocol_type", format.EtherTypeMap, scalar.Hex)
 	d.FieldU16("reserved")
 	d.FieldU32("interface_index")

format/inet/sll_packet.go

@@ -16,6 +16,7 @@ func init() {
 	registry.MustRegister(decode.Format{
 		Name:        format.SLL_PACKET,
 		Description: "Linux cooked capture encapsulation",
+		Groups:      []string{format.LINK_FRAME},
 		Dependencies: []decode.Dependency{
 			{Names: []string{format.ETHER8023_FRAME}, Group: &sllPacketEther8023Format},
 		},
@@ -112,6 +113,12 @@ var arpHdrTypeMAp = scalar.UToScalar{
 }
 
 func decodeSLL(d *decode.D, in interface{}) interface{} {
+	if lsi, ok := in.(format.LinkFrameIn); ok {
+		if lsi.Type != format.LinkTypeLINUX_SLL {
+			d.Fatalf("wrong link type")
+		}
+	}
+
 	d.FieldU16("packet_type", sllPacketTypeMap)
 	arpHdrType := d.FieldU16("arphdr_type", arpHdrTypeMAp)
 	addressLength := d.FieldU16("link_address_length")

format/inet/udp_datagram.go

@@ -27,7 +27,7 @@ func decodeUDP(d *decode.D, in interface{}) interface{} {
 	d.FieldU16("checksum", scalar.Hex)
 
 	dataLen := int64(length-8) * 8
-	if dv, _, _ := d.TryFieldFormatLen("data", dataLen, udpPayloadFormat, format.UDPDatagramIn{
+	if dv, _, _ := d.TryFieldFormatLen("data", dataLen, udpPayloadFormat, format.UDPPayloadIn{
 		SourcePort:      int(soucePort),
 		DestinationPort: int(destPort),
 	}); dv == nil {

format/pcap/pcap.go

@@ -11,9 +11,7 @@ import (
 	"github.com/wader/fq/pkg/scalar"
 )
 
-var pcapEther8023Format decode.Group
+var pcapLinkFrameFormat decode.Group
-var pcapSLLPacket decode.Group
-var pcapSLL2Packet decode.Group
 var pcapTCPStreamFormat decode.Group
 var pcapIPv4PacketFormat decode.Group
 
@@ -33,9 +31,7 @@ func init() {
 		Description: "PCAP packet capture",
 		Groups:      []string{format.PROBE},
 		Dependencies: []decode.Dependency{
-			{Names: []string{format.ETHER8023_FRAME}, Group: &pcapEther8023Format},
+			{Names: []string{format.LINK_FRAME}, Group: &pcapLinkFrameFormat},
-			{Names: []string{format.SLL_PACKET}, Group: &pcapSLLPacket},
-			{Names: []string{format.SLL2_PACKET}, Group: &pcapSLL2Packet},
 			{Names: []string{format.TCP_STREAM}, Group: &pcapTCPStreamFormat},
 			{Names: []string{format.IPV4_PACKET}, Group: &pcapIPv4PacketFormat},
 		},
@@ -89,9 +85,10 @@ func decodePcap(d *decode.D, in interface{}) interface{} {
 					_ = fn(fd, bs)
 				}
 
-				if g, ok := linkToFormat[linkType]; ok {
+				if dv, _, _ := d.TryFieldFormatLen("packet", int64(inclLen)*8, pcapLinkFrameFormat, format.LinkFrameIn{
-					d.FieldFormatLen("packet", int64(inclLen)*8, *g, nil)
+					Type:         linkType,
-				} else {
+					LittleEndian: d.Endian == decode.LittleEndian,
+				}); dv == nil {
 					d.FieldRawLen("packet", int64(inclLen)*8)
 				}
 			})

format/pcap/pcapng.go

@@ -13,9 +13,7 @@ import (
 	"github.com/wader/fq/pkg/scalar"
 )
 
-var pcapngEther8023Format decode.Group
+var pcapngLinkFrameFormat decode.Group
-var pcapngSLLPacketFormat decode.Group
-var pcapngSLL2PacketFormat decode.Group
 var pcapngTCPStreamFormat decode.Group
 var pcapngIPvPacket4Format decode.Group
 
@@ -26,9 +24,7 @@ func init() {
 		RootArray:   true,
 		Groups:      []string{format.PROBE},
 		Dependencies: []decode.Dependency{
-			{Names: []string{format.ETHER8023_FRAME}, Group: &pcapngEther8023Format},
+			{Names: []string{format.LINK_FRAME}, Group: &pcapngLinkFrameFormat},
-			{Names: []string{format.SLL_PACKET}, Group: &pcapngSLLPacketFormat},
-			{Names: []string{format.SLL2_PACKET}, Group: &pcapngSLL2PacketFormat},
 			{Names: []string{format.TCP_STREAM}, Group: &pcapngTCPStreamFormat},
 			{Names: []string{format.IPV4_PACKET}, Group: &pcapngIPvPacket4Format},
 		},
@@ -244,12 +240,12 @@ var blockFns = map[uint64]func(d *decode.D, dc *decodeContext){
 		if fn, ok := linkToDecodeFn[linkType]; ok {
 			// TODO: report decode errors
 			_ = fn(dc.flowDecoder, bs)
-			_ = fn(dc.flowDecoder, bs)
 		}
 
-		if g, ok := linkToFormat[linkType]; ok {
+		if dv, _, _ := d.TryFieldFormatLen("packet", int64(capturedLength)*8, pcapngLinkFrameFormat, format.LinkFrameIn{
-			d.FieldFormatLen("packet", int64(capturedLength)*8, *g, nil)
+			Type:         linkType,
-		} else {
+			LittleEndian: d.Endian == decode.LittleEndian,
+		}); dv == nil {
 			d.FieldRawLen("packet", int64(capturedLength)*8)
 		}
 

format/pcap/shared.go

@@ -9,14 +9,8 @@ import (
 	"github.com/wader/fq/pkg/decode"
 )
 
-// TODO: is shared between pcap and pcapng
-var linkToFormat = map[int]*decode.Group{
-	format.LinkTypeETHERNET:   &pcapngEther8023Format,
-	format.LinkTypeLINUX_SLL:  &pcapngSLLPacketFormat,
-	format.LinkTypeLINUX_SLL2: &pcapngSLL2PacketFormat,
-}
-
 var linkToDecodeFn = map[int]func(fd *flowsdecoder.Decoder, bs []byte) error{
+	format.LinkTypeNULL:      (*flowsdecoder.Decoder).LoopbackFrame,
 	format.LinkTypeETHERNET:  (*flowsdecoder.Decoder).EthernetFrame,
 	format.LinkTypeLINUX_SLL: (*flowsdecoder.Decoder).SLLPacket,
 	format.LinkTypeLINUX_SLL2: func(fd *flowsdecoder.Decoder, bs []byte) error {

format/pcap/testdata/many_interfaces.fqtest

@@ -490,9 +490,32 @@ $ fq -d pcapng verbose /many_interfaces.pcapng
 0x0750|                        c0 6d 62 c9            |        .mb.    |        timestamp_low: 3378671040 0x758-0x75b.7 (4)
 0x0750|                                    a8 00 00 00|            ....|        capture_packet_length: 168 0x75c-0x75f.7 (4)
 0x0760|a8 00 00 00                                    |....            |        original_packet_length: 168 0x760-0x763.7 (4)
-0x0760|            02 00 00 00 45 00 00 a4 c6 ce 00 00|    ....E.......|        packet: raw bits 0x764-0x80b.7 (168)
+      |                                               |                |        packet{}: (bsd_loopback_frame) 0x764-0x80b.7 (168)
-0x0770|40 11 f1 47 c0 a8 01 8b ff ff ff ff 44 5c 44 5c|@..G........D\D\|
+0x0760|            02 00 00 00                        |    ....        |          network_layer: "ipv4" (0x2) (Internet protocol v4) 0x764-0x767.7 (4)
-*     |until 0x80b.7 (168)                            |                |
+      |                                               |                |          packet{}: (ipv4_packet) 0x768-0x80b.7 (164)
+0x0760|                        45                     |        E       |            version: 4 0x768-0x768.3 (0.4)
+0x0760|                        45                     |        E       |            ihl: 5 0x768.4-0x768.7 (0.4)
+0x0760|                           00                  |         .      |            dscp: 0 0x769-0x769.5 (0.6)
+0x0760|                           00                  |         .      |            ecn: 0 0x769.6-0x769.7 (0.2)
+0x0760|                              00 a4            |          ..    |            total_length: 164 0x76a-0x76b.7 (2)
+0x0760|                                    c6 ce      |            ..  |            identification: 50894 0x76c-0x76d.7 (2)
+0x0760|                                          00   |              . |            reserved: 0 0x76e-0x76e (0.1)
+0x0760|                                          00   |              . |            dont_fragment: false 0x76e.1-0x76e.1 (0.1)
+0x0760|                                          00   |              . |            more_fragments: false 0x76e.2-0x76e.2 (0.1)
+0x0760|                                          00 00|              ..|            fragment_offset: 0 0x76e.3-0x76f.7 (1.5)
+0x0770|40                                             |@               |            ttl: 64 0x770-0x770.7 (1)
+0x0770|   11                                          | .              |            protocol: "udp" (17) (User datagram protocol) 0x771-0x771.7 (1)
+0x0770|      f1 47                                    |  .G            |            header_checksum: 0xf147 (valid) 0x772-0x773.7 (2)
+0x0770|            c0 a8 01 8b                        |    ....        |            source_ip: "192.168.1.139" (0xc0a8018b) 0x774-0x777.7 (4)
+0x0770|                        ff ff ff ff            |        ....    |            destination_ip: "255.255.255.255" (0xffffffff) 0x778-0x77b.7 (4)
+      |                                               |                |            data{}: (udp_datagram) 0x77c-0x80b.7 (144)
+0x0770|                                    44 5c      |            D\  |              source_port: 17500 0x77c-0x77d.7 (2)
+0x0770|                                          44 5c|              D\|              destination_port: 17500 0x77e-0x77f.7 (2)
+0x0780|00 90                                          |..              |              length: 144 0x780-0x781.7 (2)
+0x0780|      ba 03                                    |  ..            |              checksum: 0xba03 0x782-0x783.7 (2)
+0x0780|            7b 22 68 6f 73 74 5f 69 6e 74 22 3a|    {"host_int":|              data: raw bits 0x784-0x80b.7 (136)
+0x0790|20 34 30 39 34 35 31 34 34 38 33 2c 20 22 76 65| 4094514483, "ve|
+*     |until 0x80b.7 (136)                            |                |
       |                                               |                |        padding: raw bits 0x80c-NA (0)
       |                                               |                |        options[0:0]: 0x80c-NA (0)
 0x0800|                                    c8 00 00 00|            ....|        footer_length: 200 0x80c-0x80f.7 (4)
@@ -504,9 +527,32 @@ $ fq -d pcapng verbose /many_interfaces.pcapng
 0x0820|be 6e 62 c9                                    |.nb.            |        timestamp_low: 3378671294 0x820-0x823.7 (4)
 0x0820|            a8 00 00 00                        |    ....        |        capture_packet_length: 168 0x824-0x827.7 (4)
 0x0820|                        a8 00 00 00            |        ....    |        original_packet_length: 168 0x828-0x82b.7 (4)
-0x0820|                                    02 00 00 00|            ....|        packet: raw bits 0x82c-0x8d3.7 (168)
+      |                                               |                |        packet{}: (bsd_loopback_frame) 0x82c-0x8d3.7 (168)
-0x0830|45 00 00 a4 60 b4 00 00 40 11 94 ba c0 a8 01 8b|E...`...@.......|
+0x0820|                                    02 00 00 00|            ....|          network_layer: "ipv4" (0x2) (Internet protocol v4) 0x82c-0x82f.7 (4)
-*     |until 0x8d3.7 (168)                            |                |
+      |                                               |                |          packet{}: (ipv4_packet) 0x830-0x8d3.7 (164)
+0x0830|45                                             |E               |            version: 4 0x830-0x830.3 (0.4)
+0x0830|45                                             |E               |            ihl: 5 0x830.4-0x830.7 (0.4)
+0x0830|   00                                          | .              |            dscp: 0 0x831-0x831.5 (0.6)
+0x0830|   00                                          | .              |            ecn: 0 0x831.6-0x831.7 (0.2)
+0x0830|      00 a4                                    |  ..            |            total_length: 164 0x832-0x833.7 (2)
+0x0830|            60 b4                              |    `.          |            identification: 24756 0x834-0x835.7 (2)
+0x0830|                  00                           |      .         |            reserved: 0 0x836-0x836 (0.1)
+0x0830|                  00                           |      .         |            dont_fragment: false 0x836.1-0x836.1 (0.1)
+0x0830|                  00                           |      .         |            more_fragments: false 0x836.2-0x836.2 (0.1)
+0x0830|                  00 00                        |      ..        |            fragment_offset: 0 0x836.3-0x837.7 (1.5)
+0x0830|                        40                     |        @       |            ttl: 64 0x838-0x838.7 (1)
+0x0830|                           11                  |         .      |            protocol: "udp" (17) (User datagram protocol) 0x839-0x839.7 (1)
+0x0830|                              94 ba            |          ..    |            header_checksum: 0x94ba (valid) 0x83a-0x83b.7 (2)
+0x0830|                                    c0 a8 01 8b|            ....|            source_ip: "192.168.1.139" (0xc0a8018b) 0x83c-0x83f.7 (4)
+0x0840|c0 a8 01 ff                                    |....            |            destination_ip: "192.168.1.255" (0xc0a801ff) 0x840-0x843.7 (4)
+      |                                               |                |            data{}: (udp_datagram) 0x844-0x8d3.7 (144)
+0x0840|            44 5c                              |    D\          |              source_port: 17500 0x844-0x845.7 (2)
+0x0840|                  44 5c                        |      D\        |              destination_port: 17500 0x846-0x847.7 (2)
+0x0840|                        00 90                  |        ..      |              length: 144 0x848-0x849.7 (2)
+0x0840|                              f7 5b            |          .[    |              checksum: 0xf75b 0x84a-0x84b.7 (2)
+0x0840|                                    7b 22 68 6f|            {"ho|              data: raw bits 0x84c-0x8d3.7 (136)
+0x0850|73 74 5f 69 6e 74 22 3a 20 34 30 39 34 35 31 34|st_int": 4094514|
+*     |until 0x8d3.7 (136)                            |                |
       |                                               |                |        padding: raw bits 0x8d4-NA (0)
       |                                               |                |        options[0:0]: 0x8d4-NA (0)
 0x08d0|            c8 00 00 00                        |    ....        |        footer_length: 200 0x8d4-0x8d7.7 (4)

pkg/interp/testdata/args.fqtest

@@ -65,6 +65,7 @@ avc_nalu             H.264/AVC Network Access Layer Unit
 avc_pps              H.264/AVC Picture Parameter Set
 avc_sei              H.264/AVC Supplemental Enhancement Information
 avc_sps              H.264/AVC Sequence Parameter Set
+bsd_loopback_frame   BSD loopback frame
 bzip2                bzip2 compression
 dns                  DNS packet
 dns_tcp              DNS packet (TCP)