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producer: fix sFlow parsing when sampled header is truncated #139

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producer: fix sFlow parsing when sampled header is truncated #139

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198 changes: 96 additions & 102 deletions producer/producer_sf.go
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Original file line number Diff line number Diff line change
Expand Up @@ -61,137 +61,131 @@ func ParseEthernetHeader(flowMessage *flowmessage.FlowMessage, data []byte, conf
MapCustom(flowMessage, extracted, configLayer.Destination)
}

if len(data) < offset {
return
}
etherType := data[12:14]

dstMac = binary.BigEndian.Uint64(append([]byte{0, 0}, data[0:6]...))
srcMac = binary.BigEndian.Uint64(append([]byte{0, 0}, data[6:12]...))
(*flowMessage).SrcMac = srcMac
(*flowMessage).DstMac = dstMac

encap := true
iterations := 0
for encap && iterations <= 1 {
encap = false

if etherType[0] == 0x81 && etherType[1] == 0x0 { // VLAN 802.1Q
if etherType[0] == 0x81 && etherType[1] == 0x0 { // VLAN 802.1Q
offset += 4
if len(data) >= offset {
(*flowMessage).VlanId = uint32(binary.BigEndian.Uint16(data[14:16]))
offset += 4
etherType = data[16:18]
}
}

if etherType[0] == 0x88 && etherType[1] == 0x47 { // MPLS
iterateMpls := true
hasMpls = true
for iterateMpls {
if len(data) < offset+5 {
iterateMpls = false
break
}
label := binary.BigEndian.Uint32(append([]byte{0}, data[offset:offset+3]...)) >> 4
//exp := data[offset+2] > 1
bottom := data[offset+2] & 1
mplsTtl := data[offset+3]
if etherType[0] == 0x88 && etherType[1] == 0x47 { // MPLS
hasMpls = true
for {
if len(data) < offset+5 {
offset += 4
break
}
label := binary.BigEndian.Uint32(append([]byte{0}, data[offset:offset+3]...)) >> 4
//exp := data[offset+2] > 1
bottom := data[offset+2] & 1
mplsTtl := data[offset+3]
offset += 4

if bottom == 1 || label <= 15 || offset > len(data) {
if data[offset]&0xf0>>4 == 4 {
etherType = []byte{0x8, 0x0}
} else if data[offset]&0xf0>>4 == 6 {
etherType = []byte{0x86, 0xdd}
}
iterateMpls = false
}
if countMpls == 0 {
firstLabelMpls = label
firstTtlMpls = mplsTtl
} else if countMpls == 1 {
secondLabelMpls = label
secondTtlMpls = mplsTtl
} else if countMpls == 2 {
thirdLabelMpls = label
thirdTtlMpls = mplsTtl
} else {
lastLabelMpls = label
lastTtlMpls = mplsTtl
}
countMpls++

if countMpls == 0 {
firstLabelMpls = label
firstTtlMpls = mplsTtl
} else if countMpls == 1 {
secondLabelMpls = label
secondTtlMpls = mplsTtl
} else if countMpls == 2 {
thirdLabelMpls = label
thirdTtlMpls = mplsTtl
} else {
lastLabelMpls = label
lastTtlMpls = mplsTtl
if bottom == 1 || label <= 15 || offset > len(data) {
if data[offset]&0xf0>>4 == 4 {
etherType = []byte{0x8, 0x0}
} else if data[offset]&0xf0>>4 == 6 {
etherType = []byte{0x86, 0xdd}
}
countMpls++
break
}
}
}

for _, configLayer := range GetSFlowConfigLayer(config, 3) {
extracted := GetBytes(data, offset*8+configLayer.Offset, configLayer.Length)
MapCustom(flowMessage, extracted, configLayer.Destination)
}

if etherType[0] == 0x8 && etherType[1] == 0x0 { // IPv4
if len(data) >= offset+20 {
nextHeader = data[offset+9]
srcIP = data[offset+12 : offset+16]
dstIP = data[offset+16 : offset+20]
tos = data[offset+1]
ttl = data[offset+8]

identification = binary.BigEndian.Uint16(data[offset+4 : offset+6])
fragOffset = binary.BigEndian.Uint16(data[offset+6 : offset+8])

offset += 20
}
} else if etherType[0] == 0x86 && etherType[1] == 0xdd { // IPv6
if len(data) >= offset+40 {
nextHeader = data[offset+6]
srcIP = data[offset+8 : offset+24]
dstIP = data[offset+24 : offset+40]

tostmp := uint32(binary.BigEndian.Uint16(data[offset : offset+2]))
tos = uint8(tostmp & 0x0ff0 >> 4)
ttl = data[offset+7]

flowLabel = binary.BigEndian.Uint32(data[offset : offset+4])
for _, configLayer := range GetSFlowConfigLayer(config, 3) {
extracted := GetBytes(data, offset*8+configLayer.Offset, configLayer.Length)
MapCustom(flowMessage, extracted, configLayer.Destination)
}

offset += 40
if etherType[0] == 0x8 && etherType[1] == 0x0 { // IPv4
if len(data) >= offset+20 {
nextHeader = data[offset+9]
srcIP = data[offset+12 : offset+16]
dstIP = data[offset+16 : offset+20]
tos = data[offset+1]
ttl = data[offset+8]

identification = binary.BigEndian.Uint16(data[offset+4 : offset+6])
fragOffset = binary.BigEndian.Uint16(data[offset+6 : offset+8])

ihl := int((data[0] & 0xf) * 4)
offset += ihl
} else {
offset += 20
}
} else if etherType[0] == 0x86 && etherType[1] == 0xdd { // IPv6
if len(data) >= offset+40 {
nextHeader = data[offset+6]
srcIP = data[offset+8 : offset+24]
dstIP = data[offset+24 : offset+40]

}
} else if etherType[0] == 0x8 && etherType[1] == 0x6 { // ARP
} /*else {
return errors.New(fmt.Sprintf("Unknown EtherType: %v\n", etherType))
} */
tostmp := uint32(binary.BigEndian.Uint16(data[offset : offset+2]))
tos = uint8(tostmp & 0x0ff0 >> 4)
ttl = data[offset+7]

for _, configLayer := range GetSFlowConfigLayer(config, 4) {
extracted := GetBytes(data, offset*8+configLayer.Offset, configLayer.Length)
MapCustom(flowMessage, extracted, configLayer.Destination)
flowLabel = binary.BigEndian.Uint32(data[offset : offset+4])
}
offset += 40
}

appOffset := 0
if len(data) >= offset+4 && (nextHeader == 17 || nextHeader == 6) {
srcPort = binary.BigEndian.Uint16(data[offset+0 : offset+2])
dstPort = binary.BigEndian.Uint16(data[offset+2 : offset+4])
}
for _, configLayer := range GetSFlowConfigLayer(config, 4) {
extracted := GetBytes(data, offset*8+configLayer.Offset, configLayer.Length)
MapCustom(flowMessage, extracted, configLayer.Destination)
}

if nextHeader == 17 {
appOffset = 8
}
appOffset := 0
if len(data) >= offset+4 && (nextHeader == 17 || nextHeader == 6) {
srcPort = binary.BigEndian.Uint16(data[offset+0 : offset+2])
dstPort = binary.BigEndian.Uint16(data[offset+2 : offset+4])
}

if len(data) > offset+13 && nextHeader == 6 {
tcpflags = data[offset+13]
if nextHeader == 17 {
appOffset = 8
}

appOffset = int(data[13]>>4) * 4
}
if len(data) > offset+13 && nextHeader == 6 {
tcpflags = data[offset+13]

// ICMP and ICMPv6
if len(data) >= offset+2 && (nextHeader == 1 || nextHeader == 58) {
(*flowMessage).IcmpType = uint32(data[offset+0])
(*flowMessage).IcmpCode = uint32(data[offset+1])
}
appOffset = int(data[offset+12]>>4) * 4
}

if appOffset > 0 {
for _, configLayer := range GetSFlowConfigLayer(config, 7) {
extracted := GetBytes(data, (offset+appOffset)*8+configLayer.Offset, configLayer.Length)
MapCustom(flowMessage, extracted, configLayer.Destination)
}
}
// ICMP and ICMPv6
if len(data) >= offset+2 && (nextHeader == 1 || nextHeader == 58) {
(*flowMessage).IcmpType = uint32(data[offset+0])
(*flowMessage).IcmpCode = uint32(data[offset+1])
}

iterations++
if appOffset > 0 {
for _, configLayer := range GetSFlowConfigLayer(config, 7) {
extracted := GetBytes(data, (offset+appOffset)*8+configLayer.Offset, configLayer.Length)
MapCustom(flowMessage, extracted, configLayer.Destination)
}
}

(*flowMessage).HasMpls = hasMpls
Expand Down
23 changes: 22 additions & 1 deletion producer/producer_test.go
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Original file line number Diff line number Diff line change
@@ -1,10 +1,13 @@
package producer

import (
"encoding/binary"
"net"
"testing"

"github.com/netsampler/goflow2/decoders/netflow"
"github.com/netsampler/goflow2/decoders/sflow"
flowmessage "github.com/netsampler/goflow2/pb"
"github.com/stretchr/testify/assert"
)

Expand Down Expand Up @@ -73,8 +76,26 @@ func TestProcessMessageSFlow(t *testing.T) {
},
},
}
_, err := ProcessMessageSFlow(pkt)
flowMessages, err := ProcessMessageSFlow(pkt)
assert.Nil(t, err)
assert.Equal(t, flowMessages[0], &flowmessage.FlowMessage{
Type: flowmessage.FlowMessage_SFLOW_5,
SamplingRate: 1,
Bytes: 10,
Packets: 1,
SrcAddr: net.ParseIP("fd01::ff01:8210:cdff:ff1c:0:150"),
DstAddr: net.ParseIP("fd01::ff01:1:2ff:ff93:0:246"),
Etype: 0x86dd,
Proto: 6,
SrcPort: 53194,
DstPort: 80,
SrcMac: binary.BigEndian.Uint64([]byte{0, 0, 0xff, 0xab, 0xcd, 0xef, 0xab, 0xbc}),
DstMac: binary.BigEndian.Uint64([]byte{0, 0, 0xff, 0xab, 0xcd, 0xef, 0xab, 0xcd}),
IpTos: 2,
IpTtl: 64,
TcpFlags: 24,
Ipv6FlowLabel: 967916,
})
}

func TestExpandedSFlowDecode(t *testing.T) {
Expand Down