/
main.go
487 lines (458 loc) · 15.4 KB
/
main.go
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package main
import (
"encoding/json"
"flag"
"fmt"
"log"
"net"
"os"
"github.com/google/gopacket"
"github.com/google/gopacket/layers"
"github.com/google/gopacket/pcap"
)
var (
snapshotLen int32 = 65535
err error
handle *pcap.Handle
packetCount int
)
const hexDigit = "0123456789abcdef"
func hardwareAddrString(a []byte) string {
if len(a) == 0 {
return ""
}
buf := make([]byte, 0, len(a)*3-1)
for i, b := range a {
if i > 0 {
buf = append(buf, ':')
}
buf = append(buf, hexDigit[b>>4])
buf = append(buf, hexDigit[b&0xF])
}
return string(buf)
}
func printBiteSizedJSON(record map[string]interface{}) {
b, err := json.Marshal(record)
if err != nil {
fmt.Println(err)
return
}
fmt.Println(string(b))
}
var (
file string
iface string
filter string
listDevs bool
biteSized bool
promiscuous bool
jsonIsEvil bool
)
func init() {
// Use the first, non-loopback interface if no interface is given.
// https://github.com/picatz/iface/blob/master/iface.go#L90
ifaces, err := net.Interfaces()
if err != nil {
log.Fatal(err)
}
for _, ifc := range ifaces {
// must have mac address, FlagUp and FlagBroadcast
if ifc.HardwareAddr != nil && ifc.Flags&net.FlagUp != 0 && ifc.Flags&net.FlagBroadcast != 0 {
iface = ifc.Name
break
}
}
flag.StringVar(&file, "file", "", "pcap file to read packets from")
flag.StringVar(&filter, "filter", "", "apply bpf filter to capture or pcap file")
flag.StringVar(&iface, "interface", iface, "network interface to listen on")
flag.BoolVar(&listDevs, "list-devs", false, "list network interfaces")
flag.BoolVar(&jsonIsEvil, "json-is-evil", false, "don't do any of that json stuff")
flag.BoolVar(&promiscuous, "promiscuous", false, "capture in promiscuous mode")
// stackdriver has a 100k log entry limit...
flag.BoolVar(&biteSized, "bite-sized", false, "split packet json information into smaller chunks, spanning multiple lines")
flag.Parse()
if listDevs {
// Find all devices
devices, err := pcap.FindAllDevs()
if err != nil {
log.Fatal(err)
os.Exit(1)
}
// Print device information
fmt.Println("Devices found:")
for _, device := range devices {
fmt.Println("\nName: ", device.Name)
fmt.Println("Description: ", device.Description)
fmt.Println("Devices addresses: ", device.Description)
for _, address := range device.Addresses {
fmt.Println("- IP address: ", address.IP)
fmt.Println("- Subnet mask: ", address.Netmask)
}
}
os.Exit(0)
}
}
func main() {
var pcapHandle *pcap.Handle
var deviceName string
var deviceDesc string
var deviceAddrs = []map[string]string{}
if file != "" {
pcapHandle, err = pcap.OpenOffline(file)
if err != nil {
log.Fatal(err)
os.Exit(1)
}
} else {
// Find all devices
devices, err := pcap.FindAllDevs()
if err != nil {
log.Fatal(err)
}
for _, device := range devices {
if device.Name == iface {
pcapHandle, err = pcap.OpenLive(device.Name, snapshotLen, promiscuous, pcap.BlockForever)
if err != nil {
log.Fatal(err)
}
deviceName = device.Name
deviceDesc = device.Description
for _, address := range device.Addresses {
deviceAddrs = append(deviceAddrs, map[string]string{
"ip_address": address.IP.String(),
"subnet_mask": address.Netmask.String(),
})
}
}
}
}
defer pcapHandle.Close()
if filter != "" {
err := pcapHandle.SetBPFFilter(filter)
if err != nil {
log.Fatal(err)
}
}
if biteSized {
// Use the handle as a packet source to process all packets
packetSource := gopacket.NewPacketSource(pcapHandle, pcapHandle.LinkType())
for packet := range packetSource.Packets() {
packetCount++
record := make(map[string]interface{})
metaData := packet.Metadata()
record["packet"] = packetCount
record["time"] = metaData.Timestamp
record["truncated"] = metaData.Truncated
record["length"] = metaData.Length
record["device_name"] = deviceName
record["device_description"] = deviceDesc
record["device_addresses"] = deviceName
printBiteSizedJSON(record)
for _, layer := range packet.Layers() {
switch layer.LayerType() {
case layers.LayerTypeEthernet:
record := make(map[string]interface{})
record["packet"] = packetCount
record["eth"] = true
eth, _ := layer.(*layers.Ethernet)
record["src"] = eth.SrcMAC.String()
record["dst"] = eth.DstMAC.String()
record["type"] = eth.EthernetType
printBiteSizedJSON(record)
case layers.LayerTypeIPv4:
record := make(map[string]interface{})
record["packet"] = packetCount
record["ip"] = true
ipv4, _ := layer.(*layers.IPv4)
record["version"] = ipv4.Version
record["ihl"] = ipv4.IHL
record["tos"] = ipv4.TOS
record["length"] = ipv4.Length
record["id"] = ipv4.Id
record["flags"] = ipv4.Flags.String()
record["frag_offset"] = ipv4.FragOffset
record["ttl"] = ipv4.TTL
record["protocol"] = ipv4.Protocol
record["checksum"] = ipv4.Checksum
record["src_ip"] = ipv4.SrcIP.String()
record["dst_ip"] = ipv4.DstIP.String()
options := []string{}
for _, option := range ipv4.Options {
options = append(options, option.String())
}
record["options"] = options
record["padding"] = ipv4.Padding
printBiteSizedJSON(record)
case layers.LayerTypeTCP:
record := make(map[string]interface{})
record["packet"] = packetCount
record["tcp"] = true
tcp, _ := layer.(*layers.TCP)
record["src_port"] = tcp.SrcPort
record["dst_port"] = tcp.DstPort
record["seq"] = tcp.Seq
record["ack"] = tcp.Ack
record["data_offset"] = tcp.DataOffset
record["fin"] = tcp.FIN
record["syn"] = tcp.SYN
record["rst"] = tcp.RST
record["psh"] = tcp.PSH
record["ack"] = tcp.ACK
record["urg"] = tcp.URG
record["ece"] = tcp.ECE
record["cwr"] = tcp.CWR
record["ns"] = tcp.NS
options := []string{}
for _, option := range tcp.Options {
options = append(options, option.String())
}
record["options"] = options
record["padding"] = tcp.Padding
record["payload"] = string(tcp.Payload)
record["payload_length"] = len(tcp.Payload)
printBiteSizedJSON(record)
case layers.LayerTypeUDP:
record := make(map[string]interface{})
record["packet"] = packetCount
record["udp"] = true
udp, _ := layer.(*layers.UDP)
record["src_port"] = udp.SrcPort
record["dst_port"] = udp.DstPort
record["checksum"] = udp.Checksum
record["payload"] = string(udp.Payload)
record["payload_length"] = len(udp.Payload)
printBiteSizedJSON(record)
case layers.LayerTypeICMPv4:
record := make(map[string]interface{})
record["packet"] = packetCount
record["icmp"] = true
icmpv4, _ := layer.(*layers.ICMPv4)
record["type_code"] = icmpv4.TypeCode.String()
record["checksum"] = icmpv4.Checksum
record["id"] = icmpv4.Id
record["seq"] = icmpv4.Seq
record["payload"] = string(icmpv4.Payload)
printBiteSizedJSON(record)
case layers.LayerTypeARP:
record := make(map[string]interface{})
record["packet"] = packetCount
record["arp"] = true
arp, _ := layer.(*layers.ARP)
record["addr_type"] = arp.AddrType
record["protocol"] = arp.Protocol
record["hw_address_size"] = arp.HwAddressSize
record["prot_address_size"] = arp.ProtAddressSize
record["operation"] = arp.Operation
record["source_hw_address"] = hardwareAddrString(arp.SourceHwAddress)
record["source_prot_address"] = net.IP(arp.SourceProtAddress).String()
record["dst_hw_address"] = hardwareAddrString(arp.DstHwAddress)
record["dst_prot_address"] = net.IP(arp.DstProtAddress).String()
record["payload"] = string(arp.Payload)
printBiteSizedJSON(record)
case layers.LayerTypeDNS:
record := make(map[string]interface{})
record["packet"] = packetCount
record["dns"] = true
dns, _ := layer.(*layers.DNS)
record["id"] = dns.ID
record["qr"] = dns.QR
record["op_code"] = dns.OpCode
record["aa"] = dns.AA
record["tc"] = dns.TC
record["rd"] = dns.RD
record["ra"] = dns.RA
record["z"] = dns.Z
record["response_code"] = dns.ResponseCode.String()
record["qd_count"] = dns.QDCount
record["an_count"] = dns.ANCount
record["ns_count"] = dns.NSCount
record["ar_count"] = dns.ARCount
questions := []map[string]interface{}{}
for _, q := range dns.Questions {
question := map[string]interface{}{}
question["name"] = string(q.Name)
question["type"] = q.Type.String()
question["class"] = q.Class.String()
questions = append(questions, question)
}
record["questions"] = questions
answers := []string{}
for _, a := range dns.Answers {
answers = append(answers, a.String())
}
record["answers"] = answers
authorities := []string{}
for _, a := range dns.Authorities {
authorities = append(authorities, a.String())
}
record["authorities"] = answers
additionals := []string{}
for _, a := range dns.Additionals {
additionals = append(additionals, a.String())
}
record["additionals"] = additionals
printBiteSizedJSON(record)
}
}
b, err := json.Marshal(record)
if err != nil {
fmt.Println(err)
return
}
fmt.Println(string(b))
}
} else if jsonIsEvil {
// Use the handle as a packet source to process all packets
packetSource := gopacket.NewPacketSource(pcapHandle, pcapHandle.LinkType())
for packet := range packetSource.Packets() {
fmt.Println(packet)
}
} else {
// Use the handle as a packet source to process all packets
packetSource := gopacket.NewPacketSource(pcapHandle, pcapHandle.LinkType())
for packet := range packetSource.Packets() {
packetCount++
record := make(map[string]map[string]interface{})
record["metadata"] = map[string]interface{}{}
metaData := packet.Metadata()
record["metadata"]["packet_number"] = packetCount
record["metadata"]["time"] = metaData.Timestamp
record["metadata"]["truncated"] = metaData.Truncated
record["metadata"]["length"] = metaData.Length
record["metadata"]["device_name"] = deviceName
record["metadata"]["device_description"] = deviceDesc
record["metadata"]["device_addresses"] = deviceName
for _, layer := range packet.Layers() {
switch layer.LayerType() {
case layers.LayerTypeEthernet:
eth, _ := layer.(*layers.Ethernet)
record["eth"] = make(map[string]interface{})
record["eth"]["src"] = eth.SrcMAC.String()
record["eth"]["dst"] = eth.DstMAC.String()
record["eth"]["type"] = eth.EthernetType
case layers.LayerTypeIPv4:
ipv4, _ := layer.(*layers.IPv4)
record["ipv4"] = make(map[string]interface{})
record["ipv4"]["version"] = ipv4.Version
record["ipv4"]["ihl"] = ipv4.IHL
record["ipv4"]["tos"] = ipv4.TOS
record["ipv4"]["length"] = ipv4.Length
record["ipv4"]["id"] = ipv4.Id
record["ipv4"]["flags"] = ipv4.Flags.String()
record["ipv4"]["frag_offset"] = ipv4.FragOffset
record["ipv4"]["ttl"] = ipv4.TTL
record["ipv4"]["protocol"] = ipv4.Protocol
record["ipv4"]["checksum"] = ipv4.Checksum
record["ipv4"]["src_ip"] = ipv4.SrcIP.String()
record["ipv4"]["dst_ip"] = ipv4.DstIP.String()
options := []string{}
for _, option := range ipv4.Options {
options = append(options, option.String())
}
record["ipv4"]["options"] = options
record["ipv4"]["padding"] = ipv4.Padding
case layers.LayerTypeTCP:
tcp, _ := layer.(*layers.TCP)
record["tcp"] = make(map[string]interface{})
record["tcp"]["src_port"] = tcp.SrcPort
record["tcp"]["dst_port"] = tcp.DstPort
record["tcp"]["seq"] = tcp.Seq
record["tcp"]["ack"] = tcp.Ack
record["tcp"]["data_offset"] = tcp.DataOffset
record["tcp"]["fin"] = tcp.FIN
record["tcp"]["syn"] = tcp.SYN
record["tcp"]["rst"] = tcp.RST
record["tcp"]["psh"] = tcp.PSH
record["tcp"]["ack"] = tcp.ACK
record["tcp"]["urg"] = tcp.URG
record["tcp"]["ece"] = tcp.ECE
record["tcp"]["cwr"] = tcp.CWR
record["tcp"]["ns"] = tcp.NS
options := []string{}
for _, option := range tcp.Options {
options = append(options, option.String())
}
record["tcp"]["options"] = options
record["tcp"]["padding"] = tcp.Padding
record["tcp"]["payload"] = string(tcp.Payload)
record["tcp"]["payload_length"] = len(tcp.Payload)
case layers.LayerTypeUDP:
udp, _ := layer.(*layers.UDP)
record["udp"] = make(map[string]interface{})
record["udp"]["src_port"] = udp.SrcPort
record["udp"]["dst_port"] = udp.DstPort
record["udp"]["checksum"] = udp.Checksum
record["udp"]["payload"] = string(udp.Payload)
record["udp"]["payload_length"] = len(udp.Payload)
case layers.LayerTypeICMPv4:
icmpv4, _ := layer.(*layers.ICMPv4)
record["icmpv4"] = make(map[string]interface{})
record["icmpv4"]["type_code"] = icmpv4.TypeCode.String()
record["icmpv4"]["checksum"] = icmpv4.Checksum
record["icmpv4"]["id"] = icmpv4.Id
record["icmpv4"]["seq"] = icmpv4.Seq
record["icmpv4"]["payload"] = string(icmpv4.Payload)
case layers.LayerTypeARP:
arp, _ := layer.(*layers.ARP)
record["arp"] = make(map[string]interface{})
record["arp"]["addr_type"] = arp.AddrType
record["arp"]["protocol"] = arp.Protocol
record["arp"]["hw_address_size"] = arp.HwAddressSize
record["arp"]["prot_address_size"] = arp.ProtAddressSize
record["arp"]["operation"] = arp.Operation
record["arp"]["source_hw_address"] = hardwareAddrString(arp.SourceHwAddress)
record["arp"]["source_prot_address"] = net.IP(arp.SourceProtAddress).String()
record["arp"]["dst_hw_address"] = hardwareAddrString(arp.DstHwAddress)
record["arp"]["dst_prot_address"] = net.IP(arp.DstProtAddress).String()
record["arp"]["payload"] = string(arp.Payload)
case layers.LayerTypeDNS:
dns, _ := layer.(*layers.DNS)
record["dns"] = make(map[string]interface{})
record["dns"]["id"] = dns.ID
record["dns"]["qr"] = dns.QR
record["dns"]["op_code"] = dns.OpCode
record["dns"]["authoritative_answer"] = dns.AA
record["dns"]["truncated"] = dns.TC
record["dns"]["recursion_desired"] = dns.RD
record["dns"]["recursion_available"] = dns.RA
record["dns"]["z"] = dns.Z
record["dns"]["response_code"] = dns.ResponseCode.String()
record["dns"]["qd_count"] = dns.QDCount
record["dns"]["an_count"] = dns.ANCount
record["dns"]["ns_count"] = dns.NSCount
record["dns"]["ar_count"] = dns.ARCount
questions := []map[string]interface{}{}
for _, q := range dns.Questions {
question := map[string]interface{}{}
question["name"] = string(q.Name)
question["type"] = q.Type.String()
question["class"] = q.Class.String()
questions = append(questions, question)
}
record["dns"]["questions"] = questions
answers := []string{}
for _, a := range dns.Answers {
answers = append(answers, a.String())
}
record["dns"]["answers"] = answers
authorities := []string{}
for _, a := range dns.Authorities {
authorities = append(authorities, a.String())
}
record["dns"]["authorities"] = answers
additionals := []string{}
for _, a := range dns.Additionals {
additionals = append(additionals, a.String())
}
record["dns"]["additionals"] = additionals
}
}
b, err := json.Marshal(record)
if err != nil {
fmt.Println(err)
return
}
fmt.Println(string(b))
}
}
}