132 lines
2.6 KiB
Go
132 lines
2.6 KiB
Go
package pndp
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import (
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"bytes"
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"fmt"
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"net"
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"sync"
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"syscall"
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)
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func respond(iface string, requests chan *ndpRequest, respondType ndpType, filter []*net.IPNet, autoSense string, stopWG *sync.WaitGroup, stopChan chan struct{}) {
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stopWG.Add(1)
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defer stopWG.Done()
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fd, err := syscall.Socket(syscall.AF_INET6, syscall.SOCK_RAW, syscall.IPPROTO_RAW)
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if err != nil {
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panic(err)
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}
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defer syscall.Close(fd)
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err = syscall.BindToDevice(fd, iface)
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if err != nil {
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panic(err)
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}
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niface, err := net.InterfaceByName(iface)
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if err != nil {
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panic(err.Error())
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}
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var result = emptyIpv6
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ifaceaddrs, err := niface.Addrs()
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for _, n := range ifaceaddrs {
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tip, _, err := net.ParseCIDR(n.String())
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if err != nil {
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break
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}
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if isIpv6(tip.String()) {
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if tip.IsGlobalUnicast() {
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result = tip
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_, tnet, _ := net.ParseCIDR("fc00::/7")
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if !tnet.Contains(tip) {
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break
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}
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}
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}
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}
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for {
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var n *ndpRequest
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select {
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case <-stopChan:
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return
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case n = <-requests:
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}
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if autoSense != "" {
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autoiface, err := net.InterfaceByName(autoSense)
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if err != nil {
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panic(err)
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}
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autoifaceaddrs, err := autoiface.Addrs()
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for _, n := range autoifaceaddrs {
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_, anet, err := net.ParseCIDR(n.String())
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if err != nil {
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break
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}
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if isIpv6(anet.String()) {
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filter = append(filter, anet)
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}
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}
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}
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if filter != nil {
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ok := false
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for _, i := range filter {
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if i.Contains(n.answeringForIP) {
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if GlobalDebug {
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fmt.Println("Responded for whitelisted IP", n.answeringForIP)
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}
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ok = true
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break
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}
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}
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if !ok {
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continue
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}
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}
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if GlobalDebug {
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fmt.Println("Getting ready to send packet of type", respondType, "out on interface", iface)
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}
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if n.sourceIface == iface {
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pkt(fd, result, n.srcIP, n.answeringForIP, niface.HardwareAddr, respondType)
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} else {
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if !bytes.Equal(n.mac, n.receivedIfaceMac) {
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pkt(fd, n.srcIP, n.dstIP, n.answeringForIP, niface.HardwareAddr, respondType)
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}
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}
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}
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}
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func pkt(fd int, ownIP []byte, dstIP []byte, tgtip []byte, mac []byte, respondType ndpType) {
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v6, err := newIpv6Header(ownIP, dstIP)
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if err != nil {
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return
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}
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NDPa, err := newNdpPacket(tgtip, mac, respondType)
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if err != nil {
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return
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}
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v6.addPayload(NDPa)
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response := v6.constructPacket()
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var t [16]byte
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copy(t[:], dstIP)
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d := syscall.SockaddrInet6{
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Port: 0,
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Addr: t,
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}
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if GlobalDebug {
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fmt.Println("Sending packet of type", respondType, "to")
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fmt.Printf("% X\n", t)
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}
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err = syscall.Sendto(fd, response, 0, &d)
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if err != nil {
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fmt.Println(err.Error())
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}
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}
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