151 lines
3.7 KiB
Go
151 lines
3.7 KiB
Go
package discovery
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import (
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"fmt"
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"net"
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"time"
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"git.loafle.net/commons_go/logging"
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"git.loafle.net/commons_go/util/net/cidr"
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"github.com/google/gopacket"
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"github.com/google/gopacket/layers"
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"git.loafle.net/overflow/overflow_discovery/api/module/discovery/model"
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"git.loafle.net/overflow/overflow_discovery/commons/pcap"
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)
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func scanHost(zone *model.Zone, dh *model.DiscoveryHost, resultChan chan interface{}, errChan chan error, doneChan chan<- struct{}) {
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ps, err := pcap.RetainScanner(zone)
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if nil != err {
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errChan <- fmt.Errorf("Discovery: Cannot retain pcap instance %v", err)
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// doneChan <- struct{}{}
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return
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}
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cr, err := cidr.NewCIDRRanger(zone.Network)
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if nil != err {
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errChan <- err
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return
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}
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hostRanges, err := getTargetHostRange(dh, cr)
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if nil != err {
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errChan <- err
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return
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}
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arpChan := ps.OpenARP()
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defer func() {
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if nil != ps {
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ps.CloseARP(arpChan)
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pcap.ReleaseScanner(zone)
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}
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doneChan <- struct{}{}
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}()
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go func() {
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hosts := make(map[string]*model.Host)
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for {
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select {
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case packet, ok := <-arpChan:
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if !ok {
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logging.Logger().Debug(fmt.Sprintf("Discovery: arp channel is closed"))
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return
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}
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if h := handlePacketARP(zone, cr, hosts, packet); nil != h {
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logging.Logger().Debug(fmt.Sprintf("Discovery: Host[%v] is founded", h))
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}
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}
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}
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}()
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if err := sendARP(ps, zone, hostRanges); nil != err {
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errChan <- err
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return
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}
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time.Sleep(10 * time.Second)
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}
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func handlePacketARP(zone *model.Zone, cr cidr.CIDRRanger, hosts map[string]*model.Host, packet *layers.ARP) *model.Host {
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if packet.Operation != layers.ARPReply {
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return nil
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}
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// logging.Logger().Debug(fmt.Sprintf("Discovery: arp packet %v", packet))
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ip := net.IP(packet.SourceProtAddress)
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if _, ok := hosts[ip.String()]; ok || !cr.Contains(ip) {
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return nil
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}
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h := &model.Host{}
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h.IP = ip.String()
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h.Mac = net.HardwareAddr(packet.SourceHwAddress).String()
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h.Zone = zone
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hosts[ip.String()] = h
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return h
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}
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func sendARP(ps pcap.PCapScanner, zone *model.Zone, hostRanges []net.IP) error {
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hwAddr, err := net.ParseMAC(zone.Mac)
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if nil != err {
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return err
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}
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ip := net.ParseIP(zone.IP)
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if nil == ip {
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return fmt.Errorf("Discovery: IP(%s) of zone is not valid", zone.IP)
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}
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ethPacket := makePacketEthernet(hwAddr)
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arpPacket := makePacketARP(hwAddr, ip.To4())
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opts := gopacket.SerializeOptions{FixLengths: true, ComputeChecksums: true}
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buf := gopacket.NewSerializeBuffer()
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for _, targetHost := range hostRanges {
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arpPacket.DstProtAddress = []byte(targetHost)
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// log.Printf("ARP:%v", arpPacket)
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gopacket.SerializeLayers(buf, opts, ðPacket, &arpPacket)
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if err := ps.WritePacketData(buf.Bytes()); err != nil {
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return err
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}
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time.Sleep(time.Microsecond * 100)
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}
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return nil
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}
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func getTargetHostRange(dh *model.DiscoveryHost, cr cidr.CIDRRanger) ([]net.IP, error) {
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excludeIPs := make([]net.IP, 0)
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for _, eHost := range dh.ExcludeHosts {
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eIP := net.ParseIP(eHost)
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if nil == eIP {
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return nil, fmt.Errorf("Discovery: IP(%v) of exclude host is not valid", eHost)
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}
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excludeIPs = append(excludeIPs, eIP)
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}
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ranges := cr.Range(excludeIPs)
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return ranges, nil
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}
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func makePacketEthernet(hw net.HardwareAddr) layers.Ethernet {
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return layers.Ethernet{
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SrcMAC: hw,
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DstMAC: net.HardwareAddr{0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
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EthernetType: layers.EthernetTypeARP,
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}
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}
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func makePacketARP(hw net.HardwareAddr, ip net.IP) layers.ARP {
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return layers.ARP{
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AddrType: layers.LinkTypeEthernet,
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Protocol: layers.EthernetTypeIPv4,
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HwAddressSize: 6,
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ProtAddressSize: 4,
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Operation: layers.ARPRequest,
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SourceHwAddress: []byte(hw),
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SourceProtAddress: []byte(ip),
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DstHwAddress: []byte{0, 0, 0, 0, 0, 0},
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}
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}
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