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https://github.com/AdguardTeam/AdGuardHome.git
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update dhcp client
This commit is contained in:
Simon Zolin
parent
bbd0e2b4f1
commit
2acff7757b
4 changed files with 27 additions and 70 deletions
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@ -2,16 +2,14 @@ package dhcpd
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import (
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"bytes"
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"crypto/rand"
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"encoding/binary"
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"fmt"
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"math"
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"net"
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"os"
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"time"
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"github.com/AdguardTeam/golibs/log"
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"github.com/krolaw/dhcp4"
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"github.com/insomniacslk/dhcp/dhcpv4"
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"github.com/insomniacslk/dhcp/iana"
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"golang.org/x/net/ipv4"
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)
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@ -34,51 +32,17 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
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src := net.JoinHostPort(srcIP.String(), "68")
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dst := "255.255.255.255:67"
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// form a DHCP request packet, try to emulate existing client as much as possible
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xID := make([]byte, 4)
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n, err := rand.Read(xID)
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if n != 4 && err == nil {
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err = fmt.Errorf("Generated less than 4 bytes")
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}
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if err != nil {
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return false, wrapErrPrint(err, "Couldn't generate random bytes")
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}
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hostname, err := os.Hostname()
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if err != nil {
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return false, wrapErrPrint(err, "Couldn't get hostname")
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}
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requestList := []byte{
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byte(dhcp4.OptionSubnetMask),
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byte(dhcp4.OptionClasslessRouteFormat),
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byte(dhcp4.OptionRouter),
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byte(dhcp4.OptionDomainNameServer),
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byte(dhcp4.OptionDomainName),
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byte(dhcp4.OptionDomainSearch),
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252, // private/proxy autodiscovery
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95, // LDAP
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byte(dhcp4.OptionNetBIOSOverTCPIPNameServer),
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byte(dhcp4.OptionNetBIOSOverTCPIPNodeType),
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}
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maxUDPsizeRaw := make([]byte, 2)
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binary.BigEndian.PutUint16(maxUDPsizeRaw, 1500)
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leaseTimeRaw := make([]byte, 4)
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leaseTime := uint32(math.RoundToEven((time.Hour * 24 * 90).Seconds()))
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binary.BigEndian.PutUint32(leaseTimeRaw, leaseTime)
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options := []dhcp4.Option{
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{Code: dhcp4.OptionParameterRequestList, Value: requestList},
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{Code: dhcp4.OptionMaximumDHCPMessageSize, Value: maxUDPsizeRaw},
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{Code: dhcp4.OptionClientIdentifier, Value: append([]byte{0x01}, iface.HardwareAddr...)},
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{Code: dhcp4.OptionIPAddressLeaseTime, Value: leaseTimeRaw},
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{Code: dhcp4.OptionHostName, Value: []byte(hostname)},
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}
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packet := dhcp4.RequestPacket(dhcp4.Discover, iface.HardwareAddr, nil, xID, false, options)
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hostname, _ := os.Hostname()
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req, err := dhcpv4.NewDiscovery(iface.HardwareAddr)
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req.Options.Update(dhcpv4.OptClientIdentifier(iface.HardwareAddr))
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req.Options.Update(dhcpv4.OptHostName(hostname))
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// resolve 0.0.0.0:68
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udpAddr, err := net.ResolveUDPAddr("udp4", src)
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if err != nil {
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return false, wrapErrPrint(err, "Couldn't resolve UDP address %s", src)
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}
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// spew.Dump(udpAddr, err)
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if !udpAddr.IP.To4().Equal(srcIP) {
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return false, wrapErrPrint(err, "Resolved UDP address is not %s", src)
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@ -102,7 +66,7 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
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// send to 255.255.255.255:67
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cm := ipv4.ControlMessage{}
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_, err = c.WriteTo(packet, &cm, dstAddr)
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_, err = c.WriteTo(req.ToBytes(), &cm, dstAddr)
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if err != nil {
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return false, wrapErrPrint(err, "Couldn't send a packet to %s", dst)
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}
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@ -113,7 +77,7 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
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// TODO: replicate dhclient's behaviour of retrying several times with progressively bigger timeouts
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b := make([]byte, 1500)
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_ = c.SetReadDeadline(time.Now().Add(defaultDiscoverTime))
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n, _, _, err = c.ReadFrom(b)
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n, _, _, err := c.ReadFrom(b)
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if isTimeout(err) {
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// timed out -- no DHCP servers
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return false, nil
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@ -121,27 +85,24 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
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if err != nil {
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return false, wrapErrPrint(err, "Couldn't receive packet")
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}
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// spew.Dump(n, fromAddr, err, b)
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log.Tracef("Received packet (%v bytes)", n)
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if n < 240 {
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// packet too small for dhcp
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response, err := dhcpv4.FromBytes(b[:n])
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if err != nil {
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log.Debug("DHCPv4: dhcpv4.FromBytes: %s", err)
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continue
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}
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response := dhcp4.Packet(b[:n])
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if response.OpCode() != dhcp4.BootReply ||
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response.HType() != 1 /*Ethernet*/ ||
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response.HLen() > 16 ||
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!bytes.Equal(response.CHAddr(), iface.HardwareAddr) ||
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!bytes.Equal(response.XId(), xID) {
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continue
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}
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log.Debug("DHCPv4: received message from server: %s", response.Summary())
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parsedOptions := response.ParseOptions()
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if t := parsedOptions[dhcp4.OptionDHCPMessageType]; len(t) != 1 {
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continue //packet without DHCP message type
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if !(response.OpCode == dhcpv4.OpcodeBootReply &&
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response.HWType == iana.HWTypeEthernet &&
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bytes.Equal(response.ClientHWAddr, iface.HardwareAddr) &&
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bytes.Equal(response.TransactionID[:], req.TransactionID[:]) &&
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response.Options.Has(dhcpv4.OptionDHCPMessageType)) {
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log.Debug("DHCPv4: received message from server doesn't match our request")
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continue
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}
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log.Tracef("The packet is from an active DHCP server")
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@ -15,9 +15,8 @@ const leaseExpireStatic = 1
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var webHandlersRegistered = false
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// Lease contains the necessary information about a DHCP lease
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// field ordering is important -- yaml fields will mirror ordering from here
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type Lease struct {
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HWAddr net.HardwareAddr `json:"mac" yaml:"hwaddr"`
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HWAddr net.HardwareAddr `json:"mac"`
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IP net.IP `json:"ip"`
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Hostname string `json:"hostname"`
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@ -29,17 +28,17 @@ type Lease struct {
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// ServerConfig - DHCP server configuration
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// field ordering is important -- yaml fields will mirror ordering from here
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type ServerConfig struct {
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Conf4 V4ServerConf `json:"-" yaml:"dhcpv4"`
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Conf6 V6ServerConf `json:"-" yaml:"dhcpv6"`
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Conf4 V4ServerConf `yaml:"dhcpv4"`
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Conf6 V6ServerConf `yaml:"dhcpv6"`
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WorkDir string `json:"-" yaml:"-"`
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DBFilePath string `json:"-" yaml:"-"` // path to DB file
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WorkDir string `yaml:"-"`
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DBFilePath string `yaml:"-"` // path to DB file
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// Called when the configuration is changed by HTTP request
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ConfigModified func() `json:"-" yaml:"-"`
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ConfigModified func() `yaml:"-"`
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// Register an HTTP handler
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HTTPRegister func(string, string, func(http.ResponseWriter, *http.Request)) `json:"-" yaml:"-"`
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HTTPRegister func(string, string, func(http.ResponseWriter, *http.Request)) `yaml:"-"`
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}
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type onLeaseChangedT func(flags int)
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1
go.mod
1
go.mod
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@ -13,7 +13,6 @@ require (
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github.com/insomniacslk/dhcp v0.0.0-20200420235442-ed3125c2efe7
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github.com/joomcode/errorx v1.0.1
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github.com/kardianos/service v1.0.0
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github.com/krolaw/dhcp4 v0.0.0-20180925202202-7cead472c414
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github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7 // indirect
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github.com/mdlayher/raw v0.0.0-20191009151244-50f2db8cc065 // indirect
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github.com/miekg/dns v1.1.29
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2
go.sum
2
go.sum
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@ -74,8 +74,6 @@ github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
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github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
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github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
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github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
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github.com/krolaw/dhcp4 v0.0.0-20180925202202-7cead472c414 h1:6wnYc2S/lVM7BvR32BM74ph7bPgqMztWopMYKgVyEho=
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github.com/krolaw/dhcp4 v0.0.0-20180925202202-7cead472c414/go.mod h1:0AqAH3ZogsCrvrtUpvc6EtVKbc3w6xwZhkvGLuqyi3o=
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github.com/magiconair/properties v1.8.0/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
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github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7 h1:lez6TS6aAau+8wXUP3G9I3TGlmPFEq2CTxBaRqY6AGE=
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github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7/go.mod h1:U6ZQobyTjI/tJyq2HG+i/dfSoFUt8/aZCM+GKtmFk/Y=
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