Exemplo n.º 1
0
Arquivo: client.go Projeto: vmware/vic
func (c *client) isCompletePacket(p *dhcp.Packet) bool {
	complete := !ip.IsUnspecifiedIP(p.YourIP()) &&
		!ip.IsUnspecifiedIP(p.ServerIP())

	if !complete {
		return false
	}

	for _, param := range c.params {
		switch dhcp4.OptionCode(param) {
		case dhcp4.OptionSubnetMask:
			ones, bits := p.SubnetMask().Size()
			if ones == 0 || bits == 0 {
				return false
			}
		case dhcp4.OptionRouter:
			if ip.IsUnspecifiedIP(p.Gateway()) {
				return false
			}
		case dhcp4.OptionDomainNameServer:
			if len(p.DNS()) == 0 {
				return false
			}
		}
	}

	if p.LeaseTime().Seconds() == 0 {
		return false
	}

	return true
}
Exemplo n.º 2
0
/*
 * Create DHCP Offer Packet
 */
func (s *Server) OfferPacket(discoverPacket dhcp4.Packet) dhcp4.Packet {

	offerPacket := dhcp4.NewPacket(dhcp4.BootReply)
	offerPacket.SetXId(discoverPacket.XId())
	offerPacket.SetFlags(discoverPacket.Flags())

	offerPacket.SetCHAddr(discoverPacket.CHAddr())
	offerPacket.SetGIAddr(discoverPacket.GIAddr())
	offerPacket.SetSecs(discoverPacket.Secs())

	//53
	offerPacket.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Offer)})
	//54
	offerPacket.AddOption(dhcp4.OptionServerIdentifier, s.ip.To4())
	//51
	offerPacket.AddOption(dhcp4.OptionIPAddressLeaseTime, dhcp4.OptionsLeaseTime(s.leaseDuration))

	//Other options go in requested order...
	discoverPacketOptions := discoverPacket.ParseOptions()

	ourOptions := make(dhcp4.Options)

	//1
	ourOptions[dhcp4.OptionSubnetMask] = s.subnetMask.To4()
	//3
	ourOptions[dhcp4.OptionRouter] = s.defaultGateway.To4()
	//6
	ourOptions[dhcp4.OptionDomainNameServer] = dhcp4.JoinIPs(s.dnsServers)

	if discoverPacketOptions[dhcp4.OptionParameterRequestList] != nil {
		//Loop through the requested options and if we have them add them.
		for _, optionCode := range discoverPacketOptions[dhcp4.OptionParameterRequestList] {
			if !bytes.Equal(ourOptions[dhcp4.OptionCode(optionCode)], []byte{}) {
				offerPacket.AddOption(dhcp4.OptionCode(optionCode), ourOptions[dhcp4.OptionCode(optionCode)])
				delete(ourOptions, dhcp4.OptionCode(optionCode))
			}
		}
	}

	//Add all the options not requested.
	for optionCode, optionValue := range ourOptions {
		offerPacket.AddOption(optionCode, optionValue)
	}

	return offerPacket

}
Exemplo n.º 3
0
func GetOffer() (ip net.IP, subnet net.IPNet, err error) {
	ip = nil
	subnet.IP = nil
	subnet.Mask = nil

	// Generate a random mac address for this request
	hwaddr, e := GenerateMacAddr()
	if e != nil {
		err = e
		return
	}

	// Setup DHCP socket
	//socket, e := dhcp4client.NewInetSock(local_addr, remote_addr)
	socket, e := dhcp4client.NewInetSock()
	if e != nil {
		err = e
		return
	}

	// Setup DHCP client
	client, e := dhcp4client.New(
		dhcp4client.HardwareAddr(hwaddr),
		dhcp4client.Connection(socket),
	)

	// Send a DHCPREQUEST
	result, packet, e := client.Request()

	if !result {
		msg := fmt.Sprintf("DHCPREQUEST failed: %v", e)
		err = errors.New(msg)
		return
	}

	if e != nil {
		networkError, ok := e.(*net.OpError)
		if ok && networkError.Timeout() {
			msg := fmt.Sprintf("Cannot find DHCP server: %v", networkError)
			err = errors.New(msg)
		} else {
			msg := fmt.Sprintf("DHCPREQUEST failed: %v", networkError)
			err = errors.New(msg)
		}
		return
	}

	// Determine the netmask of the network
	options := packet.ParseOptions()
	mask := make(net.IPMask, net.IPv4len)
	mask = options[dhcp4.OptionCode(dhcp4.OptionSubnetMask)]

	// Setup the return structures
	ip = packet.YIAddr()
	subnet.IP = ip.To4().Mask(mask)
	subnet.Mask = mask

	return
}