Ejemplo n.º 1
0
/*
 * Create Discover Packet
 */
func (c *Client) DiscoverPacket() dhcp4.Packet {
	messageid := make([]byte, 4)
	if _, err := rand.Read(messageid); err != nil {
		panic(err)
	}

	packet := dhcp4.NewPacket(dhcp4.BootRequest)
	packet.SetCHAddr(c.hardwareAddr)
	packet.SetXId(messageid)
	packet.SetBroadcast(c.broadcast)

	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Discover)})
	//packet.PadToMinSize()
	return packet
}
Ejemplo 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

}
Ejemplo n.º 3
0
/*
 * Create DHCP Decline
 */
func (s *Server) DeclinePacket(requestPacket dhcp4.Packet) dhcp4.Packet {

	declinePacket := dhcp4.NewPacket(dhcp4.BootReply)
	declinePacket.SetXId(requestPacket.XId())
	declinePacket.SetFlags(requestPacket.Flags())

	declinePacket.SetGIAddr(requestPacket.GIAddr())
	declinePacket.SetCHAddr(requestPacket.CHAddr())
	declinePacket.SetSecs(requestPacket.Secs())

	declinePacket.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.NAK)})
	declinePacket.AddOption(dhcp4.OptionSubnetMask, s.subnetMask.To4())
	declinePacket.AddOption(dhcp4.OptionRouter, s.defaultGateway.To4())
	declinePacket.AddOption(dhcp4.OptionDomainNameServer, dhcp4.JoinIPs(s.dnsServers))
	declinePacket.AddOption(dhcp4.OptionServerIdentifier, s.ip.To4())

	return declinePacket
}
Ejemplo n.º 4
0
/*
 * Create Request Packet
 */
func (c *Client) RequestPacket(offerPacket *dhcp4.Packet) dhcp4.Packet {
	offerOptions := offerPacket.ParseOptions()

	packet := dhcp4.NewPacket(dhcp4.BootRequest)
	packet.SetCHAddr(c.hardwareAddr)

	packet.SetXId(offerPacket.XId())
	packet.SetCIAddr(offerPacket.CIAddr())
	packet.SetSIAddr(offerPacket.SIAddr())

	packet.SetBroadcast(c.broadcast)
	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Request)})
	packet.AddOption(dhcp4.OptionRequestedIPAddress, (offerPacket.YIAddr()).To4())
	packet.AddOption(dhcp4.OptionServerIdentifier, offerOptions[dhcp4.OptionServerIdentifier])

	//packet.PadToMinSize()
	return packet
}
Ejemplo n.º 5
0
func TestSetOptions(t *testing.T) {
	id, err := NewID(0, dummyHWAddr)
	assert.NoError(t, err)
	c := &client{
		id: id,
	}
	p := dhcp4.NewPacket(dhcp4.BootRequest)

	var tests = []struct {
		prl []byte
	}{
		{
			prl: []byte{
				byte(dhcp4.OptionSubnetMask),
				byte(dhcp4.OptionRouter),
			},
		},
		{
			prl: []byte{
				byte(dhcp4.OptionSubnetMask),
				byte(dhcp4.OptionRouter),
				byte(dhcp4.OptionNameServer),
			},
		},
	}

	for _, te := range tests {
		c.SetParameterRequestList(te.prl...)
		p, err := c.setOptions(p)
		assert.NoError(t, err)
		assert.NotEmpty(t, p)

		opts := p.ParseOptions()
		prl := opts[dhcp4.OptionParameterRequestList]
		assert.NotNil(t, prl)
		assert.EqualValues(t, te.prl, prl)

		// packet should have client id set
		cid := opts[dhcp4.OptionClientIdentifier]
		assert.NotNil(t, cid)
		b, _ := id.MarshalBinary()
		assert.EqualValues(t, cid, b)
	}
}
Ejemplo n.º 6
0
func DHCPDeclinePacket(hw net.HardwareAddr, ip net.IP, acknowledgement dhcp4.Packet) dhcp4.Packet {
	messageid := make([]byte, 4)
	if _, err := rand.Read(messageid); err != nil {
		panic(err)
	}
	acknowledgementOptions := acknowledgement.ParseOptions()

	packet := dhcp4.NewPacket(dhcp4.BootRequest)
	packet.SetCHAddr(hw)
	packet.SetCIAddr(ip)

	packet.SetXId(messageid)
	packet.SetBroadcast(false)

	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Decline)})
	packet.AddOption(dhcp4.OptionServerIdentifier, acknowledgementOptions[dhcp4.OptionServerIdentifier])

	return packet
}
Ejemplo n.º 7
0
/*
 * Create Release Packet For a Release
 */
func (c *Client) ReleasePacket(acknowledgement *dhcp4.Packet) dhcp4.Packet {
	messageid := make([]byte, 4)
	if _, err := rand.Read(messageid); err != nil {
		panic(err)
	}

	acknowledgementOptions := acknowledgement.ParseOptions()

	packet := dhcp4.NewPacket(dhcp4.BootRequest)
	packet.SetCHAddr(acknowledgement.CHAddr())

	packet.SetXId(messageid)
	packet.SetCIAddr(acknowledgement.YIAddr())

	packet.AddOption(dhcp4.OptionDHCPMessageType, []byte{byte(dhcp4.Release)})
	packet.AddOption(dhcp4.OptionServerIdentifier, acknowledgementOptions[dhcp4.OptionServerIdentifier])

	//packet.PadToMinSize()
	return packet
}