Example #1
0
/*
 * Retreive Acknowledgement
 * Wait for the offer for a specific Request Packet.
 */
func (c *Client) GetAcknowledgement(requestPacket *dhcp4.Packet) (dhcp4.Packet, error) {
	for {
		c.connection.SetReadTimeout(c.timeout)
		readBuffer, source, err := c.connection.ReadFrom()
		if err != nil {
			return dhcp4.Packet{}, err
		}

		acknowledgementPacket := dhcp4.Packet(readBuffer)
		acknowledgementPacketOptions := acknowledgementPacket.ParseOptions()

		// Ignore Servers in my Ignore list
		for _, ignoreServer := range c.ignoreServers {
			if source.Equal(ignoreServer) {
				continue
			}

			if acknowledgementPacket.SIAddr().Equal(ignoreServer) {
				continue
			}
		}

		if !bytes.Equal(requestPacket.XId(), acknowledgementPacket.XId()) || len(acknowledgementPacketOptions[dhcp4.OptionDHCPMessageType]) < 1 || (dhcp4.MessageType(acknowledgementPacketOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.ACK && dhcp4.MessageType(acknowledgementPacketOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.NAK) {
			continue
		}

		return acknowledgementPacket, nil
	}
}
Example #2
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
}
Example #3
0
/*
 * Retreive Offer...
 * Wait for the offer for a specific Discovery Packet.
 */
func (c *Client) GetOffer(discoverPacket *dhcp4.Packet) (dhcp4.Packet, error) {
	for {
		c.connection.SetReadTimeout(c.timeout)
		readBuffer, source, err := c.connection.ReadFrom()
		if err != nil {
			return dhcp4.Packet{}, err
		}

		offerPacket := dhcp4.Packet(readBuffer)
		offerPacketOptions := offerPacket.ParseOptions()

		// Ignore Servers in my Ignore list
		for _, ignoreServer := range c.ignoreServers {
			if source.Equal(ignoreServer) {
				continue
			}

			if offerPacket.SIAddr().Equal(ignoreServer) {
				continue
			}
		}

		if len(offerPacketOptions[dhcp4.OptionDHCPMessageType]) < 1 || dhcp4.MessageType(offerPacketOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.Offer || !bytes.Equal(discoverPacket.XId(), offerPacket.XId()) {
			continue
		}

		return offerPacket, nil
	}

}