/*
* 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
}
}
/*
* 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
}
/*
* 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
}
}