func (c *client) Renew(id ID, ack *dhcp.Packet) (*dhcp.Packet, error) {
c.Lock()
defer c.Unlock()
log.Debugf("renewing IP %s", ack.YourIP())
cl, err := c.newClient(ack)
if err != nil {
return nil, err
}
defer cl.Close()
p := dhcp4.Packet(ack.Packet)
var newack dhcp4.Packet
err = withRetry(func() error {
var err error
newack, err = c.renew(id, p, cl)
return err
})
if err != nil {
return nil, err
}
return dhcp.NewPacket([]byte(newack)), nil
}
func (c *client) request(id ID, cl *dhcp4client.Client) (bool, *dhcp.Packet, error) {
dp, err := c.discoverPacket(id, cl)
if err != nil {
return false, nil, err
}
dp.PadToMinSize()
if err = cl.SendPacket(*dp); err != nil {
return false, nil, err
}
var op dhcp4.Packet
for {
op, err = cl.GetOffer(dp)
if err != nil {
return false, nil, err
}
if isCompletePacket(dhcp.NewPacket([]byte(op))) {
break
}
}
rp, err := c.requestPacket(id, cl, &op)
if err != nil {
return false, nil, err
}
rp.PadToMinSize()
if err = cl.SendPacket(*rp); err != nil {
return false, nil, err
}
ack, err := cl.GetAcknowledgement(rp)
if err != nil {
return false, nil, err
}
opts := ack.ParseOptions()
if dhcp4.MessageType(opts[dhcp4.OptionDHCPMessageType][0]) == dhcp4.NAK {
return false, nil, fmt.Errorf("Got NAK from DHCP server")
}
return true, dhcp.NewPacket([]byte(ack)), nil
}
func (c *client) LastAck() *dhcp.Packet {
defer trace.End(trace.Begin(""))
if c.ack == nil {
return nil
}
return dhcp.NewPacket(c.ack)
}
func (c *client) newClient() (*dhcp4client.Client, error) {
defer trace.End(trace.Begin(""))
ack := dhcp.NewPacket(c.ack)
conn, err := dhcp4client.NewInetSock(dhcp4client.SetRemoteAddr(net.UDPAddr{IP: ack.ServerIP(), Port: 67}))
if err != nil {
return nil, err
}
cl, err := dhcp4client.New(dhcp4client.Connection(conn), dhcp4client.Timeout(c.timeout))
if err != nil {
return nil, err
}
return cl, nil
}