Beispiel #1
0
// newIAAddr creates a IAAddr for a IANA using the specified IPv6 address,
// and advertises it to a client.
func newIAAddr(ia *dhcp6.IANA, ip net.IP, w dhcp6.ResponseSender, r *dhcp6.Request) error {
	// Send IPv6 address with 60 second preferred lifetime,
	// 90 second valid lifetime, no extra options
	iaaddr, err := dhcp6.NewIAAddr(ip, 60*time.Second, 90*time.Second, nil)
	if err != nil {
		return err
	}

	// Add IAAddr inside IANA, add IANA to options
	_ = ia.Options.Add(dhcp6.OptionIAAddr, iaaddr)
	_ = w.Options().Add(dhcp6.OptionIANA, ia)

	// Advertise address to soliciting clients
	log.Printf("advertising IP: %s", ip)
	_, err = w.Send(dhcp6.MessageTypeAdvertise)
	return err
}
Beispiel #2
0
// handle is a handler which assigns IPv6 addresses using DHCPv6.
func handle(ip net.IP, w dhcp6.ResponseSender, r *dhcp6.Request) error {
	// Accept only Solicit, Request, or Confirm, since this server
	// does not handle Information Request or other message types
	valid := map[dhcp6.MessageType]struct{}{
		dhcp6.MessageTypeSolicit: struct{}{},
		dhcp6.MessageTypeRequest: struct{}{},
		dhcp6.MessageTypeConfirm: struct{}{},
	}
	if _, ok := valid[r.MessageType]; !ok {
		return nil
	}

	// Make sure client sent a client ID
	duid, ok := r.Options.Get(dhcp6.OptionClientID)
	if !ok {
		return nil
	}

	// Log information about the incoming request.
	log.Printf("[%s] id: %s, type: %d, len: %d, tx: %s",
		hex.EncodeToString(duid),
		r.RemoteAddr,
		r.MessageType,
		r.Length,
		hex.EncodeToString(r.TransactionID[:]),
	)

	// Print out options the client has requested
	if opts, ok, err := r.Options.OptionRequest(); err == nil && ok {
		log.Println("\t- requested:")
		for _, o := range opts {
			log.Printf("\t\t - %s", o)
		}
	}

	// Client must send a IANA to retrieve an IPv6 address
	ianas, ok, err := r.Options.IANA()
	if err != nil {
		return err
	}
	if !ok {
		log.Println("no IANAs provided")
		return nil
	}

	// Only accept one IANA
	if len(ianas) > 1 {
		log.Println("can only handle one IANA")
		return nil
	}
	ia := ianas[0]

	log.Printf("\tIANA: %s (%s, %s), opts: %v",
		hex.EncodeToString(ia.IAID[:]),
		ia.T1,
		ia.T2,
		ia.Options,
	)

	// Instruct client to prefer this server unconditionally
	_ = w.Options().Add(dhcp6.OptionPreference, dhcp6.Preference(255))

	// IANA may already have an IAAddr if an address was already assigned.
	// If not, assign a new one.
	iaaddrs, ok, err := ia.Options.IAAddr()
	if err != nil {
		return err
	}

	// Client did not indicate a previous address, and is soliciting.
	// Advertise a new IPv6 address.
	if !ok && r.MessageType == dhcp6.MessageTypeSolicit {
		return newIAAddr(ia, ip, w, r)
	} else if !ok {
		// Client did not indicate an address and is not soliciting.  Ignore.
		return nil
	}

	// Confirm or renew an existing IPv6 address

	// Must have an IAAddr, but we ignore if more than one is present
	if len(iaaddrs) == 0 {
		return nil
	}
	iaa := iaaddrs[0]

	log.Printf("\t\tIAAddr: %s (%s, %s), opts: %v",
		iaa.IP,
		iaa.PreferredLifetime,
		iaa.ValidLifetime,
		iaa.Options,
	)

	// Add IAAddr inside IANA, add IANA to options
	_ = ia.Options.Add(dhcp6.OptionIAAddr, iaa)
	_ = w.Options().Add(dhcp6.OptionIANA, ia)

	// Send reply to client
	_, err = w.Send(dhcp6.MessageTypeReply)
	return err
}
Beispiel #3
0
// solicit is a function which can be adapted as a HandlerFunc.
func solicit(w dhcp6.ResponseSender, r *dhcp6.Request) {
	w.Send(dhcp6.MessageTypeAdvertise)
}