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|
package dhcpv6
import (
"errors"
"fmt"
"net"
)
const RelayHeaderSize = 34
type DHCPv6Relay struct {
messageType MessageType
hopCount uint8
linkAddr net.IP
peerAddr net.IP
options []Option
}
func (r *DHCPv6Relay) Type() MessageType {
return r.messageType
}
func (r *DHCPv6Relay) MessageTypeToString() string {
return MessageTypeToString(r.messageType)
}
func (r *DHCPv6Relay) String() string {
ret := fmt.Sprintf(
"DHCPv6Relay(messageType=%v hopcount=%v, linkaddr=%v, peeraddr=%v, %d options)",
r.MessageTypeToString(), r.hopCount, r.linkAddr, r.peerAddr, len(r.options),
)
return ret
}
func (r *DHCPv6Relay) Summary() string {
ret := fmt.Sprintf(
"DHCPv6Relay\n"+
" messageType=%v\n"+
" hopcount=%v\n"+
" linkaddr=%v\n"+
" peeraddr=%v\n"+
" options=%v\n",
r.MessageTypeToString(),
r.hopCount,
r.linkAddr,
r.peerAddr,
r.options,
)
return ret
}
func (r *DHCPv6Relay) ToBytes() []byte {
ret := make([]byte, RelayHeaderSize)
ret[0] = byte(r.messageType)
ret[1] = byte(r.hopCount)
copy(ret[2:18], r.linkAddr)
copy(ret[18:34], r.peerAddr)
for _, opt := range r.options {
ret = append(ret, opt.ToBytes()...)
}
return ret
}
func (r *DHCPv6Relay) MessageType() MessageType {
return r.messageType
}
func (r *DHCPv6Relay) SetMessageType(messageType MessageType) {
// not enforcing if message type is not a RELAY_FORW or a RELAY_REPL message
r.messageType = messageType
}
func (r *DHCPv6Relay) HopCount() uint8 {
return r.hopCount
}
func (r *DHCPv6Relay) SetHopCount(hopCount uint8) {
r.hopCount = hopCount
}
func (r *DHCPv6Relay) LinkAddr() net.IP {
return r.linkAddr
}
func (r *DHCPv6Relay) SetLinkAddr(linkAddr net.IP) {
r.linkAddr = linkAddr
}
func (r *DHCPv6Relay) PeerAddr() net.IP {
return r.peerAddr
}
func (r *DHCPv6Relay) SetPeerAddr(peerAddr net.IP) {
r.peerAddr = peerAddr
}
func (r *DHCPv6Relay) Length() int {
mLen := RelayHeaderSize
for _, opt := range r.options {
mLen += opt.Length() + 4 // +4 for opt code and opt len
}
return mLen
}
func (r *DHCPv6Relay) Options() []Option {
return r.options
}
func (r *DHCPv6Relay) GetOption(code OptionCode) []Option {
return getOptions(r.options, code, false)
}
func (r *DHCPv6Relay) GetOneOption(code OptionCode) Option {
return getOption(r.options, code)
}
func (r *DHCPv6Relay) SetOptions(options []Option) {
r.options = options
}
func (r *DHCPv6Relay) AddOption(option Option) {
r.options = append(r.options, option)
}
// UpdateOption replaces the first option of the same type as the specified one.
func (r *DHCPv6Relay) UpdateOption(option Option) {
for idx, opt := range r.options {
if opt.Code() == option.Code() {
r.options[idx] = option
// don't look further
return
}
}
// if not found, add it
r.AddOption(option)
}
func (r *DHCPv6Relay) IsRelay() bool {
return true
}
// Recurse into a relay message and extract and return the inner DHCPv6Message.
// Return nil if none found (e.g. not a relay message).
func (d *DHCPv6Relay) GetInnerMessage() (DHCPv6, error) {
var (
p DHCPv6
err error
)
p = d
for {
if !p.IsRelay() {
return p, nil
}
p, err = DecapsulateRelay(p)
if err != nil {
return nil, err
}
}
}
// GetInnerPeerAddr returns the peer address in the inner most relay info
// header, this is typically the IP address of the client making the request.
func (r *DHCPv6Relay) GetInnerPeerAddr() (net.IP, error) {
var (
p DHCPv6
err error
)
p = r
hops := r.HopCount()
addr := r.PeerAddr()
for i := uint8(0); i < hops; i++ {
p, err = DecapsulateRelay(p)
if err != nil {
return nil, err
}
if p.IsRelay() {
addr = p.(*DHCPv6Relay).PeerAddr()
} else {
return nil, fmt.Errorf("Wrong Hop count")
}
}
return addr, nil
}
// NewRelayReplFromRelayForw creates a RELAY_REPL packet based on a RELAY_FORW
// packet and replaces the inner message with the passed DHCPv6 message.
func NewRelayReplFromRelayForw(relayForw, msg DHCPv6) (DHCPv6, error) {
var (
err error
linkAddr, peerAddr []net.IP
optiids []Option
)
if relayForw == nil {
return nil, errors.New("RELAY_FORW cannot be nil")
}
relay, ok := relayForw.(*DHCPv6Relay)
if !ok {
return nil, errors.New("Not a DHCPv6Relay")
}
if relay.Type() != RELAY_FORW {
return nil, errors.New("The passed packet is not of type RELAY_FORW")
}
if msg == nil {
return nil, errors.New("The passed message cannot be nil")
}
if msg.IsRelay() {
return nil, errors.New("The passed message cannot be a relay")
}
for {
linkAddr = append(linkAddr, relay.LinkAddr())
peerAddr = append(peerAddr, relay.PeerAddr())
optiids = append(optiids, relay.GetOneOption(OPTION_INTERFACE_ID))
decap, err := DecapsulateRelay(relay)
if err != nil {
return nil, err
}
if decap.IsRelay() {
relay = decap.(*DHCPv6Relay)
} else {
break
}
}
for i := len(linkAddr) - 1; i >= 0; i-- {
msg, err = EncapsulateRelay(msg, RELAY_REPL, linkAddr[i], peerAddr[i])
if opt := optiids[i]; opt != nil {
msg.AddOption(opt)
}
if err != nil {
return nil, err
}
}
return msg, nil
}
|
