mirror of
https://github.com/danderson/netboot.git
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121 lines
3.3 KiB
Go
121 lines
3.3 KiB
Go
package dhcp6
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import (
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"bytes"
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"fmt"
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)
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// MessageType contains ID identifying DHCP message type. See RFC 3315
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type MessageType uint8
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// Constants for each of the dhcp message types defined in RFC 3315
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const (
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MsgSolicit MessageType = iota + 1
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MsgAdvertise
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MsgRequest
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MsgConfirm
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MsgRenew
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MsgRebind
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MsgReply
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MsgRelease
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MsgDecline
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MsgReconfigure
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MsgInformationRequest
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MsgRelayForw
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MsgRelayRepl
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)
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// Packet represents a DHCPv6 packet
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type Packet struct {
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Type MessageType
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TransactionID [3]byte
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Options Options
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}
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// Unmarshal creates a Packet out of its serialized representation
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func Unmarshal(bs []byte, packetLength int) (*Packet, error) {
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options, err := UnmarshalOptions(bs[4:packetLength])
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if err != nil {
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return nil, fmt.Errorf("packet has malformed options section: %s", err)
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}
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ret := &Packet{Type: MessageType(bs[0]), Options: options}
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copy(ret.TransactionID[:], bs[1:4])
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return ret, nil
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}
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// Marshal serializes the Packet
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func (p *Packet) Marshal() ([]byte, error) {
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marshalledOptions, err := p.Options.Marshal()
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if err != nil {
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return nil, fmt.Errorf("packet has malformed options section: %s", err)
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}
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ret := make([]byte, len(marshalledOptions)+4, len(marshalledOptions)+4)
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ret[0] = byte(p.Type)
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copy(ret[1:], p.TransactionID[:])
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copy(ret[4:], marshalledOptions)
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return ret, nil
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}
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// ShouldDiscard returns true if the Packet fails validation
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func (p *Packet) ShouldDiscard(serverDuid []byte) error {
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switch p.Type {
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case MsgSolicit:
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return shouldDiscardSolicit(p)
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case MsgRequest:
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return shouldDiscardRequest(p, serverDuid)
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case MsgInformationRequest:
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return shouldDiscardInformationRequest(p, serverDuid)
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case MsgRelease:
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return nil // FIX ME!
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default:
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return fmt.Errorf("Unknown packet")
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}
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}
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func shouldDiscardSolicit(p *Packet) error {
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options := p.Options
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if !options.HasBootFileURLOption() {
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return fmt.Errorf("'Solicit' packet doesn't have file url option")
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}
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if !options.HasClientID() {
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return fmt.Errorf("'Solicit' packet has no Client id option")
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}
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if options.HasServerID() {
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return fmt.Errorf("'Solicit' packet has server id option")
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}
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return nil
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}
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func shouldDiscardRequest(p *Packet, serverDuid []byte) error {
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options := p.Options
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if !options.HasBootFileURLOption() {
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return fmt.Errorf("'Request' packet doesn't have file url option")
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}
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if !options.HasClientID() {
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return fmt.Errorf("'Request' packet has no Client id option")
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}
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if !options.HasServerID() {
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return fmt.Errorf("'Request' packet has no server id option")
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}
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if bytes.Compare(options.ServerID(), serverDuid) != 0 {
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return fmt.Errorf("'Request' packet's server id option (%d) is different from ours (%d)", options.ServerID(), serverDuid)
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}
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return nil
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}
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func shouldDiscardInformationRequest(p *Packet, serverDuid []byte) error {
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options := p.Options
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if !options.HasBootFileURLOption() {
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return fmt.Errorf("'Information-request' packet doesn't have boot file url option")
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}
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if options.HasIaNa() || options.HasIaTa() {
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return fmt.Errorf("'Information-request' packet has an IA option present")
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}
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if options.HasServerID() && (bytes.Compare(options.ServerID(), serverDuid) != 0) {
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return fmt.Errorf("'Information-request' packet's server id option (%d) is different from ours (%d)", options.ServerID(), serverDuid)
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}
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return nil
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}
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