1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
|
package dhcp6opts
import (
"io"
"net"
"github.com/mdlayher/dhcp6"
"github.com/mdlayher/dhcp6/internal/buffer"
)
// RelayMessage represents a raw RelayMessage generated by DHCPv6 relay agent, using RFC 3315,
// Section 7.
type RelayMessage struct {
// RELAY-FORW or RELAY-REPL only
MessageType dhcp6.MessageType
// Number of relay agents that have relayed this
// message.
HopCount uint8
// A global or site-local address that will be used by
// the server to identify the link on which the client
// is located.
LinkAddress net.IP
// The address of the client or relay agent from which
// the message to be relayed was received.
PeerAddress net.IP
// Options specifies a map of DHCP options. Its methods can be used to
// retrieve data from an incoming RelayMessage, or send data with an outgoing
// RelayMessage.
// MUST include a "Relay Message option" (see
// section 22.10); MAY include other options added by
// the relay agent.
Options dhcp6.Options
}
// MarshalBinary allocates a byte slice containing the data
// from a RelayMessage.
func (rm *RelayMessage) MarshalBinary() ([]byte, error) {
// 1 byte: message type
// 1 byte: hop-count
// 16 bytes: link-address
// 16 bytes: peer-address
// N bytes: options slice byte count
b := buffer.New(nil)
b.Write8(uint8(rm.MessageType))
b.Write8(rm.HopCount)
copy(b.WriteN(net.IPv6len), rm.LinkAddress)
copy(b.WriteN(net.IPv6len), rm.PeerAddress)
opts, err := rm.Options.MarshalBinary()
if err != nil {
return nil, err
}
b.WriteBytes(opts)
return b.Data(), nil
}
// UnmarshalBinary unmarshals a raw byte slice into a RelayMessage.
//
// If the byte slice does not contain enough data to form a valid RelayMessage,
// ErrInvalidPacket is returned.
func (rm *RelayMessage) UnmarshalBinary(p []byte) error {
b := buffer.New(p)
// RelayMessage must contain at least message type, hop-count, link-address and peer-address
if b.Len() < 34 {
return io.ErrUnexpectedEOF
}
rm.MessageType = dhcp6.MessageType(b.Read8())
rm.HopCount = b.Read8()
rm.LinkAddress = make(net.IP, net.IPv6len)
copy(rm.LinkAddress, b.Consume(net.IPv6len))
rm.PeerAddress = make(net.IP, net.IPv6len)
copy(rm.PeerAddress, b.Consume(net.IPv6len))
if err := (&rm.Options).UnmarshalBinary(b.Remaining()); err != nil {
// Invalid options means an invalid RelayMessage
return dhcp6.ErrInvalidPacket
}
return nil
}
|
