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package main
import (
"log"
"net"
"github.com/insomniacslk/dhcp/dhcpv6"
"github.com/insomniacslk/dhcp/iana"
)
func main() {
// In this example we create and manipulate a DHCPv6 solicit packet
// and encapsulate it in a relay packet. To to this, we use
// `dhcpv6.Message` and `dhcpv6.DHCPv6Relay`, two structures
// that implement the `dhcpv6.DHCPv6` interface.
// Then print the wire-format representation of the packet.
iface, err := net.InterfaceByName("eth0")
if err != nil {
log.Fatal(err)
}
// Create the DHCPv6 Solicit first, using the interface "eth0"
// to get the MAC address
msg, err := dhcpv6.NewSolicit(iface.HardwareAddr)
if err != nil {
log.Fatal(err)
}
// In this example I want to redact the MAC address of my
// network interface, so instead of replacing it manually,
// I will show how to use modifiers for the purpose.
// A Modifier is simply a function that can be applied on
// a DHCPv6 object to manipulate it. Here we use it to
// replace the MAC address with a dummy one.
// Modifiers can be passed to many functions, for example
// to constructors, `Exchange()`, `Solicit()`, etc. Check
// the source code to know where to use them.
// Existing modifiers are implemented in dhcpv6/modifiers.go .
mac, err := net.ParseMAC("00:fa:ce:b0:0c:00")
if err != nil {
log.Fatal(err)
}
duid := dhcpv6.Duid{
Type: dhcpv6.DUID_LLT,
HwType: iana.HWTypeEthernet,
Time: dhcpv6.GetTime(),
LinkLayerAddr: mac,
}
// As suggested above, an alternative is to call
// dhcpv6.NewSolicitForInterface("eth0", dhcpv6.WithClientID(duid))
dhcpv6.WithClientID(duid)(msg)
// Now encapsulate the message in a DHCPv6 relay.
// As per RFC3315, the link-address and peer-address have
// to be set by the relay agent. We use dummy values here.
linkAddr := net.ParseIP("2001:0db8::1")
peerAddr := net.ParseIP("2001:0db8::2")
relay, err := dhcpv6.EncapsulateRelay(msg, dhcpv6.MessageTypeRelayForward, linkAddr, peerAddr)
if err != nil {
log.Fatal(err)
}
// Print a verbose representation of the relay packet, that will also
// show a short representation of the inner Solicit message.
// To print a detailed summary of the inner packet, extract it
// first from the relay using `relay.GetInnerMessage()`.
log.Print(relay.Summary())
// And finally, print the bytes that would be sent on the wire
log.Print(relay.ToBytes())
// Note: there are many more functions in the library, check them
// out in the source code. For example, if you want to decode a
// byte stream into a DHCPv6 message or relay, you can use
// `dhcpv6.FromBytes`.
}
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