add all files from Hong

plugins/serverid/plugin.go

@@ -0,0 +1,155 @@
+// Copyright 2018-present the CoreDHCP Authors. All rights reserved
+// This source code is licensed under the MIT license found in the
+// LICENSE file in the root directory of this source tree.
+
+package serverid
+
+import (
+	"errors"
+	"net"
+	"strings"
+
+	"github.com/coredhcp/coredhcp/handler"
+	"github.com/coredhcp/coredhcp/logger"
+	"github.com/coredhcp/coredhcp/plugins"
+	"github.com/insomniacslk/dhcp/dhcpv4"
+	"github.com/insomniacslk/dhcp/dhcpv6"
+	"github.com/insomniacslk/dhcp/iana"
+)
+
+var log = logger.GetLogger("plugins/server_id")
+
+// Plugin wraps plugin registration information
+var Plugin = plugins.Plugin{
+	Name:   "server_id",
+	Setup6: setup6,
+	Setup4: setup4,
+}
+
+// v6ServerID is the DUID of the v6 server
+var (
+	v6ServerID dhcpv6.DUID
+	v4ServerID net.IP
+)
+
+// Handler6 handles DHCPv6 packets for the server_id plugin.
+func Handler6(req, resp dhcpv6.DHCPv6) (dhcpv6.DHCPv6, bool) {
+	if v6ServerID == nil {
+		log.Fatal("BUG: Plugin is running uninitialized!")
+		return nil, true
+	}
+
+	msg, err := req.GetInnerMessage()
+	if err != nil {
+		// BUG: this should already have failed in the main handler. Abort
+		log.Error(err)
+		return nil, true
+	}
+
+	if sid := msg.Options.ServerID(); sid != nil {
+		// RFC8415 §16.{2,5,7}
+		// These message types MUST be discarded if they contain *any* ServerID option
+		if msg.MessageType == dhcpv6.MessageTypeSolicit ||
+			msg.MessageType == dhcpv6.MessageTypeConfirm ||
+			msg.MessageType == dhcpv6.MessageTypeRebind {
+			return nil, true
+		}
+
+		// Approximately all others MUST be discarded if the ServerID doesn't match
+		if !sid.Equal(v6ServerID) {
+			log.Infof("requested server ID does not match this server's ID. Got %v, want %v", sid, v6ServerID)
+			return nil, true
+		}
+	} else if msg.MessageType == dhcpv6.MessageTypeRequest ||
+		msg.MessageType == dhcpv6.MessageTypeRenew ||
+		msg.MessageType == dhcpv6.MessageTypeDecline ||
+		msg.MessageType == dhcpv6.MessageTypeRelease {
+		// RFC8415 §16.{6,8,10,11}
+		// These message types MUST be discarded if they *don't* contain a ServerID option
+		return nil, true
+	}
+	dhcpv6.WithServerID(v6ServerID)(resp)
+	return resp, false
+}
+
+// Handler4 handles DHCPv4 packets for the server_id plugin.
+func Handler4(req, resp *dhcpv4.DHCPv4) (*dhcpv4.DHCPv4, bool) {
+	if v4ServerID == nil {
+		log.Fatal("BUG: Plugin is running uninitialized!")
+		return nil, true
+	}
+	if req.OpCode != dhcpv4.OpcodeBootRequest {
+		log.Warningf("not a BootRequest, ignoring")
+		return resp, false
+	}
+	if req.ServerIPAddr != nil &&
+		!req.ServerIPAddr.Equal(net.IPv4zero) &&
+		!req.ServerIPAddr.Equal(v4ServerID) {
+		// This request is not for us, drop it.
+		log.Infof("requested server ID does not match this server's ID. Got %v, want %v", req.ServerIPAddr, v4ServerID)
+		return nil, true
+	}
+	resp.ServerIPAddr = make(net.IP, net.IPv4len)
+	copy(resp.ServerIPAddr[:], v4ServerID)
+	resp.UpdateOption(dhcpv4.OptServerIdentifier(v4ServerID))
+	return resp, false
+}
+
+func setup4(args ...string) (handler.Handler4, error) {
+	log.Printf("loading `server_id` plugin for DHCPv4 with args: %v", args)
+	if len(args) < 1 {
+		return nil, errors.New("need an argument")
+	}
+	serverID := net.ParseIP(args[0])
+	if serverID == nil {
+		return nil, errors.New("invalid or empty IP address")
+	}
+	if serverID.To4() == nil {
+		return nil, errors.New("not a valid IPv4 address")
+	}
+	v4ServerID = serverID.To4()
+	return Handler4, nil
+}
+
+func setup6(args ...string) (handler.Handler6, error) {
+	log.Printf("loading `server_id` plugin for DHCPv6 with args: %v", args)
+	if len(args) < 2 {
+		return nil, errors.New("need a DUID type and value")
+	}
+	duidType := args[0]
+	if duidType == "" {
+		return nil, errors.New("got empty DUID type")
+	}
+	duidValue := args[1]
+	if duidValue == "" {
+		return nil, errors.New("got empty DUID value")
+	}
+	duidType = strings.ToLower(duidType)
+	hwaddr, err := net.ParseMAC(duidValue)
+	if err != nil {
+		return nil, err
+	}
+	switch duidType {
+	case "ll", "duid-ll", "duid_ll":
+		v6ServerID = &dhcpv6.DUIDLL{
+			// sorry, only ethernet for now
+			HWType:        iana.HWTypeEthernet,
+			LinkLayerAddr: hwaddr,
+		}
+	case "llt", "duid-llt", "duid_llt":
+		v6ServerID = &dhcpv6.DUIDLLT{
+			// sorry, zero-time for now
+			Time: 0,
+			// sorry, only ethernet for now
+			HWType:        iana.HWTypeEthernet,
+			LinkLayerAddr: hwaddr,
+		}
+	case "en", "uuid":
+		return nil, errors.New("EN/UUID DUID type not supported yet")
+	default:
+		return nil, errors.New("Opaque DUID type not supported yet")
+	}
+	log.Printf("using %s %s", duidType, duidValue)
+
+	return Handler6, nil
+}