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
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
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
}
|
