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
|
// Copyright 2021 CNI authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"github.com/d2g/dhcp4"
"github.com/d2g/dhcp4client"
)
const (
MaxDHCPLen = 576
)
//Send the Discovery Packet to the Broadcast Channel
func DhcpSendDiscoverPacket(c *dhcp4client.Client, options dhcp4.Options) (dhcp4.Packet, error) {
discoveryPacket := c.DiscoverPacket()
for opt, data := range options {
discoveryPacket.AddOption(opt, data)
}
discoveryPacket.PadToMinSize()
return discoveryPacket, c.SendPacket(discoveryPacket)
}
//Send Request Based On the offer Received.
func DhcpSendRequest(c *dhcp4client.Client, options dhcp4.Options, offerPacket *dhcp4.Packet) (dhcp4.Packet, error) {
requestPacket := c.RequestPacket(offerPacket)
for opt, data := range options {
requestPacket.AddOption(opt, data)
}
requestPacket.PadToMinSize()
return requestPacket, c.SendPacket(requestPacket)
}
//Send Decline to the received acknowledgement.
func DhcpSendDecline(c *dhcp4client.Client, acknowledgementPacket *dhcp4.Packet, options dhcp4.Options) (dhcp4.Packet, error) {
declinePacket := c.DeclinePacket(acknowledgementPacket)
for opt, data := range options {
declinePacket.AddOption(opt, data)
}
declinePacket.PadToMinSize()
return declinePacket, c.SendPacket(declinePacket)
}
//Lets do a Full DHCP Request.
func DhcpRequest(c *dhcp4client.Client, options dhcp4.Options) (bool, dhcp4.Packet, error) {
discoveryPacket, err := DhcpSendDiscoverPacket(c, options)
if err != nil {
return false, discoveryPacket, err
}
offerPacket, err := c.GetOffer(&discoveryPacket)
if err != nil {
return false, offerPacket, err
}
requestPacket, err := DhcpSendRequest(c, options, &offerPacket)
if err != nil {
return false, requestPacket, err
}
acknowledgement, err := c.GetAcknowledgement(&requestPacket)
if err != nil {
return false, acknowledgement, err
}
acknowledgementOptions := acknowledgement.ParseOptions()
if dhcp4.MessageType(acknowledgementOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.ACK {
return false, acknowledgement, nil
}
return true, acknowledgement, nil
}
//Renew a lease backed on the Acknowledgement Packet.
//Returns Successful, The AcknoledgementPacket, Any Errors
func DhcpRenew(c *dhcp4client.Client, acknowledgement dhcp4.Packet, options dhcp4.Options) (bool, dhcp4.Packet, error) {
renewRequest := c.RenewalRequestPacket(&acknowledgement)
for opt, data := range options {
renewRequest.AddOption(opt, data)
}
renewRequest.PadToMinSize()
err := c.SendPacket(renewRequest)
if err != nil {
return false, renewRequest, err
}
newAcknowledgement, err := c.GetAcknowledgement(&renewRequest)
if err != nil {
return false, newAcknowledgement, err
}
newAcknowledgementOptions := newAcknowledgement.ParseOptions()
if dhcp4.MessageType(newAcknowledgementOptions[dhcp4.OptionDHCPMessageType][0]) != dhcp4.ACK {
return false, newAcknowledgement, nil
}
return true, newAcknowledgement, nil
}
//Release a lease backed on the Acknowledgement Packet.
//Returns Any Errors
func DhcpRelease(c *dhcp4client.Client, acknowledgement dhcp4.Packet, options dhcp4.Options) error {
release := c.ReleasePacket(&acknowledgement)
for opt, data := range options {
release.AddOption(opt, data)
}
release.PadToMinSize()
return c.SendPacket(release)
}
|
