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
|
package dhcpv4
import (
"fmt"
"net"
"strings"
"github.com/u-root/u-root/pkg/uio"
)
// This option implements the router option
// https://tools.ietf.org/html/rfc2132
// OptRouter represents an option encapsulating the routers.
type OptRouter struct {
Routers []net.IP
}
// ParseIPs parses an IPv4 address from a DHCP packet as used and specified by
// options in RFC 2132, Sections 3.5 through 3.13, 8.2, 8.3, 8.5, 8.6, 8.9, and
// 8.10.
func ParseIPs(data []byte) ([]net.IP, error) {
buf := uio.NewBigEndianBuffer(data)
if buf.Len() == 0 {
return nil, fmt.Errorf("IP DHCP options must always list at least one IP")
}
ips := make([]net.IP, 0, buf.Len()/net.IPv4len)
for buf.Has(net.IPv4len) {
ips = append(ips, net.IP(buf.CopyN(net.IPv4len)))
}
return ips, buf.FinError()
}
// IPsToBytes marshals an IPv4 address to a DHCP packet as specified by RFC
// 2132, Section 3.5 et al.
func IPsToBytes(i []net.IP) []byte {
buf := uio.NewBigEndianBuffer(nil)
for _, ip := range i {
buf.WriteBytes(ip.To4())
}
return buf.Data()
}
// IPsToString returns a human-readable representation of a list of IPs.
func IPsToString(i []net.IP) string {
s := make([]string, 0, len(i))
for _, ip := range i {
s = append(s, ip.String())
}
return strings.Join(s, ", ")
}
// ParseOptRouter returns a new OptRouter from a byte stream, or error if any.
func ParseOptRouter(data []byte) (*OptRouter, error) {
ips, err := ParseIPs(data)
if err != nil {
return nil, err
}
return &OptRouter{Routers: ips}, nil
}
// Code returns the option code.
func (o *OptRouter) Code() OptionCode {
return OptionRouter
}
// ToBytes returns a serialized stream of bytes for this option.
func (o *OptRouter) ToBytes() []byte {
return IPsToBytes(o.Routers)
}
// String returns a human-readable string.
func (o *OptRouter) String() string {
return fmt.Sprintf("Routers -> %s", IPsToString(o.Routers))
}
|
