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
|
package arping
import (
"errors"
"fmt"
"net"
)
func findIPInNetworkFromIface(dstIP net.IP, iface net.Interface) (net.IP, error) {
addrs, err := iface.Addrs()
if err != nil {
return nil, err
}
for _, a := range addrs {
if ipnet, ok := a.(*net.IPNet); ok {
if ipnet.Contains(dstIP) {
return ipnet.IP, nil
}
}
}
return nil, fmt.Errorf("iface: '%s' can't reach ip: '%s'", iface.Name, dstIP)
}
func findUsableInterfaceForNetwork(dstIP net.IP) (*net.Interface, error) {
ifaces, err := net.Interfaces()
if err != nil {
return nil, err
}
isDown := func(iface net.Interface) bool {
return iface.Flags&1 == 0
}
hasAddressInNetwork := func(iface net.Interface) bool {
if _, err := findIPInNetworkFromIface(dstIP, iface); err != nil {
return false
}
return true
}
verboseLog.Println("search usable interface")
logIfaceResult := func(msg string, iface net.Interface) {
verboseLog.Printf("%10s: %6s %18s %s", msg, iface.Name, iface.HardwareAddr, iface.Flags)
}
for _, iface := range ifaces {
if isDown(iface) {
logIfaceResult("DOWN", iface)
continue
}
if !hasAddressInNetwork(iface) {
logIfaceResult("OTHER NET", iface)
continue
}
logIfaceResult("USABLE", iface)
return &iface, nil
}
return nil, errors.New("no usable interface found")
}
|
