1 package linux
2
3 import (
4 "fmt"
5 "net"
6 "os"
7 "strings"
8 )
9
10 const (
11 chatty_myip = false
12 )
13
14 var (
15 pref_nic_if = []string{"dummy", "wg", "tun"}
16 )
17
18 func fail(txt string, err error) {
19 if err == nil {
20 return
21 }
22 fmt.Printf("ERROR: %s: %s\n", txt, err)
23 os.Exit(10)
24 }
25
26
27 func (*linux) MyIP() string {
28 ifaces, err := net.Interfaces()
29 fail("could not get interfaces", err)
30 var cur_ip *net.IPNet
31 cur_pref := 0
32
33 for _, iface := range ifaces {
34 if chatty_myip {
35 fmt.Printf("Iface %s:\n", iface.Name)
36 }
37 addrs, err := iface.Addrs()
38 fail("cannot get interface address", err)
39 for _, adr := range addrs {
40 use := true
41 ipnet, ok := adr.(*net.IPNet)
42 if !ok {
43 continue
44 }
45 s := ""
46 if ipnet.IP.IsLoopback() {
47 use = false
48 s = " [loopback]"
49 }
50 if ipnet.IP.To4() == nil {
51 use = false
52 s = " [not ip4]"
53 }
54 if chatty_myip {
55 fmt.Printf(" %s%s\n", adr.String(), s)
56 }
57 if use {
58 if cur_ip == nil || nic_name_pref(iface.Name) > cur_pref {
59 cur_ip = ipnet
60 }
61 }
62 }
63 }
64 if cur_ip != nil {
65 return cur_ip.IP.String()
66 }
67 return ""
68 }
69
70 func nic_name_pref(name string) int {
71 for i, n := range pref_nic_if {
72 if strings.HasPrefix(name, n) {
73 return i + 1
74 }
75 }
76 return len(pref_nic_if) + 2
77 }
78
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