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dnsinfo.go
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dnsinfo.go
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//go:build !windows
// +build !windows
package vpnlib
import (
"bufio"
"fmt"
"net"
"os"
"os/exec"
"runtime"
"strings"
)
// GetDnsServers returns a list of all active resolvers used by the system
func GetDnsServers() ([]string, error) {
switch runtime.GOOS {
case "darwin":
return getDnsDarwin()
case "linux":
return getDnsLinux()
default:
return nil, fmt.Errorf("runtime %s not supported", runtime.GOOS)
}
}
func getDnsDarwin() ([]string, error) {
out, err := exec.Command("scutil", "--dns").Output()
if err != nil {
return nil, fmt.Errorf("error getting DNS servers: %v", err)
}
var servers []string
for _, line := range strings.Split(string(out), "\n") {
if strings.Contains(line, "nameserver") {
ip := strings.TrimSpace(strings.Split(line, ":")[1])
if net.ParseIP(ip) != nil {
servers = append(servers, ip)
}
}
}
return servers, nil
}
func getDnsLinux() ([]string, error) {
file, err := os.Open("/etc/resolv.conf")
if err != nil {
return nil, fmt.Errorf("error getting DNS servers: %v", err)
}
defer file.Close()
var servers []string
scanner := bufio.NewScanner(file)
for scanner.Scan() {
line := scanner.Text()
if strings.HasPrefix(line, "nameserver") {
ip := strings.TrimSpace(strings.Split(line, " ")[1])
if net.ParseIP(ip) != nil {
servers = append(servers, ip)
}
}
}
return servers, nil
}