removing legacy DNS logic

This commit is contained in:
afeiszli 2022-05-23 10:02:47 -04:00 committed by 0xdcarns
parent 3f038ab951
commit ccd5243f47
2 changed files with 2 additions and 153 deletions

View file

@ -1,149 +0,0 @@
package local
import (
"fmt"
"net"
"os"
"strings"
"time"
//"github.com/davecgh/go-spew/spew"
"log"
"os/exec"
"github.com/gravitl/netmaker/logger"
"github.com/gravitl/netmaker/models"
"github.com/gravitl/netmaker/netclient/ncutils"
)
const DNS_UNREACHABLE_ERROR = "nameserver unreachable"
// SetDNSWithRetry - Attempt setting dns, if it fails return true (to reset dns)
func SetDNSWithRetry(node models.Node, address string) bool {
var reachable bool
if !hasPrereqs() {
return true
}
for counter := 0; !reachable && counter < 5; counter++ {
reachable = IsDNSReachable(address)
time.Sleep(time.Second << 1)
}
if !reachable {
logger.Log(0, "not setting dns (server unreachable), will try again later: "+address)
return true
} else if err := UpdateDNS(node.Interface, node.Network, address); err != nil {
logger.Log(0, "error applying dns"+err.Error())
} else if IsDNSWorking(node.Network, address) {
return true
}
resetDNS()
return false
}
func resetDNS() {
ncutils.RunCmd("systemctl restart systemd-resolved", true)
}
// SetDNS - sets the DNS of a local machine
func SetDNS(nameserver string) error {
bytes, err := os.ReadFile("/etc/resolv.conf")
if err != nil {
return err
}
resolvstring := string(bytes)
// //check whether s contains substring text
hasdns := strings.Contains(resolvstring, nameserver)
if hasdns {
return nil
}
resolv, err := os.OpenFile("/etc/resolv.conf", os.O_APPEND|os.O_WRONLY, 0644)
if err != nil {
return err
}
defer resolv.Close()
_, err = resolv.WriteString("nameserver " + nameserver + "\n")
return err
}
func hasPrereqs() bool {
if !ncutils.IsLinux() {
return false
}
_, err := exec.LookPath("resolvectl")
return err == nil
}
// UpdateDNS - updates local DNS of client
func UpdateDNS(ifacename string, network string, nameserver string) error {
if !ncutils.IsLinux() {
return nil
}
if ifacename == "" {
return fmt.Errorf("cannot set dns: interface name is blank")
}
if network == "" {
return fmt.Errorf("cannot set dns: network name is blank")
}
if nameserver == "" {
return fmt.Errorf("cannot set dns: nameserver is blank")
}
if !IsDNSReachable(nameserver) {
return fmt.Errorf(DNS_UNREACHABLE_ERROR + " : " + nameserver + ":53")
}
_, err := exec.LookPath("resolvectl")
if err != nil {
log.Println(err)
log.Println("WARNING: resolvectl not present. Unable to set dns. Install resolvectl or run manually.")
} else {
_, err = ncutils.RunCmd("resolvectl domain "+ifacename+" ~"+network, true)
if err != nil {
log.Println("WARNING: Error encountered setting domain on dns. Aborted setting dns.")
} else {
_, err = ncutils.RunCmd("resolvectl default-route "+ifacename+" false", true)
if err != nil {
log.Println("WARNING: Error encountered setting default-route on dns. Aborted setting dns.")
} else {
_, err = ncutils.RunCmd("resolvectl dns "+ifacename+" "+nameserver, true)
if err != nil {
log.Println("WARNING: Error encountered running resolvectl dns " + ifacename + " " + nameserver)
}
}
}
}
return err
}
// IsDNSReachable - checks if nameserver is reachable
func IsDNSReachable(nameserver string) bool {
port := "53"
protocols := [2]string{"tcp", "udp"}
for _, proto := range protocols {
timeout := time.Second
conn, err := net.DialTimeout(proto, net.JoinHostPort(nameserver, port), timeout)
if err != nil {
return false
}
if conn != nil {
defer conn.Close()
} else {
return false
}
}
return true
}
// IsDNSWorking - checks if record is returned by correct nameserver
func IsDNSWorking(network string, nameserver string) bool {
var isworking bool
servers, err := net.LookupNS("netmaker" + "." + network)
if err != nil {
return isworking
}
for _, ns := range servers {
if strings.Contains(ns.Host, nameserver) {
isworking = true
}
}
return isworking
}

View file

@ -245,7 +245,7 @@ func SetWGConfig(network string, peerupdate bool, peers []wgtypes.PeerConfig) er
if err != nil {
return err
}
servercfg := cfg.Server
nodecfg := cfg.Node
privkey, err := RetrievePrivKey(network)
@ -267,9 +267,7 @@ func SetWGConfig(network string, peerupdate bool, peers []wgtypes.PeerConfig) er
} else {
err = InitWireguard(&nodecfg, privkey, peers, false)
}
if nodecfg.DNSOn == "yes" {
_ = local.UpdateDNS(nodecfg.Interface, nodecfg.Network, servercfg.CoreDNSAddr)
}
return err
}