netbird/client/internal/dns/resolvconf_linux.go
Zoltan Papp b64f5ffcb4
Mobile prerefactor (#680)
Small code cleaning in the iface package. These changes necessary to 
get a clean code in case if we involve more platforms. The OS related 
functions has been distributed into separate files and it has been 
mixed with not OS related logic. The goal is to get a clear picture 
of the layer between WireGuard and business logic.
2023-02-13 18:34:56 +01:00

86 lines
2.3 KiB
Go

package dns
import (
"fmt"
"os/exec"
"strings"
"github.com/netbirdio/netbird/iface"
log "github.com/sirupsen/logrus"
)
const resolvconfCommand = "resolvconf"
type resolvconf struct {
ifaceName string
}
func newResolvConfConfigurator(wgInterface *iface.WGIface) (hostManager, error) {
return &resolvconf{
ifaceName: wgInterface.Name(),
}, nil
}
func (r *resolvconf) applyDNSConfig(config hostDNSConfig) error {
var err error
if !config.routeAll {
err = r.restoreHostDNS()
if err != nil {
log.Error(err)
}
return fmt.Errorf("unable to configure DNS for this peer using resolvconf manager without a nameserver group with all domains configured")
}
var searchDomains string
appendedDomains := 0
for _, dConf := range config.domains {
if dConf.matchOnly || dConf.disabled {
continue
}
if appendedDomains >= fileMaxNumberOfSearchDomains {
// lets log all skipped domains
log.Infof("already appended %d domains to search list. Skipping append of %s domain", fileMaxNumberOfSearchDomains, dConf.domain)
continue
}
if fileSearchLineBeginCharCount+len(searchDomains) > fileMaxLineCharsLimit {
// lets log all skipped domains
log.Infof("search list line is larger than %d characters. Skipping append of %s domain", fileMaxLineCharsLimit, dConf.domain)
continue
}
searchDomains += " " + dConf.domain
appendedDomains++
}
content := fmt.Sprintf(fileGeneratedResolvConfContentFormat, fileDefaultResolvConfBackupLocation, config.serverIP, searchDomains)
err = r.applyConfig(content)
if err != nil {
return err
}
log.Infof("added %d search domains. Search list: %s", appendedDomains, searchDomains)
return nil
}
func (r *resolvconf) restoreHostDNS() error {
cmd := exec.Command(resolvconfCommand, "-f", "-d", r.ifaceName)
_, err := cmd.Output()
if err != nil {
return fmt.Errorf("got an error while removing resolvconf configuration for %s interface, error: %s", r.ifaceName, err)
}
return nil
}
func (r *resolvconf) applyConfig(content string) error {
cmd := exec.Command(resolvconfCommand, "-x", "-a", r.ifaceName)
cmd.Stdin = strings.NewReader(content)
_, err := cmd.Output()
if err != nil {
return fmt.Errorf("got an error while appying resolvconf configuration for %s interface, error: %s", r.ifaceName, err)
}
return nil
}