netbird/client/internal/dns/resolvconf_unix.go

110 lines
2.9 KiB
Go

//go:build (linux && !android) || freebsd
package dns
import (
"bytes"
"fmt"
"net/netip"
"os/exec"
log "github.com/sirupsen/logrus"
"github.com/netbirdio/netbird/client/internal/statemanager"
)
const resolvconfCommand = "resolvconf"
type resolvconf struct {
ifaceName string
originalSearchDomains []string
originalNameServers []string
othersConfigs []string
}
// supported "openresolv" only
func newResolvConfConfigurator(wgInterface string) (*resolvconf, error) {
resolvConfEntries, err := parseDefaultResolvConf()
if err != nil {
log.Errorf("could not read original search domains from %s: %s", defaultResolvConfPath, err)
}
return &resolvconf{
ifaceName: wgInterface,
originalSearchDomains: resolvConfEntries.searchDomains,
originalNameServers: resolvConfEntries.nameServers,
othersConfigs: resolvConfEntries.others,
}, nil
}
func (r *resolvconf) supportCustomPort() bool {
return false
}
func (r *resolvconf) applyDNSConfig(config HostDNSConfig, stateManager *statemanager.Manager) error {
var err error
if !config.RouteAll {
err = r.restoreHostDNS()
if err != nil {
log.Errorf("restore host dns: %s", err)
}
return fmt.Errorf("unable to configure DNS for this peer using resolvconf manager without a nameserver group with all domains configured")
}
searchDomainList := searchDomains(config)
searchDomainList = mergeSearchDomains(searchDomainList, r.originalSearchDomains)
options := prepareOptionsWithTimeout(r.othersConfigs, int(dnsFailoverTimeout.Seconds()), dnsFailoverAttempts)
buf := prepareResolvConfContent(
searchDomainList,
append([]string{config.ServerIP}, r.originalNameServers...),
options)
state := &ShutdownState{
ManagerType: resolvConfManager,
WgIface: r.ifaceName,
}
if err := stateManager.UpdateState(state); err != nil {
log.Errorf("failed to update shutdown state: %s", err)
}
err = r.applyConfig(buf)
if err != nil {
return fmt.Errorf("apply config: %w", err)
}
log.Infof("added %d search domains. Search list: %s", len(searchDomainList), searchDomainList)
return nil
}
func (r *resolvconf) restoreHostDNS() error {
// openresolv only, debian resolvconf doesn't support "-f"
cmd := exec.Command(resolvconfCommand, "-f", "-d", r.ifaceName)
_, err := cmd.Output()
if err != nil {
return fmt.Errorf("removing resolvconf configuration for %s interface: %w", r.ifaceName, err)
}
return nil
}
func (r *resolvconf) applyConfig(content bytes.Buffer) error {
// openresolv only, debian resolvconf doesn't support "-x"
cmd := exec.Command(resolvconfCommand, "-x", "-a", r.ifaceName)
cmd.Stdin = &content
_, err := cmd.Output()
if err != nil {
return fmt.Errorf("applying resolvconf configuration for %s interface: %w", r.ifaceName, err)
}
return nil
}
func (r *resolvconf) restoreUncleanShutdownDNS(*netip.Addr) error {
if err := r.restoreHostDNS(); err != nil {
return fmt.Errorf("restoring dns for interface %s: %w", r.ifaceName, err)
}
return nil
}