mirror of
https://github.com/netbirdio/netbird.git
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17b1099032
* Fix using wrong array index in log to avoid potential panic * Increase gRPC connection timeout and add the timeout resolv.conf option This makes sure the dns client is able to failover to a second configured nameserver, if present. That is the case then when using the dns `file` manager and a resolv.conf file generated for netbird. * On file backup restore, remove the first NS if it's the netbird NS * Bump dns mangager discovery message from debug to info to ease debugging
109 lines
3.0 KiB
Go
109 lines
3.0 KiB
Go
//go:build !android
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package dns
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import (
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"bytes"
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"fmt"
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"net/netip"
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"os/exec"
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log "github.com/sirupsen/logrus"
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)
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const resolvconfCommand = "resolvconf"
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type resolvconf struct {
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ifaceName string
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originalSearchDomains []string
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originalNameServers []string
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othersConfigs []string
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}
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// supported "openresolv" only
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func newResolvConfConfigurator(wgInterface string) (hostManager, error) {
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resolvConfEntries, err := parseDefaultResolvConf()
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if err != nil {
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log.Errorf("could not read original search domains from %s: %s", defaultResolvConfPath, err)
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}
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return &resolvconf{
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ifaceName: wgInterface,
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originalSearchDomains: resolvConfEntries.searchDomains,
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originalNameServers: resolvConfEntries.nameServers,
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othersConfigs: resolvConfEntries.others,
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}, nil
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}
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func (r *resolvconf) supportCustomPort() bool {
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return false
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}
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func (r *resolvconf) applyDNSConfig(config HostDNSConfig) error {
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var err error
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if !config.RouteAll {
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err = r.restoreHostDNS()
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if err != nil {
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log.Errorf("restore host dns: %s", err)
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}
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return fmt.Errorf("unable to configure DNS for this peer using resolvconf manager without a nameserver group with all domains configured")
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}
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searchDomainList := searchDomains(config)
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searchDomainList = mergeSearchDomains(searchDomainList, r.originalSearchDomains)
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options := prepareOptionsWithTimeout(r.othersConfigs, int(dnsFailoverTimeout.Seconds()), dnsFailoverAttempts)
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buf := prepareResolvConfContent(
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searchDomainList,
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append([]string{config.ServerIP}, r.originalNameServers...),
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options)
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// create a backup for unclean shutdown detection before the resolv.conf is changed
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if err := createUncleanShutdownIndicator(defaultResolvConfPath, resolvConfManager, config.ServerIP); err != nil {
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log.Errorf("failed to create unclean shutdown resolv.conf backup: %s", err)
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}
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err = r.applyConfig(buf)
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if err != nil {
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return fmt.Errorf("apply config: %w", err)
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}
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log.Infof("added %d search domains. Search list: %s", len(searchDomainList), searchDomainList)
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return nil
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}
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func (r *resolvconf) restoreHostDNS() error {
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// openresolv only, debian resolvconf doesn't support "-f"
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cmd := exec.Command(resolvconfCommand, "-f", "-d", r.ifaceName)
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_, err := cmd.Output()
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if err != nil {
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return fmt.Errorf("removing resolvconf configuration for %s interface, error: %w", r.ifaceName, err)
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}
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if err := removeUncleanShutdownIndicator(); err != nil {
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log.Errorf("failed to remove unclean shutdown resolv.conf backup: %s", err)
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}
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return nil
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}
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func (r *resolvconf) applyConfig(content bytes.Buffer) error {
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// openresolv only, debian resolvconf doesn't support "-x"
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cmd := exec.Command(resolvconfCommand, "-x", "-a", r.ifaceName)
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cmd.Stdin = &content
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_, err := cmd.Output()
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if err != nil {
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return fmt.Errorf("applying resolvconf configuration for %s interface, error: %w", r.ifaceName, err)
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}
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return nil
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}
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func (r *resolvconf) restoreUncleanShutdownDNS(*netip.Addr) error {
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if err := r.restoreHostDNS(); err != nil {
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return fmt.Errorf("restoring dns for interface %s: %w", r.ifaceName, err)
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}
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return nil
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}
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