mirror of
https://github.com/netbirdio/netbird.git
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070a0a7bf1
On network changes the client restarted the whole engine. That is heavy-handed and slow: it tears down working state to recover from a transition the engine could handle itself. This replaces the restart with proper network event handling. Suspend the retry loops while no network is available. Instead of burning through backoff intervals against an unreachable network, the reconnection loops park until the OS reports a usable network again. Reconnect immediately on a network switch. When the OS hands us a new network, connections bound to the old one are swept and re-dialed right away, rather than waiting for a timeout to notice they are dead.
123 lines
3.2 KiB
Go
123 lines
3.2 KiB
Go
package client
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import (
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"context"
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"errors"
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"fmt"
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"sync/atomic"
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"time"
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log "github.com/sirupsen/logrus"
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"github.com/netbirdio/netbird/client/netsweep"
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auth "github.com/netbirdio/netbird/shared/relay/auth/hmac"
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)
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const (
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maxConcurrentServers = 7
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defaultConnectionTimeout = 30 * time.Second
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)
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type connResult struct {
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RelayClient *Client
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Url string
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Err error
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}
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type ServerPicker struct {
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TokenStore *auth.TokenStore
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ServerURLs atomic.Value
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PeerID string
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MTU uint16
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ConnectionTimeout time.Duration
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TransportFallback *transportFallback
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Sweeper *netsweep.Sweeper
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}
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func (sp *ServerPicker) PickServer(parentCtx context.Context) (*Client, error) {
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ctx, cancel := context.WithTimeout(parentCtx, sp.ConnectionTimeout)
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defer cancel()
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totalServers := len(sp.ServerURLs.Load().([]string))
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connResultChan := make(chan connResult, totalServers)
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successChan := make(chan connResult, 1)
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errChan := make(chan error, 1)
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concurrentLimiter := make(chan struct{}, maxConcurrentServers)
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log.Debugf("pick server from list: %v", sp.ServerURLs.Load().([]string))
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for _, url := range sp.ServerURLs.Load().([]string) {
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// todo check if we have a successful connection so we do not need to connect to other servers
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concurrentLimiter <- struct{}{}
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go func(url string) {
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defer func() {
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<-concurrentLimiter
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}()
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sp.startConnection(parentCtx, connResultChan, url)
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}(url)
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}
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go sp.processConnResults(connResultChan, successChan, errChan)
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select {
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case cr, ok := <-successChan:
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if !ok {
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return nil, <-errChan
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}
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log.Infof("chosen home Relay server: %s", cr.Url)
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return cr.RelayClient, nil
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case <-ctx.Done():
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return nil, fmt.Errorf("connect to relay server: %w", ctx.Err())
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}
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}
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func (sp *ServerPicker) startConnection(ctx context.Context, resultChan chan connResult, url string) {
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log.Infof("try to connecting to relay server: %s", url)
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relayClient := NewClient(url, sp.TokenStore, sp.PeerID, sp.MTU)
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relayClient.SetTransportFallback(sp.TransportFallback)
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relayClient.sweeper = sp.Sweeper
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err := relayClient.Connect(ctx)
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resultChan <- connResult{
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RelayClient: relayClient,
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Url: url,
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Err: err,
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}
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}
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func (sp *ServerPicker) processConnResults(resultChan chan connResult, successChan chan connResult, errChan chan error) {
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var hasSuccess bool
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var errs []error
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for numOfResults := 0; numOfResults < cap(resultChan); numOfResults++ {
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cr := <-resultChan
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if cr.Err != nil {
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log.Tracef("failed to connect to Relay server: %s: %v", cr.Url, cr.Err)
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errs = append(errs, cr.Err)
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continue
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}
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log.Infof("connected to Relay server: %s", cr.Url)
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if hasSuccess {
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log.Infof("closing unnecessary Relay connection to: %s", cr.Url)
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if err := cr.RelayClient.Close(); err != nil {
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log.Errorf("failed to close connection to %s: %v", cr.Url, err)
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}
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continue
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}
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hasSuccess = true
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successChan <- cr
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}
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if !hasSuccess {
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errChan <- pickErr(errs)
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}
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close(successChan)
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}
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// pickErr combines per-server connection failures into a single error.
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func pickErr(errs []error) error {
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if len(errs) == 0 {
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return errors.New("no relay server available")
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}
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return errors.Join(errs...)
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}
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