@@ -11,6 +11,7 @@ import (
1111"sync"
1212"time"
1313
14+ "github.com/cenkalti/backoff/v4"
1415"github.com/google/uuid"
1516"go4.org/netipx"
1617"golang.org/x/xerrors"
@@ -424,24 +425,43 @@ func (c *Conn) Ping(ctx context.Context, ip netip.Addr) (time.Duration, error) {
424425// address is reachable. It's the callers responsibility to provide
425426// a timeout, otherwise this function will block forever.
426427func (c * Conn )AwaitReachable (ctx context.Context ,ip netip.Addr )bool {
427- ticker := time .NewTicker (time .Millisecond * 100 )
428- defer ticker .Stop ()
429- completedCtx ,completed := context .WithCancel (ctx )
428+ ctx ,cancel := context .WithCancel (ctx )
429+ defer cancel ()// Cancel all pending pings on exit.
430+
431+ completedCtx ,completed := context .WithCancel (context .Background ())
432+ defer completed ()
433+
430434run := func () {
431- ctx ,cancelFunc := context .WithTimeout (completedCtx ,time .Second )
432- defer cancelFunc ()
435+ // Safety timeout, initially we'll have around 10-20 goroutines
436+ // running in parallel. The exponential backoff will converge
437+ // around ~1 ping / 30s, this means we'll have around 10-20
438+ // goroutines pending towards the end as well.
439+ ctx ,cancel := context .WithTimeout (ctx ,5 * time .Minute )
440+ defer cancel ()
441+
433442_ ,err := c .Ping (ctx ,ip )
434443if err == nil {
435444completed ()
436445}
437446}
447+
448+ eb := backoff .NewExponentialBackOff ()
449+ eb .MaxElapsedTime = 0
450+ eb .InitialInterval = 50 * time .Millisecond
451+ eb .MaxInterval = 30 * time .Second
452+ // Consume the first interval since
453+ // we'll fire off a ping immediately.
454+ _ = eb .NextBackOff ()
455+
456+ t := backoff .NewTicker (eb )
457+ defer t .Stop ()
458+
438459go run ()
439- defer completed ()
440460for {
441461select {
442462case <- completedCtx .Done ():
443463return true
444- case <- ticker .C :
464+ case <- t .C :
445465// Pings can take a while, so we can run multiple
446466// in parallel to return ASAP.
447467go run ()