Handle ICMP not permitted errors

internal/pmtud/errors.go

@@ -5,10 +5,12 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"strings"
 	"time"
 )
 
 var (
+	ErrICMPNotPermitted                            = errors.New("ICMP not permitted")
 	ErrICMPDestinationUnreachable                  = errors.New("ICMP destination unreachable")
 	ErrICMPCommunicationAdministrativelyProhibited = errors.New("communication administratively prohibited")
 	ErrICMPBodyUnsupported                         = errors.New("ICMP body type is not supported")
@@ -16,6 +18,8 @@ var (
 
 func wrapConnErr(err error, timedCtx context.Context, pingTimeout time.Duration) error { //nolint:revive
 	switch {
+	case strings.HasSuffix(err.Error(), "sendto: operation not permitted"):
+		err = fmt.Errorf("%w", ErrICMPNotPermitted)
 	case errors.Is(timedCtx.Err(), context.DeadlineExceeded):
 		err = fmt.Errorf("%w (timed out after %s)", net.ErrClosed, pingTimeout)
 	case timedCtx.Err() != nil: