fix: engine exit when too many packets hit NFQUEUE

io/nfqueue.go

@@ -12,6 +12,7 @@ import (
 	"github.com/coreos/go-iptables/iptables"
 	"github.com/florianl/go-nfqueue"
 	"github.com/mdlayher/netlink"
+	"golang.org/x/sys/unix"
 )
 
 const (
@@ -152,6 +153,12 @@ func (n *nfqueuePacketIO) Register(ctx context.Context, cb PacketCallback) error
 			return okBoolToInt(cb(p, nil))
 		},
 		func(e error) int {
+			if opErr := (*netlink.OpError)(nil); errors.As(e, &opErr) {
+				if errors.Is(opErr.Err, unix.ENOBUFS) {
+					// Kernel buffer temporarily full, ignore
+					return 0
+				}
+			}
 			return okBoolToInt(cb(nil, e))
 		})
 	if err != nil {