[#240] pool: Add `SyncContainerWithNetwork`

It is a helper function that uses a `Pool` to fetch network information and
apply it to the container (change the container if it does not fit the
network). Currently, only applies the homomorphic hashing parameter.

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

pool/pool.go

@@ -1811,3 +1811,26 @@ func (p *Pool) Close() {
 	p.cancel()
 	<-p.closedCh
 }
+
+// SyncContainerWithNetwork applies network configuration received via
+// the Pool to the container. Changes the container if it does not satisfy
+// network configuration.
+//
+// Pool and container MUST not be nil.
+//
+// Returns any error that does not allow reading configuration
+// from the network.
+func SyncContainerWithNetwork(ctx context.Context, cnr *container.Container, p *Pool) error {
+	ni, err := p.NetworkInfo(ctx)
+	if err != nil {
+		return fmt.Errorf("network info: %w", err)
+	}
+
+	if ni == nil {
+		return errors.New("empty network info")
+	}
+
+	container.ApplyNetworkConfig(cnr, *ni)
+
+	return nil
+}