mctp: Add test utils

Add a new object for shared test utilities
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/mctp/Makefile

 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_MCTP) += mctp.o
 mctp-objs := af_mctp.o device.o route.o neigh.o
+
+# tests
+obj-$(CONFIG_MCTP_TEST) += test/utils.o

net/mctp/test/utils.c

+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/netdevice.h>
+#include <linux/mctp.h>
+#include <linux/if_arp.h>
+
+#include <net/mctpdevice.h>
+#include <net/pkt_sched.h>
+
+#include "utils.h"
+
+static netdev_tx_t mctp_test_dev_tx(struct sk_buff *skb,
+				    struct net_device *ndev)
+{
+	kfree(skb);
+	return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops mctp_test_netdev_ops = {
+	.ndo_start_xmit = mctp_test_dev_tx,
+};
+
+static void mctp_test_dev_setup(struct net_device *ndev)
+{
+	ndev->type = ARPHRD_MCTP;
+	ndev->mtu = MCTP_DEV_TEST_MTU;
+	ndev->hard_header_len = 0;
+	ndev->addr_len = 0;
+	ndev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
+	ndev->flags = IFF_NOARP;
+	ndev->netdev_ops = &mctp_test_netdev_ops;
+	ndev->needs_free_netdev = true;
+}
+
+struct mctp_test_dev *mctp_test_create_dev(void)
+{
+	struct mctp_test_dev *dev;
+	struct net_device *ndev;
+	int rc;
+
+	ndev = alloc_netdev(sizeof(*dev), "mctptest%d", NET_NAME_ENUM,
+			    mctp_test_dev_setup);
+	if (!ndev)
+		return NULL;
+
+	dev = netdev_priv(ndev);
+	dev->ndev = ndev;
+
+	rcu_read_lock();
+	dev->mdev = __mctp_dev_get(ndev);
+	mctp_dev_hold(dev->mdev);
+	rcu_read_unlock();
+
+	rc = register_netdev(ndev);
+	if (rc) {
+		free_netdev(ndev);
+		return NULL;
+	}
+
+	return dev;
+}
+
+void mctp_test_destroy_dev(struct mctp_test_dev *dev)
+{
+	mctp_dev_put(dev->mdev);
+	unregister_netdev(dev->ndev);
+}

net/mctp/test/utils.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __NET_MCTP_TEST_UTILS_H
+#define __NET_MCTP_TEST_UTILS_H
+
+#include <kunit/test.h>
+
+#define MCTP_DEV_TEST_MTU	68
+
+struct mctp_test_dev {
+	struct net_device *ndev;
+	struct mctp_dev *mdev;
+};
+
+struct mctp_test_dev;
+
+struct mctp_test_dev *mctp_test_create_dev(void);
+void mctp_test_destroy_dev(struct mctp_test_dev *dev);
+
+#endif /* __NET_MCTP_TEST_UTILS_H */