// SPDX-License-Identifier: GPL-2.0

#include <linux/netdevice.h>
#include <linux/mctp.h>
#include <linux/if_arp.h>

#include <net/mctp.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)
{
        struct mctp_test_dev *dev = netdev_priv(ndev);

        skb_queue_tail(&dev->pkts, 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->tx_queue_len = 0;
        ndev->flags = IFF_NOARP;
        ndev->netdev_ops = &mctp_test_netdev_ops;
        ndev->needs_free_netdev = true;
}

static struct mctp_test_dev *__mctp_test_create_dev(unsigned short lladdr_len,
                                                    const unsigned char *lladdr)
{
        struct mctp_test_dev *dev;
        struct net_device *ndev;
        int rc;

        if (WARN_ON(lladdr_len > MAX_ADDR_LEN))
                return NULL;

        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;
        ndev->addr_len = lladdr_len;
        dev_addr_set(ndev, lladdr);
        skb_queue_head_init(&dev->pkts);

        rc = register_netdev(ndev);
        if (rc) {
                free_netdev(ndev);
                return NULL;
        }

        rcu_read_lock();
        dev->mdev = __mctp_dev_get(ndev);
        dev->mdev->net = mctp_default_net(dev_net(ndev));
        rcu_read_unlock();

        /* bring the device up; we want to be able to TX immediately */
        rtnl_lock();
        dev_open(ndev, NULL);
        rtnl_unlock();

        return dev;
}

struct mctp_test_dev *mctp_test_create_dev(void)
{
        return __mctp_test_create_dev(0, NULL);
}

struct mctp_test_dev *mctp_test_create_dev_lladdr(unsigned short lladdr_len,
                                                  const unsigned char *lladdr)
{
        return __mctp_test_create_dev(lladdr_len, lladdr);
}

void mctp_test_destroy_dev(struct mctp_test_dev *dev)
{
        skb_queue_purge(&dev->pkts);
        mctp_dev_put(dev->mdev);
        unregister_netdev(dev->ndev);
}

static int mctp_test_dst_output(struct mctp_dst *dst, struct sk_buff *skb)
{
        skb->dev = dst->dev->dev;
        dev_queue_xmit(skb);

        return 0;
}

/* local version of mctp_route_alloc() */
static struct mctp_test_route *mctp_route_test_alloc(void)
{
        struct mctp_test_route *rt;

        rt = kzalloc_obj(*rt);
        if (!rt)
                return NULL;

        INIT_LIST_HEAD(&rt->rt.list);
        refcount_set(&rt->rt.refs, 1);
        rt->rt.output = mctp_test_dst_output;

        return rt;
}

struct mctp_test_route *mctp_test_create_route_direct(struct net *net,
                                                      struct mctp_dev *dev,
                                                      mctp_eid_t eid,
                                                      unsigned int mtu)
{
        struct mctp_test_route *rt;

        rt = mctp_route_test_alloc();
        if (!rt)
                return NULL;

        rt->rt.min = eid;
        rt->rt.max = eid;
        rt->rt.mtu = mtu;
        rt->rt.type = RTN_UNSPEC;
        rt->rt.dst_type = MCTP_ROUTE_DIRECT;
        if (dev)
                mctp_dev_hold(dev);
        rt->rt.dev = dev;

        list_add_rcu(&rt->rt.list, &net->mctp.routes);

        return rt;
}

struct mctp_test_route *mctp_test_create_route_gw(struct net *net,
                                                  unsigned int netid,
                                                  mctp_eid_t eid,
                                                  mctp_eid_t gw,
                                                  unsigned int mtu)
{
        struct mctp_test_route *rt;

        rt = mctp_route_test_alloc();
        if (!rt)
                return NULL;

        rt->rt.min = eid;
        rt->rt.max = eid;
        rt->rt.mtu = mtu;
        rt->rt.type = RTN_UNSPEC;
        rt->rt.dst_type = MCTP_ROUTE_GATEWAY;
        rt->rt.gateway.eid = gw;
        rt->rt.gateway.net = netid;

        list_add_rcu(&rt->rt.list, &net->mctp.routes);

        return rt;
}

/* Convenience function for our test dst; release with mctp_dst_release() */
void mctp_test_dst_setup(struct kunit *test, struct mctp_dst *dst,
                         struct mctp_test_dev *dev, unsigned int mtu)
{
        KUNIT_EXPECT_NOT_ERR_OR_NULL(test, dev);

        memset(dst, 0, sizeof(*dst));

        dst->dev = dev->mdev;
        __mctp_dev_get(dst->dev->dev);
        dst->mtu = mtu;
        dst->output = mctp_test_dst_output;
}

void mctp_test_route_destroy(struct kunit *test, struct mctp_test_route *rt)
{
        unsigned int refs;

        rtnl_lock();
        list_del_rcu(&rt->rt.list);
        rtnl_unlock();

        if (rt->rt.dst_type == MCTP_ROUTE_DIRECT && rt->rt.dev)
                mctp_dev_put(rt->rt.dev);

        refs = refcount_read(&rt->rt.refs);
        KUNIT_ASSERT_EQ_MSG(test, refs, 1, "route ref imbalance");

        kfree_rcu(&rt->rt, rcu);
}

void mctp_test_skb_set_dev(struct sk_buff *skb, struct mctp_test_dev *dev)
{
        struct mctp_skb_cb *cb;

        cb = mctp_cb(skb);
        cb->net = READ_ONCE(dev->mdev->net);
        skb->dev = dev->ndev;
}

struct sk_buff *mctp_test_create_skb(const struct mctp_hdr *hdr,
                                     unsigned int data_len)
{
        size_t hdr_len = sizeof(*hdr);
        struct sk_buff *skb;
        unsigned int i;
        u8 *buf;

        skb = alloc_skb(hdr_len + data_len, GFP_KERNEL);
        if (!skb)
                return NULL;

        __mctp_cb(skb);
        memcpy(skb_put(skb, hdr_len), hdr, hdr_len);

        buf = skb_put(skb, data_len);
        for (i = 0; i < data_len; i++)
                buf[i] = i & 0xff;

        return skb;
}

struct sk_buff *__mctp_test_create_skb_data(const struct mctp_hdr *hdr,
                                            const void *data, size_t data_len)
{
        size_t hdr_len = sizeof(*hdr);
        struct sk_buff *skb;

        skb = alloc_skb(hdr_len + data_len, GFP_KERNEL);
        if (!skb)
                return NULL;

        __mctp_cb(skb);
        memcpy(skb_put(skb, hdr_len), hdr, hdr_len);
        memcpy(skb_put(skb, data_len), data, data_len);

        return skb;
}

void mctp_test_bind_run(struct kunit *test,
                        const struct mctp_test_bind_setup *setup,
                        int *ret_bind_errno, struct socket **sock)
{
        struct sockaddr_mctp addr;
        int rc;

        *ret_bind_errno = -EIO;

        rc = sock_create_kern(&init_net, AF_MCTP, SOCK_DGRAM, 0, sock);
        KUNIT_ASSERT_EQ(test, rc, 0);

        /* connect() if requested */
        if (setup->have_peer) {
                memset(&addr, 0x0, sizeof(addr));
                addr.smctp_family = AF_MCTP;
                addr.smctp_network = setup->peer_net;
                addr.smctp_addr.s_addr = setup->peer_addr;
                /* connect() type must match bind() type */
                addr.smctp_type = setup->bind_type;
                rc = kernel_connect(*sock, (struct sockaddr_unsized *)&addr,
                                    sizeof(addr), 0);
                KUNIT_EXPECT_EQ(test, rc, 0);
        }

        /* bind() */
        memset(&addr, 0x0, sizeof(addr));
        addr.smctp_family = AF_MCTP;
        addr.smctp_network = setup->bind_net;
        addr.smctp_addr.s_addr = setup->bind_addr;
        addr.smctp_type = setup->bind_type;

        *ret_bind_errno =
                kernel_bind(*sock, (struct sockaddr_unsized *)&addr,
                            sizeof(addr));
}