// SPDX-License-Identifier: GPL-2.0
/*
 *  Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 *  Generic netlink support functions to configure an SMC-R PNET table
 *
 *  Copyright IBM Corp. 2016
 *
 *  Author(s):  Thomas Richter <tmricht@linux.vnet.ibm.com>
 */

#include <linux/module.h>
#include <linux/list.h>
#include <linux/ctype.h>
#include <net/netlink.h>
#include <net/genetlink.h>

#include <uapi/linux/if.h>
#include <uapi/linux/smc.h>

#include <rdma/ib_verbs.h>

#include "smc_pnet.h"
#include "smc_ib.h"

#define SMC_MAX_PNET_ID_LEN     16      /* Max. length of PNET id */

static struct nla_policy smc_pnet_policy[SMC_PNETID_MAX + 1] = {
        [SMC_PNETID_NAME] = {
                .type = NLA_NUL_STRING,
                .len = SMC_MAX_PNET_ID_LEN - 1
        },
        [SMC_PNETID_ETHNAME] = {
                .type = NLA_NUL_STRING,
                .len = IFNAMSIZ - 1
        },
        [SMC_PNETID_IBNAME] = {
                .type = NLA_NUL_STRING,
                .len = IB_DEVICE_NAME_MAX - 1
        },
        [SMC_PNETID_IBPORT] = { .type = NLA_U8 }
};

static struct genl_family smc_pnet_nl_family;

/**
 * struct smc_pnettable - SMC PNET table anchor
 * @lock: Lock for list action
 * @pnetlist: List of PNETIDs
 */
static struct smc_pnettable {
        rwlock_t lock;
        struct list_head pnetlist;
} smc_pnettable = {
        .pnetlist = LIST_HEAD_INIT(smc_pnettable.pnetlist),
        .lock = __RW_LOCK_UNLOCKED(smc_pnettable.lock)
};

/**
 * struct smc_pnetentry - pnet identifier name entry
 * @list: List node.
 * @pnet_name: Pnet identifier name
 * @ndev: pointer to network device.
 * @smcibdev: Pointer to IB device.
 */
struct smc_pnetentry {
        struct list_head list;
        char pnet_name[SMC_MAX_PNET_ID_LEN + 1];
        struct net_device *ndev;
        struct smc_ib_device *smcibdev;
        u8 ib_port;
};

/* Check if two RDMA device entries are identical. Use device name and port
 * number for comparison.
 */
static bool smc_pnet_same_ibname(struct smc_pnetentry *pnetelem, char *ibname,
                                 u8 ibport)
{
        return pnetelem->ib_port == ibport &&
               !strncmp(pnetelem->smcibdev->ibdev->name, ibname,
                        sizeof(pnetelem->smcibdev->ibdev->name));
}

/* Find a pnetid in the pnet table.
 */
static struct smc_pnetentry *smc_pnet_find_pnetid(char *pnet_name)
{
        struct smc_pnetentry *pnetelem, *found_pnetelem = NULL;

        read_lock(&smc_pnettable.lock);
        list_for_each_entry(pnetelem, &smc_pnettable.pnetlist, list) {
                if (!strncmp(pnetelem->pnet_name, pnet_name,
                             sizeof(pnetelem->pnet_name))) {
                        found_pnetelem = pnetelem;
                        break;
                }
        }
        read_unlock(&smc_pnettable.lock);
        return found_pnetelem;
}

/* Remove a pnetid from the pnet table.
 */
static int smc_pnet_remove_by_pnetid(char *pnet_name)
{
        struct smc_pnetentry *pnetelem, *tmp_pe;
        int rc = -ENOENT;

        write_lock(&smc_pnettable.lock);
        list_for_each_entry_safe(pnetelem, tmp_pe, &smc_pnettable.pnetlist,
                                 list) {
                if (!strncmp(pnetelem->pnet_name, pnet_name,
                             sizeof(pnetelem->pnet_name))) {
                        list_del(&pnetelem->list);
                        dev_put(pnetelem->ndev);
                        kfree(pnetelem);
                        rc = 0;
                        break;
                }
        }
        write_unlock(&smc_pnettable.lock);
        return rc;
}

/* Remove a pnet entry mentioning a given network device from the pnet table.
 */
static int smc_pnet_remove_by_ndev(struct net_device *ndev)
{
        struct smc_pnetentry *pnetelem, *tmp_pe;
        int rc = -ENOENT;

        write_lock(&smc_pnettable.lock);
        list_for_each_entry_safe(pnetelem, tmp_pe, &smc_pnettable.pnetlist,
                                 list) {
                if (pnetelem->ndev == ndev) {
                        list_del(&pnetelem->list);
                        dev_put(pnetelem->ndev);
                        kfree(pnetelem);
                        rc = 0;
                        break;
                }
        }
        write_unlock(&smc_pnettable.lock);
        return rc;
}

/* Remove a pnet entry mentioning a given ib device from the pnet table.
 */
int smc_pnet_remove_by_ibdev(struct smc_ib_device *ibdev)
{
        struct smc_pnetentry *pnetelem, *tmp_pe;
        int rc = -ENOENT;

        write_lock(&smc_pnettable.lock);
        list_for_each_entry_safe(pnetelem, tmp_pe, &smc_pnettable.pnetlist,
                                 list) {
                if (pnetelem->smcibdev == ibdev) {
                        list_del(&pnetelem->list);
                        dev_put(pnetelem->ndev);
                        kfree(pnetelem);
                        rc = 0;
                        break;
                }
        }
        write_unlock(&smc_pnettable.lock);
        return rc;
}

/* Append a pnetid to the end of the pnet table if not already on this list.
 */
static int smc_pnet_enter(struct smc_pnetentry *new_pnetelem)
{
        struct smc_pnetentry *pnetelem;
        int rc = -EEXIST;

        write_lock(&smc_pnettable.lock);
        list_for_each_entry(pnetelem, &smc_pnettable.pnetlist, list) {
                if (!strncmp(pnetelem->pnet_name, new_pnetelem->pnet_name,
                             sizeof(new_pnetelem->pnet_name)) ||
                    !strncmp(pnetelem->ndev->name, new_pnetelem->ndev->name,
                             sizeof(new_pnetelem->ndev->name)) ||
                    smc_pnet_same_ibname(pnetelem,
                                         new_pnetelem->smcibdev->ibdev->name,
                                         new_pnetelem->ib_port)) {
                        dev_put(pnetelem->ndev);
                        goto found;
                }
        }
        list_add_tail(&new_pnetelem->list, &smc_pnettable.pnetlist);
        rc = 0;
found:
        write_unlock(&smc_pnettable.lock);
        return rc;
}

/* The limit for pnetid is 16 characters.
 * Valid characters should be (single-byte character set) a-z, A-Z, 0-9.
 * Lower case letters are converted to upper case.
 * Interior blanks should not be used.
 */
static bool smc_pnetid_valid(const char *pnet_name, char *pnetid)
{
        char *bf = skip_spaces(pnet_name);
        size_t len = strlen(bf);
        char *end = bf + len;

        if (!len)
                return false;
        while (--end >= bf && isspace(*end))
                ;
        if (end - bf >= SMC_MAX_PNET_ID_LEN)
                return false;
        while (bf <= end) {
                if (!isalnum(*bf))
                        return false;
                *pnetid++ = islower(*bf) ? toupper(*bf) : *bf;
                bf++;
        }
        *pnetid = '\0';
        return true;
}

/* Find an infiniband device by a given name. The device might not exist. */
static struct smc_ib_device *smc_pnet_find_ib(char *ib_name)
{
        struct smc_ib_device *ibdev;

        spin_lock(&smc_ib_devices.lock);
        list_for_each_entry(ibdev, &smc_ib_devices.list, list) {
                if (!strncmp(ibdev->ibdev->name, ib_name,
                             sizeof(ibdev->ibdev->name))) {
                        goto out;
                }
        }
        ibdev = NULL;
out:
        spin_unlock(&smc_ib_devices.lock);
        return ibdev;
}

/* Parse the supplied netlink attributes and fill a pnetentry structure.
 * For ethernet and infiniband device names verify that the devices exist.
 */
static int smc_pnet_fill_entry(struct net *net, struct smc_pnetentry *pnetelem,
                               struct nlattr *tb[])
{
        char *string, *ibname;
        int rc;

        memset(pnetelem, 0, sizeof(*pnetelem));
        INIT_LIST_HEAD(&pnetelem->list);

        rc = -EINVAL;
        if (!tb[SMC_PNETID_NAME])
                goto error;
        string = (char *)nla_data(tb[SMC_PNETID_NAME]);
        if (!smc_pnetid_valid(string, pnetelem->pnet_name))
                goto error;

        rc = -EINVAL;
        if (!tb[SMC_PNETID_ETHNAME])
                goto error;
        rc = -ENOENT;
        string = (char *)nla_data(tb[SMC_PNETID_ETHNAME]);
        pnetelem->ndev = dev_get_by_name(net, string);
        if (!pnetelem->ndev)
                goto error;

        rc = -EINVAL;
        if (!tb[SMC_PNETID_IBNAME])
                goto error;
        rc = -ENOENT;
        ibname = (char *)nla_data(tb[SMC_PNETID_IBNAME]);
        ibname = strim(ibname);
        pnetelem->smcibdev = smc_pnet_find_ib(ibname);
        if (!pnetelem->smcibdev)
                goto error;

        rc = -EINVAL;
        if (!tb[SMC_PNETID_IBPORT])
                goto error;
        pnetelem->ib_port = nla_get_u8(tb[SMC_PNETID_IBPORT]);
        if (pnetelem->ib_port < 1 || pnetelem->ib_port > SMC_MAX_PORTS)
                goto error;

        return 0;

error:
        if (pnetelem->ndev)
                dev_put(pnetelem->ndev);
        return rc;
}

/* Convert an smc_pnetentry to a netlink attribute sequence */
static int smc_pnet_set_nla(struct sk_buff *msg, struct smc_pnetentry *pnetelem)
{
        if (nla_put_string(msg, SMC_PNETID_NAME, pnetelem->pnet_name) ||
            nla_put_string(msg, SMC_PNETID_ETHNAME, pnetelem->ndev->name) ||
            nla_put_string(msg, SMC_PNETID_IBNAME,
                           pnetelem->smcibdev->ibdev->name) ||
            nla_put_u8(msg, SMC_PNETID_IBPORT, pnetelem->ib_port))
                return -1;
        return 0;
}

/* Retrieve one PNETID entry */
static int smc_pnet_get(struct sk_buff *skb, struct genl_info *info)
{
        struct smc_pnetentry *pnetelem;
        struct sk_buff *msg;
        void *hdr;
        int rc;

        if (!info->attrs[SMC_PNETID_NAME])
                return -EINVAL;
        pnetelem = smc_pnet_find_pnetid(
                                (char *)nla_data(info->attrs[SMC_PNETID_NAME]));
        if (!pnetelem)
                return -ENOENT;
        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq,
                          &smc_pnet_nl_family, 0, SMC_PNETID_GET);
        if (!hdr) {
                rc = -EMSGSIZE;
                goto err_out;
        }

        if (smc_pnet_set_nla(msg, pnetelem)) {
                rc = -ENOBUFS;
                goto err_out;
        }

        genlmsg_end(msg, hdr);
        return genlmsg_reply(msg, info);

err_out:
        nlmsg_free(msg);
        return rc;
}

static int smc_pnet_add(struct sk_buff *skb, struct genl_info *info)
{
        struct net *net = genl_info_net(info);
        struct smc_pnetentry *pnetelem;
        int rc;

        pnetelem = kzalloc(sizeof(*pnetelem), GFP_KERNEL);
        if (!pnetelem)
                return -ENOMEM;
        rc = smc_pnet_fill_entry(net, pnetelem, info->attrs);
        if (!rc)
                rc = smc_pnet_enter(pnetelem);
        if (rc) {
                kfree(pnetelem);
                return rc;
        }
        rc = smc_ib_remember_port_attr(pnetelem->smcibdev, pnetelem->ib_port);
        if (rc)
                smc_pnet_remove_by_pnetid(pnetelem->pnet_name);
        return rc;
}

static int smc_pnet_del(struct sk_buff *skb, struct genl_info *info)
{
        if (!info->attrs[SMC_PNETID_NAME])
                return -EINVAL;
        return smc_pnet_remove_by_pnetid(
                                (char *)nla_data(info->attrs[SMC_PNETID_NAME]));
}

static int smc_pnet_dump_start(struct netlink_callback *cb)
{
        cb->args[0] = 0;
        return 0;
}

static int smc_pnet_dumpinfo(struct sk_buff *skb,
                             u32 portid, u32 seq, u32 flags,
                             struct smc_pnetentry *pnetelem)
{
        void *hdr;

        hdr = genlmsg_put(skb, portid, seq, &smc_pnet_nl_family,
                          flags, SMC_PNETID_GET);
        if (!hdr)
                return -ENOMEM;
        if (smc_pnet_set_nla(skb, pnetelem) < 0) {
                genlmsg_cancel(skb, hdr);
                return -EMSGSIZE;
        }
        genlmsg_end(skb, hdr);
        return 0;
}

static int smc_pnet_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct smc_pnetentry *pnetelem;
        int idx = 0;

        read_lock(&smc_pnettable.lock);
        list_for_each_entry(pnetelem, &smc_pnettable.pnetlist, list) {
                if (idx++ < cb->args[0])
                        continue;
                if (smc_pnet_dumpinfo(skb, NETLINK_CB(cb->skb).portid,
                                      cb->nlh->nlmsg_seq, NLM_F_MULTI,
                                      pnetelem)) {
                        --idx;
                        break;
                }
        }
        cb->args[0] = idx;
        read_unlock(&smc_pnettable.lock);
        return skb->len;
}

/* Remove and delete all pnetids from pnet table.
 */
static int smc_pnet_flush(struct sk_buff *skb, struct genl_info *info)
{
        struct smc_pnetentry *pnetelem, *tmp_pe;

        write_lock(&smc_pnettable.lock);
        list_for_each_entry_safe(pnetelem, tmp_pe, &smc_pnettable.pnetlist,
                                 list) {
                list_del(&pnetelem->list);
                dev_put(pnetelem->ndev);
                kfree(pnetelem);
        }
        write_unlock(&smc_pnettable.lock);
        return 0;
}

/* SMC_PNETID generic netlink operation definition */
static const struct genl_ops smc_pnet_ops[] = {
        {
                .cmd = SMC_PNETID_GET,
                .flags = GENL_ADMIN_PERM,
                .policy = smc_pnet_policy,
                .doit = smc_pnet_get,
                .dumpit = smc_pnet_dump,
                .start = smc_pnet_dump_start
        },
        {
                .cmd = SMC_PNETID_ADD,
                .flags = GENL_ADMIN_PERM,
                .policy = smc_pnet_policy,
                .doit = smc_pnet_add
        },
        {
                .cmd = SMC_PNETID_DEL,
                .flags = GENL_ADMIN_PERM,
                .policy = smc_pnet_policy,
                .doit = smc_pnet_del
        },
        {
                .cmd = SMC_PNETID_FLUSH,
                .flags = GENL_ADMIN_PERM,
                .policy = smc_pnet_policy,
                .doit = smc_pnet_flush
        }
};

/* SMC_PNETID family definition */
static struct genl_family smc_pnet_nl_family = {
        .hdrsize = 0,
        .name = SMCR_GENL_FAMILY_NAME,
        .version = SMCR_GENL_FAMILY_VERSION,
        .maxattr = SMC_PNETID_MAX,
        .netnsok = true,
        .module = THIS_MODULE,
        .ops = smc_pnet_ops,
        .n_ops =  ARRAY_SIZE(smc_pnet_ops)
};

static int smc_pnet_netdev_event(struct notifier_block *this,
                                 unsigned long event, void *ptr)
{
        struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);

        switch (event) {
        case NETDEV_REBOOT:
        case NETDEV_UNREGISTER:
                smc_pnet_remove_by_ndev(event_dev);
        default:
                break;
        }
        return NOTIFY_DONE;
}

static struct notifier_block smc_netdev_notifier = {
        .notifier_call = smc_pnet_netdev_event
};

int __init smc_pnet_init(void)
{
        int rc;

        rc = genl_register_family(&smc_pnet_nl_family);
        if (rc)
                return rc;
        rc = register_netdevice_notifier(&smc_netdev_notifier);
        if (rc)
                genl_unregister_family(&smc_pnet_nl_family);
        return rc;
}

void smc_pnet_exit(void)
{
        smc_pnet_flush(NULL, NULL);
        unregister_netdevice_notifier(&smc_netdev_notifier);
        genl_unregister_family(&smc_pnet_nl_family);
}

/* PNET table analysis for a given sock:
 * determine ib_device and port belonging to used internal TCP socket
 * ethernet interface.
 */
void smc_pnet_find_roce_resource(struct sock *sk,
                                 struct smc_ib_device **smcibdev, u8 *ibport)
{
        struct dst_entry *dst = sk_dst_get(sk);
        struct smc_pnetentry *pnetelem;

        *smcibdev = NULL;
        *ibport = 0;

        if (!dst)
                return;
        if (!dst->dev)
                goto out_rel;
        read_lock(&smc_pnettable.lock);
        list_for_each_entry(pnetelem, &smc_pnettable.pnetlist, list) {
                if (dst->dev == pnetelem->ndev) {
                        if (smc_ib_port_active(pnetelem->smcibdev,
                                               pnetelem->ib_port)) {
                                *smcibdev = pnetelem->smcibdev;
                                *ibport = pnetelem->ib_port;
                        }
                        break;
                }
        }
        read_unlock(&smc_pnettable.lock);
out_rel:
        dst_release(dst);
}