// 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 <net/netns/generic.h>
#include "smc_netns.h"

#include "smc_pnet.h"
#include "smc_ib.h"
#include "smc_ism.h"
#include "smc_core.h"

#define SMC_ASCII_BLANK 32

static struct net_device *pnet_find_base_ndev(struct net_device *ndev);

static struct nla_policy smc_pnet_policy[SMC_PNETID_MAX + 1] = {
        [SMC_PNETID_NAME] = {
                .type = NLA_NUL_STRING,
                .len = SMC_MAX_PNETID_LEN
        },
        [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_user_pnetentry - pnet identifier name entry for/from user
 * @list: List node.
 * @pnet_name: Pnet identifier name
 * @ndev: pointer to network device.
 * @smcibdev: Pointer to IB device.
 * @ib_port: Port of IB device.
 * @smcd_dev: Pointer to smcd device.
 */
struct smc_user_pnetentry {
        struct list_head list;
        char pnet_name[SMC_MAX_PNETID_LEN + 1];
        struct net_device *ndev;
        struct smc_ib_device *smcibdev;
        u8 ib_port;
        struct smcd_dev *smcd_dev;
};

/* pnet entry stored in pnet table */
struct smc_pnetentry {
        struct list_head list;
        char pnet_name[SMC_MAX_PNETID_LEN + 1];
        struct net_device *ndev;
};

/* Check if two given pnetids match */
static bool smc_pnet_match(u8 *pnetid1, u8 *pnetid2)
{
        int i;

        for (i = 0; i < SMC_MAX_PNETID_LEN; i++) {
                if ((pnetid1[i] == 0 || pnetid1[i] == SMC_ASCII_BLANK) &&
                    (pnetid2[i] == 0 || pnetid2[i] == SMC_ASCII_BLANK))
                        break;
                if (pnetid1[i] != pnetid2[i])
                        return false;
        }
        return true;
}

/* Remove a pnetid from the pnet table.
 */
static int smc_pnet_remove_by_pnetid(struct net *net, char *pnet_name)
{
        struct smc_pnetentry *pnetelem, *tmp_pe;
        struct smc_pnettable *pnettable;
        struct smc_ib_device *ibdev;
        struct smcd_dev *smcd_dev;
        struct smc_net *sn;
        int rc = -ENOENT;
        int ibport;

        /* get pnettable for namespace */
        sn = net_generic(net, smc_net_id);
        pnettable = &sn->pnettable;

        /* remove netdevices */
        write_lock(&pnettable->lock);
        list_for_each_entry_safe(pnetelem, tmp_pe, &pnettable->pnetlist,
                                 list) {
                if (!pnet_name ||
                    smc_pnet_match(pnetelem->pnet_name, pnet_name)) {
                        list_del(&pnetelem->list);
                        dev_put(pnetelem->ndev);
                        kfree(pnetelem);
                        rc = 0;
                }
        }
        write_unlock(&pnettable->lock);

        /* if this is not the initial namespace, stop here */
        if (net != &init_net)
                return rc;

        /* remove ib devices */
        spin_lock(&smc_ib_devices.lock);
        list_for_each_entry(ibdev, &smc_ib_devices.list, list) {
                for (ibport = 0; ibport < SMC_MAX_PORTS; ibport++) {
                        if (ibdev->pnetid_by_user[ibport] &&
                            (!pnet_name ||
                             smc_pnet_match(pnet_name,
                                            ibdev->pnetid[ibport]))) {
                                memset(ibdev->pnetid[ibport], 0,
                                       SMC_MAX_PNETID_LEN);
                                ibdev->pnetid_by_user[ibport] = false;
                                rc = 0;
                        }
                }
        }
        spin_unlock(&smc_ib_devices.lock);
        /* remove smcd devices */
        spin_lock(&smcd_dev_list.lock);
        list_for_each_entry(smcd_dev, &smcd_dev_list.list, list) {
                if (smcd_dev->pnetid_by_user &&
                    (!pnet_name ||
                     smc_pnet_match(pnet_name, smcd_dev->pnetid))) {
                        memset(smcd_dev->pnetid, 0, SMC_MAX_PNETID_LEN);
                        smcd_dev->pnetid_by_user = false;
                        rc = 0;
                }
        }
        spin_unlock(&smcd_dev_list.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;
        struct smc_pnettable *pnettable;
        struct net *net = dev_net(ndev);
        struct smc_net *sn;
        int rc = -ENOENT;

        /* get pnettable for namespace */
        sn = net_generic(net, smc_net_id);
        pnettable = &sn->pnettable;

        write_lock(&pnettable->lock);
        list_for_each_entry_safe(pnetelem, tmp_pe, &pnettable->pnetlist, list) {
                if (pnetelem->ndev == ndev) {
                        list_del(&pnetelem->list);
                        dev_put(pnetelem->ndev);
                        kfree(pnetelem);
                        rc = 0;
                        break;
                }
        }
        write_unlock(&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_pnettable *pnettable,
                          struct smc_user_pnetentry *new_pnetelem)
{
        u8 pnet_null[SMC_MAX_PNETID_LEN] = {0};
        u8 ndev_pnetid[SMC_MAX_PNETID_LEN];
        struct smc_pnetentry *tmp_pnetelem;
        struct smc_pnetentry *pnetelem;
        bool new_smcddev = false;
        struct net_device *ndev;
        bool new_netdev = true;
        bool new_ibdev = false;

        if (new_pnetelem->smcibdev) {
                struct smc_ib_device *ib_dev = new_pnetelem->smcibdev;
                int ib_port = new_pnetelem->ib_port;

                spin_lock(&smc_ib_devices.lock);
                if (smc_pnet_match(ib_dev->pnetid[ib_port - 1], pnet_null)) {
                        memcpy(ib_dev->pnetid[ib_port - 1],
                               new_pnetelem->pnet_name, SMC_MAX_PNETID_LEN);
                        ib_dev->pnetid_by_user[ib_port - 1] = true;
                        new_ibdev = true;
                }
                spin_unlock(&smc_ib_devices.lock);
        }
        if (new_pnetelem->smcd_dev) {
                struct smcd_dev *smcd_dev = new_pnetelem->smcd_dev;

                spin_lock(&smcd_dev_list.lock);
                if (smc_pnet_match(smcd_dev->pnetid, pnet_null)) {
                        memcpy(smcd_dev->pnetid, new_pnetelem->pnet_name,
                               SMC_MAX_PNETID_LEN);
                        smcd_dev->pnetid_by_user = true;
                        new_smcddev = true;
                }
                spin_unlock(&smcd_dev_list.lock);
        }

        if (!new_pnetelem->ndev)
                return (new_ibdev || new_smcddev) ? 0 : -EEXIST;

        /* check if (base) netdev already has a pnetid. If there is one, we do
         * not want to add a pnet table entry
         */
        ndev = pnet_find_base_ndev(new_pnetelem->ndev);
        if (!smc_pnetid_by_dev_port(ndev->dev.parent, ndev->dev_port,
                                    ndev_pnetid))
                return (new_ibdev || new_smcddev) ? 0 : -EEXIST;

        /* add a new netdev entry to the pnet table if there isn't one */
        tmp_pnetelem = kzalloc(sizeof(*pnetelem), GFP_KERNEL);
        if (!tmp_pnetelem)
                return -ENOMEM;
        memcpy(tmp_pnetelem->pnet_name, new_pnetelem->pnet_name,
               SMC_MAX_PNETID_LEN);
        tmp_pnetelem->ndev = new_pnetelem->ndev;

        write_lock(&pnettable->lock);
        list_for_each_entry(pnetelem, &pnettable->pnetlist, list) {
                if (pnetelem->ndev == new_pnetelem->ndev)
                        new_netdev = false;
        }
        if (new_netdev) {
                dev_hold(tmp_pnetelem->ndev);
                list_add_tail(&tmp_pnetelem->list, &pnettable->pnetlist);
                write_unlock(&pnettable->lock);
        } else {
                write_unlock(&pnettable->lock);
                kfree(tmp_pnetelem);
        }

        return (new_netdev || new_ibdev || new_smcddev) ? 0 : -EEXIST;
}

/* 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_PNETID_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)) ||
                    !strncmp(dev_name(ibdev->ibdev->dev.parent), ib_name,
                             IB_DEVICE_NAME_MAX - 1)) {
                        goto out;
                }
        }
        ibdev = NULL;
out:
        spin_unlock(&smc_ib_devices.lock);
        return ibdev;
}

/* Find an smcd device by a given name. The device might not exist. */
static struct smcd_dev *smc_pnet_find_smcd(char *smcd_name)
{
        struct smcd_dev *smcd_dev;

        spin_lock(&smcd_dev_list.lock);
        list_for_each_entry(smcd_dev, &smcd_dev_list.list, list) {
                if (!strncmp(dev_name(&smcd_dev->dev), smcd_name,
                             IB_DEVICE_NAME_MAX - 1))
                        goto out;
        }
        smcd_dev = NULL;
out:
        spin_unlock(&smcd_dev_list.lock);
        return smcd_dev;
}

/* 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_user_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]) {
                string = (char *)nla_data(tb[SMC_PNETID_ETHNAME]);
                pnetelem->ndev = dev_get_by_name(net, string);
                if (!pnetelem->ndev)
                        goto error;
        }

        /* if this is not the initial namespace, stop here */
        if (net != &init_net)
                return 0;

        rc = -EINVAL;
        if (tb[SMC_PNETID_IBNAME]) {
                ibname = (char *)nla_data(tb[SMC_PNETID_IBNAME]);
                ibname = strim(ibname);
                pnetelem->smcibdev = smc_pnet_find_ib(ibname);
                pnetelem->smcd_dev = smc_pnet_find_smcd(ibname);
                if (!pnetelem->smcibdev && !pnetelem->smcd_dev)
                        goto error;
                if (pnetelem->smcibdev) {
                        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_user_pnetentry *pnetelem)
{
        if (nla_put_string(msg, SMC_PNETID_NAME, pnetelem->pnet_name))
                return -1;
        if (pnetelem->ndev) {
                if (nla_put_string(msg, SMC_PNETID_ETHNAME,
                                   pnetelem->ndev->name))
                        return -1;
        } else {
                if (nla_put_string(msg, SMC_PNETID_ETHNAME, "n/a"))
                        return -1;
        }
        if (pnetelem->smcibdev) {
                if (nla_put_string(msg, SMC_PNETID_IBNAME,
                        dev_name(pnetelem->smcibdev->ibdev->dev.parent)) ||
                    nla_put_u8(msg, SMC_PNETID_IBPORT, pnetelem->ib_port))
                        return -1;
        } else if (pnetelem->smcd_dev) {
                if (nla_put_string(msg, SMC_PNETID_IBNAME,
                                   dev_name(&pnetelem->smcd_dev->dev)) ||
                    nla_put_u8(msg, SMC_PNETID_IBPORT, 1))
                        return -1;
        } else {
                if (nla_put_string(msg, SMC_PNETID_IBNAME, "n/a") ||
                    nla_put_u8(msg, SMC_PNETID_IBPORT, 0xff))
                        return -1;
        }

        return 0;
}

static int smc_pnet_add(struct sk_buff *skb, struct genl_info *info)
{
        struct net *net = genl_info_net(info);
        struct smc_user_pnetentry pnetelem;
        struct smc_pnettable *pnettable;
        struct smc_net *sn;
        int rc;

        /* get pnettable for namespace */
        sn = net_generic(net, smc_net_id);
        pnettable = &sn->pnettable;

        rc = smc_pnet_fill_entry(net, &pnetelem, info->attrs);
        if (!rc)
                rc = smc_pnet_enter(pnettable, &pnetelem);
        if (pnetelem.ndev)
                dev_put(pnetelem.ndev);
        return rc;
}

static int smc_pnet_del(struct sk_buff *skb, struct genl_info *info)
{
        struct net *net = genl_info_net(info);

        if (!info->attrs[SMC_PNETID_NAME])
                return -EINVAL;
        return smc_pnet_remove_by_pnetid(net,
                                (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_user_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 net *net, struct sk_buff *skb, u32 portid,
                          u32 seq, u8 *pnetid, int start_idx)
{
        struct smc_user_pnetentry tmp_entry;
        struct smc_pnettable *pnettable;
        struct smc_pnetentry *pnetelem;
        struct smc_ib_device *ibdev;
        struct smcd_dev *smcd_dev;
        struct smc_net *sn;
        int idx = 0;
        int ibport;

        /* get pnettable for namespace */
        sn = net_generic(net, smc_net_id);
        pnettable = &sn->pnettable;

        /* dump netdevices */
        read_lock(&pnettable->lock);
        list_for_each_entry(pnetelem, &pnettable->pnetlist, list) {
                if (pnetid && !smc_pnet_match(pnetelem->pnet_name, pnetid))
                        continue;
                if (idx++ < start_idx)
                        continue;
                memset(&tmp_entry, 0, sizeof(tmp_entry));
                memcpy(&tmp_entry.pnet_name, pnetelem->pnet_name,
                       SMC_MAX_PNETID_LEN);
                tmp_entry.ndev = pnetelem->ndev;
                if (smc_pnet_dumpinfo(skb, portid, seq, NLM_F_MULTI,
                                      &tmp_entry)) {
                        --idx;
                        break;
                }
        }
        read_unlock(&pnettable->lock);

        /* if this is not the initial namespace, stop here */
        if (net != &init_net)
                return idx;

        /* dump ib devices */
        spin_lock(&smc_ib_devices.lock);
        list_for_each_entry(ibdev, &smc_ib_devices.list, list) {
                for (ibport = 0; ibport < SMC_MAX_PORTS; ibport++) {
                        if (ibdev->pnetid_by_user[ibport]) {
                                if (pnetid &&
                                    !smc_pnet_match(ibdev->pnetid[ibport],
                                                    pnetid))
                                        continue;
                                if (idx++ < start_idx)
                                        continue;
                                memset(&tmp_entry, 0, sizeof(tmp_entry));
                                memcpy(&tmp_entry.pnet_name,
                                       ibdev->pnetid[ibport],
                                       SMC_MAX_PNETID_LEN);
                                tmp_entry.smcibdev = ibdev;
                                tmp_entry.ib_port = ibport + 1;
                                if (smc_pnet_dumpinfo(skb, portid, seq,
                                                      NLM_F_MULTI,
                                                      &tmp_entry)) {
                                        --idx;
                                        break;
                                }
                        }
                }
        }
        spin_unlock(&smc_ib_devices.lock);

        /* dump smcd devices */
        spin_lock(&smcd_dev_list.lock);
        list_for_each_entry(smcd_dev, &smcd_dev_list.list, list) {
                if (smcd_dev->pnetid_by_user) {
                        if (pnetid && !smc_pnet_match(smcd_dev->pnetid, pnetid))
                                continue;
                        if (idx++ < start_idx)
                                continue;
                        memset(&tmp_entry, 0, sizeof(tmp_entry));
                        memcpy(&tmp_entry.pnet_name, smcd_dev->pnetid,
                               SMC_MAX_PNETID_LEN);
                        tmp_entry.smcd_dev = smcd_dev;
                        if (smc_pnet_dumpinfo(skb, portid, seq, NLM_F_MULTI,
                                              &tmp_entry)) {
                                --idx;
                                break;
                        }
                }
        }
        spin_unlock(&smcd_dev_list.lock);

        return idx;
}

static int smc_pnet_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
        struct net *net = sock_net(skb->sk);
        int idx;

        idx = _smc_pnet_dump(net, skb, NETLINK_CB(cb->skb).portid,
                             cb->nlh->nlmsg_seq, NULL, cb->args[0]);

        cb->args[0] = idx;
        return skb->len;
}

/* Retrieve one PNETID entry */
static int smc_pnet_get(struct sk_buff *skb, struct genl_info *info)
{
        struct net *net = genl_info_net(info);
        struct sk_buff *msg;
        void *hdr;

        if (!info->attrs[SMC_PNETID_NAME])
                return -EINVAL;

        msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        _smc_pnet_dump(net, msg, info->snd_portid, info->snd_seq,
                       nla_data(info->attrs[SMC_PNETID_NAME]), 0);

        /* finish multi part message and send it */
        hdr = nlmsg_put(msg, info->snd_portid, info->snd_seq, NLMSG_DONE, 0,
                        NLM_F_MULTI);
        if (!hdr) {
                nlmsg_free(msg);
                return -EMSGSIZE;
        }
        return genlmsg_reply(msg, info);
}

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

        smc_pnet_remove_by_pnetid(net, NULL);
        return 0;
}

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

/* SMC_PNETID family definition */
static struct genl_family smc_pnet_nl_family __ro_after_init = {
        .hdrsize = 0,
        .name = SMCR_GENL_FAMILY_NAME,
        .version = SMCR_GENL_FAMILY_VERSION,
        .maxattr = SMC_PNETID_MAX,
        .policy = smc_pnet_policy,
        .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);
                return NOTIFY_OK;
        default:
                return NOTIFY_DONE;
        }
}

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

/* init network namespace */
int smc_pnet_net_init(struct net *net)
{
        struct smc_net *sn = net_generic(net, smc_net_id);
        struct smc_pnettable *pnettable = &sn->pnettable;

        INIT_LIST_HEAD(&pnettable->pnetlist);
        rwlock_init(&pnettable->lock);

        return 0;
}

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;
}

/* exit network namespace */
void smc_pnet_net_exit(struct net *net)
{
        /* flush pnet table */
        smc_pnet_remove_by_pnetid(net, NULL);
}

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

/* Determine one base device for stacked net devices.
 * If the lower device level contains more than one devices
 * (for instance with bonding slaves), just the first device
 * is used to reach a base device.
 */
static struct net_device *pnet_find_base_ndev(struct net_device *ndev)
{
        int i, nest_lvl;

        rtnl_lock();
        nest_lvl = dev_get_nest_level(ndev);
        for (i = 0; i < nest_lvl; i++) {
                struct list_head *lower = &ndev->adj_list.lower;

                if (list_empty(lower))
                        break;
                lower = lower->next;
                ndev = netdev_lower_get_next(ndev, &lower);
        }
        rtnl_unlock();
        return ndev;
}

static int smc_pnet_find_ndev_pnetid_by_table(struct net_device *ndev,
                                              u8 *pnetid)
{
        struct smc_pnettable *pnettable;
        struct net *net = dev_net(ndev);
        struct smc_pnetentry *pnetelem;
        struct smc_net *sn;
        int rc = -ENOENT;

        /* get pnettable for namespace */
        sn = net_generic(net, smc_net_id);
        pnettable = &sn->pnettable;

        read_lock(&pnettable->lock);
        list_for_each_entry(pnetelem, &pnettable->pnetlist, list) {
                if (ndev == pnetelem->ndev) {
                        /* get pnetid of netdev device */
                        memcpy(pnetid, pnetelem->pnet_name, SMC_MAX_PNETID_LEN);
                        rc = 0;
                        break;
                }
        }
        read_unlock(&pnettable->lock);
        return rc;
}

/* if handshake network device belongs to a roce device, return its
 * IB device and port
 */
static void smc_pnet_find_rdma_dev(struct net_device *netdev,
                                   struct smc_init_info *ini)
{
        struct smc_ib_device *ibdev;

        spin_lock(&smc_ib_devices.lock);
        list_for_each_entry(ibdev, &smc_ib_devices.list, list) {
                struct net_device *ndev;
                int i;

                for (i = 1; i <= SMC_MAX_PORTS; i++) {
                        if (!rdma_is_port_valid(ibdev->ibdev, i))
                                continue;
                        if (!ibdev->ibdev->ops.get_netdev)
                                continue;
                        ndev = ibdev->ibdev->ops.get_netdev(ibdev->ibdev, i);
                        if (!ndev)
                                continue;
                        dev_put(ndev);
                        if (netdev == ndev &&
                            smc_ib_port_active(ibdev, i) &&
                            !smc_ib_determine_gid(ibdev, i, ini->vlan_id,
                                                  ini->ib_gid, NULL)) {
                                ini->ib_dev = ibdev;
                                ini->ib_port = i;
                                break;
                        }
                }
        }
        spin_unlock(&smc_ib_devices.lock);
}

/* Determine the corresponding IB device port based on the hardware PNETID.
 * Searching stops at the first matching active IB device port with vlan_id
 * configured.
 * If nothing found, check pnetid table.
 * If nothing found, try to use handshake device
 */
static void smc_pnet_find_roce_by_pnetid(struct net_device *ndev,
                                         struct smc_init_info *ini)
{
        u8 ndev_pnetid[SMC_MAX_PNETID_LEN];
        struct smc_ib_device *ibdev;
        int i;

        ndev = pnet_find_base_ndev(ndev);
        if (smc_pnetid_by_dev_port(ndev->dev.parent, ndev->dev_port,
                                   ndev_pnetid) &&
            smc_pnet_find_ndev_pnetid_by_table(ndev, ndev_pnetid)) {
                smc_pnet_find_rdma_dev(ndev, ini);
                return; /* pnetid could not be determined */
        }

        spin_lock(&smc_ib_devices.lock);
        list_for_each_entry(ibdev, &smc_ib_devices.list, list) {
                for (i = 1; i <= SMC_MAX_PORTS; i++) {
                        if (!rdma_is_port_valid(ibdev->ibdev, i))
                                continue;
                        if (smc_pnet_match(ibdev->pnetid[i - 1], ndev_pnetid) &&
                            smc_ib_port_active(ibdev, i) &&
                            !smc_ib_determine_gid(ibdev, i, ini->vlan_id,
                                                  ini->ib_gid, NULL)) {
                                ini->ib_dev = ibdev;
                                ini->ib_port = i;
                                goto out;
                        }
                }
        }
out:
        spin_unlock(&smc_ib_devices.lock);
}

static void smc_pnet_find_ism_by_pnetid(struct net_device *ndev,
                                        struct smc_init_info *ini)
{
        u8 ndev_pnetid[SMC_MAX_PNETID_LEN];
        struct smcd_dev *ismdev;

        ndev = pnet_find_base_ndev(ndev);
        if (smc_pnetid_by_dev_port(ndev->dev.parent, ndev->dev_port,
                                   ndev_pnetid) &&
            smc_pnet_find_ndev_pnetid_by_table(ndev, ndev_pnetid))
                return; /* pnetid could not be determined */

        spin_lock(&smcd_dev_list.lock);
        list_for_each_entry(ismdev, &smcd_dev_list.list, list) {
                if (smc_pnet_match(ismdev->pnetid, ndev_pnetid)) {
                        ini->ism_dev = ismdev;
                        break;
                }
        }
        spin_unlock(&smcd_dev_list.lock);
}

/* 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_init_info *ini)
{
        struct dst_entry *dst = sk_dst_get(sk);

        ini->ib_dev = NULL;
        ini->ib_port = 0;
        if (!dst)
                goto out;
        if (!dst->dev)
                goto out_rel;

        smc_pnet_find_roce_by_pnetid(dst->dev, ini);

out_rel:
        dst_release(dst);
out:
        return;
}

void smc_pnet_find_ism_resource(struct sock *sk, struct smc_init_info *ini)
{
        struct dst_entry *dst = sk_dst_get(sk);

        ini->ism_dev = NULL;
        if (!dst)
                goto out;
        if (!dst->dev)
                goto out_rel;

        smc_pnet_find_ism_by_pnetid(dst->dev, ini);

out_rel:
        dst_release(dst);
out:
        return;
}