// SPDX-License-Identifier: GPL-2.0
/*
 * Portions
 * Copyright (C) 2022-2024 Intel Corporation
 */
#include <linux/ieee80211.h>
#include <linux/export.h>
#include <net/cfg80211.h>
#include "nl80211.h"
#include "core.h"
#include "rdev-ops.h"

/* Default values, timeouts in ms */
#define MESH_TTL                31
#define MESH_DEFAULT_ELEMENT_TTL 31
#define MESH_MAX_RETR           3
#define MESH_RET_T              100
#define MESH_CONF_T             100
#define MESH_HOLD_T             100

#define MESH_PATH_TIMEOUT       5000
#define MESH_RANN_INTERVAL      5000
#define MESH_PATH_TO_ROOT_TIMEOUT      6000
#define MESH_ROOT_INTERVAL     5000
#define MESH_ROOT_CONFIRMATION_INTERVAL 2000
#define MESH_DEFAULT_PLINK_TIMEOUT      1800 /* timeout in seconds */

/*
 * Minimum interval between two consecutive PREQs originated by the same
 * interface
 */
#define MESH_PREQ_MIN_INT       10
#define MESH_PERR_MIN_INT       100
#define MESH_DIAM_TRAVERSAL_TIME 50

#define MESH_RSSI_THRESHOLD     0

/*
 * A path will be refreshed if it is used PATH_REFRESH_TIME milliseconds
 * before timing out.  This way it will remain ACTIVE and no data frames
 * will be unnecessarily held in the pending queue.
 */
#define MESH_PATH_REFRESH_TIME                  1000
#define MESH_MIN_DISCOVERY_TIMEOUT (2 * MESH_DIAM_TRAVERSAL_TIME)

/* Default maximum number of established plinks per interface */
#define MESH_MAX_ESTAB_PLINKS   32

#define MESH_MAX_PREQ_RETRIES   4

#define MESH_SYNC_NEIGHBOR_OFFSET_MAX 50

#define MESH_DEFAULT_BEACON_INTERVAL    1000    /* in 1024 us units (=TUs) */
#define MESH_DEFAULT_DTIM_PERIOD        2
#define MESH_DEFAULT_AWAKE_WINDOW       10      /* in 1024 us units (=TUs) */

const struct mesh_config default_mesh_config = {
        .dot11MeshRetryTimeout = MESH_RET_T,
        .dot11MeshConfirmTimeout = MESH_CONF_T,
        .dot11MeshHoldingTimeout = MESH_HOLD_T,
        .dot11MeshMaxRetries = MESH_MAX_RETR,
        .dot11MeshTTL = MESH_TTL,
        .element_ttl = MESH_DEFAULT_ELEMENT_TTL,
        .auto_open_plinks = true,
        .dot11MeshMaxPeerLinks = MESH_MAX_ESTAB_PLINKS,
        .dot11MeshNbrOffsetMaxNeighbor = MESH_SYNC_NEIGHBOR_OFFSET_MAX,
        .dot11MeshHWMPactivePathTimeout = MESH_PATH_TIMEOUT,
        .dot11MeshHWMPpreqMinInterval = MESH_PREQ_MIN_INT,
        .dot11MeshHWMPperrMinInterval = MESH_PERR_MIN_INT,
        .dot11MeshHWMPnetDiameterTraversalTime = MESH_DIAM_TRAVERSAL_TIME,
        .dot11MeshHWMPmaxPREQretries = MESH_MAX_PREQ_RETRIES,
        .path_refresh_time = MESH_PATH_REFRESH_TIME,
        .min_discovery_timeout = MESH_MIN_DISCOVERY_TIMEOUT,
        .dot11MeshHWMPRannInterval = MESH_RANN_INTERVAL,
        .dot11MeshGateAnnouncementProtocol = false,
        .dot11MeshForwarding = true,
        .rssi_threshold = MESH_RSSI_THRESHOLD,
        .ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED,
        .dot11MeshHWMPactivePathToRootTimeout = MESH_PATH_TO_ROOT_TIMEOUT,
        .dot11MeshHWMProotInterval = MESH_ROOT_INTERVAL,
        .dot11MeshHWMPconfirmationInterval = MESH_ROOT_CONFIRMATION_INTERVAL,
        .power_mode = NL80211_MESH_POWER_ACTIVE,
        .dot11MeshAwakeWindowDuration = MESH_DEFAULT_AWAKE_WINDOW,
        .plink_timeout = MESH_DEFAULT_PLINK_TIMEOUT,
        .dot11MeshNolearn = false,
};

const struct mesh_setup default_mesh_setup = {
        /* cfg80211_join_mesh() will pick a channel if needed */
        .sync_method = IEEE80211_SYNC_METHOD_NEIGHBOR_OFFSET,
        .path_sel_proto = IEEE80211_PATH_PROTOCOL_HWMP,
        .path_metric = IEEE80211_PATH_METRIC_AIRTIME,
        .auth_id = 0, /* open */
        .ie = NULL,
        .ie_len = 0,
        .is_secure = false,
        .user_mpm = false,
        .beacon_interval = MESH_DEFAULT_BEACON_INTERVAL,
        .dtim_period = MESH_DEFAULT_DTIM_PERIOD,
};

int __cfg80211_join_mesh(struct cfg80211_registered_device *rdev,
                         struct net_device *dev,
                         struct mesh_setup *setup,
                         const struct mesh_config *conf)
{
        struct wireless_dev *wdev = dev->ieee80211_ptr;
        int err;

        BUILD_BUG_ON(IEEE80211_MAX_SSID_LEN != IEEE80211_MAX_MESH_ID_LEN);

        lockdep_assert_wiphy(wdev->wiphy);

        if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_MESH_POINT)
                return -EOPNOTSUPP;

        if (!(rdev->wiphy.flags & WIPHY_FLAG_MESH_AUTH) &&
              setup->is_secure)
                return -EOPNOTSUPP;

        if (wdev->u.mesh.id_len)
                return -EALREADY;

        if (!setup->mesh_id_len)
                return -EINVAL;

        if (!rdev->ops->join_mesh)
                return -EOPNOTSUPP;

        if (wdev->links[0].cac_started)
                return -EBUSY;

        if (!setup->chandef.chan) {
                /* if no channel explicitly given, use preset channel */
                setup->chandef = wdev->u.mesh.preset_chandef;
        }

        if (!setup->chandef.chan) {
                /* if we don't have that either, use the first usable channel */
                enum nl80211_band band;

                for (band = 0; band < NUM_NL80211_BANDS; band++) {
                        struct ieee80211_supported_band *sband;
                        struct ieee80211_channel *chan;
                        int i;

                        sband = rdev->wiphy.bands[band];
                        if (!sband)
                                continue;

                        for (i = 0; i < sband->n_channels; i++) {
                                chan = &sband->channels[i];
                                if (chan->flags & (IEEE80211_CHAN_NO_IR |
                                                   IEEE80211_CHAN_DISABLED |
                                                   IEEE80211_CHAN_RADAR))
                                        continue;
                                setup->chandef.chan = chan;
                                break;
                        }

                        if (setup->chandef.chan)
                                break;
                }

                /* no usable channel ... */
                if (!setup->chandef.chan)
                        return -EINVAL;

                setup->chandef.width = NL80211_CHAN_WIDTH_20_NOHT;
                setup->chandef.center_freq1 = setup->chandef.chan->center_freq;
        }

        /*
         * check if basic rates are available otherwise use mandatory rates as
         * basic rates
         */
        if (!setup->basic_rates) {
                struct ieee80211_supported_band *sband =
                                rdev->wiphy.bands[setup->chandef.chan->band];

                if (setup->chandef.chan->band == NL80211_BAND_2GHZ) {
                        int i;

                        /*
                         * Older versions selected the mandatory rates for
                         * 2.4 GHz as well, but were broken in that only
                         * 1 Mbps was regarded as a mandatory rate. Keep
                         * using just 1 Mbps as the default basic rate for
                         * mesh to be interoperable with older versions.
                         */
                        for (i = 0; i < sband->n_bitrates; i++) {
                                if (sband->bitrates[i].bitrate == 10) {
                                        setup->basic_rates = BIT(i);
                                        break;
                                }
                        }
                } else {
                        setup->basic_rates = ieee80211_mandatory_rates(sband);
                }
        }

        err = cfg80211_chandef_dfs_required(&rdev->wiphy,
                                            &setup->chandef,
                                            NL80211_IFTYPE_MESH_POINT);
        if (err < 0)
                return err;
        if (err > 0 && !setup->userspace_handles_dfs)
                return -EINVAL;

        if (!cfg80211_reg_can_beacon(&rdev->wiphy, &setup->chandef,
                                     NL80211_IFTYPE_MESH_POINT))
                return -EINVAL;

        err = rdev_join_mesh(rdev, dev, conf, setup);
        if (!err) {
                memcpy(wdev->u.mesh.id, setup->mesh_id, setup->mesh_id_len);
                wdev->u.mesh.id_len = setup->mesh_id_len;
                wdev->u.mesh.chandef = setup->chandef;
                wdev->u.mesh.beacon_interval = setup->beacon_interval;
        }

        return err;
}

int cfg80211_set_mesh_channel(struct cfg80211_registered_device *rdev,
                              struct wireless_dev *wdev,
                              struct cfg80211_chan_def *chandef)
{
        int err;

        /*
         * Workaround for libertas (only!), it puts the interface
         * into mesh mode but doesn't implement join_mesh. Instead,
         * it is configured via sysfs and then joins the mesh when
         * you set the channel. Note that the libertas mesh isn't
         * compatible with 802.11 mesh.
         */
        if (rdev->ops->libertas_set_mesh_channel) {
                if (chandef->width != NL80211_CHAN_WIDTH_20_NOHT)
                        return -EINVAL;

                if (!netif_running(wdev->netdev))
                        return -ENETDOWN;

                err = rdev_libertas_set_mesh_channel(rdev, wdev->netdev,
                                                     chandef->chan);
                if (!err)
                        wdev->u.mesh.chandef = *chandef;

                return err;
        }

        if (wdev->u.mesh.id_len)
                return -EBUSY;

        wdev->u.mesh.preset_chandef = *chandef;
        return 0;
}

int cfg80211_leave_mesh(struct cfg80211_registered_device *rdev,
                        struct net_device *dev)
{
        struct wireless_dev *wdev = dev->ieee80211_ptr;
        int err;

        lockdep_assert_wiphy(wdev->wiphy);

        if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_MESH_POINT)
                return -EOPNOTSUPP;

        if (!rdev->ops->leave_mesh)
                return -EOPNOTSUPP;

        if (!wdev->u.mesh.id_len)
                return -ENOTCONN;

        err = rdev_leave_mesh(rdev, dev);
        if (!err) {
                wdev->conn_owner_nlportid = 0;
                wdev->u.mesh.id_len = 0;
                wdev->u.mesh.beacon_interval = 0;
                memset(&wdev->u.mesh.chandef, 0,
                       sizeof(wdev->u.mesh.chandef));
                rdev_set_qos_map(rdev, dev, NULL);
                cfg80211_sched_dfs_chan_update(rdev);
        }

        return err;
}