net/mac80211/link.c

root/net/mac80211/link.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * MLO link handling
 *
 * Copyright (C) 2022-2025 Intel Corporation
 */
#include <linux/slab.h>
#include <linux/kernel.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"
#include "key.h"
#include "debugfs_netdev.h"

static void ieee80211_update_apvlan_links(struct ieee80211_sub_if_data *sdata)
{
        struct ieee80211_sub_if_data *vlan;
        struct ieee80211_link_data *link;
        u16 ap_bss_links = sdata->vif.valid_links;
        u16 new_links, vlan_links;
        unsigned long add;

        list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) {
                int link_id;

                /* No support for 4addr with MLO yet */
                if (vlan->wdev.use_4addr)
                        return;

                vlan_links = vlan->vif.valid_links;

                new_links = ap_bss_links;

                add = new_links & ~vlan_links;
                if (!add)
                        continue;

                ieee80211_vif_set_links(vlan, add, 0);

                for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
                        link = sdata_dereference(vlan->link[link_id], vlan);
                        ieee80211_link_vlan_copy_chanctx(link);
                }
        }
}

void ieee80211_apvlan_link_setup(struct ieee80211_sub_if_data *sdata)
{
        struct ieee80211_sub_if_data *ap_bss = container_of(sdata->bss,
                                            struct ieee80211_sub_if_data, u.ap);
        u16 new_links = ap_bss->vif.valid_links;
        unsigned long add;
        int link_id;

        if (!ap_bss->vif.valid_links)
                return;

        add = new_links;
        for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
                sdata->wdev.valid_links |= BIT(link_id);
                ether_addr_copy(sdata->wdev.links[link_id].addr,
                                ap_bss->wdev.links[link_id].addr);
        }

        ieee80211_vif_set_links(sdata, new_links, 0);
}

void ieee80211_apvlan_link_clear(struct ieee80211_sub_if_data *sdata)
{
        if (!sdata->wdev.valid_links)
                return;

        sdata->wdev.valid_links = 0;
        ieee80211_vif_clear_links(sdata);
}

void ieee80211_link_setup(struct ieee80211_link_data *link)
{
        if (link->sdata->vif.type == NL80211_IFTYPE_STATION)
                ieee80211_mgd_setup_link(link);
}

void ieee80211_link_init(struct ieee80211_sub_if_data *sdata,
                         int link_id,
                         struct ieee80211_link_data *link,
                         struct ieee80211_bss_conf *link_conf)
{
        bool deflink = link_id < 0;

        if (link_id < 0)
                link_id = 0;

        if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
                struct ieee80211_sub_if_data *ap_bss;
                struct ieee80211_bss_conf *ap_bss_conf;

                ap_bss = container_of(sdata->bss,
                                      struct ieee80211_sub_if_data, u.ap);
                ap_bss_conf = sdata_dereference(ap_bss->vif.link_conf[link_id],
                                                ap_bss);
                memcpy(link_conf, ap_bss_conf, sizeof(*link_conf));
        }

        link->sdata = sdata;
        link->link_id = link_id;
        link->conf = link_conf;
        link_conf->link_id = link_id;
        link_conf->vif = &sdata->vif;
        link->ap_power_level = IEEE80211_UNSET_POWER_LEVEL;
        link->user_power_level = sdata->local->user_power_level;
        link_conf->txpower = INT_MIN;

        wiphy_work_init(&link->csa.finalize_work,
                        ieee80211_csa_finalize_work);
        wiphy_work_init(&link->color_change_finalize_work,
                        ieee80211_color_change_finalize_work);
        wiphy_delayed_work_init(&link->color_collision_detect_work,
                                ieee80211_color_collision_detection_work);
        wiphy_hrtimer_work_init(&link->dfs_cac_timer_work,
                                ieee80211_dfs_cac_timer_work);

        if (!deflink) {
                switch (sdata->vif.type) {
                case NL80211_IFTYPE_AP:
                case NL80211_IFTYPE_AP_VLAN:
                        ether_addr_copy(link_conf->addr,
                                        sdata->wdev.links[link_id].addr);
                        link_conf->bssid = link_conf->addr;
                        WARN_ON(!(sdata->wdev.valid_links & BIT(link_id)));
                        break;
                case NL80211_IFTYPE_STATION:
                        /* station sets the bssid in ieee80211_mgd_setup_link */
                        break;
                default:
                        WARN_ON(1);
                }

                ieee80211_link_debugfs_add(link);
        }

        rcu_assign_pointer(sdata->vif.link_conf[link_id], link_conf);
        rcu_assign_pointer(sdata->link[link_id], link);
}

void ieee80211_link_stop(struct ieee80211_link_data *link)
{
        if (link->sdata->vif.type == NL80211_IFTYPE_STATION)
                ieee80211_mgd_stop_link(link);

        wiphy_delayed_work_cancel(link->sdata->local->hw.wiphy,
                                  &link->color_collision_detect_work);
        wiphy_work_cancel(link->sdata->local->hw.wiphy,
                          &link->color_change_finalize_work);
        wiphy_work_cancel(link->sdata->local->hw.wiphy,
                          &link->csa.finalize_work);

        if (link->sdata->wdev.links[link->link_id].cac_started) {
                wiphy_hrtimer_work_cancel(link->sdata->local->hw.wiphy,
                                          &link->dfs_cac_timer_work);
                cfg80211_cac_event(link->sdata->dev,
                                   &link->conf->chanreq.oper,
                                   NL80211_RADAR_CAC_ABORTED,
                                   GFP_KERNEL, link->link_id);
        }

        ieee80211_link_release_channel(link);
}

struct link_container {
        struct ieee80211_link_data data;
        struct ieee80211_bss_conf conf;
};

static void ieee80211_tear_down_links(struct ieee80211_sub_if_data *sdata,
                                      struct link_container **links, u16 mask)
{
        struct ieee80211_link_data *link;
        LIST_HEAD(keys);
        unsigned int link_id;

        for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++) {
                if (!(mask & BIT(link_id)))
                        continue;
                link = &links[link_id]->data;
                if (link_id == 0 && !link)
                        link = &sdata->deflink;
                if (WARN_ON(!link))
                        continue;
                ieee80211_remove_link_keys(link, &keys);
                ieee80211_link_debugfs_remove(link);
                ieee80211_link_stop(link);
        }

        synchronize_rcu();

        ieee80211_free_key_list(sdata->local, &keys);
}

static void ieee80211_free_links(struct ieee80211_sub_if_data *sdata,
                                 struct link_container **links)
{
        unsigned int link_id;

        for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++)
                kfree(links[link_id]);
}

static int ieee80211_check_dup_link_addrs(struct ieee80211_sub_if_data *sdata)
{
        unsigned int i, j;

        for (i = 0; i < IEEE80211_MLD_MAX_NUM_LINKS; i++) {
                struct ieee80211_link_data *link1;

                link1 = sdata_dereference(sdata->link[i], sdata);
                if (!link1)
                        continue;
                for (j = i + 1; j < IEEE80211_MLD_MAX_NUM_LINKS; j++) {
                        struct ieee80211_link_data *link2;

                        link2 = sdata_dereference(sdata->link[j], sdata);
                        if (!link2)
                                continue;

                        if (ether_addr_equal(link1->conf->addr,
                                             link2->conf->addr))
                                return -EALREADY;
                }
        }

        return 0;
}

static void ieee80211_set_vif_links_bitmaps(struct ieee80211_sub_if_data *sdata,
                                            u16 valid_links, u16 dormant_links)
{
        sdata->vif.valid_links = valid_links;
        sdata->vif.dormant_links = dormant_links;

        if (!valid_links ||
            WARN((~valid_links & dormant_links) ||
                 !(valid_links & ~dormant_links),
                 "Invalid links: valid=0x%x, dormant=0x%x",
                 valid_links, dormant_links)) {
                sdata->vif.active_links = 0;
                sdata->vif.dormant_links = 0;
                return;
        }

        switch (sdata->vif.type) {
        case NL80211_IFTYPE_AP:
        case NL80211_IFTYPE_AP_VLAN:
                /* in an AP all links are always active */
                sdata->vif.active_links = valid_links;

                /* AP links are not expected to be disabled */
                WARN_ON(dormant_links);
                break;
        case NL80211_IFTYPE_STATION:
                if (sdata->vif.active_links)
                        break;
                sdata->vif.active_links = valid_links & ~dormant_links;
                WARN_ON(hweight16(sdata->vif.active_links) > 1);
                break;
        default:
                WARN_ON(1);
        }
}

static int ieee80211_vif_update_links(struct ieee80211_sub_if_data *sdata,
                                      struct link_container **to_free,
                                      u16 new_links, u16 dormant_links)
{
        u16 old_links = sdata->vif.valid_links;
        u16 old_active = sdata->vif.active_links;
        unsigned long add = new_links & ~old_links;
        unsigned long rem = old_links & ~new_links;
        unsigned int link_id;
        int ret;
        struct link_container *links[IEEE80211_MLD_MAX_NUM_LINKS] = {}, *link;
        struct ieee80211_bss_conf *old[IEEE80211_MLD_MAX_NUM_LINKS];
        struct ieee80211_link_data *old_data[IEEE80211_MLD_MAX_NUM_LINKS];
        bool use_deflink = old_links == 0; /* set for error case */
        bool non_sta = sdata->vif.type != NL80211_IFTYPE_STATION;

        lockdep_assert_wiphy(sdata->local->hw.wiphy);

        memset(to_free, 0, sizeof(links));

        if (old_links == new_links && dormant_links == sdata->vif.dormant_links)
                return 0;

        /* if there were no old links, need to clear the pointers to deflink */
        if (!old_links)
                rem |= BIT(0);

        /* allocate new link structures first */
        for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
                link = kzalloc_obj(*link);
                if (!link) {
                        ret = -ENOMEM;
                        goto free;
                }
                links[link_id] = link;
        }

        /* keep track of the old pointers for the driver */
        BUILD_BUG_ON(sizeof(old) != sizeof(sdata->vif.link_conf));
        memcpy(old, sdata->vif.link_conf, sizeof(old));
        /* and for us in error cases */
        BUILD_BUG_ON(sizeof(old_data) != sizeof(sdata->link));
        memcpy(old_data, sdata->link, sizeof(old_data));

        /* grab old links to free later */
        for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
                if (rcu_access_pointer(sdata->link[link_id]) != &sdata->deflink) {
                        /*
                         * we must have allocated the data through this path so
                         * we know we can free both at the same time
                         */
                        to_free[link_id] = container_of(rcu_access_pointer(sdata->link[link_id]),
                                                        typeof(*links[link_id]),
                                                        data);
                }

                RCU_INIT_POINTER(sdata->link[link_id], NULL);
                RCU_INIT_POINTER(sdata->vif.link_conf[link_id], NULL);
        }

        if (!old_links)
                ieee80211_debugfs_recreate_netdev(sdata, true);

        /* link them into data structures */
        for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
                WARN_ON(!use_deflink &&
                        rcu_access_pointer(sdata->link[link_id]) == &sdata->deflink);

                link = links[link_id];
                ieee80211_link_init(sdata, link_id, &link->data, &link->conf);
                ieee80211_link_setup(&link->data);
                ieee80211_set_wmm_default(&link->data, true, non_sta);
        }

        if (new_links == 0)
                ieee80211_link_init(sdata, -1, &sdata->deflink,
                                    &sdata->vif.bss_conf);

        ret = ieee80211_check_dup_link_addrs(sdata);
        if (!ret) {
                /* for keys we will not be able to undo this */
                ieee80211_tear_down_links(sdata, to_free, rem);

                ieee80211_set_vif_links_bitmaps(sdata, new_links, dormant_links);

                /* tell the driver */
                if (sdata->vif.type != NL80211_IFTYPE_AP_VLAN)
                        ret = drv_change_vif_links(sdata->local, sdata,
                                                   old_links & old_active,
                                                   new_links & sdata->vif.active_links,
                                                   old);
                if (!new_links)
                        ieee80211_debugfs_recreate_netdev(sdata, false);

                if (sdata->vif.type == NL80211_IFTYPE_AP)
                        ieee80211_update_apvlan_links(sdata);
        }

        /*
         * Ignore errors if we are only removing links as removal should
         * always succeed
         */
        if (!new_links)
                ret = 0;

        if (ret) {
                /* restore config */
                memcpy(sdata->link, old_data, sizeof(old_data));
                memcpy(sdata->vif.link_conf, old, sizeof(old));
                ieee80211_set_vif_links_bitmaps(sdata, old_links, dormant_links);
                /* and free (only) the newly allocated links */
                memset(to_free, 0, sizeof(links));
                goto free;
        }

        /* use deflink/bss_conf again if and only if there are no more links */
        use_deflink = new_links == 0;

        goto deinit;
free:
        /* if we failed during allocation, only free all */
        for (link_id = 0; link_id < IEEE80211_MLD_MAX_NUM_LINKS; link_id++) {
                kfree(links[link_id]);
                links[link_id] = NULL;
        }
deinit:
        if (use_deflink)
                ieee80211_link_init(sdata, -1, &sdata->deflink,
                                    &sdata->vif.bss_conf);
        return ret;
}

int ieee80211_vif_set_links(struct ieee80211_sub_if_data *sdata,
                            u16 new_links, u16 dormant_links)
{
        struct link_container *links[IEEE80211_MLD_MAX_NUM_LINKS];
        int ret;

        ret = ieee80211_vif_update_links(sdata, links, new_links,
                                         dormant_links);
        ieee80211_free_links(sdata, links);

        return ret;
}

static int _ieee80211_set_active_links(struct ieee80211_sub_if_data *sdata,
                                       u16 active_links)
{
        struct ieee80211_bss_conf *link_confs[IEEE80211_MLD_MAX_NUM_LINKS];
        struct ieee80211_local *local = sdata->local;
        u16 old_active = sdata->vif.active_links;
        unsigned long rem = old_active & ~active_links;
        unsigned long add = active_links & ~old_active;
        struct sta_info *sta;
        unsigned int link_id;
        int ret, i;

        if (!ieee80211_sdata_running(sdata))
                return -ENETDOWN;

        if (sdata->vif.type != NL80211_IFTYPE_STATION)
                return -EINVAL;

        if (active_links & ~ieee80211_vif_usable_links(&sdata->vif))
                return -EINVAL;

        /* nothing to do */
        if (old_active == active_links)
                return 0;

        for (i = 0; i < IEEE80211_MLD_MAX_NUM_LINKS; i++)
                link_confs[i] = sdata_dereference(sdata->vif.link_conf[i],
                                                  sdata);

        if (add) {
                sdata->vif.active_links |= active_links;
                ret = drv_change_vif_links(local, sdata,
                                           old_active,
                                           sdata->vif.active_links,
                                           link_confs);
                if (ret) {
                        sdata->vif.active_links = old_active;
                        return ret;
                }
        }

        for_each_set_bit(link_id, &rem, IEEE80211_MLD_MAX_NUM_LINKS) {
                struct ieee80211_link_data *link;

                link = sdata_dereference(sdata->link[link_id], sdata);

                ieee80211_teardown_tdls_peers(link);

                __ieee80211_link_release_channel(link, true);

                /*
                 * If CSA is (still) active while the link is deactivated,
                 * just schedule the channel switch work for the time we
                 * had previously calculated, and we'll take the process
                 * from there.
                 */
                if (link->conf->csa_active)
                        wiphy_hrtimer_work_queue(local->hw.wiphy,
                                                 &link->u.mgd.csa.switch_work,
                                                 link->u.mgd.csa.time -
                                                 ktime_get_boottime());
        }

        for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
                struct ieee80211_link_data *link;

                link = sdata_dereference(sdata->link[link_id], sdata);

                /*
                 * This call really should not fail. Unfortunately, it appears
                 * that this may happen occasionally with some drivers. Should
                 * it happen, we are stuck in a bad place as going backwards is
                 * not really feasible.
                 *
                 * So lets just tell link_use_channel that it must not fail to
                 * assign the channel context (from mac80211's perspective) and
                 * assume the driver is going to trigger a recovery flow if it
                 * had a failure.
                 * That really is not great nor guaranteed to work. But at least
                 * the internal mac80211 state remains consistent and there is
                 * a chance that we can recover.
                 */
                ret = _ieee80211_link_use_channel(link,
                                                  &link->conf->chanreq,
                                                  IEEE80211_CHANCTX_SHARED,
                                                  true);
                WARN_ON_ONCE(ret);

                /*
                 * inform about the link info changed parameters after all
                 * stations are also added
                 */
        }

        list_for_each_entry(sta, &local->sta_list, list) {
                if (sdata != sta->sdata)
                        continue;

                /* this is very temporary, but do it anyway */
                __ieee80211_sta_recalc_aggregates(sta,
                                                  old_active | active_links);

                ret = drv_change_sta_links(local, sdata, &sta->sta,
                                           old_active,
                                           old_active | active_links);
                WARN_ON_ONCE(ret);
        }

        ret = ieee80211_key_switch_links(sdata, rem, add);
        WARN_ON_ONCE(ret);

        list_for_each_entry(sta, &local->sta_list, list) {
                if (sdata != sta->sdata)
                        continue;

                __ieee80211_sta_recalc_aggregates(sta, active_links);

                ret = drv_change_sta_links(local, sdata, &sta->sta,
                                           old_active | active_links,
                                           active_links);
                WARN_ON_ONCE(ret);

                /*
                 * Do it again, just in case - the driver might very
                 * well have called ieee80211_sta_recalc_aggregates()
                 * from there when filling in the new links, which
                 * would set it wrong since the vif's active links are
                 * not switched yet...
                 */
                __ieee80211_sta_recalc_aggregates(sta, active_links);
        }

        for_each_set_bit(link_id, &add, IEEE80211_MLD_MAX_NUM_LINKS) {
                struct ieee80211_link_data *link;

                link = sdata_dereference(sdata->link[link_id], sdata);

                ieee80211_mgd_set_link_qos_params(link);
                ieee80211_link_info_change_notify(sdata, link,
                                                  BSS_CHANGED_ERP_CTS_PROT |
                                                  BSS_CHANGED_ERP_PREAMBLE |
                                                  BSS_CHANGED_ERP_SLOT |
                                                  BSS_CHANGED_HT |
                                                  BSS_CHANGED_BASIC_RATES |
                                                  BSS_CHANGED_BSSID |
                                                  BSS_CHANGED_CQM |
                                                  BSS_CHANGED_QOS |
                                                  BSS_CHANGED_TXPOWER |
                                                  BSS_CHANGED_BANDWIDTH |
                                                  BSS_CHANGED_TWT |
                                                  BSS_CHANGED_HE_OBSS_PD |
                                                  BSS_CHANGED_HE_BSS_COLOR);
        }

        old_active = sdata->vif.active_links;
        sdata->vif.active_links = active_links;

        if (rem) {
                ret = drv_change_vif_links(local, sdata, old_active,
                                           active_links, link_confs);
                WARN_ON_ONCE(ret);
        }

        return 0;
}

int ieee80211_set_active_links(struct ieee80211_vif *vif, u16 active_links)
{
        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
        struct ieee80211_local *local = sdata->local;
        u16 old_active;
        int ret;

        lockdep_assert_wiphy(local->hw.wiphy);

        if (WARN_ON(!active_links))
                return -EINVAL;

        old_active = sdata->vif.active_links;
        if (old_active == active_links)
                return 0;

        if (!drv_can_activate_links(local, sdata, active_links))
                return -EINVAL;

        if (old_active & active_links) {
                /*
                 * if there's at least one link that stays active across
                 * the change then switch to it (to those) first, and
                 * then enable the additional links
                 */
                ret = _ieee80211_set_active_links(sdata,
                                                  old_active & active_links);
                if (!ret)
                        ret = _ieee80211_set_active_links(sdata, active_links);
        } else {
                /* otherwise switch directly */
                ret = _ieee80211_set_active_links(sdata, active_links);
        }

        return ret;
}
EXPORT_SYMBOL_GPL(ieee80211_set_active_links);

void ieee80211_set_active_links_async(struct ieee80211_vif *vif,
                                      u16 active_links)
{
        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);

        if (WARN_ON(!active_links))
                return;

        if (!ieee80211_sdata_running(sdata))
                return;

        if (sdata->vif.type != NL80211_IFTYPE_STATION)
                return;

        if (active_links & ~ieee80211_vif_usable_links(&sdata->vif))
                return;

        /* nothing to do */
        if (sdata->vif.active_links == active_links)
                return;

        sdata->desired_active_links = active_links;
        wiphy_work_queue(sdata->local->hw.wiphy, &sdata->activate_links_work);
}
EXPORT_SYMBOL_GPL(ieee80211_set_active_links_async);
Linux
