/*
 * mac80211 TDLS handling code
 *
 * Copyright 2006-2010  Johannes Berg <johannes@sipsolutions.net>
 * Copyright 2014, Intel Corporation
 * Copyright 2014  Intel Mobile Communications GmbH
 *
 * This file is GPLv2 as found in COPYING.
 */

#include <linux/ieee80211.h>
#include <linux/log2.h>
#include <net/cfg80211.h>
#include "ieee80211_i.h"
#include "driver-ops.h"

/* give usermode some time for retries in setting up the TDLS session */
#define TDLS_PEER_SETUP_TIMEOUT (15 * HZ)

void ieee80211_tdls_peer_del_work(struct work_struct *wk)
{
        struct ieee80211_sub_if_data *sdata;
        struct ieee80211_local *local;

        sdata = container_of(wk, struct ieee80211_sub_if_data,
                             u.mgd.tdls_peer_del_work.work);
        local = sdata->local;

        mutex_lock(&local->mtx);
        if (!is_zero_ether_addr(sdata->u.mgd.tdls_peer)) {
                tdls_dbg(sdata, "TDLS del peer %pM\n", sdata->u.mgd.tdls_peer);
                sta_info_destroy_addr(sdata, sdata->u.mgd.tdls_peer);
                eth_zero_addr(sdata->u.mgd.tdls_peer);
        }
        mutex_unlock(&local->mtx);
}

static void ieee80211_tdls_add_ext_capab(struct ieee80211_local *local,
                                         struct sk_buff *skb)
{
        u8 *pos = (void *)skb_put(skb, 7);
        bool chan_switch = local->hw.wiphy->features &
                           NL80211_FEATURE_TDLS_CHANNEL_SWITCH;

        *pos++ = WLAN_EID_EXT_CAPABILITY;
        *pos++ = 5; /* len */
        *pos++ = 0x0;
        *pos++ = 0x0;
        *pos++ = 0x0;
        *pos++ = chan_switch ? WLAN_EXT_CAPA4_TDLS_CHAN_SWITCH : 0;
        *pos++ = WLAN_EXT_CAPA5_TDLS_ENABLED;
}

static u8
ieee80211_tdls_add_subband(struct ieee80211_sub_if_data *sdata,
                           struct sk_buff *skb, u16 start, u16 end,
                           u16 spacing)
{
        u8 subband_cnt = 0, ch_cnt = 0;
        struct ieee80211_channel *ch;
        struct cfg80211_chan_def chandef;
        int i, subband_start;
        struct wiphy *wiphy = sdata->local->hw.wiphy;

        for (i = start; i <= end; i += spacing) {
                if (!ch_cnt)
                        subband_start = i;

                ch = ieee80211_get_channel(sdata->local->hw.wiphy, i);
                if (ch) {
                        /* we will be active on the channel */
                        cfg80211_chandef_create(&chandef, ch,
                                                NL80211_CHAN_NO_HT);
                        if (cfg80211_reg_can_beacon_relax(wiphy, &chandef,
                                                          sdata->wdev.iftype)) {
                                ch_cnt++;
                                /*
                                 * check if the next channel is also part of
                                 * this allowed range
                                 */
                                continue;
                        }
                }

                /*
                 * we've reached the end of a range, with allowed channels
                 * found
                 */
                if (ch_cnt) {
                        u8 *pos = skb_put(skb, 2);
                        *pos++ = ieee80211_frequency_to_channel(subband_start);
                        *pos++ = ch_cnt;

                        subband_cnt++;
                        ch_cnt = 0;
                }
        }

        /* all channels in the requested range are allowed - add them here */
        if (ch_cnt) {
                u8 *pos = skb_put(skb, 2);
                *pos++ = ieee80211_frequency_to_channel(subband_start);
                *pos++ = ch_cnt;

                subband_cnt++;
        }

        return subband_cnt;
}

static void
ieee80211_tdls_add_supp_channels(struct ieee80211_sub_if_data *sdata,
                                 struct sk_buff *skb)
{
        /*
         * Add possible channels for TDLS. These are channels that are allowed
         * to be active.
         */
        u8 subband_cnt;
        u8 *pos = skb_put(skb, 2);

        *pos++ = WLAN_EID_SUPPORTED_CHANNELS;

        /*
         * 5GHz and 2GHz channels numbers can overlap. Ignore this for now, as
         * this doesn't happen in real world scenarios.
         */

        /* 2GHz, with 5MHz spacing */
        subband_cnt = ieee80211_tdls_add_subband(sdata, skb, 2412, 2472, 5);

        /* 5GHz, with 20MHz spacing */
        subband_cnt += ieee80211_tdls_add_subband(sdata, skb, 5000, 5825, 20);

        /* length */
        *pos = 2 * subband_cnt;
}

static void ieee80211_tdls_add_oper_classes(struct ieee80211_sub_if_data *sdata,
                                            struct sk_buff *skb)
{
        u8 *pos;
        u8 op_class;

        if (!ieee80211_chandef_to_operating_class(&sdata->vif.bss_conf.chandef,
                                                  &op_class))
                return;

        pos = skb_put(skb, 4);
        *pos++ = WLAN_EID_SUPPORTED_REGULATORY_CLASSES;
        *pos++ = 2; /* len */

        *pos++ = op_class;
        *pos++ = op_class; /* give current operating class as alternate too */
}

static void ieee80211_tdls_add_bss_coex_ie(struct sk_buff *skb)
{
        u8 *pos = (void *)skb_put(skb, 3);

        *pos++ = WLAN_EID_BSS_COEX_2040;
        *pos++ = 1; /* len */

        *pos++ = WLAN_BSS_COEX_INFORMATION_REQUEST;
}

static u16 ieee80211_get_tdls_sta_capab(struct ieee80211_sub_if_data *sdata,
                                        u16 status_code)
{
        /* The capability will be 0 when sending a failure code */
        if (status_code != 0)
                return 0;

        if (ieee80211_get_sdata_band(sdata) == IEEE80211_BAND_2GHZ) {
                return WLAN_CAPABILITY_SHORT_SLOT_TIME |
                       WLAN_CAPABILITY_SHORT_PREAMBLE;
        }

        return 0;
}

static void ieee80211_tdls_add_link_ie(struct ieee80211_sub_if_data *sdata,
                                       struct sk_buff *skb, const u8 *peer,
                                       bool initiator)
{
        struct ieee80211_tdls_lnkie *lnkid;
        const u8 *init_addr, *rsp_addr;

        if (initiator) {
                init_addr = sdata->vif.addr;
                rsp_addr = peer;
        } else {
                init_addr = peer;
                rsp_addr = sdata->vif.addr;
        }

        lnkid = (void *)skb_put(skb, sizeof(struct ieee80211_tdls_lnkie));

        lnkid->ie_type = WLAN_EID_LINK_ID;
        lnkid->ie_len = sizeof(struct ieee80211_tdls_lnkie) - 2;

        memcpy(lnkid->bssid, sdata->u.mgd.bssid, ETH_ALEN);
        memcpy(lnkid->init_sta, init_addr, ETH_ALEN);
        memcpy(lnkid->resp_sta, rsp_addr, ETH_ALEN);
}

static void
ieee80211_tdls_add_aid(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
{
        struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
        u8 *pos = (void *)skb_put(skb, 4);

        *pos++ = WLAN_EID_AID;
        *pos++ = 2; /* len */
        put_unaligned_le16(ifmgd->aid, pos);
}

/* translate numbering in the WMM parameter IE to the mac80211 notation */
static enum ieee80211_ac_numbers ieee80211_ac_from_wmm(int ac)
{
        switch (ac) {
        default:
                WARN_ON_ONCE(1);
        case 0:
                return IEEE80211_AC_BE;
        case 1:
                return IEEE80211_AC_BK;
        case 2:
                return IEEE80211_AC_VI;
        case 3:
                return IEEE80211_AC_VO;
        }
}

static u8 ieee80211_wmm_aci_aifsn(int aifsn, bool acm, int aci)
{
        u8 ret;

        ret = aifsn & 0x0f;
        if (acm)
                ret |= 0x10;
        ret |= (aci << 5) & 0x60;
        return ret;
}

static u8 ieee80211_wmm_ecw(u16 cw_min, u16 cw_max)
{
        return ((ilog2(cw_min + 1) << 0x0) & 0x0f) |
               ((ilog2(cw_max + 1) << 0x4) & 0xf0);
}

static void ieee80211_tdls_add_wmm_param_ie(struct ieee80211_sub_if_data *sdata,
                                            struct sk_buff *skb)
{
        struct ieee80211_wmm_param_ie *wmm;
        struct ieee80211_tx_queue_params *txq;
        int i;

        wmm = (void *)skb_put(skb, sizeof(*wmm));
        memset(wmm, 0, sizeof(*wmm));

        wmm->element_id = WLAN_EID_VENDOR_SPECIFIC;
        wmm->len = sizeof(*wmm) - 2;

        wmm->oui[0] = 0x00; /* Microsoft OUI 00:50:F2 */
        wmm->oui[1] = 0x50;
        wmm->oui[2] = 0xf2;
        wmm->oui_type = 2; /* WME */
        wmm->oui_subtype = 1; /* WME param */
        wmm->version = 1; /* WME ver */
        wmm->qos_info = 0; /* U-APSD not in use */

        /*
         * Use the EDCA parameters defined for the BSS, or default if the AP
         * doesn't support it, as mandated by 802.11-2012 section 10.22.4
         */
        for (i = 0; i < IEEE80211_NUM_ACS; i++) {
                txq = &sdata->tx_conf[ieee80211_ac_from_wmm(i)];
                wmm->ac[i].aci_aifsn = ieee80211_wmm_aci_aifsn(txq->aifs,
                                                               txq->acm, i);
                wmm->ac[i].cw = ieee80211_wmm_ecw(txq->cw_min, txq->cw_max);
                wmm->ac[i].txop_limit = cpu_to_le16(txq->txop);
        }
}

static void
ieee80211_tdls_add_setup_start_ies(struct ieee80211_sub_if_data *sdata,
                                   struct sk_buff *skb, const u8 *peer,
                                   u8 action_code, bool initiator,
                                   const u8 *extra_ies, size_t extra_ies_len)
{
        enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
        struct ieee80211_local *local = sdata->local;
        struct ieee80211_supported_band *sband;
        struct ieee80211_sta_ht_cap ht_cap;
        struct ieee80211_sta_vht_cap vht_cap;
        struct sta_info *sta = NULL;
        size_t offset = 0, noffset;
        u8 *pos;

        ieee80211_add_srates_ie(sdata, skb, false, band);
        ieee80211_add_ext_srates_ie(sdata, skb, false, band);
        ieee80211_tdls_add_supp_channels(sdata, skb);

        /* add any custom IEs that go before Extended Capabilities */
        if (extra_ies_len) {
                static const u8 before_ext_cap[] = {
                        WLAN_EID_SUPP_RATES,
                        WLAN_EID_COUNTRY,
                        WLAN_EID_EXT_SUPP_RATES,
                        WLAN_EID_SUPPORTED_CHANNELS,
                        WLAN_EID_RSN,
                };
                noffset = ieee80211_ie_split(extra_ies, extra_ies_len,
                                             before_ext_cap,
                                             ARRAY_SIZE(before_ext_cap),
                                             offset);
                pos = skb_put(skb, noffset - offset);
                memcpy(pos, extra_ies + offset, noffset - offset);
                offset = noffset;
        }

        ieee80211_tdls_add_ext_capab(local, skb);

        /* add the QoS element if we support it */
        if (local->hw.queues >= IEEE80211_NUM_ACS &&
            action_code != WLAN_PUB_ACTION_TDLS_DISCOVER_RES)
                ieee80211_add_wmm_info_ie(skb_put(skb, 9), 0); /* no U-APSD */

        /* add any custom IEs that go before HT capabilities */
        if (extra_ies_len) {
                static const u8 before_ht_cap[] = {
                        WLAN_EID_SUPP_RATES,
                        WLAN_EID_COUNTRY,
                        WLAN_EID_EXT_SUPP_RATES,
                        WLAN_EID_SUPPORTED_CHANNELS,
                        WLAN_EID_RSN,
                        WLAN_EID_EXT_CAPABILITY,
                        WLAN_EID_QOS_CAPA,
                        WLAN_EID_FAST_BSS_TRANSITION,
                        WLAN_EID_TIMEOUT_INTERVAL,
                        WLAN_EID_SUPPORTED_REGULATORY_CLASSES,
                };
                noffset = ieee80211_ie_split(extra_ies, extra_ies_len,
                                             before_ht_cap,
                                             ARRAY_SIZE(before_ht_cap),
                                             offset);
                pos = skb_put(skb, noffset - offset);
                memcpy(pos, extra_ies + offset, noffset - offset);
                offset = noffset;
        }

        rcu_read_lock();

        /* we should have the peer STA if we're already responding */
        if (action_code == WLAN_TDLS_SETUP_RESPONSE) {
                sta = sta_info_get(sdata, peer);
                if (WARN_ON_ONCE(!sta)) {
                        rcu_read_unlock();
                        return;
                }
        }

        ieee80211_tdls_add_oper_classes(sdata, skb);

        /*
         * with TDLS we can switch channels, and HT-caps are not necessarily
         * the same on all bands. The specification limits the setup to a
         * single HT-cap, so use the current band for now.
         */
        sband = local->hw.wiphy->bands[band];
        memcpy(&ht_cap, &sband->ht_cap, sizeof(ht_cap));

        if ((action_code == WLAN_TDLS_SETUP_REQUEST ||
             action_code == WLAN_PUB_ACTION_TDLS_DISCOVER_RES) &&
            ht_cap.ht_supported) {
                ieee80211_apply_htcap_overrides(sdata, &ht_cap);

                /* disable SMPS in TDLS initiator */
                ht_cap.cap |= WLAN_HT_CAP_SM_PS_DISABLED
                                << IEEE80211_HT_CAP_SM_PS_SHIFT;

                pos = skb_put(skb, sizeof(struct ieee80211_ht_cap) + 2);
                ieee80211_ie_build_ht_cap(pos, &ht_cap, ht_cap.cap);
        } else if (action_code == WLAN_TDLS_SETUP_RESPONSE &&
                   ht_cap.ht_supported && sta->sta.ht_cap.ht_supported) {
                /* disable SMPS in TDLS responder */
                sta->sta.ht_cap.cap |= WLAN_HT_CAP_SM_PS_DISABLED
                                        << IEEE80211_HT_CAP_SM_PS_SHIFT;

                /* the peer caps are already intersected with our own */
                memcpy(&ht_cap, &sta->sta.ht_cap, sizeof(ht_cap));

                pos = skb_put(skb, sizeof(struct ieee80211_ht_cap) + 2);
                ieee80211_ie_build_ht_cap(pos, &ht_cap, ht_cap.cap);
        }

        if (ht_cap.ht_supported &&
            (ht_cap.cap & IEEE80211_HT_CAP_SUP_WIDTH_20_40))
                ieee80211_tdls_add_bss_coex_ie(skb);

        ieee80211_tdls_add_link_ie(sdata, skb, peer, initiator);

        /* add any custom IEs that go before VHT capabilities */
        if (extra_ies_len) {
                static const u8 before_vht_cap[] = {
                        WLAN_EID_SUPP_RATES,
                        WLAN_EID_COUNTRY,
                        WLAN_EID_EXT_SUPP_RATES,
                        WLAN_EID_SUPPORTED_CHANNELS,
                        WLAN_EID_RSN,
                        WLAN_EID_EXT_CAPABILITY,
                        WLAN_EID_QOS_CAPA,
                        WLAN_EID_FAST_BSS_TRANSITION,
                        WLAN_EID_TIMEOUT_INTERVAL,
                        WLAN_EID_SUPPORTED_REGULATORY_CLASSES,
                        WLAN_EID_MULTI_BAND,
                };
                noffset = ieee80211_ie_split(extra_ies, extra_ies_len,
                                             before_vht_cap,
                                             ARRAY_SIZE(before_vht_cap),
                                             offset);
                pos = skb_put(skb, noffset - offset);
                memcpy(pos, extra_ies + offset, noffset - offset);
                offset = noffset;
        }

        /* build the VHT-cap similarly to the HT-cap */
        memcpy(&vht_cap, &sband->vht_cap, sizeof(vht_cap));
        if ((action_code == WLAN_TDLS_SETUP_REQUEST ||
             action_code == WLAN_PUB_ACTION_TDLS_DISCOVER_RES) &&
            vht_cap.vht_supported) {
                ieee80211_apply_vhtcap_overrides(sdata, &vht_cap);

                /* the AID is present only when VHT is implemented */
                if (action_code == WLAN_TDLS_SETUP_REQUEST)
                        ieee80211_tdls_add_aid(sdata, skb);

                pos = skb_put(skb, sizeof(struct ieee80211_vht_cap) + 2);
                ieee80211_ie_build_vht_cap(pos, &vht_cap, vht_cap.cap);
        } else if (action_code == WLAN_TDLS_SETUP_RESPONSE &&
                   vht_cap.vht_supported && sta->sta.vht_cap.vht_supported) {
                /* the peer caps are already intersected with our own */
                memcpy(&vht_cap, &sta->sta.vht_cap, sizeof(vht_cap));

                /* the AID is present only when VHT is implemented */
                ieee80211_tdls_add_aid(sdata, skb);

                pos = skb_put(skb, sizeof(struct ieee80211_vht_cap) + 2);
                ieee80211_ie_build_vht_cap(pos, &vht_cap, vht_cap.cap);
        }

        rcu_read_unlock();

        /* add any remaining IEs */
        if (extra_ies_len) {
                noffset = extra_ies_len;
                pos = skb_put(skb, noffset - offset);
                memcpy(pos, extra_ies + offset, noffset - offset);
        }

}

static void
ieee80211_tdls_add_setup_cfm_ies(struct ieee80211_sub_if_data *sdata,
                                 struct sk_buff *skb, const u8 *peer,
                                 bool initiator, const u8 *extra_ies,
                                 size_t extra_ies_len)
{
        struct ieee80211_local *local = sdata->local;
        struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
        size_t offset = 0, noffset;
        struct sta_info *sta, *ap_sta;
        enum ieee80211_band band = ieee80211_get_sdata_band(sdata);
        u8 *pos;

        rcu_read_lock();

        sta = sta_info_get(sdata, peer);
        ap_sta = sta_info_get(sdata, ifmgd->bssid);
        if (WARN_ON_ONCE(!sta || !ap_sta)) {
                rcu_read_unlock();
                return;
        }

        /* add any custom IEs that go before the QoS IE */
        if (extra_ies_len) {
                static const u8 before_qos[] = {
                        WLAN_EID_RSN,
                };
                noffset = ieee80211_ie_split(extra_ies, extra_ies_len,
                                             before_qos,
                                             ARRAY_SIZE(before_qos),
                                             offset);
                pos = skb_put(skb, noffset - offset);
                memcpy(pos, extra_ies + offset, noffset - offset);
                offset = noffset;
        }

        /* add the QoS param IE if both the peer and we support it */
        if (local->hw.queues >= IEEE80211_NUM_ACS && sta->sta.wme)
                ieee80211_tdls_add_wmm_param_ie(sdata, skb);

        /* add any custom IEs that go before HT operation */
        if (extra_ies_len) {
                static const u8 before_ht_op[] = {
                        WLAN_EID_RSN,
                        WLAN_EID_QOS_CAPA,
                        WLAN_EID_FAST_BSS_TRANSITION,
                        WLAN_EID_TIMEOUT_INTERVAL,
                };
                noffset = ieee80211_ie_split(extra_ies, extra_ies_len,
                                             before_ht_op,
                                             ARRAY_SIZE(before_ht_op),
                                             offset);
                pos = skb_put(skb, noffset - offset);
                memcpy(pos, extra_ies + offset, noffset - offset);
                offset = noffset;
        }

        /* if HT support is only added in TDLS, we need an HT-operation IE */
        if (!ap_sta->sta.ht_cap.ht_supported && sta->sta.ht_cap.ht_supported) {
                pos = skb_put(skb, 2 + sizeof(struct ieee80211_ht_operation));
                /* send an empty HT operation IE */
                ieee80211_ie_build_ht_oper(pos, &sta->sta.ht_cap,
                                           &sdata->vif.bss_conf.chandef, 0);
        }

        ieee80211_tdls_add_link_ie(sdata, skb, peer, initiator);

        /* only include VHT-operation if not on the 2.4GHz band */
        if (band != IEEE80211_BAND_2GHZ && sta->sta.vht_cap.vht_supported) {
                pos = skb_put(skb, 2 + sizeof(struct ieee80211_vht_operation));
                ieee80211_ie_build_vht_oper(pos, &sta->sta.vht_cap,
                                            &sdata->vif.bss_conf.chandef);
        }

        rcu_read_unlock();

        /* add any remaining IEs */
        if (extra_ies_len) {
                noffset = extra_ies_len;
                pos = skb_put(skb, noffset - offset);
                memcpy(pos, extra_ies + offset, noffset - offset);
        }
}

static void
ieee80211_tdls_add_chan_switch_req_ies(struct ieee80211_sub_if_data *sdata,
                                       struct sk_buff *skb, const u8 *peer,
                                       bool initiator, const u8 *extra_ies,
                                       size_t extra_ies_len, u8 oper_class,
                                       struct cfg80211_chan_def *chandef)
{
        struct ieee80211_tdls_data *tf;
        size_t offset = 0, noffset;
        u8 *pos;

        if (WARN_ON_ONCE(!chandef))
                return;

        tf = (void *)skb->data;
        tf->u.chan_switch_req.target_channel =
                ieee80211_frequency_to_channel(chandef->chan->center_freq);
        tf->u.chan_switch_req.oper_class = oper_class;

        if (extra_ies_len) {
                static const u8 before_lnkie[] = {
                        WLAN_EID_SECONDARY_CHANNEL_OFFSET,
                };
                noffset = ieee80211_ie_split(extra_ies, extra_ies_len,
                                             before_lnkie,
                                             ARRAY_SIZE(before_lnkie),
                                             offset);
                pos = skb_put(skb, noffset - offset);
                memcpy(pos, extra_ies + offset, noffset - offset);
                offset = noffset;
        }

        ieee80211_tdls_add_link_ie(sdata, skb, peer, initiator);

        /* add any remaining IEs */
        if (extra_ies_len) {
                noffset = extra_ies_len;
                pos = skb_put(skb, noffset - offset);
                memcpy(pos, extra_ies + offset, noffset - offset);
        }
}

static void
ieee80211_tdls_add_chan_switch_resp_ies(struct ieee80211_sub_if_data *sdata,
                                        struct sk_buff *skb, const u8 *peer,
                                        u16 status_code, bool initiator,
                                        const u8 *extra_ies,
                                        size_t extra_ies_len)
{
        if (status_code == 0)
                ieee80211_tdls_add_link_ie(sdata, skb, peer, initiator);

        if (extra_ies_len)
                memcpy(skb_put(skb, extra_ies_len), extra_ies, extra_ies_len);
}

static void ieee80211_tdls_add_ies(struct ieee80211_sub_if_data *sdata,
                                   struct sk_buff *skb, const u8 *peer,
                                   u8 action_code, u16 status_code,
                                   bool initiator, const u8 *extra_ies,
                                   size_t extra_ies_len, u8 oper_class,
                                   struct cfg80211_chan_def *chandef)
{
        switch (action_code) {
        case WLAN_TDLS_SETUP_REQUEST:
        case WLAN_TDLS_SETUP_RESPONSE:
        case WLAN_PUB_ACTION_TDLS_DISCOVER_RES:
                if (status_code == 0)
                        ieee80211_tdls_add_setup_start_ies(sdata, skb, peer,
                                                           action_code,
                                                           initiator,
                                                           extra_ies,
                                                           extra_ies_len);
                break;
        case WLAN_TDLS_SETUP_CONFIRM:
                if (status_code == 0)
                        ieee80211_tdls_add_setup_cfm_ies(sdata, skb, peer,
                                                         initiator, extra_ies,
                                                         extra_ies_len);
                break;
        case WLAN_TDLS_TEARDOWN:
        case WLAN_TDLS_DISCOVERY_REQUEST:
                if (extra_ies_len)
                        memcpy(skb_put(skb, extra_ies_len), extra_ies,
                               extra_ies_len);
                if (status_code == 0 || action_code == WLAN_TDLS_TEARDOWN)
                        ieee80211_tdls_add_link_ie(sdata, skb, peer, initiator);
                break;
        case WLAN_TDLS_CHANNEL_SWITCH_REQUEST:
                ieee80211_tdls_add_chan_switch_req_ies(sdata, skb, peer,
                                                       initiator, extra_ies,
                                                       extra_ies_len,
                                                       oper_class, chandef);
                break;
        case WLAN_TDLS_CHANNEL_SWITCH_RESPONSE:
                ieee80211_tdls_add_chan_switch_resp_ies(sdata, skb, peer,
                                                        status_code,
                                                        initiator, extra_ies,
                                                        extra_ies_len);
                break;
        }

}

static int
ieee80211_prep_tdls_encap_data(struct wiphy *wiphy, struct net_device *dev,
                               const u8 *peer, u8 action_code, u8 dialog_token,
                               u16 status_code, struct sk_buff *skb)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        struct ieee80211_tdls_data *tf;

        tf = (void *)skb_put(skb, offsetof(struct ieee80211_tdls_data, u));

        memcpy(tf->da, peer, ETH_ALEN);
        memcpy(tf->sa, sdata->vif.addr, ETH_ALEN);
        tf->ether_type = cpu_to_be16(ETH_P_TDLS);
        tf->payload_type = WLAN_TDLS_SNAP_RFTYPE;

        /* network header is after the ethernet header */
        skb_set_network_header(skb, ETH_HLEN);

        switch (action_code) {
        case WLAN_TDLS_SETUP_REQUEST:
                tf->category = WLAN_CATEGORY_TDLS;
                tf->action_code = WLAN_TDLS_SETUP_REQUEST;

                skb_put(skb, sizeof(tf->u.setup_req));
                tf->u.setup_req.dialog_token = dialog_token;
                tf->u.setup_req.capability =
                        cpu_to_le16(ieee80211_get_tdls_sta_capab(sdata,
                                                                 status_code));
                break;
        case WLAN_TDLS_SETUP_RESPONSE:
                tf->category = WLAN_CATEGORY_TDLS;
                tf->action_code = WLAN_TDLS_SETUP_RESPONSE;

                skb_put(skb, sizeof(tf->u.setup_resp));
                tf->u.setup_resp.status_code = cpu_to_le16(status_code);
                tf->u.setup_resp.dialog_token = dialog_token;
                tf->u.setup_resp.capability =
                        cpu_to_le16(ieee80211_get_tdls_sta_capab(sdata,
                                                                 status_code));
                break;
        case WLAN_TDLS_SETUP_CONFIRM:
                tf->category = WLAN_CATEGORY_TDLS;
                tf->action_code = WLAN_TDLS_SETUP_CONFIRM;

                skb_put(skb, sizeof(tf->u.setup_cfm));
                tf->u.setup_cfm.status_code = cpu_to_le16(status_code);
                tf->u.setup_cfm.dialog_token = dialog_token;
                break;
        case WLAN_TDLS_TEARDOWN:
                tf->category = WLAN_CATEGORY_TDLS;
                tf->action_code = WLAN_TDLS_TEARDOWN;

                skb_put(skb, sizeof(tf->u.teardown));
                tf->u.teardown.reason_code = cpu_to_le16(status_code);
                break;
        case WLAN_TDLS_DISCOVERY_REQUEST:
                tf->category = WLAN_CATEGORY_TDLS;
                tf->action_code = WLAN_TDLS_DISCOVERY_REQUEST;

                skb_put(skb, sizeof(tf->u.discover_req));
                tf->u.discover_req.dialog_token = dialog_token;
                break;
        case WLAN_TDLS_CHANNEL_SWITCH_REQUEST:
                tf->category = WLAN_CATEGORY_TDLS;
                tf->action_code = WLAN_TDLS_CHANNEL_SWITCH_REQUEST;

                skb_put(skb, sizeof(tf->u.chan_switch_req));
                break;
        case WLAN_TDLS_CHANNEL_SWITCH_RESPONSE:
                tf->category = WLAN_CATEGORY_TDLS;
                tf->action_code = WLAN_TDLS_CHANNEL_SWITCH_RESPONSE;

                skb_put(skb, sizeof(tf->u.chan_switch_resp));
                tf->u.chan_switch_resp.status_code = cpu_to_le16(status_code);
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int
ieee80211_prep_tdls_direct(struct wiphy *wiphy, struct net_device *dev,
                           const u8 *peer, u8 action_code, u8 dialog_token,
                           u16 status_code, struct sk_buff *skb)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        struct ieee80211_mgmt *mgmt;

        mgmt = (void *)skb_put(skb, 24);
        memset(mgmt, 0, 24);
        memcpy(mgmt->da, peer, ETH_ALEN);
        memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
        memcpy(mgmt->bssid, sdata->u.mgd.bssid, ETH_ALEN);

        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
                                          IEEE80211_STYPE_ACTION);

        switch (action_code) {
        case WLAN_PUB_ACTION_TDLS_DISCOVER_RES:
                skb_put(skb, 1 + sizeof(mgmt->u.action.u.tdls_discover_resp));
                mgmt->u.action.category = WLAN_CATEGORY_PUBLIC;
                mgmt->u.action.u.tdls_discover_resp.action_code =
                        WLAN_PUB_ACTION_TDLS_DISCOVER_RES;
                mgmt->u.action.u.tdls_discover_resp.dialog_token =
                        dialog_token;
                mgmt->u.action.u.tdls_discover_resp.capability =
                        cpu_to_le16(ieee80211_get_tdls_sta_capab(sdata,
                                                                 status_code));
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static struct sk_buff *
ieee80211_tdls_build_mgmt_packet_data(struct ieee80211_sub_if_data *sdata,
                                      const u8 *peer, u8 action_code,
                                      u8 dialog_token, u16 status_code,
                                      bool initiator, const u8 *extra_ies,
                                      size_t extra_ies_len, u8 oper_class,
                                      struct cfg80211_chan_def *chandef)
{
        struct ieee80211_local *local = sdata->local;
        struct sk_buff *skb;
        int ret;

        skb = netdev_alloc_skb(sdata->dev,
                               local->hw.extra_tx_headroom +
                               max(sizeof(struct ieee80211_mgmt),
                                   sizeof(struct ieee80211_tdls_data)) +
                               50 + /* supported rates */
                               7 + /* ext capab */
                               26 + /* max(WMM-info, WMM-param) */
                               2 + max(sizeof(struct ieee80211_ht_cap),
                                       sizeof(struct ieee80211_ht_operation)) +
                               2 + max(sizeof(struct ieee80211_vht_cap),
                                       sizeof(struct ieee80211_vht_operation)) +
                               50 + /* supported channels */
                               3 + /* 40/20 BSS coex */
                               4 + /* AID */
                               4 + /* oper classes */
                               extra_ies_len +
                               sizeof(struct ieee80211_tdls_lnkie));
        if (!skb)
                return NULL;

        skb_reserve(skb, local->hw.extra_tx_headroom);

        switch (action_code) {
        case WLAN_TDLS_SETUP_REQUEST:
        case WLAN_TDLS_SETUP_RESPONSE:
        case WLAN_TDLS_SETUP_CONFIRM:
        case WLAN_TDLS_TEARDOWN:
        case WLAN_TDLS_DISCOVERY_REQUEST:
        case WLAN_TDLS_CHANNEL_SWITCH_REQUEST:
        case WLAN_TDLS_CHANNEL_SWITCH_RESPONSE:
                ret = ieee80211_prep_tdls_encap_data(local->hw.wiphy,
                                                     sdata->dev, peer,
                                                     action_code, dialog_token,
                                                     status_code, skb);
                break;
        case WLAN_PUB_ACTION_TDLS_DISCOVER_RES:
                ret = ieee80211_prep_tdls_direct(local->hw.wiphy, sdata->dev,
                                                 peer, action_code,
                                                 dialog_token, status_code,
                                                 skb);
                break;
        default:
                ret = -ENOTSUPP;
                break;
        }

        if (ret < 0)
                goto fail;

        ieee80211_tdls_add_ies(sdata, skb, peer, action_code, status_code,
                               initiator, extra_ies, extra_ies_len, oper_class,
                               chandef);
        return skb;

fail:
        dev_kfree_skb(skb);
        return NULL;
}

static int
ieee80211_tdls_prep_mgmt_packet(struct wiphy *wiphy, struct net_device *dev,
                                const u8 *peer, u8 action_code, u8 dialog_token,
                                u16 status_code, u32 peer_capability,
                                bool initiator, const u8 *extra_ies,
                                size_t extra_ies_len, u8 oper_class,
                                struct cfg80211_chan_def *chandef)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        struct sk_buff *skb = NULL;
        struct sta_info *sta;
        u32 flags = 0;
        int ret = 0;

        rcu_read_lock();
        sta = sta_info_get(sdata, peer);

        /* infer the initiator if we can, to support old userspace */
        switch (action_code) {
        case WLAN_TDLS_SETUP_REQUEST:
                if (sta) {
                        set_sta_flag(sta, WLAN_STA_TDLS_INITIATOR);
                        sta->sta.tdls_initiator = false;
                }
                /* fall-through */
        case WLAN_TDLS_SETUP_CONFIRM:
        case WLAN_TDLS_DISCOVERY_REQUEST:
                initiator = true;
                break;
        case WLAN_TDLS_SETUP_RESPONSE:
                /*
                 * In some testing scenarios, we send a request and response.
                 * Make the last packet sent take effect for the initiator
                 * value.
                 */
                if (sta) {
                        clear_sta_flag(sta, WLAN_STA_TDLS_INITIATOR);
                        sta->sta.tdls_initiator = true;
                }
                /* fall-through */
        case WLAN_PUB_ACTION_TDLS_DISCOVER_RES:
                initiator = false;
                break;
        case WLAN_TDLS_TEARDOWN:
        case WLAN_TDLS_CHANNEL_SWITCH_REQUEST:
        case WLAN_TDLS_CHANNEL_SWITCH_RESPONSE:
                /* any value is ok */
                break;
        default:
                ret = -ENOTSUPP;
                break;
        }

        if (sta && test_sta_flag(sta, WLAN_STA_TDLS_INITIATOR))
                initiator = true;

        rcu_read_unlock();
        if (ret < 0)
                goto fail;

        skb = ieee80211_tdls_build_mgmt_packet_data(sdata, peer, action_code,
                                                    dialog_token, status_code,
                                                    initiator, extra_ies,
                                                    extra_ies_len, oper_class,
                                                    chandef);
        if (!skb) {
                ret = -EINVAL;
                goto fail;
        }

        if (action_code == WLAN_PUB_ACTION_TDLS_DISCOVER_RES) {
                ieee80211_tx_skb(sdata, skb);
                return 0;
        }

        /*
         * According to 802.11z: Setup req/resp are sent in AC_BK, otherwise
         * we should default to AC_VI.
         */
        switch (action_code) {
        case WLAN_TDLS_SETUP_REQUEST:
        case WLAN_TDLS_SETUP_RESPONSE:
                skb_set_queue_mapping(skb, IEEE80211_AC_BK);
                skb->priority = 2;
                break;
        default:
                skb_set_queue_mapping(skb, IEEE80211_AC_VI);
                skb->priority = 5;
                break;
        }

        /*
         * Set the WLAN_TDLS_TEARDOWN flag to indicate a teardown in progress.
         * Later, if no ACK is returned from peer, we will re-send the teardown
         * packet through the AP.
         */
        if ((action_code == WLAN_TDLS_TEARDOWN) &&
            ieee80211_hw_check(&sdata->local->hw, REPORTS_TX_ACK_STATUS)) {
                bool try_resend; /* Should we keep skb for possible resend */

                /* If not sending directly to peer - no point in keeping skb */
                rcu_read_lock();
                sta = sta_info_get(sdata, peer);
                try_resend = sta && test_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH);
                rcu_read_unlock();

                spin_lock_bh(&sdata->u.mgd.teardown_lock);
                if (try_resend && !sdata->u.mgd.teardown_skb) {
                        /* Mark it as requiring TX status callback  */
                        flags |= IEEE80211_TX_CTL_REQ_TX_STATUS |
                                 IEEE80211_TX_INTFL_MLME_CONN_TX;

                        /*
                         * skb is copied since mac80211 will later set
                         * properties that might not be the same as the AP,
                         * such as encryption, QoS, addresses, etc.
                         *
                         * No problem if skb_copy() fails, so no need to check.
                         */
                        sdata->u.mgd.teardown_skb = skb_copy(skb, GFP_ATOMIC);
                        sdata->u.mgd.orig_teardown_skb = skb;
                }
                spin_unlock_bh(&sdata->u.mgd.teardown_lock);
        }

        /* disable bottom halves when entering the Tx path */
        local_bh_disable();
        __ieee80211_subif_start_xmit(skb, dev, flags);
        local_bh_enable();

        return ret;

fail:
        dev_kfree_skb(skb);
        return ret;
}

static int
ieee80211_tdls_mgmt_setup(struct wiphy *wiphy, struct net_device *dev,
                          const u8 *peer, u8 action_code, u8 dialog_token,
                          u16 status_code, u32 peer_capability, bool initiator,
                          const u8 *extra_ies, size_t extra_ies_len)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        struct ieee80211_local *local = sdata->local;
        int ret;

        mutex_lock(&local->mtx);

        /* we don't support concurrent TDLS peer setups */
        if (!is_zero_ether_addr(sdata->u.mgd.tdls_peer) &&
            !ether_addr_equal(sdata->u.mgd.tdls_peer, peer)) {
                ret = -EBUSY;
                goto out_unlock;
        }

        /*
         * make sure we have a STA representing the peer so we drop or buffer
         * non-TDLS-setup frames to the peer. We can't send other packets
         * during setup through the AP path.

         * Allow error packets to be sent - sometimes we don't even add a STA
         * before failing the setup.
         */
        if (status_code == 0) {
                rcu_read_lock();
                if (!sta_info_get(sdata, peer)) {
                        rcu_read_unlock();
                        ret = -ENOLINK;
                        goto out_unlock;
                }
                rcu_read_unlock();
        }

        ieee80211_flush_queues(local, sdata, false);
        memcpy(sdata->u.mgd.tdls_peer, peer, ETH_ALEN);
        mutex_unlock(&local->mtx);

        /* we cannot take the mutex while preparing the setup packet */
        ret = ieee80211_tdls_prep_mgmt_packet(wiphy, dev, peer, action_code,
                                              dialog_token, status_code,
                                              peer_capability, initiator,
                                              extra_ies, extra_ies_len, 0,
                                              NULL);
        if (ret < 0) {
                mutex_lock(&local->mtx);
                eth_zero_addr(sdata->u.mgd.tdls_peer);
                mutex_unlock(&local->mtx);
                return ret;
        }

        ieee80211_queue_delayed_work(&sdata->local->hw,
                                     &sdata->u.mgd.tdls_peer_del_work,
                                     TDLS_PEER_SETUP_TIMEOUT);
        return 0;

out_unlock:
        mutex_unlock(&local->mtx);
        return ret;
}

static int
ieee80211_tdls_mgmt_teardown(struct wiphy *wiphy, struct net_device *dev,
                             const u8 *peer, u8 action_code, u8 dialog_token,
                             u16 status_code, u32 peer_capability,
                             bool initiator, const u8 *extra_ies,
                             size_t extra_ies_len)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        struct ieee80211_local *local = sdata->local;
        struct sta_info *sta;
        int ret;

        /*
         * No packets can be transmitted to the peer via the AP during setup -
         * the STA is set as a TDLS peer, but is not authorized.
         * During teardown, we prevent direct transmissions by stopping the
         * queues and flushing all direct packets.
         */
        ieee80211_stop_vif_queues(local, sdata,
                                  IEEE80211_QUEUE_STOP_REASON_TDLS_TEARDOWN);
        ieee80211_flush_queues(local, sdata, false);

        ret = ieee80211_tdls_prep_mgmt_packet(wiphy, dev, peer, action_code,
                                              dialog_token, status_code,
                                              peer_capability, initiator,
                                              extra_ies, extra_ies_len, 0,
                                              NULL);
        if (ret < 0)
                sdata_err(sdata, "Failed sending TDLS teardown packet %d\n",
                          ret);

        /*
         * Remove the STA AUTH flag to force further traffic through the AP. If
         * the STA was unreachable, it was already removed.
         */
        rcu_read_lock();
        sta = sta_info_get(sdata, peer);
        if (sta)
                clear_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH);
        rcu_read_unlock();

        ieee80211_wake_vif_queues(local, sdata,
                                  IEEE80211_QUEUE_STOP_REASON_TDLS_TEARDOWN);

        return 0;
}

int ieee80211_tdls_mgmt(struct wiphy *wiphy, struct net_device *dev,
                        const u8 *peer, u8 action_code, u8 dialog_token,
                        u16 status_code, u32 peer_capability,
                        bool initiator, const u8 *extra_ies,
                        size_t extra_ies_len)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        int ret;

        if (!(wiphy->flags & WIPHY_FLAG_SUPPORTS_TDLS))
                return -ENOTSUPP;

        /* make sure we are in managed mode, and associated */
        if (sdata->vif.type != NL80211_IFTYPE_STATION ||
            !sdata->u.mgd.associated)
                return -EINVAL;

        switch (action_code) {
        case WLAN_TDLS_SETUP_REQUEST:
        case WLAN_TDLS_SETUP_RESPONSE:
                ret = ieee80211_tdls_mgmt_setup(wiphy, dev, peer, action_code,
                                                dialog_token, status_code,
                                                peer_capability, initiator,
                                                extra_ies, extra_ies_len);
                break;
        case WLAN_TDLS_TEARDOWN:
                ret = ieee80211_tdls_mgmt_teardown(wiphy, dev, peer,
                                                   action_code, dialog_token,
                                                   status_code,
                                                   peer_capability, initiator,
                                                   extra_ies, extra_ies_len);
                break;
        case WLAN_TDLS_DISCOVERY_REQUEST:
                /*
                 * Protect the discovery so we can hear the TDLS discovery
                 * response frame. It is transmitted directly and not buffered
                 * by the AP.
                 */
                drv_mgd_protect_tdls_discover(sdata->local, sdata);
                /* fall-through */
        case WLAN_TDLS_SETUP_CONFIRM:
        case WLAN_PUB_ACTION_TDLS_DISCOVER_RES:
                /* no special handling */
                ret = ieee80211_tdls_prep_mgmt_packet(wiphy, dev, peer,
                                                      action_code,
                                                      dialog_token,
                                                      status_code,
                                                      peer_capability,
                                                      initiator, extra_ies,
                                                      extra_ies_len, 0, NULL);
                break;
        default:
                ret = -EOPNOTSUPP;
                break;
        }

        tdls_dbg(sdata, "TDLS mgmt action %d peer %pM status %d\n",
                 action_code, peer, ret);
        return ret;
}

int ieee80211_tdls_oper(struct wiphy *wiphy, struct net_device *dev,
                        const u8 *peer, enum nl80211_tdls_operation oper)
{
        struct sta_info *sta;
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        struct ieee80211_local *local = sdata->local;
        int ret;

        if (!(wiphy->flags & WIPHY_FLAG_SUPPORTS_TDLS))
                return -ENOTSUPP;

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

        switch (oper) {
        case NL80211_TDLS_ENABLE_LINK:
        case NL80211_TDLS_DISABLE_LINK:
                break;
        case NL80211_TDLS_TEARDOWN:
        case NL80211_TDLS_SETUP:
        case NL80211_TDLS_DISCOVERY_REQ:
                /* We don't support in-driver setup/teardown/discovery */
                return -ENOTSUPP;
        }

        mutex_lock(&local->mtx);
        tdls_dbg(sdata, "TDLS oper %d peer %pM\n", oper, peer);

        switch (oper) {
        case NL80211_TDLS_ENABLE_LINK:
                if (sdata->vif.csa_active) {
                        tdls_dbg(sdata, "TDLS: disallow link during CSA\n");
                        ret = -EBUSY;
                        break;
                }

                rcu_read_lock();
                sta = sta_info_get(sdata, peer);
                if (!sta) {
                        rcu_read_unlock();
                        ret = -ENOLINK;
                        break;
                }

                set_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH);
                rcu_read_unlock();

                WARN_ON_ONCE(is_zero_ether_addr(sdata->u.mgd.tdls_peer) ||
                             !ether_addr_equal(sdata->u.mgd.tdls_peer, peer));
                ret = 0;
                break;
        case NL80211_TDLS_DISABLE_LINK:
                /*
                 * The teardown message in ieee80211_tdls_mgmt_teardown() was
                 * created while the queues were stopped, so it might still be
                 * pending. Before flushing the queues we need to be sure the
                 * message is handled by the tasklet handling pending messages,
                 * otherwise we might start destroying the station before
                 * sending the teardown packet.
                 * Note that this only forces the tasklet to flush pendings -
                 * not to stop the tasklet from rescheduling itself.
                 */
                tasklet_kill(&local->tx_pending_tasklet);
                /* flush a potentially queued teardown packet */
                ieee80211_flush_queues(local, sdata, false);

                ret = sta_info_destroy_addr(sdata, peer);
                break;
        default:
                ret = -ENOTSUPP;
                break;
        }

        if (ret == 0 && ether_addr_equal(sdata->u.mgd.tdls_peer, peer)) {
                cancel_delayed_work(&sdata->u.mgd.tdls_peer_del_work);
                eth_zero_addr(sdata->u.mgd.tdls_peer);
        }

        mutex_unlock(&local->mtx);
        return ret;
}

void ieee80211_tdls_oper_request(struct ieee80211_vif *vif, const u8 *peer,
                                 enum nl80211_tdls_operation oper,
                                 u16 reason_code, gfp_t gfp)
{
        struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);

        if (vif->type != NL80211_IFTYPE_STATION || !vif->bss_conf.assoc) {
                sdata_err(sdata, "Discarding TDLS oper %d - not STA or disconnected\n",
                          oper);
                return;
        }

        cfg80211_tdls_oper_request(sdata->dev, peer, oper, reason_code, gfp);
}
EXPORT_SYMBOL(ieee80211_tdls_oper_request);

static void
iee80211_tdls_add_ch_switch_timing(u8 *buf, u16 switch_time, u16 switch_timeout)
{
        struct ieee80211_ch_switch_timing *ch_sw;

        *buf++ = WLAN_EID_CHAN_SWITCH_TIMING;
        *buf++ = sizeof(struct ieee80211_ch_switch_timing);

        ch_sw = (void *)buf;
        ch_sw->switch_time = cpu_to_le16(switch_time);
        ch_sw->switch_timeout = cpu_to_le16(switch_timeout);
}

/* find switch timing IE in SKB ready for Tx */
static const u8 *ieee80211_tdls_find_sw_timing_ie(struct sk_buff *skb)
{
        struct ieee80211_tdls_data *tf;
        const u8 *ie_start;

        /*
         * Get the offset for the new location of the switch timing IE.
         * The SKB network header will now point to the "payload_type"
         * element of the TDLS data frame struct.
         */
        tf = container_of(skb->data + skb_network_offset(skb),
                          struct ieee80211_tdls_data, payload_type);
        ie_start = tf->u.chan_switch_req.variable;
        return cfg80211_find_ie(WLAN_EID_CHAN_SWITCH_TIMING, ie_start,
                                skb->len - (ie_start - skb->data));
}

static struct sk_buff *
ieee80211_tdls_ch_sw_tmpl_get(struct sta_info *sta, u8 oper_class,
                              struct cfg80211_chan_def *chandef,
                              u32 *ch_sw_tm_ie_offset)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        u8 extra_ies[2 + sizeof(struct ieee80211_sec_chan_offs_ie) +
                     2 + sizeof(struct ieee80211_ch_switch_timing)];
        int extra_ies_len = 2 + sizeof(struct ieee80211_ch_switch_timing);
        u8 *pos = extra_ies;
        struct sk_buff *skb;

        /*
         * if chandef points to a wide channel add a Secondary-Channel
         * Offset information element
         */
        if (chandef->width == NL80211_CHAN_WIDTH_40) {
                struct ieee80211_sec_chan_offs_ie *sec_chan_ie;
                bool ht40plus;

                *pos++ = WLAN_EID_SECONDARY_CHANNEL_OFFSET;
                *pos++ = sizeof(*sec_chan_ie);
                sec_chan_ie = (void *)pos;

                ht40plus = cfg80211_get_chandef_type(chandef) ==
                                                        NL80211_CHAN_HT40PLUS;
                sec_chan_ie->sec_chan_offs = ht40plus ?
                                             IEEE80211_HT_PARAM_CHA_SEC_ABOVE :
                                             IEEE80211_HT_PARAM_CHA_SEC_BELOW;
                pos += sizeof(*sec_chan_ie);

                extra_ies_len += 2 + sizeof(struct ieee80211_sec_chan_offs_ie);
        }

        /* just set the values to 0, this is a template */
        iee80211_tdls_add_ch_switch_timing(pos, 0, 0);

        skb = ieee80211_tdls_build_mgmt_packet_data(sdata, sta->sta.addr,
                                              WLAN_TDLS_CHANNEL_SWITCH_REQUEST,
                                              0, 0, !sta->sta.tdls_initiator,
                                              extra_ies, extra_ies_len,
                                              oper_class, chandef);
        if (!skb)
                return NULL;

        skb = ieee80211_build_data_template(sdata, skb, 0);
        if (IS_ERR(skb)) {
                tdls_dbg(sdata, "Failed building TDLS channel switch frame\n");
                return NULL;
        }

        if (ch_sw_tm_ie_offset) {
                const u8 *tm_ie = ieee80211_tdls_find_sw_timing_ie(skb);

                if (!tm_ie) {
                        tdls_dbg(sdata, "No switch timing IE in TDLS switch\n");
                        dev_kfree_skb_any(skb);
                        return NULL;
                }

                *ch_sw_tm_ie_offset = tm_ie - skb->data;
        }

        tdls_dbg(sdata,
                 "TDLS channel switch request template for %pM ch %d width %d\n",
                 sta->sta.addr, chandef->chan->center_freq, chandef->width);
        return skb;
}

int
ieee80211_tdls_channel_switch(struct wiphy *wiphy, struct net_device *dev,
                              const u8 *addr, u8 oper_class,
                              struct cfg80211_chan_def *chandef)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        struct ieee80211_local *local = sdata->local;
        struct sta_info *sta;
        struct sk_buff *skb = NULL;
        u32 ch_sw_tm_ie;
        int ret;

        mutex_lock(&local->sta_mtx);
        sta = sta_info_get(sdata, addr);
        if (!sta) {
                tdls_dbg(sdata,
                         "Invalid TDLS peer %pM for channel switch request\n",
                         addr);
                ret = -ENOENT;
                goto out;
        }

        if (!test_sta_flag(sta, WLAN_STA_TDLS_CHAN_SWITCH)) {
                tdls_dbg(sdata, "TDLS channel switch unsupported by %pM\n",
                         addr);
                ret = -ENOTSUPP;
                goto out;
        }

        skb = ieee80211_tdls_ch_sw_tmpl_get(sta, oper_class, chandef,
                                            &ch_sw_tm_ie);
        if (!skb) {
                ret = -ENOENT;
                goto out;
        }

        ret = drv_tdls_channel_switch(local, sdata, &sta->sta, oper_class,
                                      chandef, skb, ch_sw_tm_ie);
        if (!ret)
                set_sta_flag(sta, WLAN_STA_TDLS_OFF_CHANNEL);

out:
        mutex_unlock(&local->sta_mtx);
        dev_kfree_skb_any(skb);
        return ret;
}

void
ieee80211_tdls_cancel_channel_switch(struct wiphy *wiphy,
                                     struct net_device *dev,
                                     const u8 *addr)
{
        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
        struct ieee80211_local *local = sdata->local;
        struct sta_info *sta;

        mutex_lock(&local->sta_mtx);
        sta = sta_info_get(sdata, addr);
        if (!sta) {
                tdls_dbg(sdata,
                         "Invalid TDLS peer %pM for channel switch cancel\n",
                         addr);
                goto out;
        }

        if (!test_sta_flag(sta, WLAN_STA_TDLS_OFF_CHANNEL)) {
                tdls_dbg(sdata, "TDLS channel switch not initiated by %pM\n",
                         addr);
                goto out;
        }

        drv_tdls_cancel_channel_switch(local, sdata, &sta->sta);
        clear_sta_flag(sta, WLAN_STA_TDLS_OFF_CHANNEL);

out:
        mutex_unlock(&local->sta_mtx);
}

static struct sk_buff *
ieee80211_tdls_ch_sw_resp_tmpl_get(struct sta_info *sta,
                                   u32 *ch_sw_tm_ie_offset)
{
        struct ieee80211_sub_if_data *sdata = sta->sdata;
        struct sk_buff *skb;
        u8 extra_ies[2 + sizeof(struct ieee80211_ch_switch_timing)];

        /* initial timing are always zero in the template */
        iee80211_tdls_add_ch_switch_timing(extra_ies, 0, 0);

        skb = ieee80211_tdls_build_mgmt_packet_data(sdata, sta->sta.addr,
                                        WLAN_TDLS_CHANNEL_SWITCH_RESPONSE,
                                        0, 0, !sta->sta.tdls_initiator,
                                        extra_ies, sizeof(extra_ies), 0, NULL);
        if (!skb)
                return NULL;

        skb = ieee80211_build_data_template(sdata, skb, 0);
        if (IS_ERR(skb)) {
                tdls_dbg(sdata,
                         "Failed building TDLS channel switch resp frame\n");
                return NULL;
        }

        if (ch_sw_tm_ie_offset) {
                const u8 *tm_ie = ieee80211_tdls_find_sw_timing_ie(skb);

                if (!tm_ie) {
                        tdls_dbg(sdata,
                                 "No switch timing IE in TDLS switch resp\n");
                        dev_kfree_skb_any(skb);
                        return NULL;
                }

                *ch_sw_tm_ie_offset = tm_ie - skb->data;
        }

        tdls_dbg(sdata, "TDLS get channel switch response template for %pM\n",
                 sta->sta.addr);
        return skb;
}

static int
ieee80211_process_tdls_channel_switch_resp(struct ieee80211_sub_if_data *sdata,
                                           struct sk_buff *skb)
{
        struct ieee80211_local *local = sdata->local;
        struct ieee802_11_elems elems;
        struct sta_info *sta;
        struct ieee80211_tdls_data *tf = (void *)skb->data;
        bool local_initiator;
        struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
        int baselen = offsetof(typeof(*tf), u.chan_switch_resp.variable);
        struct ieee80211_tdls_ch_sw_params params = {};
        int ret;

        params.action_code = WLAN_TDLS_CHANNEL_SWITCH_RESPONSE;
        params.timestamp = rx_status->device_timestamp;

        if (skb->len < baselen) {
                tdls_dbg(sdata, "TDLS channel switch resp too short: %d\n",
                         skb->len);
                return -EINVAL;
        }

        mutex_lock(&local->sta_mtx);
        sta = sta_info_get(sdata, tf->sa);
        if (!sta || !test_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH)) {
                tdls_dbg(sdata, "TDLS chan switch from non-peer sta %pM\n",
                         tf->sa);
                ret = -EINVAL;
                goto out;
        }

        params.sta = &sta->sta;
        params.status = le16_to_cpu(tf->u.chan_switch_resp.status_code);
        if (params.status != 0) {
                ret = 0;
                goto call_drv;
        }

        ieee802_11_parse_elems(tf->u.chan_switch_resp.variable,
                               skb->len - baselen, false, &elems);
        if (elems.parse_error) {
                tdls_dbg(sdata, "Invalid IEs in TDLS channel switch resp\n");
                ret = -EINVAL;
                goto out;
        }

        if (!elems.ch_sw_timing || !elems.lnk_id) {
                tdls_dbg(sdata, "TDLS channel switch resp - missing IEs\n");
                ret = -EINVAL;
                goto out;
        }

        /* validate the initiator is set correctly */
        local_initiator =
                !memcmp(elems.lnk_id->init_sta, sdata->vif.addr, ETH_ALEN);
        if (local_initiator == sta->sta.tdls_initiator) {
                tdls_dbg(sdata, "TDLS chan switch invalid lnk-id initiator\n");
                ret = -EINVAL;
                goto out;
        }

        params.switch_time = le16_to_cpu(elems.ch_sw_timing->switch_time);
        params.switch_timeout = le16_to_cpu(elems.ch_sw_timing->switch_timeout);

        params.tmpl_skb =
                ieee80211_tdls_ch_sw_resp_tmpl_get(sta, &params.ch_sw_tm_ie);
        if (!params.tmpl_skb) {
                ret = -ENOENT;
                goto out;
        }

call_drv:
        drv_tdls_recv_channel_switch(sdata->local, sdata, &params);

        tdls_dbg(sdata,
                 "TDLS channel switch response received from %pM status %d\n",
                 tf->sa, params.status);

out:
        mutex_unlock(&local->sta_mtx);
        dev_kfree_skb_any(params.tmpl_skb);
        return ret;
}

static int
ieee80211_process_tdls_channel_switch_req(struct ieee80211_sub_if_data *sdata,
                                          struct sk_buff *skb)
{
        struct ieee80211_local *local = sdata->local;
        struct ieee802_11_elems elems;
        struct cfg80211_chan_def chandef;
        struct ieee80211_channel *chan;
        enum nl80211_channel_type chan_type;
        int freq;
        u8 target_channel, oper_class;
        bool local_initiator;
        struct sta_info *sta;
        enum ieee80211_band band;
        struct ieee80211_tdls_data *tf = (void *)skb->data;
        struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb);
        int baselen = offsetof(typeof(*tf), u.chan_switch_req.variable);
        struct ieee80211_tdls_ch_sw_params params = {};
        int ret = 0;

        params.action_code = WLAN_TDLS_CHANNEL_SWITCH_REQUEST;
        params.timestamp = rx_status->device_timestamp;

        if (skb->len < baselen) {
                tdls_dbg(sdata, "TDLS channel switch req too short: %d\n",
                         skb->len);
                return -EINVAL;
        }

        target_channel = tf->u.chan_switch_req.target_channel;
        oper_class = tf->u.chan_switch_req.oper_class;

        /*
         * We can't easily infer the channel band. The operating class is
         * ambiguous - there are multiple tables (US/Europe/JP/Global). The
         * solution here is to treat channels with number >14 as 5GHz ones,
         * and specifically check for the (oper_class, channel) combinations
         * where this doesn't hold. These are thankfully unique according to
         * IEEE802.11-2012.
         * We consider only the 2GHz and 5GHz bands and 20MHz+ channels as
         * valid here.
         */
        if ((oper_class == 112 || oper_class == 2 || oper_class == 3 ||
             oper_class == 4 || oper_class == 5 || oper_class == 6) &&
             target_channel < 14)
                band = IEEE80211_BAND_5GHZ;
        else
                band = target_channel < 14 ? IEEE80211_BAND_2GHZ :
                                             IEEE80211_BAND_5GHZ;

        freq = ieee80211_channel_to_frequency(target_channel, band);
        if (freq == 0) {
                tdls_dbg(sdata, "Invalid channel in TDLS chan switch: %d\n",
                         target_channel);
                return -EINVAL;
        }

        chan = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
        if (!chan) {
                tdls_dbg(sdata,
                         "Unsupported channel for TDLS chan switch: %d\n",
                         target_channel);
                return -EINVAL;
        }

        ieee802_11_parse_elems(tf->u.chan_switch_req.variable,
                               skb->len - baselen, false, &elems);
        if (elems.parse_error) {
                tdls_dbg(sdata, "Invalid IEs in TDLS channel switch req\n");
                return -EINVAL;
        }

        if (!elems.ch_sw_timing || !elems.lnk_id) {
                tdls_dbg(sdata, "TDLS channel switch req - missing IEs\n");
                return -EINVAL;
        }

        mutex_lock(&local->sta_mtx);
        sta = sta_info_get(sdata, tf->sa);
        if (!sta || !test_sta_flag(sta, WLAN_STA_TDLS_PEER_AUTH)) {
                tdls_dbg(sdata, "TDLS chan switch from non-peer sta %pM\n",
                         tf->sa);
                ret = -EINVAL;
                goto out;
        }

        params.sta = &sta->sta;

        /* validate the initiator is set correctly */
        local_initiator =
                !memcmp(elems.lnk_id->init_sta, sdata->vif.addr, ETH_ALEN);
        if (local_initiator == sta->sta.tdls_initiator) {
                tdls_dbg(sdata, "TDLS chan switch invalid lnk-id initiator\n");
                ret = -EINVAL;
                goto out;
        }

        if (!sta->sta.ht_cap.ht_supported) {
                chan_type = NL80211_CHAN_NO_HT;
        } else if (!elems.sec_chan_offs) {
                chan_type = NL80211_CHAN_HT20;
        } else {
                switch (elems.sec_chan_offs->sec_chan_offs) {
                case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
                        chan_type = NL80211_CHAN_HT40PLUS;
                        break;
                case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
                        chan_type = NL80211_CHAN_HT40MINUS;
                        break;
                default:
                        chan_type = NL80211_CHAN_HT20;
                        break;
                }
        }

        cfg80211_chandef_create(&chandef, chan, chan_type);
        params.chandef = &chandef;

        params.switch_time = le16_to_cpu(elems.ch_sw_timing->switch_time);
        params.switch_timeout = le16_to_cpu(elems.ch_sw_timing->switch_timeout);

        params.tmpl_skb =
                ieee80211_tdls_ch_sw_resp_tmpl_get(sta,
                                                   &params.ch_sw_tm_ie);
        if (!params.tmpl_skb) {
                ret = -ENOENT;
                goto out;
        }

        drv_tdls_recv_channel_switch(sdata->local, sdata, &params);

        tdls_dbg(sdata,
                 "TDLS ch switch request received from %pM ch %d width %d\n",
                 tf->sa, params.chandef->chan->center_freq,
                 params.chandef->width);
out:
        mutex_unlock(&local->sta_mtx);
        dev_kfree_skb_any(params.tmpl_skb);
        return ret;
}

void ieee80211_process_tdls_channel_switch(struct ieee80211_sub_if_data *sdata,
                                           struct sk_buff *skb)
{
        struct ieee80211_tdls_data *tf = (void *)skb->data;
        struct wiphy *wiphy = sdata->local->hw.wiphy;

        /* make sure the driver supports it */
        if (!(wiphy->features & NL80211_FEATURE_TDLS_CHANNEL_SWITCH))
                return;

        /* we want to access the entire packet */
        if (skb_linearize(skb))
                return;
        /*
         * The packet/size was already validated by mac80211 Rx path, only look
         * at the action type.
         */
        switch (tf->action_code) {
        case WLAN_TDLS_CHANNEL_SWITCH_REQUEST:
                ieee80211_process_tdls_channel_switch_req(sdata, skb);
                break;
        case WLAN_TDLS_CHANNEL_SWITCH_RESPONSE:
                ieee80211_process_tdls_channel_switch_resp(sdata, skb);
                break;
        default:
                WARN_ON_ONCE(1);
                return;
        }
}