// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2004, Instant802 Networks, Inc.
 * Copyright 2013-2014  Intel Mobile Communications GmbH
 * Copyright (C) 2022 Intel Corporation
 */

#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/module.h>
#include <linux/if_arp.h>
#include <linux/types.h>
#include <net/ip.h>
#include <net/pkt_sched.h>

#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "wme.h"

/* Default mapping in classifier to work with default
 * queue setup.
 */
const int ieee802_1d_to_ac[8] = {
        IEEE80211_AC_BE,
        IEEE80211_AC_BK,
        IEEE80211_AC_BK,
        IEEE80211_AC_BE,
        IEEE80211_AC_VI,
        IEEE80211_AC_VI,
        IEEE80211_AC_VO,
        IEEE80211_AC_VO
};

static int wme_downgrade_ac(struct sk_buff *skb)
{
        switch (skb->priority) {
        case 6:
        case 7:
                skb->priority = 5; /* VO -> VI */
                return 0;
        case 4:
        case 5:
                skb->priority = 3; /* VI -> BE */
                return 0;
        case 0:
        case 3:
                skb->priority = 2; /* BE -> BK */
                return 0;
        default:
                return -1;
        }
}

/**
 * ieee80211_fix_reserved_tid - return the TID to use if this one is reserved
 * @tid: the assumed-reserved TID
 *
 * Returns: the alternative TID to use, or 0 on error
 */
static inline u8 ieee80211_fix_reserved_tid(u8 tid)
{
        switch (tid) {
        case 0:
                return 3;
        case 1:
                return 2;
        case 2:
                return 1;
        case 3:
                return 0;
        case 4:
                return 5;
        case 5:
                return 4;
        case 6:
                return 7;
        case 7:
                return 6;
        }

        return 0;
}

static u16 ieee80211_downgrade_queue(struct ieee80211_sub_if_data *sdata,
                                     struct sta_info *sta, struct sk_buff *skb)
{
        struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;

        /* in case we are a client verify acm is not set for this ac */
        while (sdata->wmm_acm & BIT(skb->priority)) {
                int ac = ieee802_1d_to_ac[skb->priority];

                if (ifmgd->tx_tspec[ac].admitted_time &&
                    skb->priority == ifmgd->tx_tspec[ac].up)
                        return ac;

                if (wme_downgrade_ac(skb)) {
                        /*
                         * This should not really happen. The AP has marked all
                         * lower ACs to require admission control which is not
                         * a reasonable configuration. Allow the frame to be
                         * transmitted using AC_BK as a workaround.
                         */
                        break;
                }
        }

        /* Check to see if this is a reserved TID */
        if (sta && sta->reserved_tid == skb->priority)
                skb->priority = ieee80211_fix_reserved_tid(skb->priority);

        /* look up which queue to use for frames with this 1d tag */
        return ieee802_1d_to_ac[skb->priority];
}

/* Indicate which queue to use for this fully formed 802.11 frame */
u16 ieee80211_select_queue_80211(struct ieee80211_sub_if_data *sdata,
                                 struct sk_buff *skb,
                                 struct ieee80211_hdr *hdr)
{
        struct ieee80211_local *local = sdata->local;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        u8 *p;

        /* Ensure hash is set prior to potential SW encryption */
        skb_get_hash(skb);

        if ((info->control.flags & IEEE80211_TX_CTRL_DONT_REORDER) ||
            local->hw.queues < IEEE80211_NUM_ACS)
                return 0;

        if (!ieee80211_is_data(hdr->frame_control)) {
                skb->priority = 7;
                return ieee802_1d_to_ac[skb->priority];
        }
        if (!ieee80211_is_data_qos(hdr->frame_control)) {
                skb->priority = 0;
                return ieee802_1d_to_ac[skb->priority];
        }

        p = ieee80211_get_qos_ctl(hdr);
        skb->priority = *p & IEEE80211_QOS_CTL_TAG1D_MASK;

        return ieee80211_downgrade_queue(sdata, NULL, skb);
}

u16 ieee80211_select_queue(struct ieee80211_sub_if_data *sdata,
                           struct sta_info *sta, struct sk_buff *skb)
{
        const struct ethhdr *eth = (void *)skb->data;
        struct mac80211_qos_map *qos_map;
        bool qos;

        /* Ensure hash is set prior to potential SW encryption */
        skb_get_hash(skb);

        /* all mesh/ocb stations are required to support WME */
        if ((sdata->vif.type == NL80211_IFTYPE_MESH_POINT &&
            !is_multicast_ether_addr(eth->h_dest)) ||
            (sdata->vif.type == NL80211_IFTYPE_OCB && sta))
                qos = true;
        else if (sta)
                qos = sta->sta.wme;
        else
                qos = false;

        if (!qos) {
                skb->priority = 0; /* required for correct WPA/11i MIC */
                return IEEE80211_AC_BE;
        }

        if (skb->protocol == sdata->control_port_protocol) {
                skb->priority = 7;
                goto downgrade;
        }

        /* use the data classifier to determine what 802.1d tag the
         * data frame has */
        qos_map = rcu_dereference(sdata->qos_map);
        skb->priority = cfg80211_classify8021d(skb, qos_map ?
                                               &qos_map->qos_map : NULL);

 downgrade:
        return ieee80211_downgrade_queue(sdata, sta, skb);
}

/**
 * ieee80211_set_qos_hdr - Fill in the QoS header if there is one.
 *
 * @sdata: local subif
 * @skb: packet to be updated
 */
void ieee80211_set_qos_hdr(struct ieee80211_sub_if_data *sdata,
                           struct sk_buff *skb)
{
        struct ieee80211_hdr *hdr = (void *)skb->data;
        struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
        u8 tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
        u8 flags;
        u8 *p;

        if (!ieee80211_is_data_qos(hdr->frame_control))
                return;

        p = ieee80211_get_qos_ctl(hdr);

        /* don't overwrite the QoS field of injected frames */
        if (info->flags & IEEE80211_TX_CTL_INJECTED) {
                /* do take into account Ack policy of injected frames */
                if (*p & IEEE80211_QOS_CTL_ACK_POLICY_NOACK)
                        info->flags |= IEEE80211_TX_CTL_NO_ACK;
                return;
        }

        /* set up the first byte */

        /*
         * preserve everything but the TID and ACK policy
         * (which we both write here)
         */
        flags = *p & ~(IEEE80211_QOS_CTL_TID_MASK |
                       IEEE80211_QOS_CTL_ACK_POLICY_MASK);

        if (is_multicast_ether_addr(hdr->addr1) ||
            sdata->noack_map & BIT(tid)) {
                flags |= IEEE80211_QOS_CTL_ACK_POLICY_NOACK;
                info->flags |= IEEE80211_TX_CTL_NO_ACK;
        }

        *p = flags | tid;

        /* set up the second byte */
        p++;

        if (ieee80211_vif_is_mesh(&sdata->vif)) {
                /* preserve RSPI and Mesh PS Level bit */
                *p &= ((IEEE80211_QOS_CTL_RSPI |
                        IEEE80211_QOS_CTL_MESH_PS_LEVEL) >> 8);

                /* Nulls don't have a mesh header (frame body) */
                if (!ieee80211_is_qos_nullfunc(hdr->frame_control))
                        *p |= (IEEE80211_QOS_CTL_MESH_CONTROL_PRESENT >> 8);
        } else {
                *p = 0;
        }
}