#include <linux/etherdevice.h>
#include <net/ieee80211_crypt.h>

#include "hostap_80211.h"
#include "hostap.h"
#include "hostap_ap.h"

/* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
/* Ethernet-II snap header (RFC1042 for most EtherTypes) */
static unsigned char rfc1042_header[] =
{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
/* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
static unsigned char bridge_tunnel_header[] =
{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
/* No encapsulation header if EtherType < 0x600 (=length) */

void hostap_dump_rx_80211(const char *name, struct sk_buff *skb,
                          struct hostap_80211_rx_status *rx_stats)
{
        struct ieee80211_hdr_4addr *hdr;
        u16 fc;
        DECLARE_MAC_BUF(mac);

        hdr = (struct ieee80211_hdr_4addr *) skb->data;

        printk(KERN_DEBUG "%s: RX signal=%d noise=%d rate=%d len=%d "
               "jiffies=%ld\n",
               name, rx_stats->signal, rx_stats->noise, rx_stats->rate,
               skb->len, jiffies);

        if (skb->len < 2)
                return;

        fc = le16_to_cpu(hdr->frame_ctl);
        printk(KERN_DEBUG "   FC=0x%04x (type=%d:%d)%s%s",
               fc, WLAN_FC_GET_TYPE(fc) >> 2, WLAN_FC_GET_STYPE(fc) >> 4,
               fc & IEEE80211_FCTL_TODS ? " [ToDS]" : "",
               fc & IEEE80211_FCTL_FROMDS ? " [FromDS]" : "");

        if (skb->len < IEEE80211_DATA_HDR3_LEN) {
                printk("\n");
                return;
        }

        printk(" dur=0x%04x seq=0x%04x\n", le16_to_cpu(hdr->duration_id),
               le16_to_cpu(hdr->seq_ctl));

        printk(KERN_DEBUG "   A1=%s", print_mac(mac, hdr->addr1));
        printk(" A2=%s", print_mac(mac, hdr->addr2));
        printk(" A3=%s", print_mac(mac, hdr->addr3));
        if (skb->len >= 30)
                printk(" A4=%s", print_mac(mac, hdr->addr4));
        printk("\n");
}


/* Send RX frame to netif with 802.11 (and possible prism) header.
 * Called from hardware or software IRQ context. */
int prism2_rx_80211(struct net_device *dev, struct sk_buff *skb,
                    struct hostap_80211_rx_status *rx_stats, int type)
{
        struct hostap_interface *iface;
        local_info_t *local;
        int hdrlen, phdrlen, head_need, tail_need;
        u16 fc;
        int prism_header, ret;
        struct ieee80211_hdr_4addr *hdr;

        iface = netdev_priv(dev);
        local = iface->local;
        dev->last_rx = jiffies;

        if (dev->type == ARPHRD_IEEE80211_PRISM) {
                if (local->monitor_type == PRISM2_MONITOR_PRISM) {
                        prism_header = 1;
                        phdrlen = sizeof(struct linux_wlan_ng_prism_hdr);
                } else { /* local->monitor_type == PRISM2_MONITOR_CAPHDR */
                        prism_header = 2;
                        phdrlen = sizeof(struct linux_wlan_ng_cap_hdr);
                }
        } else {
                prism_header = 0;
                phdrlen = 0;
        }

        hdr = (struct ieee80211_hdr_4addr *) skb->data;
        fc = le16_to_cpu(hdr->frame_ctl);

        if (type == PRISM2_RX_MGMT && (fc & IEEE80211_FCTL_VERS)) {
                printk(KERN_DEBUG "%s: dropped management frame with header "
                       "version %d\n", dev->name, fc & IEEE80211_FCTL_VERS);
                dev_kfree_skb_any(skb);
                return 0;
        }

        hdrlen = hostap_80211_get_hdrlen(fc);

        /* check if there is enough room for extra data; if not, expand skb
         * buffer to be large enough for the changes */
        head_need = phdrlen;
        tail_need = 0;
#ifdef PRISM2_ADD_BOGUS_CRC
        tail_need += 4;
#endif /* PRISM2_ADD_BOGUS_CRC */

        head_need -= skb_headroom(skb);
        tail_need -= skb_tailroom(skb);

        if (head_need > 0 || tail_need > 0) {
                if (pskb_expand_head(skb, head_need > 0 ? head_need : 0,
                                     tail_need > 0 ? tail_need : 0,
                                     GFP_ATOMIC)) {
                        printk(KERN_DEBUG "%s: prism2_rx_80211 failed to "
                               "reallocate skb buffer\n", dev->name);
                        dev_kfree_skb_any(skb);
                        return 0;
                }
        }

        /* We now have an skb with enough head and tail room, so just insert
         * the extra data */

#ifdef PRISM2_ADD_BOGUS_CRC
        memset(skb_put(skb, 4), 0xff, 4); /* Prism2 strips CRC */
#endif /* PRISM2_ADD_BOGUS_CRC */

        if (prism_header == 1) {
                struct linux_wlan_ng_prism_hdr *hdr;
                hdr = (struct linux_wlan_ng_prism_hdr *)
                        skb_push(skb, phdrlen);
                memset(hdr, 0, phdrlen);
                hdr->msgcode = LWNG_CAP_DID_BASE;
                hdr->msglen = sizeof(*hdr);
                memcpy(hdr->devname, dev->name, sizeof(hdr->devname));
#define LWNG_SETVAL(f,i,s,l,d) \
hdr->f.did = LWNG_CAP_DID_BASE | (i << 12); \
hdr->f.status = s; hdr->f.len = l; hdr->f.data = d
                LWNG_SETVAL(hosttime, 1, 0, 4, jiffies);
                LWNG_SETVAL(mactime, 2, 0, 4, rx_stats->mac_time);
                LWNG_SETVAL(channel, 3, 1 /* no value */, 4, 0);
                LWNG_SETVAL(rssi, 4, 1 /* no value */, 4, 0);
                LWNG_SETVAL(sq, 5, 1 /* no value */, 4, 0);
                LWNG_SETVAL(signal, 6, 0, 4, rx_stats->signal);
                LWNG_SETVAL(noise, 7, 0, 4, rx_stats->noise);
                LWNG_SETVAL(rate, 8, 0, 4, rx_stats->rate / 5);
                LWNG_SETVAL(istx, 9, 0, 4, 0);
                LWNG_SETVAL(frmlen, 10, 0, 4, skb->len - phdrlen);
#undef LWNG_SETVAL
        } else if (prism_header == 2) {
                struct linux_wlan_ng_cap_hdr *hdr;
                hdr = (struct linux_wlan_ng_cap_hdr *)
                        skb_push(skb, phdrlen);
                memset(hdr, 0, phdrlen);
                hdr->version    = htonl(LWNG_CAPHDR_VERSION);
                hdr->length     = htonl(phdrlen);
                hdr->mactime    = __cpu_to_be64(rx_stats->mac_time);
                hdr->hosttime   = __cpu_to_be64(jiffies);
                hdr->phytype    = htonl(4); /* dss_dot11_b */
                hdr->channel    = htonl(local->channel);
                hdr->datarate   = htonl(rx_stats->rate);
                hdr->antenna    = htonl(0); /* unknown */
                hdr->priority   = htonl(0); /* unknown */
                hdr->ssi_type   = htonl(3); /* raw */
                hdr->ssi_signal = htonl(rx_stats->signal);
                hdr->ssi_noise  = htonl(rx_stats->noise);
                hdr->preamble   = htonl(0); /* unknown */
                hdr->encoding   = htonl(1); /* cck */
        }

        ret = skb->len - phdrlen;
        skb->dev = dev;
        skb_reset_mac_header(skb);
        skb_pull(skb, hdrlen);
        if (prism_header)
                skb_pull(skb, phdrlen);
        skb->pkt_type = PACKET_OTHERHOST;
        skb->protocol = __constant_htons(ETH_P_802_2);
        memset(skb->cb, 0, sizeof(skb->cb));
        netif_rx(skb);

        return ret;
}


/* Called only as a tasklet (software IRQ) */
static void monitor_rx(struct net_device *dev, struct sk_buff *skb,
                       struct hostap_80211_rx_status *rx_stats)
{
        struct net_device_stats *stats;
        int len;

        len = prism2_rx_80211(dev, skb, rx_stats, PRISM2_RX_MONITOR);
        stats = hostap_get_stats(dev);
        stats->rx_packets++;
        stats->rx_bytes += len;
}


/* Called only as a tasklet (software IRQ) */
static struct prism2_frag_entry *
prism2_frag_cache_find(local_info_t *local, unsigned int seq,
                       unsigned int frag, u8 *src, u8 *dst)
{
        struct prism2_frag_entry *entry;
        int i;

        for (i = 0; i < PRISM2_FRAG_CACHE_LEN; i++) {
                entry = &local->frag_cache[i];
                if (entry->skb != NULL &&
                    time_after(jiffies, entry->first_frag_time + 2 * HZ)) {
                        printk(KERN_DEBUG "%s: expiring fragment cache entry "
                               "seq=%u last_frag=%u\n",
                               local->dev->name, entry->seq, entry->last_frag);
                        dev_kfree_skb(entry->skb);
                        entry->skb = NULL;
                }

                if (entry->skb != NULL && entry->seq == seq &&
                    (entry->last_frag + 1 == frag || frag == -1) &&
                    memcmp(entry->src_addr, src, ETH_ALEN) == 0 &&
                    memcmp(entry->dst_addr, dst, ETH_ALEN) == 0)
                        return entry;
        }

        return NULL;
}


/* Called only as a tasklet (software IRQ) */
static struct sk_buff *
prism2_frag_cache_get(local_info_t *local, struct ieee80211_hdr_4addr *hdr)
{
        struct sk_buff *skb = NULL;
        u16 sc;
        unsigned int frag, seq;
        struct prism2_frag_entry *entry;

        sc = le16_to_cpu(hdr->seq_ctl);
        frag = WLAN_GET_SEQ_FRAG(sc);
        seq = WLAN_GET_SEQ_SEQ(sc) >> 4;

        if (frag == 0) {
                /* Reserve enough space to fit maximum frame length */
                skb = dev_alloc_skb(local->dev->mtu +
                                    sizeof(struct ieee80211_hdr_4addr) +
                                    8 /* LLC */ +
                                    2 /* alignment */ +
                                    8 /* WEP */ + ETH_ALEN /* WDS */);
                if (skb == NULL)
                        return NULL;

                entry = &local->frag_cache[local->frag_next_idx];
                local->frag_next_idx++;
                if (local->frag_next_idx >= PRISM2_FRAG_CACHE_LEN)
                        local->frag_next_idx = 0;

                if (entry->skb != NULL)
                        dev_kfree_skb(entry->skb);

                entry->first_frag_time = jiffies;
                entry->seq = seq;
                entry->last_frag = frag;
                entry->skb = skb;
                memcpy(entry->src_addr, hdr->addr2, ETH_ALEN);
                memcpy(entry->dst_addr, hdr->addr1, ETH_ALEN);
        } else {
                /* received a fragment of a frame for which the head fragment
                 * should have already been received */
                entry = prism2_frag_cache_find(local, seq, frag, hdr->addr2,
                                               hdr->addr1);
                if (entry != NULL) {
                        entry->last_frag = frag;
                        skb = entry->skb;
                }
        }

        return skb;
}


/* Called only as a tasklet (software IRQ) */
static int prism2_frag_cache_invalidate(local_info_t *local,
                                        struct ieee80211_hdr_4addr *hdr)
{
        u16 sc;
        unsigned int seq;
        struct prism2_frag_entry *entry;

        sc = le16_to_cpu(hdr->seq_ctl);
        seq = WLAN_GET_SEQ_SEQ(sc) >> 4;

        entry = prism2_frag_cache_find(local, seq, -1, hdr->addr2, hdr->addr1);

        if (entry == NULL) {
                printk(KERN_DEBUG "%s: could not invalidate fragment cache "
                       "entry (seq=%u)\n",
                       local->dev->name, seq);
                return -1;
        }

        entry->skb = NULL;
        return 0;
}


static struct hostap_bss_info *__hostap_get_bss(local_info_t *local, u8 *bssid,
                                                u8 *ssid, size_t ssid_len)
{
        struct list_head *ptr;
        struct hostap_bss_info *bss;

        list_for_each(ptr, &local->bss_list) {
                bss = list_entry(ptr, struct hostap_bss_info, list);
                if (memcmp(bss->bssid, bssid, ETH_ALEN) == 0 &&
                    (ssid == NULL ||
                     (ssid_len == bss->ssid_len &&
                      memcmp(ssid, bss->ssid, ssid_len) == 0))) {
                        list_move(&bss->list, &local->bss_list);
                        return bss;
                }
        }

        return NULL;
}


static struct hostap_bss_info *__hostap_add_bss(local_info_t *local, u8 *bssid,
                                                u8 *ssid, size_t ssid_len)
{
        struct hostap_bss_info *bss;

        if (local->num_bss_info >= HOSTAP_MAX_BSS_COUNT) {
                bss = list_entry(local->bss_list.prev,
                                 struct hostap_bss_info, list);
                list_del(&bss->list);
                local->num_bss_info--;
        } else {
                bss = (struct hostap_bss_info *)
                        kmalloc(sizeof(*bss), GFP_ATOMIC);
                if (bss == NULL)
                        return NULL;
        }

        memset(bss, 0, sizeof(*bss));
        memcpy(bss->bssid, bssid, ETH_ALEN);
        memcpy(bss->ssid, ssid, ssid_len);
        bss->ssid_len = ssid_len;
        local->num_bss_info++;
        list_add(&bss->list, &local->bss_list);
        return bss;
}


static void __hostap_expire_bss(local_info_t *local)
{
        struct hostap_bss_info *bss;

        while (local->num_bss_info > 0) {
                bss = list_entry(local->bss_list.prev,
                                 struct hostap_bss_info, list);
                if (!time_after(jiffies, bss->last_update + 60 * HZ))
                        break;

                list_del(&bss->list);
                local->num_bss_info--;
                kfree(bss);
        }
}


/* Both IEEE 802.11 Beacon and Probe Response frames have similar structure, so
 * the same routine can be used to parse both of them. */
static void hostap_rx_sta_beacon(local_info_t *local, struct sk_buff *skb,
                                 int stype)
{
        struct hostap_ieee80211_mgmt *mgmt;
        int left, chan = 0;
        u8 *pos;
        u8 *ssid = NULL, *wpa = NULL, *rsn = NULL;
        size_t ssid_len = 0, wpa_len = 0, rsn_len = 0;
        struct hostap_bss_info *bss;

        if (skb->len < IEEE80211_MGMT_HDR_LEN + sizeof(mgmt->u.beacon))
                return;

        mgmt = (struct hostap_ieee80211_mgmt *) skb->data;
        pos = mgmt->u.beacon.variable;
        left = skb->len - (pos - skb->data);

        while (left >= 2) {
                if (2 + pos[1] > left)
                        return; /* parse failed */
                switch (*pos) {
                case WLAN_EID_SSID:
                        ssid = pos + 2;
                        ssid_len = pos[1];
                        break;
                case WLAN_EID_GENERIC:
                        if (pos[1] >= 4 &&
                            pos[2] == 0x00 && pos[3] == 0x50 &&
                            pos[4] == 0xf2 && pos[5] == 1) {
                                wpa = pos;
                                wpa_len = pos[1] + 2;
                        }
                        break;
                case WLAN_EID_RSN:
                        rsn = pos;
                        rsn_len = pos[1] + 2;
                        break;
                case WLAN_EID_DS_PARAMS:
                        if (pos[1] >= 1)
                                chan = pos[2];
                        break;
                }
                left -= 2 + pos[1];
                pos += 2 + pos[1];
        }

        if (wpa_len > MAX_WPA_IE_LEN)
                wpa_len = MAX_WPA_IE_LEN;
        if (rsn_len > MAX_WPA_IE_LEN)
                rsn_len = MAX_WPA_IE_LEN;
        if (ssid_len > sizeof(bss->ssid))
                ssid_len = sizeof(bss->ssid);

        spin_lock(&local->lock);
        bss = __hostap_get_bss(local, mgmt->bssid, ssid, ssid_len);
        if (bss == NULL)
                bss = __hostap_add_bss(local, mgmt->bssid, ssid, ssid_len);
        if (bss) {
                bss->last_update = jiffies;
                bss->count++;
                bss->capab_info = le16_to_cpu(mgmt->u.beacon.capab_info);
                if (wpa) {
                        memcpy(bss->wpa_ie, wpa, wpa_len);
                        bss->wpa_ie_len = wpa_len;
                } else
                        bss->wpa_ie_len = 0;
                if (rsn) {
                        memcpy(bss->rsn_ie, rsn, rsn_len);
                        bss->rsn_ie_len = rsn_len;
                } else
                        bss->rsn_ie_len = 0;
                bss->chan = chan;
        }
        __hostap_expire_bss(local);
        spin_unlock(&local->lock);
}


static int
hostap_rx_frame_mgmt(local_info_t *local, struct sk_buff *skb,
                     struct hostap_80211_rx_status *rx_stats, u16 type,
                     u16 stype)
{
        if (local->iw_mode == IW_MODE_MASTER) {
                hostap_update_sta_ps(local, (struct ieee80211_hdr_4addr *)
                                     skb->data);
        }

        if (local->hostapd && type == IEEE80211_FTYPE_MGMT) {
                if (stype == IEEE80211_STYPE_BEACON &&
                    local->iw_mode == IW_MODE_MASTER) {
                        struct sk_buff *skb2;
                        /* Process beacon frames also in kernel driver to
                         * update STA(AP) table statistics */
                        skb2 = skb_clone(skb, GFP_ATOMIC);
                        if (skb2)
                                hostap_rx(skb2->dev, skb2, rx_stats);
                }

                /* send management frames to the user space daemon for
                 * processing */
                local->apdevstats.rx_packets++;
                local->apdevstats.rx_bytes += skb->len;
                if (local->apdev == NULL)
                        return -1;
                prism2_rx_80211(local->apdev, skb, rx_stats, PRISM2_RX_MGMT);
                return 0;
        }

        if (local->iw_mode == IW_MODE_MASTER) {
                if (type != IEEE80211_FTYPE_MGMT &&
                    type != IEEE80211_FTYPE_CTL) {
                        printk(KERN_DEBUG "%s: unknown management frame "
                               "(type=0x%02x, stype=0x%02x) dropped\n",
                               skb->dev->name, type >> 2, stype >> 4);
                        return -1;
                }

                hostap_rx(skb->dev, skb, rx_stats);
                return 0;
        } else if (type == IEEE80211_FTYPE_MGMT &&
                   (stype == IEEE80211_STYPE_BEACON ||
                    stype == IEEE80211_STYPE_PROBE_RESP)) {
                hostap_rx_sta_beacon(local, skb, stype);
                return -1;
        } else if (type == IEEE80211_FTYPE_MGMT &&
                   (stype == IEEE80211_STYPE_ASSOC_RESP ||
                    stype == IEEE80211_STYPE_REASSOC_RESP)) {
                /* Ignore (Re)AssocResp silently since these are not currently
                 * needed but are still received when WPA/RSN mode is enabled.
                 */
                return -1;
        } else {
                printk(KERN_DEBUG "%s: hostap_rx_frame_mgmt: dropped unhandled"
                       " management frame in non-Host AP mode (type=%d:%d)\n",
                       skb->dev->name, type >> 2, stype >> 4);
                return -1;
        }
}


/* Called only as a tasklet (software IRQ) */
static struct net_device *prism2_rx_get_wds(local_info_t *local,
                                                   u8 *addr)
{
        struct hostap_interface *iface = NULL;
        struct list_head *ptr;

        read_lock_bh(&local->iface_lock);
        list_for_each(ptr, &local->hostap_interfaces) {
                iface = list_entry(ptr, struct hostap_interface, list);
                if (iface->type == HOSTAP_INTERFACE_WDS &&
                    memcmp(iface->u.wds.remote_addr, addr, ETH_ALEN) == 0)
                        break;
                iface = NULL;
        }
        read_unlock_bh(&local->iface_lock);

        return iface ? iface->dev : NULL;
}


static int
hostap_rx_frame_wds(local_info_t *local, struct ieee80211_hdr_4addr *hdr,
                    u16 fc, struct net_device **wds)
{
        DECLARE_MAC_BUF(mac);
        /* FIX: is this really supposed to accept WDS frames only in Master
         * mode? What about Repeater or Managed with WDS frames? */
        if ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) !=
            (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS) &&
            (local->iw_mode != IW_MODE_MASTER || !(fc & IEEE80211_FCTL_TODS)))
                return 0; /* not a WDS frame */

        /* Possible WDS frame: either IEEE 802.11 compliant (if FromDS)
         * or own non-standard frame with 4th address after payload */
        if (memcmp(hdr->addr1, local->dev->dev_addr, ETH_ALEN) != 0 &&
            (hdr->addr1[0] != 0xff || hdr->addr1[1] != 0xff ||
             hdr->addr1[2] != 0xff || hdr->addr1[3] != 0xff ||
             hdr->addr1[4] != 0xff || hdr->addr1[5] != 0xff)) {
                /* RA (or BSSID) is not ours - drop */
                PDEBUG(DEBUG_EXTRA, "%s: received WDS frame with "
                       "not own or broadcast %s=%s\n",
                       local->dev->name,
                       fc & IEEE80211_FCTL_FROMDS ? "RA" : "BSSID",
                       print_mac(mac, hdr->addr1));
                return -1;
        }

        /* check if the frame came from a registered WDS connection */
        *wds = prism2_rx_get_wds(local, hdr->addr2);
        if (*wds == NULL && fc & IEEE80211_FCTL_FROMDS &&
            (local->iw_mode != IW_MODE_INFRA ||
             !(local->wds_type & HOSTAP_WDS_AP_CLIENT) ||
             memcmp(hdr->addr2, local->bssid, ETH_ALEN) != 0)) {
                /* require that WDS link has been registered with TA or the
                 * frame is from current AP when using 'AP client mode' */
                PDEBUG(DEBUG_EXTRA, "%s: received WDS[4 addr] frame "
                       "from unknown TA=%s\n",
                       local->dev->name, print_mac(mac, hdr->addr2));
                if (local->ap && local->ap->autom_ap_wds)
                        hostap_wds_link_oper(local, hdr->addr2, WDS_ADD);
                return -1;
        }

        if (*wds && !(fc & IEEE80211_FCTL_FROMDS) && local->ap &&
            hostap_is_sta_assoc(local->ap, hdr->addr2)) {
                /* STA is actually associated with us even though it has a
                 * registered WDS link. Assume it is in 'AP client' mode.
                 * Since this is a 3-addr frame, assume it is not (bogus) WDS
                 * frame and process it like any normal ToDS frame from
                 * associated STA. */
                *wds = NULL;
        }

        return 0;
}


static int hostap_is_eapol_frame(local_info_t *local, struct sk_buff *skb)
{
        struct net_device *dev = local->dev;
        u16 fc, ethertype;
        struct ieee80211_hdr_4addr *hdr;
        u8 *pos;

        if (skb->len < 24)
                return 0;

        hdr = (struct ieee80211_hdr_4addr *) skb->data;
        fc = le16_to_cpu(hdr->frame_ctl);

        /* check that the frame is unicast frame to us */
        if ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
            IEEE80211_FCTL_TODS &&
            memcmp(hdr->addr1, dev->dev_addr, ETH_ALEN) == 0 &&
            memcmp(hdr->addr3, dev->dev_addr, ETH_ALEN) == 0) {
                /* ToDS frame with own addr BSSID and DA */
        } else if ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
                   IEEE80211_FCTL_FROMDS &&
                   memcmp(hdr->addr1, dev->dev_addr, ETH_ALEN) == 0) {
                /* FromDS frame with own addr as DA */
        } else
                return 0;

        if (skb->len < 24 + 8)
                return 0;

        /* check for port access entity Ethernet type */
        pos = skb->data + 24;
        ethertype = (pos[6] << 8) | pos[7];
        if (ethertype == ETH_P_PAE)
                return 1;

        return 0;
}


/* Called only as a tasklet (software IRQ) */
static int
hostap_rx_frame_decrypt(local_info_t *local, struct sk_buff *skb,
                        struct ieee80211_crypt_data *crypt)
{
        struct ieee80211_hdr_4addr *hdr;
        int res, hdrlen;

        if (crypt == NULL || crypt->ops->decrypt_mpdu == NULL)
                return 0;

        hdr = (struct ieee80211_hdr_4addr *) skb->data;
        hdrlen = hostap_80211_get_hdrlen(le16_to_cpu(hdr->frame_ctl));

        if (local->tkip_countermeasures &&
            strcmp(crypt->ops->name, "TKIP") == 0) {
                if (net_ratelimit()) {
                        printk(KERN_DEBUG "%s: TKIP countermeasures: dropped "
                               "received packet from " MAC_FMT "\n",
                               local->dev->name,
                               hdr->addr2[0], hdr->addr2[1], hdr->addr2[2],
                               hdr->addr2[3], hdr->addr2[4], hdr->addr2[5]);
                }
                return -1;
        }

        atomic_inc(&crypt->refcnt);
        res = crypt->ops->decrypt_mpdu(skb, hdrlen, crypt->priv);
        atomic_dec(&crypt->refcnt);
        if (res < 0) {
                printk(KERN_DEBUG "%s: decryption failed (SA=" MAC_FMT
                       ") res=%d\n",
                       local->dev->name,
                       hdr->addr2[0], hdr->addr2[1], hdr->addr2[2],
                       hdr->addr2[3], hdr->addr2[4], hdr->addr2[5],
                       res);
                local->comm_tallies.rx_discards_wep_undecryptable++;
                return -1;
        }

        return res;
}


/* Called only as a tasklet (software IRQ) */
static int
hostap_rx_frame_decrypt_msdu(local_info_t *local, struct sk_buff *skb,
                             int keyidx, struct ieee80211_crypt_data *crypt)
{
        struct ieee80211_hdr_4addr *hdr;
        int res, hdrlen;
        DECLARE_MAC_BUF(mac);

        if (crypt == NULL || crypt->ops->decrypt_msdu == NULL)
                return 0;

        hdr = (struct ieee80211_hdr_4addr *) skb->data;
        hdrlen = hostap_80211_get_hdrlen(le16_to_cpu(hdr->frame_ctl));

        atomic_inc(&crypt->refcnt);
        res = crypt->ops->decrypt_msdu(skb, keyidx, hdrlen, crypt->priv);
        atomic_dec(&crypt->refcnt);
        if (res < 0) {
                printk(KERN_DEBUG "%s: MSDU decryption/MIC verification failed"
                       " (SA=%s keyidx=%d)\n",
                       local->dev->name, print_mac(mac, hdr->addr2), keyidx);
                return -1;
        }

        return 0;
}


/* All received frames are sent to this function. @skb contains the frame in
 * IEEE 802.11 format, i.e., in the format it was sent over air.
 * This function is called only as a tasklet (software IRQ). */
void hostap_80211_rx(struct net_device *dev, struct sk_buff *skb,
                     struct hostap_80211_rx_status *rx_stats)
{
        struct hostap_interface *iface;
        local_info_t *local;
        struct ieee80211_hdr_4addr *hdr;
        size_t hdrlen;
        u16 fc, type, stype, sc;
        struct net_device *wds = NULL;
        struct net_device_stats *stats;
        unsigned int frag;
        u8 *payload;
        struct sk_buff *skb2 = NULL;
        u16 ethertype;
        int frame_authorized = 0;
        int from_assoc_ap = 0;
        u8 dst[ETH_ALEN];
        u8 src[ETH_ALEN];
        struct ieee80211_crypt_data *crypt = NULL;
        void *sta = NULL;
        int keyidx = 0;

        iface = netdev_priv(dev);
        local = iface->local;
        iface->stats.rx_packets++;
        iface->stats.rx_bytes += skb->len;

        /* dev is the master radio device; change this to be the default
         * virtual interface (this may be changed to WDS device below) */
        dev = local->ddev;
        iface = netdev_priv(dev);

        hdr = (struct ieee80211_hdr_4addr *) skb->data;
        stats = hostap_get_stats(dev);

        if (skb->len < 10)
                goto rx_dropped;

        fc = le16_to_cpu(hdr->frame_ctl);
        type = WLAN_FC_GET_TYPE(fc);
        stype = WLAN_FC_GET_STYPE(fc);
        sc = le16_to_cpu(hdr->seq_ctl);
        frag = WLAN_GET_SEQ_FRAG(sc);
        hdrlen = hostap_80211_get_hdrlen(fc);

        /* Put this code here so that we avoid duplicating it in all
         * Rx paths. - Jean II */
#ifdef IW_WIRELESS_SPY          /* defined in iw_handler.h */
        /* If spy monitoring on */
        if (iface->spy_data.spy_number > 0) {
                struct iw_quality wstats;
                wstats.level = rx_stats->signal;
                wstats.noise = rx_stats->noise;
                wstats.updated = IW_QUAL_LEVEL_UPDATED | IW_QUAL_NOISE_UPDATED
                        | IW_QUAL_QUAL_INVALID | IW_QUAL_DBM;
                /* Update spy records */
                wireless_spy_update(dev, hdr->addr2, &wstats);
        }
#endif /* IW_WIRELESS_SPY */
        hostap_update_rx_stats(local->ap, hdr, rx_stats);

        if (local->iw_mode == IW_MODE_MONITOR) {
                monitor_rx(dev, skb, rx_stats);
                return;
        }

        if (local->host_decrypt) {
                int idx = 0;
                if (skb->len >= hdrlen + 3)
                        idx = skb->data[hdrlen + 3] >> 6;
                crypt = local->crypt[idx];
                sta = NULL;

                /* Use station specific key to override default keys if the
                 * receiver address is a unicast address ("individual RA"). If
                 * bcrx_sta_key parameter is set, station specific key is used
                 * even with broad/multicast targets (this is against IEEE
                 * 802.11, but makes it easier to use different keys with
                 * stations that do not support WEP key mapping). */

                if (!(hdr->addr1[0] & 0x01) || local->bcrx_sta_key)
                        (void) hostap_handle_sta_crypto(local, hdr, &crypt,
                                                        &sta);

                /* allow NULL decrypt to indicate an station specific override
                 * for default encryption */
                if (crypt && (crypt->ops == NULL ||
                              crypt->ops->decrypt_mpdu == NULL))
                        crypt = NULL;

                if (!crypt && (fc & IEEE80211_FCTL_PROTECTED)) {
#if 0
                        /* This seems to be triggered by some (multicast?)
                         * frames from other than current BSS, so just drop the
                         * frames silently instead of filling system log with
                         * these reports. */
                        printk(KERN_DEBUG "%s: WEP decryption failed (not set)"
                               " (SA=" MAC_FMT ")\n",
                               local->dev->name,
                               hdr->addr2[0], hdr->addr2[1], hdr->addr2[2],
                               hdr->addr2[3], hdr->addr2[4], hdr->addr2[5]);
#endif
                        local->comm_tallies.rx_discards_wep_undecryptable++;
                        goto rx_dropped;
                }
        }

        if (type != IEEE80211_FTYPE_DATA) {
                if (type == IEEE80211_FTYPE_MGMT &&
                    stype == IEEE80211_STYPE_AUTH &&
                    fc & IEEE80211_FCTL_PROTECTED && local->host_decrypt &&
                    (keyidx = hostap_rx_frame_decrypt(local, skb, crypt)) < 0)
                {
                        printk(KERN_DEBUG "%s: failed to decrypt mgmt::auth "
                               "from " MAC_FMT "\n", dev->name,
                               hdr->addr2[0], hdr->addr2[1], hdr->addr2[2],
                               hdr->addr2[3], hdr->addr2[4], hdr->addr2[5]);
                        /* TODO: could inform hostapd about this so that it
                         * could send auth failure report */
                        goto rx_dropped;
                }

                if (hostap_rx_frame_mgmt(local, skb, rx_stats, type, stype))
                        goto rx_dropped;
                else
                        goto rx_exit;
        }

        /* Data frame - extract src/dst addresses */
        if (skb->len < IEEE80211_DATA_HDR3_LEN)
                goto rx_dropped;

        switch (fc & (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
        case IEEE80211_FCTL_FROMDS:
                memcpy(dst, hdr->addr1, ETH_ALEN);
                memcpy(src, hdr->addr3, ETH_ALEN);
                break;
        case IEEE80211_FCTL_TODS:
                memcpy(dst, hdr->addr3, ETH_ALEN);
                memcpy(src, hdr->addr2, ETH_ALEN);
                break;
        case IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS:
                if (skb->len < IEEE80211_DATA_HDR4_LEN)
                        goto rx_dropped;
                memcpy(dst, hdr->addr3, ETH_ALEN);
                memcpy(src, hdr->addr4, ETH_ALEN);
                break;
        case 0:
                memcpy(dst, hdr->addr1, ETH_ALEN);
                memcpy(src, hdr->addr2, ETH_ALEN);
                break;
        }

        if (hostap_rx_frame_wds(local, hdr, fc, &wds))
                goto rx_dropped;
        if (wds) {
                skb->dev = dev = wds;
                stats = hostap_get_stats(dev);
        }

        if (local->iw_mode == IW_MODE_MASTER && !wds &&
            (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
            IEEE80211_FCTL_FROMDS &&
            local->stadev &&
            memcmp(hdr->addr2, local->assoc_ap_addr, ETH_ALEN) == 0) {
                /* Frame from BSSID of the AP for which we are a client */
                skb->dev = dev = local->stadev;
                stats = hostap_get_stats(dev);
                from_assoc_ap = 1;
        }

        dev->last_rx = jiffies;

        if ((local->iw_mode == IW_MODE_MASTER ||
             local->iw_mode == IW_MODE_REPEAT) &&
            !from_assoc_ap) {
                switch (hostap_handle_sta_rx(local, dev, skb, rx_stats,
                                             wds != NULL)) {
                case AP_RX_CONTINUE_NOT_AUTHORIZED:
                        frame_authorized = 0;
                        break;
                case AP_RX_CONTINUE:
                        frame_authorized = 1;
                        break;
                case AP_RX_DROP:
                        goto rx_dropped;
                case AP_RX_EXIT:
                        goto rx_exit;
                }
        }

        /* Nullfunc frames may have PS-bit set, so they must be passed to
         * hostap_handle_sta_rx() before being dropped here. */
        if (stype != IEEE80211_STYPE_DATA &&
            stype != IEEE80211_STYPE_DATA_CFACK &&
            stype != IEEE80211_STYPE_DATA_CFPOLL &&
            stype != IEEE80211_STYPE_DATA_CFACKPOLL) {
                if (stype != IEEE80211_STYPE_NULLFUNC)
                        printk(KERN_DEBUG "%s: RX: dropped data frame "
                               "with no data (type=0x%02x, subtype=0x%02x)\n",
                               dev->name, type >> 2, stype >> 4);
                goto rx_dropped;
        }

        /* skb: hdr + (possibly fragmented, possibly encrypted) payload */

        if (local->host_decrypt && (fc & IEEE80211_FCTL_PROTECTED) &&
            (keyidx = hostap_rx_frame_decrypt(local, skb, crypt)) < 0)
                goto rx_dropped;
        hdr = (struct ieee80211_hdr_4addr *) skb->data;

        /* skb: hdr + (possibly fragmented) plaintext payload */

        if (local->host_decrypt && (fc & IEEE80211_FCTL_PROTECTED) &&
            (frag != 0 || (fc & IEEE80211_FCTL_MOREFRAGS))) {
                int flen;
                struct sk_buff *frag_skb =
                        prism2_frag_cache_get(local, hdr);
                if (!frag_skb) {
                        printk(KERN_DEBUG "%s: Rx cannot get skb from "
                               "fragment cache (morefrag=%d seq=%u frag=%u)\n",
                               dev->name, (fc & IEEE80211_FCTL_MOREFRAGS) != 0,
                               WLAN_GET_SEQ_SEQ(sc) >> 4, frag);
                        goto rx_dropped;
                }

                flen = skb->len;
                if (frag != 0)
                        flen -= hdrlen;

                if (frag_skb->tail + flen > frag_skb->end) {
                        printk(KERN_WARNING "%s: host decrypted and "
                               "reassembled frame did not fit skb\n",
                               dev->name);
                        prism2_frag_cache_invalidate(local, hdr);
                        goto rx_dropped;
                }

                if (frag == 0) {
                        /* copy first fragment (including full headers) into
                         * beginning of the fragment cache skb */
                        skb_copy_from_linear_data(skb, skb_put(frag_skb, flen),
                                                  flen);
                } else {
                        /* append frame payload to the end of the fragment
                         * cache skb */
                        skb_copy_from_linear_data_offset(skb, hdrlen,
                                                         skb_put(frag_skb,
                                                                 flen), flen);
                }
                dev_kfree_skb(skb);
                skb = NULL;

                if (fc & IEEE80211_FCTL_MOREFRAGS) {
                        /* more fragments expected - leave the skb in fragment
                         * cache for now; it will be delivered to upper layers
                         * after all fragments have been received */
                        goto rx_exit;
                }

                /* this was the last fragment and the frame will be
                 * delivered, so remove skb from fragment cache */
                skb = frag_skb;
                hdr = (struct ieee80211_hdr_4addr *) skb->data;
                prism2_frag_cache_invalidate(local, hdr);
        }

        /* skb: hdr + (possible reassembled) full MSDU payload; possibly still
         * encrypted/authenticated */

        if (local->host_decrypt && (fc & IEEE80211_FCTL_PROTECTED) &&
            hostap_rx_frame_decrypt_msdu(local, skb, keyidx, crypt))
                goto rx_dropped;

        hdr = (struct ieee80211_hdr_4addr *) skb->data;
        if (crypt && !(fc & IEEE80211_FCTL_PROTECTED) && !local->open_wep) {
                if (local->ieee_802_1x &&
                    hostap_is_eapol_frame(local, skb)) {
                        /* pass unencrypted EAPOL frames even if encryption is
                         * configured */
                        PDEBUG(DEBUG_EXTRA2, "%s: RX: IEEE 802.1X - passing "
                               "unencrypted EAPOL frame\n", local->dev->name);
                } else {
                        printk(KERN_DEBUG "%s: encryption configured, but RX "
                               "frame not encrypted (SA=" MAC_FMT ")\n",
                               local->dev->name,
                               hdr->addr2[0], hdr->addr2[1], hdr->addr2[2],
                               hdr->addr2[3], hdr->addr2[4], hdr->addr2[5]);
                        goto rx_dropped;
                }
        }

        if (local->drop_unencrypted && !(fc & IEEE80211_FCTL_PROTECTED) &&
            !hostap_is_eapol_frame(local, skb)) {

                if (net_ratelimit()) {
                        printk(KERN_DEBUG "%s: dropped unencrypted RX data "
                               "frame from " MAC_FMT " (drop_unencrypted=1)\n",
                               dev->name,
                               hdr->addr2[0], hdr->addr2[1], hdr->addr2[2],
                               hdr->addr2[3], hdr->addr2[4], hdr->addr2[5]);
                }
                goto rx_dropped;
        }

        /* skb: hdr + (possible reassembled) full plaintext payload */

        payload = skb->data + hdrlen;
        ethertype = (payload[6] << 8) | payload[7];

        /* If IEEE 802.1X is used, check whether the port is authorized to send
         * the received frame. */
        if (local->ieee_802_1x && local->iw_mode == IW_MODE_MASTER) {
                if (ethertype == ETH_P_PAE) {
                        PDEBUG(DEBUG_EXTRA2, "%s: RX: IEEE 802.1X frame\n",
                               dev->name);
                        if (local->hostapd && local->apdev) {
                                /* Send IEEE 802.1X frames to the user
                                 * space daemon for processing */
                                prism2_rx_80211(local->apdev, skb, rx_stats,
                                                PRISM2_RX_MGMT);
                                local->apdevstats.rx_packets++;
                                local->apdevstats.rx_bytes += skb->len;
                                goto rx_exit;
                        }
                } else if (!frame_authorized) {
                        printk(KERN_DEBUG "%s: dropped frame from "
                               "unauthorized port (IEEE 802.1X): "
                               "ethertype=0x%04x\n",
                               dev->name, ethertype);
                        goto rx_dropped;
                }
        }

        /* convert hdr + possible LLC headers into Ethernet header */
        if (skb->len - hdrlen >= 8 &&
            ((memcmp(payload, rfc1042_header, 6) == 0 &&
              ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
             memcmp(payload, bridge_tunnel_header, 6) == 0)) {
                /* remove RFC1042 or Bridge-Tunnel encapsulation and
                 * replace EtherType */
                skb_pull(skb, hdrlen + 6);
                memcpy(skb_push(skb, ETH_ALEN), src, ETH_ALEN);
                memcpy(skb_push(skb, ETH_ALEN), dst, ETH_ALEN);
        } else {
                __be16 len;
                /* Leave Ethernet header part of hdr and full payload */
                skb_pull(skb, hdrlen);
                len = htons(skb->len);
                memcpy(skb_push(skb, 2), &len, 2);
                memcpy(skb_push(skb, ETH_ALEN), src, ETH_ALEN);
                memcpy(skb_push(skb, ETH_ALEN), dst, ETH_ALEN);
        }

        if (wds && ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
                    IEEE80211_FCTL_TODS) &&
            skb->len >= ETH_HLEN + ETH_ALEN) {
                /* Non-standard frame: get addr4 from its bogus location after
                 * the payload */
                skb_copy_from_linear_data_offset(skb, skb->len - ETH_ALEN,
                                                 skb->data + ETH_ALEN,
                                                 ETH_ALEN);
                skb_trim(skb, skb->len - ETH_ALEN);
        }

        stats->rx_packets++;
        stats->rx_bytes += skb->len;

        if (local->iw_mode == IW_MODE_MASTER && !wds &&
            local->ap->bridge_packets) {
                if (dst[0] & 0x01) {
                        /* copy multicast frame both to the higher layers and
                         * to the wireless media */
                        local->ap->bridged_multicast++;
                        skb2 = skb_clone(skb, GFP_ATOMIC);
                        if (skb2 == NULL)
                                printk(KERN_DEBUG "%s: skb_clone failed for "
                                       "multicast frame\n", dev->name);
                } else if (hostap_is_sta_authorized(local->ap, dst)) {
                        /* send frame directly to the associated STA using
                         * wireless media and not passing to higher layers */
                        local->ap->bridged_unicast++;
                        skb2 = skb;
                        skb = NULL;
                }
        }

        if (skb2 != NULL) {
                /* send to wireless media */
                skb2->dev = dev;
                skb2->protocol = __constant_htons(ETH_P_802_3);
                skb_reset_mac_header(skb2);
                skb_reset_network_header(skb2);
                /* skb2->network_header += ETH_HLEN; */
                dev_queue_xmit(skb2);
        }

        if (skb) {
                skb->protocol = eth_type_trans(skb, dev);
                memset(skb->cb, 0, sizeof(skb->cb));
                netif_rx(skb);
        }

 rx_exit:
        if (sta)
                hostap_handle_sta_release(sta);
        return;

 rx_dropped:
        dev_kfree_skb(skb);

        stats->rx_dropped++;
        goto rx_exit;
}


EXPORT_SYMBOL(hostap_80211_rx);