Logo Search packages:      
Sourcecode: linux version File versions  Download package

hostap_80211_rx.c

#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;
      DECLARE_MAC_BUF(mac);

      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 %s\n",
                         local->dev->name, print_mac(mac, hdr->addr2));
            }
            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=%s"
                   ") res=%d\n",
                   local->dev->name, print_mac(mac, hdr->addr2), 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;
      DECLARE_MAC_BUF(mac);

      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=%s)\n",
                         local->dev->name, print_mac(mac, hdr->addr2));
#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 %s\n", dev->name,
                         print_mac(mac, hdr->addr2));
                  /* 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=%s)\n",
                         local->dev->name, print_mac(mac, hdr->addr2));
                  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 %s"
                         " (drop_unencrypted=1)\n",
                         dev->name, print_mac(mac, hdr->addr2));
            }
            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 {
            u16 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);

Generated by  Doxygen 1.6.0   Back to index