hostap_80211_rx.c

IEEE 802.11a/b/g linux2.4/2.6 驱动程序源代码

	/* 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 */
#endif /* WIRELESS_EXT > 15 */
	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 & WLAN_FC_ISWEP)) {
#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=" MACSTR ")\n",
			       local->dev->name, MAC2STR(hdr->addr2));
#endif
			local->comm_tallies.rx_discards_wep_undecryptable++;
			goto rx_dropped;
		}
	}

	if (type != WLAN_FC_TYPE_DATA) {
		if (type == WLAN_FC_TYPE_MGMT && stype == WLAN_FC_STYPE_AUTH &&
		    fc & WLAN_FC_ISWEP && local->host_decrypt &&
		    (keyidx = hostap_rx_frame_decrypt(local, skb, crypt)) < 0)
		{
			printk(KERN_DEBUG "%s: failed to decrypt mgmt::auth "
			       "from " MACSTR "\n", dev->name,
			       MAC2STR(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 & (WLAN_FC_FROMDS | WLAN_FC_TODS)) {
	case WLAN_FC_FROMDS:
		memcpy(dst, hdr->addr1, ETH_ALEN);
		memcpy(src, hdr->addr3, ETH_ALEN);
		break;
	case WLAN_FC_TODS:
		memcpy(dst, hdr->addr3, ETH_ALEN);
		memcpy(src, hdr->addr2, ETH_ALEN);
		break;
	case WLAN_FC_FROMDS | WLAN_FC_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 & (WLAN_FC_TODS | WLAN_FC_FROMDS)) == WLAN_FC_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 != WLAN_FC_STYPE_DATA &&
	    stype != WLAN_FC_STYPE_DATA_CFACK &&
	    stype != WLAN_FC_STYPE_DATA_CFPOLL &&
	    stype != WLAN_FC_STYPE_DATA_CFACKPOLL) {
		if (stype != WLAN_FC_STYPE_NULLFUNC)
			printk(KERN_DEBUG "%s: RX: dropped data frame "
			       "with no data (type=0x%02x, subtype=0x%02x)\n",
			       dev->name, type, stype);
		goto rx_dropped;
	}

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

	if (local->host_decrypt && (fc & WLAN_FC_ISWEP) &&
	    (keyidx = hostap_rx_frame_decrypt(local, skb, crypt)) < 0)
		goto rx_dropped;
	hdr = (struct hostap_ieee80211_hdr *) skb->data;

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

	if (local->host_decrypt && (fc & WLAN_FC_ISWEP) &&
	    (frag != 0 || (fc & WLAN_FC_MOREFRAG))) {
		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 & WLAN_FC_MOREFRAG) != 0,
			       WLAN_GET_SEQ_SEQ(sc), 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 */
			memcpy(skb_put(frag_skb, flen), skb->data, flen);
		} else {
			/* append frame payload to the end of the fragment
			 * cache skb */
			memcpy(skb_put(frag_skb, flen), skb->data + hdrlen,
			       flen);
		}
		dev_kfree_skb(skb);
		skb = NULL;

		if (fc & WLAN_FC_MOREFRAG) {
			/* 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 hostap_ieee80211_hdr *) skb->data;
		prism2_frag_cache_invalidate(local, hdr);
	}

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

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

	hdr = (struct hostap_ieee80211_hdr *) skb->data;
	if (crypt && !(fc & WLAN_FC_ISWEP) && !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=" MACSTR ")\n",
			       local->dev->name, MAC2STR(hdr->addr2));
			goto rx_dropped;
		}
	}

	if (local->drop_unencrypted && !(fc & WLAN_FC_ISWEP) &&
	    !hostap_is_eapol_frame(local, skb)) {
		if (net_ratelimit()) {
			printk(KERN_DEBUG "%s: dropped unencrypted RX data "
			       "frame from " MACSTR " (drop_unencrypted=1)\n",
			       dev->name, MAC2STR(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 & (WLAN_FC_TODS | WLAN_FC_FROMDS)) == WLAN_FC_TODS) &&
	    skb->len >= ETH_HLEN + ETH_ALEN) {
		/* Non-standard frame: get addr4 from its bogus location after
		 * the payload */
		memcpy(skb->data + ETH_ALEN,
		       skb->data + skb->len - 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->protocol = __constant_htons(ETH_P_802_3);
		skb2->mac.raw = skb2->nh.raw = skb2->data;
		/* skb2->nh.raw = skb2->data + ETH_HLEN; */
		skb2->dev = dev;
		dev_queue_xmit(skb2);
	}

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