ieee80211_rx.c

Source for the 802.11 (wireless) network stack for Linux

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

	dev->last_rx = jiffies;

#ifdef NOT_YET
	if ((ieee->iw_mode == IW_MODE_MASTER ||
	     ieee->iw_mode == IW_MODE_REPEAT) && !from_assoc_ap) {
		switch (hostap_handle_sta_rx(ieee, 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;
		}
	}
#endif

	/* Nullfunc frames may have PS-bit set, so they must be passed to
	 * hostap_handle_sta_rx() before being dropped here. */

	stype &= ~IEEE80211_STYPE_QOS_DATA;

	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)
			IEEE80211_DEBUG_DROP("RX: dropped data frame "
					     "with no data (type=0x%02x, "
					     "subtype=0x%02x, len=%d)\n",
					     type, stype, skb->len);
		goto rx_dropped;
	}

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

	if (ieee->host_decrypt && (fc & IEEE80211_FCTL_PROTECTED) &&
	    (keyidx = ieee80211_rx_frame_decrypt(ieee, skb, crypt)) < 0)
		goto rx_dropped;

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

	/* skb: hdr + (possibly fragmented) plaintext payload */
	// PR: FIXME: hostap has additional conditions in the "if" below:
	// ieee->host_decrypt && (fc & IEEE80211_FCTL_PROTECTED) &&
	if ((frag != 0 || (fc & IEEE80211_FCTL_MOREFRAGS))) {
		int flen;
		struct sk_buff *frag_skb = ieee80211_frag_cache_get(ieee, hdr);
		IEEE80211_DEBUG_FRAG("Rx Fragment received (%u)\n", frag);

		if (!frag_skb) {
			IEEE80211_DEBUG(IEEE80211_DL_RX | IEEE80211_DL_FRAG,
					"Rx cannot get skb from fragment "
					"cache (morefrag=%d seq=%u frag=%u)\n",
					(fc & IEEE80211_FCTL_MOREFRAGS) != 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);
			ieee80211_frag_cache_invalidate(ieee, 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_any(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;
		ieee80211_frag_cache_invalidate(ieee, hdr);
	}

	/* skb: hdr + (possible reassembled) full MSDU payload; possibly still
	 * encrypted/authenticated */
	if (ieee->host_decrypt && (fc & IEEE80211_FCTL_PROTECTED) &&
	    ieee80211_rx_frame_decrypt_msdu(ieee, skb, keyidx, crypt))
		goto rx_dropped;

	hdr = (struct ieee80211_hdr_4addr *)skb->data;
	if (crypt && !(fc & IEEE80211_FCTL_PROTECTED) && !ieee->open_wep) {
		if (		/*ieee->ieee802_1x && */
			   ieee80211_is_eapol_frame(ieee, skb)) {
			/* pass unencrypted EAPOL frames even if encryption is
			 * configured */
		} else {
			IEEE80211_DEBUG_DROP("encryption configured, but RX "
					     "frame not encrypted (SA=" MAC_FMT
					     ")\n", MAC_ARG(hdr->addr2));
			goto rx_dropped;
		}
	}

	if (crypt && !(fc & IEEE80211_FCTL_PROTECTED) && !ieee->open_wep &&
	    !ieee80211_is_eapol_frame(ieee, skb)) {
		IEEE80211_DEBUG_DROP("dropped unencrypted RX data "
				     "frame from " MAC_FMT
				     " (drop_unencrypted=1)\n",
				     MAC_ARG(hdr->addr2));
		goto rx_dropped;
	}

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

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

#ifdef NOT_YET
	/* If IEEE 802.1X is used, check whether the port is authorized to send
	 * the received frame. */
	if (ieee->ieee802_1x && ieee->iw_mode == IW_MODE_MASTER) {
		if (ethertype == ETH_P_PAE) {
			printk(KERN_DEBUG "%s: RX: IEEE 802.1X frame\n",
			       dev->name);
			if (ieee->hostapd && ieee->apdev) {
				/* Send IEEE 802.1X frames to the user
				 * space daemon for processing */
				prism2_rx_80211(ieee->apdev, skb, rx_stats,
						PRISM2_RX_MGMT);
				ieee->apdevstats.rx_packets++;
				ieee->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;
		}
	}
#endif

	/* convert hdr + possible LLC headers into Ethernet header */
	if (skb->len - hdrlen >= 8 &&
	    ((memcmp(payload, rfc1042_header, SNAP_SIZE) == 0 &&
	      ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
	     memcmp(payload, bridge_tunnel_header, SNAP_SIZE) == 0)) {
		/* remove RFC1042 or Bridge-Tunnel encapsulation and
		 * replace EtherType */
		skb_pull(skb, hdrlen + SNAP_SIZE);
		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);
	}

#ifdef NOT_YET
	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 */
		memcpy(skb->data + ETH_ALEN,
		       skb->data + skb->len - ETH_ALEN, ETH_ALEN);
		skb_trim(skb, skb->len - ETH_ALEN);
	}
#endif

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

#ifdef NOT_YET
	if (ieee->iw_mode == IW_MODE_MASTER && !wds && ieee->ap->bridge_packets) {
		if (dst[0] & 0x01) {
			/* copy multicast frame both to the higher layers and
			 * to the wireless media */
			ieee->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_assoc(ieee->ap, dst)) {
			/* send frame directly to the associated STA using
			 * wireless media and not passing to higher layers */
			ieee->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);
	}
#endif

	if (skb) {
		skb->protocol = eth_type_trans(skb, dev);
		memset(skb->cb, 0, sizeof(skb->cb));
		skb->dev = dev;
		skb->ip_summed = CHECKSUM_NONE;	/* 802.11 crc not sufficient */
		netif_rx(skb);
	}

      rx_exit:
#ifdef NOT_YET
	if (sta)
		hostap_handle_sta_release(sta);
#endif
	return 1;

      rx_dropped:
	stats->rx_dropped++;

	/* Returning 0 indicates to caller that we have not handled the SKB--
	 * so it is still allocated and can be used again by underlying
	 * hardware as a DMA target */
	return 0;
}

#define MGMT_FRAME_FIXED_PART_LENGTH		0x24

static u8 qos_oui[QOS_OUI_LEN] = { 0x00, 0x50, 0xF2 };

/*
* Make ther structure we read from the beacon packet has
* the right values
*/
static int ieee80211_verify_qos_info(struct ieee80211_qos_information_element
				     *info_element, int sub_type)
{

	if (info_element->qui_subtype != sub_type)
		return -1;
	if (memcmp(info_element->qui, qos_oui, QOS_OUI_LEN))
		return -1;
	if (info_element->qui_type != QOS_OUI_TYPE)
		return -1;
	if (info_element->version != QOS_VERSION_1)
		return -1;

	return 0;
}

/*
 * Parse a QoS parameter element
 */
static int ieee80211_read_qos_param_element(struct ieee80211_qos_parameter_info
					    *element_param, struct ieee80211_info_element
					    *info_element)
{
	int ret = 0;
	u16 size = sizeof(struct ieee80211_qos_parameter_info) - 2;

	if ((info_element == NULL) || (element_param == NULL))
		return -1;

	if (info_element->id == QOS_ELEMENT_ID && info_element->len == size) {
		memcpy(element_param->info_element.qui, info_element->data,
		       info_element->len);
		element_param->info_element.elementID = info_element->id;
		element_param->info_element.length = info_element->len;
	} else
		ret = -1;
	if (ret == 0)
		ret = ieee80211_verify_qos_info(&element_param->info_element,
						QOS_OUI_PARAM_SUB_TYPE);
	return ret;
}

/*
 * Parse a QoS information element
 */
static int ieee80211_read_qos_info_element(struct
					   ieee80211_qos_information_element
					   *element_info, struct ieee80211_info_element
					   *info_element)
{
	int ret = 0;
	u16 size = sizeof(struct ieee80211_qos_information_element) - 2;

	if (element_info == NULL)
		return -1;
	if (info_element == NULL)
		return -1;

	if ((info_element->id == QOS_ELEMENT_ID) && (info_element->len == size)) {
		memcpy(element_info->qui, info_element->data,
		       info_element->len);
		element_info->elementID = info_element->id;
		element_info->length = info_element->len;
	} else
		ret = -1;

	if (ret == 0)
		ret = ieee80211_verify_qos_info(element_info,
						QOS_OUI_INFO_SUB_TYPE);
	return ret;
}

/*
 * Write QoS parameters from the ac parameters.
 */
static int ieee80211_qos_convert_ac_to_parameters(struct
						  ieee80211_qos_parameter_info
						  *param_elm, struct
						  ieee80211_qos_parameters
						  *qos_param)
{
	int rc = 0;
	int i;
	struct ieee80211_qos_ac_parameter *ac_params;
	u32 txop;
	u8 cw_min;
	u8 cw_max;

	for (i = 0; i < QOS_QUEUE_NUM; i++) {
		ac_params = &(param_elm->ac_params_record[i]);

		qos_param->aifs[i] = (ac_params->aci_aifsn) & 0x0F;
		qos_param->aifs[i] -= (qos_param->aifs[i] < 2) ? 0 : 2;

		cw_min = ac_params->ecw_min_max & 0x0F;
		qos_param->cw_min[i] = (u16) ((1 << cw_min) - 1);

		cw_max = (ac_params->ecw_min_max & 0xF0) >> 4;
		qos_param->cw_max[i] = (u16) ((1 << cw_max) - 1);

		qos_param->flag[i] =
		    (ac_params->aci_aifsn & 0x10) ? 0x01 : 0x00;

		txop = le16_to_cpu(ac_params->tx_op_limit) * 32;
		qos_param->tx_op_limit[i] = (u16) txop;
	}
	return rc;
}

/*
 * we have a generic data element which it may contain QoS information or
 * parameters element. check the information element length to decide
 * which type to read
 */
static int ieee80211_parse_qos_info_param_IE(struct ieee80211_info_element
					     *info_element,
					     struct ieee80211_network *network)
{
	int rc = 0;
	struct ieee80211_qos_parameters *qos_param = NULL;
	struct ieee80211_qos_information_element qos_info_element;

	rc = ieee80211_read_qos_info_element(&qos_info_element, info_element);

	if (rc == 0) {
		network->qos_data.param_count = qos_info_element.ac_info & 0x0F;
		network->flags |= NETWORK_HAS_QOS_INFORMATION;
	} else {
		struct ieee80211_qos_parameter_info param_element;

		rc = ieee80211_read_qos_param_element(&param_element,
						      info_element);
		if (rc == 0) {
			qos_param = &(network->qos_data.parameters);
			ieee80211_qos_convert_ac_to_parameters(&param_element,
							       qos_param);
			network->flags |= NETWORK_HAS_QOS_PARAMETERS;
			network->qos_data.param_count =
			    param_element.info_element.ac_info & 0x0F;
		}
	}

	if (rc == 0) {
		IEEE80211_DEBUG_QOS("QoS is supported\n");
		network->qos_data.supported = 1;
	}
	return rc;
}

static int ieee80211_parse_info_param(struct ieee80211_info_element
				      *info_element, u16 length,
				      struct ieee80211_network *network)
{
	u8 i;
#ifdef CONFIG_IEEE80211_DEBUG
	char rates_str[64];
	char *p;
#endif

	while (length >= sizeof(*info_element)) {
		if (sizeof(*info_element) + info_element->len > length) {
			IEEE80211_DEBUG_MGMT("Info elem: parse failed: "
					     "info_element->len + 2 > left : "
					     "info_element->len+2=%zd left=%d, id=%d.\n",
					     info_element->len +
					     sizeof(*info_element),
					     length, info_element->id);
			return 1;
		}

		switch (info_element->id) {
		case MFIE_TYPE_SSID:
			if (ieee80211_is_empty_essid(info_element->data,
						     info_element->len)) {
				network->flags |= NETWORK_EMPTY_ESSID;
				break;
			}

			network->ssid_len = min(info_element->len,
						(u8) IW_ESSID_MAX_SIZE);
			memcpy(network->ssid, info_element->data,
			       network->ssid_len);
			if (network->ssid_len < IW_ESSID_MAX_SIZE)
				memset(network->ssid + network->ssid_len, 0,
				       IW_ESSID_MAX_SIZE - network->ssid_len);

			IEEE80211_DEBUG_MGMT("MFIE_TYPE_SSID: '%s' len=%d.\n",
					     network->ssid, network->ssid_len);
			break;

		case MFIE_TYPE_RATES:
#ifdef CONFIG_IEEE80211_DEBUG
			p = rates_str;
#endif
			network->rates_len = min(info_element->len,
						 MAX_RATES_LENGTH);
			for (i = 0; i < network->rates_len; i++) {
				network->rates[i] = info_element->data[i];
#ifdef CONFIG_IEEE80211_DEBUG
				p += snprintf(p, sizeof(rates_str) -
					      (p - rates_str), "%02X ",
					      network->rates[i]);
#endif
				if (ieee80211_is_ofdm_rate
				    (info_element->data[i])) {
					network->flags |= NETWORK_HAS_OFDM;
					if (info_element->data[i] &
					    IEEE80211_BASIC_RATE_MASK)
						network->flags &=
						    ~NETWORK_HAS_CCK;
				}
			}

			IEEE80211_DEBUG_MGMT("MFIE_TYPE_RATES: '%s' (%d)\n",
					     rates_str, network->rates_len);
			break;

		case MFIE_TYPE_RATES_EX:
#ifdef CONFIG_IEEE80211_DEBUG
			p = rates_str;
#endif
			network->rates_ex_len = min(info_element->len,
						    MAX_RATES_EX_LENGTH);
			for (i = 0; i < network->rates_ex_len; i++) {
				network->rates_ex[i] = info_element->data[i];
#ifdef CONFIG_IEEE80211_DEBUG
				p += snprintf(p, sizeof(rates_str) -
					      (p - rates_str), "%02X ",
					      network->rates[i]);
#endif
				if (ieee80211_is_ofdm_rate
				    (info_element->data[i])) {
					network->flags |= NETWORK_HAS_OFDM;
					if (info_element->data[i] &
					    IEEE80211_BASIC_RATE_MASK)
						network->flags &=
						    ~NETWORK_HAS_CCK;