hostap_80211_rx.c

IEEE 802.11a/b/g linux2.4/2.6 驱动程序源代码

#include <linux/etherdevice.h>

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

void hostap_dump_rx_80211(const char *name, struct sk_buff *skb,
			  struct hostap_80211_rx_status *rx_stats)
{
	struct hostap_ieee80211_hdr *hdr;
	u16 fc;

	hdr = (struct hostap_ieee80211_hdr *) 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_control);
	printk(KERN_DEBUG "   FC=0x%04x (type=%d:%d)%s%s",
	       fc, WLAN_FC_GET_TYPE(fc), WLAN_FC_GET_STYPE(fc),
	       fc & WLAN_FC_TODS ? " [ToDS]" : "",
	       fc & WLAN_FC_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_ctrl));

	printk(KERN_DEBUG "   A1=" MACSTR " A2=" MACSTR " A3=" MACSTR,
	       MAC2STR(hdr->addr1), MAC2STR(hdr->addr2), MAC2STR(hdr->addr3));
	if (skb->len >= 30)
		printk(" A4=" MACSTR, MAC2STR(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 = dev->priv;
	local_info_t *local = iface->local;
	int hdrlen, phdrlen, head_need, tail_need;
	u16 fc;
	int prism_header, ret;
	struct hostap_ieee80211_hdr *hdr;

	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 hostap_ieee80211_hdr *) skb->data;
	fc = le16_to_cpu(hdr->frame_control);

	if (type == PRISM2_RX_MGMT && (fc & WLAN_FC_PVER)) {
		printk(KERN_DEBUG "%s: dropped management frame with header "
		       "version %d\n", dev->name, fc & WLAN_FC_PVER);
		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->mac.raw = skb->data;
	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 hostap_ieee80211_hdr *hdr)
{
	struct sk_buff *skb = NULL;
	u16 sc;
	unsigned int frag, seq;
	struct prism2_frag_entry *entry;

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

	if (frag == 0) {
		/* Reserve enough space to fit maximum frame length */
		skb = dev_alloc_skb(local->dev->mtu +
				    sizeof(struct hostap_ieee80211_hdr) +
				    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 hostap_ieee80211_hdr *hdr)
{
	u16 sc;
	unsigned int seq;
	struct prism2_frag_entry *entry;

	sc = le16_to_cpu(hdr->seq_ctrl);
	seq = WLAN_GET_SEQ_SEQ(sc);

	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;