path: root/net/mac80211/scan.c

/*
 * Scanning implementation
 *
 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
 * Copyright 2004, Instant802 Networks, Inc.
 * Copyright 2005, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/* TODO:
 * order BSS list by RSSI(?) ("quality of AP")
 * scan result table filtering (by capability (privacy, IBSS/BSS, WPA/RSN IE,
 *    SSID)
 */

#include <linux/wireless.h>
#include <linux/if_arp.h>
#include <net/mac80211.h>
#include <net/iw_handler.h>

#include "ieee80211_i.h"
#include "mesh.h"

#define IEEE80211_PROBE_DELAY (HZ / 33)
#define IEEE80211_CHANNEL_TIME (HZ / 33)
#define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 5)

void ieee80211_rx_bss_list_init(struct ieee80211_local *local)
{
	spin_lock_init(&local->bss_lock);
	INIT_LIST_HEAD(&local->bss_list);
}

void ieee80211_rx_bss_list_deinit(struct ieee80211_local *local)
{
	struct ieee80211_bss *bss, *tmp;

	list_for_each_entry_safe(bss, tmp, &local->bss_list, list)
		ieee80211_rx_bss_put(local, bss);
}

struct ieee80211_bss *
ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
		     u8 *ssid, u8 ssid_len)
{
	struct ieee80211_bss *bss;

	spin_lock_bh(&local->bss_lock);
	bss = local->bss_hash[STA_HASH(bssid)];
	while (bss) {
		if (!bss_mesh_cfg(bss) &&
		    !memcmp(bss->bssid, bssid, ETH_ALEN) &&
		    bss->freq == freq &&
		    bss->ssid_len == ssid_len &&
		    (ssid_len == 0 || !memcmp(bss->ssid, ssid, ssid_len))) {
			atomic_inc(&bss->users);
			break;
		}
		bss = bss->hnext;
	}
	spin_unlock_bh(&local->bss_lock);
	return bss;
}

/* Caller must hold local->bss_lock */
static void __ieee80211_rx_bss_hash_add(struct ieee80211_local *local,
					struct ieee80211_bss *bss)
{
	u8 hash_idx;

	if (bss_mesh_cfg(bss))
		hash_idx = mesh_id_hash(bss_mesh_id(bss),
					bss_mesh_id_len(bss));
	else
		hash_idx = STA_HASH(bss->bssid);

	bss->hnext = local->bss_hash[hash_idx];
	local->bss_hash[hash_idx] = bss;
}

/* Caller must hold local->bss_lock */
static void __ieee80211_rx_bss_hash_del(struct ieee80211_local *local,
					struct ieee80211_bss *bss)
{
	struct ieee80211_bss *b, *prev = NULL;
	b = local->bss_hash[STA_HASH(bss->bssid)];
	while (b) {
		if (b == bss) {
			if (!prev)
				local->bss_hash[STA_HASH(bss->bssid)] =
					bss->hnext;
			else
				prev->hnext = bss->hnext;
			break;
		}
		prev = b;
		b = b->hnext;
	}
}

struct ieee80211_bss *
ieee80211_rx_bss_add(struct ieee80211_local *local, u8 *bssid, int freq,
		     u8 *ssid, u8 ssid_len)
{
	struct ieee80211_bss *bss;

	bss = kzalloc(sizeof(*bss), GFP_ATOMIC);
	if (!bss)
		return NULL;
	atomic_set(&bss->users, 2);
	memcpy(bss->bssid, bssid, ETH_ALEN);
	bss->freq = freq;
	if (ssid && ssid_len <= IEEE80211_MAX_SSID_LEN) {
		memcpy(bss->ssid, ssid, ssid_len);
		bss->ssid_len = ssid_len;
	}

	spin_lock_bh(&local->bss_lock);
	/* TODO: order by RSSI? */
	list_add_tail(&bss->list, &local->bss_list);
	__ieee80211_rx_bss_hash_add(local, bss);
	spin_unlock_bh(&local->bss_lock);
	return bss;
}

#ifdef CONFIG_MAC80211_MESH
static struct ieee80211_bss *
ieee80211_rx_mesh_bss_get(struct ieee80211_local *local, u8 *mesh_id, int mesh_id_len,
			  u8 *mesh_cfg, int freq)
{
	struct ieee80211_bss *bss;

	spin_lock_bh(&local->bss_lock);
	bss = local->bss_hash[mesh_id_hash(mesh_id, mesh_id_len)];
	while (bss) {
		if (bss_mesh_cfg(bss) &&
		    !memcmp(bss_mesh_cfg(bss), mesh_cfg, MESH_CFG_CMP_LEN) &&
		    bss->freq == freq &&
		    mesh_id_len == bss->mesh_id_len &&
		    (mesh_id_len == 0 || !memcmp(bss->mesh_id, mesh_id,
						 mesh_id_len))) {
			atomic_inc(&bss->users);
			break;
		}
		bss = bss->hnext;
	}
	spin_unlock_bh(&local->bss_lock);
	return bss;
}

static struct ieee80211_bss *
ieee80211_rx_mesh_bss_add(struct ieee80211_local<