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madwifi: improve the autochannel decision making on systems with multiple cards

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git-svn-id: svn://svn.openwrt.org/openwrt/trunk@14748 3c298f89-4303-0410-b956-a3cf2f4a3e73
This commit is contained in:
nbd 2009-03-04 21:39:46 +00:00
parent 1d3e394ebe
commit 8c3be08d37
1 changed files with 347 additions and 0 deletions
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347
package/madwifi/patches/460-autochannel_multi.patch Normal file
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@ -0,0 +1,347 @@
--- a/net80211/ieee80211_scan.c
+++ b/net80211/ieee80211_scan.c
@@ -97,6 +97,123 @@ struct scan_state {
static void scan_restart_pwrsav(unsigned long);
static void scan_next(unsigned long);
+spinlock_t channel_lock = SPIN_LOCK_UNLOCKED;
+static LIST_HEAD(channels_inuse);
+
+struct channel_inuse {
+ struct list_head list;
+ struct ieee80211com *ic;
+ u16 freq;
+ u8 bw;
+};
+
+static inline u32
+get_signal(u8 bw, u8 distance)
+{
+ u32 v;
+
+ /* signal = 1 - (distance / bw)^2 [scale: 100] */
+ v = 100 * distance / bw;
+ v = (100 - ((v * v) / 100));
+ return v;
+}
+
+static u32
+get_overlap(u16 f1, u16 f2, u8 b1, u8 b2)
+{
+ u32 v;
+ u16 d, c;
+
+ /* add offsets for sidechannel interference */
+ b1 += (b1 / 5);
+ b2 += (b2 / 5);
+
+ /* use only one direction */
+ b1 /= 2;
+ b2 /= 2;
+
+ if (f1 + b1 < f2 - b2)
+ return 0;
+
+ d = f2 - f1;
+ c = d * b1 / (b1 + b2);
+ v = get_signal(b1, c);
+
+ return v * v / 100;
+}
+
+static u8
+get_channel_bw(struct ieee80211_channel *c)
+{
+ switch(c->ic_flags & (
+ IEEE80211_CHAN_HALF |
+ IEEE80211_CHAN_QUARTER |
+ IEEE80211_CHAN_TURBO |
+ IEEE80211_CHAN_STURBO)) {
+ case IEEE80211_CHAN_QUARTER:
+ return 5;
+ case IEEE80211_CHAN_HALF:
+ return 10;
+ case IEEE80211_CHAN_TURBO:
+ case IEEE80211_CHAN_STURBO:
+ return 40;
+ default:
+ return 20;
+ }
+}
+
+/* must be called with channel_lock held */
+u32
+ieee80211_scan_get_bias(struct ieee80211_channel *c)
+{
+ struct channel_inuse *ch;
+ u8 bw = get_channel_bw(c);
+ u32 bias = 0;
+
+ list_for_each_entry(ch, &channels_inuse, list) {
+ if (ch->freq == c->ic_freq) {
+ bias += 50;
+ continue;
+ }
+ if (c->ic_freq < ch->freq)
+ bias += get_overlap(c->ic_freq, ch->freq, bw, ch->bw);
+ else
+ bias += get_overlap(ch->freq, c->ic_freq, ch->bw, bw);
+ }
+ return min(bias, (u32) 100);
+}
+EXPORT_SYMBOL(ieee80211_scan_get_bias);
+
+/* must be called with channel_lock held */
+void
+ieee80211_scan_set_bss_channel(struct ieee80211com *ic, struct ieee80211_channel *c)
+{
+ unsigned long flags;
+ struct channel_inuse *ch;
+
+ list_for_each_entry(ch, &channels_inuse, list) {
+ if (ch->ic == ic)
+ goto found;
+ }
+ ch = NULL;
+found:
+ if (c && (c != IEEE80211_CHAN_ANYC)) {
+ if (!ch) {
+ ch = kmalloc(sizeof(struct channel_inuse), GFP_ATOMIC);
+ ch->ic = ic;
+ INIT_LIST_HEAD(&ch->list);
+ list_add(&ch->list, &channels_inuse);
+ }
+ ch->freq = c->ic_freq;
+ ch->bw = get_channel_bw(c);
+ } else if (ch) {
+ list_del(&ch->list);
+ kfree(ch);
+ }
+}
+EXPORT_SYMBOL(ieee80211_scan_set_bss_channel);
+
+
void
ieee80211_scan_attach(struct ieee80211com *ic)
{
@@ -1155,7 +1272,7 @@ ieee80211_scan_dfs_action(struct ieee802
IEEE80211_RADAR_CHANCHANGE_TBTT_COUNT;
ic->ic_flags |= IEEE80211_F_CHANSWITCH;
} else {
-
+ unsigned long flags;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_DOTH,
"%s: directly switching to channel "
"%3d (%4d MHz)\n", __func__,
@@ -1166,6 +1283,9 @@ ieee80211_scan_dfs_action(struct ieee802
* change the channel here. */
change_channel(ic, new_channel);
ic->ic_bsschan = new_channel;
+ spin_lock_irqsave(&channel_lock, flags);
+ ieee80211_scan_set_bss_channel(ic, ic->ic_bsschan);
+ spin_unlock_irqrestore(&channel_lock, flags);
if (vap->iv_bss)
vap->iv_bss->ni_chan = new_channel;
}
--- a/net80211/ieee80211_scan.h
+++ b/net80211/ieee80211_scan.h
@@ -35,6 +35,7 @@
#define IEEE80211_SCAN_MAX IEEE80211_CHAN_MAX
+extern spinlock_t channel_lock;
struct ieee80211_scanner;
struct ieee80211_scan_entry;
@@ -116,6 +117,8 @@ void ieee80211_scan_flush(struct ieee802
struct ieee80211_scan_entry;
typedef int ieee80211_scan_iter_func(void *, const struct ieee80211_scan_entry *);
int ieee80211_scan_iterate(struct ieee80211com *, ieee80211_scan_iter_func *, void *);
+u32 ieee80211_scan_get_bias(struct ieee80211_channel *c);
+void ieee80211_scan_set_bss_channel(struct ieee80211com *ic, struct ieee80211_channel *c);
/*
* Parameters supplied when adding/updating an entry in a
--- a/net80211/ieee80211.c
+++ b/net80211/ieee80211.c
@@ -373,8 +373,16 @@ void
ieee80211_ifdetach(struct ieee80211com *ic)
{
struct ieee80211vap *vap;
+ unsigned long flags;
int count;
+ /* mark the channel as no longer in use */
+ ic->ic_bsschan = IEEE80211_CHAN_ANYC;
+ spin_lock_irqsave(&channel_lock, flags);
+ ieee80211_scan_set_bss_channel(ic, ic->ic_bsschan);
+ spin_unlock_irqrestore(&channel_lock, flags);
+
+
/* bring down all vaps */
TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) {
ieee80211_stop(vap->iv_dev);
--- a/net80211/ieee80211_input.c
+++ b/net80211/ieee80211_input.c
@@ -2772,6 +2772,7 @@ static void
ieee80211_doth_switch_channel(struct ieee80211vap *vap)
{
struct ieee80211com *ic = vap->iv_ic;
+ unsigned long flags;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_DOTH,
"%s: Channel switch to %3d (%4d MHz) NOW!\n",
@@ -2794,6 +2795,9 @@ ieee80211_doth_switch_channel(struct iee
ic->ic_curchan = ic->ic_bsschan = vap->iv_csa_chan;
ic->ic_set_channel(ic);
+ spin_lock_irqsave(&channel_lock, flags);
+ ieee80211_scan_set_bss_channel(ic, ic->ic_bsschan);
+ spin_unlock_irqrestore(&channel_lock, flags);
}
static void
--- a/net80211/ieee80211_node.c
+++ b/net80211/ieee80211_node.c
@@ -308,6 +308,7 @@ ieee80211_create_ibss(struct ieee80211va
{
struct ieee80211com *ic = vap->iv_ic;
struct ieee80211_node *ni;
+ unsigned long flags;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_SCAN,
"%s: creating ibss on channel %u\n", __func__,
@@ -386,6 +387,9 @@ ieee80211_create_ibss(struct ieee80211va
ic->ic_bsschan = chan;
ieee80211_node_set_chan(ic, ni);
ic->ic_curmode = ieee80211_chan2mode(chan);
+ spin_lock_irqsave(&channel_lock, flags);
+ ieee80211_scan_set_bss_channel(ic, ic->ic_bsschan);
+ spin_unlock_irqrestore(&channel_lock, flags);
/* Update country ie information */
ieee80211_build_countryie(ic);
@@ -622,6 +626,7 @@ ieee80211_sta_join1(struct ieee80211_nod
struct ieee80211vap *vap = selbs->ni_vap;
struct ieee80211com *ic = selbs->ni_ic;
struct ieee80211_node *obss;
+ unsigned long flags;
int canreassoc;
if (vap->iv_opmode == IEEE80211_M_IBSS) {
@@ -650,6 +655,9 @@ ieee80211_sta_join1(struct ieee80211_nod
ic->ic_curchan = ic->ic_bsschan;
ic->ic_curmode = ieee80211_chan2mode(ic->ic_curchan);
ic->ic_set_channel(ic);
+ spin_lock_irqsave(&channel_lock, flags);
+ ieee80211_scan_set_bss_channel(ic, ic->ic_bsschan);
+ spin_unlock_irqrestore(&channel_lock, flags);
/*
* Set the erp state (mostly the slot time) to deal with
* the auto-select case; this should be redundant if the
--- a/net80211/ieee80211_proto.c
+++ b/net80211/ieee80211_proto.c
@@ -1225,6 +1225,7 @@ ieee80211_dturbo_switch(struct ieee80211
struct ieee80211vap *vap = TAILQ_FIRST(&ic->ic_vaps);
#endif
struct ieee80211_channel *chan;
+ unsigned long flags;
chan = ieee80211_find_channel(ic, ic->ic_bsschan->ic_freq, newflags);
if (chan == NULL) { /* XXX should not happen */
@@ -1243,6 +1244,9 @@ ieee80211_dturbo_switch(struct ieee80211
ic->ic_bsschan = chan;
ic->ic_curchan = chan;
ic->ic_set_channel(ic);
+ spin_lock_irqsave(&channel_lock, flags);
+ ieee80211_scan_set_bss_channel(ic, ic->ic_bsschan);
+ spin_unlock_irqrestore(&channel_lock, flags);
/* NB: do not need to reset ERP state because in sta mode */
}
EXPORT_SYMBOL(ieee80211_dturbo_switch);
--- a/net80211/ieee80211_wireless.c
+++ b/net80211/ieee80211_wireless.c
@@ -4076,8 +4076,13 @@ ieee80211_ioctl_setchanlist(struct net_d
if (nchan == 0) /* no valid channels, disallow */
return -EINVAL;
if (ic->ic_bsschan != IEEE80211_CHAN_ANYC && /* XXX */
- isclr(chanlist, ic->ic_bsschan->ic_ieee))
+ isclr(chanlist, ic->ic_bsschan->ic_ieee)) {
+ unsigned long flags;
ic->ic_bsschan = IEEE80211_CHAN_ANYC; /* invalidate */
+ spin_lock_irqsave(&channel_lock, flags);
+ ieee80211_scan_set_bss_channel(ic, ic->ic_bsschan);
+ spin_unlock_irqrestore(&channel_lock, flags);
+ }
memcpy(ic->ic_chan_active, chanlist, sizeof(ic->ic_chan_active));
/* update Supported Channels information element */
--- a/net80211/ieee80211_scan_ap.c
+++ b/net80211/ieee80211_scan_ap.c
@@ -213,9 +213,15 @@ ap_start(struct ieee80211_scan_state *ss
struct ieee80211com *ic = NULL;
int i;
unsigned int mode = 0;
+ unsigned long sflags;
SCAN_AP_LOCK_IRQ(as);
ic = vap->iv_ic;
+
+ spin_lock_irqsave(&channel_lock, sflags);
+ ieee80211_scan_set_bss_channel(ic, NULL);
+ spin_unlock_irqrestore(&channel_lock, sflags);
+
/* Determine mode flags to match, or leave zero for auto mode */
as->as_vap_desired_mode = vap->iv_des_mode;
as->as_required_mode = 0;
@@ -429,8 +435,10 @@ pc_cmp_idletime(struct ieee80211_channel
if (!a->ic_idletime || !b->ic_idletime)
return 0;
- /* a is better than b (return < 0) when a has more idle time than b */
- return b->ic_idletime - a->ic_idletime;
+ /* a is better than b (return < 0) when a has more idle and less bias time than b */
+ return
+ ((100 - (u32) a->ic_idletime) + ieee80211_scan_get_bias(a)) -
+ ((100 - (u32) b->ic_idletime) + ieee80211_scan_get_bias(b));
}
@@ -616,6 +624,7 @@ ap_end(struct ieee80211_scan_state *ss,
struct ap_state *as = ss->ss_priv;
struct ieee80211_channel *bestchan = NULL;
struct ieee80211com *ic = NULL;
+ unsigned long sflags;
int res = 1;
SCAN_AP_LOCK_IRQ(as);
@@ -624,8 +633,11 @@ ap_end(struct ieee80211_scan_state *ss,
("wrong opmode %u", vap->iv_opmode));
ic = vap->iv_ic;
+ spin_lock_irqsave(&channel_lock, sflags);
+ ieee80211_scan_set_bss_channel(ic, NULL);
bestchan = pick_channel(ss, vap, flags);
if (bestchan == NULL) {
+ spin_unlock_irqrestore(&channel_lock, sflags);
if (ss->ss_last > 0) {
/* no suitable channel, should not happen */
printk(KERN_ERR "%s: %s: no suitable channel! "
@@ -644,6 +656,7 @@ ap_end(struct ieee80211_scan_state *ss,
bestchan->ic_freq, bestchan->ic_flags &
~IEEE80211_CHAN_TURBO)) == NULL) {
/* should never happen ?? */
+ spin_unlock_irqrestore(&channel_lock, sflags);
SCAN_AP_UNLOCK_IRQ_EARLY(as);
return 0;
}
@@ -656,6 +669,9 @@ ap_end(struct ieee80211_scan_state *ss,
as->as_action = action;
as->as_selbss = se;
+ ieee80211_scan_set_bss_channel(ic, bestchan);
+ spin_unlock_irqrestore(&channel_lock, sflags);
+
/* Must defer action to avoid possible recursive call through
* 80211 state machine, which would result in recursive
* locking. */