--- /dev/null
+/*
+ * Copyright 2002-2004, Instant802 Networks, Inc.
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/skbuff.h>
+
+#include <net/d80211.h>
+#include "ieee80211_i.h"
+#include "ieee80211_rate.h"
+
+
+/* Maximum number of seconds to wait for the traffic load to get below
+ * threshold before forcing a passive scan. */
+#define MAX_SCAN_WAIT 60
+/* Threshold (pkts/sec TX or RX) for delaying passive scan */
+#define SCAN_TXRX_THRESHOLD 75
+
+static void get_channel_params(struct ieee80211_local *local, int channel,
+ struct ieee80211_hw_modes **mode,
+ struct ieee80211_channel **chan)
+{
+ int m;
+
+ for (m = 0; m < local->hw.num_modes; m++) {
+ *mode = &local->hw.modes[m];
+ if ((*mode)->mode == local->hw.conf.phymode)
+ break;
+ }
+ local->scan.mode_idx = m;
+ local->scan.chan_idx = 0;
+ do {
+ *chan = &(*mode)->channels[local->scan.chan_idx];
+ if ((*chan)->chan == channel) {
+ return;
+ }
+ local->scan.chan_idx++;
+ } while (local->scan.chan_idx < (*mode)->num_channels);
+ *chan = NULL;
+}
+
+
+static void next_chan_same_mode(struct ieee80211_local *local,
+ struct ieee80211_hw_modes **mode,
+ struct ieee80211_channel **chan)
+{
+ int m, prev;
+
+ for (m = 0; m < local->hw.num_modes; m++) {
+ *mode = &local->hw.modes[m];
+ if ((*mode)->mode == local->hw.conf.phymode)
+ break;
+ }
+ local->scan.mode_idx = m;
+
+ /* Select next channel - scan only channels marked with W_SCAN flag */
+ prev = local->scan.chan_idx;
+ do {
+ local->scan.chan_idx++;
+ if (local->scan.chan_idx >= (*mode)->num_channels)
+ local->scan.chan_idx = 0;
+ *chan = &(*mode)->channels[local->scan.chan_idx];
+ if ((*chan)->flag & IEEE80211_CHAN_W_SCAN)
+ break;
+ } while (local->scan.chan_idx != prev);
+}
+
+
+static void next_chan_all_modes(struct ieee80211_local *local,
+ struct ieee80211_hw_modes **mode,
+ struct ieee80211_channel **chan)
+{
+ int prev, prev_m;
+
+ if (local->scan.mode_idx >= local->hw.num_modes) {
+ local->scan.mode_idx = 0;
+ local->scan.chan_idx = 0;
+ }
+
+ /* Select next channel - scan only channels marked with W_SCAN flag */
+ prev = local->scan.chan_idx;
+ prev_m = local->scan.mode_idx;
+ do {
+ *mode = &local->hw.modes[local->scan.mode_idx];
+ local->scan.chan_idx++;
+ if (local->scan.chan_idx >= (*mode)->num_channels) {
+ local->scan.chan_idx = 0;
+ local->scan.mode_idx++;
+ if (local->scan.mode_idx >= local->hw.num_modes)
+ local->scan.mode_idx = 0;
+ *mode = &local->hw.modes[local->scan.mode_idx];
+ }
+ *chan = &(*mode)->channels[local->scan.chan_idx];
+ if ((*chan)->flag & IEEE80211_CHAN_W_SCAN)
+ break;
+ } while (local->scan.chan_idx != prev ||
+ local->scan.mode_idx != prev_m);
+}
+
+
+static void ieee80211_scan_start(struct ieee80211_local *local,
+ struct ieee80211_scan_conf *conf)
+{
+ int old_mode_idx = local->scan.mode_idx;
+ int old_chan_idx = local->scan.chan_idx;
+ struct ieee80211_hw_modes *mode = NULL;
+ struct ieee80211_channel *chan = NULL;
+ int ret;
+
+ if (!local->ops->passive_scan) {
+ printk(KERN_DEBUG "%s: Scan handler called, yet the hardware "
+ "does not support passive scanning. Disabled.\n",
+ local->mdev->name);
+ return;
+ }
+
+ if ((local->scan.tries < MAX_SCAN_WAIT &&
+ local->scan.txrx_count > SCAN_TXRX_THRESHOLD)) {
+ local->scan.tries++;
+ /* Count TX/RX packets during one second interval and allow
+ * scan to start only if the number of packets is below the
+ * threshold. */
+ local->scan.txrx_count = 0;
+ local->scan.timer.expires = jiffies + HZ;
+ add_timer(&local->scan.timer);
+ return;
+ }
+
+ if (!local->scan.skb) {
+ printk(KERN_DEBUG "%s: Scan start called even though scan.skb "
+ "is not set\n", local->mdev->name);
+ }
+
+ if (local->scan.our_mode_only) {
+ if (local->scan.channel > 0) {
+ get_channel_params(local, local->scan.channel, &mode,
+ &chan);
+ } else
+ next_chan_same_mode(local, &mode, &chan);
+ }
+ else
+ next_chan_all_modes(local, &mode, &chan);
+
+ conf->scan_channel = chan->chan;
+ conf->scan_freq = chan->freq;
+ conf->scan_channel_val = chan->val;
+ conf->scan_phymode = mode->mode;
+ conf->scan_power_level = chan->power_level;
+ conf->scan_antenna_max = chan->antenna_max;
+ conf->scan_time = 2 * local->hw.channel_change_time +
+ local->scan.time; /* 10ms scan time+hardware changes */
+ conf->skb = local->scan.skb ?
+ skb_clone(local->scan.skb, GFP_ATOMIC) : NULL;
+ conf->tx_control = &local->scan.tx_control;
+#if 0
+ printk(KERN_DEBUG "%s: Doing scan on mode: %d freq: %d chan: %d "
+ "for %d ms\n",
+ local->mdev->name, conf->scan_phymode, conf->scan_freq,
+ conf->scan_channel, conf->scan_time);
+#endif
+ local->scan.rx_packets = 0;
+ local->scan.rx_beacon = 0;
+ local->scan.freq = chan->freq;
+ local->scan.in_scan = 1;
+
+ ieee80211_netif_oper(local_to_hw(local), NETIF_STOP);
+
+ ret = local->ops->passive_scan(local_to_hw(local),
+ IEEE80211_SCAN_START, conf);
+
+ if (ret == 0) {
+ long usec = local->hw.channel_change_time +
+ local->scan.time;
+ usec += 1000000L / HZ - 1;
+ usec /= 1000000L / HZ;
+ local->scan.timer.expires = jiffies + usec;
+ } else {
+ local->scan.in_scan = 0;
+ if (conf->skb)
+ dev_kfree_skb(conf->skb);
+ ieee80211_netif_oper(local_to_hw(local), NETIF_WAKE);
+ if (ret == -EAGAIN) {
+ local->scan.timer.expires = jiffies +
+ (local->scan.interval * HZ / 100);
+ local->scan.mode_idx = old_mode_idx;
+ local->scan.chan_idx = old_chan_idx;
+ } else {
+ printk(KERN_DEBUG "%s: Got unknown error from "
+ "passive_scan %d\n", local->mdev->name, ret);
+ local->scan.timer.expires = jiffies +
+ (local->scan.interval * HZ);
+ }
+ local->scan.in_scan = 0;
+ }
+
+ add_timer(&local->scan.timer);
+}
+
+
+static void ieee80211_scan_stop(struct ieee80211_local *local,
+ struct ieee80211_scan_conf *conf)
+{
+ struct ieee80211_hw_modes *mode;
+ struct ieee80211_channel *chan;
+ int wait;
+
+ if (!local->ops->passive_scan)
+ return;
+
+ if (local->scan.mode_idx >= local->hw.num_modes) {
+ local->scan.mode_idx = 0;
+ local->scan.chan_idx = 0;
+ }
+
+ mode = &local->hw.modes[local->scan.mode_idx];
+
+ if (local->scan.chan_idx >= mode->num_channels) {
+ local->scan.chan_idx = 0;
+ }
+
+ chan = &mode->channels[local->scan.chan_idx];
+
+ local->ops->passive_scan(local_to_hw(local), IEEE80211_SCAN_END,
+ conf);
+
+#ifdef CONFIG_D80211_VERBOSE_DEBUG
+ printk(KERN_DEBUG "%s: Did scan on mode: %d freq: %d chan: %d "
+ "GOT: %d Beacon: %d (%d)\n",
+ local->mdev->name,
+ mode->mode, chan->freq, chan->chan,
+ local->scan.rx_packets, local->scan.rx_beacon,
+ local->scan.tries);
+#endif /* CONFIG_D80211_VERBOSE_DEBUG */
+ local->scan.num_scans++;
+
+ local->scan.in_scan = 0;
+ ieee80211_netif_oper(local_to_hw(local), NETIF_WAKE);
+
+ local->scan.tries = 0;
+ /* Use random interval of scan.interval .. 2 * scan.interval */
+ wait = (local->scan.interval * HZ * ((net_random() & 127) + 128)) /
+ 128;
+ local->scan.timer.expires = jiffies + wait;
+
+ add_timer(&local->scan.timer);
+}
+
+
+static void ieee80211_scan_handler(unsigned long ullocal)
+{
+ struct ieee80211_local *local = (struct ieee80211_local *) ullocal;
+ struct ieee80211_scan_conf conf;
+
+ if (local->scan.interval == 0 && !local->scan.in_scan) {
+ /* Passive scanning is disabled - keep the timer always
+ * running to make code cleaner. */
+ local->scan.timer.expires = jiffies + 10 * HZ;
+ add_timer(&local->scan.timer);
+ return;
+ }
+
+ memset(&conf, 0, sizeof(struct ieee80211_scan_conf));
+ conf.running_freq = local->hw.conf.freq;
+ conf.running_channel = local->hw.conf.channel;
+ conf.running_phymode = local->hw.conf.phymode;
+ conf.running_channel_val = local->hw.conf.channel_val;
+ conf.running_power_level = local->hw.conf.power_level;
+ conf.running_antenna_max = local->hw.conf.antenna_max;
+
+ if (local->scan.in_scan == 0)
+ ieee80211_scan_start(local, &conf);
+ else
+ ieee80211_scan_stop(local, &conf);
+}
+
+
+void ieee80211_init_scan(struct ieee80211_local *local)
+{
+ struct ieee80211_hdr hdr;
+ u16 fc;
+ int len = 10;
+ struct rate_control_extra extra;
+
+ /* Only initialize passive scanning if the hardware supports it */
+ if (!local->ops->passive_scan) {
+ local->scan.skb = NULL;
+ memset(&local->scan.tx_control, 0,
+ sizeof(local->scan.tx_control));
+ printk(KERN_DEBUG "%s: Does not support passive scan, "
+ "disabled\n", local->mdev->name);
+ return;
+ }
+
+ local->scan.interval = 0;
+ local->scan.our_mode_only = 1;
+ local->scan.time = 10000;
+ local->scan.timer.function = ieee80211_scan_handler;
+ local->scan.timer.data = (unsigned long) local;
+ local->scan.timer.expires = jiffies + local->scan.interval * HZ;
+ add_timer(&local->scan.timer);
+
+ /* Create a CTS from for broadcasting before
+ * the low level changes channels */
+ local->scan.skb = alloc_skb(len, GFP_KERNEL);
+ if (!local->scan.skb) {
+ printk(KERN_WARNING "%s: Failed to allocate CTS packet for "
+ "passive scan\n", local->mdev->name);
+ return;
+ }
+
+ fc = IEEE80211_FTYPE_CTL | IEEE80211_STYPE_CTS;
+ hdr.frame_control = cpu_to_le16(fc);
+ hdr.duration_id =
+ cpu_to_le16(2 * local->hw.channel_change_time +
+ local->scan.time);
+ memcpy(hdr.addr1, local->mdev->dev_addr, ETH_ALEN); /* DA */
+ hdr.seq_ctrl = 0;
+
+ memcpy(skb_put(local->scan.skb, len), &hdr, len);
+
+ memset(&local->scan.tx_control, 0, sizeof(local->scan.tx_control));
+ local->scan.tx_control.key_idx = HW_KEY_IDX_INVALID;
+ local->scan.tx_control.flags |= IEEE80211_TXCTL_DO_NOT_ENCRYPT;
+ memset(&extra, 0, sizeof(extra));
+ extra.endidx = local->num_curr_rates;
+ local->scan.tx_control.tx_rate =
+ rate_control_get_rate(local, local->mdev,
+ local->scan.skb, &extra)->val;
+ local->scan.tx_control.flags |= IEEE80211_TXCTL_NO_ACK;
+}
+
+
+void ieee80211_stop_scan(struct ieee80211_local *local)
+{
+ if (local->ops->passive_scan) {
+ del_timer_sync(&local->scan.timer);
+ dev_kfree_skb(local->scan.skb);
+ local->scan.skb = NULL;
+ }
+}
projects / openwrt / openwrt.git / blobdiff