mac80211_hwsim: Add support for client PS mode

This introduces a debugfs file (ieee80211/phy#/hwsim/ps) that can be
used to force a simulated radio into power save mode. Following values
can be written into this file to change PS mode:
0 = power save disabled (constantly awake)
1 = power save enabled (drop all frames; do not send PS-Poll)
2 = power save enabled (send PS-Poll frames automatically to receive
    buffered unicast frames); not yet fully implemented
3 = manual PS-Poll trigger (send a single PS-Poll frame)

Two different behavior for power save mode processing can be tested:
- move between modes 1 and 0 (i.e., receive all buffered frames at a
  time)
- move to mode 1 and use manual PS-Poll frames (write 3 to the 'ps'
  debugfs file) to fetch power save buffered frames one at a time

Mode 2 (automatic PS-Poll) does not yet parse Beacon frames, but
eventually, it should take a look at TIM IE and send PS-Poll if a
traffic bit is set for our AID.

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 191 insertions, 0 deletions

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index bc9da9393760..b9230da925ee 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -21,6 +21,7 @@
 #include <linux/if_arp.h>
 #include <linux/rtnetlink.h>
 #include <linux/etherdevice.h>
+#include <linux/debugfs.h>
 
 MODULE_AUTHOR("Jouni Malinen");
 MODULE_DESCRIPTION("Software simulator of 802.11 radio(s) for mac80211");
@@ -32,6 +33,9 @@ MODULE_PARM_DESC(radios, "Number of simulated radios");
 
 struct hwsim_vif_priv {
         u32 magic;
+        u8 bssid[ETH_ALEN];
+        bool assoc;
+        u16 aid;
 };
 
 #define HWSIM_VIF_MAGIC 0x69537748
@@ -132,6 +136,12 @@ struct mac80211_hwsim_data {
         unsigned int rx_filter;
         int started;
         struct timer_list beacon_timer;
+        enum ps_mode {
+                PS_DISABLED, PS_ENABLED, PS_AUTO_POLL, PS_MANUAL_POLL
+        } ps;
+        bool ps_poll_pending;
+        struct dentry *debugfs;
+        struct dentry *debugfs_ps;
 };
 
 
@@ -196,6 +206,34 @@ static void mac80211_hwsim_monitor_rx(struct ieee80211_hw *hw,
 }
 
 
+static bool hwsim_ps_rx_ok(struct mac80211_hwsim_data *data,
+                           struct sk_buff *skb)
+{
+        switch (data->ps) {
+        case PS_DISABLED:
+                return true;
+        case PS_ENABLED:
+                return false;
+        case PS_AUTO_POLL:
+                /* TODO: accept (some) Beacons by default and other frames only
+                 * if pending PS-Poll has been sent */
+                return true;
+        case PS_MANUAL_POLL:
+                /* Allow unicast frames to own address if there is a pending
+                 * PS-Poll */
+                if (data->ps_poll_pending &&
+                    memcmp(data->hw->wiphy->perm_addr, skb->data + 4,
+                           ETH_ALEN) == 0) {
+                        data->ps_poll_pending = false;
+                        return true;
+                }
+                return false;
+        }
+
+        return true;
+}
+
+
 static bool mac80211_hwsim_tx_frame(struct ieee80211_hw *hw,
                                     struct sk_buff *skb)
 {
@@ -212,6 +250,9 @@ static bool mac80211_hwsim_tx_frame(struct ieee80211_hw *hw,
         rx_status.rate_idx = info->control.rates[0].idx;
         /* TODO: simulate signal strength (and optional packet drop) */
 
+        if (data->ps != PS_DISABLED)
+                hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PM);
+
         /* Copy skb to all enabled radios that are on the current frequency */
         spin_lock(&hwsim_radio_lock);
         list_for_each_entry(data2, &hwsim_radios, list) {
@@ -221,6 +262,7 @@ static bool mac80211_hwsim_tx_frame(struct ieee80211_hw *hw,
                         continue;
 
                 if (!data2->started || !data2->radio_enabled ||
+                    !hwsim_ps_rx_ok(data2, skb) ||
                     data->channel->center_freq != data2->channel->center_freq)
                         continue;
 
@@ -404,7 +446,16 @@ static int mac80211_hwsim_config_interface(struct ieee80211_hw *hw,
                                            struct ieee80211_vif *vif,
                                            struct ieee80211_if_conf *conf)
 {
+        struct hwsim_vif_priv *vp = (void *)vif->drv_priv;
+
         hwsim_check_magic(vif);
+        if (conf->changed & IEEE80211_IFCC_BSSID) {
+                DECLARE_MAC_BUF(mac);
+                printk(KERN_DEBUG "%s:%s: BSSID changed: %s\n",
+                       wiphy_name(hw->wiphy), __func__,
+                       print_mac(mac, conf->bssid));
+                memcpy(vp->bssid, conf->bssid, ETH_ALEN);
+        }
         return 0;
 }
 
@@ -413,6 +464,8 @@ static void mac80211_hwsim_bss_info_changed(struct ieee80211_hw *hw,
                                             struct ieee80211_bss_conf *info,
                                             u32 changed)
 {
+        struct hwsim_vif_priv *vp = (void *)vif->drv_priv;
+
         hwsim_check_magic(vif);
 
         printk(KERN_DEBUG "%s:%s(changed=0x%x)\n",
@@ -421,6 +474,8 @@ static void mac80211_hwsim_bss_info_changed(struct ieee80211_hw *hw,
         if (changed & BSS_CHANGED_ASSOC) {
                 printk(KERN_DEBUG "  %s: ASSOC: assoc=%d aid=%d\n",
                        wiphy_name(hw->wiphy), info->assoc, info->aid);
+                vp->assoc = info->assoc;
+                vp->aid = info->aid;
         }
 
         if (changed & BSS_CHANGED_ERP_CTS_PROT) {
@@ -518,6 +573,8 @@ static void mac80211_hwsim_free(void)
         spin_unlock_bh(&hwsim_radio_lock);
 
         list_for_each_entry(data, &tmplist, list) {
+                debugfs_remove(data->debugfs_ps);
+                debugfs_remove(data->debugfs);
                 ieee80211_unregister_hw(data->hw);
                 device_unregister(data->dev);
                 ieee80211_free_hw(data->hw);
@@ -543,6 +600,127 @@ static void hwsim_mon_setup(struct net_device *dev)
 }
 
 
+static void hwsim_send_ps_poll(void *dat, u8 *mac, struct ieee80211_vif *vif)
+{
+        struct mac80211_hwsim_data *data = dat;
+        struct hwsim_vif_priv *vp = (void *)vif->drv_priv;
+        DECLARE_MAC_BUF(buf);
+        struct sk_buff *skb;
+        struct ieee80211_pspoll *pspoll;
+
+        if (!vp->assoc)
+                return;
+
+        printk(KERN_DEBUG "%s:%s: send PS-Poll to %s for aid %d\n",
+               wiphy_name(data->hw->wiphy), __func__,
+               print_mac(buf, vp->bssid), vp->aid);
+
+        skb = dev_alloc_skb(sizeof(*pspoll));
+        if (!skb)
+                return;
+        pspoll = (void *) skb_put(skb, sizeof(*pspoll));
+        pspoll->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
+                                            IEEE80211_STYPE_PSPOLL |
+                                            IEEE80211_FCTL_PM);
+        pspoll->aid = cpu_to_le16(0xc000 | vp->aid);
+        memcpy(pspoll->bssid, vp->bssid, ETH_ALEN);
+        memcpy(pspoll->ta, mac, ETH_ALEN);
+        if (data->radio_enabled &&
+            !mac80211_hwsim_tx_frame(data->hw, skb))
+                printk(KERN_DEBUG "%s: PS-Poll frame not ack'ed\n", __func__);
+        dev_kfree_skb(skb);
+}
+
+
+static void hwsim_send_nullfunc(struct mac80211_hwsim_data *data, u8 *mac,
+                                struct ieee80211_vif *vif, int ps)
+{
+        struct hwsim_vif_priv *vp = (void *)vif->drv_priv;
+        DECLARE_MAC_BUF(buf);
+        struct sk_buff *skb;
+        struct ieee80211_hdr *hdr;
+
+        if (!vp->assoc)
+                return;
+
+        printk(KERN_DEBUG "%s:%s: send data::nullfunc to %s ps=%d\n",
+               wiphy_name(data->hw->wiphy), __func__,
+               print_mac(buf, vp->bssid), ps);
+
+        skb = dev_alloc_skb(sizeof(*hdr));
+        if (!skb)
+                return;
+        hdr = (void *) skb_put(skb, sizeof(*hdr) - ETH_ALEN);
+        hdr->frame_control = cpu_to_le16(IEEE80211_FTYPE_DATA |
+                                         IEEE80211_STYPE_NULLFUNC |
+                                         (ps ? IEEE80211_FCTL_PM : 0));
+        hdr->duration_id = cpu_to_le16(0);
+        memcpy(hdr->addr1, vp->bssid, ETH_ALEN);
+        memcpy(hdr->addr2, mac, ETH_ALEN);
+        memcpy(hdr->addr3, vp->bssid, ETH_ALEN);
+        if (data->radio_enabled &&
+            !mac80211_hwsim_tx_frame(data->hw, skb))
+                printk(KERN_DEBUG "%s: nullfunc frame not ack'ed\n", __func__);
+        dev_kfree_skb(skb);
+}
+
+
+static void hwsim_send_nullfunc_ps(void *dat, u8 *mac,
+                                   struct ieee80211_vif *vif)
+{
+        struct mac80211_hwsim_data *data = dat;
+        hwsim_send_nullfunc(data, mac, vif, 1);
+}
+
+
+static void hwsim_send_nullfunc_no_ps(void *dat, u8 *mac,
+                                      struct ieee80211_vif *vif)
+{
+        struct mac80211_hwsim_data *data = dat;
+        hwsim_send_nullfunc(data, mac, vif, 0);
+}
+
+
+static int hwsim_fops_ps_read(void *dat, u64 *val)
+{
+        struct mac80211_hwsim_data *data = dat;
+        *val = data->ps;
+        return 0;
+}
+
+static int hwsim_fops_ps_write(void *dat, u64 val)
+{
+        struct mac80211_hwsim_data *data = dat;
+        enum ps_mode old_ps;
+
+        if (val != PS_DISABLED && val != PS_ENABLED && val != PS_AUTO_POLL &&
+            val != PS_MANUAL_POLL)
+                return -EINVAL;
+
+        old_ps = data->ps;
+        data->ps = val;
+
+        if (val == PS_MANUAL_POLL) {
+                ieee80211_iterate_active_interfaces(data->hw,
+                                                    hwsim_send_ps_poll, data);
+                data->ps_poll_pending = true;
+        } else if (old_ps == PS_DISABLED && val != PS_DISABLED) {
+                ieee80211_iterate_active_interfaces(data->hw,
+                                                    hwsim_send_nullfunc_ps,
+                                                    data);
+        } else if (old_ps != PS_DISABLED && val == PS_DISABLED) {
+                ieee80211_iterate_active_interfaces(data->hw,
+                                                    hwsim_send_nullfunc_no_ps,
+                                                    data);
+        }
+
+        return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(hwsim_fops_ps, hwsim_fops_ps_read, hwsim_fops_ps_write,
+                        "%llu\n");
+
+
 static int __init init_mac80211_hwsim(void)
 {
         int i, err = 0;
@@ -634,6 +812,12 @@ static int __init init_mac80211_hwsim(void)
                        wiphy_name(hw->wiphy),
                        hw->wiphy->perm_addr);
 
+                data->debugfs = debugfs_create_dir("hwsim",
+                                                   hw->wiphy->debugfsdir);
+                data->debugfs_ps = debugfs_create_file("ps", 0666,
+                                                       data->debugfs, data,
+                                                       &hwsim_fops_ps);
+
                 setup_timer(&data->beacon_timer, mac80211_hwsim_beacon,
                             (unsigned long) hw);
 
diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 9dc288b920c8..56b0eb25d927 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -669,6 +669,13 @@ struct ieee80211_cts {
         u8 ra[6];
 } __attribute__ ((packed));
 
+struct ieee80211_pspoll {
+        __le16 frame_control;
+        __le16 aid;
+        u8 bssid[6];
+        u8 ta[6];
+} __attribute__ ((packed));
+
 /**
  * struct ieee80211_bar - HT Block Ack Request
  *