mac80211: add functions to create PS Poll and Nullfunc templates

Some hardware, for example wl1251 and wl1271, handle the transmission
of power save related frames in hardware, but the driver is responsible
for creating the templates. It's better to create the templates in mac80211,
that way all drivers can benefit from this.

Add two new functions, ieee80211_pspoll_get() and ieee80211_nullfunc_get()
which drivers need to call to get the frame. Drivers are also responsible
for updating the templates after each association.

Also new struct ieee80211_hdr_3addr is added to ieee80211.h to make it
easy to calculate length of the Nullfunc frame.
Signed-off-by: Kalle Valo <kalle.valo@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/linux/ieee80211.h

@@ -130,6 +130,15 @@ struct ieee80211_hdr {
 	u8 addr4[6];
 } __attribute__ ((packed));
 
+struct ieee80211_hdr_3addr {
+	__le16 frame_control;
+	__le16 duration_id;
+	u8 addr1[6];
+	u8 addr2[6];
+	u8 addr3[6];
+	__le16 seq_ctrl;
+} __attribute__ ((packed));
+
 /**
  * ieee80211_has_tods - check if IEEE80211_FCTL_TODS is set
  * @fc: frame control bytes in little-endian byteorder

include/net/mac80211.h

@@ -1874,6 +1874,36 @@ static inline struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
 	return ieee80211_beacon_get_tim(hw, vif, NULL, NULL);
 }
 
+/**
+ * ieee80211_pspoll_get - retrieve a PS Poll template
+ * @hw: pointer obtained from ieee80211_alloc_hw().
+ * @vif: &struct ieee80211_vif pointer from the add_interface callback.
+ *
+ * Creates a PS Poll a template which can, for example, uploaded to
+ * hardware. The template must be updated after association so that correct
+ * AID, BSSID and MAC address is used.
+ *
+ * Note: Caller (or hardware) is responsible for setting the
+ * &IEEE80211_FCTL_PM bit.
+ */
+struct sk_buff *ieee80211_pspoll_get(struct ieee80211_hw *hw,
+				     struct ieee80211_vif *vif);
+
+/**
+ * ieee80211_nullfunc_get - retrieve a nullfunc template
+ * @hw: pointer obtained from ieee80211_alloc_hw().
+ * @vif: &struct ieee80211_vif pointer from the add_interface callback.
+ *
+ * Creates a Nullfunc template which can, for example, uploaded to
+ * hardware. The template must be updated after association so that correct
+ * BSSID and address is used.
+ *
+ * Note: Caller (or hardware) is responsible for setting the
+ * &IEEE80211_FCTL_PM bit as well as Duration and Sequence Control fields.
+ */
+struct sk_buff *ieee80211_nullfunc_get(struct ieee80211_hw *hw,
+				       struct ieee80211_vif *vif);
+
 /**
  * ieee80211_rts_get - RTS frame generation function
  * @hw: pointer obtained from ieee80211_alloc_hw().

net/mac80211/tx.c

@@ -2200,6 +2200,84 @@ struct sk_buff *ieee80211_beacon_get_tim(struct ieee80211_hw *hw,
 }
 EXPORT_SYMBOL(ieee80211_beacon_get_tim);
 
+struct sk_buff *ieee80211_pspoll_get(struct ieee80211_hw *hw,
+				     struct ieee80211_vif *vif)
+{
+	struct ieee80211_sub_if_data *sdata;
+	struct ieee80211_if_managed *ifmgd;
+	struct ieee80211_pspoll *pspoll;
+	struct ieee80211_local *local;
+	struct sk_buff *skb;
+
+	if (WARN_ON(vif->type != NL80211_IFTYPE_STATION))
+		return NULL;
+
+	sdata = vif_to_sdata(vif);
+	ifmgd = &sdata->u.mgd;
+	local = sdata->local;
+
+	skb = dev_alloc_skb(local->hw.extra_tx_headroom + sizeof(*pspoll));
+	if (!skb) {
+		printk(KERN_DEBUG "%s: failed to allocate buffer for "
+		       "pspoll template\n", sdata->name);
+		return NULL;
+	}
+	skb_reserve(skb, local->hw.extra_tx_headroom);
+
+	pspoll = (struct ieee80211_pspoll *) skb_put(skb, sizeof(*pspoll));
+	memset(pspoll, 0, sizeof(*pspoll));
+	pspoll->frame_control = cpu_to_le16(IEEE80211_FTYPE_CTL |
+					    IEEE80211_STYPE_PSPOLL);
+	pspoll->aid = cpu_to_le16(ifmgd->aid);
+
+	/* aid in PS-Poll has its two MSBs each set to 1 */
+	pspoll->aid |= cpu_to_le16(1 << 15 | 1 << 14);
+
+	memcpy(pspoll->bssid, ifmgd->bssid, ETH_ALEN);
+	memcpy(pspoll->ta, vif->addr, ETH_ALEN);
+
+	return skb;
+}
+EXPORT_SYMBOL(ieee80211_pspoll_get);
+
+struct sk_buff *ieee80211_nullfunc_get(struct ieee80211_hw *hw,
+				       struct ieee80211_vif *vif)
+{
+	struct ieee80211_hdr_3addr *nullfunc;
+	struct ieee80211_sub_if_data *sdata;
+	struct ieee80211_if_managed *ifmgd;
+	struct ieee80211_local *local;
+	struct sk_buff *skb;
+
+	if (WARN_ON(vif->type != NL80211_IFTYPE_STATION))
+		return NULL;
+
+	sdata = vif_to_sdata(vif);
+	ifmgd = &sdata->u.mgd;
+	local = sdata->local;
+
+	skb = dev_alloc_skb(local->hw.extra_tx_headroom + sizeof(*nullfunc));
+	if (!skb) {
+		printk(KERN_DEBUG "%s: failed to allocate buffer for nullfunc "
+		       "template\n", sdata->name);
+		return NULL;
+	}
+	skb_reserve(skb, local->hw.extra_tx_headroom);
+
+	nullfunc = (struct ieee80211_hdr_3addr *) skb_put(skb,
+							  sizeof(*nullfunc));
+	memset(nullfunc, 0, sizeof(*nullfunc));
+	nullfunc->frame_control = cpu_to_le16(IEEE80211_FTYPE_DATA |
+					      IEEE80211_STYPE_NULLFUNC |
+					      IEEE80211_FCTL_TODS);
+	memcpy(nullfunc->addr1, ifmgd->bssid, ETH_ALEN);
+	memcpy(nullfunc->addr2, vif->addr, ETH_ALEN);
+	memcpy(nullfunc->addr3, ifmgd->bssid, ETH_ALEN);
+
+	return skb;
+}
+EXPORT_SYMBOL(ieee80211_nullfunc_get);
+
 void ieee80211_rts_get(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 		       const void *frame, size_t frame_len,
 		       const struct ieee80211_tx_info *frame_txctl,