{nl,cfg,mac}80211: implement mesh channel switch userspace API

Implement the required procedures for mesh channel switching as defined
in the IEEE Std 802.11-2012 section 10.9.8.4.3 and also handle the CSA
and MCSP elements as followed:
 * Add the function for updating the beacon and probe response frames
   with CSA and MCSP elements during the period of switching to the new
   channel. Both CSA and MCSP elements must be included in beacon and
   probe response frames until the intended channel switch time.
 * The ifmsh->csa_settings is set to NULL and the CSA and MCSP elements
   will then be removed from the beacon or probe response frames once the
   new channel is switched to.

Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@cozybit.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 98 insertions, 0 deletions

diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c
index 0a3ccaa275f9..6eb31d6fd8e1 100644
--- a/net/mac80211/mesh.c
+++ b/net/mac80211/mesh.c
@@ -12,6 +12,7 @@
 #include <asm/unaligned.h>
 #include "ieee80211_i.h"
 #include "mesh.h"
+#include "driver-ops.h"
 
 static int mesh_allocated;
 static struct kmem_cache *rm_cache;
@@ -610,6 +611,7 @@ ieee80211_mesh_build_beacon(struct ieee80211_if_mesh *ifmsh)
 	struct sk_buff *skb;
 	struct ieee80211_mgmt *mgmt;
 	struct ieee80211_chanctx_conf *chanctx_conf;
+	struct mesh_csa_settings *csa;
 	enum ieee80211_band band;
 	u8 *pos;
 	struct ieee80211_sub_if_data *sdata;
@@ -624,6 +626,10 @@ ieee80211_mesh_build_beacon(struct ieee80211_if_mesh *ifmsh)
 
 	head_len = hdr_len +
 		   2 + /* NULL SSID */
+		   /* Channel Switch Announcement */
+		   2 + sizeof(struct ieee80211_channel_sw_ie) +
+		   /* Mesh Channel Swith Parameters */
+		   2 + sizeof(struct ieee80211_mesh_chansw_params_ie) +
 		   2 + 8 + /* supported rates */
 		   2 + 3; /* DS params */
 	tail_len = 2 + (IEEE80211_MAX_SUPP_RATES - 8) +
@@ -665,6 +671,38 @@ ieee80211_mesh_build_beacon(struct ieee80211_if_mesh *ifmsh)
 	*pos++ = WLAN_EID_SSID;
 	*pos++ = 0x0;
 
+	rcu_read_lock();
+	csa = rcu_dereference(ifmsh->csa);
+	if (csa) {
+		__le16 pre_value;
+
+		pos = skb_put(skb, 13);
+		memset(pos, 0, 13);
+		*pos++ = WLAN_EID_CHANNEL_SWITCH;
+		*pos++ = 3;
+		*pos++ = 0x0;
+		*pos++ = ieee80211_frequency_to_channel(
+				csa->settings.chandef.chan->center_freq);
+		sdata->csa_counter_offset_beacon = hdr_len + 6;
+		*pos++ = csa->settings.count;
+		*pos++ = WLAN_EID_CHAN_SWITCH_PARAM;
+		*pos++ = 6;
+		if (ifmsh->chsw_init) {
+			*pos++ = ifmsh->mshcfg.dot11MeshTTL;
+			*pos |= WLAN_EID_CHAN_SWITCH_PARAM_INITIATOR;
+		} else {
+			*pos++ = ifmsh->chsw_ttl;
+		}
+		*pos++ |= csa->settings.block_tx ?
+			  WLAN_EID_CHAN_SWITCH_PARAM_TX_RESTRICT : 0x00;
+		put_unaligned_le16(WLAN_REASON_MESH_CHAN, pos);
+		pos += 2;
+		pre_value = cpu_to_le16(ifmsh->pre_value);
+		memcpy(pos, &pre_value, 2);
+		pos += 2;
+	}
+	rcu_read_unlock();
+
 	if (ieee80211_add_srates_ie(sdata, skb, true, band) ||
 	    mesh_add_ds_params_ie(sdata, skb))
 		goto out_free;
@@ -920,6 +958,65 @@ static void ieee80211_mesh_rx_bcn_presp(struct ieee80211_sub_if_data *sdata,
 			stype, mgmt, &elems, rx_status);
 }
 
+int ieee80211_mesh_finish_csa(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+	struct mesh_csa_settings *tmp_csa_settings;
+	int ret = 0;
+
+	/* Reset the TTL value and Initiator flag */
+	ifmsh->chsw_init = false;
+	ifmsh->chsw_ttl = 0;
+
+	/* Remove the CSA and MCSP elements from the beacon */
+	tmp_csa_settings = rcu_dereference(ifmsh->csa);
+	rcu_assign_pointer(ifmsh->csa, NULL);
+	kfree_rcu(tmp_csa_settings, rcu_head);
+	ret = ieee80211_mesh_rebuild_beacon(sdata);
+	if (ret)
+		return -EINVAL;
+
+	ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
+
+	mcsa_dbg(sdata, "complete switching to center freq %d MHz",
+		 sdata->vif.bss_conf.chandef.chan->center_freq);
+	return 0;
+}
+
+int ieee80211_mesh_csa_beacon(struct ieee80211_sub_if_data *sdata,
+			      struct cfg80211_csa_settings *csa_settings,
+			      bool csa_action)
+{
+	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
+	struct mesh_csa_settings *tmp_csa_settings;
+	int ret = 0;
+
+	tmp_csa_settings = kmalloc(sizeof(*tmp_csa_settings),
+				   GFP_ATOMIC);
+	if (!tmp_csa_settings)
+		return -ENOMEM;
+
+	memcpy(&tmp_csa_settings->settings, csa_settings,
+	       sizeof(struct cfg80211_csa_settings));
+
+	rcu_assign_pointer(ifmsh->csa, tmp_csa_settings);
+
+	ret = ieee80211_mesh_rebuild_beacon(sdata);
+	if (ret) {
+		tmp_csa_settings = rcu_dereference(ifmsh->csa);
+		rcu_assign_pointer(ifmsh->csa, NULL);
+		kfree_rcu(tmp_csa_settings, rcu_head);
+		return ret;
+	}
+
+	ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
+
+	if (csa_action)
+		ieee80211_send_action_csa(sdata, csa_settings);
+
+	return 0;
+}
+
 static int mesh_fwd_csa_frame(struct ieee80211_sub_if_data *sdata,
 			       struct ieee80211_mgmt *mgmt, size_t len)
 {
@@ -942,6 +1039,7 @@ static int mesh_fwd_csa_frame(struct ieee80211_sub_if_data *sdata,
 	offset_ttl = (len < 42) ? 7 : 10;
 	*(pos + offset_ttl) -= 1;
 	*(pos + offset_ttl + 1) &= ~WLAN_EID_CHAN_SWITCH_PARAM_INITIATOR;
+	sdata->u.mesh.chsw_ttl = *(pos + offset_ttl);
 
 	memcpy(mgmt_fwd, mgmt, len);
 	eth_broadcast_addr(mgmt_fwd->da);