Commit 8f2535b9 authored by Chun-Yeow Yeoh's avatar Chun-Yeow Yeoh Committed by Johannes Berg
Browse files

mac80211: process the CSA frame for mesh accordingly 



Process the CSA frame according to the procedures define in IEEE Std
802.11-2012 section 10.9.8.4.3 as follow:
* The mesh channel switch parameters element (MCSP) must be availabe.
* If the MCSP's TTL is 1, drop the frame but still process the CSA.
* If the MCSP's precedence value is less than or equal to the current
  precedence value, drop the frame and do not process the CSA.
* The CSA frame is forwarded after TTL is decremented by 1 and the
  initiator field is set to 0. Transmit restrict field and others
  are maintained as is.
* No beacon or probe response frame are handled here.

Also, introduce the debug message used for mesh CSA purpose.

Signed-off-by: default avatarChun-Yeow Yeoh <yeohchunyeow@cozybit.com>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent c0f17eb9

include/linux/ieee80211.h

+20 −0
Original line number Diff line number Diff line
@@ -696,6 +696,18 @@ struct ieee80211_sec_chan_offs_ie { 
	u8 sec_chan_offs;

} __packed;



/**

 * struct ieee80211_mesh_chansw_params_ie - mesh channel switch parameters IE

 *

 * This structure represents the "Mesh Channel Switch Paramters element"

 */

struct ieee80211_mesh_chansw_params_ie {

	u8 mesh_ttl;

	u8 mesh_flags;

	__le16 mesh_reason;

	__le16 mesh_pre_value;

} __packed;



/**

 * struct ieee80211_wide_bw_chansw_ie - wide bandwidth channel switch IE

 */
@@ -750,6 +762,14 @@ enum mesh_config_capab_flags { 
	IEEE80211_MESHCONF_CAPAB_POWER_SAVE_LEVEL	= 0x40,

};



/**

 * mesh channel switch parameters element's flag indicator

 *

 */

#define WLAN_EID_CHAN_SWITCH_PARAM_TX_RESTRICT BIT(0)

#define WLAN_EID_CHAN_SWITCH_PARAM_INITIATOR BIT(1)

#define WLAN_EID_CHAN_SWITCH_PARAM_REASON BIT(2)



/**

 * struct ieee80211_rann_ie

 *

net/mac80211/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -259,6 +259,17 @@ config MAC80211_MESH_SYNC_DEBUG 


	  Do not select this option.



config MAC80211_MESH_CSA_DEBUG

	bool "Verbose mesh channel switch debugging"

	depends on MAC80211_DEBUG_MENU

	depends on MAC80211_MESH

	---help---

	  Selecting this option causes mac80211 to print out very verbose mesh

	  channel switch debugging messages (when mac80211 is taking part in a

	  mesh network).



	  Do not select this option.



config MAC80211_MESH_PS_DEBUG

	bool "Verbose mesh powersave debugging"

	depends on MAC80211_DEBUG_MENU

net/mac80211/debug.h

+10 −0
Original line number Diff line number Diff line
@@ -44,6 +44,12 @@ 
#define MAC80211_MESH_SYNC_DEBUG 0

#endif



#ifdef CONFIG_MAC80211_MESH_CSA_DEBUG

#define MAC80211_MESH_CSA_DEBUG 1

#else

#define MAC80211_MESH_CSA_DEBUG 0

#endif



#ifdef CONFIG_MAC80211_MESH_PS_DEBUG

#define MAC80211_MESH_PS_DEBUG 1

#else
@@ -157,6 +163,10 @@ do { \ 
	_sdata_dbg(MAC80211_MESH_SYNC_DEBUG,				\

		   sdata, fmt, ##__VA_ARGS__)



#define mcsa_dbg(sdata, fmt, ...)					\

	_sdata_dbg(MAC80211_MESH_CSA_DEBUG,				\

		   sdata, fmt, ##__VA_ARGS__)



#define mps_dbg(sdata, fmt, ...)					\

	_sdata_dbg(MAC80211_MESH_PS_DEBUG,				\

		   sdata, fmt, ##__VA_ARGS__)

net/mac80211/ieee80211_i.h

+4 −0
Original line number Diff line number Diff line
@@ -603,6 +603,9 @@ struct ieee80211_if_mesh { 
	int ps_peers_light_sleep;

	int ps_peers_deep_sleep;

	struct ps_data ps;

	/* Channel Switching Support */

	bool chsw_init;

	u16 pre_value;

};



#ifdef CONFIG_MAC80211_MESH
@@ -1252,6 +1255,7 @@ struct ieee802_11_elems { 
	const struct ieee80211_timeout_interval_ie *timeout_int;

	const u8 *opmode_notif;

	const struct ieee80211_sec_chan_offs_ie *sec_chan_offs;

	const struct ieee80211_mesh_chansw_params_ie *mesh_chansw_params_ie;



	/* length of them, respectively */

	u8 ssid_len;

net/mac80211/mesh.c

+80 −3
Original line number Diff line number Diff line
@@ -920,6 +920,82 @@ static void ieee80211_mesh_rx_bcn_presp(struct ieee80211_sub_if_data *sdata, 
			stype, mgmt, &elems, rx_status);

}



static int mesh_fwd_csa_frame(struct ieee80211_sub_if_data *sdata,

			       struct ieee80211_mgmt *mgmt, size_t len)

{

	struct ieee80211_mgmt *mgmt_fwd;

	struct sk_buff *skb;

	struct ieee80211_local *local = sdata->local;

	u8 *pos = mgmt->u.action.u.chan_switch.variable;

	size_t offset_ttl;



	skb = dev_alloc_skb(local->tx_headroom + len);

	if (!skb)

		return -ENOMEM;

	skb_reserve(skb, local->tx_headroom);

	mgmt_fwd = (struct ieee80211_mgmt *) skb_put(skb, len);



	/* offset_ttl is based on whether the secondary channel

	 * offset is available or not. Substract 1 from the mesh TTL

	 * and disable the initiator flag before forwarding.

	 */

	offset_ttl = (len < 42) ? 7 : 10;

	*(pos + offset_ttl) -= 1;

	*(pos + offset_ttl + 1) &= ~WLAN_EID_CHAN_SWITCH_PARAM_INITIATOR;



	memcpy(mgmt_fwd, mgmt, len);

	eth_broadcast_addr(mgmt_fwd->da);

	memcpy(mgmt_fwd->sa, sdata->vif.addr, ETH_ALEN);

	memcpy(mgmt_fwd->bssid, sdata->vif.addr, ETH_ALEN);



	ieee80211_tx_skb(sdata, skb);

	return 0;

}



static void mesh_rx_csa_frame(struct ieee80211_sub_if_data *sdata,

			      struct ieee80211_mgmt *mgmt, size_t len)

{

	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;

	struct ieee802_11_elems elems;

	u16 pre_value;

	bool block_tx, fwd_csa = true;

	size_t baselen;

	u8 *pos, ttl;



	if (mgmt->u.action.u.measurement.action_code !=

	    WLAN_ACTION_SPCT_CHL_SWITCH)

		return;



	pos = mgmt->u.action.u.chan_switch.variable;

	baselen = offsetof(struct ieee80211_mgmt,

			   u.action.u.chan_switch.variable);

	ieee802_11_parse_elems(pos, len - baselen, false, &elems);



	ttl = elems.mesh_chansw_params_ie->mesh_ttl;

	if (!--ttl)

		fwd_csa = false;



	pre_value = le16_to_cpu(elems.mesh_chansw_params_ie->mesh_pre_value);

	if (ifmsh->pre_value >= pre_value)

		return;



	ifmsh->pre_value = pre_value;



	/* forward or re-broadcast the CSA frame */

	if (fwd_csa) {

		if (mesh_fwd_csa_frame(sdata, mgmt, len) < 0)

			mcsa_dbg(sdata, "Failed to forward the CSA frame");

	}



	/* block the Tx only after forwarding the CSA frame if required */

	block_tx = elems.mesh_chansw_params_ie->mesh_flags &

		   WLAN_EID_CHAN_SWITCH_PARAM_TX_RESTRICT;

	if (block_tx)

		ieee80211_stop_queues_by_reason(&sdata->local->hw,

				IEEE80211_MAX_QUEUE_MAP,

				IEEE80211_QUEUE_STOP_REASON_CSA);

}



static void ieee80211_mesh_rx_mgmt_action(struct ieee80211_sub_if_data *sdata,

					  struct ieee80211_mgmt *mgmt,

					  size_t len,
@@ -939,6 +1015,9 @@ static void ieee80211_mesh_rx_mgmt_action(struct ieee80211_sub_if_data *sdata, 
		if (mesh_action_is_path_sel(mgmt))

			mesh_rx_path_sel_frame(sdata, mgmt, len);

		break;

	case WLAN_CATEGORY_SPECTRUM_MGMT:

		mesh_rx_csa_frame(sdata, mgmt, len);

		break;

	}

}
@@ -1056,13 +1135,11 @@ void ieee80211_mesh_init_sdata(struct ieee80211_sub_if_data *sdata) 
		    (unsigned long) sdata);



	ifmsh->accepting_plinks = true;

	ifmsh->preq_id = 0;

	ifmsh->sn = 0;

	ifmsh->num_gates = 0;

	atomic_set(&ifmsh->mpaths, 0);

	mesh_rmc_init(sdata);

	ifmsh->last_preq = jiffies;

	ifmsh->next_perr = jiffies;

	ifmsh->chsw_init = false;

	/* Allocate all mesh structures when creating the first mesh interface. */

	if (!mesh_allocated)

		ieee80211s_init();

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