{nl,cfg,mac}80211: implement dot11MeshHWMPconfirmationInterval

As defined in section 13.10.9.3 Case D (802.11-2012), this
control variable is used to limit the mesh STA to send only
one PREQ to a root mesh STA within this interval of time
(in TUs). The default value for this variable is set to
2000 TUs. However, for current implementation, the maximum
configurable of dot11MeshHWMPconfirmationInterval is
restricted by dot11MeshHWMPactivePathTimeout.

Signed-off-by: Chun-Yeow Yeoh <yeohchunyeow@gmail.com>
[line-break commit log]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/linux/nl80211.h

@@ -2192,6 +2192,10 @@ enum nl80211_mntr_flags {
  * @NL80211_MESHCONF_HWMP_ROOT_INTERVAL: The interval of time (in TUs) between
  *	proactive PREQs are transmitted.
  *
+ * @NL80211_MESHCONF_HWMP_CONFIRMATION_INTERVAL: The minimum interval of time
+ *	(in TUs) during which a mesh STA can send only one Action frame
+ *	containing a PREQ element for root path confirmation.
+ *
  * @__NL80211_MESHCONF_ATTR_AFTER_LAST: internal use
  */
 enum nl80211_meshconf_params {
@@ -2220,6 +2224,7 @@ enum nl80211_meshconf_params {
 	NL80211_MESHCONF_HT_OPMODE,
 	NL80211_MESHCONF_HWMP_PATH_TO_ROOT_TIMEOUT,
 	NL80211_MESHCONF_HWMP_ROOT_INTERVAL,
+	NL80211_MESHCONF_HWMP_CONFIRMATION_INTERVAL,
 
 	/* keep last */
 	__NL80211_MESHCONF_ATTR_AFTER_LAST,

include/net/cfg80211.h

@@ -849,6 +849,9 @@ struct bss_parameters {
  *
  * @dot11MeshHWMProotInterval: The interval of time (in TUs) between proactive
  *	PREQs are transmitted.
+ * @dot11MeshHWMPconfirmationInterval: The minimum interval of time (in TUs)
+ *	during which a mesh STA can send only one Action frame containing
+ *	a PREQ element for root path confirmation.
  */
 struct mesh_config {
 	u16 dot11MeshRetryTimeout;
@@ -875,6 +878,7 @@ struct mesh_config {
 	u16 ht_opmode;
 	u32 dot11MeshHWMPactivePathToRootTimeout;
 	u16 dot11MeshHWMProotInterval;
+	u16 dot11MeshHWMPconfirmationInterval;
 };
 
 /**

net/mac80211/cfg.c

@@ -1596,6 +1596,9 @@ static int ieee80211_update_mesh_config(struct wiphy *wiphy,
 	if (_chg_mesh_attr(NL80211_MESHCONF_HWMP_ROOT_INTERVAL, mask))
 		conf->dot11MeshHWMProotInterval =
 			nconf->dot11MeshHWMProotInterval;
+	if (_chg_mesh_attr(NL80211_MESHCONF_HWMP_CONFIRMATION_INTERVAL, mask))
+		conf->dot11MeshHWMPconfirmationInterval =
+			nconf->dot11MeshHWMPconfirmationInterval;
 	return 0;
 }
 

net/mac80211/debugfs_netdev.c

@@ -514,6 +514,8 @@ IEEE80211_IF_FILE(dot11MeshHWMPactivePathToRootTimeout,
 		  u.mesh.mshcfg.dot11MeshHWMPactivePathToRootTimeout, DEC);
 IEEE80211_IF_FILE(dot11MeshHWMProotInterval,
 		  u.mesh.mshcfg.dot11MeshHWMProotInterval, DEC);
+IEEE80211_IF_FILE(dot11MeshHWMPconfirmationInterval,
+		  u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval, DEC);
 #endif
 
 #define DEBUGFS_ADD_MODE(name, mode) \
@@ -617,6 +619,7 @@ static void add_mesh_config(struct ieee80211_sub_if_data *sdata)
 	MESHPARAMS_ADD(ht_opmode);
 	MESHPARAMS_ADD(dot11MeshHWMPactivePathToRootTimeout);
 	MESHPARAMS_ADD(dot11MeshHWMProotInterval);
+	MESHPARAMS_ADD(dot11MeshHWMPconfirmationInterval);
 #undef MESHPARAMS_ADD
 }
 #endif

net/mac80211/mesh.h

@@ -104,6 +104,7 @@ enum mesh_deferred_task_flags {
  * an mpath to a hash bucket on a path table.
  * @rann_snd_addr: the RANN sender address
  * @rann_metric: the aggregated path metric towards the root node
+ * @last_preq_to_root: Timestamp of last PREQ sent to root
  * @is_root: the destination station of this path is a root node
  * @is_gate: the destination station of this path is a mesh gate
  *
@@ -131,6 +132,7 @@ struct mesh_path {
 	spinlock_t state_lock;
 	u8 rann_snd_addr[ETH_ALEN];
 	u32 rann_metric;
+	unsigned long last_preq_to_root;
 	bool is_root;
 	bool is_gate;
 };

net/mac80211/mesh_hwmp.c

@@ -98,6 +98,8 @@ static inline u32 u16_field_get(u8 *preq_elem, int offset, bool ae)
 #define max_preq_retries(s) (s->u.mesh.mshcfg.dot11MeshHWMPmaxPREQretries)
 #define disc_timeout_jiff(s) \
 	msecs_to_jiffies(sdata->u.mesh.mshcfg.min_discovery_timeout)
+#define root_path_confirmation_jiffies(s) \
+	msecs_to_jiffies(sdata->u.mesh.mshcfg.dot11MeshHWMPconfirmationInterval)
 
 enum mpath_frame_type {
 	MPATH_PREQ = 0,
@@ -811,11 +813,14 @@ static void hwmp_rann_frame_process(struct ieee80211_sub_if_data *sdata,
 	}
 
 	if ((!(mpath->flags & (MESH_PATH_ACTIVE | MESH_PATH_RESOLVING)) ||
-	     time_after(jiffies, mpath->exp_time - 1*HZ)) &&
+	     (time_after(jiffies, mpath->last_preq_to_root +
+				  root_path_confirmation_jiffies(sdata)) ||
+	     time_before(jiffies, mpath->last_preq_to_root))) &&
 	     !(mpath->flags & MESH_PATH_FIXED)) {
 		mhwmp_dbg("%s time to refresh root mpath %pM", sdata->name,
 							       orig_addr);
 		mesh_queue_preq(mpath, PREQ_Q_F_START | PREQ_Q_F_REFRESH);
+		mpath->last_preq_to_root = jiffies;
 	}
 
 	if ((SN_LT(mpath->sn, orig_sn) || (mpath->sn == orig_sn &&

net/wireless/mesh.c

@@ -16,6 +16,7 @@
 #define MESH_RANN_INTERVAL      5000
 #define MESH_PATH_TO_ROOT_TIMEOUT      6000
 #define MESH_ROOT_INTERVAL     5000
+#define MESH_ROOT_CONFIRMATION_INTERVAL 2000
 
 /*
  * Minimum interval between two consecutive PREQs originated by the same
@@ -66,6 +67,7 @@ const struct mesh_config default_mesh_config = {
 	.ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED,
 	.dot11MeshHWMPactivePathToRootTimeout = MESH_PATH_TO_ROOT_TIMEOUT,
 	.dot11MeshHWMProotInterval = MESH_ROOT_INTERVAL,
+	.dot11MeshHWMPconfirmationInterval = MESH_ROOT_CONFIRMATION_INTERVAL,
 };
 
 const struct mesh_setup default_mesh_setup = {

net/wireless/nl80211.c

@@ -3473,7 +3473,9 @@ static int nl80211_get_mesh_config(struct sk_buff *skb,
 	    nla_put_u32(msg, NL80211_MESHCONF_HWMP_PATH_TO_ROOT_TIMEOUT,
 			cur_params.dot11MeshHWMPactivePathToRootTimeout) ||
 	    nla_put_u16(msg, NL80211_MESHCONF_HWMP_ROOT_INTERVAL,
-			cur_params.dot11MeshHWMProotInterval))
+			cur_params.dot11MeshHWMProotInterval) ||
+	    nla_put_u16(msg, NL80211_MESHCONF_HWMP_CONFIRMATION_INTERVAL,
+			cur_params.dot11MeshHWMPconfirmationInterval))
 		goto nla_put_failure;
 	nla_nest_end(msg, pinfoattr);
 	genlmsg_end(msg, hdr);
@@ -3511,6 +3513,7 @@ static const struct nla_policy nl80211_meshconf_params_policy[NL80211_MESHCONF_A
 	[NL80211_MESHCONF_HT_OPMODE] = { .type = NLA_U16 },
 	[NL80211_MESHCONF_HWMP_PATH_TO_ROOT_TIMEOUT] = { .type = NLA_U32 },
 	[NL80211_MESHCONF_HWMP_ROOT_INTERVAL] = { .type = NLA_U16 },
+	[NL80211_MESHCONF_HWMP_CONFIRMATION_INTERVAL] = { .type = NLA_U16 },
 };
 
 static const struct nla_policy
@@ -3625,6 +3628,10 @@ do {\
 	FILL_IN_MESH_PARAM_IF_SET(tb, cfg, dot11MeshHWMProotInterval,
 				  mask, NL80211_MESHCONF_HWMP_ROOT_INTERVAL,
 				  nla_get_u16);
+	FILL_IN_MESH_PARAM_IF_SET(tb, cfg,
+				  dot11MeshHWMPconfirmationInterval, mask,
+				  NL80211_MESHCONF_HWMP_CONFIRMATION_INTERVAL,
+				  nla_get_u16);
 	if (mask_out)
 		*mask_out = mask;