svn commit: r246497 - head/sys/net80211

[Monthadar Al Jaberi]

Author: monthadar
Date: Thu Feb  7 21:12:55 2013
New Revision: 246497
URL: http://svnweb.freebsd.org/changeset/base/246497

Log:
  Stop a mesh STA from flooding with peer frames.
  
  This problem happens when using ACL policy to filter mesh STA
  but two nodes have different policy. Then one of them will try to
  peer all the time. This can also help if for any reason one of the
  peering mesh STA have problems sending/receiving peer frames.
  
  * Modified struct ieee80211_node to include two new fields:
      + struct callout ni_mlhtimer /* link mesh backoff timer */
      + uint8_t ni_mlhcnt /* link mesh holding counter */
  * Added two new sysctl (check sysctl -d for more info):
      + net.wlan.mesh.backofftimeout=5000
      + net.wlan.mesh.maxholding=2;
  * When receiving a beacon and we are in IEEE80211_NODE_MESH_IDLE
    check if ni_mlhcnt >= ieee80211_mesh_maxholding, if so do not do anything;
  * In mesh_peer_timeout_cb when transitioning from IEEE80211_NODE_MESH_HOLDING
    to IEEE80211_NODE_MESH_IDLE increment ni_mlhcnt, and eventually start
    ieee80211_mesh_backofftimeout;
  
  Approved by:	adrian (mentor)

Modified:
  head/sys/net80211/ieee80211_mesh.c
  head/sys/net80211/ieee80211_node.h

Modified: head/sys/net80211/ieee80211_mesh.c
==============================================================================
--- head/sys/net80211/ieee80211_mesh.c	Thu Feb  7 19:09:10 2013	(r246496)
+++ head/sys/net80211/ieee80211_mesh.c	Thu Feb  7 21:12:55 2013	(r246497)
@@ -111,10 +111,20 @@ static int ieee80211_mesh_confirmtimeout
 SYSCTL_PROC(_net_wlan_mesh, OID_AUTO, confirmtimeout, CTLTYPE_INT | CTLFLAG_RW,
     &ieee80211_mesh_confirmtimeout, 0, ieee80211_sysctl_msecs_ticks, "I",
     "Confirm state timeout (msec)");
+static int ieee80211_mesh_backofftimeout = -1;
+SYSCTL_PROC(_net_wlan_mesh, OID_AUTO, backofftimeout, CTLTYPE_INT | CTLFLAG_RW,
+    &ieee80211_mesh_backofftimeout, 0, ieee80211_sysctl_msecs_ticks, "I",
+    "Backoff timeout (msec). This is to throutles peering forever when "
+    "not receving answer or is rejected by a neighbor");
 static int ieee80211_mesh_maxretries = 2;
 SYSCTL_INT(_net_wlan_mesh, OID_AUTO, maxretries, CTLTYPE_INT | CTLFLAG_RW,
     &ieee80211_mesh_maxretries, 0,
     "Maximum retries during peer link establishment");
+static int ieee80211_mesh_maxholding = 2;
+SYSCTL_INT(_net_wlan_mesh, OID_AUTO, maxholding, CTLTYPE_INT | CTLFLAG_RW,
+    &ieee80211_mesh_maxholding, 0,
+    "Maximum times we are allowed to transition to HOLDING state before "
+    "backinoff during peer link establishment");
 
 static const uint8_t broadcastaddr[IEEE80211_ADDR_LEN] =
 	{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
@@ -500,6 +510,7 @@ ieee80211_mesh_init(void)
 	ieee80211_mesh_retrytimeout = msecs_to_ticks(40);
 	ieee80211_mesh_holdingtimeout = msecs_to_ticks(40);
 	ieee80211_mesh_confirmtimeout = msecs_to_ticks(40);
+	ieee80211_mesh_backofftimeout = msecs_to_ticks(5000);
 
 	/*
 	 * Register action frame handlers.
@@ -1696,7 +1707,6 @@ mesh_recv_mgmt(struct ieee80211_node *ni
 		}
 		/*
 		 * Automatically peer with discovered nodes if possible.
-		 * XXX backoff on repeated failure
 		 */
 		if (ni != vap->iv_bss &&
 		    (ms->ms_flags & IEEE80211_MESHFLAGS_AP)) {
@@ -1705,6 +1715,10 @@ mesh_recv_mgmt(struct ieee80211_node *ni
 			{
 				uint16_t args[1];
 
+				/* Wait for backoff callout to reset counter */
+				if (ni->ni_mlhcnt >= ieee80211_mesh_maxholding)
+					return;
+
 				ni->ni_mlpid = mesh_generateid(vap);
 				if (ni->ni_mlpid == 0)
 					return;
@@ -2578,6 +2592,15 @@ mesh_peer_timeout_stop(struct ieee80211_
 	callout_drain(&ni->ni_mltimer);
 }
 
+static void
+mesh_peer_backoff_cb(void *arg)
+{
+	struct ieee80211_node *ni = (struct ieee80211_node *)arg;
+
+	/* After backoff timeout, try to peer automatically again. */
+	ni->ni_mlhcnt = 0;
+}
+
 /*
  * Mesh Peer Link Management FSM timeout handling.
  */
@@ -2625,6 +2648,11 @@ mesh_peer_timeout_cb(void *arg)
 		mesh_peer_timeout_setup(ni);
 		break;
 	case IEEE80211_NODE_MESH_HOLDING:
+		ni->ni_mlhcnt++;
+		if (ni->ni_mlhcnt >= ieee80211_mesh_maxholding)
+			callout_reset(&ni->ni_mlhtimer,
+			    ieee80211_mesh_backofftimeout,
+			    mesh_peer_backoff_cb, ni);
 		mesh_linkchange(ni, IEEE80211_NODE_MESH_IDLE);
 		break;
 	}
@@ -2889,6 +2917,7 @@ ieee80211_mesh_node_init(struct ieee8021
 {
 	ni->ni_flags |= IEEE80211_NODE_QOS;
 	callout_init(&ni->ni_mltimer, CALLOUT_MPSAFE);
+	callout_init(&ni->ni_mlhtimer, CALLOUT_MPSAFE);
 }
 
 /*
@@ -2901,6 +2930,7 @@ ieee80211_mesh_node_cleanup(struct ieee8
 	struct ieee80211_mesh_state *ms = vap->iv_mesh;
 
 	callout_drain(&ni->ni_mltimer);
+	callout_drain(&ni->ni_mlhtimer);
 	/* NB: short-circuit callbacks after mesh_vdetach */
 	if (vap->iv_mesh != NULL)
 		ms->ms_ppath->mpp_peerdown(ni);

Modified: head/sys/net80211/ieee80211_node.h
==============================================================================
--- head/sys/net80211/ieee80211_node.h	Thu Feb  7 19:09:10 2013	(r246496)
+++ head/sys/net80211/ieee80211_node.h	Thu Feb  7 21:12:55 2013	(r246497)
@@ -204,6 +204,8 @@ struct ieee80211_node {
 	struct callout		ni_mltimer;	/* link mesh timer */
 	uint8_t			ni_mlrcnt;	/* link mesh retry counter */
 	uint8_t			ni_mltval;	/* link mesh timer value */
+	struct callout		ni_mlhtimer;	/* link mesh backoff timer */
+	uint8_t			ni_mlhcnt;	/* link mesh holding counter */
 
 	/* 11n state */
 	uint16_t		ni_htcap;	/* HT capabilities */