igmp: Allow mininum interval specification for igmp timers.

Commit Message

Christoph Lameter (Ampere) Sept. 22, 2010, 6:59 p.m. UTC

None

Patch

Index: linux-2.6/net/ipv4/igmp.c
===================================================================
--- linux-2.6.orig/net/ipv4/igmp.c	2010-09-22 11:15:19.000000000 -0500
+++ linux-2.6/net/ipv4/igmp.c	2010-09-22 12:50:32.000000000 -0500
@@ -116,10 +116,17 @@ 
 #define IGMP_V2_Router_Present_Timeout		(400*HZ)
 #define IGMP_Unsolicited_Report_Interval	(10*HZ)
 #define IGMP_Query_Response_Interval		(10*HZ)
-#define IGMP_Unsolicited_Report_Count		2

+/* Parameters not specified in igmp rfc. */
+
+/* Mininum ticks to have a meaningful notion of delay */
+#define IGMP_Mininum_Delay			(2)
+
+/* Control of unsolilcited reports (after join) */

+#define IGMP_Unsolicited_Report_Count		2
 #define IGMP_Initial_Report_Delay		(1)
+#define IGMP_Unsolicited_Report_Min_Delay	(HZ/25)

 /* IGMP_Initial_Report_Delay is not from IGMP specs!
  * IGMP specs require to report membership immediately after
@@ -174,22 +181,30 @@  static __inline__ void igmp_stop_timer(s
 	spin_unlock_bh(&im->lock);
 }

-/* It must be called with locked im->lock */
-static void igmp_start_timer(struct ip_mc_list *im, int max_delay)
+static inline unsigned long jiffies_rand_delay(int min_delay, int max_delay)
 {
-	int tv = net_random() % max_delay;
+	int d = min_delay;
+
+	if (min_delay < max_delay)
+		d += net_random() % (max_delay - min_delay);

+	return jiffies + d;
+}
+
+/* It must be called with locked im->lock */
+static void igmp_start_timer(struct ip_mc_list *im, int min_delay, int max_delay)
+{
 	im->tm_running = 1;
-	if (!mod_timer(&im->timer, jiffies+tv+2))
+	if (!mod_timer(&im->timer, jiffies_rand_delay(min_delay, max_delay)))
 		atomic_inc(&im->refcnt);
 }

 static void igmp_gq_start_timer(struct in_device *in_dev)
 {
-	int tv = net_random() % in_dev->mr_maxdelay;
-
 	in_dev->mr_gq_running = 1;
-	if (!mod_timer(&in_dev->mr_gq_timer, jiffies+tv+2))
+	if (!mod_timer(&in_dev->mr_gq_timer,
+			jiffies_rand_delay(IGMP_Mininum_Delay,
+					in_dev->mr_maxdelay)))
 		in_dev_hold(in_dev);
 }

@@ -201,7 +216,7 @@  static void igmp_ifc_start_timer(struct
 		in_dev_hold(in_dev);
 }

-static void igmp_mod_timer(struct ip_mc_list *im, int max_delay)
+static void igmp_mod_timer(struct ip_mc_list *im, int min_delay, int max_delay)
 {
 	spin_lock_bh(&im->lock);
 	im->unsolicit_count = 0;
@@ -214,7 +229,7 @@  static void igmp_mod_timer(struct ip_mc_
 		}
 		atomic_dec(&im->refcnt);
 	}
-	igmp_start_timer(im, max_delay);
+	igmp_start_timer(im, min_delay, max_delay);
 	spin_unlock_bh(&im->lock);
 }

@@ -733,7 +748,8 @@  static void igmp_timer_expire(unsigned l

 	if (im->unsolicit_count) {
 		im->unsolicit_count--;
-		igmp_start_timer(im, IGMP_Unsolicited_Report_Interval);
+		igmp_start_timer(im, IGMP_Unsolicited_Report_Min_Delay,
+				IGMP_Unsolicited_Report_Interval);
 	}
 	im->reporter = 1;
 	spin_unlock(&im->lock);
@@ -911,7 +927,7 @@  static void igmp_heard_query(struct in_d
 			igmp_marksources(im, ntohs(ih3->nsrcs), ih3->srcs);
 		spin_unlock_bh(&im->lock);
 		if (changed)
-			igmp_mod_timer(im, max_delay);
+			igmp_mod_timer(im, IGMP_Mininum_Delay, max_delay);
 	}
 	read_unlock(&in_dev->mc_list_lock);
 }
@@ -1169,7 +1185,7 @@  static void igmp_group_added(struct ip_m
 		return;
 	if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev)) {
 		spin_lock_bh(&im->lock);
-		igmp_start_timer(im, IGMP_Initial_Report_Delay);
+		igmp_start_timer(im, IGMP_Mininum_Delay, IGMP_Initial_Report_Delay);
 		spin_unlock_bh(&im->lock);
 		return;
 	}
@@ -1258,7 +1274,8 @@  void ip_mc_rejoin_group(struct ip_mc_lis
 		return;

 	if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev)) {
-		igmp_mod_timer(im, IGMP_Initial_Report_Delay);
+		igmp_mod_timer(im, IGMP_Mininum_Delay,
+					IGMP_Initial_Report_Delay);
 		return;
 	}
 	/* else, v3 */