--- linux/net/core/dev.c.orig	Thu Sep  7 11:32:01 2000
+++ linux/net/core/dev.c	Tue Sep 12 20:02:20 2000
@@ -97,6 +97,9 @@
 extern int plip_init(void);
 #endif
 
+/*
+#define RAND_LIE 1
+*/
 NET_PROFILE_DEFINE(dev_queue_xmit)
 NET_PROFILE_DEFINE(softnet_process)
 
@@ -133,6 +136,11 @@
 static struct packet_type *ptype_base[16];		/* 16 way hashed list */
 static struct packet_type *ptype_all = NULL;		/* Taps */
 
+#ifdef offline_sample
+static void sample_queue(unsigned long dummy);
+static struct timer_list samp_timer = { { NULL, NULL }, 0, 0, &sample_queue };
+#endif
+
 /*
  *	Our notifier list
  */
@@ -951,12 +959,25 @@
   =======================================================================*/
 
 int netdev_max_backlog = 300;
+/* these numbers are selected based on intuition and some
+experimentatiom, if you have more scientific way of doing this
+please go ahead and fix things
+*/
+int no_cong_thresh=10;
+int no_cong=20;
+int lo_cong=100;
+int mod_cong=290;
+
+
 
 struct netif_rx_stats netdev_rx_stat[NR_CPUS];
 
 
 #ifdef CONFIG_NET_HW_FLOWCONTROL
+/*
 static atomic_t netdev_dropping = ATOMIC_INIT(0);
+*/
+atomic_t netdev_dropping = ATOMIC_INIT(0);
 static unsigned long netdev_fc_mask = 1;
 unsigned long netdev_fc_xoff = 0;
 spinlock_t netdev_fc_lock = SPIN_LOCK_UNLOCKED;
@@ -1014,6 +1035,56 @@
 }
 #endif
 
+static void get_sample_stats(int cpu)
+{
+#ifdef RAND_LIE
+	unsigned long rd;
+	int rq;
+#endif
+	int blog=softnet_data[cpu].input_pkt_queue.qlen;
+	int avg_blog=softnet_data[cpu].avg_blog;
+
+	avg_blog=(avg_blog >> 1)+ (blog>>1);
+
+	if (avg_blog > mod_cong) {
+/*  above moderate congestion levels */
+		softnet_data[cpu].cng_level= BLG_CNG_HIGH;
+#ifdef RAND_LIE
+		rd=net_random();
+		rq=rd% netdev_max_backlog;
+		if (rq < avg_blog) /* unlucky bastard */
+			softnet_data[cpu].cng_level=BLG_CNG_DROP;
+#endif
+	} else if (avg_blog > lo_cong) {
+		softnet_data[cpu].cng_level= BLG_CNG_MOD;
+#ifdef RAND_LIE
+		rd=net_random();
+		rq=rd% netdev_max_backlog;
+			if (rq < avg_blog) /* unlucky bastard */
+				softnet_data[cpu].cng_level=BLG_CNG_HIGH;
+#endif
+	} else if (avg_blog > no_cong) 
+		softnet_data[cpu].cng_level= BLG_CNG_LOW;
+	else  /* no congestion */
+		softnet_data[cpu].cng_level=BLG_CNG_NONE;
+
+	softnet_data[cpu].avg_blog=avg_blog;
+
+}
+
+#ifdef offline_samp
+static void sample_queue(unsigned long dummy)
+{
+/* 10 ms 0r 1ms -- i dont care -- JHS */
+	int next_tick=1;
+	int cpu=smp_processor_id();
+	get_sample_stats(cpu);
+	next_tick+=jiffies;
+	mod_timer(&samp_timer, next_tick);
+}
+#endif
+
+
 /**
  *	netif_rx	-	post buffer to the network code
  *	@skb: buffer to post
@@ -1022,9 +1093,18 @@
  *	the upper (protocol) levels to process.  It always succeeds. The buffer
  *	may be dropped during processing for congestion control or by the 
  *	protocol layers.
+ *      
+ *	return values:
+ *	BLG_CNG_NONE	(no congestion)           
+ *	BLG_CNG_LOW     (low congestion) 
+ *	BLG_CNG_MOD     (moderate congestion)
+ *	BLG_CNG_HIGH    (high congestion) 
+ *	BLG_CNG_DROP    (packet was dropped)
+ *      
+ *      
  */
 
-void netif_rx(struct sk_buff *skb)
+int netif_rx(struct sk_buff *skb)
 {
 	int this_cpu = smp_processor_id();
 	struct softnet_data *queue;
@@ -1043,6 +1123,7 @@
 	netdev_rx_stat[this_cpu].total++;
 	if (queue->input_pkt_queue.qlen <= netdev_max_backlog) {
 		if (queue->input_pkt_queue.qlen) {
+
 			if (queue->throttle)
 				goto drop;
 
@@ -1054,11 +1135,16 @@
 			__skb_queue_tail(&queue->input_pkt_queue,skb);
 			__cpu_raise_softirq(this_cpu, NET_RX_SOFTIRQ);
 			local_irq_restore(flags);
-			return;
+#ifndef offline_samp
+			get_sample_stats(this_cpu);
+#endif
+			return softnet_data[this_cpu].cng_level;
+
 		}
 
 		if (queue->throttle) {
 			queue->throttle = 0;
+
 #ifdef CONFIG_NET_HW_FLOWCONTROL
 			if (atomic_dec_and_test(&netdev_dropping))
 				netdev_wakeup();
@@ -1080,6 +1166,8 @@
 	local_irq_restore(flags);
 
 	kfree_skb(skb);
+	return BLG_CNG_DROP;
+
 }
 
 /* Deliver skb to an old protocol, which is not threaded well
@@ -1292,12 +1380,28 @@
 
 		if (bugdet-- < 0 || jiffies - start_time > 1)
 			goto softnet_break;
+
+/* 
+*/
+#ifdef CONFIG_NET_HW_FLOWCONTROL
+	if (queue->throttle && queue->input_pkt_queue.qlen < no_cong_thresh ) {
+		if (atomic_dec_and_test(&netdev_dropping))  {
+			queue->throttle = 0;
+			netdev_wakeup();
+			goto softnet_break;
+		}
+
+	}
+#endif
+
+
 	}
 	br_read_unlock(BR_NETPROTO_LOCK);
 
 	local_irq_disable();
 	if (queue->throttle) {
 		queue->throttle = 0;
+
 #ifdef CONFIG_NET_HW_FLOWCONTROL
 		if (atomic_dec_and_test(&netdev_dropping))
 			netdev_wakeup();
@@ -2418,6 +2522,7 @@
 int __init net_dev_init(void)
 {
 	struct net_device *dev, **dp;
+
 	int i;
 
 #ifdef CONFIG_NET_SCHED
@@ -2434,6 +2539,8 @@
 		queue = &softnet_data[i];
 		skb_queue_head_init(&queue->input_pkt_queue);
 		queue->throttle = 0;
+		queue->cng_level = 0;
+		queue->avg_blog = 10; /* arbitrary non-zero */
 		queue->completion_queue = NULL;
 	}
 	
@@ -2442,6 +2549,12 @@
 	NET_PROFILE_REGISTER(dev_queue_xmit);
 	NET_PROFILE_REGISTER(softnet_process);
 #endif
+
+#ifdef offline_samp
+	samp_timer.expires=jiffies+(10 * HZ);
+	add_timer(&samp_timer);
+#endif
+
 	/*
 	 *	Add the devices.
 	 *	If the call to dev->init fails, the dev is removed
@@ -2499,6 +2612,7 @@
 #ifdef CONFIG_PROC_FS
 	proc_net_create("dev", 0, dev_get_info);
 	create_proc_read_entry("net/softnet_stat", 0, 0, dev_proc_stats, NULL);
+
 #ifdef WIRELESS_EXT
 	proc_net_create("wireless", 0, dev_get_wireless_info);
 #endif	/* WIRELESS_EXT */
--- linux/include/linux/netdevice.h.orig	Fri Sep  8 15:53:53 2000
+++ linux/include/linux/netdevice.h	Tue Sep 12 20:01:25 2000
@@ -47,6 +47,13 @@
 					   (TC use only - dev_queue_xmit
 					   returns this as NET_XMIT_SUCCESS) */
 
+/* Backlog congestion levels */
+#define BLG_CNG_NONE		1   /* keep 'em coming, baby */
+#define BLG_CNG_LOW		2   /* storm alert, just in case */
+#define BLG_CNG_MOD		3   /* Storm on its way! */
+#define BLG_CNG_HIGH		5   /* The Tsunami is here, boys and girls */
+#define BLG_CNG_DROP		-1  /* too late,mon ami! packet dropped */
+
 #define net_xmit_errno(e)	((e) != NET_XMIT_CN ? -ENOBUFS : 0)
 
 #endif
@@ -440,6 +447,8 @@
 struct softnet_data
 {
 	int			throttle;
+	int			cng_level;
+	int			avg_blog;
 	struct sk_buff_head	input_pkt_queue;
 	struct net_device	*output_queue;
 	struct sk_buff		*completion_queue;
@@ -526,7 +535,7 @@
 
 extern void		net_call_rx_atomic(void (*fn)(void));
 #define HAVE_NETIF_RX 1
-extern void		netif_rx(struct sk_buff *skb);
+extern int		netif_rx(struct sk_buff *skb);
 extern int		dev_ioctl(unsigned int cmd, void *);
 extern int		dev_change_flags(struct net_device *, unsigned);
 extern void		dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev);
@@ -628,6 +637,7 @@
 extern void		netdev_unregister_fc(int bit);
 extern int		netdev_max_backlog;
 extern unsigned long	netdev_fc_xoff;
+extern atomic_t netdev_dropping;
 extern int		netdev_set_master(struct net_device *dev, struct net_device *master);
 #ifdef CONFIG_NET_FASTROUTE
 extern int		netdev_fastroute;
--- /usr/src/linux/net/netsyms.c	2000/09/16 23:00:33	1.1
+++ /usr/src/linux/net/netsyms.c	2000/09/16 23:01:28
@@ -490,6 +490,7 @@
 EXPORT_SYMBOL(dev_ioctl);
 EXPORT_SYMBOL(dev_queue_xmit);
 #ifdef CONFIG_NET_HW_FLOWCONTROL
+EXPORT_SYMBOL(netdev_dropping);
 EXPORT_SYMBOL(netdev_register_fc);
 EXPORT_SYMBOL(netdev_unregister_fc);
 EXPORT_SYMBOL(netdev_fc_xoff);