From 202a26dbc1d0a1cbb3f2ce9001df80eed5f6e27d Mon Sep 17 00:00:00 2001
From: Daniel Borkmann <borkmann@gnumaniacs.org>
Date: Fri, 3 Jun 2011 11:47:35 +0200
Subject: [PATCH] added emergency queue, so that packet can be queued up if a
 fblock is unavailable for a short period of time

---
 src/xt_engine.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 52 insertions(+), 6 deletions(-)

diff --git a/src/xt_engine.c b/src/xt_engine.c
index 9042a71..ecaa632 100644
--- a/src/xt_engine.c
+++ b/src/xt_engine.c
@@ -24,7 +24,12 @@ struct engine_iostats {
 	unsigned long long fblocks;
 } ____cacheline_aligned;
 
+struct engine_disc {
+	struct sk_buff_head ppe_rcv_emerg_queue;
+} ____cacheline_aligned;
+
 static struct engine_iostats __percpu *iostats;
+static struct engine_disc __percpu *emdiscs;
 
 extern struct proc_dir_entry *lana_proc_dir;
 static struct proc_dir_entry *engine_proc;
@@ -44,6 +49,18 @@ static inline void engine_add_bytes_stats(unsigned long bytes)
 	this_cpu_add(iostats->bytes, bytes);
 }
 
+static inline void engine_rcv_emerg_tail(struct sk_buff *skb)
+{
+	skb_queue_tail(&(this_cpu_ptr(emdiscs)->ppe_rcv_emerg_queue), skb);
+}
+
+static inline struct sk_buff *engine_rcv_emerg_test_reduce(void)
+{
+	return skb_dequeue(&(this_cpu_ptr(emdiscs)->ppe_rcv_emerg_queue));
+}
+
+/* TODO: handle emergency queue, or backlog */
+
 /* Main function, must be called in rcu_read_lock context */
 int process_packet(struct sk_buff *skb, enum path_type dir)
 {
@@ -82,10 +99,13 @@ static int engine_procfs(char *page, char **start, off_t offset,
 	get_online_cpus();
 	for_each_online_cpu(cpu) {
 		struct engine_iostats *iostats_cpu;
+		struct engine_disc *emdisc_cpu;
 		iostats_cpu = per_cpu_ptr(iostats, cpu);
-		len += sprintf(page + len, "CPU%u:\t%llu\t%llu\t%llu\n",
+		emdisc_cpu = per_cpu_ptr(emdiscs, cpu);
+		len += sprintf(page + len, "CPU%u:\t%llu\t%llu\t%llu\t%u\n",
 			       cpu, iostats_cpu->pkts, iostats_cpu->bytes,
-			       iostats_cpu->fblocks);
+			       iostats_cpu->fblocks,
+			       skb_queue_len(&emdisc_cpu->ppe_rcv_emerg_queue));
 	}
 	put_online_cpus();
 
@@ -109,21 +129,47 @@ int init_engine(void)
 		iostats_cpu->fblocks = 0;
 	}
 	put_online_cpus();
+
+	emdiscs = alloc_percpu(struct engine_disc);
+	if (!emdiscs)
+		goto err;
+	get_online_cpus();
+	for_each_online_cpu(cpu) {
+		struct engine_disc *emdisc_cpu;
+		emdisc_cpu = per_cpu_ptr(emdiscs, cpu);
+		skb_queue_head_init(&emdisc_cpu->ppe_rcv_emerg_queue);
+	}
+	put_online_cpus();
+
 	engine_proc = create_proc_read_entry("ppe", 0400, lana_proc_dir,
 					     engine_procfs, NULL);
-	if (!engine_proc) {
-		free_percpu(iostats);
-		return -ENOMEM;
-	}
+	if (!engine_proc)
+		goto err1;
 
 	return 0;
+err1:
+	free_percpu(emdiscs);
+err:
+	free_percpu(iostats);
+	return -ENOMEM;
 }
 EXPORT_SYMBOL_GPL(init_engine);
 
 void cleanup_engine(void)
 {
+	unsigned int cpu;
 	if (iostats)
 		free_percpu(iostats);
+	if (emdiscs) {
+		get_online_cpus();
+		for_each_online_cpu(cpu) {
+			struct engine_disc *emdisc_cpu;
+			emdisc_cpu = per_cpu_ptr(emdiscs, cpu);
+			skb_queue_purge(&emdisc_cpu->ppe_rcv_emerg_queue);
+		}
+		put_online_cpus();
+		free_percpu(emdiscs);
+	}
 	remove_proc_entry("ppe", lana_proc_dir);
 }
 EXPORT_SYMBOL_GPL(cleanup_engine);
-- 
2.11.4.GIT