Initial file dump from open source releaseHEADmaster

1 files changed, 292 insertions, 0 deletions

diff --git a/net/netfilter/ipvs/ip_vs_sh.c b/net/netfilter/ipvs/ip_vs_sh.c
new file mode 100644
index 00000000..a65edfe4
--- /dev/null
+++ b/net/netfilter/ipvs/ip_vs_sh.c
@@ -0,0 +1,292 @@
+/*
+ * IPVS:        Source Hashing scheduling module
+ *
+ * Authors:     Wensong Zhang <wensong@gnuchina.org>
+ *
+ *              This program is free software; you can redistribute it and/or
+ *              modify it under the terms of the GNU General Public License
+ *              as published by the Free Software Foundation; either version
+ *              2 of the License, or (at your option) any later version.
+ *
+ * Changes:
+ *
+ */
+
+/*
+ * The sh algorithm is to select server by the hash key of source IP
+ * address. The pseudo code is as follows:
+ *
+ *       n <- servernode[src_ip];
+ *       if (n is dead) OR
+ *          (n is overloaded) or (n.weight <= 0) then
+ *                 return NULL;
+ *
+ *       return n;
+ *
+ * Notes that servernode is a 256-bucket hash table that maps the hash
+ * index derived from packet source IP address to the current server
+ * array. If the sh scheduler is used in cache cluster, it is good to
+ * combine it with cache_bypass feature. When the statically assigned
+ * server is dead or overloaded, the load balancer can bypass the cache
+ * server and send requests to the original server directly.
+ *
+ * The weight destination attribute can be used to control the
+ * distribution of connections to the destinations in servernode. The
+ * greater the weight, the more connections the destination
+ * will receive.
+ *
+ */
+
+#define KMSG_COMPONENT "IPVS"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/ip.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+
+#include <net/ip_vs.h>
+
+
+/*
+ *      IPVS SH bucket
+ */
+struct ip_vs_sh_bucket {
+	struct ip_vs_dest __rcu	*dest;	/* real server (cache) */
+};
+
+/*
+ *     for IPVS SH entry hash table
+ */
+#ifndef CONFIG_IP_VS_SH_TAB_BITS
+#define CONFIG_IP_VS_SH_TAB_BITS        8
+#endif
+#define IP_VS_SH_TAB_BITS               CONFIG_IP_VS_SH_TAB_BITS
+#define IP_VS_SH_TAB_SIZE               (1 << IP_VS_SH_TAB_BITS)
+#define IP_VS_SH_TAB_MASK               (IP_VS_SH_TAB_SIZE - 1)
+
+struct ip_vs_sh_state {
+	struct rcu_head			rcu_head;
+	struct ip_vs_sh_bucket		buckets[IP_VS_SH_TAB_SIZE];
+};
+
+/*
+ *	Returns hash value for IPVS SH entry
+ */
+static inline unsigned int ip_vs_sh_hashkey(int af, const union nf_inet_addr *addr)
+{
+	__be32 addr_fold = addr->ip;
+
+#ifdef CONFIG_IP_VS_IPV6
+	if (af == AF_INET6)
+		addr_fold = addr->ip6[0]^addr->ip6[1]^
+			    addr->ip6[2]^addr->ip6[3];
+#endif
+	return (ntohl(addr_fold)*2654435761UL) & IP_VS_SH_TAB_MASK;
+}
+
+
+/*
+ *      Get ip_vs_dest associated with supplied parameters.
+ */
+static inline struct ip_vs_dest *
+ip_vs_sh_get(int af, struct ip_vs_sh_state *s, const union nf_inet_addr *addr)
+{
+	return rcu_dereference(s->buckets[ip_vs_sh_hashkey(af, addr)].dest);
+}
+
+
+/*
+ *      Assign all the hash buckets of the specified table with the service.
+ */
+static int
+ip_vs_sh_reassign(struct ip_vs_sh_state *s, struct ip_vs_service *svc)
+{
+	int i;
+	struct ip_vs_sh_bucket *b;
+	struct list_head *p;
+	struct ip_vs_dest *dest;
+	int d_count;
+	bool empty;
+
+	b = &s->buckets[0];
+	p = &svc->destinations;
+	empty = list_empty(p);
+	d_count = 0;
+	for (i=0; i<IP_VS_SH_TAB_SIZE; i++) {
+		dest = rcu_dereference_protected(b->dest, 1);
+		if (dest)
+			ip_vs_dest_put(dest);
+		if (empty)
+			RCU_INIT_POINTER(b->dest, NULL);
+		else {
+			if (p == &svc->destinations)
+				p = p->next;
+
+			dest = list_entry(p, struct ip_vs_dest, n_list);
+			ip_vs_dest_hold(dest);
+			RCU_INIT_POINTER(b->dest, dest);
+
+			IP_VS_DBG_BUF(6, "assigned i: %d dest: %s weight: %d\n",
+				      i, IP_VS_DBG_ADDR(svc->af, &dest->addr),
+				      atomic_read(&dest->weight));
+
+			/* Don't move to next dest until filling weight */
+			if (++d_count >= atomic_read(&dest->weight)) {
+				p = p->next;
+				d_count = 0;
+			}
+
+		}
+		b++;
+	}
+	return 0;
+}
+
+
+/*
+ *      Flush all the hash buckets of the specified table.
+ */
+static void ip_vs_sh_flush(struct ip_vs_sh_state *s)
+{
+	int i;
+	struct ip_vs_sh_bucket *b;
+	struct ip_vs_dest *dest;
+
+	b = &s->buckets[0];
+	for (i=0; i<IP_VS_SH_TAB_SIZE; i++) {
+		dest = rcu_dereference_protected(b->dest, 1);
+		if (dest) {
+			ip_vs_dest_put(dest);
+			RCU_INIT_POINTER(b->dest, NULL);
+		}
+		b++;
+	}
+}
+
+
+static int ip_vs_sh_init_svc(struct ip_vs_service *svc)
+{
+	struct ip_vs_sh_state *s;
+
+	/* allocate the SH table for this service */
+	s = kzalloc(sizeof(struct ip_vs_sh_state), GFP_KERNEL);
+	if (s == NULL)
+		return -ENOMEM;
+
+	svc->sched_data = s;
+	IP_VS_DBG(6, "SH hash table (memory=%Zdbytes) allocated for "
+		  "current service\n",
+		  sizeof(struct ip_vs_sh_bucket)*IP_VS_SH_TAB_SIZE);
+
+	/* assign the hash buckets with current dests */
+	ip_vs_sh_reassign(s, svc);
+
+	return 0;
+}
+
+
+static void ip_vs_sh_done_svc(struct ip_vs_service *svc)
+{
+	struct ip_vs_sh_state *s = svc->sched_data;
+
+	/* got to clean up hash buckets here */
+	ip_vs_sh_flush(s);
+
+	/* release the table itself */
+	kfree_rcu(s, rcu_head);
+	IP_VS_DBG(6, "SH hash table (memory=%Zdbytes) released\n",
+		  sizeof(struct ip_vs_sh_bucket)*IP_VS_SH_TAB_SIZE);
+}
+
+
+static int ip_vs_sh_dest_changed(struct ip_vs_service *svc,
+				 struct ip_vs_dest *dest)
+{
+	struct ip_vs_sh_state *s = svc->sched_data;
+
+	/* assign the hash buckets with the updated service */
+	ip_vs_sh_reassign(s, svc);
+
+	return 0;
+}
+
+
+/*
+ *      If the dest flags is set with IP_VS_DEST_F_OVERLOAD,
+ *      consider that the server is overloaded here.
+ */
+static inline int is_overloaded(struct ip_vs_dest *dest)
+{
+	return dest->flags & IP_VS_DEST_F_OVERLOAD;
+}
+
+
+/*
+ *      Source Hashing scheduling
+ */
+static struct ip_vs_dest *
+ip_vs_sh_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
+{
+	struct ip_vs_dest *dest;
+	struct ip_vs_sh_state *s;
+	struct ip_vs_iphdr iph;
+
+	ip_vs_fill_iph_addr_only(svc->af, skb, &iph);
+
+	IP_VS_DBG(6, "ip_vs_sh_schedule(): Scheduling...\n");
+
+	s = (struct ip_vs_sh_state *) svc->sched_data;
+	dest = ip_vs_sh_get(svc->af, s, &iph.saddr);
+	if (!dest
+	    || !(dest->flags & IP_VS_DEST_F_AVAILABLE)
+	    || atomic_read(&dest->weight) <= 0
+	    || is_overloaded(dest)) {
+		ip_vs_scheduler_err(svc, "no destination available");
+		return NULL;
+	}
+
+	IP_VS_DBG_BUF(6, "SH: source IP address %s --> server %s:%d\n",
+		      IP_VS_DBG_ADDR(svc->af, &iph.saddr),
+		      IP_VS_DBG_ADDR(svc->af, &dest->addr),
+		      ntohs(dest->port));
+
+	return dest;
+}
+
+
+/*
+ *      IPVS SH Scheduler structure
+ */
+static struct ip_vs_scheduler ip_vs_sh_scheduler =
+{
+	.name =			"sh",
+	.refcnt =		ATOMIC_INIT(0),
+	.module =		THIS_MODULE,
+	.n_list	 =		LIST_HEAD_INIT(ip_vs_sh_scheduler.n_list),
+	.init_service =		ip_vs_sh_init_svc,
+	.done_service =		ip_vs_sh_done_svc,
+	.add_dest =		ip_vs_sh_dest_changed,
+	.del_dest =		ip_vs_sh_dest_changed,
+	.upd_dest =		ip_vs_sh_dest_changed,
+	.schedule =		ip_vs_sh_schedule,
+};
+
+
+static int __init ip_vs_sh_init(void)
+{
+	return register_ip_vs_scheduler(&ip_vs_sh_scheduler);
+}
+
+
+static void __exit ip_vs_sh_cleanup(void)
+{
+	unregister_ip_vs_scheduler(&ip_vs_sh_scheduler);
+	synchronize_rcu();
+}
+
+
+module_init(ip_vs_sh_init);
+module_exit(ip_vs_sh_cleanup);
+MODULE_LICENSE("GPL");