Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 255 insertions, 0 deletions

diff --git a/net/ipv4/ipvs/ip_vs_sh.c b/net/ipv4/ipvs/ip_vs_sh.c
new file mode 100644
index 000000000000..6f7c50e44a39
--- /dev/null
+++ b/net/ipv4/ipvs/ip_vs_sh.c
@@ -0,0 +1,255 @@
+/*
+ * IPVS:        Source Hashing scheduling module
+ *
+ * Version:     $Id: ip_vs_sh.c,v 1.5 2002/09/15 08:14:08 wensong Exp $
+ *
+ * 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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+#include <net/ip_vs.h>
+
+
+/*
+ *      IPVS SH bucket
+ */
+struct ip_vs_sh_bucket {
+        struct ip_vs_dest       *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)
+
+
+/*
+ *      Returns hash value for IPVS SH entry
+ */
+static inline unsigned ip_vs_sh_hashkey(__u32 addr)
+{
+        return (ntohl(addr)*2654435761UL) & IP_VS_SH_TAB_MASK;
+}
+
+
+/*
+ *      Get ip_vs_dest associated with supplied parameters.
+ */
+static inline struct ip_vs_dest *
+ip_vs_sh_get(struct ip_vs_sh_bucket *tbl, __u32 addr)
+{
+        return (tbl[ip_vs_sh_hashkey(addr)]).dest;
+}
+
+
+/*
+ *      Assign all the hash buckets of the specified table with the service.
+ */
+static int
+ip_vs_sh_assign(struct ip_vs_sh_bucket *tbl, struct ip_vs_service *svc)
+{
+        int i;
+        struct ip_vs_sh_bucket *b;
+        struct list_head *p;
+        struct ip_vs_dest *dest;
+
+        b = tbl;
+        p = &svc->destinations;
+        for (i=0; i<IP_VS_SH_TAB_SIZE; i++) {
+                if (list_empty(p)) {
+                        b->dest = NULL;
+                } else {
+                        if (p == &svc->destinations)
+                                p = p->next;
+
+                        dest = list_entry(p, struct ip_vs_dest, n_list);
+                        atomic_inc(&dest->refcnt);
+                        b->dest = dest;
+
+                        p = p->next;
+                }
+                b++;
+        }
+        return 0;
+}
+
+
+/*
+ *      Flush all the hash buckets of the specified table.
+ */
+static void ip_vs_sh_flush(struct ip_vs_sh_bucket *tbl)
+{
+        int i;
+        struct ip_vs_sh_bucket *b;
+
+        b = tbl;
+        for (i=0; i<IP_VS_SH_TAB_SIZE; i++) {
+                if (b->dest) {
+                        atomic_dec(&b->dest->refcnt);
+                        b->dest = NULL;
+                }
+                b++;
+        }
+}
+
+
+static int ip_vs_sh_init_svc(struct ip_vs_service *svc)
+{
+        struct ip_vs_sh_bucket *tbl;
+
+        /* allocate the SH table for this service */
+        tbl = kmalloc(sizeof(struct ip_vs_sh_bucket)*IP_VS_SH_TAB_SIZE,
+                      GFP_ATOMIC);
+        if (tbl == NULL) {
+                IP_VS_ERR("ip_vs_sh_init_svc(): no memory\n");
+                return -ENOMEM;
+        }
+        svc->sched_data = tbl;
+        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 the updated service */
+        ip_vs_sh_assign(tbl, svc);
+
+        return 0;
+}
+
+
+static int ip_vs_sh_done_svc(struct ip_vs_service *svc)
+{
+        struct ip_vs_sh_bucket *tbl = svc->sched_data;
+
+        /* got to clean up hash buckets here */
+        ip_vs_sh_flush(tbl);
+
+        /* release the table itself */
+        kfree(svc->sched_data);
+        IP_VS_DBG(6, "SH hash table (memory=%Zdbytes) released\n",
+                  sizeof(struct ip_vs_sh_bucket)*IP_VS_SH_TAB_SIZE);
+
+        return 0;
+}
+
+
+static int ip_vs_sh_update_svc(struct ip_vs_service *svc)
+{
+        struct ip_vs_sh_bucket *tbl = svc->sched_data;
+
+        /* got to clean up hash buckets here */
+        ip_vs_sh_flush(tbl);
+
+        /* assign the hash buckets with the updated service */
+        ip_vs_sh_assign(tbl, 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_bucket *tbl;
+        struct iphdr *iph = skb->nh.iph;
+
+        IP_VS_DBG(6, "ip_vs_sh_schedule(): Scheduling...\n");
+
+        tbl = (struct ip_vs_sh_bucket *)svc->sched_data;
+        dest = ip_vs_sh_get(tbl, iph->saddr);
+        if (!dest
+            || !(dest->flags & IP_VS_DEST_F_AVAILABLE)
+            || atomic_read(&dest->weight) <= 0
+            || is_overloaded(dest)) {
+                return NULL;
+        }
+
+        IP_VS_DBG(6, "SH: source IP address %u.%u.%u.%u "
+                  "--> server %u.%u.%u.%u:%d\n",
+                  NIPQUAD(iph->saddr),
+                  NIPQUAD(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,
+        .init_service =         ip_vs_sh_init_svc,
+        .done_service =         ip_vs_sh_done_svc,
+        .update_service =       ip_vs_sh_update_svc,
+        .schedule =             ip_vs_sh_schedule,
+};
+
+
+static int __init ip_vs_sh_init(void)
+{
+        INIT_LIST_HEAD(&ip_vs_sh_scheduler.n_list);
+        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);
+}
+
+
+module_init(ip_vs_sh_init);
+module_exit(ip_vs_sh_cleanup);
+MODULE_LICENSE("GPL");