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@@ -1,261 +0,0 @@
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-/*
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- * IPVS: Destination Hashing scheduling module
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- *
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- * Authors: Wensong Zhang <wensong@gnuchina.org>
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- *
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- * Inspired by the consistent hashing scheduler patch from
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- * Thomas Proell <proellt@gmx.de>
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- *
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- * This program is free software; you can redistribute it and/or
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- * modify it under the terms of the GNU General Public License
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- * as published by the Free Software Foundation; either version
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- * 2 of the License, or (at your option) any later version.
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- *
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- * Changes:
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- *
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- */
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-
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-/*
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- * The dh algorithm is to select server by the hash key of destination IP
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- * address. The pseudo code is as follows:
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- *
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- * n <- servernode[dest_ip];
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- * if (n is dead) OR
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- * (n is overloaded) OR (n.weight <= 0) then
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- * return NULL;
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- *
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- * return n;
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- *
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- * Notes that servernode is a 256-bucket hash table that maps the hash
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- * index derived from packet destination IP address to the current server
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- * array. If the dh scheduler is used in cache cluster, it is good to
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- * combine it with cache_bypass feature. When the statically assigned
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- * server is dead or overloaded, the load balancer can bypass the cache
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- * server and send requests to the original server directly.
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- *
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- */
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-
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-#include <linux/ip.h>
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-#include <linux/module.h>
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-#include <linux/kernel.h>
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-#include <linux/skbuff.h>
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-
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-#include <net/ip_vs.h>
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-
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-
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-/*
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- * IPVS DH bucket
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- */
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-struct ip_vs_dh_bucket {
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- struct ip_vs_dest *dest; /* real server (cache) */
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-};
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-
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-/*
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- * for IPVS DH entry hash table
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- */
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-#ifndef CONFIG_IP_VS_DH_TAB_BITS
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-#define CONFIG_IP_VS_DH_TAB_BITS 8
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-#endif
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-#define IP_VS_DH_TAB_BITS CONFIG_IP_VS_DH_TAB_BITS
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-#define IP_VS_DH_TAB_SIZE (1 << IP_VS_DH_TAB_BITS)
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-#define IP_VS_DH_TAB_MASK (IP_VS_DH_TAB_SIZE - 1)
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-
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-
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-/*
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- * Returns hash value for IPVS DH entry
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- */
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-static inline unsigned ip_vs_dh_hashkey(__be32 addr)
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-{
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- return (ntohl(addr)*2654435761UL) & IP_VS_DH_TAB_MASK;
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-}
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-
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-
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-/*
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- * Get ip_vs_dest associated with supplied parameters.
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- */
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-static inline struct ip_vs_dest *
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-ip_vs_dh_get(struct ip_vs_dh_bucket *tbl, __be32 addr)
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-{
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- return (tbl[ip_vs_dh_hashkey(addr)]).dest;
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-}
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-
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-
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-/*
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- * Assign all the hash buckets of the specified table with the service.
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- */
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-static int
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-ip_vs_dh_assign(struct ip_vs_dh_bucket *tbl, struct ip_vs_service *svc)
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-{
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- int i;
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- struct ip_vs_dh_bucket *b;
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- struct list_head *p;
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- struct ip_vs_dest *dest;
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-
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- b = tbl;
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- p = &svc->destinations;
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- for (i=0; i<IP_VS_DH_TAB_SIZE; i++) {
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- if (list_empty(p)) {
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- b->dest = NULL;
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- } else {
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- if (p == &svc->destinations)
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- p = p->next;
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-
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- dest = list_entry(p, struct ip_vs_dest, n_list);
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- atomic_inc(&dest->refcnt);
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- b->dest = dest;
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-
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- p = p->next;
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- }
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- b++;
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- }
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- return 0;
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-}
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-
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-
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-/*
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- * Flush all the hash buckets of the specified table.
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- */
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-static void ip_vs_dh_flush(struct ip_vs_dh_bucket *tbl)
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-{
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- int i;
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- struct ip_vs_dh_bucket *b;
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-
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- b = tbl;
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- for (i=0; i<IP_VS_DH_TAB_SIZE; i++) {
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- if (b->dest) {
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- atomic_dec(&b->dest->refcnt);
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- b->dest = NULL;
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- }
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- b++;
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- }
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-}
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-
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-
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-static int ip_vs_dh_init_svc(struct ip_vs_service *svc)
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-{
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- struct ip_vs_dh_bucket *tbl;
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-
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- /* allocate the DH table for this service */
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- tbl = kmalloc(sizeof(struct ip_vs_dh_bucket)*IP_VS_DH_TAB_SIZE,
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- GFP_ATOMIC);
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- if (tbl == NULL) {
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- IP_VS_ERR("ip_vs_dh_init_svc(): no memory\n");
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- return -ENOMEM;
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- }
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- svc->sched_data = tbl;
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- IP_VS_DBG(6, "DH hash table (memory=%Zdbytes) allocated for "
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- "current service\n",
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- sizeof(struct ip_vs_dh_bucket)*IP_VS_DH_TAB_SIZE);
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-
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- /* assign the hash buckets with the updated service */
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- ip_vs_dh_assign(tbl, svc);
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-
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- return 0;
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-}
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-
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-
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-static int ip_vs_dh_done_svc(struct ip_vs_service *svc)
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-{
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- struct ip_vs_dh_bucket *tbl = svc->sched_data;
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-
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- /* got to clean up hash buckets here */
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- ip_vs_dh_flush(tbl);
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-
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- /* release the table itself */
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- kfree(svc->sched_data);
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- IP_VS_DBG(6, "DH hash table (memory=%Zdbytes) released\n",
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- sizeof(struct ip_vs_dh_bucket)*IP_VS_DH_TAB_SIZE);
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-
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- return 0;
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-}
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-
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-
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-static int ip_vs_dh_update_svc(struct ip_vs_service *svc)
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-{
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- struct ip_vs_dh_bucket *tbl = svc->sched_data;
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-
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- /* got to clean up hash buckets here */
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- ip_vs_dh_flush(tbl);
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-
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- /* assign the hash buckets with the updated service */
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- ip_vs_dh_assign(tbl, svc);
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-
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- return 0;
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-}
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-
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-
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-/*
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- * If the dest flags is set with IP_VS_DEST_F_OVERLOAD,
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- * consider that the server is overloaded here.
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- */
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-static inline int is_overloaded(struct ip_vs_dest *dest)
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-{
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- return dest->flags & IP_VS_DEST_F_OVERLOAD;
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-}
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-
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-
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-/*
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- * Destination hashing scheduling
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- */
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-static struct ip_vs_dest *
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-ip_vs_dh_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
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-{
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- struct ip_vs_dest *dest;
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- struct ip_vs_dh_bucket *tbl;
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- struct iphdr *iph = ip_hdr(skb);
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-
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- IP_VS_DBG(6, "ip_vs_dh_schedule(): Scheduling...\n");
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-
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- tbl = (struct ip_vs_dh_bucket *)svc->sched_data;
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- dest = ip_vs_dh_get(tbl, iph->daddr);
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- if (!dest
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- || !(dest->flags & IP_VS_DEST_F_AVAILABLE)
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- || atomic_read(&dest->weight) <= 0
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- || is_overloaded(dest)) {
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- return NULL;
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- }
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-
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- IP_VS_DBG(6, "DH: destination IP address %u.%u.%u.%u "
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- "--> server %u.%u.%u.%u:%d\n",
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- NIPQUAD(iph->daddr),
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- NIPQUAD(dest->addr.ip),
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- ntohs(dest->port));
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-
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- return dest;
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-}
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-
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-
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-/*
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- * IPVS DH Scheduler structure
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- */
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-static struct ip_vs_scheduler ip_vs_dh_scheduler =
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-{
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- .name = "dh",
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- .refcnt = ATOMIC_INIT(0),
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- .module = THIS_MODULE,
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- .n_list = LIST_HEAD_INIT(ip_vs_dh_scheduler.n_list),
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-#ifdef CONFIG_IP_VS_IPV6
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- .supports_ipv6 = 0,
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-#endif
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- .init_service = ip_vs_dh_init_svc,
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- .done_service = ip_vs_dh_done_svc,
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- .update_service = ip_vs_dh_update_svc,
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- .schedule = ip_vs_dh_schedule,
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-};
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-
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-
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-static int __init ip_vs_dh_init(void)
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-{
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- return register_ip_vs_scheduler(&ip_vs_dh_scheduler);
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-}
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-
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-
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-static void __exit ip_vs_dh_cleanup(void)
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-{
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- unregister_ip_vs_scheduler(&ip_vs_dh_scheduler);
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-}
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-
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-
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-module_init(ip_vs_dh_init);
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-module_exit(ip_vs_dh_cleanup);
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-MODULE_LICENSE("GPL");
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