1 /* 2 * IPVS: Weighted Fail Over module 3 * 4 * Authors: Kenny Mathis <kmathis@chokepoint.net> 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 * 11 * Changes: 12 * Kenny Mathis : added initial functionality based on weight 13 * 14 */ 15 16 #define KMSG_COMPONENT "IPVS" 17 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 18 19 #include <linux/module.h> 20 #include <linux/kernel.h> 21 22 #include <net/ip_vs.h> 23 24 /* Weighted Fail Over Module */ 25 static struct ip_vs_dest * 26 ip_vs_fo_schedule(struct ip_vs_service *svc, const struct sk_buff *skb, 27 struct ip_vs_iphdr *iph) 28 { 29 struct ip_vs_dest *dest, *hweight = NULL; 30 int hw = 0; /* Track highest weight */ 31 32 IP_VS_DBG(6, "ip_vs_fo_schedule(): Scheduling...\n"); 33 34 /* Basic failover functionality 35 * Find virtual server with highest weight and send it traffic 36 */ 37 list_for_each_entry_rcu(dest, &svc->destinations, n_list) { 38 if (!(dest->flags & IP_VS_DEST_F_OVERLOAD) && 39 atomic_read(&dest->weight) > hw) { 40 hweight = dest; 41 hw = atomic_read(&dest->weight); 42 } 43 } 44 45 if (hweight) { 46 IP_VS_DBG_BUF(6, "FO: server %s:%u activeconns %d weight %d\n", 47 IP_VS_DBG_ADDR(hweight->af, &hweight->addr), 48 ntohs(hweight->port), 49 atomic_read(&hweight->activeconns), 50 atomic_read(&hweight->weight)); 51 return hweight; 52 } 53 54 ip_vs_scheduler_err(svc, "no destination available"); 55 return NULL; 56 } 57 58 static struct ip_vs_scheduler ip_vs_fo_scheduler = { 59 .name = "fo", 60 .refcnt = ATOMIC_INIT(0), 61 .module = THIS_MODULE, 62 .n_list = LIST_HEAD_INIT(ip_vs_fo_scheduler.n_list), 63 .schedule = ip_vs_fo_schedule, 64 }; 65 66 static int __init ip_vs_fo_init(void) 67 { 68 return register_ip_vs_scheduler(&ip_vs_fo_scheduler); 69 } 70 71 static void __exit ip_vs_fo_cleanup(void) 72 { 73 unregister_ip_vs_scheduler(&ip_vs_fo_scheduler); 74 synchronize_rcu(); 75 } 76 77 module_init(ip_vs_fo_init); 78 module_exit(ip_vs_fo_cleanup); 79 MODULE_LICENSE("GPL"); 80