1/* 2 * IPVS An implementation of the IP virtual server support for the 3 * LINUX operating system. IPVS is now implemented as a module 4 * over the Netfilter framework. IPVS can be used to build a 5 * high-performance and highly available server based on a 6 * cluster of servers. 7 * 8 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org> 9 * Peter Kese <peter.kese@ijs.si> 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License 13 * as published by the Free Software Foundation; either version 14 * 2 of the License, or (at your option) any later version. 15 * 16 * Changes: 17 * 18 */ 19 20#define KMSG_COMPONENT "IPVS" 21#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 22 23#include <linux/module.h> 24#include <linux/spinlock.h> 25#include <linux/interrupt.h> 26#include <asm/string.h> 27#include <linux/kmod.h> 28#include <linux/sysctl.h> 29 30#include <net/ip_vs.h> 31 32/* 33 * IPVS scheduler list 34 */ 35static LIST_HEAD(ip_vs_schedulers); 36 37/* lock for service table */ 38static DEFINE_RWLOCK(__ip_vs_sched_lock); 39 40 41/* 42 * Bind a service with a scheduler 43 */ 44int ip_vs_bind_scheduler(struct ip_vs_service *svc, 45 struct ip_vs_scheduler *scheduler) 46{ 47 int ret; 48 49 if (svc == NULL) { 50 pr_err("%s(): svc arg NULL\n", __func__); 51 return -EINVAL; 52 } 53 if (scheduler == NULL) { 54 pr_err("%s(): scheduler arg NULL\n", __func__); 55 return -EINVAL; 56 } 57 58 svc->scheduler = scheduler; 59 60 if (scheduler->init_service) { 61 ret = scheduler->init_service(svc); 62 if (ret) { 63 pr_err("%s(): init error\n", __func__); 64 return ret; 65 } 66 } 67 68 return 0; 69} 70 71 72/* 73 * Unbind a service with its scheduler 74 */ 75int ip_vs_unbind_scheduler(struct ip_vs_service *svc) 76{ 77 struct ip_vs_scheduler *sched; 78 79 if (svc == NULL) { 80 pr_err("%s(): svc arg NULL\n", __func__); 81 return -EINVAL; 82 } 83 84 sched = svc->scheduler; 85 if (sched == NULL) { 86 pr_err("%s(): svc isn't bound\n", __func__); 87 return -EINVAL; 88 } 89 90 if (sched->done_service) { 91 if (sched->done_service(svc) != 0) { 92 pr_err("%s(): done error\n", __func__); 93 return -EINVAL; 94 } 95 } 96 97 svc->scheduler = NULL; 98 return 0; 99} 100 101 102/* 103 * Get scheduler in the scheduler list by name 104 */ 105static struct ip_vs_scheduler *ip_vs_sched_getbyname(const char *sched_name) 106{ 107 struct ip_vs_scheduler *sched; 108 109 IP_VS_DBG(2, "%s(): sched_name \"%s\"\n", __func__, sched_name); 110 111 read_lock_bh(&__ip_vs_sched_lock); 112 113 list_for_each_entry(sched, &ip_vs_schedulers, n_list) { 114 /* 115 * Test and get the modules atomically 116 */ 117 if (sched->module && !try_module_get(sched->module)) { 118 /* 119 * This scheduler is just deleted 120 */ 121 continue; 122 } 123 if (strcmp(sched_name, sched->name)==0) { 124 /* HIT */ 125 read_unlock_bh(&__ip_vs_sched_lock); 126 return sched; 127 } 128 if (sched->module) 129 module_put(sched->module); 130 } 131 132 read_unlock_bh(&__ip_vs_sched_lock); 133 return NULL; 134} 135 136 137/* 138 * Lookup scheduler and try to load it if it doesn't exist 139 */ 140struct ip_vs_scheduler *ip_vs_scheduler_get(const char *sched_name) 141{ 142 struct ip_vs_scheduler *sched; 143 144 /* 145 * Search for the scheduler by sched_name 146 */ 147 sched = ip_vs_sched_getbyname(sched_name); 148 149 /* 150 * If scheduler not found, load the module and search again 151 */ 152 if (sched == NULL) { 153 request_module("ip_vs_%s", sched_name); 154 sched = ip_vs_sched_getbyname(sched_name); 155 } 156 157 return sched; 158} 159 160void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler) 161{ 162 if (scheduler->module) 163 module_put(scheduler->module); 164} 165 166 167/* 168 * Register a scheduler in the scheduler list 169 */ 170int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler) 171{ 172 struct ip_vs_scheduler *sched; 173 174 if (!scheduler) { 175 pr_err("%s(): NULL arg\n", __func__); 176 return -EINVAL; 177 } 178 179 if (!scheduler->name) { 180 pr_err("%s(): NULL scheduler_name\n", __func__); 181 return -EINVAL; 182 } 183 184 /* increase the module use count */ 185 ip_vs_use_count_inc(); 186 187 write_lock_bh(&__ip_vs_sched_lock); 188 189 if (!list_empty(&scheduler->n_list)) { 190 write_unlock_bh(&__ip_vs_sched_lock); 191 ip_vs_use_count_dec(); 192 pr_err("%s(): [%s] scheduler already linked\n", 193 __func__, scheduler->name); 194 return -EINVAL; 195 } 196 197 /* 198 * Make sure that the scheduler with this name doesn't exist 199 * in the scheduler list. 200 */ 201 list_for_each_entry(sched, &ip_vs_schedulers, n_list) { 202 if (strcmp(scheduler->name, sched->name) == 0) { 203 write_unlock_bh(&__ip_vs_sched_lock); 204 ip_vs_use_count_dec(); 205 pr_err("%s(): [%s] scheduler already existed " 206 "in the system\n", __func__, scheduler->name); 207 return -EINVAL; 208 } 209 } 210 /* 211 * Add it into the d-linked scheduler list 212 */ 213 list_add(&scheduler->n_list, &ip_vs_schedulers); 214 write_unlock_bh(&__ip_vs_sched_lock); 215 216 pr_info("[%s] scheduler registered.\n", scheduler->name); 217 218 return 0; 219} 220 221 222/* 223 * Unregister a scheduler from the scheduler list 224 */ 225int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler) 226{ 227 if (!scheduler) { 228 pr_err("%s(): NULL arg\n", __func__); 229 return -EINVAL; 230 } 231 232 write_lock_bh(&__ip_vs_sched_lock); 233 if (list_empty(&scheduler->n_list)) { 234 write_unlock_bh(&__ip_vs_sched_lock); 235 pr_err("%s(): [%s] scheduler is not in the list. failed\n", 236 __func__, scheduler->name); 237 return -EINVAL; 238 } 239 240 /* 241 * Remove it from the d-linked scheduler list 242 */ 243 list_del(&scheduler->n_list); 244 write_unlock_bh(&__ip_vs_sched_lock); 245 246 /* decrease the module use count */ 247 ip_vs_use_count_dec(); 248 249 pr_info("[%s] scheduler unregistered.\n", scheduler->name); 250 251 return 0; 252} 253