Pileus Git - ~andy/linux/blob - net/netfilter/ipvs/ip_vs_sched.c

   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 EXPORT_SYMBOL(ip_vs_scheduler_err);
  33 /*
  34  *  IPVS scheduler list
  35  */
  36 static LIST_HEAD(ip_vs_schedulers);
  37
  38 /* semaphore for schedulers */
  39 static DEFINE_MUTEX(ip_vs_sched_mutex);
  40
  41
  42 /*
  43  *  Bind a service with a scheduler
  44  */
  45 int ip_vs_bind_scheduler(struct ip_vs_service *svc,
  46                          struct ip_vs_scheduler *scheduler)
  47 {
  48         int ret;
  49
  50         if (scheduler->init_service) {
  51                 ret = scheduler->init_service(svc);
  52                 if (ret) {
  53                         pr_err("%s(): init error\n", __func__);
  54                         return ret;
  55                 }
  56         }
  57         rcu_assign_pointer(svc->scheduler, scheduler);
  58         return 0;
  59 }
  60
  61
  62 /*
  63  *  Unbind a service with its scheduler
  64  */
  65 void ip_vs_unbind_scheduler(struct ip_vs_service *svc,
  66                             struct ip_vs_scheduler *sched)
  67 {
  68         struct ip_vs_scheduler *cur_sched;
  69
  70         cur_sched = rcu_dereference_protected(svc->scheduler, 1);
  71         /* This check proves that old 'sched' was installed */
  72         if (!cur_sched)
  73                 return;
  74
  75         if (sched->done_service)
  76                 sched->done_service(svc);
  77         /* svc->scheduler can not be set to NULL */
  78 }
  79
  80
  81 /*
  82  *  Get scheduler in the scheduler list by name
  83  */
  84 static struct ip_vs_scheduler *ip_vs_sched_getbyname(const char *sched_name)
  85 {
  86         struct ip_vs_scheduler *sched;
  87
  88         IP_VS_DBG(2, "%s(): sched_name \"%s\"\n", __func__, sched_name);
  89
  90         mutex_lock(&ip_vs_sched_mutex);
  91
  92         list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
  93                 /*
  94                  * Test and get the modules atomically
  95                  */
  96                 if (sched->module && !try_module_get(sched->module)) {
  97                         /*
  98                          * This scheduler is just deleted
  99                          */
 100                         continue;
 101                 }
 102                 if (strcmp(sched_name, sched->name)==0) {
 103                         /* HIT */
 104                         mutex_unlock(&ip_vs_sched_mutex);
 105                         return sched;
 106                 }
 107                 if (sched->module)
 108                         module_put(sched->module);
 109         }
 110
 111         mutex_unlock(&ip_vs_sched_mutex);
 112         return NULL;
 113 }
 114
 115
 116 /*
 117  *  Lookup scheduler and try to load it if it doesn't exist
 118  */
 119 struct ip_vs_scheduler *ip_vs_scheduler_get(const char *sched_name)
 120 {
 121         struct ip_vs_scheduler *sched;
 122
 123         /*
 124          *  Search for the scheduler by sched_name
 125          */
 126         sched = ip_vs_sched_getbyname(sched_name);
 127
 128         /*
 129          *  If scheduler not found, load the module and search again
 130          */
 131         if (sched == NULL) {
 132                 request_module("ip_vs_%s", sched_name);
 133                 sched = ip_vs_sched_getbyname(sched_name);
 134         }
 135
 136         return sched;
 137 }
 138
 139 void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler)
 140 {
 141         if (scheduler && scheduler->module)
 142                 module_put(scheduler->module);
 143 }
 144
 145 /*
 146  * Common error output helper for schedulers
 147  */
 148
 149 void ip_vs_scheduler_err(struct ip_vs_service *svc, const char *msg)
 150 {
 151         struct ip_vs_scheduler *sched;
 152
 153         sched = rcu_dereference(svc->scheduler);
 154         if (svc->fwmark) {
 155                 IP_VS_ERR_RL("%s: FWM %u 0x%08X - %s\n",
 156                              sched->name, svc->fwmark, svc->fwmark, msg);
 157 #ifdef CONFIG_IP_VS_IPV6
 158         } else if (svc->af == AF_INET6) {
 159                 IP_VS_ERR_RL("%s: %s [%pI6c]:%d - %s\n",
 160                              sched->name, ip_vs_proto_name(svc->protocol),
 161                              &svc->addr.in6, ntohs(svc->port), msg);
 162 #endif
 163         } else {
 164                 IP_VS_ERR_RL("%s: %s %pI4:%d - %s\n",
 165                              sched->name, ip_vs_proto_name(svc->protocol),
 166                              &svc->addr.ip, ntohs(svc->port), msg);
 167         }
 168 }
 169
 170 /*
 171  *  Register a scheduler in the scheduler list
 172  */
 173 int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
 174 {
 175         struct ip_vs_scheduler *sched;
 176
 177         if (!scheduler) {
 178                 pr_err("%s(): NULL arg\n", __func__);
 179                 return -EINVAL;
 180         }
 181
 182         if (!scheduler->name) {
 183                 pr_err("%s(): NULL scheduler_name\n", __func__);
 184                 return -EINVAL;
 185         }
 186
 187         /* increase the module use count */
 188         ip_vs_use_count_inc();
 189
 190         mutex_lock(&ip_vs_sched_mutex);
 191
 192         if (!list_empty(&scheduler->n_list)) {
 193                 mutex_unlock(&ip_vs_sched_mutex);
 194                 ip_vs_use_count_dec();
 195                 pr_err("%s(): [%s] scheduler already linked\n",
 196                        __func__, scheduler->name);
 197                 return -EINVAL;
 198         }
 199
 200         /*
 201          *  Make sure that the scheduler with this name doesn't exist
 202          *  in the scheduler list.
 203          */
 204         list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
 205                 if (strcmp(scheduler->name, sched->name) == 0) {
 206                         mutex_unlock(&ip_vs_sched_mutex);
 207                         ip_vs_use_count_dec();
 208                         pr_err("%s(): [%s] scheduler already existed "
 209                                "in the system\n", __func__, scheduler->name);
 210                         return -EINVAL;
 211                 }
 212         }
 213         /*
 214          *      Add it into the d-linked scheduler list
 215          */
 216         list_add(&scheduler->n_list, &ip_vs_schedulers);
 217         mutex_unlock(&ip_vs_sched_mutex);
 218
 219         pr_info("[%s] scheduler registered.\n", scheduler->name);
 220
 221         return 0;
 222 }
 223
 224
 225 /*
 226  *  Unregister a scheduler from the scheduler list
 227  */
 228 int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
 229 {
 230         if (!scheduler) {
 231                 pr_err("%s(): NULL arg\n", __func__);
 232                 return -EINVAL;
 233         }
 234
 235         mutex_lock(&ip_vs_sched_mutex);
 236         if (list_empty(&scheduler->n_list)) {
 237                 mutex_unlock(&ip_vs_sched_mutex);
 238                 pr_err("%s(): [%s] scheduler is not in the list. failed\n",
 239                        __func__, scheduler->name);
 240                 return -EINVAL;
 241         }
 242
 243         /*
 244          *      Remove it from the d-linked scheduler list
 245          */
 246         list_del(&scheduler->n_list);
 247         mutex_unlock(&ip_vs_sched_mutex);
 248
 249         /* decrease the module use count */
 250         ip_vs_use_count_dec();
 251
 252         pr_info("[%s] scheduler unregistered.\n", scheduler->name);
 253
 254         return 0;
 255 }