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- /*
- * IPVS An implementation of the IP virtual server support for the
- * LINUX operating system. IPVS is now implemented as a module
- * over the Netfilter framework. IPVS can be used to build a
- * high-performance and highly available server based on a
- * cluster of servers.
- *
- * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
- * Peter Kese <peter.kese@ijs.si>
- *
- * 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:
- *
- */
- #define KMSG_COMPONENT "IPVS"
- #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
- #include <linux/module.h>
- #include <linux/spinlock.h>
- #include <linux/interrupt.h>
- #include <asm/string.h>
- #include <linux/kmod.h>
- #include <linux/sysctl.h>
- #include <net/ip_vs.h>
- EXPORT_SYMBOL(ip_vs_scheduler_err);
- /*
- * IPVS scheduler list
- */
- static LIST_HEAD(ip_vs_schedulers);
- /* semaphore for schedulers */
- static DEFINE_MUTEX(ip_vs_sched_mutex);
- /*
- * Bind a service with a scheduler
- */
- int ip_vs_bind_scheduler(struct ip_vs_service *svc,
- struct ip_vs_scheduler *scheduler)
- {
- int ret;
- if (scheduler->init_service) {
- ret = scheduler->init_service(svc);
- if (ret) {
- pr_err("%s(): init error\n", __func__);
- return ret;
- }
- }
- rcu_assign_pointer(svc->scheduler, scheduler);
- return 0;
- }
- /*
- * Unbind a service with its scheduler
- */
- void ip_vs_unbind_scheduler(struct ip_vs_service *svc,
- struct ip_vs_scheduler *sched)
- {
- struct ip_vs_scheduler *cur_sched;
- cur_sched = rcu_dereference_protected(svc->scheduler, 1);
- /* This check proves that old 'sched' was installed */
- if (!cur_sched)
- return;
- if (sched->done_service)
- sched->done_service(svc);
- /* svc->scheduler can be set to NULL only by caller */
- }
- /*
- * Get scheduler in the scheduler list by name
- */
- static struct ip_vs_scheduler *ip_vs_sched_getbyname(const char *sched_name)
- {
- struct ip_vs_scheduler *sched;
- IP_VS_DBG(2, "%s(): sched_name \"%s\"\n", __func__, sched_name);
- mutex_lock(&ip_vs_sched_mutex);
- list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
- /*
- * Test and get the modules atomically
- */
- if (sched->module && !try_module_get(sched->module)) {
- /*
- * This scheduler is just deleted
- */
- continue;
- }
- if (strcmp(sched_name, sched->name)==0) {
- /* HIT */
- mutex_unlock(&ip_vs_sched_mutex);
- return sched;
- }
- module_put(sched->module);
- }
- mutex_unlock(&ip_vs_sched_mutex);
- return NULL;
- }
- /*
- * Lookup scheduler and try to load it if it doesn't exist
- */
- struct ip_vs_scheduler *ip_vs_scheduler_get(const char *sched_name)
- {
- struct ip_vs_scheduler *sched;
- /*
- * Search for the scheduler by sched_name
- */
- sched = ip_vs_sched_getbyname(sched_name);
- /*
- * If scheduler not found, load the module and search again
- */
- if (sched == NULL) {
- request_module("ip_vs_%s", sched_name);
- sched = ip_vs_sched_getbyname(sched_name);
- }
- return sched;
- }
- void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler)
- {
- if (scheduler)
- module_put(scheduler->module);
- }
- /*
- * Common error output helper for schedulers
- */
- void ip_vs_scheduler_err(struct ip_vs_service *svc, const char *msg)
- {
- struct ip_vs_scheduler *sched = rcu_dereference(svc->scheduler);
- char *sched_name = sched ? sched->name : "none";
- if (svc->fwmark) {
- IP_VS_ERR_RL("%s: FWM %u 0x%08X - %s\n",
- sched_name, svc->fwmark, svc->fwmark, msg);
- #ifdef CONFIG_IP_VS_IPV6
- } else if (svc->af == AF_INET6) {
- IP_VS_ERR_RL("%s: %s [%pI6c]:%d - %s\n",
- sched_name, ip_vs_proto_name(svc->protocol),
- &svc->addr.in6, ntohs(svc->port), msg);
- #endif
- } else {
- IP_VS_ERR_RL("%s: %s %pI4:%d - %s\n",
- sched_name, ip_vs_proto_name(svc->protocol),
- &svc->addr.ip, ntohs(svc->port), msg);
- }
- }
- /*
- * Register a scheduler in the scheduler list
- */
- int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
- {
- struct ip_vs_scheduler *sched;
- if (!scheduler) {
- pr_err("%s(): NULL arg\n", __func__);
- return -EINVAL;
- }
- if (!scheduler->name) {
- pr_err("%s(): NULL scheduler_name\n", __func__);
- return -EINVAL;
- }
- /* increase the module use count */
- ip_vs_use_count_inc();
- mutex_lock(&ip_vs_sched_mutex);
- if (!list_empty(&scheduler->n_list)) {
- mutex_unlock(&ip_vs_sched_mutex);
- ip_vs_use_count_dec();
- pr_err("%s(): [%s] scheduler already linked\n",
- __func__, scheduler->name);
- return -EINVAL;
- }
- /*
- * Make sure that the scheduler with this name doesn't exist
- * in the scheduler list.
- */
- list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
- if (strcmp(scheduler->name, sched->name) == 0) {
- mutex_unlock(&ip_vs_sched_mutex);
- ip_vs_use_count_dec();
- pr_err("%s(): [%s] scheduler already existed "
- "in the system\n", __func__, scheduler->name);
- return -EINVAL;
- }
- }
- /*
- * Add it into the d-linked scheduler list
- */
- list_add(&scheduler->n_list, &ip_vs_schedulers);
- mutex_unlock(&ip_vs_sched_mutex);
- pr_info("[%s] scheduler registered.\n", scheduler->name);
- return 0;
- }
- /*
- * Unregister a scheduler from the scheduler list
- */
- int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
- {
- if (!scheduler) {
- pr_err("%s(): NULL arg\n", __func__);
- return -EINVAL;
- }
- mutex_lock(&ip_vs_sched_mutex);
- if (list_empty(&scheduler->n_list)) {
- mutex_unlock(&ip_vs_sched_mutex);
- pr_err("%s(): [%s] scheduler is not in the list. failed\n",
- __func__, scheduler->name);
- return -EINVAL;
- }
- /*
- * Remove it from the d-linked scheduler list
- */
- list_del(&scheduler->n_list);
- mutex_unlock(&ip_vs_sched_mutex);
- /* decrease the module use count */
- ip_vs_use_count_dec();
- pr_info("[%s] scheduler unregistered.\n", scheduler->name);
- return 0;
- }
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