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
8 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
9 * Peter Kese <peter.kese@ijs.si>
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.
20 #define KMSG_COMPONENT "IPVS"
21 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
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>
30 #include <net/ip_vs.h>
32 EXPORT_SYMBOL(ip_vs_scheduler_err);
36 static LIST_HEAD(ip_vs_schedulers);
38 /* semaphore for schedulers */
39 static DEFINE_MUTEX(ip_vs_sched_mutex);
43 * Bind a service with a scheduler
45 int ip_vs_bind_scheduler(struct ip_vs_service *svc,
46 struct ip_vs_scheduler *scheduler)
50 if (scheduler->init_service) {
51 ret = scheduler->init_service(svc);
53 pr_err("%s(): init error\n", __func__);
57 rcu_assign_pointer(svc->scheduler, scheduler);
63 * Unbind a service with its scheduler
65 void ip_vs_unbind_scheduler(struct ip_vs_service *svc,
66 struct ip_vs_scheduler *sched)
68 struct ip_vs_scheduler *cur_sched;
70 cur_sched = rcu_dereference_protected(svc->scheduler, 1);
71 /* This check proves that old 'sched' was installed */
75 if (sched->done_service)
76 sched->done_service(svc);
77 /* svc->scheduler can not be set to NULL */
82 * Get scheduler in the scheduler list by name
84 static struct ip_vs_scheduler *ip_vs_sched_getbyname(const char *sched_name)
86 struct ip_vs_scheduler *sched;
88 IP_VS_DBG(2, "%s(): sched_name \"%s\"\n", __func__, sched_name);
90 mutex_lock(&ip_vs_sched_mutex);
92 list_for_each_entry(sched, &ip_vs_schedulers, n_list) {
94 * Test and get the modules atomically
96 if (sched->module && !try_module_get(sched->module)) {
98 * This scheduler is just deleted
102 if (strcmp(sched_name, sched->name)==0) {
104 mutex_unlock(&ip_vs_sched_mutex);
108 module_put(sched->module);
111 mutex_unlock(&ip_vs_sched_mutex);
117 * Lookup scheduler and try to load it if it doesn't exist
119 struct ip_vs_scheduler *ip_vs_scheduler_get(const char *sched_name)
121 struct ip_vs_scheduler *sched;
124 * Search for the scheduler by sched_name
126 sched = ip_vs_sched_getbyname(sched_name);
129 * If scheduler not found, load the module and search again
132 request_module("ip_vs_%s", sched_name);
133 sched = ip_vs_sched_getbyname(sched_name);
139 void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler)
141 if (scheduler && scheduler->module)
142 module_put(scheduler->module);
146 * Common error output helper for schedulers
149 void ip_vs_scheduler_err(struct ip_vs_service *svc, const char *msg)
151 struct ip_vs_scheduler *sched;
153 sched = rcu_dereference(svc->scheduler);
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);
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);
171 * Register a scheduler in the scheduler list
173 int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
175 struct ip_vs_scheduler *sched;
178 pr_err("%s(): NULL arg\n", __func__);
182 if (!scheduler->name) {
183 pr_err("%s(): NULL scheduler_name\n", __func__);
187 /* increase the module use count */
188 ip_vs_use_count_inc();
190 mutex_lock(&ip_vs_sched_mutex);
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);
201 * Make sure that the scheduler with this name doesn't exist
202 * in the scheduler list.
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);
214 * Add it into the d-linked scheduler list
216 list_add(&scheduler->n_list, &ip_vs_schedulers);
217 mutex_unlock(&ip_vs_sched_mutex);
219 pr_info("[%s] scheduler registered.\n", scheduler->name);
226 * Unregister a scheduler from the scheduler list
228 int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler)
231 pr_err("%s(): NULL arg\n", __func__);
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);
244 * Remove it from the d-linked scheduler list
246 list_del(&scheduler->n_list);
247 mutex_unlock(&ip_vs_sched_mutex);
249 /* decrease the module use count */
250 ip_vs_use_count_dec();
252 pr_info("[%s] scheduler unregistered.\n", scheduler->name);