1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * IPVS An implementation of the IP virtual server support for the |
4 | * LINUX operating system. IPVS is now implemented as a module |
5 | * over the Netfilter framework. IPVS can be used to build a |
6 | * high-performance and highly available server based on a |
7 | * cluster of servers. |
8 | * |
9 | * Authors: Wensong Zhang <wensong@linuxvirtualserver.org> |
10 | * Peter Kese <peter.kese@ijs.si> |
11 | * |
12 | * Changes: |
13 | */ |
14 | |
15 | #define KMSG_COMPONENT "IPVS" |
16 | #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt |
17 | |
18 | #include <linux/module.h> |
19 | #include <linux/spinlock.h> |
20 | #include <linux/interrupt.h> |
21 | #include <asm/string.h> |
22 | #include <linux/kmod.h> |
23 | #include <linux/sysctl.h> |
24 | |
25 | #include <net/ip_vs.h> |
26 | |
27 | EXPORT_SYMBOL(ip_vs_scheduler_err); |
28 | /* |
29 | * IPVS scheduler list |
30 | */ |
31 | static LIST_HEAD(ip_vs_schedulers); |
32 | |
33 | /* semaphore for schedulers */ |
34 | static DEFINE_MUTEX(ip_vs_sched_mutex); |
35 | |
36 | |
37 | /* |
38 | * Bind a service with a scheduler |
39 | */ |
40 | int ip_vs_bind_scheduler(struct ip_vs_service *svc, |
41 | struct ip_vs_scheduler *scheduler) |
42 | { |
43 | int ret; |
44 | |
45 | if (scheduler->init_service) { |
46 | ret = scheduler->init_service(svc); |
47 | if (ret) { |
48 | pr_err("%s(): init error\n" , __func__); |
49 | return ret; |
50 | } |
51 | } |
52 | rcu_assign_pointer(svc->scheduler, scheduler); |
53 | return 0; |
54 | } |
55 | |
56 | |
57 | /* |
58 | * Unbind a service with its scheduler |
59 | */ |
60 | void ip_vs_unbind_scheduler(struct ip_vs_service *svc, |
61 | struct ip_vs_scheduler *sched) |
62 | { |
63 | struct ip_vs_scheduler *cur_sched; |
64 | |
65 | cur_sched = rcu_dereference_protected(svc->scheduler, 1); |
66 | /* This check proves that old 'sched' was installed */ |
67 | if (!cur_sched) |
68 | return; |
69 | |
70 | if (sched->done_service) |
71 | sched->done_service(svc); |
72 | /* svc->scheduler can be set to NULL only by caller */ |
73 | } |
74 | |
75 | |
76 | /* |
77 | * Get scheduler in the scheduler list by name |
78 | */ |
79 | static struct ip_vs_scheduler *ip_vs_sched_getbyname(const char *sched_name) |
80 | { |
81 | struct ip_vs_scheduler *sched; |
82 | |
83 | IP_VS_DBG(2, "%s(): sched_name \"%s\"\n" , __func__, sched_name); |
84 | |
85 | mutex_lock(&ip_vs_sched_mutex); |
86 | |
87 | list_for_each_entry(sched, &ip_vs_schedulers, n_list) { |
88 | /* |
89 | * Test and get the modules atomically |
90 | */ |
91 | if (sched->module && !try_module_get(module: sched->module)) { |
92 | /* |
93 | * This scheduler is just deleted |
94 | */ |
95 | continue; |
96 | } |
97 | if (strcmp(sched_name, sched->name)==0) { |
98 | /* HIT */ |
99 | mutex_unlock(lock: &ip_vs_sched_mutex); |
100 | return sched; |
101 | } |
102 | module_put(module: sched->module); |
103 | } |
104 | |
105 | mutex_unlock(lock: &ip_vs_sched_mutex); |
106 | return NULL; |
107 | } |
108 | |
109 | |
110 | /* |
111 | * Lookup scheduler and try to load it if it doesn't exist |
112 | */ |
113 | struct ip_vs_scheduler *ip_vs_scheduler_get(const char *sched_name) |
114 | { |
115 | struct ip_vs_scheduler *sched; |
116 | |
117 | /* |
118 | * Search for the scheduler by sched_name |
119 | */ |
120 | sched = ip_vs_sched_getbyname(sched_name); |
121 | |
122 | /* |
123 | * If scheduler not found, load the module and search again |
124 | */ |
125 | if (sched == NULL) { |
126 | request_module("ip_vs_%s" , sched_name); |
127 | sched = ip_vs_sched_getbyname(sched_name); |
128 | } |
129 | |
130 | return sched; |
131 | } |
132 | |
133 | void ip_vs_scheduler_put(struct ip_vs_scheduler *scheduler) |
134 | { |
135 | if (scheduler) |
136 | module_put(module: scheduler->module); |
137 | } |
138 | |
139 | /* |
140 | * Common error output helper for schedulers |
141 | */ |
142 | |
143 | void ip_vs_scheduler_err(struct ip_vs_service *svc, const char *msg) |
144 | { |
145 | struct ip_vs_scheduler *sched = rcu_dereference(svc->scheduler); |
146 | char *sched_name = sched ? sched->name : "none" ; |
147 | |
148 | if (svc->fwmark) { |
149 | IP_VS_ERR_RL("%s: FWM %u 0x%08X - %s\n" , |
150 | sched_name, svc->fwmark, svc->fwmark, msg); |
151 | #ifdef CONFIG_IP_VS_IPV6 |
152 | } else if (svc->af == AF_INET6) { |
153 | IP_VS_ERR_RL("%s: %s [%pI6c]:%d - %s\n" , |
154 | sched_name, ip_vs_proto_name(svc->protocol), |
155 | &svc->addr.in6, ntohs(svc->port), msg); |
156 | #endif |
157 | } else { |
158 | IP_VS_ERR_RL("%s: %s %pI4:%d - %s\n" , |
159 | sched_name, ip_vs_proto_name(svc->protocol), |
160 | &svc->addr.ip, ntohs(svc->port), msg); |
161 | } |
162 | } |
163 | |
164 | /* |
165 | * Register a scheduler in the scheduler list |
166 | */ |
167 | int register_ip_vs_scheduler(struct ip_vs_scheduler *scheduler) |
168 | { |
169 | struct ip_vs_scheduler *sched; |
170 | |
171 | if (!scheduler) { |
172 | pr_err("%s(): NULL arg\n" , __func__); |
173 | return -EINVAL; |
174 | } |
175 | |
176 | if (!scheduler->name) { |
177 | pr_err("%s(): NULL scheduler_name\n" , __func__); |
178 | return -EINVAL; |
179 | } |
180 | |
181 | /* increase the module use count */ |
182 | if (!ip_vs_use_count_inc()) |
183 | return -ENOENT; |
184 | |
185 | mutex_lock(&ip_vs_sched_mutex); |
186 | |
187 | if (!list_empty(head: &scheduler->n_list)) { |
188 | mutex_unlock(lock: &ip_vs_sched_mutex); |
189 | ip_vs_use_count_dec(); |
190 | pr_err("%s(): [%s] scheduler already linked\n" , |
191 | __func__, scheduler->name); |
192 | return -EINVAL; |
193 | } |
194 | |
195 | /* |
196 | * Make sure that the scheduler with this name doesn't exist |
197 | * in the scheduler list. |
198 | */ |
199 | list_for_each_entry(sched, &ip_vs_schedulers, n_list) { |
200 | if (strcmp(scheduler->name, sched->name) == 0) { |
201 | mutex_unlock(lock: &ip_vs_sched_mutex); |
202 | ip_vs_use_count_dec(); |
203 | pr_err("%s(): [%s] scheduler already existed " |
204 | "in the system\n" , __func__, scheduler->name); |
205 | return -EINVAL; |
206 | } |
207 | } |
208 | /* |
209 | * Add it into the d-linked scheduler list |
210 | */ |
211 | list_add(new: &scheduler->n_list, head: &ip_vs_schedulers); |
212 | mutex_unlock(lock: &ip_vs_sched_mutex); |
213 | |
214 | pr_info("[%s] scheduler registered.\n" , scheduler->name); |
215 | |
216 | return 0; |
217 | } |
218 | |
219 | |
220 | /* |
221 | * Unregister a scheduler from the scheduler list |
222 | */ |
223 | int unregister_ip_vs_scheduler(struct ip_vs_scheduler *scheduler) |
224 | { |
225 | if (!scheduler) { |
226 | pr_err("%s(): NULL arg\n" , __func__); |
227 | return -EINVAL; |
228 | } |
229 | |
230 | mutex_lock(&ip_vs_sched_mutex); |
231 | if (list_empty(head: &scheduler->n_list)) { |
232 | mutex_unlock(lock: &ip_vs_sched_mutex); |
233 | pr_err("%s(): [%s] scheduler is not in the list. failed\n" , |
234 | __func__, scheduler->name); |
235 | return -EINVAL; |
236 | } |
237 | |
238 | /* |
239 | * Remove it from the d-linked scheduler list |
240 | */ |
241 | list_del(entry: &scheduler->n_list); |
242 | mutex_unlock(lock: &ip_vs_sched_mutex); |
243 | |
244 | /* decrease the module use count */ |
245 | ip_vs_use_count_dec(); |
246 | |
247 | pr_info("[%s] scheduler unregistered.\n" , scheduler->name); |
248 | |
249 | return 0; |
250 | } |
251 | |