1// SPDX-License-Identifier: GPL-2.0-only
2#define pr_fmt(fmt) "IPVS: " fmt
3
4#include <linux/module.h>
5#include <linux/spinlock.h>
6#include <linux/interrupt.h>
7#include <asm/string.h>
8#include <linux/kmod.h>
9#include <linux/sysctl.h>
10
11#include <net/ip_vs.h>
12
13/* IPVS pe list */
14static LIST_HEAD(ip_vs_pe);
15
16/* semaphore for IPVS PEs. */
17static DEFINE_MUTEX(ip_vs_pe_mutex);
18
19/* Get pe in the pe list by name */
20struct ip_vs_pe *__ip_vs_pe_getbyname(const char *pe_name)
21{
22 struct ip_vs_pe *pe;
23
24 IP_VS_DBG(10, "%s(): pe_name \"%s\"\n", __func__,
25 pe_name);
26
27 rcu_read_lock();
28 list_for_each_entry_rcu(pe, &ip_vs_pe, n_list) {
29 /* Test and get the modules atomically */
30 if (pe->module &&
31 !try_module_get(module: pe->module)) {
32 /* This pe is just deleted */
33 continue;
34 }
35 if (strcmp(pe_name, pe->name)==0) {
36 /* HIT */
37 rcu_read_unlock();
38 return pe;
39 }
40 module_put(module: pe->module);
41 }
42 rcu_read_unlock();
43
44 return NULL;
45}
46
47/* Lookup pe and try to load it if it doesn't exist */
48struct ip_vs_pe *ip_vs_pe_getbyname(const char *name)
49{
50 struct ip_vs_pe *pe;
51
52 /* Search for the pe by name */
53 pe = __ip_vs_pe_getbyname(pe_name: name);
54
55 /* If pe not found, load the module and search again */
56 if (!pe) {
57 request_module("ip_vs_pe_%s", name);
58 pe = __ip_vs_pe_getbyname(pe_name: name);
59 }
60
61 return pe;
62}
63
64/* Register a pe in the pe list */
65int register_ip_vs_pe(struct ip_vs_pe *pe)
66{
67 struct ip_vs_pe *tmp;
68
69 /* increase the module use count */
70 if (!ip_vs_use_count_inc())
71 return -ENOENT;
72
73 mutex_lock(&ip_vs_pe_mutex);
74 /* Make sure that the pe with this name doesn't exist
75 * in the pe list.
76 */
77 list_for_each_entry(tmp, &ip_vs_pe, n_list) {
78 if (strcmp(tmp->name, pe->name) == 0) {
79 mutex_unlock(lock: &ip_vs_pe_mutex);
80 ip_vs_use_count_dec();
81 pr_err("%s(): [%s] pe already existed "
82 "in the system\n", __func__, pe->name);
83 return -EINVAL;
84 }
85 }
86 /* Add it into the d-linked pe list */
87 list_add_rcu(new: &pe->n_list, head: &ip_vs_pe);
88 mutex_unlock(lock: &ip_vs_pe_mutex);
89
90 pr_info("[%s] pe registered.\n", pe->name);
91
92 return 0;
93}
94EXPORT_SYMBOL_GPL(register_ip_vs_pe);
95
96/* Unregister a pe from the pe list */
97int unregister_ip_vs_pe(struct ip_vs_pe *pe)
98{
99 mutex_lock(&ip_vs_pe_mutex);
100 /* Remove it from the d-linked pe list */
101 list_del_rcu(entry: &pe->n_list);
102 mutex_unlock(lock: &ip_vs_pe_mutex);
103
104 /* decrease the module use count */
105 ip_vs_use_count_dec();
106
107 pr_info("[%s] pe unregistered.\n", pe->name);
108
109 return 0;
110}
111EXPORT_SYMBOL_GPL(unregister_ip_vs_pe);
112

source code of linux/net/netfilter/ipvs/ip_vs_pe.c