1// SPDX-License-Identifier: GPL-2.0-only
2#define KMSG_COMPONENT "IPVS"
3#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
4
5#include <linux/module.h>
6#include <linux/spinlock.h>
7#include <linux/interrupt.h>
8#include <asm/string.h>
9#include <linux/kmod.h>
10#include <linux/sysctl.h>
11
12#include <net/ip_vs.h>
13
14/* IPVS pe list */
15static LIST_HEAD(ip_vs_pe);
16
17/* semaphore for IPVS PEs. */
18static DEFINE_MUTEX(ip_vs_pe_mutex);
19
20/* Get pe in the pe list by name */
21struct ip_vs_pe *__ip_vs_pe_getbyname(const char *pe_name)
22{
23	struct ip_vs_pe *pe;
24
25	IP_VS_DBG(10, "%s(): pe_name \"%s\"\n", __func__,
26		  pe_name);
27
28	rcu_read_lock();
29	list_for_each_entry_rcu(pe, &ip_vs_pe, n_list) {
30		/* Test and get the modules atomically */
31		if (pe->module &&
32		    !try_module_get(pe->module)) {
33			/* This pe is just deleted */
34			continue;
35		}
36		if (strcmp(pe_name, pe->name)==0) {
37			/* HIT */
38			rcu_read_unlock();
39			return pe;
40		}
41		module_put(pe->module);
42	}
43	rcu_read_unlock();
44
45	return NULL;
46}
47
48/* Lookup pe and try to load it if it doesn't exist */
49struct ip_vs_pe *ip_vs_pe_getbyname(const char *name)
50{
51	struct ip_vs_pe *pe;
52
53	/* Search for the pe by name */
54	pe = __ip_vs_pe_getbyname(name);
55
56	/* If pe not found, load the module and search again */
57	if (!pe) {
58		request_module("ip_vs_pe_%s", name);
59		pe = __ip_vs_pe_getbyname(name);
60	}
61
62	return pe;
63}
64
65/* Register a pe in the pe list */
66int register_ip_vs_pe(struct ip_vs_pe *pe)
67{
68	struct ip_vs_pe *tmp;
69
70	/* increase the module use count */
71	if (!ip_vs_use_count_inc())
72		return -ENOENT;
73
74	mutex_lock(&ip_vs_pe_mutex);
75	/* Make sure that the pe with this name doesn't exist
76	 * in the pe list.
77	 */
78	list_for_each_entry(tmp, &ip_vs_pe, n_list) {
79		if (strcmp(tmp->name, pe->name) == 0) {
80			mutex_unlock(&ip_vs_pe_mutex);
81			ip_vs_use_count_dec();
82			pr_err("%s(): [%s] pe already existed "
83			       "in the system\n", __func__, pe->name);
84			return -EINVAL;
85		}
86	}
87	/* Add it into the d-linked pe list */
88	list_add_rcu(&pe->n_list, &ip_vs_pe);
89	mutex_unlock(&ip_vs_pe_mutex);
90
91	pr_info("[%s] pe registered.\n", pe->name);
92
93	return 0;
94}
95EXPORT_SYMBOL_GPL(register_ip_vs_pe);
96
97/* Unregister a pe from the pe list */
98int unregister_ip_vs_pe(struct ip_vs_pe *pe)
99{
100	mutex_lock(&ip_vs_pe_mutex);
101	/* Remove it from the d-linked pe list */
102	list_del_rcu(&pe->n_list);
103	mutex_unlock(&ip_vs_pe_mutex);
104
105	/* decrease the module use count */
106	ip_vs_use_count_dec();
107
108	pr_info("[%s] pe unregistered.\n", pe->name);
109
110	return 0;
111}
112EXPORT_SYMBOL_GPL(unregister_ip_vs_pe);
113