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 */
15 static LIST_HEAD(ip_vs_pe);
16 
17 /* semaphore for IPVS PEs. */
18 static DEFINE_MUTEX(ip_vs_pe_mutex);
19 
20 /* Get pe in the pe list by name */
__ip_vs_pe_getbyname(const char * pe_name)21 struct 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 */
ip_vs_pe_getbyname(const char * name)49 struct 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 */
register_ip_vs_pe(struct ip_vs_pe * pe)66 int 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 }
95 EXPORT_SYMBOL_GPL(register_ip_vs_pe);
96 
97 /* Unregister a pe from the pe list */
unregister_ip_vs_pe(struct ip_vs_pe * pe)98 int 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 }
112 EXPORT_SYMBOL_GPL(unregister_ip_vs_pe);
113