net/netfilter/ipvs/ip_vs_pe.c

   1 #define KMSG_COMPONENT "IPVS"
   2 #define pr_fmt(fmt) KMSG_COMPONENT ": " 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 */
  14 static LIST_HEAD(ip_vs_pe);
  15
  16 /* lock for service table */
  17 static DEFINE_SPINLOCK(ip_vs_pe_lock);
  18
  19 /* Bind a service with a pe */
  20 void ip_vs_bind_pe(struct ip_vs_service *svc, struct ip_vs_pe *pe)
  21 {
  22         svc->pe = pe;
  23 }
  24
  25 /* Unbind a service from its pe */
  26 void ip_vs_unbind_pe(struct ip_vs_service *svc)
  27 {
  28         svc->pe = NULL;
  29 }
  30
  31 /* Get pe in the pe list by name */
  32 struct ip_vs_pe *__ip_vs_pe_getbyname(const char *pe_name)
  33 {
  34         struct ip_vs_pe *pe;
  35
  36         IP_VS_DBG(10, "%s(): pe_name \"%s\"\n", __func__,
  37                   pe_name);
  38
  39         spin_lock_bh(&ip_vs_pe_lock);
  40
  41         list_for_each_entry(pe, &ip_vs_pe, n_list) {
  42                 /* Test and get the modules atomically */
  43                 if (pe->module &&
  44                     !try_module_get(pe->module)) {
  45                         /* This pe is just deleted */
  46                         continue;
  47                 }
  48                 if (strcmp(pe_name, pe->name)==0) {
  49                         /* HIT */
  50                         spin_unlock_bh(&ip_vs_pe_lock);
  51                         return pe;
  52                 }
  53                 if (pe->module)
  54                         module_put(pe->module);
  55         }
  56
  57         spin_unlock_bh(&ip_vs_pe_lock);
  58         return NULL;
  59 }
  60
  61 /* Lookup pe and try to load it if it doesn't exist */
  62 struct ip_vs_pe *ip_vs_pe_getbyname(const char *name)
  63 {
  64         struct ip_vs_pe *pe;
  65
  66         /* Search for the pe by name */
  67         pe = __ip_vs_pe_getbyname(name);
  68
  69         /* If pe not found, load the module and search again */
  70         if (!pe) {
  71                 request_module("ip_vs_pe_%s", name);
  72                 pe = __ip_vs_pe_getbyname(name);
  73         }
  74
  75         return pe;
  76 }
  77
  78 /* Register a pe in the pe list */
  79 int register_ip_vs_pe(struct ip_vs_pe *pe)
  80 {
  81         struct ip_vs_pe *tmp;
  82
  83         /* increase the module use count */
  84         ip_vs_use_count_inc();
  85
  86         spin_lock_bh(&ip_vs_pe_lock);
  87
  88         if (!list_empty(&pe->n_list)) {
  89                 spin_unlock_bh(&ip_vs_pe_lock);
  90                 ip_vs_use_count_dec();
  91                 pr_err("%s(): [%s] pe already linked\n",
  92                        __func__, pe->name);
  93                 return -EINVAL;
  94         }
  95
  96         /* Make sure that the pe with this name doesn't exist
  97          * in the pe list.
  98          */
  99         list_for_each_entry(tmp, &ip_vs_pe, n_list) {
 100                 if (strcmp(tmp->name, pe->name) == 0) {
 101                         spin_unlock_bh(&ip_vs_pe_lock);
 102                         ip_vs_use_count_dec();
 103                         pr_err("%s(): [%s] pe already existed "
 104                                "in the system\n", __func__, pe->name);
 105                         return -EINVAL;
 106                 }
 107         }
 108         /* Add it into the d-linked pe list */
 109         list_add(&pe->n_list, &ip_vs_pe);
 110         spin_unlock_bh(&ip_vs_pe_lock);
 111
 112         pr_info("[%s] pe registered.\n", pe->name);
 113
 114         return 0;
 115 }
 116 EXPORT_SYMBOL_GPL(register_ip_vs_pe);
 117
 118 /* Unregister a pe from the pe list */
 119 int unregister_ip_vs_pe(struct ip_vs_pe *pe)
 120 {
 121         spin_lock_bh(&ip_vs_pe_lock);
 122         if (list_empty(&pe->n_list)) {
 123                 spin_unlock_bh(&ip_vs_pe_lock);
 124                 pr_err("%s(): [%s] pe is not in the list. failed\n",
 125                        __func__, pe->name);
 126                 return -EINVAL;
 127         }
 128
 129         /* Remove it from the d-linked pe list */
 130         list_del(&pe->n_list);
 131         spin_unlock_bh(&ip_vs_pe_lock);
 132
 133         /* decrease the module use count */
 134         ip_vs_use_count_dec();
 135
 136         pr_info("[%s] pe unregistered.\n", pe->name);
 137
 138         return 0;
 139 }
 140 EXPORT_SYMBOL_GPL(unregister_ip_vs_pe);