net/netfilter/nf_conntrack_timeout.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
   4  * (C) 2012 by Vyatta Inc. <http://www.vyatta.com>
   5  */
   6
   7 #include <linux/types.h>
   8 #include <linux/netfilter.h>
   9 #include <linux/skbuff.h>
  10 #include <linux/vmalloc.h>
  11 #include <linux/stddef.h>
  12 #include <linux/err.h>
  13 #include <linux/percpu.h>
  14 #include <linux/kernel.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/slab.h>
  17 #include <linux/export.h>
  18
  19 #include <net/netfilter/nf_conntrack.h>
  20 #include <net/netfilter/nf_conntrack_core.h>
  21 #include <net/netfilter/nf_conntrack_extend.h>
  22 #include <net/netfilter/nf_conntrack_l4proto.h>
  23 #include <net/netfilter/nf_conntrack_timeout.h>
  24
  25 const struct nf_ct_timeout_hooks *nf_ct_timeout_hook __read_mostly;
  26 EXPORT_SYMBOL_GPL(nf_ct_timeout_hook);
  27
  28 static int untimeout(struct nf_conn *ct, void *timeout)
  29 {
  30         struct nf_conn_timeout *timeout_ext = nf_ct_timeout_find(ct);
  31
  32         if (timeout_ext && (!timeout || timeout_ext->timeout == timeout))
  33                 RCU_INIT_POINTER(timeout_ext->timeout, NULL);
  34
  35         /* We are not intended to delete this conntrack. */
  36         return 0;
  37 }
  38
  39 void nf_ct_untimeout(struct net *net, struct nf_ct_timeout *timeout)
  40 {
  41         nf_ct_iterate_cleanup_net(net, untimeout, timeout, 0, 0);
  42 }
  43 EXPORT_SYMBOL_GPL(nf_ct_untimeout);
  44
  45 static void __nf_ct_timeout_put(struct nf_ct_timeout *timeout)
  46 {
  47         const struct nf_ct_timeout_hooks *h = rcu_dereference(nf_ct_timeout_hook);
  48
  49         if (h)
  50                 h->timeout_put(timeout);
  51 }
  52
  53 int nf_ct_set_timeout(struct net *net, struct nf_conn *ct,
  54                       u8 l3num, u8 l4num, const char *timeout_name)
  55 {
  56         const struct nf_ct_timeout_hooks *h;
  57         struct nf_ct_timeout *timeout;
  58         struct nf_conn_timeout *timeout_ext;
  59         const char *errmsg = NULL;
  60         int ret = 0;
  61
  62         rcu_read_lock();
  63         h = rcu_dereference(nf_ct_timeout_hook);
  64         if (!h) {
  65                 ret = -ENOENT;
  66                 errmsg = "Timeout policy base is empty";
  67                 goto out;
  68         }
  69
  70         timeout = h->timeout_find_get(net, timeout_name);
  71         if (!timeout) {
  72                 ret = -ENOENT;
  73                 pr_info_ratelimited("No such timeout policy \"%s\"\n",
  74                                     timeout_name);
  75                 goto out;
  76         }
  77
  78         if (timeout->l3num != l3num) {
  79                 ret = -EINVAL;
  80                 pr_info_ratelimited("Timeout policy `%s' can only be used by "
  81                                     "L%d protocol number %d\n",
  82                                     timeout_name, 3, timeout->l3num);
  83                 goto err_put_timeout;
  84         }
  85         /* Make sure the timeout policy matches any existing protocol tracker,
  86          * otherwise default to generic.
  87          */
  88         if (timeout->l4proto->l4proto != l4num) {
  89                 ret = -EINVAL;
  90                 pr_info_ratelimited("Timeout policy `%s' can only be used by "
  91                                     "L%d protocol number %d\n",
  92                                     timeout_name, 4, timeout->l4proto->l4proto);
  93                 goto err_put_timeout;
  94         }
  95         timeout_ext = nf_ct_timeout_ext_add(ct, timeout, GFP_ATOMIC);
  96         if (!timeout_ext) {
  97                 ret = -ENOMEM;
  98                 goto err_put_timeout;
  99         }
 100
 101         rcu_read_unlock();
 102         return ret;
 103
 104 err_put_timeout:
 105         __nf_ct_timeout_put(timeout);
 106 out:
 107         rcu_read_unlock();
 108         if (errmsg)
 109                 pr_info_ratelimited("%s\n", errmsg);
 110         return ret;
 111 }
 112 EXPORT_SYMBOL_GPL(nf_ct_set_timeout);
 113
 114 void nf_ct_destroy_timeout(struct nf_conn *ct)
 115 {
 116         struct nf_conn_timeout *timeout_ext;
 117         const struct nf_ct_timeout_hooks *h;
 118
 119         rcu_read_lock();
 120         h = rcu_dereference(nf_ct_timeout_hook);
 121
 122         if (h) {
 123                 timeout_ext = nf_ct_timeout_find(ct);
 124                 if (timeout_ext) {
 125                         h->timeout_put(timeout_ext->timeout);
 126                         RCU_INIT_POINTER(timeout_ext->timeout, NULL);
 127                 }
 128         }
 129         rcu_read_unlock();
 130 }
 131 EXPORT_SYMBOL_GPL(nf_ct_destroy_timeout);