net/netfilter/nf_conntrack_timestamp.c

   1 /*
   2  * (C) 2010 Pablo Neira Ayuso <pablo@netfilter.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation (or any later at your option).
   7  */
   8
   9 #include <linux/netfilter.h>
  10 #include <linux/slab.h>
  11 #include <linux/kernel.h>
  12 #include <linux/moduleparam.h>
  13
  14 #include <net/netfilter/nf_conntrack.h>
  15 #include <net/netfilter/nf_conntrack_extend.h>
  16 #include <net/netfilter/nf_conntrack_timestamp.h>
  17
  18 static bool nf_ct_tstamp __read_mostly;
  19
  20 module_param_named(tstamp, nf_ct_tstamp, bool, 0644);
  21 MODULE_PARM_DESC(tstamp, "Enable connection tracking flow timestamping.");
  22
  23 #ifdef CONFIG_SYSCTL
  24 static struct ctl_table tstamp_sysctl_table[] = {
  25         {
  26                 .procname       = "nf_conntrack_timestamp",
  27                 .data           = &init_net.ct.sysctl_tstamp,
  28                 .maxlen         = sizeof(unsigned int),
  29                 .mode           = 0644,
  30                 .proc_handler   = proc_dointvec,
  31         },
  32         {}
  33 };
  34 #endif /* CONFIG_SYSCTL */
  35
  36 static struct nf_ct_ext_type tstamp_extend __read_mostly = {
  37         .len    = sizeof(struct nf_conn_tstamp),
  38         .align  = __alignof__(struct nf_conn_tstamp),
  39         .id     = NF_CT_EXT_TSTAMP,
  40 };
  41
  42 #ifdef CONFIG_SYSCTL
  43 static int nf_conntrack_tstamp_init_sysctl(struct net *net)
  44 {
  45         struct ctl_table *table;
  46
  47         table = kmemdup(tstamp_sysctl_table, sizeof(tstamp_sysctl_table),
  48                         GFP_KERNEL);
  49         if (!table)
  50                 goto out;
  51
  52         table[0].data = &net->ct.sysctl_tstamp;
  53
  54         /* Don't export sysctls to unprivileged users */
  55         if (net->user_ns != &init_user_ns)
  56                 table[0].procname = NULL;
  57
  58         net->ct.tstamp_sysctl_header = register_net_sysctl(net, "net/netfilter",
  59                                                            table);
  60         if (!net->ct.tstamp_sysctl_header) {
  61                 printk(KERN_ERR "nf_ct_tstamp: can't register to sysctl.\n");
  62                 goto out_register;
  63         }
  64         return 0;
  65
  66 out_register:
  67         kfree(table);
  68 out:
  69         return -ENOMEM;
  70 }
  71
  72 static void nf_conntrack_tstamp_fini_sysctl(struct net *net)
  73 {
  74         struct ctl_table *table;
  75
  76         table = net->ct.tstamp_sysctl_header->ctl_table_arg;
  77         unregister_net_sysctl_table(net->ct.tstamp_sysctl_header);
  78         kfree(table);
  79 }
  80 #else
  81 static int nf_conntrack_tstamp_init_sysctl(struct net *net)
  82 {
  83         return 0;
  84 }
  85
  86 static void nf_conntrack_tstamp_fini_sysctl(struct net *net)
  87 {
  88 }
  89 #endif
  90
  91 int nf_conntrack_tstamp_pernet_init(struct net *net)
  92 {
  93         net->ct.sysctl_tstamp = nf_ct_tstamp;
  94         return nf_conntrack_tstamp_init_sysctl(net);
  95 }
  96
  97 void nf_conntrack_tstamp_pernet_fini(struct net *net)
  98 {
  99         nf_conntrack_tstamp_fini_sysctl(net);
 100         nf_ct_extend_unregister(&tstamp_extend);
 101 }
 102
 103 int nf_conntrack_tstamp_init(void)
 104 {
 105         int ret;
 106         ret = nf_ct_extend_register(&tstamp_extend);
 107         if (ret < 0)
 108                 pr_err("nf_ct_tstamp: Unable to register extension\n");
 109         return ret;
 110 }
 111
 112 void nf_conntrack_tstamp_fini(void)
 113 {
 114         nf_ct_extend_unregister(&tstamp_extend);
 115 }