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         net->ct.tstamp_sysctl_header = register_net_sysctl_table(net,
  55                         nf_net_netfilter_sysctl_path, table);
  56         if (!net->ct.tstamp_sysctl_header) {
  57                 printk(KERN_ERR "nf_ct_tstamp: can't register to sysctl.\n");
  58                 goto out_register;
  59         }
  60         return 0;
  61
  62 out_register:
  63         kfree(table);
  64 out:
  65         return -ENOMEM;
  66 }
  67
  68 static void nf_conntrack_tstamp_fini_sysctl(struct net *net)
  69 {
  70         struct ctl_table *table;
  71
  72         table = net->ct.tstamp_sysctl_header->ctl_table_arg;
  73         unregister_net_sysctl_table(net->ct.tstamp_sysctl_header);
  74         kfree(table);
  75 }
  76 #else
  77 static int nf_conntrack_tstamp_init_sysctl(struct net *net)
  78 {
  79         return 0;
  80 }
  81
  82 static void nf_conntrack_tstamp_fini_sysctl(struct net *net)
  83 {
  84 }
  85 #endif
  86
  87 int nf_conntrack_tstamp_init(struct net *net)
  88 {
  89         int ret;
  90
  91         net->ct.sysctl_tstamp = nf_ct_tstamp;
  92
  93         if (net_eq(net, &init_net)) {
  94                 ret = nf_ct_extend_register(&tstamp_extend);
  95                 if (ret < 0) {
  96                         printk(KERN_ERR "nf_ct_tstamp: Unable to register "
  97                                         "extension\n");
  98                         goto out_extend_register;
  99                 }
 100         }
 101
 102         ret = nf_conntrack_tstamp_init_sysctl(net);
 103         if (ret < 0)
 104                 goto out_sysctl;
 105
 106         return 0;
 107
 108 out_sysctl:
 109         if (net_eq(net, &init_net))
 110                 nf_ct_extend_unregister(&tstamp_extend);
 111 out_extend_register:
 112         return ret;
 113 }
 114
 115 void nf_conntrack_tstamp_fini(struct net *net)
 116 {
 117         nf_conntrack_tstamp_fini_sysctl(net);
 118         if (net_eq(net, &init_net))
 119                 nf_ct_extend_unregister(&tstamp_extend);
 120 }