root/net/ipv4/netfilter/iptable_raw.c

DEFINITIONS

1. iptable_raw_hook
2. iptable_raw_table_init
3. iptable_raw_net_exit
4. iptable_raw_init
5. iptable_raw_fini

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * 'raw' table, which is the very first hooked in at PRE_ROUTING and LOCAL_OUT .
   4  *
   5  * Copyright (C) 2003 Jozsef Kadlecsik <kadlec@netfilter.org>
   6  */
   7 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   8 #include <linux/module.h>
   9 #include <linux/netfilter_ipv4/ip_tables.h>
  10 #include <linux/slab.h>
  11 #include <net/ip.h>
  12 
  13 #define RAW_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT))
  14 
  15 static int __net_init iptable_raw_table_init(struct net *net);
  16 
  17 static bool raw_before_defrag __read_mostly;
  18 MODULE_PARM_DESC(raw_before_defrag, "Enable raw table before defrag");
  19 module_param(raw_before_defrag, bool, 0000);
  20 
  21 static const struct xt_table packet_raw = {
  22         .name = "raw",
  23         .valid_hooks =  RAW_VALID_HOOKS,
  24         .me = THIS_MODULE,
  25         .af = NFPROTO_IPV4,
  26         .priority = NF_IP_PRI_RAW,
  27         .table_init = iptable_raw_table_init,
  28 };
  29 
  30 static const struct xt_table packet_raw_before_defrag = {
  31         .name = "raw",
  32         .valid_hooks =  RAW_VALID_HOOKS,
  33         .me = THIS_MODULE,
  34         .af = NFPROTO_IPV4,
  35         .priority = NF_IP_PRI_RAW_BEFORE_DEFRAG,
  36         .table_init = iptable_raw_table_init,
  37 };
  38 
  39 /* The work comes in here from netfilter.c. */
  40 static unsigned int
  41 iptable_raw_hook(void *priv, struct sk_buff *skb,
  42                  const struct nf_hook_state *state)
  43 {
  44         return ipt_do_table(skb, state, state->net->ipv4.iptable_raw);
  45 }
  46 
  47 static struct nf_hook_ops *rawtable_ops __read_mostly;
  48 
  49 static int __net_init iptable_raw_table_init(struct net *net)
  50 {
  51         struct ipt_replace *repl;
  52         const struct xt_table *table = &packet_raw;
  53         int ret;
  54 
  55         if (raw_before_defrag)
  56                 table = &packet_raw_before_defrag;
  57 
  58         if (net->ipv4.iptable_raw)
  59                 return 0;
  60 
  61         repl = ipt_alloc_initial_table(table);
  62         if (repl == NULL)
  63                 return -ENOMEM;
  64         ret = ipt_register_table(net, table, repl, rawtable_ops,
  65                                  &net->ipv4.iptable_raw);
  66         kfree(repl);
  67         return ret;
  68 }
  69 
  70 static void __net_exit iptable_raw_net_exit(struct net *net)
  71 {
  72         if (!net->ipv4.iptable_raw)
  73                 return;
  74         ipt_unregister_table(net, net->ipv4.iptable_raw, rawtable_ops);
  75         net->ipv4.iptable_raw = NULL;
  76 }
  77 
  78 static struct pernet_operations iptable_raw_net_ops = {
  79         .exit = iptable_raw_net_exit,
  80 };
  81 
  82 static int __init iptable_raw_init(void)
  83 {
  84         int ret;
  85         const struct xt_table *table = &packet_raw;
  86 
  87         if (raw_before_defrag) {
  88                 table = &packet_raw_before_defrag;
  89 
  90                 pr_info("Enabling raw table before defrag\n");
  91         }
  92 
  93         rawtable_ops = xt_hook_ops_alloc(table, iptable_raw_hook);
  94         if (IS_ERR(rawtable_ops))
  95                 return PTR_ERR(rawtable_ops);
  96 
  97         ret = register_pernet_subsys(&iptable_raw_net_ops);
  98         if (ret < 0) {
  99                 kfree(rawtable_ops);
 100                 return ret;
 101         }
 102 
 103         ret = iptable_raw_table_init(&init_net);
 104         if (ret) {
 105                 unregister_pernet_subsys(&iptable_raw_net_ops);
 106                 kfree(rawtable_ops);
 107         }
 108 
 109         return ret;
 110 }
 111 
 112 static void __exit iptable_raw_fini(void)
 113 {
 114         unregister_pernet_subsys(&iptable_raw_net_ops);
 115         kfree(rawtable_ops);
 116 }
 117 
 118 module_init(iptable_raw_init);
 119 module_exit(iptable_raw_fini);
 120 MODULE_LICENSE("GPL");