1 /* 2 * 'raw' table, which is the very first hooked in at PRE_ROUTING and LOCAL_OUT . 3 * 4 * Copyright (C) 2003 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu> 5 */ 6 #include <linux/module.h> 7 #include <linux/netfilter_ipv4/ip_tables.h> 8 #include <linux/slab.h> 9 #include <net/ip.h> 10 11 #define RAW_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | (1 << NF_INET_LOCAL_OUT)) 12 13 static int __net_init iptable_raw_table_init(struct net *net); 14 15 static const struct xt_table packet_raw = { 16 .name = "raw", 17 .valid_hooks = RAW_VALID_HOOKS, 18 .me = THIS_MODULE, 19 .af = NFPROTO_IPV4, 20 .priority = NF_IP_PRI_RAW, 21 .table_init = iptable_raw_table_init, 22 }; 23 24 /* The work comes in here from netfilter.c. */ 25 static unsigned int 26 iptable_raw_hook(void *priv, struct sk_buff *skb, 27 const struct nf_hook_state *state) 28 { 29 if (state->hook == NF_INET_LOCAL_OUT && 30 (skb->len < sizeof(struct iphdr) || 31 ip_hdrlen(skb) < sizeof(struct iphdr))) 32 /* root is playing with raw sockets. */ 33 return NF_ACCEPT; 34 35 return ipt_do_table(skb, state, state->net->ipv4.iptable_raw); 36 } 37 38 static struct nf_hook_ops *rawtable_ops __read_mostly; 39 40 static int __net_init iptable_raw_table_init(struct net *net) 41 { 42 struct ipt_replace *repl; 43 int ret; 44 45 if (net->ipv4.iptable_raw) 46 return 0; 47 48 repl = ipt_alloc_initial_table(&packet_raw); 49 if (repl == NULL) 50 return -ENOMEM; 51 ret = ipt_register_table(net, &packet_raw, repl, rawtable_ops, 52 &net->ipv4.iptable_raw); 53 kfree(repl); 54 return ret; 55 } 56 57 static void __net_exit iptable_raw_net_exit(struct net *net) 58 { 59 if (!net->ipv4.iptable_raw) 60 return; 61 ipt_unregister_table(net, net->ipv4.iptable_raw, rawtable_ops); 62 net->ipv4.iptable_raw = NULL; 63 } 64 65 static struct pernet_operations iptable_raw_net_ops = { 66 .exit = iptable_raw_net_exit, 67 }; 68 69 static int __init iptable_raw_init(void) 70 { 71 int ret; 72 73 rawtable_ops = xt_hook_ops_alloc(&packet_raw, iptable_raw_hook); 74 if (IS_ERR(rawtable_ops)) 75 return PTR_ERR(rawtable_ops); 76 77 ret = register_pernet_subsys(&iptable_raw_net_ops); 78 if (ret < 0) { 79 kfree(rawtable_ops); 80 return ret; 81 } 82 83 ret = iptable_raw_table_init(&init_net); 84 if (ret) { 85 unregister_pernet_subsys(&iptable_raw_net_ops); 86 kfree(rawtable_ops); 87 } 88 89 return ret; 90 } 91 92 static void __exit iptable_raw_fini(void) 93 { 94 unregister_pernet_subsys(&iptable_raw_net_ops); 95 kfree(rawtable_ops); 96 } 97 98 module_init(iptable_raw_init); 99 module_exit(iptable_raw_fini); 100 MODULE_LICENSE("GPL"); 101