Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x. |
| 3 | * |
| 4 | * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling |
| 5 | * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org> |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License version 2 as |
| 9 | * published by the Free Software Foundation. |
| 10 | * |
| 11 | * Extended to all five netfilter hooks by Brad Chapman & Harald Welte |
| 12 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | #include <linux/module.h> |
| 14 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 15 | #include <linux/netdevice.h> |
| 16 | #include <linux/skbuff.h> |
| 17 | #include <net/sock.h> |
| 18 | #include <net/route.h> |
| 19 | #include <linux/ip.h> |
| 20 | |
| 21 | MODULE_LICENSE("GPL"); |
| 22 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); |
| 23 | MODULE_DESCRIPTION("iptables mangle table"); |
| 24 | |
| 25 | #define MANGLE_VALID_HOOKS ((1 << NF_IP_PRE_ROUTING) | \ |
| 26 | (1 << NF_IP_LOCAL_IN) | \ |
| 27 | (1 << NF_IP_FORWARD) | \ |
| 28 | (1 << NF_IP_LOCAL_OUT) | \ |
| 29 | (1 << NF_IP_POST_ROUTING)) |
| 30 | |
| 31 | /* Ouch - five different hooks? Maybe this should be a config option..... -- BC */ |
| 32 | static struct |
| 33 | { |
| 34 | struct ipt_replace repl; |
| 35 | struct ipt_standard entries[5]; |
| 36 | struct ipt_error term; |
| 37 | } initial_table __initdata |
| 38 | = { { "mangle", MANGLE_VALID_HOOKS, 6, |
| 39 | sizeof(struct ipt_standard) * 5 + sizeof(struct ipt_error), |
| 40 | { [NF_IP_PRE_ROUTING] = 0, |
| 41 | [NF_IP_LOCAL_IN] = sizeof(struct ipt_standard), |
| 42 | [NF_IP_FORWARD] = sizeof(struct ipt_standard) * 2, |
| 43 | [NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 3, |
| 44 | [NF_IP_POST_ROUTING] = sizeof(struct ipt_standard) * 4 }, |
| 45 | { [NF_IP_PRE_ROUTING] = 0, |
| 46 | [NF_IP_LOCAL_IN] = sizeof(struct ipt_standard), |
| 47 | [NF_IP_FORWARD] = sizeof(struct ipt_standard) * 2, |
| 48 | [NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 3, |
| 49 | [NF_IP_POST_ROUTING] = sizeof(struct ipt_standard) * 4 }, |
| 50 | 0, NULL, { } }, |
| 51 | { |
| 52 | /* PRE_ROUTING */ |
| 53 | { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 54 | 0, |
| 55 | sizeof(struct ipt_entry), |
| 56 | sizeof(struct ipt_standard), |
| 57 | 0, { 0, 0 }, { } }, |
| 58 | { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } }, |
| 59 | -NF_ACCEPT - 1 } }, |
| 60 | /* LOCAL_IN */ |
| 61 | { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 62 | 0, |
| 63 | sizeof(struct ipt_entry), |
| 64 | sizeof(struct ipt_standard), |
| 65 | 0, { 0, 0 }, { } }, |
| 66 | { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } }, |
| 67 | -NF_ACCEPT - 1 } }, |
| 68 | /* FORWARD */ |
| 69 | { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 70 | 0, |
| 71 | sizeof(struct ipt_entry), |
| 72 | sizeof(struct ipt_standard), |
| 73 | 0, { 0, 0 }, { } }, |
| 74 | { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } }, |
| 75 | -NF_ACCEPT - 1 } }, |
| 76 | /* LOCAL_OUT */ |
| 77 | { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 78 | 0, |
| 79 | sizeof(struct ipt_entry), |
| 80 | sizeof(struct ipt_standard), |
| 81 | 0, { 0, 0 }, { } }, |
| 82 | { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } }, |
| 83 | -NF_ACCEPT - 1 } }, |
| 84 | /* POST_ROUTING */ |
| 85 | { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 86 | 0, |
| 87 | sizeof(struct ipt_entry), |
| 88 | sizeof(struct ipt_standard), |
| 89 | 0, { 0, 0 }, { } }, |
| 90 | { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } }, |
| 91 | -NF_ACCEPT - 1 } }, |
| 92 | }, |
| 93 | /* ERROR */ |
| 94 | { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 95 | 0, |
| 96 | sizeof(struct ipt_entry), |
| 97 | sizeof(struct ipt_error), |
| 98 | 0, { 0, 0 }, { } }, |
| 99 | { { { { IPT_ALIGN(sizeof(struct ipt_error_target)), IPT_ERROR_TARGET } }, |
| 100 | { } }, |
| 101 | "ERROR" |
| 102 | } |
| 103 | } |
| 104 | }; |
| 105 | |
Jan Engelhardt | e60a13e | 2007-02-07 15:12:33 -0800 | [diff] [blame] | 106 | static struct xt_table packet_mangler = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | .name = "mangle", |
| 108 | .valid_hooks = MANGLE_VALID_HOOKS, |
| 109 | .lock = RW_LOCK_UNLOCKED, |
| 110 | .me = THIS_MODULE, |
Harald Welte | 2e4e6a1 | 2006-01-12 13:30:04 -0800 | [diff] [blame] | 111 | .af = AF_INET, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | }; |
| 113 | |
| 114 | /* The work comes in here from netfilter.c. */ |
| 115 | static unsigned int |
| 116 | ipt_route_hook(unsigned int hook, |
| 117 | struct sk_buff **pskb, |
| 118 | const struct net_device *in, |
| 119 | const struct net_device *out, |
| 120 | int (*okfn)(struct sk_buff *)) |
| 121 | { |
Patrick McHardy | fe1cb10 | 2006-08-22 00:35:47 -0700 | [diff] [blame] | 122 | return ipt_do_table(pskb, hook, in, out, &packet_mangler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | } |
| 124 | |
| 125 | static unsigned int |
| 126 | ipt_local_hook(unsigned int hook, |
| 127 | struct sk_buff **pskb, |
| 128 | const struct net_device *in, |
| 129 | const struct net_device *out, |
| 130 | int (*okfn)(struct sk_buff *)) |
| 131 | { |
| 132 | unsigned int ret; |
| 133 | u_int8_t tos; |
Al Viro | 6a19d61 | 2006-09-28 14:22:24 -0700 | [diff] [blame] | 134 | __be32 saddr, daddr; |
Thomas Graf | 82e91ff | 2006-11-09 15:19:14 -0800 | [diff] [blame] | 135 | u_int32_t mark; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | |
| 137 | /* root is playing with raw sockets. */ |
| 138 | if ((*pskb)->len < sizeof(struct iphdr) |
| 139 | || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) { |
| 140 | if (net_ratelimit()) |
| 141 | printk("ipt_hook: happy cracking.\n"); |
| 142 | return NF_ACCEPT; |
| 143 | } |
| 144 | |
| 145 | /* Save things which could affect route */ |
Thomas Graf | 82e91ff | 2006-11-09 15:19:14 -0800 | [diff] [blame] | 146 | mark = (*pskb)->mark; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | saddr = (*pskb)->nh.iph->saddr; |
| 148 | daddr = (*pskb)->nh.iph->daddr; |
| 149 | tos = (*pskb)->nh.iph->tos; |
| 150 | |
Patrick McHardy | fe1cb10 | 2006-08-22 00:35:47 -0700 | [diff] [blame] | 151 | ret = ipt_do_table(pskb, hook, in, out, &packet_mangler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | /* Reroute for ANY change. */ |
| 153 | if (ret != NF_DROP && ret != NF_STOLEN && ret != NF_QUEUE |
| 154 | && ((*pskb)->nh.iph->saddr != saddr |
| 155 | || (*pskb)->nh.iph->daddr != daddr |
Thomas Graf | 82e91ff | 2006-11-09 15:19:14 -0800 | [diff] [blame] | 156 | || (*pskb)->mark != mark |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | || (*pskb)->nh.iph->tos != tos)) |
Simon Horman | b4c4ed1 | 2006-10-02 16:11:13 -0700 | [diff] [blame] | 158 | if (ip_route_me_harder(pskb, RTN_UNSPEC)) |
| 159 | ret = NF_DROP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | |
| 161 | return ret; |
| 162 | } |
| 163 | |
| 164 | static struct nf_hook_ops ipt_ops[] = { |
| 165 | { |
| 166 | .hook = ipt_route_hook, |
| 167 | .owner = THIS_MODULE, |
| 168 | .pf = PF_INET, |
| 169 | .hooknum = NF_IP_PRE_ROUTING, |
| 170 | .priority = NF_IP_PRI_MANGLE, |
| 171 | }, |
| 172 | { |
| 173 | .hook = ipt_route_hook, |
| 174 | .owner = THIS_MODULE, |
| 175 | .pf = PF_INET, |
| 176 | .hooknum = NF_IP_LOCAL_IN, |
| 177 | .priority = NF_IP_PRI_MANGLE, |
| 178 | }, |
| 179 | { |
| 180 | .hook = ipt_route_hook, |
| 181 | .owner = THIS_MODULE, |
| 182 | .pf = PF_INET, |
| 183 | .hooknum = NF_IP_FORWARD, |
| 184 | .priority = NF_IP_PRI_MANGLE, |
| 185 | }, |
| 186 | { |
| 187 | .hook = ipt_local_hook, |
| 188 | .owner = THIS_MODULE, |
| 189 | .pf = PF_INET, |
| 190 | .hooknum = NF_IP_LOCAL_OUT, |
| 191 | .priority = NF_IP_PRI_MANGLE, |
| 192 | }, |
| 193 | { |
| 194 | .hook = ipt_route_hook, |
| 195 | .owner = THIS_MODULE, |
| 196 | .pf = PF_INET, |
| 197 | .hooknum = NF_IP_POST_ROUTING, |
| 198 | .priority = NF_IP_PRI_MANGLE, |
| 199 | }, |
| 200 | }; |
| 201 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 202 | static int __init iptable_mangle_init(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | { |
| 204 | int ret; |
| 205 | |
| 206 | /* Register table */ |
| 207 | ret = ipt_register_table(&packet_mangler, &initial_table.repl); |
| 208 | if (ret < 0) |
| 209 | return ret; |
| 210 | |
| 211 | /* Register hooks */ |
Patrick McHardy | 964ddaa | 2006-04-06 14:09:49 -0700 | [diff] [blame] | 212 | ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 213 | if (ret < 0) |
| 214 | goto cleanup_table; |
| 215 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | return ret; |
| 217 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | cleanup_table: |
| 219 | ipt_unregister_table(&packet_mangler); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | return ret; |
| 221 | } |
| 222 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 223 | static void __exit iptable_mangle_fini(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 224 | { |
Patrick McHardy | 964ddaa | 2006-04-06 14:09:49 -0700 | [diff] [blame] | 225 | nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 226 | ipt_unregister_table(&packet_mangler); |
| 227 | } |
| 228 | |
Andrew Morton | 65b4b4e | 2006-03-28 16:37:06 -0800 | [diff] [blame] | 229 | module_init(iptable_mangle_init); |
| 230 | module_exit(iptable_mangle_fini); |