| /* |
| * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x. |
| * |
| * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling |
| * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * Extended to all five netfilter hooks by Brad Chapman & Harald Welte |
| */ |
| #include <linux/module.h> |
| #include <linux/netfilter_ipv4/ip_tables.h> |
| #include <linux/netdevice.h> |
| #include <linux/skbuff.h> |
| #include <net/sock.h> |
| #include <net/route.h> |
| #include <linux/ip.h> |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); |
| MODULE_DESCRIPTION("iptables mangle table"); |
| |
| #define MANGLE_VALID_HOOKS ((1 << NF_IP_PRE_ROUTING) | \ |
| (1 << NF_IP_LOCAL_IN) | \ |
| (1 << NF_IP_FORWARD) | \ |
| (1 << NF_IP_LOCAL_OUT) | \ |
| (1 << NF_IP_POST_ROUTING)) |
| |
| /* Ouch - five different hooks? Maybe this should be a config option..... -- BC */ |
| static struct |
| { |
| struct ipt_replace repl; |
| struct ipt_standard entries[5]; |
| struct ipt_error term; |
| } initial_table __initdata |
| = { { "mangle", MANGLE_VALID_HOOKS, 6, |
| sizeof(struct ipt_standard) * 5 + sizeof(struct ipt_error), |
| { [NF_IP_PRE_ROUTING] = 0, |
| [NF_IP_LOCAL_IN] = sizeof(struct ipt_standard), |
| [NF_IP_FORWARD] = sizeof(struct ipt_standard) * 2, |
| [NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 3, |
| [NF_IP_POST_ROUTING] = sizeof(struct ipt_standard) * 4 }, |
| { [NF_IP_PRE_ROUTING] = 0, |
| [NF_IP_LOCAL_IN] = sizeof(struct ipt_standard), |
| [NF_IP_FORWARD] = sizeof(struct ipt_standard) * 2, |
| [NF_IP_LOCAL_OUT] = sizeof(struct ipt_standard) * 3, |
| [NF_IP_POST_ROUTING] = sizeof(struct ipt_standard) * 4 }, |
| 0, NULL, { } }, |
| { |
| /* PRE_ROUTING */ |
| { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 0, |
| sizeof(struct ipt_entry), |
| sizeof(struct ipt_standard), |
| 0, { 0, 0 }, { } }, |
| { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } }, |
| -NF_ACCEPT - 1 } }, |
| /* LOCAL_IN */ |
| { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 0, |
| sizeof(struct ipt_entry), |
| sizeof(struct ipt_standard), |
| 0, { 0, 0 }, { } }, |
| { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } }, |
| -NF_ACCEPT - 1 } }, |
| /* FORWARD */ |
| { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 0, |
| sizeof(struct ipt_entry), |
| sizeof(struct ipt_standard), |
| 0, { 0, 0 }, { } }, |
| { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } }, |
| -NF_ACCEPT - 1 } }, |
| /* LOCAL_OUT */ |
| { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 0, |
| sizeof(struct ipt_entry), |
| sizeof(struct ipt_standard), |
| 0, { 0, 0 }, { } }, |
| { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } }, |
| -NF_ACCEPT - 1 } }, |
| /* POST_ROUTING */ |
| { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 0, |
| sizeof(struct ipt_entry), |
| sizeof(struct ipt_standard), |
| 0, { 0, 0 }, { } }, |
| { { { { IPT_ALIGN(sizeof(struct ipt_standard_target)), "" } }, { } }, |
| -NF_ACCEPT - 1 } }, |
| }, |
| /* ERROR */ |
| { { { { 0 }, { 0 }, { 0 }, { 0 }, "", "", { 0 }, { 0 }, 0, 0, 0 }, |
| 0, |
| sizeof(struct ipt_entry), |
| sizeof(struct ipt_error), |
| 0, { 0, 0 }, { } }, |
| { { { { IPT_ALIGN(sizeof(struct ipt_error_target)), IPT_ERROR_TARGET } }, |
| { } }, |
| "ERROR" |
| } |
| } |
| }; |
| |
| static struct ipt_table packet_mangler = { |
| .name = "mangle", |
| .valid_hooks = MANGLE_VALID_HOOKS, |
| .lock = RW_LOCK_UNLOCKED, |
| .me = THIS_MODULE, |
| .af = AF_INET, |
| }; |
| |
| /* The work comes in here from netfilter.c. */ |
| static unsigned int |
| ipt_route_hook(unsigned int hook, |
| struct sk_buff **pskb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| return ipt_do_table(pskb, hook, in, out, &packet_mangler); |
| } |
| |
| static unsigned int |
| ipt_local_hook(unsigned int hook, |
| struct sk_buff **pskb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| unsigned int ret; |
| u_int8_t tos; |
| __be32 saddr, daddr; |
| u_int32_t mark; |
| |
| /* root is playing with raw sockets. */ |
| if ((*pskb)->len < sizeof(struct iphdr) |
| || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) { |
| if (net_ratelimit()) |
| printk("ipt_hook: happy cracking.\n"); |
| return NF_ACCEPT; |
| } |
| |
| /* Save things which could affect route */ |
| mark = (*pskb)->mark; |
| saddr = (*pskb)->nh.iph->saddr; |
| daddr = (*pskb)->nh.iph->daddr; |
| tos = (*pskb)->nh.iph->tos; |
| |
| ret = ipt_do_table(pskb, hook, in, out, &packet_mangler); |
| /* Reroute for ANY change. */ |
| if (ret != NF_DROP && ret != NF_STOLEN && ret != NF_QUEUE |
| && ((*pskb)->nh.iph->saddr != saddr |
| || (*pskb)->nh.iph->daddr != daddr |
| || (*pskb)->mark != mark |
| || (*pskb)->nh.iph->tos != tos)) |
| if (ip_route_me_harder(pskb, RTN_UNSPEC)) |
| ret = NF_DROP; |
| |
| return ret; |
| } |
| |
| static struct nf_hook_ops ipt_ops[] = { |
| { |
| .hook = ipt_route_hook, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_PRE_ROUTING, |
| .priority = NF_IP_PRI_MANGLE, |
| }, |
| { |
| .hook = ipt_route_hook, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_LOCAL_IN, |
| .priority = NF_IP_PRI_MANGLE, |
| }, |
| { |
| .hook = ipt_route_hook, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_FORWARD, |
| .priority = NF_IP_PRI_MANGLE, |
| }, |
| { |
| .hook = ipt_local_hook, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_LOCAL_OUT, |
| .priority = NF_IP_PRI_MANGLE, |
| }, |
| { |
| .hook = ipt_route_hook, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_POST_ROUTING, |
| .priority = NF_IP_PRI_MANGLE, |
| }, |
| }; |
| |
| static int __init iptable_mangle_init(void) |
| { |
| int ret; |
| |
| /* Register table */ |
| ret = ipt_register_table(&packet_mangler, &initial_table.repl); |
| if (ret < 0) |
| return ret; |
| |
| /* Register hooks */ |
| ret = nf_register_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); |
| if (ret < 0) |
| goto cleanup_table; |
| |
| return ret; |
| |
| cleanup_table: |
| ipt_unregister_table(&packet_mangler); |
| return ret; |
| } |
| |
| static void __exit iptable_mangle_fini(void) |
| { |
| nf_unregister_hooks(ipt_ops, ARRAY_SIZE(ipt_ops)); |
| ipt_unregister_table(&packet_mangler); |
| } |
| |
| module_init(iptable_mangle_init); |
| module_exit(iptable_mangle_fini); |