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xianfeng |
/*
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* IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6
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*
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* Copyright (C) 2000-2001 by Harald Welte <laforge@gnumonks.org>
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* Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/netfilter_ipv6/ip6_tables.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
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MODULE_DESCRIPTION("ip6tables mangle table");
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#define MANGLE_VALID_HOOKS ((1 << NF_IP6_PRE_ROUTING) | \
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(1 << NF_IP6_LOCAL_IN) | \
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(1 << NF_IP6_FORWARD) | \
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(1 << NF_IP6_LOCAL_OUT) | \
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(1 << NF_IP6_POST_ROUTING))
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static struct
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{
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struct ip6t_replace repl;
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struct ip6t_standard entries[5];
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struct ip6t_error term;
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} initial_table __initdata = {
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.repl = {
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.name = "mangle",
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.valid_hooks = MANGLE_VALID_HOOKS,
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.num_entries = 6,
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.size = sizeof(struct ip6t_standard) * 5 + sizeof(struct ip6t_error),
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.hook_entry = {
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[NF_IP6_PRE_ROUTING] = 0,
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[NF_IP6_LOCAL_IN] = sizeof(struct ip6t_standard),
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[NF_IP6_FORWARD] = sizeof(struct ip6t_standard) * 2,
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[NF_IP6_LOCAL_OUT] = sizeof(struct ip6t_standard) * 3,
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[NF_IP6_POST_ROUTING] = sizeof(struct ip6t_standard) * 4,
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},
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.underflow = {
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[NF_IP6_PRE_ROUTING] = 0,
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[NF_IP6_LOCAL_IN] = sizeof(struct ip6t_standard),
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[NF_IP6_FORWARD] = sizeof(struct ip6t_standard) * 2,
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[NF_IP6_LOCAL_OUT] = sizeof(struct ip6t_standard) * 3,
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[NF_IP6_POST_ROUTING] = sizeof(struct ip6t_standard) * 4,
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},
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},
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.entries = {
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IP6T_STANDARD_INIT(NF_ACCEPT), /* PRE_ROUTING */
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IP6T_STANDARD_INIT(NF_ACCEPT), /* LOCAL_IN */
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IP6T_STANDARD_INIT(NF_ACCEPT), /* FORWARD */
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IP6T_STANDARD_INIT(NF_ACCEPT), /* LOCAL_OUT */
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IP6T_STANDARD_INIT(NF_ACCEPT), /* POST_ROUTING */
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},
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.term = IP6T_ERROR_INIT, /* ERROR */
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};
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static struct xt_table packet_mangler = {
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.name = "mangle",
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.valid_hooks = MANGLE_VALID_HOOKS,
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.lock = RW_LOCK_UNLOCKED,
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.me = THIS_MODULE,
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.af = AF_INET6,
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};
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/* The work comes in here from netfilter.c. */
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static unsigned int
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ip6t_route_hook(unsigned int hook,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return ip6t_do_table(skb, hook, in, out, &packet_mangler);
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}
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static unsigned int
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ip6t_local_hook(unsigned int hook,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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unsigned int ret;
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struct in6_addr saddr, daddr;
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u_int8_t hop_limit;
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u_int32_t flowlabel, mark;
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#if 0
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/* root is playing with raw sockets. */
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if (skb->len < sizeof(struct iphdr)
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|| ip_hdrlen(skb) < sizeof(struct iphdr)) {
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if (net_ratelimit())
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printk("ip6t_hook: happy cracking.\n");
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return NF_ACCEPT;
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}
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#endif
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/* save source/dest address, mark, hoplimit, flowlabel, priority, */
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memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
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memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
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mark = skb->mark;
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hop_limit = ipv6_hdr(skb)->hop_limit;
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/* flowlabel and prio (includes version, which shouldn't change either */
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flowlabel = *((u_int32_t *)ipv6_hdr(skb));
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ret = ip6t_do_table(skb, hook, in, out, &packet_mangler);
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if (ret != NF_DROP && ret != NF_STOLEN
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&& (memcmp(&ipv6_hdr(skb)->saddr, &saddr, sizeof(saddr))
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|| memcmp(&ipv6_hdr(skb)->daddr, &daddr, sizeof(daddr))
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|| skb->mark != mark
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|| ipv6_hdr(skb)->hop_limit != hop_limit))
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return ip6_route_me_harder(skb) == 0 ? ret : NF_DROP;
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return ret;
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}
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static struct nf_hook_ops ip6t_ops[] = {
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{
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.hook = ip6t_route_hook,
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.owner = THIS_MODULE,
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.pf = PF_INET6,
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.hooknum = NF_IP6_PRE_ROUTING,
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.priority = NF_IP6_PRI_MANGLE,
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},
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{
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.hook = ip6t_local_hook,
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.owner = THIS_MODULE,
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.pf = PF_INET6,
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.hooknum = NF_IP6_LOCAL_IN,
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.priority = NF_IP6_PRI_MANGLE,
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},
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{
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.hook = ip6t_route_hook,
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.owner = THIS_MODULE,
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.pf = PF_INET6,
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.hooknum = NF_IP6_FORWARD,
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.priority = NF_IP6_PRI_MANGLE,
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},
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{
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.hook = ip6t_local_hook,
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.owner = THIS_MODULE,
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.pf = PF_INET6,
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.hooknum = NF_IP6_LOCAL_OUT,
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.priority = NF_IP6_PRI_MANGLE,
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},
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{
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.hook = ip6t_route_hook,
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.owner = THIS_MODULE,
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.pf = PF_INET6,
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.hooknum = NF_IP6_POST_ROUTING,
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.priority = NF_IP6_PRI_MANGLE,
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},
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};
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static int __init ip6table_mangle_init(void)
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{
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int ret;
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/* Register table */
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ret = ip6t_register_table(&packet_mangler, &initial_table.repl);
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if (ret < 0)
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return ret;
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/* Register hooks */
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ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
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if (ret < 0)
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goto cleanup_table;
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return ret;
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cleanup_table:
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ip6t_unregister_table(&packet_mangler);
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return ret;
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}
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static void __exit ip6table_mangle_fini(void)
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{
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nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
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ip6t_unregister_table(&packet_mangler);
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}
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module_init(ip6table_mangle_init);
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module_exit(ip6table_mangle_fini);
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