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- /*
- * IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6
- *
- * Copyright (C) 2000-2001 by Harald Welte <laforge@gnumonks.org>
- * 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.
- */
- #include <linux/module.h>
- #include <linux/netfilter_ipv6/ip6_tables.h>
- #include <linux/slab.h>
- #include <net/ipv6.h>
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
- MODULE_DESCRIPTION("ip6tables mangle table");
- #define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \
- (1 << NF_INET_LOCAL_IN) | \
- (1 << NF_INET_FORWARD) | \
- (1 << NF_INET_LOCAL_OUT) | \
- (1 << NF_INET_POST_ROUTING))
- static const struct xt_table packet_mangler = {
- .name = "mangle",
- .valid_hooks = MANGLE_VALID_HOOKS,
- .me = THIS_MODULE,
- .af = NFPROTO_IPV6,
- .priority = NF_IP6_PRI_MANGLE,
- };
- static unsigned int
- ip6t_mangle_out(struct sk_buff *skb, const struct nf_hook_state *state)
- {
- unsigned int ret;
- struct in6_addr saddr, daddr;
- u_int8_t hop_limit;
- u_int32_t flowlabel, mark;
- int err;
- #if 0
- /* root is playing with raw sockets. */
- if (skb->len < sizeof(struct iphdr) ||
- ip_hdrlen(skb) < sizeof(struct iphdr)) {
- net_warn_ratelimited("ip6t_hook: happy cracking\n");
- return NF_ACCEPT;
- }
- #endif
- /* save source/dest address, mark, hoplimit, flowlabel, priority, */
- memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
- memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
- mark = skb->mark;
- hop_limit = ipv6_hdr(skb)->hop_limit;
- /* flowlabel and prio (includes version, which shouldn't change either */
- flowlabel = *((u_int32_t *)ipv6_hdr(skb));
- ret = ip6t_do_table(skb, state, state->net->ipv6.ip6table_mangle);
- if (ret != NF_DROP && ret != NF_STOLEN &&
- (!ipv6_addr_equal(&ipv6_hdr(skb)->saddr, &saddr) ||
- !ipv6_addr_equal(&ipv6_hdr(skb)->daddr, &daddr) ||
- skb->mark != mark ||
- ipv6_hdr(skb)->hop_limit != hop_limit ||
- flowlabel != *((u_int32_t *)ipv6_hdr(skb)))) {
- err = ip6_route_me_harder(state->net, skb);
- if (err < 0)
- ret = NF_DROP_ERR(err);
- }
- return ret;
- }
- /* The work comes in here from netfilter.c. */
- static unsigned int
- ip6table_mangle_hook(void *priv, struct sk_buff *skb,
- const struct nf_hook_state *state)
- {
- if (state->hook == NF_INET_LOCAL_OUT)
- return ip6t_mangle_out(skb, state);
- if (state->hook == NF_INET_POST_ROUTING)
- return ip6t_do_table(skb, state,
- state->net->ipv6.ip6table_mangle);
- /* INPUT/FORWARD */
- return ip6t_do_table(skb, state, state->net->ipv6.ip6table_mangle);
- }
- static struct nf_hook_ops *mangle_ops __read_mostly;
- static int __net_init ip6table_mangle_net_init(struct net *net)
- {
- struct ip6t_replace *repl;
- repl = ip6t_alloc_initial_table(&packet_mangler);
- if (repl == NULL)
- return -ENOMEM;
- net->ipv6.ip6table_mangle =
- ip6t_register_table(net, &packet_mangler, repl);
- kfree(repl);
- return PTR_ERR_OR_ZERO(net->ipv6.ip6table_mangle);
- }
- static void __net_exit ip6table_mangle_net_exit(struct net *net)
- {
- ip6t_unregister_table(net, net->ipv6.ip6table_mangle);
- }
- static struct pernet_operations ip6table_mangle_net_ops = {
- .init = ip6table_mangle_net_init,
- .exit = ip6table_mangle_net_exit,
- };
- static int __init ip6table_mangle_init(void)
- {
- int ret;
- ret = register_pernet_subsys(&ip6table_mangle_net_ops);
- if (ret < 0)
- return ret;
- /* Register hooks */
- mangle_ops = xt_hook_link(&packet_mangler, ip6table_mangle_hook);
- if (IS_ERR(mangle_ops)) {
- ret = PTR_ERR(mangle_ops);
- goto cleanup_table;
- }
- return ret;
- cleanup_table:
- unregister_pernet_subsys(&ip6table_mangle_net_ops);
- return ret;
- }
- static void __exit ip6table_mangle_fini(void)
- {
- xt_hook_unlink(&packet_mangler, mangle_ops);
- unregister_pernet_subsys(&ip6table_mangle_net_ops);
- }
- module_init(ip6table_mangle_init);
- module_exit(ip6table_mangle_fini);
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