// SPDX-License-Identifier: GPL-2.0-only
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/*
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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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#include <linux/module.h>
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#include <linux/netfilter_ipv6/ip6_tables.h>
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#include <linux/slab.h>
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#include <net/ipv6.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_INET_PRE_ROUTING) | \
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(1 << NF_INET_LOCAL_IN) | \
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(1 << NF_INET_FORWARD) | \
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(1 << NF_INET_LOCAL_OUT) | \
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(1 << NF_INET_POST_ROUTING))
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static int __net_init ip6table_mangle_table_init(struct net *net);
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static const struct xt_table packet_mangler = {
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.name = "mangle",
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.valid_hooks = MANGLE_VALID_HOOKS,
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.me = THIS_MODULE,
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.af = NFPROTO_IPV6,
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.priority = NF_IP6_PRI_MANGLE,
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.table_init = ip6table_mangle_table_init,
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};
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static unsigned int
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ip6t_mangle_out(struct sk_buff *skb, const struct nf_hook_state *state)
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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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int err;
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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, state, state->net->ipv6.ip6table_mangle);
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if (ret != NF_DROP && ret != NF_STOLEN &&
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(!ipv6_addr_equal(&ipv6_hdr(skb)->saddr, &saddr) ||
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!ipv6_addr_equal(&ipv6_hdr(skb)->daddr, &daddr) ||
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skb->mark != mark ||
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ipv6_hdr(skb)->hop_limit != hop_limit ||
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flowlabel != *((u_int32_t *)ipv6_hdr(skb)))) {
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err = ip6_route_me_harder(state->net, state->sk, skb);
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if (err < 0)
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ret = NF_DROP_ERR(err);
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}
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return ret;
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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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ip6table_mangle_hook(void *priv, struct sk_buff *skb,
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const struct nf_hook_state *state)
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{
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if (state->hook == NF_INET_LOCAL_OUT)
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return ip6t_mangle_out(skb, state);
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return ip6t_do_table(skb, state, state->net->ipv6.ip6table_mangle);
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}
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static struct nf_hook_ops *mangle_ops __read_mostly;
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static int __net_init ip6table_mangle_table_init(struct net *net)
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{
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struct ip6t_replace *repl;
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int ret;
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if (net->ipv6.ip6table_mangle)
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return 0;
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repl = ip6t_alloc_initial_table(&packet_mangler);
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if (repl == NULL)
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return -ENOMEM;
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ret = ip6t_register_table(net, &packet_mangler, repl, mangle_ops,
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&net->ipv6.ip6table_mangle);
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kfree(repl);
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return ret;
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}
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static void __net_exit ip6table_mangle_net_pre_exit(struct net *net)
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{
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if (net->ipv6.ip6table_mangle)
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ip6t_unregister_table_pre_exit(net, net->ipv6.ip6table_mangle,
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mangle_ops);
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}
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static void __net_exit ip6table_mangle_net_exit(struct net *net)
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{
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if (!net->ipv6.ip6table_mangle)
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return;
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ip6t_unregister_table_exit(net, net->ipv6.ip6table_mangle);
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net->ipv6.ip6table_mangle = NULL;
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}
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static struct pernet_operations ip6table_mangle_net_ops = {
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.pre_exit = ip6table_mangle_net_pre_exit,
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.exit = ip6table_mangle_net_exit,
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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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mangle_ops = xt_hook_ops_alloc(&packet_mangler, ip6table_mangle_hook);
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if (IS_ERR(mangle_ops))
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return PTR_ERR(mangle_ops);
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ret = register_pernet_subsys(&ip6table_mangle_net_ops);
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if (ret < 0) {
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kfree(mangle_ops);
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return ret;
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}
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ret = ip6table_mangle_table_init(&init_net);
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if (ret) {
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unregister_pernet_subsys(&ip6table_mangle_net_ops);
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kfree(mangle_ops);
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}
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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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unregister_pernet_subsys(&ip6table_mangle_net_ops);
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kfree(mangle_ops);
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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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