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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 | // SPDX-License-Identifier: GPL-2.0-only /* * 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> */ #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(void *priv, 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; /* 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(priv, skb, state); 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, state->sk, 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(priv, skb, state); return ip6t_do_table(priv, skb, state); } static struct nf_hook_ops *mangle_ops __read_mostly; static int ip6table_mangle_table_init(struct net *net) { struct ip6t_replace *repl; int ret; repl = ip6t_alloc_initial_table(&packet_mangler); if (repl == NULL) return -ENOMEM; ret = ip6t_register_table(net, &packet_mangler, repl, mangle_ops); kfree(repl); return ret; } static void __net_exit ip6table_mangle_net_pre_exit(struct net *net) { ip6t_unregister_table_pre_exit(net, "mangle"); } static void __net_exit ip6table_mangle_net_exit(struct net *net) { ip6t_unregister_table_exit(net, "mangle"); } static struct pernet_operations ip6table_mangle_net_ops = { .pre_exit = ip6table_mangle_net_pre_exit, .exit = ip6table_mangle_net_exit, }; static int __init ip6table_mangle_init(void) { int ret = xt_register_template(&packet_mangler, ip6table_mangle_table_init); if (ret < 0) return ret; mangle_ops = xt_hook_ops_alloc(&packet_mangler, ip6table_mangle_hook); if (IS_ERR(mangle_ops)) { xt_unregister_template(&packet_mangler); return PTR_ERR(mangle_ops); } ret = register_pernet_subsys(&ip6table_mangle_net_ops); if (ret < 0) { xt_unregister_template(&packet_mangler); kfree(mangle_ops); return ret; } return ret; } static void __exit ip6table_mangle_fini(void) { unregister_pernet_subsys(&ip6table_mangle_net_ops); xt_unregister_template(&packet_mangler); kfree(mangle_ops); } module_init(ip6table_mangle_init); module_exit(ip6table_mangle_fini); |