| | 1 | /* |
| | 2 | * IPv6 packet mangling table, a port of the IPv4 mangle table to IPv6 |
| | 3 | * |
| | 4 | * Copyright (C) 2000-2001 by Harald Welte <laforge@gnumonks.org> |
| | 5 | * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org> |
| | 6 | * |
| | 7 | * This program is free software; you can redistribute it and/or modify |
| | 8 | * it under the terms of the GNU General Public License version 2 as |
| | 9 | * published by the Free Software Foundation. |
| | 10 | */ |
| | 11 | #include <linux/module.h> |
| | 12 | #include <linux/netfilter_ipv6/ip6_tables.h> |
| | 13 | #include <linux/slab.h> |
| | 14 | #include <net/ipv6.h> |
| | 15 | |
| | 16 | MODULE_LICENSE("GPL"); |
| | 17 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); |
| | 18 | MODULE_DESCRIPTION("ip6tables mangle table"); |
| | 19 | |
| | 20 | #define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \ |
| | 21 | (1 << NF_INET_LOCAL_IN) | \ |
| | 22 | (1 << NF_INET_FORWARD) | \ |
| | 23 | (1 << NF_INET_LOCAL_OUT) | \ |
| | 24 | (1 << NF_INET_POST_ROUTING)) |
| | 25 | |
| | 26 | static const struct xt_table packet_mangler = { |
| | 27 | .name = "mangle", |
| | 28 | .valid_hooks = MANGLE_VALID_HOOKS, |
| | 29 | .me = THIS_MODULE, |
| | 30 | .af = NFPROTO_IPV6, |
| | 31 | .priority = NF_IP6_PRI_MANGLE, |
| | 32 | }; |
| | 33 | |
| | 34 | static unsigned int |
| | 35 | ip6t_mangle_out(struct sk_buff *skb, const struct net_device *out) |
| | 36 | { |
| | 37 | unsigned int ret; |
| | 38 | struct in6_addr saddr, daddr; |
| | 39 | u_int8_t hop_limit; |
| | 40 | u_int32_t flowlabel, mark; |
| | 41 | int err; |
| | 42 | #if 0 |
| | 43 | /* root is playing with raw sockets. */ |
| | 44 | if (skb->len < sizeof(struct iphdr) || |
| | 45 | ip_hdrlen(skb) < sizeof(struct iphdr)) { |
| | 46 | net_warn_ratelimited("ip6t_hook: happy cracking\n"); |
| | 47 | return NF_ACCEPT; |
| | 48 | } |
| | 49 | #endif |
| | 50 | |
| | 51 | /* save source/dest address, mark, hoplimit, flowlabel, priority, */ |
| | 52 | memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr)); |
| | 53 | memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr)); |
| | 54 | mark = skb->mark; |
| | 55 | hop_limit = ipv6_hdr(skb)->hop_limit; |
| | 56 | |
| | 57 | /* flowlabel and prio (includes version, which shouldn't change either */ |
| | 58 | flowlabel = *((u_int32_t *)ipv6_hdr(skb)); |
| | 59 | |
| | 60 | ret = ip6t_do_table(skb, NF_INET_LOCAL_OUT, NULL, out, |
| | 61 | dev_net(out)->ipv6.ip6table_mangle); |
| | 62 | |
| | 63 | if (ret != NF_DROP && ret != NF_STOLEN && |
| | 64 | (!ipv6_addr_equal(&ipv6_hdr(skb)->saddr, &saddr) || |
| | 65 | !ipv6_addr_equal(&ipv6_hdr(skb)->daddr, &daddr) || |
| | 66 | skb->mark != mark || |
| | 67 | ipv6_hdr(skb)->hop_limit != hop_limit || |
| | 68 | flowlabel != *((u_int32_t *)ipv6_hdr(skb)))) { |
| | 69 | err = ip6_route_me_harder(skb); |
| | 70 | if (err < 0) |
| | 71 | ret = NF_DROP_ERR(err); |
| | 72 | } |
| | 73 | |
| | 74 | return ret; |
| | 75 | } |
| | 76 | |
| | 77 | /* The work comes in here from netfilter.c. */ |
| | 78 | static unsigned int |
| | 79 | ip6table_mangle_hook(unsigned int hook, struct sk_buff *skb, |
| | 80 | const struct net_device *in, const struct net_device *out, |
| | 81 | int (*okfn)(struct sk_buff *)) |
| | 82 | { |
| | 83 | if (hook == NF_INET_LOCAL_OUT) |
| | 84 | return ip6t_mangle_out(skb, out); |
| | 85 | if (hook == NF_INET_POST_ROUTING) |
| | 86 | return ip6t_do_table(skb, hook, in, out, |
| | 87 | dev_net(out)->ipv6.ip6table_mangle); |
| | 88 | /* INPUT/FORWARD */ |
| | 89 | return ip6t_do_table(skb, hook, in, out, |
| | 90 | dev_net(in)->ipv6.ip6table_mangle); |
| | 91 | } |
| | 92 | |
| | 93 | static struct nf_hook_ops *mangle_ops __read_mostly; |
| | 94 | static int __net_init ip6table_mangle_net_init(struct net *net) |
| | 95 | { |
| | 96 | struct ip6t_replace *repl; |
| | 97 | |
| | 98 | repl = ip6t_alloc_initial_table(&packet_mangler); |
| | 99 | if (repl == NULL) |
| | 100 | return -ENOMEM; |
| | 101 | net->ipv6.ip6table_mangle = |
| | 102 | ip6t_register_table(net, &packet_mangler, repl); |
| | 103 | kfree(repl); |
| | 104 | return PTR_RET(net->ipv6.ip6table_mangle); |
| | 105 | } |
| | 106 | |
| | 107 | static void __net_exit ip6table_mangle_net_exit(struct net *net) |
| | 108 | { |
| | 109 | ip6t_unregister_table(net, net->ipv6.ip6table_mangle); |
| | 110 | } |
| | 111 | |
| | 112 | static struct pernet_operations ip6table_mangle_net_ops = { |
| | 113 | .init = ip6table_mangle_net_init, |
| | 114 | .exit = ip6table_mangle_net_exit, |
| | 115 | }; |
| | 116 | |
| | 117 | static int __init ip6table_mangle_init(void) |
| | 118 | { |
| | 119 | int ret; |
| | 120 | |
| | 121 | ret = register_pernet_subsys(&ip6table_mangle_net_ops); |
| | 122 | if (ret < 0) |
| | 123 | return ret; |
| | 124 | |
| | 125 | /* Register hooks */ |
| | 126 | mangle_ops = xt_hook_link(&packet_mangler, ip6table_mangle_hook); |
| | 127 | if (IS_ERR(mangle_ops)) { |
| | 128 | ret = PTR_ERR(mangle_ops); |
| | 129 | goto cleanup_table; |
| | 130 | } |
| | 131 | |
| | 132 | return ret; |
| | 133 | |
| | 134 | cleanup_table: |
| | 135 | unregister_pernet_subsys(&ip6table_mangle_net_ops); |
| | 136 | return ret; |
| | 137 | } |
| | 138 | |
| | 139 | static void __exit ip6table_mangle_fini(void) |
| | 140 | { |
| | 141 | xt_hook_unlink(&packet_mangler, mangle_ops); |
| | 142 | unregister_pernet_subsys(&ip6table_mangle_net_ops); |
| | 143 | } |
| | 144 | |
| | 145 | module_init(ip6table_mangle_init); |
| | 146 | module_exit(ip6table_mangle_fini); |
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