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11#include <linux/module.h>
12#include <linux/netfilter_ipv6/ip6_tables.h>
13#include <linux/slab.h>
14#include <net/ipv6.h>
15
16MODULE_LICENSE("GPL");
17MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
18MODULE_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
26static int __net_init ip6table_mangle_table_init(struct net *net);
27
28static const struct xt_table packet_mangler = {
29 .name = "mangle",
30 .valid_hooks = MANGLE_VALID_HOOKS,
31 .me = THIS_MODULE,
32 .af = NFPROTO_IPV6,
33 .priority = NF_IP6_PRI_MANGLE,
34 .table_init = ip6table_mangle_table_init,
35};
36
37static unsigned int
38ip6t_mangle_out(struct sk_buff *skb, const struct nf_hook_state *state)
39{
40 unsigned int ret;
41 struct in6_addr saddr, daddr;
42 u_int8_t hop_limit;
43 u_int32_t flowlabel, mark;
44 int err;
45
46
47 memcpy(&saddr, &ipv6_hdr(skb)->saddr, sizeof(saddr));
48 memcpy(&daddr, &ipv6_hdr(skb)->daddr, sizeof(daddr));
49 mark = skb->mark;
50 hop_limit = ipv6_hdr(skb)->hop_limit;
51
52
53 flowlabel = *((u_int32_t *)ipv6_hdr(skb));
54
55 ret = ip6t_do_table(skb, state, state->net->ipv6.ip6table_mangle);
56
57 if (ret != NF_DROP && ret != NF_STOLEN &&
58 (!ipv6_addr_equal(&ipv6_hdr(skb)->saddr, &saddr) ||
59 !ipv6_addr_equal(&ipv6_hdr(skb)->daddr, &daddr) ||
60 skb->mark != mark ||
61 ipv6_hdr(skb)->hop_limit != hop_limit ||
62 flowlabel != *((u_int32_t *)ipv6_hdr(skb)))) {
63 err = ip6_route_me_harder(state->net, skb);
64 if (err < 0)
65 ret = NF_DROP_ERR(err);
66 }
67
68 return ret;
69}
70
71
72static unsigned int
73ip6table_mangle_hook(void *priv, struct sk_buff *skb,
74 const struct nf_hook_state *state)
75{
76 if (state->hook == NF_INET_LOCAL_OUT)
77 return ip6t_mangle_out(skb, state);
78 return ip6t_do_table(skb, state, state->net->ipv6.ip6table_mangle);
79}
80
81static struct nf_hook_ops *mangle_ops __read_mostly;
82static int __net_init ip6table_mangle_table_init(struct net *net)
83{
84 struct ip6t_replace *repl;
85 int ret;
86
87 if (net->ipv6.ip6table_mangle)
88 return 0;
89
90 repl = ip6t_alloc_initial_table(&packet_mangler);
91 if (repl == NULL)
92 return -ENOMEM;
93 ret = ip6t_register_table(net, &packet_mangler, repl, mangle_ops,
94 &net->ipv6.ip6table_mangle);
95 kfree(repl);
96 return ret;
97}
98
99static void __net_exit ip6table_mangle_net_exit(struct net *net)
100{
101 if (!net->ipv6.ip6table_mangle)
102 return;
103
104 ip6t_unregister_table(net, net->ipv6.ip6table_mangle, mangle_ops);
105 net->ipv6.ip6table_mangle = NULL;
106}
107
108static struct pernet_operations ip6table_mangle_net_ops = {
109 .exit = ip6table_mangle_net_exit,
110};
111
112static int __init ip6table_mangle_init(void)
113{
114 int ret;
115
116 mangle_ops = xt_hook_ops_alloc(&packet_mangler, ip6table_mangle_hook);
117 if (IS_ERR(mangle_ops))
118 return PTR_ERR(mangle_ops);
119
120 ret = register_pernet_subsys(&ip6table_mangle_net_ops);
121 if (ret < 0) {
122 kfree(mangle_ops);
123 return ret;
124 }
125
126 ret = ip6table_mangle_table_init(&init_net);
127 if (ret) {
128 unregister_pernet_subsys(&ip6table_mangle_net_ops);
129 kfree(mangle_ops);
130 }
131 return ret;
132}
133
134static void __exit ip6table_mangle_fini(void)
135{
136 unregister_pernet_subsys(&ip6table_mangle_net_ops);
137 kfree(mangle_ops);
138}
139
140module_init(ip6table_mangle_init);
141module_exit(ip6table_mangle_fini);
142