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| 4 | |
| 5 | * (C) 2002-2005 Netfilter Core Team <[email protected]>
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| 6 |
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| 7 |
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| 8 | #include <linux/module.h>
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| 9 | #include <linux/skbuff.h>
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| 10 | #include <net/netfilter/nf_conntrack.h>
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| 11 | #include <linux/netfilter/x_tables.h>
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| 12 | #include <linux/netfilter/xt_state.h>
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| 13 |
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| 14 | MODULE_LICENSE("GPL");
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| 15 | MODULE_AUTHOR("Rusty Russell <[email protected]>");
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| 16 | MODULE_DESCRIPTION("ip[6]_tables connection tracking state match module");
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| 17 | MODULE_ALIAS("ipt_state");
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| 18 | MODULE_ALIAS("ip6t_state");
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| 19 |
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| 20 | static bool
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| 21 | state_mt(const struct sk_buff *skb, struct xt_action_param *par)
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| 22 | {
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| 23 | const struct xt_state_info *sinfo = par->matchinfo;
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| 24 | enum ip_conntrack_info ctinfo;
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| 25 | unsigned int statebit;
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| 26 | struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
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| 27 |
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| 28 | if (ct)
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| 29 | statebit = XT_STATE_BIT(ctinfo);
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| 30 | else if (ctinfo == IP_CT_UNTRACKED)
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| 31 | statebit = XT_STATE_UNTRACKED;
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| 32 | else
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| 33 | statebit = XT_STATE_INVALID;
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| 34 |
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| 35 | return (sinfo->statemask & statebit);
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| 36 | }
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| 37 |
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| 38 | static int state_mt_check(const struct xt_mtchk_param *par)
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| 39 | {
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| 40 | int ret;
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| 41 |
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| 42 | ret = nf_ct_netns_get(par->net, par->family);
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| 43 | if (ret < 0)
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| 44 | pr_info_ratelimited("cannot load conntrack support for proto=%u\n",
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| 45 | par->family);
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| 46 | return ret;
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| 47 | }
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| 48 |
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| 49 | static void state_mt_destroy(const struct xt_mtdtor_param *par)
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| 50 | {
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| 51 | nf_ct_netns_put(par->net, par->family);
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| 52 | }
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| 53 |
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| 54 | static struct xt_match state_mt_reg __read_mostly = {
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| 55 | .name = "state",
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| 56 | .family = NFPROTO_UNSPEC,
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| 57 | .checkentry = state_mt_check,
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| 58 | .match = state_mt,
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| 59 | .destroy = state_mt_destroy,
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| 60 | .matchsize = sizeof(struct xt_state_info),
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| 61 | .me = THIS_MODULE,
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| 62 | };
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| 63 |
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| 64 | static int __init state_mt_init(void)
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| 65 | {
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| 66 | return xt_register_match(&state_mt_reg);
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| 67 | }
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| 68 |
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| 69 | static void __exit state_mt_exit(void)
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| 70 | {
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| 71 | xt_unregister_match(&state_mt_reg);
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| 72 | }
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| 73 |
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| 74 | module_init(state_mt_init);
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| 75 | module_exit(state_mt_exit);
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