77 lines
1.7 KiB
C
77 lines
1.7 KiB
C
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/* This is a module which is used for setting up fake conntracks
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* on packets so that they are not seen by the conntrack/NAT code.
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*/
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv4/ip_conntrack.h>
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static unsigned int
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target(struct sk_buff **pskb,
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const struct net_device *in,
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const struct net_device *out,
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unsigned int hooknum,
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const void *targinfo,
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void *userinfo)
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{
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/* Previously seen (loopback)? Ignore. */
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if ((*pskb)->nfct != NULL)
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return IPT_CONTINUE;
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/* Attach fake conntrack entry.
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If there is a real ct entry correspondig to this packet,
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it'll hang aroun till timing out. We don't deal with it
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for performance reasons. JK */
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(*pskb)->nfct = &ip_conntrack_untracked.ct_general;
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(*pskb)->nfctinfo = IP_CT_NEW;
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nf_conntrack_get((*pskb)->nfct);
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return IPT_CONTINUE;
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}
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static int
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checkentry(const char *tablename,
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const struct ipt_entry *e,
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void *targinfo,
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unsigned int targinfosize,
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unsigned int hook_mask)
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{
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if (targinfosize != 0) {
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printk(KERN_WARNING "NOTRACK: targinfosize %u != 0\n",
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targinfosize);
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return 0;
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}
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if (strcmp(tablename, "raw") != 0) {
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printk(KERN_WARNING "NOTRACK: can only be called from \"raw\" table, not \"%s\"\n", tablename);
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return 0;
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}
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return 1;
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}
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static struct ipt_target ipt_notrack_reg = {
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.name = "NOTRACK",
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.target = target,
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.checkentry = checkentry,
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.me = THIS_MODULE
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};
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static int __init init(void)
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{
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if (ipt_register_target(&ipt_notrack_reg))
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return -EINVAL;
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return 0;
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}
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static void __exit fini(void)
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{
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ipt_unregister_target(&ipt_notrack_reg);
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}
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module_init(init);
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module_exit(fini);
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MODULE_LICENSE("GPL");
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