diff options
Diffstat (limited to 'net/ipv4/netfilter/ipt_NOTRACK.c')
-rw-r--r-- | net/ipv4/netfilter/ipt_NOTRACK.c | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_NOTRACK.c b/net/ipv4/netfilter/ipt_NOTRACK.c new file mode 100644 index 00000000000..a4bb9b3bc29 --- /dev/null +++ b/net/ipv4/netfilter/ipt_NOTRACK.c @@ -0,0 +1,76 @@ +/* This is a module which is used for setting up fake conntracks + * on packets so that they are not seen by the conntrack/NAT code. + */ +#include <linux/module.h> +#include <linux/skbuff.h> + +#include <linux/netfilter_ipv4/ip_tables.h> +#include <linux/netfilter_ipv4/ip_conntrack.h> + +static unsigned int +target(struct sk_buff **pskb, + const struct net_device *in, + const struct net_device *out, + unsigned int hooknum, + const void *targinfo, + void *userinfo) +{ + /* Previously seen (loopback)? Ignore. */ + if ((*pskb)->nfct != NULL) + return IPT_CONTINUE; + + /* Attach fake conntrack entry. + If there is a real ct entry correspondig to this packet, + it'll hang aroun till timing out. We don't deal with it + for performance reasons. JK */ + (*pskb)->nfct = &ip_conntrack_untracked.ct_general; + (*pskb)->nfctinfo = IP_CT_NEW; + nf_conntrack_get((*pskb)->nfct); + + return IPT_CONTINUE; +} + +static int +checkentry(const char *tablename, + const struct ipt_entry *e, + void *targinfo, + unsigned int targinfosize, + unsigned int hook_mask) +{ + if (targinfosize != 0) { + printk(KERN_WARNING "NOTRACK: targinfosize %u != 0\n", + targinfosize); + return 0; + } + + if (strcmp(tablename, "raw") != 0) { + printk(KERN_WARNING "NOTRACK: can only be called from \"raw\" table, not \"%s\"\n", tablename); + return 0; + } + + return 1; +} + +static struct ipt_target ipt_notrack_reg = { + .name = "NOTRACK", + .target = target, + .checkentry = checkentry, + .me = THIS_MODULE +}; + +static int __init init(void) +{ + if (ipt_register_target(&ipt_notrack_reg)) + return -EINVAL; + + return 0; +} + +static void __exit fini(void) +{ + ipt_unregister_target(&ipt_notrack_reg); +} + +module_init(init); +module_exit(fini); +MODULE_LICENSE("GPL"); |