#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/version.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter/x_tables.h>
#include "compat_xtnu.h"

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 19) && \
    LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 22)
static int xtnu_match_run(const struct sk_buff *skb,
    const struct net_device *in, const struct net_device *out,
    const struct xt_match *cm, const void *matchinfo, int offset,
    unsigned int protoff, int *hotdrop)
{
	struct xtnu_match *nm = xtcompat_numatch(cm);
	bool lo_drop, lo_ret;

	if (nm == NULL || nm->match == NULL)
		return false;
	lo_ret = nm->match(skb, in, out, nm, matchinfo,
	         offset, protoff, &lo_drop);
	*hotdrop = lo_drop;
	return lo_ret;
}

static int xtnu_match_check(const char *table, const void *entry,
    const struct xt_match *cm, void *matchinfo, unsigned int hook_mask)
{
	struct xtnu_match *nm = xtcompat_numatch(cm);

	if (nm == NULL)
		return false;
	if (nm->checkentry == NULL)
		return true;
	return nm->checkentry(table, entry, nm, matchinfo, hook_mask);
}

static void xtnu_match_destroy(const struct xt_match *cm, void *matchinfo)
{
	struct xtnu_match *nm = xtcompat_numatch(cm);

	if (nm != NULL && nm->destroy != NULL)
		nm->destroy(nm, matchinfo);
}

int xtnu_register_match(struct xtnu_match *nt)
{
	struct xt_match *ct;
	char *tmp;
	int ret;

	ct = kzalloc(sizeof(struct xt_match), GFP_KERNEL);
	if (ct == NULL)
		return -ENOMEM;

	tmp = (char *)ct->name;
	memcpy(tmp, nt->name, sizeof(nt->name));
	tmp = (char *)(ct->name + sizeof(ct->name) - sizeof(void *));
	*(tmp-1) = '\0';
	memcpy(tmp, &nt, sizeof(void *));

	ct->revision   = nt->revision;
	ct->family     = nt->family;
	ct->table      = (char *)nt->table;
	ct->hooks      = nt->hooks;
	ct->proto      = nt->proto;
	ct->match      = xtnu_match_run;
	ct->checkentry = xtnu_match_check;
	ct->destroy    = xtnu_match_destroy;
	ct->matchsize  = nt->matchsize;
	ct->me         = nt->me;

	nt->__compat_match = ct;
	ret = xt_register_match(ct);
	if (ret != 0)
		kfree(ct);
	return ret;
}
EXPORT_SYMBOL_GPL(xtnu_register_match);

int xtnu_register_matches(struct xtnu_match *nt, unsigned int num)
{
	unsigned int i;
	int ret;

	for (i = 0; i < num; ++i) {
		ret = xtnu_register_match(&nt[i]);
		if (ret < 0) {
			if (i > 0)
				xtnu_unregister_matches(nt, i);
			return ret;
		}
	}
	return 0;
}
EXPORT_SYMBOL_GPL(xtnu_register_matches);

void xtnu_unregister_match(struct xtnu_match *nt)
{
	xt_unregister_match(nt->__compat_match);
	kfree(nt->__compat_match);
}
EXPORT_SYMBOL_GPL(xtnu_unregister_match);

void xtnu_unregister_matches(struct xtnu_match *nt, unsigned int num)
{
	unsigned int i;

	for (i = 0; i < num; ++i)
		xtnu_unregister_match(&nt[i]);
}
EXPORT_SYMBOL_GPL(xtnu_unregister_matches);
#endif

#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 22)
static int xtnu_target_check(const char *table, const void *entry,
    const struct xt_target *ct, void *targinfo, unsigned int hook_mask)
{
	struct xtnu_target *nt = xtcompat_nutarget(ct);
	if (nt == NULL)
		return false;
	if (nt->checkentry == NULL)
		/* this is valid, just like if there was no function */
		return true;
	return nt->checkentry(table, entry, nt, targinfo, hook_mask);
}
#endif

#if LINUX_VERSION_CODE == KERNEL_VERSION(2, 6, 23)
static bool xtnu_target_check(const char *table, const void *entry,
    const struct xt_target *ct, void *targinfo, unsigned int hook_mask)
{
	struct xtnu_target *nt = xtcompat_nutarget(ct);
	if (nt == NULL)
		return false;
	if (nt->checkentry == NULL)
		/* this is valid, just like if there was no function */
		return true;
	return nt->checkentry(table, entry, nt, targinfo, hook_mask);
}
#endif

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 19) && \
    LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 23)
static unsigned int xtnu_target_run(struct sk_buff **pskb,
    const struct net_device *in, const struct net_device *out,
    unsigned int hooknum, const struct xt_target *ct, const void *targinfo)
{
	struct xtnu_target *nt = xtcompat_nutarget(ct);
	if (nt != NULL && nt->target != NULL)
		return nt->target(*pskb, in, out, hooknum, nt, targinfo);
	return XT_CONTINUE;
}

static void xtnu_target_destroy(const struct xt_target *ct, void *targinfo)
{
	struct xtnu_target *nt = xtcompat_nutarget(ct);
	if (nt != NULL && nt->destroy != NULL)
		nt->destroy(nt, targinfo);
}

int xtnu_register_target(struct xtnu_target *nt)
{
	struct xt_target *ct;
	char *tmp;
	int ret;

	ct = kzalloc(sizeof(struct xt_target), GFP_KERNEL);
	if (ct == NULL)
		return -ENOMEM;

	tmp = (char *)ct->name;
	memcpy(tmp, nt->name, sizeof(nt->name));
	tmp = (char *)(ct->name + sizeof(ct->name) - sizeof(void *));
	*(tmp-1) = '\0';
	memcpy(tmp, &nt, sizeof(void *));

	ct->revision   = nt->revision;
	ct->family     = nt->family;
	ct->table      = (char *)nt->table;
	ct->hooks      = nt->hooks;
	ct->proto      = nt->proto;
	ct->target     = xtnu_target_run;
	ct->checkentry = xtnu_target_check;
	ct->destroy    = xtnu_target_destroy;
	ct->targetsize = nt->targetsize;
	ct->me         = nt->me;

	nt->__compat_target = ct;
	ret = xt_register_target(ct);
	if (ret != 0)
		kfree(ct);
	return ret;
}
EXPORT_SYMBOL_GPL(xtnu_register_target);

void xtnu_unregister_target(struct xtnu_target *nt)
{
	xt_unregister_target(nt->__compat_target);
	kfree(nt->__compat_target);
}
EXPORT_SYMBOL_GPL(xtnu_unregister_target);

#endif

#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 23)
int xtnu_ip_route_me_harder(struct sk_buff *skb, unsigned int addr_type)
{
	return ip_route_me_harder(&skb, addr_type);
}
EXPORT_SYMBOL_GPL(xtnu_ip_route_me_harder);
#endif

MODULE_LICENSE("GPL");