struct xt_match *xt_find_match(u8 af, const char *name, u8 revision)
{
	struct xt_match *m;
	int err = -ENOENT;

	if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN)
		return ERR_PTR(-EINVAL);

	mutex_lock(&xt[af].mutex);
	list_for_each_entry(m, &xt[af].match, list) {
		if (strcmp(m->name, name) == 0) {
			if (m->revision == revision) {
				if (try_module_get(m->me)) {
					mutex_unlock(&xt[af].mutex);
					return m;
				}
			} else
				err = -EPROTOTYPE; /* Found something. */
		}
	}
	mutex_unlock(&xt[af].mutex);

	if (af != NFPROTO_UNSPEC)
		/* Try searching again in the family-independent list */
		return xt_find_match(NFPROTO_UNSPEC, name, revision);

	return ERR_PTR(err);
}
struct xt_match *xt_find_match(u8 af, const char *name, u8 revision)
{
	struct xt_match *m;
	int err = -ENOENT;

	if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN)
		return ERR_PTR(-EINVAL);

	mutex_lock(&xt[af].mutex);
	list_for_each_entry(m, &xt[af].match, list) {
		if (strcmp(m->name, name) == 0) {
			if (m->revision == revision) {
				if (try_module_get(m->me)) {
					mutex_unlock(&xt[af].mutex);
					return m;
				}
			} else
				err = -EPROTOTYPE;  
		}
	}
	mutex_unlock(&xt[af].mutex);

	if (af != NFPROTO_UNSPEC)
		 
		return xt_find_match(NFPROTO_UNSPEC, name, revision);

	return ERR_PTR(err);
}