[net-next-2.6.git] / net / netfilter / nf_conntrack_proto_gre.c

/*
 * ip_conntrack_proto_gre.c - Version 3.0
 *
 * Connection tracking protocol helper module for GRE.
 *
 * GRE is a generic encapsulation protocol, which is generally not very
 * suited for NAT, as it has no protocol-specific part as port numbers.
 *
 * It has an optional key field, which may help us distinguishing two
 * connections between the same two hosts.
 *
 * GRE is defined in RFC 1701 and RFC 1702, as well as RFC 2784
 *
 * PPTP is built on top of a modified version of GRE, and has a mandatory
 * field called "CallID", which serves us for the same purpose as the key
 * field in plain GRE.
 *
 * Documentation about PPTP can be found in RFC 2637
 *
 * (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
 *
 * Development of this code funded by Astaro AG (http://www.astaro.com/)
 *
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/list.h>
#include <linux/seq_file.h>
#include <linux/in.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/dst.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <linux/netfilter/nf_conntrack_proto_gre.h>
#include <linux/netfilter/nf_conntrack_pptp.h>

#define GRE_TIMEOUT		(30 * HZ)
#define GRE_STREAM_TIMEOUT	(180 * HZ)

static int proto_gre_net_id __read_mostly;
struct netns_proto_gre {
	rwlock_t		keymap_lock;
	struct list_head	keymap_list;
};

void nf_ct_gre_keymap_flush(struct net *net)
{
	struct netns_proto_gre *net_gre = net_generic(net, proto_gre_net_id);
	struct nf_ct_gre_keymap *km, *tmp;

	write_lock_bh(&net_gre->keymap_lock);
	list_for_each_entry_safe(km, tmp, &net_gre->keymap_list, list) {
		list_del(&km->list);
		kfree(km);
	}
	write_unlock_bh(&net_gre->keymap_lock);
}
EXPORT_SYMBOL(nf_ct_gre_keymap_flush);

static inline int gre_key_cmpfn(const struct nf_ct_gre_keymap *km,
				const struct nf_conntrack_tuple *t)
{
	return km->tuple.src.l3num == t->src.l3num &&
	       !memcmp(&km->tuple.src.u3, &t->src.u3, sizeof(t->src.u3)) &&
	       !memcmp(&km->tuple.dst.u3, &t->dst.u3, sizeof(t->dst.u3)) &&
	       km->tuple.dst.protonum == t->dst.protonum &&
	       km->tuple.dst.u.all == t->dst.u.all;
}

/* look up the source key for a given tuple */
static __be16 gre_keymap_lookup(struct net *net, struct nf_conntrack_tuple *t)
{
	struct netns_proto_gre *net_gre = net_generic(net, proto_gre_net_id);
	struct nf_ct_gre_keymap *km;
	__be16 key = 0;

	read_lock_bh(&net_gre->keymap_lock);
	list_for_each_entry(km, &net_gre->keymap_list, list) {
		if (gre_key_cmpfn(km, t)) {
			key = km->tuple.src.u.gre.key;
			break;
		}
	}
	read_unlock_bh(&net_gre->keymap_lock);

	pr_debug("lookup src key 0x%x for ", key);
	nf_ct_dump_tuple(t);

	return key;
}

/* add a single keymap entry, associate with specified master ct */
int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir,
			 struct nf_conntrack_tuple *t)
{
	struct net *net = nf_ct_net(ct);
	struct netns_proto_gre *net_gre = net_generic(net, proto_gre_net_id);
	struct nf_conn_help *help = nfct_help(ct);
	struct nf_ct_gre_keymap **kmp, *km;

	kmp = &help->help.ct_pptp_info.keymap[dir];
	if (*kmp) {
		/* check whether it's a retransmission */
		read_lock_bh(&net_gre->keymap_lock);
		list_for_each_entry(km, &net_gre->keymap_list, list) {
			if (gre_key_cmpfn(km, t) && km == *kmp) {
				read_unlock_bh(&net_gre->keymap_lock);
				return 0;
			}
		}
		read_unlock_bh(&net_gre->keymap_lock);
		pr_debug("trying to override keymap_%s for ct %p\n",
			 dir == IP_CT_DIR_REPLY ? "reply" : "orig", ct);
		return -EEXIST;
	}

	km = kmalloc(sizeof(*km), GFP_ATOMIC);
	if (!km)
		return -ENOMEM;
	memcpy(&km->tuple, t, sizeof(*t));
	*kmp = km;

	pr_debug("adding new entry %p: ", km);
	nf_ct_dump_tuple(&km->tuple);

	write_lock_bh(&net_gre->keymap_lock);
	list_add_tail(&km->list, &net_gre->keymap_list);
	write_unlock_bh(&net_gre->keymap_lock);

	return 0;
}
EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_add);

/* destroy the keymap entries associated with specified master ct */
void nf_ct_gre_keymap_destroy(struct nf_conn *ct)
{
	struct net *net = nf_ct_net(ct);
	struct netns_proto_gre *net_gre = net_generic(net, proto_gre_net_id);
	struct nf_conn_help *help = nfct_help(ct);
	enum ip_conntrack_dir dir;

	pr_debug("entering for ct %p\n", ct);

	write_lock_bh(&net_gre->keymap_lock);
	for (dir = IP_CT_DIR_ORIGINAL; dir < IP_CT_DIR_MAX; dir++) {
		if (help->help.ct_pptp_info.keymap[dir]) {
			pr_debug("removing %p from list\n",
				 help->help.ct_pptp_info.keymap[dir]);
			list_del(&help->help.ct_pptp_info.keymap[dir]->list);
			kfree(help->help.ct_pptp_info.keymap[dir]);
			help->help.ct_pptp_info.keymap[dir] = NULL;
		}
	}
	write_unlock_bh(&net_gre->keymap_lock);
}
EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_destroy);

/* PUBLIC CONNTRACK PROTO HELPER FUNCTIONS */

/* invert gre part of tuple */
static bool gre_invert_tuple(struct nf_conntrack_tuple *tuple,
			     const struct nf_conntrack_tuple *orig)
{
	tuple->dst.u.gre.key = orig->src.u.gre.key;
	tuple->src.u.gre.key = orig->dst.u.gre.key;
	return true;
}

/* gre hdr info to tuple */
static bool gre_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
			     struct nf_conntrack_tuple *tuple)
{
	struct net *net = dev_net(skb->dev ? skb->dev : skb_dst(skb)->dev);
	const struct gre_hdr_pptp *pgrehdr;
	struct gre_hdr_pptp _pgrehdr;
	__be16 srckey;
	const struct gre_hdr *grehdr;
	struct gre_hdr _grehdr;

	/* first only delinearize old RFC1701 GRE header */
	grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
	if (!grehdr || grehdr->version != GRE_VERSION_PPTP) {
		/* try to behave like "nf_conntrack_proto_generic" */
		tuple->src.u.all = 0;
		tuple->dst.u.all = 0;
		return true;
	}

	/* PPTP header is variable length, only need up to the call_id field */
	pgrehdr = skb_header_pointer(skb, dataoff, 8, &_pgrehdr);
	if (!pgrehdr)
		return true;

	if (ntohs(grehdr->protocol) != GRE_PROTOCOL_PPTP) {
		pr_debug("GRE_VERSION_PPTP but unknown proto\n");
		return false;
	}

	tuple->dst.u.gre.key = pgrehdr->call_id;
	srckey = gre_keymap_lookup(net, tuple);
	tuple->src.u.gre.key = srckey;

	return true;
}

/* print gre part of tuple */
static int gre_print_tuple(struct seq_file *s,
			   const struct nf_conntrack_tuple *tuple)
{
	return seq_printf(s, "srckey=0x%x dstkey=0x%x ",
			  ntohs(tuple->src.u.gre.key),
			  ntohs(tuple->dst.u.gre.key));
}

/* print private data for conntrack */
static int gre_print_conntrack(struct seq_file *s, struct nf_conn *ct)
{
	return seq_printf(s, "timeout=%u, stream_timeout=%u ",
			  (ct->proto.gre.timeout / HZ),
			  (ct->proto.gre.stream_timeout / HZ));
}

/* Returns verdict for packet, and may modify conntrack */
static int gre_packet(struct nf_conn *ct,
		      const struct sk_buff *skb,
		      unsigned int dataoff,
		      enum ip_conntrack_info ctinfo,
		      u_int8_t pf,
		      unsigned int hooknum)
{
	/* If we've seen traffic both ways, this is a GRE connection.
	 * Extend timeout. */
	if (ct->status & IPS_SEEN_REPLY) {
		nf_ct_refresh_acct(ct, ctinfo, skb,
				   ct->proto.gre.stream_timeout);
		/* Also, more likely to be important, and not a probe. */
		set_bit(IPS_ASSURED_BIT, &ct->status);
		nf_conntrack_event_cache(IPCT_ASSURED, ct);
	} else
		nf_ct_refresh_acct(ct, ctinfo, skb,
				   ct->proto.gre.timeout);

	return NF_ACCEPT;
}

/* Called when a new connection for this protocol found. */
static bool gre_new(struct nf_conn *ct, const struct sk_buff *skb,
		    unsigned int dataoff)
{
	pr_debug(": ");
	nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);

	/* initialize to sane value.  Ideally a conntrack helper
	 * (e.g. in case of pptp) is increasing them */
	ct->proto.gre.stream_timeout = GRE_STREAM_TIMEOUT;
	ct->proto.gre.timeout = GRE_TIMEOUT;

	return true;
}

/* Called when a conntrack entry has already been removed from the hashes
 * and is about to be deleted from memory */
static void gre_destroy(struct nf_conn *ct)
{
	struct nf_conn *master = ct->master;
	pr_debug(" entering\n");

	if (!master)
		pr_debug("no master !?!\n");
	else
		nf_ct_gre_keymap_destroy(master);
}

/* protocol helper struct */
static struct nf_conntrack_l4proto nf_conntrack_l4proto_gre4 __read_mostly = {
	.l3proto	 = AF_INET,
	.l4proto	 = IPPROTO_GRE,
	.name		 = "gre",
	.pkt_to_tuple	 = gre_pkt_to_tuple,
	.invert_tuple	 = gre_invert_tuple,
	.print_tuple	 = gre_print_tuple,
	.print_conntrack = gre_print_conntrack,
	.packet		 = gre_packet,
	.new		 = gre_new,
	.destroy	 = gre_destroy,
	.me 		 = THIS_MODULE,
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
	.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
	.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
	.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
	.nla_policy	 = nf_ct_port_nla_policy,
#endif
};

static int proto_gre_net_init(struct net *net)
{
	struct netns_proto_gre *net_gre = net_generic(net, proto_gre_net_id);

	rwlock_init(&net_gre->keymap_lock);
	INIT_LIST_HEAD(&net_gre->keymap_list);

	return 0;
}

static void proto_gre_net_exit(struct net *net)
{
	nf_ct_gre_keymap_flush(net);
}

static struct pernet_operations proto_gre_net_ops = {
	.init = proto_gre_net_init,
	.exit = proto_gre_net_exit,
	.id   = &proto_gre_net_id,
	.size = sizeof(struct netns_proto_gre),
};

static int __init nf_ct_proto_gre_init(void)
{
	int rv;

	rv = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_gre4);
	if (rv < 0)
		return rv;
	rv = register_pernet_subsys(&proto_gre_net_ops);
	if (rv < 0)
		nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_gre4);
	return rv;
}

static void __exit nf_ct_proto_gre_fini(void)
{
	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_gre4);
	unregister_pernet_subsys(&proto_gre_net_ops);
}

module_init(nf_ct_proto_gre_init);
module_exit(nf_ct_proto_gre_fini);

MODULE_LICENSE("GPL");
Commit	Line	Data
	1	/*
	2	* ip_conntrack_proto_gre.c - Version 3.0
	3	*
	4	* Connection tracking protocol helper module for GRE.
	5	*
	6	* GRE is a generic encapsulation protocol, which is generally not very
	7	* suited for NAT, as it has no protocol-specific part as port numbers.
	8	*
	9	* It has an optional key field, which may help us distinguishing two
	10	* connections between the same two hosts.
	11	*
	12	* GRE is defined in RFC 1701 and RFC 1702, as well as RFC 2784
	13	*
	14	* PPTP is built on top of a modified version of GRE, and has a mandatory
	15	* field called "CallID", which serves us for the same purpose as the key
	16	* field in plain GRE.
	17	*
	18	* Documentation about PPTP can be found in RFC 2637
	19	*
	20	* (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
	21	*
	22	* Development of this code funded by Astaro AG (http://www.astaro.com/)
	23	*
	24	*/
	25
	26	#include <linux/module.h>
	27	#include <linux/types.h>
	28	#include <linux/timer.h>
	29	#include <linux/list.h>
	30	#include <linux/seq_file.h>
	31	#include <linux/in.h>
	32	#include <linux/netdevice.h>
	33	#include <linux/skbuff.h>
	34	#include <net/dst.h>
	35	#include <net/net_namespace.h>
	36	#include <net/netns/generic.h>
	37	#include <net/netfilter/nf_conntrack_l4proto.h>
	38	#include <net/netfilter/nf_conntrack_helper.h>
	39	#include <net/netfilter/nf_conntrack_core.h>
	40	#include <linux/netfilter/nf_conntrack_proto_gre.h>
	41	#include <linux/netfilter/nf_conntrack_pptp.h>
	42
	43	#define GRE_TIMEOUT (30 * HZ)
	44	#define GRE_STREAM_TIMEOUT (180 * HZ)
	45
	46	static int proto_gre_net_id __read_mostly;
	47	struct netns_proto_gre {
	48	rwlock_t keymap_lock;
	49	struct list_head keymap_list;
	50	};
	51
	52	void nf_ct_gre_keymap_flush(struct net *net)
	53	{
	54	struct netns_proto_gre *net_gre = net_generic(net, proto_gre_net_id);
	55	struct nf_ct_gre_keymap km, tmp;
	56
	57	write_lock_bh(&net_gre->keymap_lock);
	58	list_for_each_entry_safe(km, tmp, &net_gre->keymap_list, list) {
	59	list_del(&km->list);
	60	kfree(km);
	61	}
	62	write_unlock_bh(&net_gre->keymap_lock);
	63	}
	64	EXPORT_SYMBOL(nf_ct_gre_keymap_flush);
	65
	66	static inline int gre_key_cmpfn(const struct nf_ct_gre_keymap *km,
	67	const struct nf_conntrack_tuple *t)
	68	{
	69	return km->tuple.src.l3num == t->src.l3num &&
	70	!memcmp(&km->tuple.src.u3, &t->src.u3, sizeof(t->src.u3)) &&
	71	!memcmp(&km->tuple.dst.u3, &t->dst.u3, sizeof(t->dst.u3)) &&
	72	km->tuple.dst.protonum == t->dst.protonum &&
	73	km->tuple.dst.u.all == t->dst.u.all;
	74	}
	75
	76	/* look up the source key for a given tuple */
	77	static __be16 gre_keymap_lookup(struct net net, struct nf_conntrack_tuple t)
	78	{
	79	struct netns_proto_gre *net_gre = net_generic(net, proto_gre_net_id);
	80	struct nf_ct_gre_keymap *km;
	81	__be16 key = 0;
	82
	83	read_lock_bh(&net_gre->keymap_lock);
	84	list_for_each_entry(km, &net_gre->keymap_list, list) {
	85	if (gre_key_cmpfn(km, t)) {
	86	key = km->tuple.src.u.gre.key;
	87	break;
	88	}
	89	}
	90	read_unlock_bh(&net_gre->keymap_lock);
	91
	92	pr_debug("lookup src key 0x%x for ", key);
	93	nf_ct_dump_tuple(t);
	94
	95	return key;
	96	}
	97
	98	/* add a single keymap entry, associate with specified master ct */
	99	int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir,
	100	struct nf_conntrack_tuple *t)
	101	{
	102	struct net *net = nf_ct_net(ct);
	103	struct netns_proto_gre *net_gre = net_generic(net, proto_gre_net_id);
	104	struct nf_conn_help *help = nfct_help(ct);
	105	struct nf_ct_gre_keymap *kmp, km;
	106
	107	kmp = &help->help.ct_pptp_info.keymap[dir];
	108	if (*kmp) {
	109	/* check whether it's a retransmission */
	110	read_lock_bh(&net_gre->keymap_lock);
	111	list_for_each_entry(km, &net_gre->keymap_list, list) {
	112	if (gre_key_cmpfn(km, t) && km == *kmp) {
	113	read_unlock_bh(&net_gre->keymap_lock);
	114	return 0;
	115	}
	116	}
	117	read_unlock_bh(&net_gre->keymap_lock);
	118	pr_debug("trying to override keymap_%s for ct %p\n",
	119	dir == IP_CT_DIR_REPLY ? "reply" : "orig", ct);
	120	return -EEXIST;
	121	}
	122
	123	km = kmalloc(sizeof(*km), GFP_ATOMIC);
	124	if (!km)
	125	return -ENOMEM;
	126	memcpy(&km->tuple, t, sizeof(*t));
	127	*kmp = km;
	128
	129	pr_debug("adding new entry %p: ", km);
	130	nf_ct_dump_tuple(&km->tuple);
	131
	132	write_lock_bh(&net_gre->keymap_lock);
	133	list_add_tail(&km->list, &net_gre->keymap_list);
	134	write_unlock_bh(&net_gre->keymap_lock);
	135
	136	return 0;
	137	}
	138	EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_add);
	139
	140	/* destroy the keymap entries associated with specified master ct */
	141	void nf_ct_gre_keymap_destroy(struct nf_conn *ct)
	142	{
	143	struct net *net = nf_ct_net(ct);
	144	struct netns_proto_gre *net_gre = net_generic(net, proto_gre_net_id);
	145	struct nf_conn_help *help = nfct_help(ct);
	146	enum ip_conntrack_dir dir;
	147
	148	pr_debug("entering for ct %p\n", ct);
	149
	150	write_lock_bh(&net_gre->keymap_lock);
	151	for (dir = IP_CT_DIR_ORIGINAL; dir < IP_CT_DIR_MAX; dir++) {
	152	if (help->help.ct_pptp_info.keymap[dir]) {
	153	pr_debug("removing %p from list\n",
	154	help->help.ct_pptp_info.keymap[dir]);
	155	list_del(&help->help.ct_pptp_info.keymap[dir]->list);
	156	kfree(help->help.ct_pptp_info.keymap[dir]);
	157	help->help.ct_pptp_info.keymap[dir] = NULL;
	158	}
	159	}
	160	write_unlock_bh(&net_gre->keymap_lock);
	161	}
	162	EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_destroy);
	163
	164	/* PUBLIC CONNTRACK PROTO HELPER FUNCTIONS */
	165
	166	/* invert gre part of tuple */
	167	static bool gre_invert_tuple(struct nf_conntrack_tuple *tuple,
	168	const struct nf_conntrack_tuple *orig)
	169	{
	170	tuple->dst.u.gre.key = orig->src.u.gre.key;
	171	tuple->src.u.gre.key = orig->dst.u.gre.key;
	172	return true;
	173	}
	174
	175	/* gre hdr info to tuple */
	176	static bool gre_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
	177	struct nf_conntrack_tuple *tuple)
	178	{
	179	struct net *net = dev_net(skb->dev ? skb->dev : skb_dst(skb)->dev);
	180	const struct gre_hdr_pptp *pgrehdr;
	181	struct gre_hdr_pptp _pgrehdr;
	182	__be16 srckey;
	183	const struct gre_hdr *grehdr;
	184	struct gre_hdr _grehdr;
	185
	186	/* first only delinearize old RFC1701 GRE header */
	187	grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
	188	if (!grehdr \|\| grehdr->version != GRE_VERSION_PPTP) {
	189	/* try to behave like "nf_conntrack_proto_generic" */
	190	tuple->src.u.all = 0;
	191	tuple->dst.u.all = 0;
	192	return true;
	193	}
	194
	195	/* PPTP header is variable length, only need up to the call_id field */
	196	pgrehdr = skb_header_pointer(skb, dataoff, 8, &_pgrehdr);
	197	if (!pgrehdr)
	198	return true;
	199
	200	if (ntohs(grehdr->protocol) != GRE_PROTOCOL_PPTP) {
	201	pr_debug("GRE_VERSION_PPTP but unknown proto\n");
	202	return false;
	203	}
	204
	205	tuple->dst.u.gre.key = pgrehdr->call_id;
	206	srckey = gre_keymap_lookup(net, tuple);
	207	tuple->src.u.gre.key = srckey;
	208
	209	return true;
	210	}
	211
	212	/* print gre part of tuple */
	213	static int gre_print_tuple(struct seq_file *s,
	214	const struct nf_conntrack_tuple *tuple)
	215	{
	216	return seq_printf(s, "srckey=0x%x dstkey=0x%x ",
	217	ntohs(tuple->src.u.gre.key),
	218	ntohs(tuple->dst.u.gre.key));
	219	}
	220
	221	/* print private data for conntrack */
	222	static int gre_print_conntrack(struct seq_file s, struct nf_conn ct)
	223	{
	224	return seq_printf(s, "timeout=%u, stream_timeout=%u ",
	225	(ct->proto.gre.timeout / HZ),
	226	(ct->proto.gre.stream_timeout / HZ));
	227	}
	228
	229	/* Returns verdict for packet, and may modify conntrack */
	230	static int gre_packet(struct nf_conn *ct,
	231	const struct sk_buff *skb,
	232	unsigned int dataoff,
	233	enum ip_conntrack_info ctinfo,
	234	u_int8_t pf,
	235	unsigned int hooknum)
	236	{
	237	/* If we've seen traffic both ways, this is a GRE connection.
	238	* Extend timeout. */
	239	if (ct->status & IPS_SEEN_REPLY) {
	240	nf_ct_refresh_acct(ct, ctinfo, skb,
	241	ct->proto.gre.stream_timeout);
	242	/* Also, more likely to be important, and not a probe. */
	243	set_bit(IPS_ASSURED_BIT, &ct->status);
	244	nf_conntrack_event_cache(IPCT_ASSURED, ct);
	245	} else
	246	nf_ct_refresh_acct(ct, ctinfo, skb,
	247	ct->proto.gre.timeout);
	248
	249	return NF_ACCEPT;
	250	}
	251
	252	/* Called when a new connection for this protocol found. */
	253	static bool gre_new(struct nf_conn ct, const struct sk_buff skb,
	254	unsigned int dataoff)
	255	{
	256	pr_debug(": ");
	257	nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
	258
	259	/* initialize to sane value. Ideally a conntrack helper
	260	* (e.g. in case of pptp) is increasing them */
	261	ct->proto.gre.stream_timeout = GRE_STREAM_TIMEOUT;
	262	ct->proto.gre.timeout = GRE_TIMEOUT;
	263
	264	return true;
	265	}
	266
	267	/* Called when a conntrack entry has already been removed from the hashes
	268	* and is about to be deleted from memory */
	269	static void gre_destroy(struct nf_conn *ct)
	270	{
	271	struct nf_conn *master = ct->master;
	272	pr_debug(" entering\n");
	273
	274	if (!master)
	275	pr_debug("no master !?!\n");
	276	else
	277	nf_ct_gre_keymap_destroy(master);
	278	}
	279
	280	/* protocol helper struct */
	281	static struct nf_conntrack_l4proto nf_conntrack_l4proto_gre4 __read_mostly = {
	282	.l3proto = AF_INET,
	283	.l4proto = IPPROTO_GRE,
	284	.name = "gre",
	285	.pkt_to_tuple = gre_pkt_to_tuple,
	286	.invert_tuple = gre_invert_tuple,
	287	.print_tuple = gre_print_tuple,
	288	.print_conntrack = gre_print_conntrack,
	289	.packet = gre_packet,
	290	.new = gre_new,
	291	.destroy = gre_destroy,
	292	.me = THIS_MODULE,
	293	#if defined(CONFIG_NF_CT_NETLINK) \|\| defined(CONFIG_NF_CT_NETLINK_MODULE)
	294	.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
	295	.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
	296	.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
	297	.nla_policy = nf_ct_port_nla_policy,
	298	#endif
	299	};
	300
	301	static int proto_gre_net_init(struct net *net)
	302	{
	303	struct netns_proto_gre *net_gre = net_generic(net, proto_gre_net_id);
	304
	305	rwlock_init(&net_gre->keymap_lock);
	306	INIT_LIST_HEAD(&net_gre->keymap_list);
	307
	308	return 0;
	309	}
	310
	311	static void proto_gre_net_exit(struct net *net)
	312	{
	313	nf_ct_gre_keymap_flush(net);
	314	}
	315
	316	static struct pernet_operations proto_gre_net_ops = {
	317	.init = proto_gre_net_init,
	318	.exit = proto_gre_net_exit,
	319	.id = &proto_gre_net_id,
	320	.size = sizeof(struct netns_proto_gre),
	321	};
	322
	323	static int __init nf_ct_proto_gre_init(void)
	324	{
	325	int rv;
	326
	327	rv = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_gre4);
	328	if (rv < 0)
	329	return rv;
	330	rv = register_pernet_subsys(&proto_gre_net_ops);
	331	if (rv < 0)
	332	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_gre4);
	333	return rv;
	334	}
	335
	336	static void __exit nf_ct_proto_gre_fini(void)
	337	{
	338	nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_gre4);
	339	unregister_pernet_subsys(&proto_gre_net_ops);
	340	}
	341
	342	module_init(nf_ct_proto_gre_init);
	343	module_exit(nf_ct_proto_gre_fini);
	344
	345	MODULE_LICENSE("GPL");