[mirror_ubuntu-bionic-kernel.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/)
 *
 * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
 */

#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 <linux/slab.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>

enum grep_conntrack {
	GRE_CT_UNREPLIED,
	GRE_CT_REPLIED,
	GRE_CT_MAX
};

static unsigned int gre_timeouts[GRE_CT_MAX] = {
	[GRE_CT_UNREPLIED]	= 30*HZ,
	[GRE_CT_REPLIED]	= 180*HZ,
};

static unsigned int proto_gre_net_id __read_mostly;
struct netns_proto_gre {
	struct nf_proto_net	nf;
	rwlock_t		keymap_lock;
	struct list_head	keymap_list;
	unsigned int		gre_timeouts[GRE_CT_MAX];
};

static inline struct netns_proto_gre *gre_pernet(struct net *net)
{
	return net_generic(net, proto_gre_net_id);
}

static void nf_ct_gre_keymap_flush(struct net *net)
{
	struct netns_proto_gre *net_gre = gre_pernet(net);
	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);
}

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 = gre_pernet(net);
	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 = gre_pernet(net);
	struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
	struct nf_ct_gre_keymap **kmp, *km;

	kmp = &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 = gre_pernet(net);
	struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(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 (ct_pptp_info->keymap[dir]) {
			pr_debug("removing %p from list\n",
				 ct_pptp_info->keymap[dir]);
			list_del(&ct_pptp_info->keymap[dir]->list);
			kfree(ct_pptp_info->keymap[dir]);
			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 net *net, struct nf_conntrack_tuple *tuple)
{
	const struct pptp_gre_header *pgrehdr;
	struct pptp_gre_header _pgrehdr;
	__be16 srckey;
	const struct gre_base_hdr *grehdr;
	struct gre_base_hdr _grehdr;

	/* first only delinearize old RFC1701 GRE header */
	grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
	if (!grehdr || (grehdr->flags & GRE_VERSION) != GRE_VERSION_1) {
		/* 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 (grehdr->protocol != GRE_PROTO_PPP) {
		pr_debug("Unsupported GRE proto(0x%x)\n", ntohs(grehdr->protocol));
		return false;
	}

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

	return true;
}

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

static unsigned int *gre_get_timeouts(struct net *net)
{
	return gre_pernet(net)->gre_timeouts;
}

/* 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,
		      unsigned int *timeouts)
{
	/* 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. */
		if (!test_and_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, unsigned int *timeouts)
{
	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 = timeouts[GRE_CT_REPLIED];
	ct->proto.gre.timeout = timeouts[GRE_CT_UNREPLIED];

	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);
}

#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)

#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_cttimeout.h>

static int gre_timeout_nlattr_to_obj(struct nlattr *tb[],
				     struct net *net, void *data)
{
	unsigned int *timeouts = data;
	struct netns_proto_gre *net_gre = gre_pernet(net);

	/* set default timeouts for GRE. */
	timeouts[GRE_CT_UNREPLIED] = net_gre->gre_timeouts[GRE_CT_UNREPLIED];
	timeouts[GRE_CT_REPLIED] = net_gre->gre_timeouts[GRE_CT_REPLIED];

	if (tb[CTA_TIMEOUT_GRE_UNREPLIED]) {
		timeouts[GRE_CT_UNREPLIED] =
			ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_UNREPLIED])) * HZ;
	}
	if (tb[CTA_TIMEOUT_GRE_REPLIED]) {
		timeouts[GRE_CT_REPLIED] =
			ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_REPLIED])) * HZ;
	}
	return 0;
}

static int
gre_timeout_obj_to_nlattr(struct sk_buff *skb, const void *data)
{
	const unsigned int *timeouts = data;

	if (nla_put_be32(skb, CTA_TIMEOUT_GRE_UNREPLIED,
			 htonl(timeouts[GRE_CT_UNREPLIED] / HZ)) ||
	    nla_put_be32(skb, CTA_TIMEOUT_GRE_REPLIED,
			 htonl(timeouts[GRE_CT_REPLIED] / HZ)))
		goto nla_put_failure;
	return 0;

nla_put_failure:
	return -ENOSPC;
}

static const struct nla_policy
gre_timeout_nla_policy[CTA_TIMEOUT_GRE_MAX+1] = {
	[CTA_TIMEOUT_GRE_UNREPLIED]	= { .type = NLA_U32 },
	[CTA_TIMEOUT_GRE_REPLIED]	= { .type = NLA_U32 },
};
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */

static int gre_init_net(struct net *net, u_int16_t proto)
{
	struct netns_proto_gre *net_gre = gre_pernet(net);
	int i;

	rwlock_init(&net_gre->keymap_lock);
	INIT_LIST_HEAD(&net_gre->keymap_list);
	for (i = 0; i < GRE_CT_MAX; i++)
		net_gre->gre_timeouts[i] = gre_timeouts[i];

	return 0;
}

/* protocol helper struct */
static struct nf_conntrack_l4proto nf_conntrack_l4proto_gre4 __read_mostly = {
	.l3proto	 = AF_INET,
	.l4proto	 = IPPROTO_GRE,
	.pkt_to_tuple	 = gre_pkt_to_tuple,
	.invert_tuple	 = gre_invert_tuple,
#ifdef CONFIG_NF_CONNTRACK_PROCFS
	.print_conntrack = gre_print_conntrack,
#endif
	.get_timeouts    = gre_get_timeouts,
	.packet		 = gre_packet,
	.new		 = gre_new,
	.destroy	 = gre_destroy,
	.me 		 = THIS_MODULE,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
	.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
#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
	.ctnl_timeout    = {
		.nlattr_to_obj	= gre_timeout_nlattr_to_obj,
		.obj_to_nlattr	= gre_timeout_obj_to_nlattr,
		.nlattr_max	= CTA_TIMEOUT_GRE_MAX,
		.obj_size	= sizeof(unsigned int) * GRE_CT_MAX,
		.nla_policy	= gre_timeout_nla_policy,
	},
#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
	.net_id		= &proto_gre_net_id,
	.init_net	= gre_init_net,
};

static int proto_gre_net_init(struct net *net)
{
	int ret = 0;

	ret = nf_ct_l4proto_pernet_register_one(net,
						&nf_conntrack_l4proto_gre4);
	if (ret < 0)
		pr_err("nf_conntrack_gre4: pernet registration failed.\n");
	return ret;
}

static void proto_gre_net_exit(struct net *net)
{
	nf_ct_l4proto_pernet_unregister_one(net, &nf_conntrack_l4proto_gre4);
	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 ret;

	ret = register_pernet_subsys(&proto_gre_net_ops);
	if (ret < 0)
		goto out_pernet;
	ret = nf_ct_l4proto_register_one(&nf_conntrack_l4proto_gre4);
	if (ret < 0)
		goto out_gre4;

	return 0;
out_gre4:
	unregister_pernet_subsys(&proto_gre_net_ops);
out_pernet:
	return ret;
}

static void __exit nf_ct_proto_gre_fini(void)
{
	nf_ct_l4proto_unregister_one(&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	* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
	25	*/
	26
	27	#include <linux/module.h>
	28	#include <linux/types.h>
	29	#include <linux/timer.h>
	30	#include <linux/list.h>
	31	#include <linux/seq_file.h>
	32	#include <linux/in.h>
	33	#include <linux/netdevice.h>
	34	#include <linux/skbuff.h>
	35	#include <linux/slab.h>
	36	#include <net/dst.h>
	37	#include <net/net_namespace.h>
	38	#include <net/netns/generic.h>
	39	#include <net/netfilter/nf_conntrack_l4proto.h>
	40	#include <net/netfilter/nf_conntrack_helper.h>
	41	#include <net/netfilter/nf_conntrack_core.h>
	42	#include <linux/netfilter/nf_conntrack_proto_gre.h>
	43	#include <linux/netfilter/nf_conntrack_pptp.h>
	44
	45	enum grep_conntrack {
	46	GRE_CT_UNREPLIED,
	47	GRE_CT_REPLIED,
	48	GRE_CT_MAX
	49	};
	50
	51	static unsigned int gre_timeouts[GRE_CT_MAX] = {
	52	[GRE_CT_UNREPLIED] = 30*HZ,
	53	[GRE_CT_REPLIED] = 180*HZ,
	54	};
	55
	56	static unsigned int proto_gre_net_id __read_mostly;
	57	struct netns_proto_gre {
	58	struct nf_proto_net nf;
	59	rwlock_t keymap_lock;
	60	struct list_head keymap_list;
	61	unsigned int gre_timeouts[GRE_CT_MAX];
	62	};
	63
	64	static inline struct netns_proto_gre gre_pernet(struct net net)
	65	{
	66	return net_generic(net, proto_gre_net_id);
	67	}
	68
	69	static void nf_ct_gre_keymap_flush(struct net *net)
	70	{
	71	struct netns_proto_gre *net_gre = gre_pernet(net);
	72	struct nf_ct_gre_keymap km, tmp;
	73
	74	write_lock_bh(&net_gre->keymap_lock);
	75	list_for_each_entry_safe(km, tmp, &net_gre->keymap_list, list) {
	76	list_del(&km->list);
	77	kfree(km);
	78	}
	79	write_unlock_bh(&net_gre->keymap_lock);
	80	}
	81
	82	static inline int gre_key_cmpfn(const struct nf_ct_gre_keymap *km,
	83	const struct nf_conntrack_tuple *t)
	84	{
	85	return km->tuple.src.l3num == t->src.l3num &&
	86	!memcmp(&km->tuple.src.u3, &t->src.u3, sizeof(t->src.u3)) &&
	87	!memcmp(&km->tuple.dst.u3, &t->dst.u3, sizeof(t->dst.u3)) &&
	88	km->tuple.dst.protonum == t->dst.protonum &&
	89	km->tuple.dst.u.all == t->dst.u.all;
	90	}
	91
	92	/* look up the source key for a given tuple */
	93	static __be16 gre_keymap_lookup(struct net net, struct nf_conntrack_tuple t)
	94	{
	95	struct netns_proto_gre *net_gre = gre_pernet(net);
	96	struct nf_ct_gre_keymap *km;
	97	__be16 key = 0;
	98
	99	read_lock_bh(&net_gre->keymap_lock);
	100	list_for_each_entry(km, &net_gre->keymap_list, list) {
	101	if (gre_key_cmpfn(km, t)) {
	102	key = km->tuple.src.u.gre.key;
	103	break;
	104	}
	105	}
	106	read_unlock_bh(&net_gre->keymap_lock);
	107
	108	pr_debug("lookup src key 0x%x for ", key);
	109	nf_ct_dump_tuple(t);
	110
	111	return key;
	112	}
	113
	114	/* add a single keymap entry, associate with specified master ct */
	115	int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir,
	116	struct nf_conntrack_tuple *t)
	117	{
	118	struct net *net = nf_ct_net(ct);
	119	struct netns_proto_gre *net_gre = gre_pernet(net);
	120	struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
	121	struct nf_ct_gre_keymap *kmp, km;
	122
	123	kmp = &ct_pptp_info->keymap[dir];
	124	if (*kmp) {
	125	/* check whether it's a retransmission */
	126	read_lock_bh(&net_gre->keymap_lock);
	127	list_for_each_entry(km, &net_gre->keymap_list, list) {
	128	if (gre_key_cmpfn(km, t) && km == *kmp) {
	129	read_unlock_bh(&net_gre->keymap_lock);
	130	return 0;
	131	}
	132	}
	133	read_unlock_bh(&net_gre->keymap_lock);
	134	pr_debug("trying to override keymap_%s for ct %p\n",
	135	dir == IP_CT_DIR_REPLY ? "reply" : "orig", ct);
	136	return -EEXIST;
	137	}
	138
	139	km = kmalloc(sizeof(*km), GFP_ATOMIC);
	140	if (!km)
	141	return -ENOMEM;
	142	memcpy(&km->tuple, t, sizeof(*t));
	143	*kmp = km;
	144
	145	pr_debug("adding new entry %p: ", km);
	146	nf_ct_dump_tuple(&km->tuple);
	147
	148	write_lock_bh(&net_gre->keymap_lock);
	149	list_add_tail(&km->list, &net_gre->keymap_list);
	150	write_unlock_bh(&net_gre->keymap_lock);
	151
	152	return 0;
	153	}
	154	EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_add);
	155
	156	/* destroy the keymap entries associated with specified master ct */
	157	void nf_ct_gre_keymap_destroy(struct nf_conn *ct)
	158	{
	159	struct net *net = nf_ct_net(ct);
	160	struct netns_proto_gre *net_gre = gre_pernet(net);
	161	struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
	162	enum ip_conntrack_dir dir;
	163
	164	pr_debug("entering for ct %p\n", ct);
	165
	166	write_lock_bh(&net_gre->keymap_lock);
	167	for (dir = IP_CT_DIR_ORIGINAL; dir < IP_CT_DIR_MAX; dir++) {
	168	if (ct_pptp_info->keymap[dir]) {
	169	pr_debug("removing %p from list\n",
	170	ct_pptp_info->keymap[dir]);
	171	list_del(&ct_pptp_info->keymap[dir]->list);
	172	kfree(ct_pptp_info->keymap[dir]);
	173	ct_pptp_info->keymap[dir] = NULL;
	174	}
	175	}
	176	write_unlock_bh(&net_gre->keymap_lock);
	177	}
	178	EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_destroy);
	179
	180	/* PUBLIC CONNTRACK PROTO HELPER FUNCTIONS */
	181
	182	/* invert gre part of tuple */
	183	static bool gre_invert_tuple(struct nf_conntrack_tuple *tuple,
	184	const struct nf_conntrack_tuple *orig)
	185	{
	186	tuple->dst.u.gre.key = orig->src.u.gre.key;
	187	tuple->src.u.gre.key = orig->dst.u.gre.key;
	188	return true;
	189	}
	190
	191	/* gre hdr info to tuple */
	192	static bool gre_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
	193	struct net net, struct nf_conntrack_tuple tuple)
	194	{
	195	const struct pptp_gre_header *pgrehdr;
	196	struct pptp_gre_header _pgrehdr;
	197	__be16 srckey;
	198	const struct gre_base_hdr *grehdr;
	199	struct gre_base_hdr _grehdr;
	200
	201	/* first only delinearize old RFC1701 GRE header */
	202	grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
	203	if (!grehdr \|\| (grehdr->flags & GRE_VERSION) != GRE_VERSION_1) {
	204	/* try to behave like "nf_conntrack_proto_generic" */
	205	tuple->src.u.all = 0;
	206	tuple->dst.u.all = 0;
	207	return true;
	208	}
	209
	210	/* PPTP header is variable length, only need up to the call_id field */
	211	pgrehdr = skb_header_pointer(skb, dataoff, 8, &_pgrehdr);
	212	if (!pgrehdr)
	213	return true;
	214
	215	if (grehdr->protocol != GRE_PROTO_PPP) {
	216	pr_debug("Unsupported GRE proto(0x%x)\n", ntohs(grehdr->protocol));
	217	return false;
	218	}
	219
	220	tuple->dst.u.gre.key = pgrehdr->call_id;
	221	srckey = gre_keymap_lookup(net, tuple);
	222	tuple->src.u.gre.key = srckey;
	223
	224	return true;
	225	}
	226
	227	#ifdef CONFIG_NF_CONNTRACK_PROCFS
	228	/* print private data for conntrack */
	229	static void gre_print_conntrack(struct seq_file s, struct nf_conn ct)
	230	{
	231	seq_printf(s, "timeout=%u, stream_timeout=%u ",
	232	(ct->proto.gre.timeout / HZ),
	233	(ct->proto.gre.stream_timeout / HZ));
	234	}
	235	#endif
	236
	237	static unsigned int gre_get_timeouts(struct net net)
	238	{
	239	return gre_pernet(net)->gre_timeouts;
	240	}
	241
	242	/* Returns verdict for packet, and may modify conntrack */
	243	static int gre_packet(struct nf_conn *ct,
	244	const struct sk_buff *skb,
	245	unsigned int dataoff,
	246	enum ip_conntrack_info ctinfo,
	247	unsigned int *timeouts)
	248	{
	249	/* If we've seen traffic both ways, this is a GRE connection.
	250	* Extend timeout. */
	251	if (ct->status & IPS_SEEN_REPLY) {
	252	nf_ct_refresh_acct(ct, ctinfo, skb,
	253	ct->proto.gre.stream_timeout);
	254	/* Also, more likely to be important, and not a probe. */
	255	if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
	256	nf_conntrack_event_cache(IPCT_ASSURED, ct);
	257	} else
	258	nf_ct_refresh_acct(ct, ctinfo, skb,
	259	ct->proto.gre.timeout);
	260
	261	return NF_ACCEPT;
	262	}
	263
	264	/* Called when a new connection for this protocol found. */
	265	static bool gre_new(struct nf_conn ct, const struct sk_buff skb,
	266	unsigned int dataoff, unsigned int *timeouts)
	267	{
	268	pr_debug(": ");
	269	nf_ct_dump_tuple(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
	270
	271	/* initialize to sane value. Ideally a conntrack helper
	272	* (e.g. in case of pptp) is increasing them */
	273	ct->proto.gre.stream_timeout = timeouts[GRE_CT_REPLIED];
	274	ct->proto.gre.timeout = timeouts[GRE_CT_UNREPLIED];
	275
	276	return true;
	277	}
	278
	279	/* Called when a conntrack entry has already been removed from the hashes
	280	* and is about to be deleted from memory */
	281	static void gre_destroy(struct nf_conn *ct)
	282	{
	283	struct nf_conn *master = ct->master;
	284	pr_debug(" entering\n");
	285
	286	if (!master)
	287	pr_debug("no master !?!\n");
	288	else
	289	nf_ct_gre_keymap_destroy(master);
	290	}
	291
	292	#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
	293
	294	#include <linux/netfilter/nfnetlink.h>
	295	#include <linux/netfilter/nfnetlink_cttimeout.h>
	296
	297	static int gre_timeout_nlattr_to_obj(struct nlattr *tb[],
	298	struct net net, void data)
	299	{
	300	unsigned int *timeouts = data;
	301	struct netns_proto_gre *net_gre = gre_pernet(net);
	302
	303	/* set default timeouts for GRE. */
	304	timeouts[GRE_CT_UNREPLIED] = net_gre->gre_timeouts[GRE_CT_UNREPLIED];
	305	timeouts[GRE_CT_REPLIED] = net_gre->gre_timeouts[GRE_CT_REPLIED];
	306
	307	if (tb[CTA_TIMEOUT_GRE_UNREPLIED]) {
	308	timeouts[GRE_CT_UNREPLIED] =
	309	ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_UNREPLIED])) * HZ;
	310	}
	311	if (tb[CTA_TIMEOUT_GRE_REPLIED]) {
	312	timeouts[GRE_CT_REPLIED] =
	313	ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_REPLIED])) * HZ;
	314	}
	315	return 0;
	316	}
	317
	318	static int
	319	gre_timeout_obj_to_nlattr(struct sk_buff skb, const void data)
	320	{
	321	const unsigned int *timeouts = data;
	322
	323	if (nla_put_be32(skb, CTA_TIMEOUT_GRE_UNREPLIED,
	324	htonl(timeouts[GRE_CT_UNREPLIED] / HZ)) \|\|
	325	nla_put_be32(skb, CTA_TIMEOUT_GRE_REPLIED,
	326	htonl(timeouts[GRE_CT_REPLIED] / HZ)))
	327	goto nla_put_failure;
	328	return 0;
	329
	330	nla_put_failure:
	331	return -ENOSPC;
	332	}
	333
	334	static const struct nla_policy
	335	gre_timeout_nla_policy[CTA_TIMEOUT_GRE_MAX+1] = {
	336	[CTA_TIMEOUT_GRE_UNREPLIED] = { .type = NLA_U32 },
	337	[CTA_TIMEOUT_GRE_REPLIED] = { .type = NLA_U32 },
	338	};
	339	#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
	340
	341	static int gre_init_net(struct net *net, u_int16_t proto)
	342	{
	343	struct netns_proto_gre *net_gre = gre_pernet(net);
	344	int i;
	345
	346	rwlock_init(&net_gre->keymap_lock);
	347	INIT_LIST_HEAD(&net_gre->keymap_list);
	348	for (i = 0; i < GRE_CT_MAX; i++)
	349	net_gre->gre_timeouts[i] = gre_timeouts[i];
	350
	351	return 0;
	352	}
	353
	354	/* protocol helper struct */
	355	static struct nf_conntrack_l4proto nf_conntrack_l4proto_gre4 __read_mostly = {
	356	.l3proto = AF_INET,
	357	.l4proto = IPPROTO_GRE,
	358	.pkt_to_tuple = gre_pkt_to_tuple,
	359	.invert_tuple = gre_invert_tuple,
	360	#ifdef CONFIG_NF_CONNTRACK_PROCFS
	361	.print_conntrack = gre_print_conntrack,
	362	#endif
	363	.get_timeouts = gre_get_timeouts,
	364	.packet = gre_packet,
	365	.new = gre_new,
	366	.destroy = gre_destroy,
	367	.me = THIS_MODULE,
	368	#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
	369	.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
	370	.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
	371	.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
	372	.nla_policy = nf_ct_port_nla_policy,
	373	#endif
	374	#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
	375	.ctnl_timeout = {
	376	.nlattr_to_obj = gre_timeout_nlattr_to_obj,
	377	.obj_to_nlattr = gre_timeout_obj_to_nlattr,
	378	.nlattr_max = CTA_TIMEOUT_GRE_MAX,
	379	.obj_size = sizeof(unsigned int) * GRE_CT_MAX,
	380	.nla_policy = gre_timeout_nla_policy,
	381	},
	382	#endif /* CONFIG_NF_CT_NETLINK_TIMEOUT */
	383	.net_id = &proto_gre_net_id,
	384	.init_net = gre_init_net,
	385	};
	386
	387	static int proto_gre_net_init(struct net *net)
	388	{
	389	int ret = 0;
	390
	391	ret = nf_ct_l4proto_pernet_register_one(net,
	392	&nf_conntrack_l4proto_gre4);
	393	if (ret < 0)
	394	pr_err("nf_conntrack_gre4: pernet registration failed.\n");
	395	return ret;
	396	}
	397
	398	static void proto_gre_net_exit(struct net *net)
	399	{
	400	nf_ct_l4proto_pernet_unregister_one(net, &nf_conntrack_l4proto_gre4);
	401	nf_ct_gre_keymap_flush(net);
	402	}
	403
	404	static struct pernet_operations proto_gre_net_ops = {
	405	.init = proto_gre_net_init,
	406	.exit = proto_gre_net_exit,
	407	.id = &proto_gre_net_id,
	408	.size = sizeof(struct netns_proto_gre),
	409	};
	410
	411	static int __init nf_ct_proto_gre_init(void)
	412	{
	413	int ret;
	414
	415	ret = register_pernet_subsys(&proto_gre_net_ops);
	416	if (ret < 0)
	417	goto out_pernet;
	418	ret = nf_ct_l4proto_register_one(&nf_conntrack_l4proto_gre4);
	419	if (ret < 0)
	420	goto out_gre4;
	421
	422	return 0;
	423	out_gre4:
	424	unregister_pernet_subsys(&proto_gre_net_ops);
	425	out_pernet:
	426	return ret;
	427	}
	428
	429	static void __exit nf_ct_proto_gre_fini(void)
	430	{
	431	nf_ct_l4proto_unregister_one(&nf_conntrack_l4proto_gre4);
	432	unregister_pernet_subsys(&proto_gre_net_ops);
	433	}
	434
	435	module_init(nf_ct_proto_gre_init);
	436	module_exit(nf_ct_proto_gre_fini);
	437
	438	MODULE_LICENSE("GPL");