[linux-2.6-block.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 <net/netfilter/nf_conntrack_timeout.h>
#include <linux/netfilter/nf_conntrack_proto_gre.h>
#include <linux/netfilter/nf_conntrack_pptp.h>

static const 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;

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 */

/* 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,
		      struct sk_buff *skb,
		      unsigned int dataoff,
		      enum ip_conntrack_info ctinfo,
		      const struct nf_hook_state *state)
{
	if (state->pf != NFPROTO_IPV4)
		return -NF_ACCEPT;

	if (!nf_ct_is_confirmed(ct)) {
		unsigned int *timeouts = nf_ct_timeout_lookup(ct);

		if (!timeouts)
			timeouts = gre_get_timeouts(nf_ct_net(ct));

		/* 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];
	}

	/* 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 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);
}

#ifdef CONFIG_NF_CONNTRACK_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);

	if (!timeouts)
		timeouts = gre_get_timeouts(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_CONNTRACK_TIMEOUT */

static int gre_init_net(struct net *net)
{
	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 const struct nf_conntrack_l4proto nf_conntrack_l4proto_gre4 = {
	.l4proto	 = IPPROTO_GRE,
	.pkt_to_tuple	 = gre_pkt_to_tuple,
#ifdef CONFIG_NF_CONNTRACK_PROCFS
	.print_conntrack = gre_print_conntrack,
#endif
	.packet		 = gre_packet,
	.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
#ifdef CONFIG_NF_CONNTRACK_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_CONNTRACK_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;

	BUILD_BUG_ON(offsetof(struct netns_proto_gre, nf) != 0);

	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
f09943fe PM	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	*
f229f6ce	24	* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
f09943fe PM	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>
3bb0d1c0	33	#include <linux/netdevice.h>
f09943fe	34	#include <linux/skbuff.h>
5a0e3ad6	35	#include <linux/slab.h>
3bb0d1c0 AD	36	#include <net/dst.h>
	37	#include <net/net_namespace.h>
	38	#include <net/netns/generic.h>
f09943fe PM	39	#include <net/netfilter/nf_conntrack_l4proto.h>
	40	#include <net/netfilter/nf_conntrack_helper.h>
	41	#include <net/netfilter/nf_conntrack_core.h>
c779e849	42	#include <net/netfilter/nf_conntrack_timeout.h>
f09943fe PM	43	#include <linux/netfilter/nf_conntrack_proto_gre.h>
	44	#include <linux/netfilter/nf_conntrack_pptp.h>
	45
2c9e8637	46	static const unsigned int gre_timeouts[GRE_CT_MAX] = {
b888341c PNA	47	[GRE_CT_UNREPLIED] = 30*HZ,
	48	[GRE_CT_REPLIED] = 180*HZ,
	49	};
f09943fe	50
c7d03a00	51	static unsigned int proto_gre_net_id __read_mostly;
f09943fe	52
4f71d80f G	53	static inline struct netns_proto_gre gre_pernet(struct net net)
	54	{
	55	return net_generic(net, proto_gre_net_id);
	56	}
	57
8142b227	58	static void nf_ct_gre_keymap_flush(struct net *net)
f09943fe	59	{
4f71d80f	60	struct netns_proto_gre *net_gre = gre_pernet(net);
51807e91	61	struct nf_ct_gre_keymap km, tmp;
f09943fe	62
3bb0d1c0 AD	63	write_lock_bh(&net_gre->keymap_lock);
3bb0d1c0 AD	64	list_for_each_entry_safe(km, tmp, &net_gre->keymap_list, list) {
51807e91 AD	65	list_del(&km->list);
51807e91 AD	66	kfree(km);
f09943fe	67	}
3bb0d1c0	68	write_unlock_bh(&net_gre->keymap_lock);
f09943fe	69	}
f09943fe PM	70
	71	static inline int gre_key_cmpfn(const struct nf_ct_gre_keymap *km,
	72	const struct nf_conntrack_tuple *t)
	73	{
	74	return km->tuple.src.l3num == t->src.l3num &&
	75	!memcmp(&km->tuple.src.u3, &t->src.u3, sizeof(t->src.u3)) &&
	76	!memcmp(&km->tuple.dst.u3, &t->dst.u3, sizeof(t->dst.u3)) &&
	77	km->tuple.dst.protonum == t->dst.protonum &&
	78	km->tuple.dst.u.all == t->dst.u.all;
	79	}
	80
	81	/* look up the source key for a given tuple */
3bb0d1c0	82	static __be16 gre_keymap_lookup(struct net net, struct nf_conntrack_tuple t)
f09943fe	83	{
4f71d80f	84	struct netns_proto_gre *net_gre = gre_pernet(net);
f09943fe PM	85	struct nf_ct_gre_keymap *km;
	86	__be16 key = 0;
	87
3bb0d1c0 AD	88	read_lock_bh(&net_gre->keymap_lock);
3bb0d1c0 AD	89	list_for_each_entry(km, &net_gre->keymap_list, list) {
f09943fe PM	90	if (gre_key_cmpfn(km, t)) {
	91	key = km->tuple.src.u.gre.key;
	92	break;
	93	}
	94	}
3bb0d1c0	95	read_unlock_bh(&net_gre->keymap_lock);
f09943fe	96
0d53778e	97	pr_debug("lookup src key 0x%x for ", key);
3c9fba65	98	nf_ct_dump_tuple(t);
f09943fe PM	99
	100	return key;
	101	}
	102
	103	/* add a single keymap entry, associate with specified master ct */
	104	int nf_ct_gre_keymap_add(struct nf_conn *ct, enum ip_conntrack_dir dir,
	105	struct nf_conntrack_tuple *t)
	106	{
3bb0d1c0	107	struct net *net = nf_ct_net(ct);
4f71d80f	108	struct netns_proto_gre *net_gre = gre_pernet(net);
1afc5679	109	struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
f09943fe PM	110	struct nf_ct_gre_keymap *kmp, km;
f09943fe PM	111
1afc5679	112	kmp = &ct_pptp_info->keymap[dir];
f09943fe PM	113	if (*kmp) {
f09943fe PM	114	/* check whether it's a retransmission */
3bb0d1c0 AD	115	read_lock_bh(&net_gre->keymap_lock);
3bb0d1c0 AD	116	list_for_each_entry(km, &net_gre->keymap_list, list) {
887464a4	117	if (gre_key_cmpfn(km, t) && km == *kmp) {
3bb0d1c0	118	read_unlock_bh(&net_gre->keymap_lock);
f09943fe	119	return 0;
887464a4	120	}
f09943fe	121	}
3bb0d1c0	122	read_unlock_bh(&net_gre->keymap_lock);
0d53778e PM	123	pr_debug("trying to override keymap_%s for ct %p\n",
0d53778e PM	124	dir == IP_CT_DIR_REPLY ? "reply" : "orig", ct);
f09943fe PM	125	return -EEXIST;
	126	}
	127
	128	km = kmalloc(sizeof(*km), GFP_ATOMIC);
	129	if (!km)
	130	return -ENOMEM;
	131	memcpy(&km->tuple, t, sizeof(*t));
	132	*kmp = km;
	133
0d53778e	134	pr_debug("adding new entry %p: ", km);
3c9fba65	135	nf_ct_dump_tuple(&km->tuple);
f09943fe	136
3bb0d1c0 AD	137	write_lock_bh(&net_gre->keymap_lock);
	138	list_add_tail(&km->list, &net_gre->keymap_list);
	139	write_unlock_bh(&net_gre->keymap_lock);
f09943fe PM	140
	141	return 0;
	142	}
	143	EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_add);
	144
	145	/* destroy the keymap entries associated with specified master ct */
	146	void nf_ct_gre_keymap_destroy(struct nf_conn *ct)
	147	{
3bb0d1c0	148	struct net *net = nf_ct_net(ct);
4f71d80f	149	struct netns_proto_gre *net_gre = gre_pernet(net);
1afc5679	150	struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
f09943fe PM	151	enum ip_conntrack_dir dir;
f09943fe PM	152
0d53778e	153	pr_debug("entering for ct %p\n", ct);
f09943fe	154
3bb0d1c0	155	write_lock_bh(&net_gre->keymap_lock);
f09943fe	156	for (dir = IP_CT_DIR_ORIGINAL; dir < IP_CT_DIR_MAX; dir++) {
1afc5679	157	if (ct_pptp_info->keymap[dir]) {
0d53778e	158	pr_debug("removing %p from list\n",
1afc5679 PNA	159	ct_pptp_info->keymap[dir]);
	160	list_del(&ct_pptp_info->keymap[dir]->list);
	161	kfree(ct_pptp_info->keymap[dir]);
	162	ct_pptp_info->keymap[dir] = NULL;
f09943fe PM	163	}
f09943fe PM	164	}
3bb0d1c0	165	write_unlock_bh(&net_gre->keymap_lock);
f09943fe PM	166	}
	167	EXPORT_SYMBOL_GPL(nf_ct_gre_keymap_destroy);
	168
	169	/* PUBLIC CONNTRACK PROTO HELPER FUNCTIONS */
	170
f09943fe	171	/* gre hdr info to tuple */
09f263cd	172	static bool gre_pkt_to_tuple(const struct sk_buff *skb, unsigned int dataoff,
a31f1adc	173	struct net net, struct nf_conntrack_tuple tuple)
f09943fe	174	{
c579a9e7 GF	175	const struct pptp_gre_header *pgrehdr;
c579a9e7 GF	176	struct pptp_gre_header _pgrehdr;
f09943fe	177	__be16 srckey;
c579a9e7 GF	178	const struct gre_base_hdr *grehdr;
c579a9e7 GF	179	struct gre_base_hdr _grehdr;
f09943fe PM	180
	181	/* first only delinearize old RFC1701 GRE header */
	182	grehdr = skb_header_pointer(skb, dataoff, sizeof(_grehdr), &_grehdr);
c579a9e7	183	if (!grehdr \|\| (grehdr->flags & GRE_VERSION) != GRE_VERSION_1) {
f09943fe PM	184	/* try to behave like "nf_conntrack_proto_generic" */
	185	tuple->src.u.all = 0;
	186	tuple->dst.u.all = 0;
09f263cd	187	return true;
f09943fe PM	188	}
	189
	190	/* PPTP header is variable length, only need up to the call_id field */
	191	pgrehdr = skb_header_pointer(skb, dataoff, 8, &_pgrehdr);
	192	if (!pgrehdr)
09f263cd	193	return true;
f09943fe	194
ecc6569f	195	if (grehdr->protocol != GRE_PROTO_PPP) {
c579a9e7	196	pr_debug("Unsupported GRE proto(0x%x)\n", ntohs(grehdr->protocol));
09f263cd	197	return false;
f09943fe PM	198	}
	199
	200	tuple->dst.u.gre.key = pgrehdr->call_id;
3bb0d1c0	201	srckey = gre_keymap_lookup(net, tuple);
f09943fe PM	202	tuple->src.u.gre.key = srckey;
f09943fe PM	203
09f263cd	204	return true;
f09943fe PM	205	}
f09943fe PM	206
ea48cc83	207	#ifdef CONFIG_NF_CONNTRACK_PROCFS
f09943fe	208	/* print private data for conntrack */
37246a58	209	static void gre_print_conntrack(struct seq_file s, struct nf_conn ct)
f09943fe	210	{
37246a58 SRRH	211	seq_printf(s, "timeout=%u, stream_timeout=%u ",
	212	(ct->proto.gre.timeout / HZ),
	213	(ct->proto.gre.stream_timeout / HZ));
f09943fe	214	}
ea48cc83	215	#endif
f09943fe	216
2c8503f5 PNA	217	static unsigned int gre_get_timeouts(struct net net)
2c8503f5 PNA	218	{
4f71d80f	219	return gre_pernet(net)->gre_timeouts;
2c8503f5 PNA	220	}
2c8503f5 PNA	221
f09943fe PM	222	/* Returns verdict for packet, and may modify conntrack */
f09943fe PM	223	static int gre_packet(struct nf_conn *ct,
83d213fd	224	struct sk_buff *skb,
f09943fe	225	unsigned int dataoff,
93e66024 FW	226	enum ip_conntrack_info ctinfo,
93e66024 FW	227	const struct nf_hook_state *state)
f09943fe	228	{
dd2934a9 FW	229	if (state->pf != NFPROTO_IPV4)
	230	return -NF_ACCEPT;
	231
9976fc6e FW	232	if (!nf_ct_is_confirmed(ct)) {
	233	unsigned int *timeouts = nf_ct_timeout_lookup(ct);
	234
	235	if (!timeouts)
	236	timeouts = gre_get_timeouts(nf_ct_net(ct));
	237
	238	/* initialize to sane value. Ideally a conntrack helper
	239	* (e.g. in case of pptp) is increasing them */
	240	ct->proto.gre.stream_timeout = timeouts[GRE_CT_REPLIED];
	241	ct->proto.gre.timeout = timeouts[GRE_CT_UNREPLIED];
	242	}
	243
f09943fe PM	244	/* If we've seen traffic both ways, this is a GRE connection.
	245	* Extend timeout. */
	246	if (ct->status & IPS_SEEN_REPLY) {
	247	nf_ct_refresh_acct(ct, ctinfo, skb,
	248	ct->proto.gre.stream_timeout);
	249	/* Also, more likely to be important, and not a probe. */
98d9ae84 FW	250	if (!test_and_set_bit(IPS_ASSURED_BIT, &ct->status))
98d9ae84 FW	251	nf_conntrack_event_cache(IPCT_ASSURED, ct);
f09943fe PM	252	} else
	253	nf_ct_refresh_acct(ct, ctinfo, skb,
	254	ct->proto.gre.timeout);
	255
	256	return NF_ACCEPT;
	257	}
	258
f09943fe PM	259	/* Called when a conntrack entry has already been removed from the hashes
	260	* and is about to be deleted from memory */
	261	static void gre_destroy(struct nf_conn *ct)
	262	{
	263	struct nf_conn *master = ct->master;
0d53778e	264	pr_debug(" entering\n");
f09943fe PM	265
f09943fe PM	266	if (!master)
0d53778e	267	pr_debug("no master !?!\n");
f09943fe PM	268	else
	269	nf_ct_gre_keymap_destroy(master);
	270	}
	271
a874752a	272	#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
50978462 PNA	273
	274	#include <linux/netfilter/nfnetlink.h>
	275	#include <linux/netfilter/nfnetlink_cttimeout.h>
	276
8264deb8 G	277	static int gre_timeout_nlattr_to_obj(struct nlattr *tb[],
8264deb8 G	278	struct net net, void data)
50978462 PNA	279	{
50978462 PNA	280	unsigned int *timeouts = data;
8264deb8	281	struct netns_proto_gre *net_gre = gre_pernet(net);
50978462	282
c779e849 FW	283	if (!timeouts)
c779e849 FW	284	timeouts = gre_get_timeouts(net);
50978462	285	/* set default timeouts for GRE. */
8264deb8 G	286	timeouts[GRE_CT_UNREPLIED] = net_gre->gre_timeouts[GRE_CT_UNREPLIED];
8264deb8 G	287	timeouts[GRE_CT_REPLIED] = net_gre->gre_timeouts[GRE_CT_REPLIED];
50978462 PNA	288
	289	if (tb[CTA_TIMEOUT_GRE_UNREPLIED]) {
	290	timeouts[GRE_CT_UNREPLIED] =
	291	ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_UNREPLIED])) * HZ;
	292	}
	293	if (tb[CTA_TIMEOUT_GRE_REPLIED]) {
	294	timeouts[GRE_CT_REPLIED] =
	295	ntohl(nla_get_be32(tb[CTA_TIMEOUT_GRE_REPLIED])) * HZ;
	296	}
	297	return 0;
	298	}
	299
	300	static int
	301	gre_timeout_obj_to_nlattr(struct sk_buff skb, const void data)
	302	{
	303	const unsigned int *timeouts = data;
	304
242ddfc0 DM	305	if (nla_put_be32(skb, CTA_TIMEOUT_GRE_UNREPLIED,
	306	htonl(timeouts[GRE_CT_UNREPLIED] / HZ)) \|\|
	307	nla_put_be32(skb, CTA_TIMEOUT_GRE_REPLIED,
	308	htonl(timeouts[GRE_CT_REPLIED] / HZ)))
	309	goto nla_put_failure;
50978462 PNA	310	return 0;
	311
	312	nla_put_failure:
	313	return -ENOSPC;
	314	}
	315
	316	static const struct nla_policy
	317	gre_timeout_nla_policy[CTA_TIMEOUT_GRE_MAX+1] = {
	318	[CTA_TIMEOUT_GRE_UNREPLIED] = { .type = NLA_U32 },
	319	[CTA_TIMEOUT_GRE_REPLIED] = { .type = NLA_U32 },
	320	};
a874752a	321	#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
50978462	322
ca2ca6e1	323	static int gre_init_net(struct net *net)
4f71d80f G	324	{
	325	struct netns_proto_gre *net_gre = gre_pernet(net);
	326	int i;
	327
	328	rwlock_init(&net_gre->keymap_lock);
	329	INIT_LIST_HEAD(&net_gre->keymap_list);
	330	for (i = 0; i < GRE_CT_MAX; i++)
	331	net_gre->gre_timeouts[i] = gre_timeouts[i];
	332
	333	return 0;
	334	}
	335
f09943fe	336	/* protocol helper struct */
9dae47ab	337	static const struct nf_conntrack_l4proto nf_conntrack_l4proto_gre4 = {
f09943fe	338	.l4proto = IPPROTO_GRE,
f09943fe	339	.pkt_to_tuple = gre_pkt_to_tuple,
ea48cc83	340	#ifdef CONFIG_NF_CONNTRACK_PROCFS
f09943fe	341	.print_conntrack = gre_print_conntrack,
ea48cc83	342	#endif
f09943fe	343	.packet = gre_packet,
f09943fe PM	344	.destroy = gre_destroy,
f09943fe PM	345	.me = THIS_MODULE,
c0cd1156	346	#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
fdf70832	347	.tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
a400c30e	348	.nlattr_tuple_size = nf_ct_port_nlattr_tuple_size,
fdf70832	349	.nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
f73e924c	350	.nla_policy = nf_ct_port_nla_policy,
f09943fe	351	#endif
a874752a	352	#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
50978462 PNA	353	.ctnl_timeout = {
	354	.nlattr_to_obj = gre_timeout_nlattr_to_obj,
	355	.obj_to_nlattr = gre_timeout_obj_to_nlattr,
	356	.nlattr_max = CTA_TIMEOUT_GRE_MAX,
	357	.obj_size = sizeof(unsigned int) * GRE_CT_MAX,
	358	.nla_policy = gre_timeout_nla_policy,
	359	},
a874752a	360	#endif /* CONFIG_NF_CONNTRACK_TIMEOUT */
4f71d80f G	361	.net_id = &proto_gre_net_id,
4f71d80f G	362	.init_net = gre_init_net,
f09943fe PM	363	};
f09943fe PM	364
3bb0d1c0 AD	365	static int proto_gre_net_init(struct net *net)
3bb0d1c0 AD	366	{
4f71d80f	367	int ret = 0;
0e54d217 DC	368
	369	ret = nf_ct_l4proto_pernet_register_one(net,
	370	&nf_conntrack_l4proto_gre4);
4f71d80f	371	if (ret < 0)
c296bb4d	372	pr_err("nf_conntrack_gre4: pernet registration failed.\n");
4f71d80f	373	return ret;
3bb0d1c0 AD	374	}
	375
	376	static void proto_gre_net_exit(struct net *net)
	377	{
0e54d217	378	nf_ct_l4proto_pernet_unregister_one(net, &nf_conntrack_l4proto_gre4);
3bb0d1c0	379	nf_ct_gre_keymap_flush(net);
3bb0d1c0 AD	380	}
	381
	382	static struct pernet_operations proto_gre_net_ops = {
	383	.init = proto_gre_net_init,
	384	.exit = proto_gre_net_exit,
e8d02885 EB	385	.id = &proto_gre_net_id,
e8d02885 EB	386	.size = sizeof(struct netns_proto_gre),
3bb0d1c0 AD	387	};
3bb0d1c0 AD	388
f09943fe PM	389	static int __init nf_ct_proto_gre_init(void)
f09943fe PM	390	{
c296bb4d G	391	int ret;
c296bb4d G	392
89259088 FW	393	BUILD_BUG_ON(offsetof(struct netns_proto_gre, nf) != 0);
89259088 FW	394
c296bb4d G	395	ret = register_pernet_subsys(&proto_gre_net_ops);
	396	if (ret < 0)
	397	goto out_pernet;
0e54d217	398	ret = nf_ct_l4proto_register_one(&nf_conntrack_l4proto_gre4);
0d98da5d G	399	if (ret < 0)
	400	goto out_gre4;
	401
c296bb4d	402	return 0;
c296bb4d	403	out_gre4:
0d98da5d G	404	unregister_pernet_subsys(&proto_gre_net_ops);
0d98da5d G	405	out_pernet:
c296bb4d	406	return ret;
f09943fe PM	407	}
f09943fe PM	408
56bc0f96	409	static void __exit nf_ct_proto_gre_fini(void)
f09943fe	410	{
0e54d217	411	nf_ct_l4proto_unregister_one(&nf_conntrack_l4proto_gre4);
e8d02885	412	unregister_pernet_subsys(&proto_gre_net_ops);
f09943fe PM	413	}
	414
	415	module_init(nf_ct_proto_gre_init);
	416	module_exit(nf_ct_proto_gre_fini);
	417
	418	MODULE_LICENSE("GPL");