[linux-2.6-block.git] / net / l2tp / l2tp_core.h

/* SPDX-License-Identifier: GPL-2.0-only */
/* L2TP internal definitions.
 *
 * Copyright (c) 2008,2009 Katalix Systems Ltd
 */
#include <linux/refcount.h>

#ifndef _L2TP_CORE_H_
#define _L2TP_CORE_H_

#include <net/dst.h>
#include <net/sock.h>

#ifdef CONFIG_XFRM
#include <net/xfrm.h>
#endif

/* Random numbers used for internal consistency checks of tunnel and session structures */
#define L2TP_TUNNEL_MAGIC	0x42114DDA
#define L2TP_SESSION_MAGIC	0x0C04EB7D

/* Per tunnel session hash table size */
#define L2TP_HASH_BITS	4
#define L2TP_HASH_SIZE	BIT(L2TP_HASH_BITS)

/* System-wide session hash table size */
#define L2TP_HASH_BITS_2	8
#define L2TP_HASH_SIZE_2	BIT(L2TP_HASH_BITS_2)

struct sk_buff;

struct l2tp_stats {
	atomic_long_t		tx_packets;
	atomic_long_t		tx_bytes;
	atomic_long_t		tx_errors;
	atomic_long_t		rx_packets;
	atomic_long_t		rx_bytes;
	atomic_long_t		rx_seq_discards;
	atomic_long_t		rx_oos_packets;
	atomic_long_t		rx_errors;
	atomic_long_t		rx_cookie_discards;
};

struct l2tp_tunnel;

/* L2TP session configuration */
struct l2tp_session_cfg {
	enum l2tp_pwtype	pw_type;
	unsigned int		recv_seq:1;	/* expect receive packets with sequence numbers? */
	unsigned int		send_seq:1;	/* send packets with sequence numbers? */
	unsigned int		lns_mode:1;	/* behave as LNS?
						 * LAC enables sequence numbers under LNS control.
						 */
	u16			l2specific_type; /* Layer 2 specific type */
	u8			cookie[8];	/* optional cookie */
	int			cookie_len;	/* 0, 4 or 8 bytes */
	u8			peer_cookie[8];	/* peer's cookie */
	int			peer_cookie_len; /* 0, 4 or 8 bytes */
	int			reorder_timeout; /* configured reorder timeout (in jiffies) */
	char			*ifname;
};

/* Represents a session (pseudowire) instance.
 * Tracks runtime state including cookies, dataplane packet sequencing, and IO statistics.
 * Is linked into a per-tunnel session hashlist; and in the case of an L2TPv3 session into
 * an additional per-net ("global") hashlist.
 */
#define L2TP_SESSION_NAME_MAX 32
struct l2tp_session {
	int			magic;		/* should be L2TP_SESSION_MAGIC */
	long			dead;

	struct l2tp_tunnel	*tunnel;	/* back pointer to tunnel context */
	u32			session_id;
	u32			peer_session_id;
	u8			cookie[8];
	int			cookie_len;
	u8			peer_cookie[8];
	int			peer_cookie_len;
	u16			l2specific_type;
	u16			hdr_len;
	u32			nr;		/* session NR state (receive) */
	u32			ns;		/* session NR state (send) */
	struct sk_buff_head	reorder_q;	/* receive reorder queue */
	u32			nr_max;		/* max NR. Depends on tunnel */
	u32			nr_window_size;	/* NR window size */
	u32			nr_oos;		/* NR of last OOS packet */
	int			nr_oos_count;	/* for OOS recovery */
	int			nr_oos_count_max;
	struct hlist_node	hlist;		/* hash list node */
	refcount_t		ref_count;

	char			name[L2TP_SESSION_NAME_MAX]; /* for logging */
	char			ifname[IFNAMSIZ];
	unsigned int		recv_seq:1;	/* expect receive packets with sequence numbers? */
	unsigned int		send_seq:1;	/* send packets with sequence numbers? */
	unsigned int		lns_mode:1;	/* behave as LNS?
						 * LAC enables sequence numbers under LNS control.
						 */
	int			reorder_timeout; /* configured reorder timeout (in jiffies) */
	int			reorder_skip;	/* set if skip to next nr */
	enum l2tp_pwtype	pwtype;
	struct l2tp_stats	stats;
	struct hlist_node	global_hlist;	/* global hash list node */

	/* Session receive handler for data packets.
	 * Each pseudowire implementation should implement this callback in order to
	 * handle incoming packets.  Packets are passed to the pseudowire handler after
	 * reordering, if data sequence numbers are enabled for the session.
	 */
	void (*recv_skb)(struct l2tp_session *session, struct sk_buff *skb, int data_len);

	/* Session close handler.
	 * Each pseudowire implementation may implement this callback in order to carry
	 * out pseudowire-specific shutdown actions.
	 * The callback is called by core after unhashing the session and purging its
	 * reorder queue.
	 */
	void (*session_close)(struct l2tp_session *session);

	/* Session show handler.
	 * Pseudowire-specific implementation of debugfs session rendering.
	 * The callback is called by l2tp_debugfs.c after rendering core session
	 * information.
	 */
	void (*show)(struct seq_file *m, void *priv);

	u8			priv[];		/* private data */
};

/* L2TP tunnel configuration */
struct l2tp_tunnel_cfg {
	enum l2tp_encap_type	encap;

	/* Used only for kernel-created sockets */
	struct in_addr		local_ip;
	struct in_addr		peer_ip;
#if IS_ENABLED(CONFIG_IPV6)
	struct in6_addr		*local_ip6;
	struct in6_addr		*peer_ip6;
#endif
	u16			local_udp_port;
	u16			peer_udp_port;
	unsigned int		use_udp_checksums:1,
				udp6_zero_tx_checksums:1,
				udp6_zero_rx_checksums:1;
};

/* Represents a tunnel instance.
 * Tracks runtime state including IO statistics.
 * Holds the tunnel socket (either passed from userspace or directly created by the kernel).
 * Maintains a hashlist of sessions belonging to the tunnel instance.
 * Is linked into a per-net list of tunnels.
 */
#define L2TP_TUNNEL_NAME_MAX 20
struct l2tp_tunnel {
	int			magic;		/* Should be L2TP_TUNNEL_MAGIC */

	unsigned long		dead;

	struct rcu_head rcu;
	rwlock_t		hlist_lock;	/* protect session_hlist */
	bool			acpt_newsess;	/* indicates whether this tunnel accepts
						 * new sessions. Protected by hlist_lock.
						 */
	struct hlist_head	session_hlist[L2TP_HASH_SIZE];
						/* hashed list of sessions, hashed by id */
	u32			tunnel_id;
	u32			peer_tunnel_id;
	int			version;	/* 2=>L2TPv2, 3=>L2TPv3 */

	char			name[L2TP_TUNNEL_NAME_MAX]; /* for logging */
	enum l2tp_encap_type	encap;
	struct l2tp_stats	stats;

	struct list_head	list;		/* list node on per-namespace list of tunnels */
	struct net		*l2tp_net;	/* the net we belong to */

	refcount_t		ref_count;
	void (*old_sk_destruct)(struct sock *sk);
	struct sock		*sock;		/* parent socket */
	int			fd;		/* parent fd, if tunnel socket was created
						 * by userspace
						 */

	struct work_struct	del_work;
};

/* Pseudowire ops callbacks for use with the l2tp genetlink interface */
struct l2tp_nl_cmd_ops {
	/* The pseudowire session create callback is responsible for creating a session
	 * instance for a specific pseudowire type.
	 * It must call l2tp_session_create and l2tp_session_register to register the
	 * session instance, as well as carry out any pseudowire-specific initialisation.
	 * It must return >= 0 on success, or an appropriate negative errno value on failure.
	 */
	int (*session_create)(struct net *net, struct l2tp_tunnel *tunnel,
			      u32 session_id, u32 peer_session_id,
			      struct l2tp_session_cfg *cfg);

	/* The pseudowire session delete callback is responsible for initiating the deletion
	 * of a session instance.
	 * It must call l2tp_session_delete, as well as carry out any pseudowire-specific
	 * teardown actions.
	 */
	void (*session_delete)(struct l2tp_session *session);
};

static inline void *l2tp_session_priv(struct l2tp_session *session)
{
	return &session->priv[0];
}

/* Tunnel and session refcounts */
void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel);
void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel);
void l2tp_session_inc_refcount(struct l2tp_session *session);
void l2tp_session_dec_refcount(struct l2tp_session *session);

/* Tunnel and session lookup.
 * These functions take a reference on the instances they return, so
 * the caller must ensure that the reference is dropped appropriately.
 */
struct l2tp_tunnel *l2tp_tunnel_get(const struct net *net, u32 tunnel_id);
struct l2tp_tunnel *l2tp_tunnel_get_nth(const struct net *net, int nth);
struct l2tp_session *l2tp_tunnel_get_session(struct l2tp_tunnel *tunnel,
					     u32 session_id);

struct l2tp_session *l2tp_session_get(const struct net *net, u32 session_id);
struct l2tp_session *l2tp_session_get_nth(struct l2tp_tunnel *tunnel, int nth);
struct l2tp_session *l2tp_session_get_by_ifname(const struct net *net,
						const char *ifname);

/* Tunnel and session lifetime management.
 * Creation of a new instance is a two-step process: create, then register.
 * Destruction is triggered using the *_delete functions, and completes asynchronously.
 */
int l2tp_tunnel_create(int fd, int version, u32 tunnel_id,
		       u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
		       struct l2tp_tunnel **tunnelp);
int l2tp_tunnel_register(struct l2tp_tunnel *tunnel, struct net *net,
			 struct l2tp_tunnel_cfg *cfg);
void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);

struct l2tp_session *l2tp_session_create(int priv_size,
					 struct l2tp_tunnel *tunnel,
					 u32 session_id, u32 peer_session_id,
					 struct l2tp_session_cfg *cfg);
int l2tp_session_register(struct l2tp_session *session,
			  struct l2tp_tunnel *tunnel);
void l2tp_session_delete(struct l2tp_session *session);

/* Receive path helpers.  If data sequencing is enabled for the session these
 * functions handle queuing and reordering prior to passing packets to the
 * pseudowire code to be passed to userspace.
 */
void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
		      unsigned char *ptr, unsigned char *optr, u16 hdrflags,
		      int length);
int l2tp_udp_encap_recv(struct sock *sk, struct sk_buff *skb);

/* Transmit path helpers for sending packets over the tunnel socket. */
void l2tp_session_set_header_len(struct l2tp_session *session, int version);
int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb);

/* Pseudowire management.
 * Pseudowires should register with l2tp core on module init, and unregister
 * on module exit.
 */
int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);

/* IOCTL helper for IP encap modules. */
int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);

static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
{
	switch (session->l2specific_type) {
	case L2TP_L2SPECTYPE_DEFAULT:
		return 4;
	case L2TP_L2SPECTYPE_NONE:
	default:
		return 0;
	}
}

static inline u32 l2tp_tunnel_dst_mtu(const struct l2tp_tunnel *tunnel)
{
	struct dst_entry *dst;
	u32 mtu;

	dst = sk_dst_get(tunnel->sock);
	if (!dst)
		return 0;

	mtu = dst_mtu(dst);
	dst_release(dst);

	return mtu;
}

#ifdef CONFIG_XFRM
static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel)
{
	struct sock *sk = tunnel->sock;

	return sk && (rcu_access_pointer(sk->sk_policy[0]) ||
		      rcu_access_pointer(sk->sk_policy[1]));
}
#else
static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel)
{
	return false;
}
#endif

static inline int l2tp_v3_ensure_opt_in_linear(struct l2tp_session *session, struct sk_buff *skb,
					       unsigned char **ptr, unsigned char **optr)
{
	int opt_len = session->peer_cookie_len + l2tp_get_l2specific_len(session);

	if (opt_len > 0) {
		int off = *ptr - *optr;

		if (!pskb_may_pull(skb, off + opt_len))
			return -1;

		if (skb->data != *optr) {
			*optr = skb->data;
			*ptr = skb->data + off;
		}
	}

	return 0;
}

#define MODULE_ALIAS_L2TP_PWTYPE(type) \
	MODULE_ALIAS("net-l2tp-type-" __stringify(type))

#endif /* _L2TP_CORE_H_ */
Commit	Line	Data
d2912cb1	1	/* SPDX-License-Identifier: GPL-2.0-only */
20dcb110	2	/* L2TP internal definitions.
fd558d18 JC	3	*
fd558d18 JC	4	* Copyright (c) 2008,2009 Katalix Systems Ltd
fd558d18	5	*/
fbea9e07	6	#include <linux/refcount.h>
fd558d18 JC	7
	8	#ifndef _L2TP_CORE_H_
	9	#define _L2TP_CORE_H_
	10
1f5cd2a0 GN	11	#include <net/dst.h>
	12	#include <net/sock.h>
	13
d6a61ec9 GN	14	#ifdef CONFIG_XFRM
	15	#include <net/xfrm.h>
	16	#endif
	17
340bb1ac	18	/* Random numbers used for internal consistency checks of tunnel and session structures */
fd558d18 JC	19	#define L2TP_TUNNEL_MAGIC 0x42114DDA
	20	#define L2TP_SESSION_MAGIC 0x0C04EB7D
	21
340bb1ac	22	/* Per tunnel session hash table size */
fd558d18	23	#define L2TP_HASH_BITS 4
dbf82f3f	24	#define L2TP_HASH_SIZE BIT(L2TP_HASH_BITS)
fd558d18	25
340bb1ac	26	/* System-wide session hash table size */
f7faffa3	27	#define L2TP_HASH_BITS_2 8
dbf82f3f	28	#define L2TP_HASH_SIZE_2 BIT(L2TP_HASH_BITS_2)
f7faffa3	29
fd558d18 JC	30	struct sk_buff;
	31
	32	struct l2tp_stats {
7b7c0719 TP	33	atomic_long_t tx_packets;
	34	atomic_long_t tx_bytes;
	35	atomic_long_t tx_errors;
	36	atomic_long_t rx_packets;
	37	atomic_long_t rx_bytes;
	38	atomic_long_t rx_seq_discards;
	39	atomic_long_t rx_oos_packets;
	40	atomic_long_t rx_errors;
	41	atomic_long_t rx_cookie_discards;
fd558d18 JC	42	};
	43
	44	struct l2tp_tunnel;
	45
340bb1ac	46	/* L2TP session configuration */
fd558d18	47	struct l2tp_session_cfg {
f7faffa3	48	enum l2tp_pwtype pw_type;
20dcb110 TP	49	unsigned int recv_seq:1; /* expect receive packets with sequence numbers? */
	50	unsigned int send_seq:1; /* send packets with sequence numbers? */
	51	unsigned int lns_mode:1; /* behave as LNS?
	52	* LAC enables sequence numbers under LNS control.
	53	*/
f7faffa3 JC	54	u16 l2specific_type; /* Layer 2 specific type */
	55	u8 cookie[8]; /* optional cookie */
	56	int cookie_len; /* 0, 4 or 8 bytes */
	57	u8 peer_cookie[8]; /* peer's cookie */
	58	int peer_cookie_len; /* 0, 4 or 8 bytes */
20dcb110	59	int reorder_timeout; /* configured reorder timeout (in jiffies) */
309795f4	60	char *ifname;
fd558d18 JC	61	};
fd558d18 JC	62
340bb1ac TP	63	/* Represents a session (pseudowire) instance.
	64	* Tracks runtime state including cookies, dataplane packet sequencing, and IO statistics.
	65	* Is linked into a per-tunnel session hashlist; and in the case of an L2TPv3 session into
	66	* an additional per-net ("global") hashlist.
	67	*/
2a03dd8e	68	#define L2TP_SESSION_NAME_MAX 32
fd558d18	69	struct l2tp_session {
20dcb110	70	int magic; /* should be L2TP_SESSION_MAGIC */
b228a940	71	long dead;
fd558d18	72
20dcb110	73	struct l2tp_tunnel tunnel; / back pointer to tunnel context */
fd558d18 JC	74	u32 session_id;
fd558d18 JC	75	u32 peer_session_id;
f7faffa3 JC	76	u8 cookie[8];
	77	int cookie_len;
	78	u8 peer_cookie[8];
	79	int peer_cookie_len;
f7faffa3 JC	80	u16 l2specific_type;
	81	u16 hdr_len;
	82	u32 nr; /* session NR state (receive) */
	83	u32 ns; /* session NR state (send) */
fd558d18	84	struct sk_buff_head reorder_q; /* receive reorder queue */
8a1631d5 JC	85	u32 nr_max; /* max NR. Depends on tunnel */
8a1631d5 JC	86	u32 nr_window_size; /* NR window size */
a0dbd822	87	u32 nr_oos; /* NR of last OOS packet */
20dcb110	88	int nr_oos_count; /* for OOS recovery */
a0dbd822	89	int nr_oos_count_max;
20dcb110	90	struct hlist_node hlist; /* hash list node */
f00c854c	91	refcount_t ref_count;
fd558d18	92
2a03dd8e	93	char name[L2TP_SESSION_NAME_MAX]; /* for logging */
309795f4	94	char ifname[IFNAMSIZ];
20dcb110 TP	95	unsigned int recv_seq:1; /* expect receive packets with sequence numbers? */
	96	unsigned int send_seq:1; /* send packets with sequence numbers? */
	97	unsigned int lns_mode:1; /* behave as LNS?
	98	* LAC enables sequence numbers under LNS control.
	99	*/
20dcb110	100	int reorder_timeout; /* configured reorder timeout (in jiffies) */
38d40b3f	101	int reorder_skip; /* set if skip to next nr */
f7faffa3	102	enum l2tp_pwtype pwtype;
fd558d18	103	struct l2tp_stats stats;
20dcb110	104	struct hlist_node global_hlist; /* global hash list node */
fd558d18	105
340bb1ac TP	106	/* Session receive handler for data packets.
	107	* Each pseudowire implementation should implement this callback in order to
	108	* handle incoming packets. Packets are passed to the pseudowire handler after
	109	* reordering, if data sequence numbers are enabled for the session.
	110	*/
fd558d18	111	void (recv_skb)(struct l2tp_session session, struct sk_buff *skb, int data_len);
340bb1ac TP	112
	113	/* Session close handler.
	114	* Each pseudowire implementation may implement this callback in order to carry
	115	* out pseudowire-specific shutdown actions.
	116	* The callback is called by core after unhashing the session and purging its
	117	* reorder queue.
	118	*/
fd558d18	119	void (session_close)(struct l2tp_session session);
340bb1ac TP	120
	121	/* Session show handler.
	122	* Pseudowire-specific implementation of debugfs session rendering.
	123	* The callback is called by l2tp_debugfs.c after rendering core session
	124	* information.
	125	*/
0ad66140	126	void (show)(struct seq_file m, void *priv);
340bb1ac	127
20dcb110	128	u8 priv[]; /* private data */
fd558d18 JC	129	};
fd558d18 JC	130
340bb1ac	131	/* L2TP tunnel configuration */
fd558d18	132	struct l2tp_tunnel_cfg {
0d76751f	133	enum l2tp_encap_type encap;
789a4a2c JC	134
	135	/* Used only for kernel-created sockets */
	136	struct in_addr local_ip;
	137	struct in_addr peer_ip;
f9bac8df CE	138	#if IS_ENABLED(CONFIG_IPV6)
	139	struct in6_addr *local_ip6;
	140	struct in6_addr *peer_ip6;
	141	#endif
789a4a2c JC	142	u16 local_udp_port;
789a4a2c JC	143	u16 peer_udp_port;
6b649fea TH	144	unsigned int use_udp_checksums:1,
	145	udp6_zero_tx_checksums:1,
	146	udp6_zero_rx_checksums:1;
fd558d18 JC	147	};
fd558d18 JC	148
340bb1ac TP	149	/* Represents a tunnel instance.
	150	* Tracks runtime state including IO statistics.
	151	* Holds the tunnel socket (either passed from userspace or directly created by the kernel).
	152	* Maintains a hashlist of sessions belonging to the tunnel instance.
	153	* Is linked into a per-net list of tunnels.
	154	*/
2a03dd8e	155	#define L2TP_TUNNEL_NAME_MAX 20
fd558d18 JC	156	struct l2tp_tunnel {
fd558d18 JC	157	int magic; /* Should be L2TP_TUNNEL_MAGIC */
62b982ee SD	158
	159	unsigned long dead;
	160
99469c32	161	struct rcu_head rcu;
fd558d18	162	rwlock_t hlist_lock; /* protect session_hlist */
20dcb110 TP	163	bool acpt_newsess; /* indicates whether this tunnel accepts
20dcb110 TP	164	* new sessions. Protected by hlist_lock.
f3c66d4e	165	*/
fd558d18	166	struct hlist_head session_hlist[L2TP_HASH_SIZE];
20dcb110	167	/* hashed list of sessions, hashed by id */
fd558d18 JC	168	u32 tunnel_id;
	169	u32 peer_tunnel_id;
	170	int version; /* 2=>L2TPv2, 3=>L2TPv3 */
	171
2a03dd8e	172	char name[L2TP_TUNNEL_NAME_MAX]; /* for logging */
0d76751f	173	enum l2tp_encap_type encap;
fd558d18 JC	174	struct l2tp_stats stats;
fd558d18 JC	175
20dcb110	176	struct list_head list; /* list node on per-namespace list of tunnels */
fd558d18 JC	177	struct net l2tp_net; / the net we belong to */
fd558d18 JC	178
fbea9e07	179	refcount_t ref_count;
bef04d16	180	void (old_sk_destruct)(struct sock sk);
20dcb110 TP	181	struct sock sock; / parent socket */
	182	int fd; /* parent fd, if tunnel socket was created
	183	* by userspace
	184	*/
fd558d18	185
f8ccac0e	186	struct work_struct del_work;
fd558d18 JC	187	};
fd558d18 JC	188
340bb1ac	189	/* Pseudowire ops callbacks for use with the l2tp genetlink interface */
309795f4	190	struct l2tp_nl_cmd_ops {
340bb1ac TP	191	/* The pseudowire session create callback is responsible for creating a session
	192	* instance for a specific pseudowire type.
	193	* It must call l2tp_session_create and l2tp_session_register to register the
	194	* session instance, as well as carry out any pseudowire-specific initialisation.
	195	* It must return >= 0 on success, or an appropriate negative errno value on failure.
	196	*/
f026bc29 GN	197	int (session_create)(struct net net, struct l2tp_tunnel *tunnel,
	198	u32 session_id, u32 peer_session_id,
	199	struct l2tp_session_cfg *cfg);
340bb1ac TP	200
	201	/* The pseudowire session delete callback is responsible for initiating the deletion
	202	* of a session instance.
	203	* It must call l2tp_session_delete, as well as carry out any pseudowire-specific
	204	* teardown actions.
	205	*/
628703f5	206	void (session_delete)(struct l2tp_session session);
309795f4 JC	207	};
309795f4 JC	208
fd558d18 JC	209	static inline void l2tp_session_priv(struct l2tp_session session)
	210	{
	211	return &session->priv[0];
	212	}
	213
340bb1ac	214	/* Tunnel and session refcounts */
52016e25 TP	215	void l2tp_tunnel_inc_refcount(struct l2tp_tunnel *tunnel);
	216	void l2tp_tunnel_dec_refcount(struct l2tp_tunnel *tunnel);
	217	void l2tp_session_inc_refcount(struct l2tp_session *session);
	218	void l2tp_session_dec_refcount(struct l2tp_session *session);
	219
340bb1ac TP	220	/* Tunnel and session lookup.
	221	* These functions take a reference on the instances they return, so
	222	* the caller must ensure that the reference is dropped appropriately.
	223	*/
54652eb1	224	struct l2tp_tunnel l2tp_tunnel_get(const struct net net, u32 tunnel_id);
5846c131	225	struct l2tp_tunnel l2tp_tunnel_get_nth(const struct net net, int nth);
01e28b92 GN	226	struct l2tp_session l2tp_tunnel_get_session(struct l2tp_tunnel tunnel,
01e28b92 GN	227	u32 session_id);
5846c131	228
01e28b92	229	struct l2tp_session l2tp_session_get(const struct net net, u32 session_id);
a4346210	230	struct l2tp_session l2tp_session_get_nth(struct l2tp_tunnel tunnel, int nth);
9aaef50c	231	struct l2tp_session l2tp_session_get_by_ifname(const struct net net,
a4346210	232	const char *ifname);
c1b1203d	233
340bb1ac TP	234	/* Tunnel and session lifetime management.
	235	* Creation of a new instance is a two-step process: create, then register.
	236	* Destruction is triggered using the *_delete functions, and completes asynchronously.
	237	*/
c9ccd4c6	238	int l2tp_tunnel_create(int fd, int version, u32 tunnel_id,
c1b1203d JP	239	u32 peer_tunnel_id, struct l2tp_tunnel_cfg *cfg,
c1b1203d JP	240	struct l2tp_tunnel **tunnelp);
6b9f3423 GN	241	int l2tp_tunnel_register(struct l2tp_tunnel tunnel, struct net net,
6b9f3423 GN	242	struct l2tp_tunnel_cfg *cfg);
62b982ee	243	void l2tp_tunnel_delete(struct l2tp_tunnel *tunnel);
340bb1ac	244
c1b1203d JP	245	struct l2tp_session *l2tp_session_create(int priv_size,
	246	struct l2tp_tunnel *tunnel,
	247	u32 session_id, u32 peer_session_id,
	248	struct l2tp_session_cfg *cfg);
3953ae7b GN	249	int l2tp_session_register(struct l2tp_session *session,
3953ae7b GN	250	struct l2tp_tunnel *tunnel);
628703f5	251	void l2tp_session_delete(struct l2tp_session *session);
340bb1ac TP	252
	253	/* Receive path helpers. If data sequencing is enabled for the session these
	254	* functions handle queuing and reordering prior to passing packets to the
	255	* pseudowire code to be passed to userspace.
	256	*/
c1b1203d JP	257	void l2tp_recv_common(struct l2tp_session session, struct sk_buff skb,
c1b1203d JP	258	unsigned char ptr, unsigned char optr, u16 hdrflags,
2b139e6b	259	int length);
c1b1203d JP	260	int l2tp_udp_encap_recv(struct sock sk, struct sk_buff skb);
c1b1203d JP	261
340bb1ac TP	262	/* Transmit path helpers for sending packets over the tunnel socket. */
340bb1ac TP	263	void l2tp_session_set_header_len(struct l2tp_session *session, int version);
efe05278	264	int l2tp_xmit_skb(struct l2tp_session session, struct sk_buff skb);
c1b1203d	265
340bb1ac TP	266	/* Pseudowire management.
	267	* Pseudowires should register with l2tp core on module init, and unregister
	268	* on module exit.
	269	*/
	270	int l2tp_nl_register_ops(enum l2tp_pwtype pw_type, const struct l2tp_nl_cmd_ops *ops);
c1b1203d	271	void l2tp_nl_unregister_ops(enum l2tp_pwtype pw_type);
340bb1ac TP	272
340bb1ac TP	273	/* IOCTL helper for IP encap modules. */
72fb96e7	274	int l2tp_ioctl(struct sock *sk, int cmd, unsigned long arg);
309795f4	275
62e7b6a5 LB	276	static inline int l2tp_get_l2specific_len(struct l2tp_session *session)
	277	{
	278	switch (session->l2specific_type) {
	279	case L2TP_L2SPECTYPE_DEFAULT:
	280	return 4;
	281	case L2TP_L2SPECTYPE_NONE:
	282	default:
	283	return 0;
	284	}
	285	}
	286
1f5cd2a0 GN	287	static inline u32 l2tp_tunnel_dst_mtu(const struct l2tp_tunnel *tunnel)
	288	{
	289	struct dst_entry *dst;
	290	u32 mtu;
	291
	292	dst = sk_dst_get(tunnel->sock);
	293	if (!dst)
	294	return 0;
	295
	296	mtu = dst_mtu(dst);
	297	dst_release(dst);
	298
	299	return mtu;
	300	}
	301
d6a61ec9 GN	302	#ifdef CONFIG_XFRM
	303	static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel)
	304	{
	305	struct sock *sk = tunnel->sock;
	306
	307	return sk && (rcu_access_pointer(sk->sk_policy[0]) \|\|
	308	rcu_access_pointer(sk->sk_policy[1]));
	309	}
	310	#else
	311	static inline bool l2tp_tunnel_uses_xfrm(const struct l2tp_tunnel *tunnel)
	312	{
	313	return false;
	314	}
	315	#endif
	316
4522a70d JW	317	static inline int l2tp_v3_ensure_opt_in_linear(struct l2tp_session session, struct sk_buff skb,
	318	unsigned char ptr, unsigned char optr)
	319	{
	320	int opt_len = session->peer_cookie_len + l2tp_get_l2specific_len(session);
	321
	322	if (opt_len > 0) {
	323	int off = ptr - optr;
	324
	325	if (!pskb_may_pull(skb, off + opt_len))
	326	return -1;
	327
	328	if (skb->data != *optr) {
	329	*optr = skb->data;
	330	*ptr = skb->data + off;
	331	}
	332	}
	333
	334	return 0;
	335	}
	336
f1f39f91	337	#define MODULE_ALIAS_L2TP_PWTYPE(type) \
	338	MODULE_ALIAS("net-l2tp-type-" __stringify(type))
	339
fd558d18	340	#endif /* _L2TP_CORE_H_ */