linux/include/net/xfrm.h

#ifndef _NET_XFRM_H
#define _NET_XFRM_H

#include <linux/compiler.h>
#include <linux/xfrm.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/pfkeyv2.h>
#include <linux/ipsec.h>
#include <linux/in6.h>
#include <linux/mutex.h>
#include <linux/audit.h>
#include <linux/slab.h>

#include <net/sock.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/ipv6.h>
#include <net/ip6_fib.h>
#include <net/flow.h>

#include <linux/interrupt.h>

#ifdef CONFIG_XFRM_STATISTICS
#include <net/snmp.h>
#endif

#define XFRM_PROTO_ESP		50
#define XFRM_PROTO_AH		51
#define XFRM_PROTO_COMP		108
#define XFRM_PROTO_IPIP		4
#define XFRM_PROTO_IPV6		41
#define XFRM_PROTO_ROUTING	IPPROTO_ROUTING
#define XFRM_PROTO_DSTOPTS	IPPROTO_DSTOPTS

#define XFRM_ALIGN4(len)	(((len) + 3) & ~3)
#define XFRM_ALIGN8(len)	(((len) + 7) & ~7)
#define MODULE_ALIAS_XFRM_MODE(family, encap) \
	MODULE_ALIAS("xfrm-mode-" __stringify(family) "-" __stringify(encap))
#define MODULE_ALIAS_XFRM_TYPE(family, proto) \
	MODULE_ALIAS("xfrm-type-" __stringify(family) "-" __stringify(proto))

#ifdef CONFIG_XFRM_STATISTICS
#define XFRM_INC_STATS(net, field)	SNMP_INC_STATS((net)->mib.xfrm_statistics, field)
#define XFRM_INC_STATS_BH(net, field)	SNMP_INC_STATS_BH((net)->mib.xfrm_statistics, field)
#define XFRM_INC_STATS_USER(net, field)	SNMP_INC_STATS_USER((net)-mib.xfrm_statistics, field)
#else
#define XFRM_INC_STATS(net, field)	((void)(net))
#define XFRM_INC_STATS_BH(net, field)	((void)(net))
#define XFRM_INC_STATS_USER(net, field)	((void)(net))
#endif

extern struct mutex xfrm_cfg_mutex;

/* Organization of SPD aka "XFRM rules"
   ------------------------------------

   Basic objects:
   - policy rule, struct xfrm_policy (=SPD entry)
   - bundle of transformations, struct dst_entry == struct xfrm_dst (=SA bundle)
   - instance of a transformer, struct xfrm_state (=SA)
   - template to clone xfrm_state, struct xfrm_tmpl

   SPD is plain linear list of xfrm_policy rules, ordered by priority.
   (To be compatible with existing pfkeyv2 implementations,
   many rules with priority of 0x7fffffff are allowed to exist and
   such rules are ordered in an unpredictable way, thanks to bsd folks.)

   Lookup is plain linear search until the first match with selector.

   If "action" is "block", then we prohibit the flow, otherwise:
   if "xfrms_nr" is zero, the flow passes untransformed. Otherwise,
   policy entry has list of up to XFRM_MAX_DEPTH transformations,
   described by templates xfrm_tmpl. Each template is resolved
   to a complete xfrm_state (see below) and we pack bundle of transformations
   to a dst_entry returned to requestor.

   dst -. xfrm  .-> xfrm_state #1
    |---. child .-> dst -. xfrm .-> xfrm_state #2
                     |---. child .-> dst -. xfrm .-> xfrm_state #3
                                      |---. child .-> NULL

   Bundles are cached at xrfm_policy struct (field ->bundles).


   Resolution of xrfm_tmpl
   -----------------------
   Template contains:
   1. ->mode		Mode: transport or tunnel
   2. ->id.proto	Protocol: AH/ESP/IPCOMP
   3. ->id.daddr	Remote tunnel endpoint, ignored for transport mode.
      Q: allow to resolve security gateway?
   4. ->id.spi          If not zero, static SPI.
   5. ->saddr		Local tunnel endpoint, ignored for transport mode.
   6. ->algos		List of allowed algos. Plain bitmask now.
      Q: ealgos, aalgos, calgos. What a mess...
   7. ->share		Sharing mode.
      Q: how to implement private sharing mode? To add struct sock* to
      flow id?

   Having this template we search through SAD searching for entries
   with appropriate mode/proto/algo, permitted by selector.
   If no appropriate entry found, it is requested from key manager.

   PROBLEMS:
   Q: How to find all the bundles referring to a physical path for
      PMTU discovery? Seems, dst should contain list of all parents...
      and enter to infinite locking hierarchy disaster.
      No! It is easier, we will not search for them, let them find us.
      We add genid to each dst plus pointer to genid of raw IP route,
      pmtu disc will update pmtu on raw IP route and increase its genid.
      dst_check() will see this for top level and trigger resyncing
      metrics. Plus, it will be made via sk->sk_dst_cache. Solved.
 */

struct xfrm_state_walk {
	struct list_head	all;
	u8			state;
	union {
		u8		dying;
		u8		proto;
	};
	u32			seq;
};

/* Full description of state of transformer. */
struct xfrm_state {
#ifdef CONFIG_NET_NS
	struct net		*xs_net;
#endif
	union {
		struct hlist_node	gclist;
		struct hlist_node	bydst;
	};
	struct hlist_node	bysrc;
	struct hlist_node	byspi;

	atomic_t		refcnt;
	spinlock_t		lock;

	struct xfrm_id		id;
	struct xfrm_selector	sel;
	struct xfrm_mark	mark;
	u32			tfcpad;

	u32			genid;

	/* Key manager bits */
	struct xfrm_state_walk	km;

	/* Parameters of this state. */
	struct {
		u32		reqid;
		u8		mode;
		u8		replay_window;
		u8		aalgo, ealgo, calgo;
		u8		flags;
		u16		family;
		xfrm_address_t	saddr;
		int		header_len;
		int		trailer_len;
	} props;

	struct xfrm_lifetime_cfg lft;

	/* Data for transformer */
	struct xfrm_algo_auth	*aalg;
	struct xfrm_algo	*ealg;
	struct xfrm_algo	*calg;
	struct xfrm_algo_aead	*aead;

	/* Data for encapsulator */
	struct xfrm_encap_tmpl	*encap;

	/* Data for care-of address */
	xfrm_address_t	*coaddr;

	/* IPComp needs an IPIP tunnel for handling uncompressed packets */
	struct xfrm_state	*tunnel;

	/* If a tunnel, number of users + 1 */
	atomic_t		tunnel_users;

	/* State for replay detection */
	struct xfrm_replay_state replay;
	struct xfrm_replay_state_esn *replay_esn;

	/* Replay detection state at the time we sent the last notification */
	struct xfrm_replay_state preplay;
	struct xfrm_replay_state_esn *preplay_esn;

	/* internal flag that only holds state for delayed aevent at the
	 * moment
	*/
	u32			xflags;

	/* Replay detection notification settings */
	u32			replay_maxage;
	u32			replay_maxdiff;

	/* Replay detection notification timer */
	struct timer_list	rtimer;

	/* Statistics */
	struct xfrm_stats	stats;

	struct xfrm_lifetime_cur curlft;
	struct tasklet_hrtimer	mtimer;

	/* Last used time */
	unsigned long		lastused;

	/* Reference to data common to all the instances of this
	 * transformer. */
	const struct xfrm_type	*type;
	struct xfrm_mode	*inner_mode;
	struct xfrm_mode	*inner_mode_iaf;
	struct xfrm_mode	*outer_mode;

	/* Security context */
	struct xfrm_sec_ctx	*security;

	/* Private data of this transformer, format is opaque,
	 * interpreted by xfrm_type methods. */
	void			*data;
};

static inline struct net *xs_net(struct xfrm_state *x)
{
	return read_pnet(&x->xs_net);
}

/* xflags - make enum if more show up */
#define XFRM_TIME_DEFER	1

enum {
	XFRM_STATE_VOID,
	XFRM_STATE_ACQ,
	XFRM_STATE_VALID,
	XFRM_STATE_ERROR,
	XFRM_STATE_EXPIRED,
	XFRM_STATE_DEAD
};

/* callback structure passed from either netlink or pfkey */
struct km_event {
	union {
		u32 hard;
		u32 proto;
		u32 byid;
		u32 aevent;
		u32 type;
	} data;

	u32	seq;
	u32	pid;
	u32	event;
	struct net *net;
};

struct net_device;
struct xfrm_type;
struct xfrm_dst;
struct xfrm_policy_afinfo {
	unsigned short		family;
	struct dst_ops		*dst_ops;
	void			(*garbage_collect)(struct net *net);
	struct dst_entry	*(*dst_lookup)(struct net *net, int tos,
					       const xfrm_address_t *saddr,
					       const xfrm_address_t *daddr);
	int			(*get_saddr)(struct net *net, xfrm_address_t *saddr, xfrm_address_t *daddr);
	void			(*decode_session)(struct sk_buff *skb,
						  struct flowi *fl,
						  int reverse);
	int			(*get_tos)(const struct flowi *fl);
	int			(*init_path)(struct xfrm_dst *path,
					     struct dst_entry *dst,
					     int nfheader_len);
	int			(*fill_dst)(struct xfrm_dst *xdst,
					    struct net_device *dev,
					    const struct flowi *fl);
	struct dst_entry	*(*blackhole_route)(struct net *net, struct dst_entry *orig);
};

extern int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo);
extern int xfrm_policy_unregister_afinfo(struct xfrm_policy_afinfo *afinfo);
extern void km_policy_notify(struct xfrm_policy *xp, int dir, const struct km_event *c);
extern void km_state_notify(struct xfrm_state *x, const struct km_event *c);

struct xfrm_tmpl;
extern int km_query(struct xfrm_state *x, struct xfrm_tmpl *t, struct xfrm_policy *pol);
extern void km_state_expired(struct xfrm_state *x, int hard, u32 pid);
extern int __xfrm_state_delete(struct xfrm_state *x);

struct xfrm_state_afinfo {
	unsigned int		family;
	unsigned int		proto;
	__be16			eth_proto;
	struct module		*owner;
	const struct xfrm_type	*type_map[IPPROTO_MAX];
	struct xfrm_mode	*mode_map[XFRM_MODE_MAX];
	int			(*init_flags)(struct xfrm_state *x);
	void			(*init_tempsel)(struct xfrm_selector *sel,
						const struct flowi *fl);
	void			(*init_temprop)(struct xfrm_state *x,
						const struct xfrm_tmpl *tmpl,
						const xfrm_address_t *daddr,
						const xfrm_address_t *saddr);
	int			(*tmpl_sort)(struct xfrm_tmpl **dst, struct xfrm_tmpl **src, int n);
	int			(*state_sort)(struct xfrm_state **dst, struct xfrm_state **src, int n);
	int			(*output)(struct sk_buff *skb);
	int			(*extract_input)(struct xfrm_state *x,
						 struct sk_buff *skb);
	int			(*extract_output)(struct xfrm_state *x,
						  struct sk_buff *skb);
	int			(*transport_finish)(struct sk_buff *skb,
						    int async);
};

extern int xfrm_state_register_afinfo(struct xfrm_state_afinfo *afinfo);
extern int xfrm_state_unregister_afinfo(struct xfrm_state_afinfo *afinfo);

extern void xfrm_state_delete_tunnel(struct xfrm_state *x);

struct xfrm_type {
	char			*description;
	struct module		*owner;
	u8			proto;
	u8			flags;
#define XFRM_TYPE_NON_FRAGMENT	1
#define XFRM_TYPE_REPLAY_PROT	2
#define XFRM_TYPE_LOCAL_COADDR	4
#define XFRM_TYPE_REMOTE_COADDR	8

	int			(*init_state)(struct xfrm_state *x);
	void			(*destructor)(struct xfrm_state *);
	int			(*input)(struct xfrm_state *, struct sk_buff *skb);
	int			(*output)(struct xfrm_state *, struct sk_buff *pskb);
	int			(*reject)(struct xfrm_state *, struct sk_buff *,
					  const struct flowi *);
	int			(*hdr_offset)(struct xfrm_state *, struct sk_buff *, u8 **);
	/* Estimate maximal size of result of transformation of a dgram */
	u32			(*get_mtu)(struct xfrm_state *, int size);
};

extern int xfrm_register_type(const struct xfrm_type *type, unsigned short family);
extern int xfrm_unregister_type(const struct xfrm_type *type, unsigned short family);

struct xfrm_mode {
	/*
	 * Remove encapsulation header.
	 *
	 * The IP header will be moved over the top of the encapsulation
	 * header.
	 *
	 * On entry, the transport header shall point to where the IP header
	 * should be and the network header shall be set to where the IP
	 * header currently is.  skb->data shall point to the start of the
	 * payload.
	 */
	int (*input2)(struct xfrm_state *x, struct sk_buff *skb);

	/*
	 * This is the actual input entry point.
	 *
	 * For transport mode and equivalent this would be identical to
	 * input2 (which does not need to be set).  While tunnel mode
	 * and equivalent would set this to the tunnel encapsulation function
	 * xfrm4_prepare_input that would in turn call input2.
	 */
	int (*input)(struct xfrm_state *x, struct sk_buff *skb);

	/*
	 * Add encapsulation header.
	 *
	 * On exit, the transport header will be set to the start of the
	 * encapsulation header to be filled in by x->type->output and
	 * the mac header will be set to the nextheader (protocol for
	 * IPv4) field of the extension header directly preceding the
	 * encapsulation header, or in its absence, that of the top IP
	 * header.  The value of the network header will always point
	 * to the top IP header while skb->data will point to the payload.
	 */
	int (*output2)(struct xfrm_state *x,struct sk_buff *skb);

	/*
	 * This is the actual output entry point.
	 *
	 * For transport mode and equivalent this would be identical to
	 * output2 (which does not need to be set).  While tunnel mode
	 * and equivalent would set this to a tunnel encapsulation function
	 * (xfrm4_prepare_output or xfrm6_prepare_output) that would in turn
	 * call output2.
	 */
	int (*output)(struct xfrm_state *x, struct sk_buff *skb);

	struct xfrm_state_afinfo *afinfo;
	struct module *owner;
	unsigned int encap;
	int flags;
};

/* Flags for xfrm_mode. */
enum {
	XFRM_MODE_FLAG_TUNNEL = 1,
};

extern int xfrm_register_mode(struct xfrm_mode *mode, int family);
extern int xfrm_unregister_mode(struct xfrm_mode *mode, int family);

static inline int xfrm_af2proto(unsigned int family)
{
	switch(family) {
	case AF_INET:
		return IPPROTO_IPIP;
	case AF_INET6:
		return IPPROTO_IPV6;
	default:
		return 0;
	}
}

static inline struct xfrm_mode *xfrm_ip2inner_mode(struct xfrm_state *x, int ipproto)
{
	if ((ipproto == IPPROTO_IPIP && x->props.family == AF_INET) ||
	    (ipproto == IPPROTO_IPV6 && x->props.family == AF_INET6))
		return x->inner_mode;
	else
		return x->inner_mode_iaf;
}

struct xfrm_tmpl {
/* id in template is interpreted as:
 * daddr - destination of tunnel, may be zero for transport mode.
 * spi   - zero to acquire spi. Not zero if spi is static, then
 *	   daddr must be fixed too.
 * proto - AH/ESP/IPCOMP
 */
	struct xfrm_id		id;

/* Source address of tunnel. Ignored, if it is not a tunnel. */
	xfrm_address_t		saddr;

	unsigned short		encap_family;

	u32			reqid;

/* Mode: transport, tunnel etc. */
	u8			mode;

/* Sharing mode: unique, this session only, this user only etc. */
	u8			share;

/* May skip this transfomration if no SA is found */
	u8			optional;

/* Skip aalgos/ealgos/calgos checks. */
	u8			allalgs;

/* Bit mask of algos allowed for acquisition */
	u32			aalgos;
	u32			ealgos;
	u32			calgos;
};

#define XFRM_MAX_DEPTH		6

struct xfrm_policy_walk_entry {
	struct list_head	all;
	u8			dead;
};

struct xfrm_policy_walk {
	struct xfrm_policy_walk_entry walk;
	u8 type;
	u32 seq;
};

struct xfrm_policy {
#ifdef CONFIG_NET_NS
	struct net		*xp_net;
#endif
	struct hlist_node	bydst;
	struct hlist_node	byidx;

	/* This lock only affects elements except for entry. */
	rwlock_t		lock;
	atomic_t		refcnt;
	struct timer_list	timer;

	struct flow_cache_object flo;
	atomic_t		genid;
	u32			priority;
	u32			index;
	struct xfrm_mark	mark;
	struct xfrm_selector	selector;
	struct xfrm_lifetime_cfg lft;
	struct xfrm_lifetime_cur curlft;
	struct xfrm_policy_walk_entry walk;
	u8			type;
	u8			action;
	u8			flags;
	u8			xfrm_nr;
	u16			family;
	struct xfrm_sec_ctx	*security;
	struct xfrm_tmpl       	xfrm_vec[XFRM_MAX_DEPTH];
};

static inline struct net *xp_net(const struct xfrm_policy *xp)
{
	return read_pnet(&xp->xp_net);
}

struct xfrm_kmaddress {
	xfrm_address_t          local;
	xfrm_address_t          remote;
	u32			reserved;
	u16			family;
};

struct xfrm_migrate {
	xfrm_address_t		old_daddr;
	xfrm_address_t		old_saddr;
	xfrm_address_t		new_daddr;
	xfrm_address_t		new_saddr;
	u8			proto;
	u8			mode;
	u16			reserved;
	u32			reqid;
	u16			old_family;
	u16			new_family;
};

#define XFRM_KM_TIMEOUT                30
/* which seqno */
#define XFRM_REPLAY_SEQ		1
#define XFRM_REPLAY_OSEQ	2
#define XFRM_REPLAY_SEQ_MASK	3
/* what happened */
#define XFRM_REPLAY_UPDATE	XFRM_AE_CR
#define XFRM_REPLAY_TIMEOUT	XFRM_AE_CE

/* default aevent timeout in units of 100ms */
#define XFRM_AE_ETIME			10
/* Async Event timer multiplier */
#define XFRM_AE_ETH_M			10
/* default seq threshold size */
#define XFRM_AE_SEQT_SIZE		2

struct xfrm_mgr {
	struct list_head	list;
	char			*id;
	int			(*notify)(struct xfrm_state *x, const struct km_event *c);
	int			(*acquire)(struct xfrm_state *x, struct xfrm_tmpl *, struct xfrm_policy *xp, int dir);
	struct xfrm_policy	*(*compile_policy)(struct sock *sk, int opt, u8 *data, int len, int *dir);
	int			(*new_mapping)(struct xfrm_state *x, xfrm_address_t *ipaddr, __be16 sport);
	int			(*notify_policy)(struct xfrm_policy *x, int dir, const struct km_event *c);
	int			(*report)(struct net *net, u8 proto, struct xfrm_selector *sel, xfrm_address_t *addr);
	int			(*migrate)(const struct xfrm_selector *sel,
					   u8 dir, u8 type,
					   const struct xfrm_migrate *m,
					   int num_bundles,
					   const struct xfrm_kmaddress *k);
};

extern int xfrm_register_km(struct xfrm_mgr *km);
extern int xfrm_unregister_km(struct xfrm_mgr *km);

/*
 * This structure is used for the duration where packets are being
 * transformed by IPsec.  As soon as the packet leaves IPsec the
 * area beyond the generic IP part may be overwritten.
 */
struct xfrm_skb_cb {
	union {
		struct inet_skb_parm h4;
		struct inet6_skb_parm h6;
        } header;

        /* Sequence number for replay protection. */
	union {
		struct {
			__u32 low;
			__u32 hi;
		} output;
		struct {
			__be32 low;
			__be32 hi;
		} input;
	} seq;
};

#define XFRM_SKB_CB(__skb) ((struct xfrm_skb_cb *)&((__skb)->cb[0]))

/*
 * This structure is used by the afinfo prepare_input/prepare_output functions
 * to transmit header information to the mode input/output functions.
 */
struct xfrm_mode_skb_cb {
	union {
		struct inet_skb_parm h4;
		struct inet6_skb_parm h6;
	} header;

	/* Copied from header for IPv4, always set to zero and DF for IPv6. */
	__be16 id;
	__be16 frag_off;

	/* IP header length (excluding options or extension headers). */
	u8 ihl;

	/* TOS for IPv4, class for IPv6. */
	u8 tos;

	/* TTL for IPv4, hop limitfor IPv6. */
	u8 ttl;

	/* Protocol for IPv4, NH for IPv6. */
	u8 protocol;

	/* Option length for IPv4, zero for IPv6. */
	u8 optlen;

	/* Used by IPv6 only, zero for IPv4. */
	u8 flow_lbl[3];
};

#define XFRM_MODE_SKB_CB(__skb) ((struct xfrm_mode_skb_cb *)&((__skb)->cb[0]))

/*
 * This structure is used by the input processing to locate the SPI and
 * related information.
 */
struct xfrm_spi_skb_cb {
	union {
		struct inet_skb_parm h4;
		struct inet6_skb_parm h6;
	} header;

	unsigned int daddroff;
	unsigned int family;
};

#define XFRM_SPI_SKB_CB(__skb) ((struct xfrm_spi_skb_cb *)&((__skb)->cb[0]))

/* Audit Information */
struct xfrm_audit {
	u32	secid;
	uid_t	loginuid;
	u32	sessionid;
};

#ifdef CONFIG_AUDITSYSCALL
static inline struct audit_buffer *xfrm_audit_start(const char *op)
{
	struct audit_buffer *audit_buf = NULL;

	if (audit_enabled == 0)
		return NULL;
	audit_buf = audit_log_start(current->audit_context, GFP_ATOMIC,
				    AUDIT_MAC_IPSEC_EVENT);
	if (audit_buf == NULL)
		return NULL;
	audit_log_format(audit_buf, "op=%s", op);
	return audit_buf;
}

static inline void xfrm_audit_helper_usrinfo(uid_t auid, u32 ses, u32 secid,
					     struct audit_buffer *audit_buf)
{
	char *secctx;
	u32 secctx_len;

	audit_log_format(audit_buf, " auid=%u ses=%u", auid, ses);
	if (secid != 0 &&
	    security_secid_to_secctx(secid, &secctx, &secctx_len) == 0) {
		audit_log_format(audit_buf, " subj=%s", secctx);
		security_release_secctx(secctx, secctx_len);
	} else
		audit_log_task_context(audit_buf);
}

extern void xfrm_audit_policy_add(struct xfrm_policy *xp, int result,
				  u32 auid, u32 ses, u32 secid);
extern void xfrm_audit_policy_delete(struct xfrm_policy *xp, int result,
				  u32 auid, u32 ses, u32 secid);
extern void xfrm_audit_state_add(struct xfrm_state *x, int result,
				 u32 auid, u32 ses, u32 secid);
extern void xfrm_audit_state_delete(struct xfrm_state *x, int result,
				    u32 auid, u32 ses, u32 secid);
extern void xfrm_audit_state_replay_overflow(struct xfrm_state *x,
					     struct sk_buff *skb);
extern void xfrm_audit_state_notfound_simple(struct sk_buff *skb, u16 family);
extern void xfrm_audit_state_notfound(struct sk_buff *skb, u16 family,
				      __be32 net_spi, __be32 net_seq);
extern void xfrm_audit_state_icvfail(struct xfrm_state *x,
				     struct sk_buff *skb, u8 proto);
#else

static inline void xfrm_audit_policy_add(struct xfrm_policy *xp, int result,
				  u32 auid, u32 ses, u32 secid)
{
}

static inline void xfrm_audit_policy_delete(struct xfrm_policy *xp, int result,
				  u32 auid, u32 ses, u32 secid)
{
}

static inline void xfrm_audit_state_add(struct xfrm_state *x, int result,
				 u32 auid, u32 ses, u32 secid)
{
}

static inline void xfrm_audit_state_delete(struct xfrm_state *x, int result,
				    u32 auid, u32 ses, u32 secid)
{
}

static inline void xfrm_audit_state_replay_overflow(struct xfrm_state *x,
					     struct sk_buff *skb)
{
}

static inline void xfrm_audit_state_notfound_simple(struct sk_buff *skb,
				      u16 family)
{
}

static inline void xfrm_audit_state_notfound(struct sk_buff *skb, u16 family,
				      __be32 net_spi, __be32 net_seq)
{
}

static inline void xfrm_audit_state_icvfail(struct xfrm_state *x,
				     struct sk_buff *skb, u8 proto)
{
}
#endif /* CONFIG_AUDITSYSCALL */

static inline void xfrm_pol_hold(struct xfrm_policy *policy)
{
	if (likely(policy != NULL))
		atomic_inc(&policy->refcnt);
}

extern void xfrm_policy_destroy(struct xfrm_policy *policy);

static inline void xfrm_pol_put(struct xfrm_policy *policy)
{
	if (atomic_dec_and_test(&policy->refcnt))
		xfrm_policy_destroy(policy);
}

static inline void xfrm_pols_put(struct xfrm_policy **pols, int npols)
{
	int i;
	for (i = npols - 1; i >= 0; --i)
		xfrm_pol_put(pols[i]);
}

extern void __xfrm_state_destroy(struct xfrm_state *);

static inline void __xfrm_state_put(struct xfrm_state *x)
{
	atomic_dec(&x->refcnt);
}

static inline void xfrm_state_put(struct xfrm_state *x)
{
	if (atomic_dec_and_test(&x->refcnt))
		__xfrm_state_destroy(x);
}

static inline void xfrm_state_hold(struct xfrm_state *x)
{
	atomic_inc(&x->refcnt);
}

static inline bool addr_match(const void *token1, const void *token2,
			      int prefixlen)
{
	const __be32 *a1 = token1;
	const __be32 *a2 = token2;
	int pdw;
	int pbi;

	pdw = prefixlen >> 5;	  /* num of whole u32 in prefix */
	pbi = prefixlen &  0x1f;  /* num of bits in incomplete u32 in prefix */

	if (pdw)
		if (memcmp(a1, a2, pdw << 2))
			return false;

	if (pbi) {
		__be32 mask;

		mask = htonl((0xffffffff) << (32 - pbi));

		if ((a1[pdw] ^ a2[pdw]) & mask)
			return false;
	}

	return true;
}

static __inline__
__be16 xfrm_flowi_sport(const struct flowi *fl, const union flowi_uli *uli)
{
	__be16 port;
	switch(fl->flowi_proto) {
	case IPPROTO_TCP:
	case IPPROTO_UDP:
	case IPPROTO_UDPLITE:
	case IPPROTO_SCTP:
		port = uli->ports.sport;
		break;
	case IPPROTO_ICMP:
	case IPPROTO_ICMPV6:
		port = htons(uli->icmpt.type);
		break;
	case IPPROTO_MH:
		port = htons(uli->mht.type);
		break;
	case IPPROTO_GRE:
		port = htons(ntohl(uli->gre_key) >> 16);
		break;
	default:
		port = 0;	/*XXX*/
	}
	return port;
}

static __inline__
__be16 xfrm_flowi_dport(const struct flowi *fl, const union flowi_uli *uli)
{
	__be16 port;
	switch(fl->flowi_proto) {
	case IPPROTO_TCP:
	case IPPROTO_UDP:
	case IPPROTO_UDPLITE:
	case IPPROTO_SCTP:
		port = uli->ports.dport;
		break;
	case IPPROTO_ICMP:
	case IPPROTO_ICMPV6:
		port = htons(uli->icmpt.code);
		break;
	case IPPROTO_GRE:
		port = htons(ntohl(uli->gre_key) & 0xffff);
		break;
	default:
		port = 0;	/*XXX*/
	}
	return port;
}

extern int xfrm_selector_match(const struct xfrm_selector *sel,
			       const struct flowi *fl,
			       unsigned short family);

#ifdef CONFIG_SECURITY_NETWORK_XFRM
/*	If neither has a context --> match
 * 	Otherwise, both must have a context and the sids, doi, alg must match
 */
static inline int xfrm_sec_ctx_match(struct xfrm_sec_ctx *s1, struct xfrm_sec_ctx *s2)
{
	return ((!s1 && !s2) ||
		(s1 && s2 &&
		 (s1->ctx_sid == s2->ctx_sid) &&
		 (s1->ctx_doi == s2->ctx_doi) &&
		 (s1->ctx_alg == s2->ctx_alg)));
}
#else
static inline int xfrm_sec_ctx_match(struct xfrm_sec_ctx *s1, struct xfrm_sec_ctx *s2)
{
	return 1;
}
#endif

/* A struct encoding bundle of transformations to apply to some set of flow.
 *
 * dst->child points to the next element of bundle.
 * dst->xfrm  points to an instanse of transformer.
 *
 * Due to unfortunate limitations of current routing cache, which we
 * have no time to fix, it mirrors struct rtable and bound to the same
 * routing key, including saddr,daddr. However, we can have many of
 * bundles differing by session id. All the bundles grow from a parent
 * policy rule.
 */
struct xfrm_dst {
	union {
		struct dst_entry	dst;
		struct rtable		rt;
		struct rt6_info		rt6;
	} u;
	struct dst_entry *route;
	struct flow_cache_object flo;
	struct xfrm_policy *pols[XFRM_POLICY_TYPE_MAX];
	int num_pols, num_xfrms;
#ifdef CONFIG_XFRM_SUB_POLICY
	struct flowi *origin;
	struct xfrm_selector *partner;
#endif
	u32 xfrm_genid;
	u32 policy_genid;
	u32 route_mtu_cached;
	u32 child_mtu_cached;
	u32 route_cookie;
	u32 path_cookie;
};

#ifdef CONFIG_XFRM
static inline void xfrm_dst_destroy(struct xfrm_dst *xdst)
{
	xfrm_pols_put(xdst->pols, xdst->num_pols);
	dst_release(xdst->route);
	if (likely(xdst->u.dst.xfrm))
		xfrm_state_put(xdst->u.dst.xfrm);
#ifdef CONFIG_XFRM_SUB_POLICY
	kfree(xdst->origin);
	xdst->origin = NULL;
	kfree(xdst->partner);
	xdst->partner = NULL;
#endif
}
#endif

extern void xfrm_dst_ifdown(struct dst_entry *dst, struct net_device *dev);

struct sec_path {
	atomic_t		refcnt;
	int			len;
	struct xfrm_state	*xvec[XFRM_MAX_DEPTH];
};

static inline struct sec_path *
secpath_get(struct sec_path *sp)
{
	if (sp)
		atomic_inc(&sp->refcnt);
	return sp;
}

extern void __secpath_destroy(struct sec_path *sp);

static inline void
secpath_put(struct sec_path *sp)
{
	if (sp && atomic_dec_and_test(&sp->refcnt))
		__secpath_destroy(sp);
}

extern struct sec_path *secpath_dup(struct sec_path *src);

static inline void
secpath_reset(struct sk_buff *skb)
{
#ifdef CONFIG_XFRM
	secpath_put(skb->sp);
	skb->sp = NULL;
#endif
}

static inline int
xfrm_addr_any(const xfrm_address_t *addr, unsigned short family)
{
	switch (family) {
	case AF_INET:
		return addr->a4 == 0;
	case AF_INET6:
		return ipv6_addr_any((struct in6_addr *)&addr->a6);
	}
	return 0;
}

static inline int
__xfrm4_state_addr_cmp(const struct xfrm_tmpl *tmpl, const struct xfrm_state *x)
{
	return	(tmpl->saddr.a4 &&
		 tmpl->saddr.a4 != x->props.saddr.a4);
}

static inline int
__xfrm6_state_addr_cmp(const struct xfrm_tmpl *tmpl, const struct xfrm_state *x)
{
	return	(!ipv6_addr_any((struct in6_addr*)&tmpl->saddr) &&
		 ipv6_addr_cmp((struct in6_addr *)&tmpl->saddr, (struct in6_addr*)&x->props.saddr));
}

static inline int
xfrm_state_addr_cmp(const struct xfrm_tmpl *tmpl, const struct xfrm_state *x, unsigned short family)
{
	switch (family) {
	case AF_INET:
		return __xfrm4_state_addr_cmp(tmpl, x);
	case AF_INET6:
		return __xfrm6_state_addr_cmp(tmpl, x);
	}
	return !0;
}

#ifdef CONFIG_XFRM
extern int __xfrm_policy_check(struct sock *, int dir, struct sk_buff *skb, unsigned short family);

static inline int __xfrm_policy_check2(struct sock *sk, int dir,
				       struct sk_buff *skb,
				       unsigned int family, int reverse)
{
	struct net *net = dev_net(skb->dev);
	int ndir = dir | (reverse ? XFRM_POLICY_MASK + 1 : 0);

	if (sk && sk->sk_policy[XFRM_POLICY_IN])
		return __xfrm_policy_check(sk, ndir, skb, family);

	return	(!net->xfrm.policy_count[dir] && !skb->sp) ||
		(skb_dst(skb)->flags & DST_NOPOLICY) ||
		__xfrm_policy_check(sk, ndir, skb, family);
}

static inline int xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb, unsigned short family)
{
	return __xfrm_policy_check2(sk, dir, skb, family, 0);
}

static inline int xfrm4_policy_check(struct sock *sk, int dir, struct sk_buff *skb)
{
	return xfrm_policy_check(sk, dir, skb, AF_INET);
}

static inline int xfrm6_policy_check(struct sock *sk, int dir, struct sk_buff *skb)
{
	return xfrm_policy_check(sk, dir, skb, AF_INET6);
}

static inline int xfrm4_policy_check_reverse(struct sock *sk, int dir,
					     struct sk_buff *skb)
{
	return __xfrm_policy_check2(sk, dir, skb, AF_INET, 1);
}

static inline int xfrm6_policy_check_reverse(struct sock *sk, int dir,
					     struct sk_buff *skb)
{
	return __xfrm_policy_check2(sk, dir, skb, AF_INET6, 1);
}

extern int __xfrm_decode_session(struct sk_buff *skb, struct flowi *fl,
				 unsigned int family, int reverse);

static inline int xfrm_decode_session(struct sk_buff *skb, struct flowi *fl,
				      unsigned int family)
{
	return __xfrm_decode_session(skb, fl, family, 0);
}

static inline int xfrm_decode_session_reverse(struct sk_buff *skb,
					      struct flowi *fl,
					      unsigned int family)
{
	return __xfrm_decode_session(skb, fl, family, 1);
}

extern int __xfrm_route_forward(struct sk_buff *skb, unsigned short family);

static inline int xfrm_route_forward(struct sk_buff *skb, unsigned short family)
{
	struct net *net = dev_net(skb->dev);

	return	!net->xfrm.policy_count[XFRM_POLICY_OUT] ||
		(skb_dst(skb)->flags & DST_NOXFRM) ||
		__xfrm_route_forward(skb, family);
}

static inline int xfrm4_route_forward(struct sk_buff *skb)
{
	return xfrm_route_forward(skb, AF_INET);
}

static inline int xfrm6_route_forward(struct sk_buff *skb)
{
	return xfrm_route_forward(skb, AF_INET6);
}

extern int __xfrm_sk_clone_policy(struct sock *sk);

static inline int xfrm_sk_clone_policy(struct sock *sk)
{
	if (unlikely(sk->sk_policy[0] || sk->sk_policy[1]))
		return __xfrm_sk_clone_policy(sk);
	return 0;
}

extern int xfrm_policy_delete(struct xfrm_policy *pol, int dir);

static inline void xfrm_sk_free_policy(struct sock *sk)
{
	if (unlikely(sk->sk_policy[0] != NULL)) {
		xfrm_policy_delete(sk->sk_policy[0], XFRM_POLICY_MAX);
		sk->sk_policy[0] = NULL;
	}
	if (unlikely(sk->sk_policy[1] != NULL)) {
		xfrm_policy_delete(sk->sk_policy[1], XFRM_POLICY_MAX+1);
		sk->sk_policy[1] = NULL;
	}
}

#else

static inline void xfrm_sk_free_policy(struct sock *sk) {}
static inline int xfrm_sk_clone_policy(struct sock *sk) { return 0; }
static inline int xfrm6_route_forward(struct sk_buff *skb) { return 1; }  
static inline int xfrm4_route_forward(struct sk_buff *skb) { return 1; } 
static inline int xfrm6_policy_check(struct sock *sk, int dir, struct sk_buff *skb)
{ 
	return 1; 
} 
static inline int xfrm4_policy_check(struct sock *sk, int dir, struct sk_buff *skb)
{
	return 1;
}
static inline int xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb, unsigned short family)
{
	return 1;
}
static inline int xfrm_decode_session_reverse(struct sk_buff *skb,
					      struct flowi *fl,
					      unsigned int family)
{
	return -ENOSYS;
}
static inline int xfrm4_policy_check_reverse(struct sock *sk, int dir,
					     struct sk_buff *skb)
{
	return 1;
}
static inline int xfrm6_policy_check_reverse(struct sock *sk, int dir,
					     struct sk_buff *skb)
{
	return 1;
}
#endif

static __inline__
xfrm_address_t *xfrm_flowi_daddr(const struct flowi *fl, unsigned short family)
{
	switch (family){
	case AF_INET:
		return (xfrm_address_t *)&fl->u.ip4.daddr;
	case AF_INET6:
		return (xfrm_address_t *)&fl->u.ip6.daddr;
	}
	return NULL;
}

static __inline__
xfrm_address_t *xfrm_flowi_saddr(const struct flowi *fl, unsigned short family)
{
	switch (family){
	case AF_INET:
		return (xfrm_address_t *)&fl->u.ip4.saddr;
	case AF_INET6:
		return (xfrm_address_t *)&fl->u.ip6.saddr;
	}
	return NULL;
}

static __inline__
void xfrm_flowi_addr_get(const struct flowi *fl,
			 xfrm_address_t *saddr, xfrm_address_t *daddr,
			 unsigned short family)
{
	switch(family) {
	case AF_INET:
		memcpy(&saddr->a4, &fl->u.ip4.saddr, sizeof(saddr->a4));
		memcpy(&daddr->a4, &fl->u.ip4.daddr, sizeof(daddr->a4));
		break;
	case AF_INET6:
		ipv6_addr_copy((struct in6_addr *)&saddr->a6, &fl->u.ip6.saddr);
		ipv6_addr_copy((struct in6_addr *)&daddr->a6, &fl->u.ip6.daddr);
		break;
	}
}

static __inline__ int
__xfrm4_state_addr_check(const struct xfrm_state *x,
			 const xfrm_address_t *daddr, const xfrm_address_t *saddr)
{
	if (daddr->a4 == x->id.daddr.a4 &&
	    (saddr->a4 == x->props.saddr.a4 || !saddr->a4 || !x->props.saddr.a4))
		return 1;
	return 0;
}

static __inline__ int
__xfrm6_state_addr_check(const struct xfrm_state *x,
			 const xfrm_address_t *daddr, const xfrm_address_t *saddr)
{
	if (!ipv6_addr_cmp((struct in6_addr *)daddr, (struct in6_addr *)&x->id.daddr) &&
	    (!ipv6_addr_cmp((struct in6_addr *)saddr, (struct in6_addr *)&x->props.saddr)|| 
	     ipv6_addr_any((struct in6_addr *)saddr) || 
	     ipv6_addr_any((struct in6_addr *)&x->props.saddr)))
		return 1;
	return 0;
}

static __inline__ int
xfrm_state_addr_check(const struct xfrm_state *x,
		      const xfrm_address_t *daddr, const xfrm_address_t *saddr,
		      unsigned short family)
{
	switch (family) {
	case AF_INET:
		return __xfrm4_state_addr_check(x, daddr, saddr);
	case AF_INET6:
		return __xfrm6_state_addr_check(x, daddr, saddr);
	}
	return 0;
}

static __inline__ int
xfrm_state_addr_flow_check(const struct xfrm_state *x, const struct flowi *fl,
			   unsigned short family)
{
	switch (family) {
	case AF_INET:
		return __xfrm4_state_addr_check(x,
						(const xfrm_address_t *)&fl->u.ip4.daddr,
						(const xfrm_address_t *)&fl->u.ip4.saddr);
	case AF_INET6:
		return __xfrm6_state_addr_check(x,
						(const xfrm_address_t *)&fl->u.ip6.daddr,
						(const xfrm_address_t *)&fl->u.ip6.saddr);
	}
	return 0;
}

static inline int xfrm_state_kern(const struct xfrm_state *x)
{
	return atomic_read(&x->tunnel_users);
}

static inline int xfrm_id_proto_match(u8 proto, u8 userproto)
{
	return (!userproto || proto == userproto ||
		(userproto == IPSEC_PROTO_ANY && (proto == IPPROTO_AH ||
						  proto == IPPROTO_ESP ||
						  proto == IPPROTO_COMP)));
}

/*
 * xfrm algorithm information
 */
struct xfrm_algo_aead_info {
	u16 icv_truncbits;
};

struct xfrm_algo_auth_info {
	u16 icv_truncbits;
	u16 icv_fullbits;
};

struct xfrm_algo_encr_info {
	u16 blockbits;
	u16 defkeybits;
};

struct xfrm_algo_comp_info {
	u16 threshold;
};

struct xfrm_algo_desc {
	char *name;
	char *compat;
	u8 available:1;
	union {
		struct xfrm_algo_aead_info aead;
		struct xfrm_algo_auth_info auth;
		struct xfrm_algo_encr_info encr;
		struct xfrm_algo_comp_info comp;
	} uinfo;
	struct sadb_alg desc;
};

/* XFRM tunnel handlers.  */
struct xfrm_tunnel {
	int (*handler)(struct sk_buff *skb);
	int (*err_handler)(struct sk_buff *skb, u32 info);

	struct xfrm_tunnel __rcu *next;
	int priority;
};

struct xfrm6_tunnel {
	int (*handler)(struct sk_buff *skb);
	int (*err_handler)(struct sk_buff *skb, struct inet6_skb_parm *opt,
			   u8 type, u8 code, int offset, __be32 info);
	struct xfrm6_tunnel __rcu *next;
	int priority;
};

extern void xfrm_init(void);
extern void xfrm4_init(int rt_hash_size);
extern int xfrm_state_init(struct net *net);
extern void xfrm_state_fini(struct net *net);
extern void xfrm4_state_init(void);
#ifdef CONFIG_XFRM
extern int xfrm6_init(void);
extern void xfrm6_fini(void);
extern int xfrm6_state_init(void);
extern void xfrm6_state_fini(void);
#else
static inline int xfrm6_init(void)
{
	return 0;
}
static inline void xfrm6_fini(void)
{
	;
}
#endif

#ifdef CONFIG_XFRM_STATISTICS
extern int xfrm_proc_init(struct net *net);
extern void xfrm_proc_fini(struct net *net);
#endif

extern int xfrm_sysctl_init(struct net *net);
#ifdef CONFIG_SYSCTL
extern void xfrm_sysctl_fini(struct net *net);
#else
static inline void xfrm_sysctl_fini(struct net *net)
{
}
#endif

extern void xfrm_state_walk_init(struct xfrm_state_walk *walk, u8 proto);
extern int xfrm_state_walk(struct net *net, struct xfrm_state_walk *walk,
			   int (*func)(struct xfrm_state *, int, void*), void *);
extern void xfrm_state_walk_done(struct xfrm_state_walk *walk);
extern struct xfrm_state *xfrm_state_alloc(struct net *net);
extern struct xfrm_state *xfrm_state_find(const xfrm_address_t *daddr,
					  const xfrm_address_t *saddr,
					  const struct flowi *fl,
					  struct xfrm_tmpl *tmpl,
					  struct xfrm_policy *pol, int *err,
					  unsigned short family);
extern struct xfrm_state *xfrm_stateonly_find(struct net *net, u32 mark,
					       xfrm_address_t *daddr,
					       xfrm_address_t *saddr,
					       unsigned short family,
					       u8 mode, u8 proto, u32 reqid);
extern int xfrm_state_check_expire(struct xfrm_state *x);
extern void xfrm_state_insert(struct xfrm_state *x);
extern int xfrm_state_add(struct xfrm_state *x);
extern int xfrm_state_update(struct xfrm_state *x);
extern struct xfrm_state *xfrm_state_lookup(struct net *net, u32 mark,
					    const xfrm_address_t *daddr, __be32 spi,
					    u8 proto, unsigned short family);
extern struct xfrm_state *xfrm_state_lookup_byaddr(struct net *net, u32 mark,
						   const xfrm_address_t *daddr,
						   const xfrm_address_t *saddr,
						   u8 proto,
						   unsigned short family);
#ifdef CONFIG_XFRM_SUB_POLICY
extern int xfrm_tmpl_sort(struct xfrm_tmpl **dst, struct xfrm_tmpl **src,
			  int n, unsigned short family);
extern int xfrm_state_sort(struct xfrm_state **dst, struct xfrm_state **src,
			   int n, unsigned short family);
#else
static inline int xfrm_tmpl_sort(struct xfrm_tmpl **dst, struct xfrm_tmpl **src,
				 int n, unsigned short family)
{
	return -ENOSYS;
}

static inline int xfrm_state_sort(struct xfrm_state **dst, struct xfrm_state **src,
				  int n, unsigned short family)
{
	return -ENOSYS;
}
#endif

struct xfrmk_sadinfo {
	u32 sadhcnt; /* current hash bkts */
	u32 sadhmcnt; /* max allowed hash bkts */
	u32 sadcnt; /* current running count */
};

struct xfrmk_spdinfo {
	u32 incnt;
	u32 outcnt;
	u32 fwdcnt;
	u32 inscnt;
	u32 outscnt;
	u32 fwdscnt;
	u32 spdhcnt;
	u32 spdhmcnt;
};

extern struct xfrm_state *xfrm_find_acq_byseq(struct net *net, u32 mark,
					      u32 seq);
extern int xfrm_state_delete(struct xfrm_state *x);
extern int xfrm_state_flush(struct net *net, u8 proto, struct xfrm_audit *audit_info);
extern void xfrm_sad_getinfo(struct net *net, struct xfrmk_sadinfo *si);
extern void xfrm_spd_getinfo(struct net *net, struct xfrmk_spdinfo *si);
extern int xfrm_replay_check(struct xfrm_state *x,
			     struct sk_buff *skb, __be32 seq);
extern void xfrm_replay_advance(struct xfrm_state *x, __be32 seq);
extern void xfrm_replay_notify(struct xfrm_state *x, int event);
extern int xfrm_state_mtu(struct xfrm_state *x, int mtu);
extern int xfrm_init_state(struct xfrm_state *x);
extern int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb);
extern int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi,
		      int encap_type);
extern int xfrm_input_resume(struct sk_buff *skb, int nexthdr);
extern int xfrm_output_resume(struct sk_buff *skb, int err);
extern int xfrm_output(struct sk_buff *skb);
extern int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb);
extern int xfrm4_extract_header(struct sk_buff *skb);
extern int xfrm4_extract_input(struct xfrm_state *x, struct sk_buff *skb);
extern int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
			   int encap_type);
extern int xfrm4_transport_finish(struct sk_buff *skb, int async);
extern int xfrm4_rcv(struct sk_buff *skb);

static inline int xfrm4_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi)
{
	return xfrm4_rcv_encap(skb, nexthdr, spi, 0);
}

extern int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb);
extern int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb);
extern int xfrm4_output(struct sk_buff *skb);
extern int xfrm4_tunnel_register(struct xfrm_tunnel *handler, unsigned short family);
extern int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler, unsigned short family);
extern int xfrm6_extract_header(struct sk_buff *skb);
extern int xfrm6_extract_input(struct xfrm_state *x, struct sk_buff *skb);
extern int xfrm6_rcv_spi(struct sk_buff *skb, int nexthdr, __be32 spi);
extern int xfrm6_transport_finish(struct sk_buff *skb, int async);
extern int xfrm6_rcv(struct sk_buff *skb);
extern int xfrm6_input_addr(struct sk_buff *skb, xfrm_address_t *daddr,
			    xfrm_address_t *saddr, u8 proto);
extern int xfrm6_tunnel_register(struct xfrm6_tunnel *handler, unsigned short family);
extern int xfrm6_tunnel_deregister(struct xfrm6_tunnel *handler, unsigned short family);
extern __be32 xfrm6_tunnel_alloc_spi(struct net *net, xfrm_address_t *saddr);
extern __be32 xfrm6_tunnel_spi_lookup(struct net *net, xfrm_address_t *saddr);
extern int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb);
extern int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb);
extern int xfrm6_output(struct sk_buff *skb);
extern int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
				 u8 **prevhdr);

#ifdef CONFIG_XFRM
extern int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb);
extern int xfrm_user_policy(struct sock *sk, int optname, u8 __user *optval, int optlen);
#else
static inline int xfrm_user_policy(struct sock *sk, int optname, u8 __user *optval, int optlen)
{
 	return -ENOPROTOOPT;
} 

static inline int xfrm4_udp_encap_rcv(struct sock *sk, struct sk_buff *skb)
{
 	/* should not happen */
 	kfree_skb(skb);
	return 0;
}
#endif

struct xfrm_policy *xfrm_policy_alloc(struct net *net, gfp_t gfp);

extern void xfrm_policy_walk_init(struct xfrm_policy_walk *walk, u8 type);
extern int xfrm_policy_walk(struct net *net, struct xfrm_policy_walk *walk,
	int (*func)(struct xfrm_policy *, int, int, void*), void *);
extern void xfrm_policy_walk_done(struct xfrm_policy_walk *walk);
int xfrm_policy_insert(int dir, struct xfrm_policy *policy, int excl);
struct xfrm_policy *xfrm_policy_bysel_ctx(struct net *net, u32 mark,
					  u8 type, int dir,
					  struct xfrm_selector *sel,
					  struct xfrm_sec_ctx *ctx, int delete,
					  int *err);
struct xfrm_policy *xfrm_policy_byid(struct net *net, u32 mark, u8, int dir, u32 id, int delete, int *err);
int xfrm_policy_flush(struct net *net, u8 type, struct xfrm_audit *audit_info);
u32 xfrm_get_acqseq(void);
extern int xfrm_alloc_spi(struct xfrm_state *x, u32 minspi, u32 maxspi);
struct xfrm_state *xfrm_find_acq(struct net *net, struct xfrm_mark *mark,
				 u8 mode, u32 reqid, u8 proto,
				 const xfrm_address_t *daddr,
				 const xfrm_address_t *saddr, int create,
				 unsigned short family);
extern int xfrm_sk_policy_insert(struct sock *sk, int dir, struct xfrm_policy *pol);

#ifdef CONFIG_XFRM_MIGRATE
extern int km_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
		      const struct xfrm_migrate *m, int num_bundles,
		      const struct xfrm_kmaddress *k);
extern struct xfrm_state * xfrm_migrate_state_find(struct xfrm_migrate *m);
extern struct xfrm_state * xfrm_state_migrate(struct xfrm_state *x,
					      struct xfrm_migrate *m);
extern int xfrm_migrate(const struct xfrm_selector *sel, u8 dir, u8 type,
			struct xfrm_migrate *m, int num_bundles,
			struct xfrm_kmaddress *k);
#endif

extern int km_new_mapping(struct xfrm_state *x, xfrm_address_t *ipaddr, __be16 sport);
extern void km_policy_expired(struct xfrm_policy *pol, int dir, int hard, u32 pid);
extern int km_report(struct net *net, u8 proto, struct xfrm_selector *sel, xfrm_address_t *addr);

extern void xfrm_input_init(void);
extern int xfrm_parse_spi(struct sk_buff *skb, u8 nexthdr, __be32 *spi, __be32 *seq);

extern void xfrm_probe_algs(void);
extern int xfrm_count_auth_supported(void);
extern int xfrm_count_enc_supported(void);
extern struct xfrm_algo_desc *xfrm_aalg_get_byidx(unsigned int idx);
extern struct xfrm_algo_desc *xfrm_ealg_get_byidx(unsigned int idx);
extern struct xfrm_algo_desc *xfrm_aalg_get_byid(int alg_id);
extern struct xfrm_algo_desc *xfrm_ealg_get_byid(int alg_id);
extern struct xfrm_algo_desc *xfrm_calg_get_byid(int alg_id);
extern struct xfrm_algo_desc *xfrm_aalg_get_byname(const char *name, int probe);
extern struct xfrm_algo_desc *xfrm_ealg_get_byname(const char *name, int probe);
extern struct xfrm_algo_desc *xfrm_calg_get_byname(const char *name, int probe);
extern struct xfrm_algo_desc *xfrm_aead_get_byname(const char *name, int icv_len,
						   int probe);

struct hash_desc;
struct scatterlist;
typedef int (icv_update_fn_t)(struct hash_desc *, struct scatterlist *,
			      unsigned int);

static inline int xfrm_addr_cmp(const xfrm_address_t *a,
				const xfrm_address_t *b,
				int family)
{
	switch (family) {
	default:
	case AF_INET:
		return (__force u32)a->a4 - (__force u32)b->a4;
	case AF_INET6:
		return ipv6_addr_cmp((struct in6_addr *)a,
				     (struct in6_addr *)b);
	}
}

static inline int xfrm_policy_id2dir(u32 index)
{
	return index & 7;
}

#ifdef CONFIG_XFRM
static inline int xfrm_aevent_is_on(struct net *net)
{
	struct sock *nlsk;
	int ret = 0;

	rcu_read_lock();
	nlsk = rcu_dereference(net->xfrm.nlsk);
	if (nlsk)
		ret = netlink_has_listeners(nlsk, XFRMNLGRP_AEVENTS);
	rcu_read_unlock();
	return ret;
}
#endif

static inline int xfrm_alg_len(const struct xfrm_algo *alg)
{
	return sizeof(*alg) + ((alg->alg_key_len + 7) / 8);
}

static inline int xfrm_alg_auth_len(const struct xfrm_algo_auth *alg)
{
	return sizeof(*alg) + ((alg->alg_key_len + 7) / 8);
}

static inline int xfrm_replay_state_esn_len(struct xfrm_replay_state_esn *replay_esn)
{
	return sizeof(*replay_esn) + replay_esn->bmp_len * sizeof(__u32);
}

#ifdef CONFIG_XFRM_MIGRATE
static inline struct xfrm_algo *xfrm_algo_clone(struct xfrm_algo *orig)
{
	return kmemdup(orig, xfrm_alg_len(orig), GFP_KERNEL);
}

static inline struct xfrm_algo_auth *xfrm_algo_auth_clone(struct xfrm_algo_auth *orig)
{
	return kmemdup(orig, xfrm_alg_auth_len(orig), GFP_KERNEL);
}

static inline void xfrm_states_put(struct xfrm_state **states, int n)
{
	int i;
	for (i = 0; i < n; i++)
		xfrm_state_put(*(states + i));
}

static inline void xfrm_states_delete(struct xfrm_state **states, int n)
{
	int i;
	for (i = 0; i < n; i++)
		xfrm_state_delete(*(states + i));
}
#endif

#ifdef CONFIG_XFRM
static inline struct xfrm_state *xfrm_input_state(struct sk_buff *skb)
{
	return skb->sp->xvec[skb->sp->len - 1];
}
#endif

static inline int xfrm_mark_get(struct nlattr **attrs, struct xfrm_mark *m)
{
	if (attrs[XFRMA_MARK])
		memcpy(m, nla_data(attrs[XFRMA_MARK]), sizeof(struct xfrm_mark));
	else
		m->v = m->m = 0;

	return m->v & m->m;
}

static inline int xfrm_mark_put(struct sk_buff *skb, const struct xfrm_mark *m)
{
	if (m->m | m->v)
		NLA_PUT(skb, XFRMA_MARK, sizeof(struct xfrm_mark), m);
	return 0;

nla_put_failure:
	return -1;
}

#endif	/* _NET_XFRM_H */