/*-
 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
 *
 * Copyright (c) 2004 Luigi Rizzo, Alessandro Cerri. All rights reserved.
 * Copyright (c) 2004-2008 Qing Li. All rights reserved.
 * Copyright (c) 2008 Kip Macy. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: releng/12.0/sys/net/if_llatbl.h 334193 2018-05-24 23:21:23Z mmacy $");

#ifndef	_NET_IF_LLATBL_H_
#define	_NET_IF_LLATBL_H_

#include <sys/_rwlock.h>
#include <netinet/in.h>
#include <sys/epoch.h>
#include <sys/ck.h>

struct ifnet;
struct sysctl_req;
struct rt_msghdr;
struct rt_addrinfo;
struct llentry;
CK_LIST_HEAD(llentries, llentry);

#define	LLE_MAX_LINKHDR		24	/* Full IB header */
/*
 * Code referencing llentry must at least hold
 * a shared lock
 */
struct llentry {
	CK_LIST_ENTRY(llentry)	 lle_next;
	union {
		struct in_addr	addr4;
		struct in6_addr	addr6;
	} r_l3addr;
	char			r_linkdata[LLE_MAX_LINKHDR]; /* L2 data */
	uint8_t			r_hdrlen;	/* length for LL header */
	uint8_t			spare0[3];
	uint16_t		r_flags;	/* LLE runtime flags */
	uint16_t		r_skip_req;	/* feedback from fast path */

	struct lltable		 *lle_tbl;
	struct llentries	 *lle_head;
	void			(*lle_free)(struct llentry *);
	struct mbuf		 *la_hold;
	int			 la_numheld;  /* # of packets currently held */
	time_t			 la_expire;
	uint16_t		 la_flags;
	uint16_t		 la_asked;
	uint16_t		 la_preempt;
	int16_t			 ln_state;	/* IPv6 has ND6_LLINFO_NOSTATE == -2 */
	uint16_t		 ln_router;
	time_t			 ln_ntick;
	time_t			lle_remtime;	/* Real time remaining */
	time_t			lle_hittime;	/* Time when r_skip_req was unset */
	int			 lle_refcnt;
	char			*ll_addr;	/* link-layer address */

	CK_LIST_ENTRY(llentry)	lle_chain;	/* chain of deleted items */
	struct callout		lle_timer;
	struct rwlock		 lle_lock;
	struct mtx		req_mtx;
	struct epoch_context lle_epoch_ctx;
};

#define	LLE_WLOCK(lle)		rw_wlock(&(lle)->lle_lock)
#define	LLE_RLOCK(lle)		rw_rlock(&(lle)->lle_lock)
#define	LLE_WUNLOCK(lle)	rw_wunlock(&(lle)->lle_lock)
#define	LLE_RUNLOCK(lle)	rw_runlock(&(lle)->lle_lock)
#define	LLE_DOWNGRADE(lle)	rw_downgrade(&(lle)->lle_lock)
#define	LLE_TRY_UPGRADE(lle)	rw_try_upgrade(&(lle)->lle_lock)
#define	LLE_LOCK_INIT(lle)	rw_init_flags(&(lle)->lle_lock, "lle", RW_DUPOK)
#define	LLE_LOCK_DESTROY(lle)	rw_destroy(&(lle)->lle_lock)
#define	LLE_WLOCK_ASSERT(lle)	rw_assert(&(lle)->lle_lock, RA_WLOCKED)

#define	LLE_REQ_INIT(lle)	mtx_init(&(lle)->req_mtx, "lle req", \
	NULL, MTX_DEF)
#define	LLE_REQ_DESTROY(lle)	mtx_destroy(&(lle)->req_mtx)
#define	LLE_REQ_LOCK(lle)	mtx_lock(&(lle)->req_mtx)
#define	LLE_REQ_UNLOCK(lle)	mtx_unlock(&(lle)->req_mtx)

#define LLE_IS_VALID(lle)	(((lle) != NULL) && ((lle) != (void *)-1))

#define	LLE_ADDREF(lle) do {					\
	LLE_WLOCK_ASSERT(lle);					\
	KASSERT((lle)->lle_refcnt >= 0,				\
	    ("negative refcnt %d on lle %p",			\
	    (lle)->lle_refcnt, (lle)));				\
	(lle)->lle_refcnt++;					\
} while (0)

#define	LLE_REMREF(lle)	do {					\
	LLE_WLOCK_ASSERT(lle);					\
	KASSERT((lle)->lle_refcnt > 0,				\
	    ("bogus refcnt %d on lle %p",			\
	    (lle)->lle_refcnt, (lle)));				\
	(lle)->lle_refcnt--;					\
} while (0)

#define	LLE_FREE_LOCKED(lle) do {				\
	if ((lle)->lle_refcnt == 1)				\
		(lle)->lle_free(lle);				\
	else {							\
		LLE_REMREF(lle);				\
		LLE_WUNLOCK(lle);				\
	}							\
	/* guard against invalid refs */			\
	(lle) = NULL;						\
} while (0)

#define	LLE_FREE(lle) do {					\
	LLE_WLOCK(lle);						\
	LLE_FREE_LOCKED(lle);					\
} while (0)

typedef	struct llentry *(llt_lookup_t)(struct lltable *, u_int flags,
    const struct sockaddr *l3addr);
typedef	struct llentry *(llt_alloc_t)(struct lltable *, u_int flags,
    const struct sockaddr *l3addr);
typedef	void (llt_delete_t)(struct lltable *, struct llentry *);
typedef void (llt_prefix_free_t)(struct lltable *,
    const struct sockaddr *addr, const struct sockaddr *mask, u_int flags);
typedef int (llt_dump_entry_t)(struct lltable *, struct llentry *,
    struct sysctl_req *);
typedef uint32_t (llt_hash_t)(const struct llentry *, uint32_t);
typedef int (llt_match_prefix_t)(const struct sockaddr *,
    const struct sockaddr *, u_int, struct llentry *);
typedef void (llt_free_entry_t)(struct lltable *, struct llentry *);
typedef void (llt_fill_sa_entry_t)(const struct llentry *, struct sockaddr *);
typedef void (llt_free_tbl_t)(struct lltable *);
typedef void (llt_link_entry_t)(struct lltable *, struct llentry *);
typedef void (llt_unlink_entry_t)(struct llentry *);
typedef void (llt_mark_used_t)(struct llentry *);

typedef int (llt_foreach_cb_t)(struct lltable *, struct llentry *, void *);
typedef int (llt_foreach_entry_t)(struct lltable *, llt_foreach_cb_t *, void *);

struct lltable {
	SLIST_ENTRY(lltable)	llt_link;
	int			llt_af;
	int			llt_hsize;
	struct llentries	*lle_head;
	struct ifnet		*llt_ifp;

	llt_lookup_t		*llt_lookup;
	llt_alloc_t		*llt_alloc_entry;
	llt_delete_t		*llt_delete_entry;
	llt_prefix_free_t	*llt_prefix_free;
	llt_dump_entry_t	*llt_dump_entry;
	llt_hash_t		*llt_hash;
	llt_match_prefix_t	*llt_match_prefix;
	llt_free_entry_t	*llt_free_entry;
	llt_foreach_entry_t	*llt_foreach_entry;
	llt_link_entry_t	*llt_link_entry;
	llt_unlink_entry_t	*llt_unlink_entry;
	llt_fill_sa_entry_t	*llt_fill_sa_entry;
	llt_free_tbl_t		*llt_free_tbl;
	llt_mark_used_t		*llt_mark_used;
};

MALLOC_DECLARE(M_LLTABLE);

/*
 * LLentry flags
 */
#define	LLE_DELETED	0x0001	/* entry must be deleted */
#define	LLE_STATIC	0x0002	/* entry is static */
#define	LLE_IFADDR	0x0004	/* entry is interface addr */
#define	LLE_VALID	0x0008	/* ll_addr is valid */
#define	LLE_REDIRECT	0x0010	/* installed by redirect; has host rtentry */
#define	LLE_PUB		0x0020	/* publish entry ??? */
#define	LLE_LINKED	0x0040	/* linked to lookup structure */
/* LLE request flags */
#define	LLE_EXCLUSIVE	0x2000	/* return lle xlocked  */
#define	LLE_UNLOCKED	0x4000	/* return lle unlocked */
#define	LLE_ADDRONLY	0x4000	/* return lladdr instead of full header */
#define	LLE_CREATE	0x8000	/* hint to avoid lle lookup */

/* LLE flags used by fastpath code */
#define	RLLE_VALID	0x0001		/* entry is valid */
#define	RLLE_IFADDR	LLE_IFADDR	/* entry is ifaddr */

#define LLATBL_HASH(key, mask) \
	(((((((key >> 8) ^ key) >> 8) ^ key) >> 8) ^ key) & mask)

struct lltable *lltable_allocate_htbl(uint32_t hsize);
void		lltable_free(struct lltable *);
void		lltable_link(struct lltable *llt);
void		lltable_prefix_free(int, struct sockaddr *,
		    struct sockaddr *, u_int);
#if 0
void		lltable_drain(int);
#endif
int		lltable_sysctl_dumparp(int, struct sysctl_req *);

size_t		llentry_free(struct llentry *);
struct llentry  *llentry_alloc(struct ifnet *, struct lltable *,
		    struct sockaddr_storage *);

/* helper functions */
size_t lltable_drop_entry_queue(struct llentry *);
void lltable_set_entry_addr(struct ifnet *ifp, struct llentry *lle,
    const char *linkhdr, size_t linkhdrsize, int lladdr_off);
int lltable_try_set_entry_addr(struct ifnet *ifp, struct llentry *lle,
    const char *linkhdr, size_t linkhdrsize, int lladdr_off);

int lltable_calc_llheader(struct ifnet *ifp, int family, char *lladdr,
    char *buf, size_t *bufsize, int *lladdr_off);
void lltable_update_ifaddr(struct lltable *llt);
struct llentry *lltable_alloc_entry(struct lltable *llt, u_int flags,
    const struct sockaddr *l4addr);
void lltable_free_entry(struct lltable *llt, struct llentry *lle);
int lltable_delete_addr(struct lltable *llt, u_int flags,
    const struct sockaddr *l3addr);
void lltable_link_entry(struct lltable *llt, struct llentry *lle);
void lltable_unlink_entry(struct lltable *llt, struct llentry *lle);
void lltable_fill_sa_entry(const struct llentry *lle, struct sockaddr *sa);
struct ifnet *lltable_get_ifp(const struct lltable *llt);
int lltable_get_af(const struct lltable *llt);

int lltable_foreach_lle(struct lltable *llt, llt_foreach_cb_t *f,
    void *farg);
/*
 * Generic link layer address lookup function.
 */
static __inline struct llentry *
lla_lookup(struct lltable *llt, u_int flags, const struct sockaddr *l3addr)
{

	return (llt->llt_lookup(llt, flags, l3addr));
}

/*
 * Notify the LLE code that the entry was used by datapath.
 */
static __inline void
llentry_mark_used(struct llentry *lle)
{

	if (lle->r_skip_req == 0)
		return;
	if ((lle->r_flags & RLLE_VALID) != 0)
		lle->lle_tbl->llt_mark_used(lle);
}

int		lla_rt_output(struct rt_msghdr *, struct rt_addrinfo *);

#include <sys/eventhandler.h>
enum {
	LLENTRY_RESOLVED,
	LLENTRY_TIMEDOUT,
	LLENTRY_DELETED,
	LLENTRY_EXPIRED,
};
typedef void (*lle_event_fn)(void *, struct llentry *, int);
EVENTHANDLER_DECLARE(lle_event, lle_event_fn);
#endif  /* _NET_IF_LLATBL_H_ */
