/*	$NetBSD: if_llatbl.h,v 1.17 2019/07/18 06:47:10 ozaki-r Exp $	*/
/*
 * 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.
 * Copyright (c) 2015 The NetBSD Foundation, Inc.
 * 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>

#ifndef	_NET_IF_LLATBL_H_
#define	_NET_IF_LLATBL_H_

#if defined(_KERNEL_OPT)
#include "opt_gateway.h"
#endif

#include <sys/rwlock.h>
#include <sys/syslog.h>

#include <netinet/in.h>

struct ifnet;
struct sysctl_req;
struct rt_msghdr;
struct rt_addrinfo;
struct rt_walkarg;

struct llentry;
LIST_HEAD(llentries, llentry);

extern krwlock_t lltable_rwlock;
#define	LLTABLE_RLOCK()		rw_enter(&lltable_rwlock, RW_READER)
#define	LLTABLE_RUNLOCK()	rw_exit(&lltable_rwlock)
#define	LLTABLE_WLOCK()		rw_enter(&lltable_rwlock, RW_WRITER)
#define	LLTABLE_WUNLOCK()	rw_exit(&lltable_rwlock)
#define	LLTABLE_LOCK_ASSERT()	KASSERT(rw_lock_held(&lltable_rwlock))

/*
 * Code referencing llentry must at least hold
 * a shared lock
 */
struct llentry {
	LIST_ENTRY(llentry)	 lle_next;
	union {
		struct in_addr	addr4;
		struct in6_addr	addr6;
	} r_l3addr;
	union {
		uint64_t	mac_aligned;
		uint16_t	mac16[3];
		uint8_t		mac8[20];	/* IB needs 20 bytes. */
	} ll_addr;
	uint32_t		spare0;
	uint64_t		spare1;

	struct lltable		 *lle_tbl;
	struct llentries	 *lle_head;
	void			(*lle_free)(struct llentry *);
	void			(*lle_ll_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;
	uint16_t		 ln_byhint;
	int16_t			 ln_state;	/* IPv6 has ND6_LLINFO_NOSTATE == -2 */
	uint16_t		 ln_router;
	time_t			 ln_ntick;
	int			 lle_refcnt;

	LIST_ENTRY(llentry)	lle_chain;	/* chain of deleted items */
	struct callout		lle_timer;
	krwlock_t		lle_lock;

#ifdef __NetBSD__
#define	la_timer	lle_timer
#define	ln_timer_ch	lle_timer
#define	ln_expire	la_expire
#define	ln_asked	la_asked
#define	ln_hold		la_hold
	void			*la_opaque;	/* For tokenring */
#endif
};


#if 0
#define LLE_LOCK_TRACE(t, lle)	log(LOG_DEBUG, \
				    "%s:%d: LOCK(" #t "): lle=%p\n", \
				    __func__, __LINE__, (lle))
#else
#define LLE_LOCK_TRACE(t, lle)	do {} while (0)
#endif

#define	LLE_WLOCK(lle)		do { \
					LLE_LOCK_TRACE(WL, (lle)); \
					rw_enter(&(lle)->lle_lock, RW_WRITER); \
				} while (0)
#define	LLE_RLOCK(lle)		do { \
					LLE_LOCK_TRACE(RL, (lle)); \
					rw_enter(&(lle)->lle_lock, RW_READER); \
				} while (0)
#define	LLE_WUNLOCK(lle)	do { \
					LLE_LOCK_TRACE(WU, (lle)); \
					rw_exit(&(lle)->lle_lock); \
				} while (0)
#define	LLE_RUNLOCK(lle)	do { \
					LLE_LOCK_TRACE(RU, (lle)); \
					rw_exit(&(lle)->lle_lock); \
				} while (0)
#define	LLE_DOWNGRADE(lle)	rw_downgrade(&(lle)->lle_lock)
#define	LLE_TRY_UPGRADE(lle)	rw_tryupgrade(&(lle)->lle_lock)
#ifdef __FreeBSD__
#define	LLE_LOCK_INIT(lle)	rw_init_flags(&(lle)->lle_lock, "lle", RW_DUPOK)
#else /* XXX */
#define	LLE_LOCK_INIT(lle)	rw_init(&(lle)->lle_lock)
#endif
#define	LLE_LOCK_DESTROY(lle)	rw_destroy(&(lle)->lle_lock)
#define	LLE_WLOCK_ASSERT(lle)	KASSERT(rw_write_held(&(lle)->lle_lock))

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

#if 0
#define LLE_REF_TRACE(t, lle, n) \
	log(LOG_DEBUG, "%s:%d: %p REF(" #t "): refcnt=%d\n", \
	    __func__, __LINE__, (lle), (n))
#else
#define LLE_REF_TRACE(t, lle, n)	do {} while (0)
#endif

#define	LLE_ADDREF(lle) do {					\
	LLE_WLOCK_ASSERT(lle);					\
	LLE_REF_TRACE(ADD, (lle), (lle)->lle_refcnt);		\
	KASSERTMSG((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);					\
	LLE_REF_TRACE(REM, (lle), (lle)->lle_refcnt);		\
	KASSERTMSG((lle)->lle_refcnt > 0,			\
	    "bogus refcnt %d on lle %p",			\
	    (lle)->lle_refcnt, (lle));				\
	(lle)->lle_refcnt--;					\
	if ((lle)->lle_refcnt == 0)				\
		LLE_REF_TRACE(ZERO, (lle), (lle)->lle_refcnt);	\
} while (0)

#define	LLE_FREE_LOCKED(lle) do {				\
	if ((lle)->lle_refcnt == 1) {				\
		if ((lle)->lle_ll_free != NULL)			\
			(lle)->lle_ll_free(lle);		\
		(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_create_t)(struct lltable *, u_int flags,
    const struct sockaddr *l3addr, const struct rtentry *);
typedef	int (llt_delete_t)(struct lltable *, u_int flags,
    const struct sockaddr *l3addr);
typedef void (llt_prefix_free_t)(struct lltable *,
    const struct sockaddr *prefix, const struct sockaddr *mask, u_int flags);
typedef int (llt_dump_entry_t)(struct lltable *, struct llentry *,
    struct rt_walkarg *);
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 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;
	unsigned int		llt_lle_count;
	struct ifnet		*llt_ifp;

	llt_lookup_t		*llt_lookup;
	llt_create_t		*llt_create;
	llt_delete_t		*llt_delete;
	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;
};

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_PUB		0x0020	/* publish entry ??? */
#define	LLE_LINKED	0x0040	/* linked to lookup structure */
/* LLE request flags */
#define	LLE_EXCLUSIVE	0x2000	/* return lle xlocked  */

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

void lltableinit(void);

struct lltable *lltable_allocate_htbl(uint32_t hsize);
void		lltable_free(struct lltable *);
void		lltable_link(struct lltable *llt);
void		lltable_prefix_free(const int, const struct sockaddr *,
		    const struct sockaddr *, const u_int);
void		lltable_drain(int);
void		lltable_purge_entries(struct lltable *);
int		lltable_sysctl_dump(int, struct rt_walkarg *);
int		lltable_dump_entry(struct lltable *, struct llentry *,
		    struct rt_walkarg *, struct sockaddr *);

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

struct llentry  *llentry_pool_get(int);
void		llentry_pool_put(struct llentry *);

/* helper functions */
size_t lltable_drop_entry_queue(struct llentry *);

struct llentry *lltable_create_lle(struct lltable *llt, u_int flags,
    const void *paddr);
void lltable_link_entry(struct lltable *llt, struct llentry *lle);
void lltable_unlink_entry(struct lltable *llt, struct llentry *lle);
void lltable_free_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);

static __inline unsigned int
lltable_get_entry_count(struct lltable *llt)
{
	return llt->llt_lle_count;
}

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));
}

static __inline struct llentry *
lla_create(struct lltable *llt, u_int flags, const struct sockaddr *l3addr,
    const struct rtentry *rt)
{

	return (llt->llt_create(llt, flags, l3addr, rt));
}

static __inline int
lla_delete(struct lltable *llt, u_int flags, const struct sockaddr *l3addr)
{

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


int lla_rt_output(const u_char, const int, const time_t,
    struct rt_addrinfo *info, int);

#endif  /* _NET_IF_LLATBL_H_ */