/*      $NetBSD: nd.h,v 1.4 2026/03/24 21:32:17 christos Exp $  */

/*
 * Copyright (c) 2020 The NetBSD Foundation, Inc.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Roy Marples.
 *
 * 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 THE AUTHOR ``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 THE AUTHOR 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.
 */

#ifndef _NET_ND_H_
#define _NET_ND_H_

/* ND LLINFO states */
#define ND_LLINFO_PURGE         -3
#define ND_LLINFO_NOSTATE       -2
#define ND_LLINFO_WAITDELETE    -1
#define ND_LLINFO_INCOMPLETE    0
#define ND_LLINFO_REACHABLE     1
#define ND_LLINFO_STALE         2
#define ND_LLINFO_DELAY         3
#define ND_LLINFO_PROBE         4
#define ND_LLINFO_UNREACHABLE   5

#ifdef _KERNEL
#define ND_IS_LLINFO_PROBREACH(ln)      \
        ((ln)->ln_state > ND_LLINFO_INCOMPLETE)
#define ND_IS_LLINFO_PERMANENT(ln)      \
        (((ln)->ln_expire == 0) && ((ln)->ln_state > ND_LLINFO_INCOMPLETE))

/* ND timer types */
#define ND_TIMER_IMMEDIATE              0
#define ND_TIMER_TICK                   1
#define ND_TIMER_REACHABLE              2
#define ND_TIMER_RETRANS                3
#define ND_TIMER_RETRANS_BACKOFF        4
#define ND_TIMER_EXPIRE                 5
#define ND_TIMER_DELAY                  6
#define ND_TIMER_GC                     7

/* node constants */
#define MAX_REACHABLE_TIME              3600000 /* msec */
#define REACHABLE_TIME                  30000   /* msec */
#define RETRANS_TIMER                   1000    /* msec */
#define MAX_RETRANS_TIMER               60000   /* msec */
#define BACKOFF_MULTIPLE                3
#define MIN_RANDOM_FACTOR               512     /* 1024 * 0.5 */
#define MAX_RANDOM_FACTOR               1536    /* 1024 * 1.5 */
#define ND_COMPUTE_RTIME(x) \
                ((MIN_RANDOM_FACTOR * (x >> 10)) + (cprng_fast32() & \
                ((MAX_RANDOM_FACTOR - MIN_RANDOM_FACTOR) * (x >> 10))))

struct nd_domain {
        int nd_family;
        int nd_delay;           /* delay first probe time in seconds */
        int nd_mmaxtries;       /* maximum multicast query */
        int nd_umaxtries;       /* maximum unicast query */
        int nd_retransmultiple; /* retransmission multiplier for backoff */
        int nd_maxretrans;      /* maximum retransmission time in msec */
        int nd_maxnudhint;      /* max # of subsequent upper layer hints */
        int nd_maxqueuelen;     /* max # of packets in unresolved ND entries */
        int nd_gctimer;         /* stale neighbor GC timer duration */
        bool (*nd_nud_enabled)(struct ifnet *);
        unsigned int (*nd_reachable)(struct ifnet *);   /* msec */
        unsigned int (*nd_retrans)(struct ifnet *);     /* msec */
        union l3addr *(*nd_holdsrc)(struct llentry *, union l3addr *);
        void (*nd_output)(struct ifnet *, const union l3addr *,
            const union l3addr *, const uint8_t *, const union l3addr *);
        void (*nd_missed)(struct ifnet *, const union l3addr *,
            int16_t, struct mbuf *);
        void (*nd_free)(struct llentry *, int);
};

int nd_resolve(struct llentry *, const struct rtentry *, struct mbuf *,
    uint8_t *, size_t);
void nd_set_timer(struct llentry *, int);
void nd_nud_hint(struct llentry *);

void nd_attach_domain(struct nd_domain *);
#endif /* !_KERNEL */
#endif /* !_NET_ND_H_ */