/*      $NetBSD: nd.h,v 1.3 2020/09/15 10:05:36 roy 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 */
       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_ */