/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * 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>
#ifndef _NET_IF_LLATBL_H_
#define _NET_IF_LLATBL_H_

#include <sys/_eventhandler.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                 r_family;       /* Upper layer proto family */
        uint8_t                 spare0[2];
        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_SLIST_HEAD(llentry_children_head,llentry)    lle_children;   /* child encaps */
        CK_SLIST_ENTRY(llentry) lle_child_next; /* child encaps */
        struct llentry          *lle_parent;    /* parent for a child */

        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_SF(_fam, _flags)    (((_flags) & 0xFFFF) | ((_fam) << 16))

#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 int (llt_link_entry_t)(struct lltable *, struct llentry *);
typedef int (llt_unlink_entry_t)(struct llentry *);
typedef void (llt_mark_used_t)(struct llentry *);
typedef void (llt_post_resolved_t)(struct lltable *, 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 *);
typedef bool (llt_match_cb_t)(struct lltable *, struct llentry *, void *);

struct lltable {
        SLIST_ENTRY(lltable)    llt_link;
        sa_family_t             llt_af;
        uint8_t                 llt_flags;
        uint8_t                 llt_spare[2];
        int                     llt_hsize;
        int                     llt_entries;
        int                     llt_maxentries;
        struct llentries        *lle_head;
        struct ifnet            *llt_ifp;
        struct mtx              llt_lock;

        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;
        llt_post_resolved_t     *llt_post_resolved;
};

#define LLTABLE_LOCK(llt)       mtx_lock(&(llt)->llt_lock)
#define LLTABLE_UNLOCK(llt)     mtx_unlock(&(llt)->llt_lock)
#define LLTABLE_LOCK_ASSERT(llt)        mtx_assert(&(llt)->llt_lock, MA_OWNED)
#define LLTABLE_RLOCK_ASSERT(llt)       MPASS(in_epoch(net_epoch_preempt) || \
                                        mtx_owned(&(llt)->llt_lock))

MALLOC_DECLARE(M_LLTABLE);

/*
 * LLtable flags
 */
#define LLT_ADDEDPROXY  0x01    /* added a proxy llentry */

/*
 * 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 */
#define LLE_CHILD       0x0080  /* Child LLE storing different AF encap */
/* 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);
int             lltable_sysctl_dumparp(int, struct sysctl_req *);
size_t          lltable_append_entry_queue(struct llentry *,
                    struct mbuf *, size_t);

struct lltable *in_lltable_get(struct ifnet *ifp);
struct lltable *in6_lltable_get(struct ifnet *ifp);
struct lltable *lltable_get(struct ifnet *ifp, int family);

size_t          llentry_free(struct llentry *);

/* 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);
int lltable_link_entry(struct lltable *llt, struct llentry *lle);
int lltable_unlink_entry(struct lltable *llt, struct llentry *lle);
void lltable_link_child_entry(struct llentry *parent_lle, struct llentry *child_lle);
void lltable_unlink_child_entry(struct llentry *child_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);

bool lltable_trylock(struct llentry *lle);

int lltable_foreach_lle(struct lltable *llt, llt_foreach_cb_t *f,
    void *farg);
void lltable_delete_conditional(struct lltable *llt, llt_match_cb_t *func,
    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));
}

void llentry_request_feedback(struct llentry *lle);
void llentry_mark_used(struct llentry *lle);
time_t llentry_get_hittime(struct llentry *lle);
int llentry_get_upper_family(const struct llentry *lle, int default_family);

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

        if (__predict_true(lle->r_skip_req == 0))
                return;
        llentry_mark_used(lle);
}
struct llentry *llentry_lookup_family(struct llentry *lle, int family);

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

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_ */