/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1986, 1991, 1993
 *      The Regents of the University of California.  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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 THE REGENTS 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.
 */
/************************************************************************
 * Note: In this file a 'fib' is a "forwarding information base"        *
 * Which is the new name for an in kernel routing (next hop) table.     *
 ***********************************************************************/

#include "opt_route.h"

#include <sys/param.h>
#include <sys/eventhandler.h>
#include <sys/socket.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/jail.h>
#include <sys/osd.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/sx.h>
#include <sys/domain.h>
#include <sys/sysproto.h>

#include <net/vnet.h>
#include <net/route.h>
#include <net/route/route_ctl.h>
#include <net/route/route_var.h>

/* Kernel config default option. */
#ifdef ROUTETABLES
#if ROUTETABLES <= 0
#error "ROUTETABLES defined too low"
#endif
#if ROUTETABLES > RT_MAXFIBS
#error "ROUTETABLES defined too big"
#endif
#define RT_NUMFIBS      ROUTETABLES
#endif /* ROUTETABLES */
/* Initialize to default if not otherwise set. */
#ifndef RT_NUMFIBS
#define RT_NUMFIBS      1
#endif

static void grow_rtables(uint32_t num_fibs);

VNET_DEFINE_STATIC(struct sx, rtables_lock);
#define V_rtables_lock          VNET(rtables_lock)
#define RTABLES_LOCK()          sx_xlock(&V_rtables_lock)
#define RTABLES_UNLOCK()        sx_xunlock(&V_rtables_lock)
#define RTABLES_LOCK_INIT()     sx_init(&V_rtables_lock, "rtables lock")
#define RTABLES_LOCK_ASSERT()   sx_assert(&V_rtables_lock, SA_LOCKED)

VNET_DEFINE_STATIC(struct rib_head **, rt_tables);
#define V_rt_tables     VNET(rt_tables)

VNET_DEFINE(uint32_t, _rt_numfibs) = RT_NUMFIBS;

/*
 * Handler for net.my_fibnum.
 * Returns current fib of the process.
 */
static int
sysctl_my_fibnum(SYSCTL_HANDLER_ARGS)
{
        int fibnum;
        int error;

        fibnum = curthread->td_proc->p_fibnum;
        error = sysctl_handle_int(oidp, &fibnum, 0, req);
        return (error);
}
SYSCTL_PROC(_net, OID_AUTO, my_fibnum,
    CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
    &sysctl_my_fibnum, "I",
    "default FIB of caller");

static uint32_t
normalize_num_rtables(uint32_t num_rtables)
{

        if (num_rtables > RT_MAXFIBS)
                num_rtables = RT_MAXFIBS;
        else if (num_rtables == 0)
                num_rtables = 1;
        return (num_rtables);
}

/*
 * Sets the number of fibs in the current vnet.
 * Function does not allow shrinking number of rtables.
 */
static int
sysctl_fibs(SYSCTL_HANDLER_ARGS)
{
        uint32_t new_fibs;
        int error;

        RTABLES_LOCK();
        new_fibs = V_rt_numfibs;
        error = sysctl_handle_32(oidp, &new_fibs, 0, req);
        if (error == 0) {
                new_fibs = normalize_num_rtables(new_fibs);

                if (new_fibs < V_rt_numfibs)
                        error = ENOTCAPABLE;
                if (new_fibs > V_rt_numfibs)
                        grow_rtables(new_fibs);
        }
        RTABLES_UNLOCK();

        return (error);
}
SYSCTL_PROC(_net, OID_AUTO, fibs,
    CTLFLAG_VNET | CTLTYPE_U32 | CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE,
    NULL, 0, &sysctl_fibs, "IU",
    "set number of fibs");

/*
 * Sets fib of a current process.
 */
int
sys_setfib(struct thread *td, struct setfib_args *uap)
{
        int error = 0;

        CURVNET_SET(TD_TO_VNET(td));
        if (uap->fibnum >= 0 && uap->fibnum < V_rt_numfibs)
                td->td_proc->p_fibnum = uap->fibnum;
        else
                error = EINVAL;
        CURVNET_RESTORE();

        return (error);
}

static int
rtables_check_proc_fib(void *obj, void *data)
{
        struct prison *pr = obj;
        struct thread *td = data;
        int error = 0;

        if (TD_TO_VNET(td) != pr->pr_vnet) {
                /* number of fibs may be lower in a new vnet */
                CURVNET_SET(pr->pr_vnet);
                if (td->td_proc->p_fibnum >= V_rt_numfibs)
                        error = EINVAL;
                CURVNET_RESTORE();
        }
        return (error);
}

static void
rtables_prison_destructor(void *data)
{
}

static void
rtables_init(void *dummy __unused)
{
        osd_method_t methods[PR_MAXMETHOD] = {
            [PR_METHOD_ATTACH] =        rtables_check_proc_fib,
        };
        osd_jail_register(rtables_prison_destructor, methods);
}
SYSINIT(rtables_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, rtables_init, NULL);


/*
 * If required, copy interface routes from existing tables to the
 * newly-created routing table.
 */
static void
populate_kernel_routes(struct rib_head **new_rt_tables, struct rib_head *rh)
{
        for (int i = 0; i < V_rt_numfibs; i++) {
                struct rib_head *rh_src = new_rt_tables[i * (AF_MAX + 1) + rh->rib_family];
                if ((rh_src != NULL) && (rh_src != rh))
                        rib_copy_kernel_routes(rh_src, rh);
        }
}

/*
 * Grows up the number of routing tables in the current fib.
 * Function creates new index array for all rtables and allocates
 *  remaining routing tables.
 */
static void
grow_rtables(uint32_t num_tables)
{
        struct domain *dom;
        struct rib_head **prnh, *rh;
        struct rib_head **new_rt_tables, **old_rt_tables;
        int family;

        RTABLES_LOCK_ASSERT();

        KASSERT(num_tables >= V_rt_numfibs, ("num_tables(%u) < rt_numfibs(%u)\n",
                                num_tables, V_rt_numfibs));

        new_rt_tables = mallocarray(num_tables * (AF_MAX + 1), sizeof(void *),
            M_RTABLE, M_WAITOK | M_ZERO);

#ifdef FIB_ALGO
        fib_grow_rtables(num_tables);
#endif

        /*
         * Current rt_tables layout:
         * fib0[af0, af1, af2, .., AF_MAX]fib1[af0, af1, af2, .., Af_MAX]..
         * this allows to copy existing tables data by using memcpy()
         */
        if (V_rt_tables != NULL)
                memcpy(new_rt_tables, V_rt_tables,
                    V_rt_numfibs * (AF_MAX + 1) * sizeof(void *));

        /* Populate the remainders */
        SLIST_FOREACH(dom, &domains, dom_next) {
                if (dom->dom_rtattach == NULL)
                        continue;
                family = dom->dom_family;
                for (int i = 0; i < num_tables; i++) {
                        prnh = &new_rt_tables[i * (AF_MAX + 1) + family];
                        if (*prnh != NULL)
                                continue;
                        rh = dom->dom_rtattach(i);
                        populate_kernel_routes(new_rt_tables, rh);
                        *prnh = rh;
                }
        }

        /*
         * Update rtables pointer.
         * Ensure all writes to new_rt_tables has been completed before
         *  switching pointer.
         */
        atomic_thread_fence_rel();
        old_rt_tables = V_rt_tables;
        V_rt_tables = new_rt_tables;

        EVENTHANDLER_INVOKE(rtnumfibs_change, num_tables);

        /* Wait till all cpus see new pointers */
        atomic_thread_fence_rel();
        NET_EPOCH_WAIT();

        /* Set number of fibs to a new value */
        V_rt_numfibs = num_tables;

#ifdef FIB_ALGO
        /* Attach fib algo to the new rtables */
        SLIST_FOREACH(dom, &domains, dom_next) {
                if (dom->dom_rtattach != NULL)
                        fib_setup_family(dom->dom_family, num_tables);
        }
#endif

        if (old_rt_tables != NULL)
                free(old_rt_tables, M_RTABLE);
}

static void
vnet_rtables_init(const void *unused __unused)
{
        int num_rtables_base;

        if (IS_DEFAULT_VNET(curvnet)) {
                num_rtables_base = RT_NUMFIBS;
                TUNABLE_INT_FETCH("net.fibs", &num_rtables_base);
                V_rt_numfibs = normalize_num_rtables(num_rtables_base);
        } else
                V_rt_numfibs = 1;

        vnet_rtzone_init();
#ifdef FIB_ALGO
        vnet_fib_init();
#endif
        RTABLES_LOCK_INIT();

        RTABLES_LOCK();
        grow_rtables(V_rt_numfibs);
        RTABLES_UNLOCK();
}
VNET_SYSINIT(vnet_rtables_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH,
    vnet_rtables_init, NULL);

#ifdef VIMAGE
static void
rtables_destroy(const void *unused __unused)
{
        struct rib_head *rnh;
        struct domain *dom;
        int family;

        RTABLES_LOCK();
        SLIST_FOREACH(dom, &domains, dom_next) {
                if (dom->dom_rtdetach == NULL)
                        continue;
                family = dom->dom_family;
                for (int i = 0; i < V_rt_numfibs; i++) {
                        rnh = rt_tables_get_rnh(i, family);
                        dom->dom_rtdetach(rnh);
                }
        }
        RTABLES_UNLOCK();

        /*
         * dom_rtdetach calls rt_table_destroy(), which
         *  schedules deletion for all rtentries, nexthops and control
         *  structures. Wait for the destruction callbacks to fire.
         * Note that this should result in freeing all rtentries, but
         *  nexthops deletions will be scheduled for the next epoch run
         *  and will be completed after vnet teardown.
         */
        NET_EPOCH_DRAIN_CALLBACKS();

        free(V_rt_tables, M_RTABLE);
        vnet_rtzone_destroy();
#ifdef FIB_ALGO
        vnet_fib_destroy();
#endif
}
VNET_SYSUNINIT(rtables_destroy, SI_SUB_PROTO_DOMAIN, SI_ORDER_FIRST,
    rtables_destroy, NULL);
#endif

static inline struct rib_head *
rt_tables_get_rnh_ptr(uint32_t table, sa_family_t family)
{
        struct rib_head **prnh;

        KASSERT(table < V_rt_numfibs,
            ("%s: table out of bounds (%d < %d)", __func__, table,
             V_rt_numfibs));
        KASSERT(family < (AF_MAX + 1),
            ("%s: fam out of bounds (%d < %d)", __func__, family, AF_MAX + 1));

        /* rnh is [fib=0][af=0]. */
        prnh = V_rt_tables;
        /* Get the offset to the requested table and fam. */
        prnh += table * (AF_MAX + 1) + family;

        return (*prnh);
}

struct rib_head *
rt_tables_get_rnh(uint32_t table, sa_family_t family)
{

        return (rt_tables_get_rnh_ptr(table, family));
}

struct rib_head *
rt_tables_get_rnh_safe(uint32_t table, sa_family_t family)
{
        if (__predict_false(table >= V_rt_numfibs))
                return (NULL);
        if (__predict_false(family >= (AF_MAX + 1)))
                return (NULL);
        return (rt_tables_get_rnh_ptr(table, family));
}

u_int
rt_tables_get_gen(uint32_t table, sa_family_t family)
{
        struct rib_head *rnh;

        rnh = rt_tables_get_rnh_ptr(table, family);
        KASSERT(rnh != NULL, ("%s: NULL rib_head pointer table %d family %d",
            __func__, table, family));
        return (rnh->rnh_gen);
}