/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2006 Shteryana Shopova <syrinx@FreeBSD.org>
 * 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 THE 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 THE 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.
 *
 * Bridge MIB implementation for SNMPd.
 */

#include <sys/param.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/types.h>

#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_mib.h>
#include <net/if_types.h>

#include <errno.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>

#include <bsnmp/snmpmod.h>
#include <bsnmp/snmp_mibII.h>

#define SNMPTREE_TYPES
#include "bridge_tree.h"
#include "bridge_snmp.h"
#include "bridge_oid.h"

static struct lmodule *bridge_module;

/* For the registration. */
static const struct asn_oid oid_dot1Bridge = OIDX_dot1dBridge;
/* The registration. */
static uint reg_bridge;

/* Periodic timer for polling all bridges' data. */
static void *bridge_data_timer;
static void *bridge_tc_timer;

static int bridge_data_maxage = SNMP_BRIDGE_DATA_MAXAGE;
static int bridge_poll_ticks = SNMP_BRIDGE_POLL_INTERVAL * 100;
static int bridge_tc_poll_ticks = SNMP_BRIDGE_TC_POLL_INTERVAL * 100;

/*
 * Our default bridge, whose info will be visible under
 * the dot1dBridge subtree and functions to set/fetch it.
 */
static char bif_default_name[IFNAMSIZ] = "bridge0";
static struct bridge_if *bif_default;

struct bridge_if *
bridge_get_default(void)
{
        struct mibif *ifp;

        if (bif_default != NULL) {

                /* Walk through the mibII interface list. */
                for (ifp = mib_first_if(); ifp != NULL; ifp = mib_next_if(ifp))
                        if (strcmp(ifp->name, bif_default->bif_name) == 0)
                                break;

                if (ifp == NULL)
                        bif_default = NULL;
        }

        return (bif_default);
}

void
bridge_set_default(struct bridge_if *bif)
{
        bif_default = bif;

        syslog(LOG_ERR, "Set default bridge interface to: %s",
            bif == NULL ? "(none)" : bif->bif_name);
}

const char *
bridge_get_default_name(void)
{
        return (bif_default_name);
}

static int
bridge_set_default_name(const char *bif_name, uint len)
{
        struct bridge_if *bif;

        if (len >= IFNAMSIZ)
                return (-1);

        bcopy(bif_name, bif_default_name, len);
        bif_default_name[len] = '\0';

        if ((bif = bridge_if_find_ifname(bif_default_name)) == NULL) {
                bif_default = NULL;
                return (0);
        }

        bif_default = bif;
        return (1);
}

int
bridge_get_data_maxage(void)
{
        return (bridge_data_maxage);
}

static void
bridge_set_poll_ticks(int poll_ticks)
{
        if (bridge_data_timer != NULL)
                timer_stop(bridge_data_timer);

        bridge_poll_ticks = poll_ticks;
        bridge_data_timer = timer_start_repeat(bridge_poll_ticks,
            bridge_poll_ticks, bridge_update_all, NULL, bridge_module);
}
/*
 * The bridge module configuration via SNMP.
 */
static int
bridge_default_name_save(struct snmp_context *ctx, const char *bridge_default)
{
        if ((ctx->scratch->int1 = strlen(bridge_default)) >= IFNAMSIZ)
                return (-1);

        if ((ctx->scratch->ptr1 = malloc(IFNAMSIZ)) == NULL)
                return (-1);

        strncpy(ctx->scratch->ptr1, bridge_default, ctx->scratch->int1);
        return (0);
}

int
op_begemot_bridge_config(struct snmp_context *ctx, struct snmp_value *val,
    uint sub, uint iidx __unused, enum snmp_op op)
{
        switch (op) {
            case SNMP_OP_GET:
                switch (val->var.subs[sub - 1]) {
                    case LEAF_begemotBridgeDefaultBridgeIf:
                        return (string_get(val, bridge_get_default_name(), -1));

                    case LEAF_begemotBridgeDataUpdate:
                        val->v.integer = bridge_data_maxage;
                        return (SNMP_ERR_NOERROR);

                    case LEAF_begemotBridgeDataPoll:
                        val->v.integer = bridge_poll_ticks / 100;
                        return (SNMP_ERR_NOERROR);
                }
                abort();

            case SNMP_OP_GETNEXT:
                abort();

            case SNMP_OP_SET:
                switch (val->var.subs[sub - 1]) {
                    case LEAF_begemotBridgeDefaultBridgeIf:
                        /*
                         * Cannot use string_save() here - requires either
                         * a fixed-sized or var-length string - not less
                         * than or equal.
                         */
                        if (bridge_default_name_save(ctx,
                            bridge_get_default_name()) < 0)
                                return (SNMP_ERR_RES_UNAVAIL);

                        if (bridge_set_default_name(val->v.octetstring.octets,
                            val->v.octetstring.len) < 0)
                                return (SNMP_ERR_BADVALUE);
                        return (SNMP_ERR_NOERROR);

                    case LEAF_begemotBridgeDataUpdate:
                        if (val->v.integer < SNMP_BRIDGE_DATA_MAXAGE_MIN ||
                            val->v.integer > SNMP_BRIDGE_DATA_MAXAGE_MAX)
                                return (SNMP_ERR_WRONG_VALUE);
                        ctx->scratch->int1 = bridge_data_maxage;
                        bridge_data_maxage = val->v.integer;
                        return (SNMP_ERR_NOERROR);

                    case LEAF_begemotBridgeDataPoll:
                        if (val->v.integer < SNMP_BRIDGE_POLL_INTERVAL_MIN ||
                            val->v.integer > SNMP_BRIDGE_POLL_INTERVAL_MAX)
                                return (SNMP_ERR_WRONG_VALUE);
                        ctx->scratch->int1 = val->v.integer;
                        return (SNMP_ERR_NOERROR);
                }
                abort();

            case SNMP_OP_ROLLBACK:
                switch (val->var.subs[sub - 1]) {
                    case LEAF_begemotBridgeDefaultBridgeIf:
                        bridge_set_default_name(ctx->scratch->ptr1,
                            ctx->scratch->int1);
                        free(ctx->scratch->ptr1);
                        break;
                    case LEAF_begemotBridgeDataUpdate:
                        bridge_data_maxage = ctx->scratch->int1;
                        break;
                }
                return (SNMP_ERR_NOERROR);

            case SNMP_OP_COMMIT:
                switch (val->var.subs[sub - 1]) {
                    case LEAF_begemotBridgeDefaultBridgeIf:
                        free(ctx->scratch->ptr1);
                        break;
                    case LEAF_begemotBridgeDataPoll:
                        bridge_set_poll_ticks(ctx->scratch->int1 * 100);
                        break;
                }
                return (SNMP_ERR_NOERROR);
        }

        abort();
}

/*
 * Bridge mib module initialization hook.
 * Returns 0 on success, < 0 on error.
 */
static int
bridge_init(struct lmodule * mod, int argc __unused, char *argv[] __unused)
{
        bridge_module = mod;

        if (bridge_kmod_load() < 0)
                return (-1);

        if (bridge_ioctl_init() < 0)
                return (-1);

        /* Register to get creation messages for bridge interfaces. */
        if (mib_register_newif(bridge_attach_newif, bridge_module)) {
                syslog(LOG_ERR, "Cannot register newif function: %s",
                    strerror(errno));
                return (-1);
        }

        return (0);
}

/*
 * Bridge mib module finalization hook.
 */
static int
bridge_fini(void)
{
        mib_unregister_newif(bridge_module);
        or_unregister(reg_bridge);

        if (bridge_data_timer != NULL) {
                timer_stop(bridge_data_timer);
                bridge_data_timer = NULL;
        }

        if (bridge_tc_timer != NULL) {
                timer_stop(bridge_tc_timer);
                bridge_tc_timer = NULL;
        }

        bridge_ifs_fini();
        bridge_ports_fini();
        bridge_addrs_fini();

        return (0);
}

/*
 * Bridge mib module start operation.
 */
static void
bridge_start(void)
{
        reg_bridge = or_register(&oid_dot1Bridge,
            "The IETF MIB for Bridges (RFC 4188).", bridge_module);

        bridge_data_timer = timer_start_repeat(bridge_poll_ticks,
            bridge_poll_ticks, bridge_update_all, NULL, bridge_module);

        bridge_tc_timer = timer_start_repeat(bridge_tc_poll_ticks,
            bridge_tc_poll_ticks, bridge_update_tc_time, NULL, bridge_module);
}

static void
bridge_dump(void)
{
        struct bridge_if *bif;

        if ((bif = bridge_get_default()) == NULL)
                syslog(LOG_ERR, "Dump: no default bridge interface");
        else
                syslog(LOG_ERR, "Dump: default bridge interface %s",
                     bif->bif_name);

        bridge_ifs_dump();
        bridge_pf_dump();
}

const struct snmp_module config = {
        .comment = "This module implements the bridge mib (RFC 4188).",
        .init =         bridge_init,
        .fini =         bridge_fini,
        .start =        bridge_start,
        .tree =         bridge_ctree,
        .dump =         bridge_dump,
        .tree_size =    bridge_CTREE_SIZE,
};