bacnet_stack/src/bacnet/basic/npdu/s_router.c

/**
 * @file
 * @brief Methods to send various BACnet Router Network Layer Messages.
 * @author Tom Brennan <tbrennan3@users.sourceforge.net>
 * @date 2010
 * @copyright SPDX-License-Identifier: MIT
 */
#include <stddef.h>
#include <stdint.h>
#include <errno.h>
#include <string.h>
#include "bacnet/bacdef.h"
#include "bacnet/bacdcode.h"
#include "bacnet/bacaddr.h"
#include "bacnet/npdu.h"
#include "bacnet/apdu.h"
#include "bacnet/bactext.h"
/* some demo stuff needed */
#include "bacnet/basic/tsm/tsm.h"
#include "bacnet/basic/binding/address.h"
#include "bacnet/basic/object/device.h"
#include "bacnet/datalink/datalink.h"
#include "bacnet/basic/sys/debug.h"
#include "bacnet/basic/services.h"

/** Function to encode and send any supported Network Layer Message.
 * The payload for the message is encoded from information in the iArgs[] array.
 * The contents of iArgs are are, per message type:
 * - NETWORK_MESSAGE_WHO_IS_ROUTER_TO_NETWORK: Single int for DNET requested
 * - NETWORK_MESSAGE_I_AM_ROUTER_TO_NETWORK: Array of DNET(s) to send,
 *      terminated with -1
 * - NETWORK_MESSAGE_REJECT_MESSAGE_TO_NETWORK: array of 2 ints,
 *      first is reason, second is DNET of interest
 * - NETWORK_MESSAGE_ROUTER_BUSY_TO_NETWORK: same as I-Am-Router msg
 * - NETWORK_MESSAGE_ROUTER_AVAILABLE_TO_NETWORK: same as I-Am-Router msg
 * - NETWORK_MESSAGE_INIT_RT_TABLE and NETWORK_MESSAGE_INIT_RT_TABLE_ACK:
 *      Array of DNET(s) to process as "Ports", terminated with -1.  Each DNET
 *      will be expanded to a BACNET_ROUTER_PORT (with simple defaults for
 *      most fields) and encoded.
 *
 * @param network_message_type [in] The type of message to be sent.
 * @param dst [in/out] If not NULL, contains the destination for the message.
 * @param iArgs [in] An optional array of values whose meaning depends on
 *                   the type of message.
 * @return Number of bytes sent, or <=0 if no message was sent.
 */
int Send_Network_Layer_Message(
    BACNET_NETWORK_MESSAGE_TYPE network_message_type,
    BACNET_ADDRESS *dst,
    const int *iArgs)
{
    int len = 0;
    int pdu_len = 0;
    int bytes_sent = 0;
    const int *pVal = iArgs; /* Start with first value */
    bool data_expecting_reply = false;
    BACNET_NPDU_DATA npdu_data;
    BACNET_ADDRESS bcastDest;

    if (iArgs == NULL) {
        return 0; /* Can't do anything here */
    }

    /* If dst was NULL, get our (local net) broadcast MAC address. */
    if (dst == NULL) {
        datalink_get_broadcast_address(&bcastDest);
        dst = &bcastDest;
    }

    if (network_message_type == NETWORK_MESSAGE_INIT_RT_TABLE) {
        data_expecting_reply = true; /* DER in this one case */
    }
    npdu_encode_npdu_network(
        &npdu_data, network_message_type, data_expecting_reply,
        MESSAGE_PRIORITY_NORMAL);

    /* We don't need src information, since a message can't originate from
     * our downstream BACnet network.
     */
    pdu_len =
        npdu_encode_pdu(&Handler_Transmit_Buffer[0], dst, NULL, &npdu_data);

    /* Now encode the optional payload bytes, per message type */
    switch (network_message_type) {
        case NETWORK_MESSAGE_WHO_IS_ROUTER_TO_NETWORK:
            if (*pVal >= 0) {
                len = encode_unsigned16(
                    &Handler_Transmit_Buffer[pdu_len], (uint16_t)*pVal);
                pdu_len += len;
            }
            /* else, don't encode a DNET */
            break;

        case NETWORK_MESSAGE_I_AM_ROUTER_TO_NETWORK:
        case NETWORK_MESSAGE_ROUTER_BUSY_TO_NETWORK:
        case NETWORK_MESSAGE_ROUTER_AVAILABLE_TO_NETWORK:
            while (*pVal >= 0) {
                len = encode_unsigned16(
                    &Handler_Transmit_Buffer[pdu_len], (uint16_t)*pVal);
                pdu_len += len;
                pVal++;
            }
            break;

        case NETWORK_MESSAGE_NETWORK_NUMBER_IS:
            /* Encode the DNET */
            len = encode_unsigned16(
                &Handler_Transmit_Buffer[pdu_len], (uint16_t)*pVal);
            pdu_len += len;
            pVal++;
            /* Encode the Status byte */
            Handler_Transmit_Buffer[pdu_len] = (uint8_t)*pVal;
            pdu_len++;
            pVal++;
            break;

        case NETWORK_MESSAGE_REJECT_MESSAGE_TO_NETWORK:
            /* Encode the Reason byte, then the DNET */
            Handler_Transmit_Buffer[pdu_len++] = (uint8_t)*pVal;
            pVal++;
            len = encode_unsigned16(
                &Handler_Transmit_Buffer[pdu_len], (uint16_t)*pVal);
            pdu_len += len;
            break;

        case NETWORK_MESSAGE_INIT_RT_TABLE:
        case NETWORK_MESSAGE_INIT_RT_TABLE_ACK:
            /* First, count the number of Ports we will encode */
            len = 0; /* Re-purpose len as our counter here */
            while (*pVal >= 0) {
                len++;
                pVal++;
            }
            Handler_Transmit_Buffer[pdu_len++] = (uint8_t)len;

            if (len > 0) {
                uint8_t portID = 1;
                pVal = iArgs; /* Reset to beginning */
                /* Now encode each (virtual) BACNET_ROUTER_PORT.
                 * We will simply use a positive index for PortID,
                 * and have no PortInfo.
                 */
                while (*pVal >= 0) {
                    len = encode_unsigned16(
                        &Handler_Transmit_Buffer[pdu_len], (uint16_t)*pVal);
                    pdu_len += len;
                    Handler_Transmit_Buffer[pdu_len++] = portID++;
                    Handler_Transmit_Buffer[pdu_len++] = 0;
                    debug_printf(
                        "  Sending Routing Table entry for %u \n", *pVal);
                    pVal++;
                }
            }
            break;

        default:
            debug_printf(
                "Not sent: %s message unsupported \n",
                bactext_network_layer_msg_name(network_message_type));
            return 0;
    }

    if (dst != NULL) {
        debug_printf(
            "Sending %s message to BACnet network %u \n",
            bactext_network_layer_msg_name(network_message_type), dst->net);
    } else {
        debug_printf(
            "Sending %s message to local BACnet network \n",
            bactext_network_layer_msg_name(network_message_type));
    }

    /* Now send the message */
    bytes_sent = datalink_send_pdu(
        dst, &npdu_data, &Handler_Transmit_Buffer[0], pdu_len);
#if PRINT_ENABLED
    if (bytes_sent <= 0) {
        int wasErrno = errno; /* preserve the errno */
        debug_printf(
            "Failed to send %s message (%s)!\n",
            bactext_network_layer_msg_name(network_message_type),
            strerror(wasErrno));
    }
#endif
    return bytes_sent;
}

/** Finds a specific router, or all reachable BACnet networks.
 * The response(s) will come in I-am-router-to-network message(s).
 * @ingroup NMRC
 *
 * @param dst [in] If NULL, request will be broadcast to the local BACnet
 *                 network.  Optionally may designate a particular router
 *                 destination to respond.
 * @param dnet [in] Which BACnet network to request for; if -1, no DNET
 *                 will be sent and the receiving router(s) will send
 *                 their full list of reachable BACnet networks.
 */
void Send_Who_Is_Router_To_Network(BACNET_ADDRESS *dst, int dnet)
{
    Send_Network_Layer_Message(
        NETWORK_MESSAGE_WHO_IS_ROUTER_TO_NETWORK, dst, &dnet);
}

/** Broadcast an I-am-router-to-network message, giving the list of networks
 * we can reach.
 * The message will be sent to our normal DataLink Layer interface,
 * not the routed backend.
 * @ingroup NMRC
 *
 * @param DNET_list [in] List of BACnet network numbers for which I am a router,
 *                       terminated with -1
 */
void Send_I_Am_Router_To_Network(const int DNET_list[])
{
    /* Use a NULL dst here since we want a broadcast MAC address. */
    Send_Network_Layer_Message(
        NETWORK_MESSAGE_I_AM_ROUTER_TO_NETWORK, NULL, DNET_list);
}

/** Finds a specific router, or all reachable BACnet networks.
 * The response(s) will come in I-am-router-to-network message(s).
 * @ingroup NMRC
 *
 * @param dst [in] If NULL, request will be broadcast to the local BACnet
 *                 network.  Otherwise, designates a particular router
 *                 destination.
 * @param reject_reason [in] One of the BACNET_NETWORK_REJECT_REASONS codes.
 * @param dnet [in] Which BACnet network originated the message.
 */
void Send_Reject_Message_To_Network(
    BACNET_ADDRESS *dst, uint8_t reject_reason, int dnet)
{
    int iArgs[2];
    iArgs[0] = reject_reason;
    iArgs[1] = dnet;
    Send_Network_Layer_Message(
        NETWORK_MESSAGE_REJECT_MESSAGE_TO_NETWORK, dst, iArgs);
    debug_printf("  Reject Reason=%d, DNET=%u\n", reject_reason, dnet);
}

/** Send an Initialize Routing Table message, built from an optional DNET[]
 * array.
 * There are two cases here:
 * 1) We are requesting a destination router's Routing Table.
 *    In that case, DNET[] should just have one entry of -1 (no routing table
 *    is sent).
 * 2) We are sending out our Routing Table for some reason (normally bcast it).
 * @ingroup NMRC
 *
 * @param dst [in] If NULL, msg will be broadcast to the local BACnet network.
 *                 Optionally may designate a particular router destination,
 *                 especially when requesting a Routing Table.
 * @param DNET_list [in] List of BACnet network numbers for which I am a router,
 *                       terminated with -1.  Will be just -1 when we are
 *                       requesting a routing table.
 */
void Send_Initialize_Routing_Table(BACNET_ADDRESS *dst, const int DNET_list[])
{
    /* Use a NULL dst here since we want a broadcast MAC address. */
    Send_Network_Layer_Message(NETWORK_MESSAGE_INIT_RT_TABLE, dst, DNET_list);
}

/** Sends our Routing Table, built from our DNET[] array, as an ACK.
 * There are two cases here:
 * 1) We are responding to a NETWORK_MESSAGE_INIT_RT_TABLE requesting our table.
 *    We will normally broadcast that response.
 * 2) We are ACKing the receipt of a NETWORK_MESSAGE_INIT_RT_TABLE containing a
 *    routing table, and then we will want to respond to that dst router.
 *    In that case, DNET[] should just have one entry of -1 (no routing table
 *    is sent).
 * @ingroup NMRC
 *
 * @param dst [in] If NULL, Ack will be broadcast to the local BACnet network.
 *                 Optionally may designate a particular router destination,
 *                 especially when ACKing receipt of this message type.
 * @param DNET_list [in] List of BACnet network numbers for which I am a router,
 *                       terminated with -1.  May be just -1 when no table
 *                       should be sent.
 */
void Send_Initialize_Routing_Table_Ack(
    BACNET_ADDRESS *dst, const int DNET_list[])
{
    Send_Network_Layer_Message(
        NETWORK_MESSAGE_INIT_RT_TABLE_ACK, dst, DNET_list);
}

/**
 * @brief Sets a BACnet network number for the local network
 *
 * @param dst [in] If NULL, request will be broadcast to the local BACnet
 *                 network.  Optionally may designate a particular router
 *                 destination to respond.
 * @param dnet [in] Which BACnet network to request for; if -1, no DNET
 *                 will be sent and the receiving router(s) will send
 *                 their full list of reachable BACnet networks.
 */
void Send_Network_Number_Is(BACNET_ADDRESS *dst, int dnet, int status)
{
    int iArgs[2];
    iArgs[0] = dnet;
    iArgs[1] = status;

    Send_Network_Layer_Message(NETWORK_MESSAGE_NETWORK_NUMBER_IS, dst, iArgs);
}