skarg
98207470f4
When the device is behind a NAT enabled IP router, the local subnet is not accessible from the WAN side. This means that the device's local IP address cannot be used by other devices to communicate with it. The router can port forward BACnet packets to one device in the local network, but to do so other devices need to use the global IP for communication. The considerations and limitations for NAT usage are specified in BACnet standard Annex J.7.8. Thank you, Sami Pietikäinen, for the contribution!
172 lines
6.0 KiB
C
172 lines
6.0 KiB
C
/**************************************************************************
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*
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* Copyright (C) 2012 Steve Karg <skarg@users.sourceforge.net>
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*********************************************************************/
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#ifndef BVLC_H
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#define BVLC_H
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#include <stdbool.h>
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#include <stdint.h>
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#include <stddef.h>
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#include <time.h>
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#include "bacdef.h"
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#include "npdu.h"
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#include "bip.h"
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struct sockaddr_in; /* Defined elsewhere, needed here. */
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#ifdef __cplusplus
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extern "C" {
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#endif /* __cplusplus */
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#if defined(BBMD_ENABLED) && BBMD_ENABLED
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void bvlc_maintenance_timer(
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time_t seconds);
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#else
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#define bvlc_maintenance_timer(x)
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#endif
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typedef struct {
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/* true if valid entry - false if not */
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bool valid;
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/* BACnet/IP address */
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struct in_addr dest_address; /* in network format */
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/* BACnet/IP port number - not always 47808=BAC0h */
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uint16_t dest_port; /* in network format */
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/* Broadcast Distribution Mask */
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struct in_addr broadcast_mask; /* in tework format */
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} BBMD_TABLE_ENTRY;
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uint16_t bvlc_receive(
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BACNET_ADDRESS * src, /* returns the source address */
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uint8_t * npdu, /* returns the NPDU */
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uint16_t max_npdu, /* amount of space available in the NPDU */
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unsigned timeout); /* number of milliseconds to wait for a packet */
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int bvlc_send_pdu(
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BACNET_ADDRESS * dest, /* destination address */
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BACNET_NPDU_DATA * npdu_data, /* network information */
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uint8_t * pdu, /* any data to be sent - may be null */
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unsigned pdu_len);
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int bvlc_send_mpdu(
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struct sockaddr_in *dest,
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uint8_t * mtu,
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uint16_t mtu_len);
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#if defined(BBMD_CLIENT_ENABLED) && BBMD_CLIENT_ENABLED
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int bvlc_encode_write_bdt_init(
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uint8_t * pdu,
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unsigned entries);
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int bvlc_encode_read_fdt(
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uint8_t * pdu);
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int bvlc_encode_delete_fdt_entry(
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uint8_t * pdu,
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uint32_t address, /* in network byte order */
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uint16_t port); /* in network byte order */
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int bvlc_encode_original_unicast_npdu(
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uint8_t * pdu,
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uint8_t * npdu,
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unsigned npdu_length);
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int bvlc_encode_original_broadcast_npdu(
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uint8_t * pdu,
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uint8_t * npdu,
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unsigned npdu_length);
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#endif
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int bvlc_encode_read_bdt(
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uint8_t * pdu);
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int bvlc_bbmd_read_bdt(
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uint32_t bbmd_address,
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uint16_t bbmd_port);
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/* registers with a bbmd as a foreign device */
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int bvlc_register_with_bbmd(
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uint32_t bbmd_address, /* in network byte order */
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uint16_t bbmd_port, /* in network byte order */
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uint16_t time_to_live_seconds);
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/* Note any BVLC_RESULT code, or NAK the BVLL message in the unsupported cases. */
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int bvlc_for_non_bbmd(
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struct sockaddr_in *sout,
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uint8_t * npdu,
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uint16_t received_bytes);
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/* Returns the last BVLL Result we received, either as the result of a BBMD
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* request we sent, or (if not a BBMD or Client), from trying to register
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* as a foreign device. */
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BACNET_BVLC_RESULT bvlc_get_last_result(
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void);
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/* Returns the current BVLL Function Code we are processing.
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* We have to store this higher layer code for when the lower layers
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* need to know what it is, especially to differentiate between
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* BVLC_ORIGINAL_UNICAST_NPDU and BVLC_ORIGINAL_BROADCAST_NPDU. */
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BACNET_BVLC_FUNCTION bvlc_get_function_code(
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void);
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/* Local interface to manage BBMD.
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* The interface user needs to handle mutual exclusion if needed i.e.
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* BACnet packet is not being handled when the BBMD table is modified.
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*/
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/* Get handle to broadcast distribution table. Returns the number of
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* valid entries in the table. */
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int bvlc_get_bdt_local(
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const BBMD_TABLE_ENTRY** table);
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/* Invalidate all entries in the broadcast distribution table */
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void bvlc_clear_bdt_local(void);
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/* Add new entry to broadcast distribution table. Returns true if the new
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* entry was added successfully */
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bool bvlc_add_bdt_entry_local(
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BBMD_TABLE_ENTRY* entry);
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/* NAT handling
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* If the communication between BBMDs goes through a NAT enabled internet
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* router, special considerations are needed as stated in Annex J.7.8.
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*
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* In short, the local IP address of the BBMD is different than the global
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* address which is visible to the other BBMDs or foreign devices. This is
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* why the source address in forwarded messages needs to be changed to the
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* global IP address.
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*
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* For other considerations/limitations see Annex J.7.8.
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*/
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/* Set global IP address of a NAT enabled router which is used in forwarded
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* messages. Enables NAT handling.
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*/
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void bvlc_set_global_address_for_nat(const struct in_addr* addr);
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/* Disable NAT handling of BBMD.
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*/
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void bvlc_disable_nat(void);
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#ifdef __cplusplus
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}
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#endif /* __cplusplus */
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#endif /* */
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