Discard confirmed APDU from original broadcast in BIP and BIP6 datalink (#149)

Co-authored-by: Steve Karg <skarg@users.sourceforge.net>

src/bacnet/basic/bbmd/h_bbmd.c

@@ -37,6 +37,7 @@
 #include <stdbool.h> /* for the standard bool type. */
 #include <string.h> /* for memcpy */
 #include "bacnet/bacdcode.h"
+#include "bacnet/npdu.h"
 #include "bacnet/datalink/bip.h"
 #include "bacnet/datalink/bvlc.h"
 #include "bacnet/basic/sys/debug.h"
@@ -663,6 +664,7 @@ int bvlc_bbmd_disabled_handler(BACNET_IP_ADDRESS *addr,
     int function_len = 0;
     uint8_t *pdu = NULL;
     uint16_t pdu_len = 0;
+    uint8_t *npdu = NULL;
     uint16_t npdu_len = 0;
     bool send_result = false;
     uint16_t offset = 0;
@@ -765,8 +767,20 @@ int bvlc_bbmd_disabled_handler(BACNET_IP_ADDRESS *addr,
                 if (function_len) {
                     bvlc_ip_address_to_bacnet_local(src, addr);
                     offset = header_len + function_len - npdu_len;
-                    debug_print_npdu(
+                    /* BTL test: verifies that the IUT will quietly discard any
-                        "Original-Broadcast-NPDU", offset, npdu_len);
+                       Confirmed-Request-PDU, whose destination address is a
+                       multicast or broadcast address, received from the
+                       network layer. */
+                    npdu = &mtu[offset];
+                    if (npdu_confirmed_service(npdu, npdu_len)) {
+                        offset = 0;
+                        debug_print_string(
+                            "Original-Broadcast-NPDU: "
+                            "Confirmed Service! Discard!");
+                    } else {
+                        debug_print_npdu(
+                            "Original-Broadcast-NPDU", offset, npdu_len);
+                    }
                 } else {
                     debug_print_string(
                         "Original-Broadcast-NPDU: Unable to decode!");
@@ -1075,9 +1089,21 @@ int bvlc_bbmd_enabled_handler(BACNET_IP_ADDRESS *addr,
                    shall be sent directly to each foreign device currently in
                    the BBMD's FDT also using the BVLL Forwarded-NPDU message. */
                 npdu = &mtu[offset];
-                bbmd_fdt_forward_npdu(addr, npdu, npdu_len, true);
+                /* BTL test: verifies that the IUT will quietly discard any
-                bbmd_bdt_forward_npdu(addr, npdu, npdu_len, true);
+                   Confirmed-Request-PDU, whose destination address is a
-                debug_print_npdu("Original-Broadcast-NPDU", offset, npdu_len);
+                   multicast or broadcast address, received from the
+                   network layer. */
+                if (npdu_confirmed_service(npdu, npdu_len)) {
+                    offset = 0;
+                    debug_print_string(
+                        "Original-Broadcast-NPDU: "
+                        "Confirmed Service! Discard!");
+                } else {
+                    bbmd_fdt_forward_npdu(addr, npdu, npdu_len, true);
+                    bbmd_bdt_forward_npdu(addr, npdu, npdu_len, true);
+                    debug_print_npdu("Original-Broadcast-NPDU",
+                        offset, npdu_len);
+                }
             } else {
                 debug_print_string(
                     "Original-Broadcast-NPDU: Unable to decode!");

src/bacnet/basic/bbmd6/h_bbmd6.c

@@ -615,6 +615,7 @@ int bvlc6_bbmd_disabled_handler(BACNET_IP6_ADDRESS *addr,
     int function_len = 0;
     uint8_t *pdu = NULL;
     uint16_t pdu_len = 0;
+    uint8_t *npdu = NULL;
     uint16_t npdu_len = 0;
     bool send_result = false;
     uint16_t offset = 0;
@@ -696,6 +697,18 @@ int bvlc6_bbmd_disabled_handler(BACNET_IP6_ADDRESS *addr,
                         bbmd6_add_vmac(vmac_src, addr);
                         bvlc6_vmac_address_set(src, vmac_src);
                         offset = header_len + (function_len - npdu_len);
+                        /* BTL test: verifies that the IUT will quietly
+                           discard any Confirmed-Request-PDU, whose
+                           destination address is a multicast or
+                           broadcast address, received from the
+                           network layer. */
+                        npdu = &mtu[offset];
+                        if (npdu_confirmed_service(npdu, npdu_len)) {
+                            offset = 0;
+                            debug_printf(
+                                "BIP6: Original-Broadcast-NPDU: "
+                                "Confirmed Service! Discard!");
+                        }
                     } else {
                         debug_printf("BIP6: Original-Broadcast-NPDU: Unable to "
                                      "decode!\n");
@@ -853,18 +866,30 @@ int bvlc6_bbmd_enabled_handler(BACNET_IP6_ADDRESS *addr,
                 if (function_len) {
                     offset = header_len + (function_len - npdu_len);
                     npdu = &mtu[offset];
-                    /*  Upon receipt of a BVLL Original-Broadcast-NPDU
+                    /* BTL test: verifies that the IUT will quietly
-                        message from the local multicast domain, a BBMD
+                       discard any Confirmed-Request-PDU, whose
-                        shall construct a BVLL Forwarded-NPDU message and
+                       destination address is a multicast or
-                        unicast it to each entry in its BDT. In addition,
+                       broadcast address, received from the
-                        the constructed BVLL Forwarded-NPDU message shall
+                       network layer. */
-                        be unicast to each foreign device currently in
+                    if (npdu_confirmed_service(npdu, npdu_len)) {
-                        the BBMD's FDT */
+                        offset = 0;
-                    BVLC6_Buffer_Len = bvlc6_encode_forwarded_npdu(
+                        debug_printf(
-                        &BVLC6_Buffer[0], sizeof(BVLC6_Buffer), vmac_src, addr,
+                            "BIP6: Original-Broadcast-NPDU: "
-                        npdu, npdu_len);
+                            "Confirmed Service! Discard!");
-                    bbmd6_send_pdu_bdt(&BVLC6_Buffer[0], BVLC6_Buffer_Len);
+                    } else {
-                    bbmd6_send_pdu_fdt(&BVLC6_Buffer[0], BVLC6_Buffer_Len);
+                        /*  Upon receipt of a BVLL Original-Broadcast-NPDU
+                            message from the local multicast domain, a BBMD
+                            shall construct a BVLL Forwarded-NPDU message and
+                            unicast it to each entry in its BDT. In addition,
+                            the constructed BVLL Forwarded-NPDU message shall
+                            be unicast to each foreign device currently in
+                            the BBMD's FDT */
+                        BVLC6_Buffer_Len = bvlc6_encode_forwarded_npdu(
+                            &BVLC6_Buffer[0], sizeof(BVLC6_Buffer), vmac_src,
+                            addr, npdu, npdu_len);
+                        bbmd6_send_pdu_bdt(&BVLC6_Buffer[0], BVLC6_Buffer_Len);
+                        bbmd6_send_pdu_fdt(&BVLC6_Buffer[0], BVLC6_Buffer_Len);
+                    }
                     if (!bbmd6_address_match_self(addr)) {
                         /* The Virtual MAC address table shall be updated
                            using the respective parameter values of the

src/bacnet/datalink/datalink.h

@@ -84,6 +84,7 @@ void routed_get_my_address(
 #elif defined(BACDL_BIP6)
 #include "bacnet/datalink/bip6.h"
 #include "bacnet/datalink/bvlc6.h"
+#include "bacnet/basic/bbmd6/h_bbmd6.h"
 #define datalink_init bip6_init
 #define datalink_send_pdu bip6_send_pdu
 #define datalink_receive bip6_receive

src/bacnet/npdu.c

@@ -501,6 +501,38 @@ int bacnet_npdu_decode(uint8_t *npdu,
     return len;
 }
 
+/**
+ * @brief Helper for datalink detecting an application confirmed service
+ * @param pdu [in]  Buffer containing the NPDU and APDU of the received packet.
+ * @param pdu_len [in] The size of the received message in the pdu[] buffer.
+ * @return true if the PDU is a confirmed APDU
+ */
+bool npdu_confirmed_service(
+    uint8_t *pdu,
+    uint16_t pdu_len)
+{
+    bool status = false;
+    int apdu_offset = 0;
+    BACNET_NPDU_DATA npdu_data = { 0 };
+
+    if (pdu_len > 0) {
+        if (pdu[0] == BACNET_PROTOCOL_VERSION) {
+            /* only handle the version that we know how to handle */
+            apdu_offset =
+                bacnet_npdu_decode(&pdu[0], pdu_len, NULL, NULL, &npdu_data);
+            if ((!npdu_data.network_layer_message) && (apdu_offset > 0) &&
+                (apdu_offset < pdu_len)) {
+                if ((pdu[apdu_offset] & 0xF0) ==
+                    PDU_TYPE_CONFIRMED_SERVICE_REQUEST) {
+                    status = true;
+                }
+            }
+        }
+    }
+
+    return status;
+}
+
 #ifdef BAC_TEST
 #include <assert.h>
 #include <string.h>

src/bacnet/npdu.h

@@ -103,6 +103,11 @@ extern "C" {
         BACNET_ADDRESS * src,
         BACNET_NPDU_DATA * npdu_data);
 
+    BACNET_STACK_EXPORT
+    bool npdu_confirmed_service(
+        uint8_t *pdu,
+        uint16_t pdu_len);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */