[Info-vax] Trying to read form an ethernet port using NMA$C_PCLI_MCA to filter multicast packets...

[john.weed at triangleexperience.com]

Hey folks, 

I've been beating my head against a dull rock here; trying to do a simple filtered multicast read against a port on my rx2660. I've done this before, many years ago, and for some reason it simply isn't working now. I have a PC on the network running wire shark and it sees the packets just fine, with the expected destination address and protocol type. Source address matches the hardware address of the sending rx2660. 

If I just IO$_SETMODE the interface with NMA$C_PCLI_PRM set to NMA$C_STATE_ON, the packets come in fine. If, however, I try to set up the port for the protocol type (56-78) and NMA$C_PCLI_MCA set to a single multicast address (AB-00-04-00-12-34), I get nothing. 

Here is the code the runs in promiscuous mode that works...

        LOCAL
            Channel : UNSIGNED WORD INITIAL (0),
            IO_Buffer : $BBLOCK [8192],
            IO_Buffer_Len : INITIAL (%ALLOCATION (IO_Buffer)),
            IO_Status_Block : $BBLOCK [IOSB$C_LENGTH],
            P2_Mode_Buffer      : BLOCK [18, BYTE]
                                  PRESET (
                                  [ 0, 0, 16, 0] = NMA$C_PCLI_ACC,
                                  [ 2, 0, 16, 0] = NMA$C_ACC_EXC,
                                  [ 4, 0, 16, 0] = 0,
                                  [ 6, 0, 16, 0] = NMA$C_PCLI_FMT,
                                  [10, 0, 16, 0] = 0,
                                  [12, 0, 16, 0] = NMA$C_PCLI_PRM,
                                  [14, 0, 16, 0] = NMA$C_STATE_ON,
                                  [16, 0, 16, 0] = 0),
            P2_Mode_Desc        : VECTOR [2, LONG]
                                  PRESET ([0] = %ALLOCATION (P2_Mode_Buffer), [1] = P2_Mode_Buffer),
            P5_Header_Info      : $BBLOCK [64],
            Status;

        Status = $ASSIGN (DEVNAM=%ASCID '_EWB0:', CHAN=Channel);

        IF NOT .Status THEN $EXIT (CODE=.Status);

        Status = $QIOW (
            EFN=EFN$C_ENF,
            CHAN=.Channel,
            FUNC=IO$_SETMODE+IO$M_CTRL+IO$M_STARTUP,
            IOSB=IO_Status_Block,
            P2=P2_Mode_Desc);

        IF .Status THEN Status = .IO_Status_Block [IOSB$W_STATUS];

        IF NOT .Status THEN $EXIT (CODE=.Status);

        Status = $QIOW (
            EFN=EFN$C_ENF,
            CHAN=.Channel,
            FUNC=IO$_READVBLK,
            IOSB=IO_Status_Block,
            P1=IO_Buffer,
            P2=.IO_Buffer_Len,
            P5=P5_Header_Info);

        IF .Status THEN Status = .IO_Status_Block [IOSB$W_STATUS];

        IF NOT .Status THEN $EXIT (CODE=.Status);

Next, here is the code I am trying to get to work that filters for the multicast address AB0004001234 and protocol 5678.. which does not work (not packets received)

        LOCAL
            Channel : UNSIGNED WORD INITIAL (0),
            IO_Buffer : $BBLOCK [8192],
            IO_Buffer_Len : INITIAL (%ALLOCATION (IO_Buffer)),
            IO_Status_Block : $BBLOCK [IOSB$C_LENGTH],
            P2_Mode_Buffer      : BLOCK [36, BYTE]
                                  PRESET (
                                  [ 0, 0, 16, 0] = NMA$C_PCLI_ACC,
                                  [ 2, 0, 16, 0] = NMA$C_ACC_EXC,
                                  [ 4, 0, 16, 0] = 0,
                                  [ 6, 0, 16, 0] = NMA$C_PCLI_FMT,
                                  [ 8, 0, 16, 0] = NMA$C_LINFM_ETH,
                                  [10, 0, 16, 0] = 0,
                                  [12, 0, 16, 0] = NMA$C_PCLI_PRM,
                                  [14, 0, 16, 0] = NMA$C_STATE_OFF,
                                  [16, 0, 16, 0] = 0,
                                  [18, 0, 16, 0] = NMA$C_PCLI_PTY,
                                  [20, 0, 16, 0] = %x'7856',
                                  [22, 0, 16, 0] = 0,
                                  [24, 0, 16, 0] = NMA$C_PCLI_MCA,
                                  [26, 0, 16, 0] = 8,
                                  [28, 0, 16, 0] = NMA$C_LINMC_SET,
                                  [30, 0,  8, 0] = %x'AB',
                                  [31, 0,  8, 0] = %x'00',
                                  [32, 0,  8, 0] = %x'04',
                                  [33, 0,  8, 0] = %x'00',
                                  [34, 0,  8, 0] = %x'12',
                                  [35, 0,  8, 0] = %x'34'),
            P2_Mode_Desc        : VECTOR [2, LONG]
                                  PRESET ([0] = %ALLOCATION (P2_Mode_Buffer), [1] = P2_Mode_Buffer),
            P5_Header_Info      : $BBLOCK [64],
            Status;

        Status = $ASSIGN (DEVNAM=%ASCID '_EWB0:', CHAN=Channel);

        IF NOT .Status THEN $EXIT (CODE=.Status);

        Status = $QIOW (
            EFN=EFN$C_ENF,
            CHAN=.Channel,
            FUNC=IO$_SETMODE+IO$M_CTRL+IO$M_STARTUP,
            IOSB=IO_Status_Block,
            P2=P2_Mode_Desc);

        IF .Status THEN Status = .IO_Status_Block [IOSB$W_STATUS];

        IF NOT .Status THEN $EXIT (CODE=.Status);

        Status = $QIOW (
            EFN=EFN$C_ENF,
            CHAN=.Channel,
            FUNC=IO$_READVBLK,
            IOSB=IO_Status_Block,
            P1=IO_Buffer,
            P2=.IO_Buffer_Len,
            P5=P5_Header_Info);

        IF .Status THEN Status = .IO_Status_Block [IOSB$W_STATUS];

        IF NOT .Status THEN $EXIT (CODE=.Status);

This is using the embedded controller of the rx2660 (EWA or EWB). 

Anyone have any good, working examples of reading multicast Ethernet frames using the NMA$C_PCLI_MCA setting?