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On CC3000, trying to decode the end of the Socket Send To HCI message.

Valkyrie-MT
Expert 1050 points

I am trying to figure out the Socket Send command, but I can't figure out what the end is...  the following is my breakdown of a valid working command sent from the Stellaris Launchpad using the sample application.  

Socket Command: Socket Send To 192.168.1.84, port 0xC738, message "12345"

U0Vd9jcl.jpg

 

01 00 33 00 00 - SPI Header, HCI Length of 0x33 or 51 decimal
02 - Write Type
83 18 - opcode 0x1883  (wierd, expected 0x1083)
2D 00 - Payload Length? 45 decimal
00 00 00 00 - Socket ID of 0
14 00 00 00 - Arg size =  SOCKET_SENDTO_PARAMS_LEN(24) - Length of Socket ID (4) = 20 = 0x14; Note: SEND (as opposed to SENDTO) uses HCI_CMND_SEND_ARG_LENGTH(16) - Length of SocketID (4)
05 00 00 00 - Message length
00 00 00 00 - flags (all 0s)
0D 00 00 00 - SENDTO Only - Address offset? Calculated from Message Length(5) + (Size of Message Length(4) x 2) = 5 + (4 x 2) = 0x0D
08 00 00 00 - SENDTO Only - Address Length (always 8?  what about ipv6?  eek!) 
31 32 33 34 35 - THE DATA/MESSAGE (ASCII for "12345")
02 00 C7 38 - 0x0002 is family AF_INET (always and type is short), and 0xC738 is the port (SENDTO Only?)
C0 A8 01 54 - Destination IP 192.168.1.84 (SENDTO Only?)
F9 FF FF FF - ??
CB 12 00 20 - ??
00 - Padding byte

 

Any ideas on the red bits?  

 

Thanks. 

  • 0
    TI__Expert 5295 points

    Hi,

    The last 16 bytes (excluding the padding byte) refer to the destination address.

    This address is defined as:

    typedef struct _sockaddr_t
    {
    unsigned short int sa_family;
    unsigned char sa_data[14];
    } sockaddr;

    where bytes [3,4,5,6] of sa_data represent the destination IP (we only support IPV4) address, and the rest (8 bytes) are actually: sin_zero[8]. It's like a padding structure.

    Regards,

    Tomer

  • 0 in reply to Tomer Kariv
    Expert 1050 points

    Thanks Tomer.  Just the answer I was looking for.  I confirmed that supplying 8 nulls at the end worked just fine.  So, I am going to assume that what I was seeing was just uninitialized values in the array that got sent over with the Sample app. 

    Thanks again.