How to use TCP Checksum Off-load in my network driver

Question

I am seeking infomation on how to use TCP Checksum Off-load to tell the Solaris 8 stack not to handle it for both receives and transmits (and let our NIC handle this compute-intensive task instead).
There is mention that Sun GigabitEthernet Adapter cards, Release 1.1 supports Sol-2.6 use of NIC features: TCP checksum offload & byte swapping
There are limited bits of info in include files. For example
sys/strick.h indicates use of:
inetcksum_t's ick_xmit
stream.h has:
struct datab's unsigned u16:16; /* used to store hw-calculated cksum
#define STRUIO_IP 0x04 /* IP checksum stored in db_struioun */
#define STRUIO_ZC 0x08 /* mblk eligible for zero-copy */
strsub.h has:
struct zero_copy_kstat
Also /include/inet/tcp.h has tcp_sum for outbound.
Thank you. -Weimin Tchen

Answer 1

VenK7337,
Could you show your python code. so we know what your are "writing" to the ethernet port?
That way we can see what you are receiving.
Parsing the incoming data (from the TCP-read) depends heavily on the device that sends it, and can not generically be described. LabVIEW has many byte (and even bit) manipulation functions to convert many different data formats to its own build in formats.
So after the TCP listener is connected, you are constantly reading from the established connection (until it gets broken of course). More advanced example would be the internet toolkit if oyu have it.
From the read characters (and I hope you designed a protocol with a clear starting character, ending character and maybe even a build in checksum) you parse the data and perform you action, and of course generate a reply. Again the internet toolkit is a good example. It parsed the input as it comes it, based on the HTTP format. Then generates the reply based on the request received.
These days I would suggest not to use binairy encoded numerics. Try and use XML formatted data. Yes, it causes a lot of overhead. But typically this is not an issue and makes the code a lot more portable and maintainable. Also makes it easier to interface with other languages/platforms.
Umless of course you are looking at Khz data rates, then XML is not th preferred choice.
Hope this helps...