Comment 7 for bug 326406

ybaruss:
I just reran the wireshark test on my maverick 10.10 (latest updates) 64-bit system with a Broadcom Corporation NetXtreme BCM5722 Gigabit Ethernet PCI Express.

I got the following results, which are similar to before:
TCP checksums are about 90% incorrect with tx checksum on
TCP checksums are never incorrect (always correct) with tx checksum off
UDP checksums are always incorrect with tx checksum on
UDP checksums are never incorrect (always correct) with tx checksum off

Ybaruss: I believe the bug is not in wireshark, but instead wireshark is identifying the bug in the kernel. Based on my understanding off checksum offloading, I believe that whether it is enabled or not, it should always generate the correct checksum. If there was no buggy behavior in the kernel, we would have the same results in wireshark. The fact that it generates different results for enabled vs disabled implies that there is a bug in the kernel that causes incorrect checksums, depending on the tx offload state.