TX Checksum offloading issue with re interfaces

[Michael Tuexen]

Dear all,

while testing checksum offloading of UDP packets over IP with IP options, I figured
out that my card

dev.re.1.%desc: RealTek 8168/8111 B/C/CP/D/DP/E/F/G PCIe Gigabit Ethernet
dev.re.1.%driver: re
dev.re.1.%location: slot=0 function=0 handle=\_SB_.PCI0.PE1F.LAN2
dev.re.1.%pnpinfo: vendor=0x10ec device=0x8168 subvendor=0x1734 subdevice=0x1159 class=0x020000
dev.re.1.%parent: pci13
dev.re.1.stats: -1
dev.re.1.int_rx_mod: 65

computes the UDP checksum, but stores it in the packet at the place, where it would be,
if there are no IP options. So it corrupts the options in the packet...

I looked at sys/dev/re/if_re.c, but couldn't figure out how to fix it. Any idea?

Best regards
Michael