hi,

> Does the rtl8169 support tcp segment offload?  If not, then the 
> assignment doesn't matter.

yes, it does.

> If so, *what* would be a sensible value in 
> this situation?

although i'm not sure about the exact requirement,
it works fine if i commented out the "ip->ip_len = 0;".
(i think it's what linux does.)

YAMAMOTO Takashi