tree 3952d784c9d7c061a5ff7c0e23277783f10e55d2
parent 4833ed094097323f5f219820f6ebdc8dd66f501f
author Al Viro <viro@zeniv.linux.org.uk> 1162542503 -0800
committer David S. Miller <davem@sunset.davemloft.net> 1162764685 -0800

[IPX]: Annotate and fix IPX checksum

Calculation of IPX checksum got buggered about 2.4.0.  The old variant
mangled the packet; that got fixed, but calculation itself got buggered.
Restored the correct logics, fixed a subtle breakage we used to have even
back then: if the sum is 0 mod 0xffff, we want to return 0, not 0xffff.
The latter has special meaning for IPX (cheksum disabled).  Observation
(and obvious fix) nicked from history of FreeBSD ipx_cksum.c...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>