kernel_optimize_test/include/net/sctp
Daniel Borkmann e6d8b64b34 net: sctp: fix and consolidate SCTP checksumming code
This fixes an outstanding bug found through IPVS, where SCTP packets
with skb->data_len > 0 (non-linearized) and empty frag_list, but data
accumulated in frags[] member, are forwarded with incorrect checksum
letting SCTP initial handshake fail on some systems. Linearizing each
SCTP skb in IPVS to prevent that would not be a good solution as
this leads to an additional and unnecessary performance penalty on
the load-balancer itself for no good reason (as we actually only want
to update the checksum, and can do that in a different/better way
presented here).

The actual problem is elsewhere, namely, that SCTP's checksumming
in sctp_compute_cksum() does not take frags[] into account like
skb_checksum() does. So while we are fixing this up, we better reuse
the existing code that we have anyway in __skb_checksum() and use it
for walking through the data doing checksumming. This will not only
fix this issue, but also consolidates some SCTP code with core
sk_buff code, bringing it closer together and removing respectively
avoiding reimplementation of skb_checksum() for no good reason.

As crc32c() can use hardware implementation within the crypto layer,
we leave that intact (it wraps around / falls back to e.g. slice-by-8
algorithm in __crc32c_le() otherwise); plus use the __crc32c_le_combine()
combinator for crc32c blocks.

Also, we remove all other SCTP checksumming code, so that we only
have to use sctp_compute_cksum() from now on; for doing that, we need
to transform SCTP checkumming in output path slightly, and can leave
the rest intact.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-03 23:04:57 -05:00
..
auth.h net: sctp: trivial: update bug report in header comment 2013-08-09 11:33:02 -07:00
checksum.h net: sctp: fix and consolidate SCTP checksumming code 2013-11-03 23:04:57 -05:00
command.h net: sctp: trivial: update bug report in header comment 2013-08-09 11:33:02 -07:00
constants.h net: sctp: trivial: update bug report in header comment 2013-08-09 11:33:02 -07:00
sctp.h sctp: Remove extern from function prototypes 2013-09-23 16:29:42 -04:00
sm.h net: sctp: trivial: update bug report in header comment 2013-08-09 11:33:02 -07:00
structs.h net: sctp: reorder sctp_globals to reduce cacheline usage 2013-08-29 14:55:54 -04:00
tsnmap.h net: sctp: trivial: update bug report in header comment 2013-08-09 11:33:02 -07:00
ulpevent.h net: sctp: trivial: update bug report in header comment 2013-08-09 11:33:02 -07:00
ulpqueue.h net: sctp: trivial: update bug report in header comment 2013-08-09 11:33:02 -07:00