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author | Daniel Borkmann <dborkman@redhat.com> | 2013-10-30 11:50:52 +0100 |
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committer | David S. Miller <davem@davemloft.net> | 2013-11-03 23:04:57 -0500 |
commit | e6d8b64b34aa8a9fe39609bc2db8a243b0331ceb (patch) | |
tree | de3bbb3dc4e08fd17fcde46aedb239d274e45d6b /mm | |
parent | 2817a336d4d533fb8b68719723cd60ea7dd7c09e (diff) | |
download | op-kernel-dev-e6d8b64b34aa8a9fe39609bc2db8a243b0331ceb.zip op-kernel-dev-e6d8b64b34aa8a9fe39609bc2db8a243b0331ceb.tar.gz |
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>
Diffstat (limited to 'mm')
0 files changed, 0 insertions, 0 deletions