tree da4d7a6ff4811d9f38b81c70f08b221b575e1254
parent 7115e632f90952454ab6426e0d2151327162a30f
author Vlad Yasevich <vladislav.yasevich@hp.com> 1213916898 -0700
committer David S. Miller <davem@davemloft.net> 1213916898 -0700

sctp: Follow security requirement of responding with 1 packet

RFC 4960, Section 11.4. Protection of Non-SCTP-Capable Hosts

When an SCTP stack receives a packet containing multiple control or
DATA chunks and the processing of the packet requires the sending of
multiple chunks in response, the sender of the response chunk(s) MUST
NOT send more than one packet.  If bundling is supported, multiple
response chunks that fit into a single packet MAY be bundled together
into one single response packet.  If bundling is not supported, then
the sender MUST NOT send more than one response chunk and MUST
discard all other responses.  Note that this rule does NOT apply to a
SACK chunk, since a SACK chunk is, in itself, a response to DATA and
a SACK does not require a response of more DATA.

We implement this by not servicing our outqueue until we reach the end
of the packet.  This enables maximum bundling.  We also identify
'response' chunks and make sure that we only send 1 packet when sending
such chunks.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>