]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
[DCCP]: Add (missing) option parsing to request_sock processing
authorGerrit Renker <gerrit@erg.abdn.ac.uk>
Thu, 13 Dec 2007 14:31:26 +0000 (12:31 -0200)
committerDavid S. Miller <davem@davemloft.net>
Mon, 28 Jan 2008 22:57:50 +0000 (14:57 -0800)
commit8109616e2ef978d142ea45850efd4f102b9bdce4
tree338aa4e2bf9d9424090b0d698d20b3c465cf229c
parent8b819412481494fb6861c08d360b75fabcbbfbbf
[DCCP]: Add (missing) option parsing to request_sock processing

This adds option-parsing code to processing of Acks in the listening state
on request_socks on the server, serving two purposes
 (i)  resolves a FIXME (removed);
 (ii) paves the way for feature-negotiation during connection-setup.

There is an intended subtlety here with regard to dccp_check_req:

 Parsing options happens only after testing whether the received packet is
 a retransmitted Request.  Otherwise, if the Request contained (a possibly
 large number of) feature-negotiation options, recomputing state would have to
 happen each time a retransmitted Request arrives, which opens the door to an
 easy DoS attack.  Since in a genuine retransmission the options should not be
 different from the original, reusing the already computed state seems better.

 The other point is - if there are timestamp options on the Request, they will
 not be answered; which means that in the presence of retransmission (likely
 due to loss and/or other problems), the use of Request/Response RTT sampling
 is suspended, so that startup problems here do not propagate.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/dccp/minisocks.c