linux/net/dccp
Gerrit Renker 6fdd34d43b dccp ccid-2: Phase out the use of boolean Ack Vector sysctl
This removes the use of the sysctl and the minisock variable for the Send Ack
Vector feature, as it now is handled fully dynamically via feature negotiation
(i.e. when CCID-2 is enabled, Ack Vectors are automatically enabled as per
 RFC 4341, 4.).

Using a sysctl in parallel to this implementation would open the door to
crashes, since much of the code relies on tests of the boolean minisock /
sysctl variable. Thus, this patch replaces all tests of type

	if (dccp_msk(sk)->dccpms_send_ack_vector)
		/* ... */
with
	if (dp->dccps_hc_rx_ackvec != NULL)
		/* ... */

The dccps_hc_rx_ackvec is allocated by the dccp_hdlr_ackvec() when feature
negotiation concluded that Ack Vectors are to be used on the half-connection.
Otherwise, it is NULL (due to dccp_init_sock/dccp_create_openreq_child),
so that the test is a valid one.

The activation handler for Ack Vectors is called as soon as the feature
negotiation has concluded at the
 * server when the Ack marking the transition RESPOND => OPEN arrives;
 * client after it has sent its ACK, marking the transition REQUEST => PARTOPEN.

Adding the sequence number of the Response packet to the Ack Vector has been
removed, since
 (a) connection establishment implies that the Response has been received;
 (b) the CCIDs only look at packets received in the (PART)OPEN state, i.e.
     this entry will always be ignored;
 (c) it can not be used for anything useful - to detect loss for instance, only
     packets received after the loss can serve as pseudo-dupacks.

There was a FIXME to change the error code when dccp_ackvec_add() fails.
I removed this after finding out that:
 * the check whether ackno < ISN is already made earlier,
 * this Response is likely the 1st packet with an Ackno that the client gets,
 * so when dccp_ackvec_add() fails, the reason is likely not a packet error.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-12-08 01:19:06 -08:00
..
ccids dccp: Registration routines for changing feature values 2008-11-12 00:43:40 -08:00
ackvec.c dccp: Set per-connection CCIDs via socket options 2008-11-23 16:02:31 -08:00
ackvec.h dccp: Set per-connection CCIDs via socket options 2008-11-23 16:02:31 -08:00
ccid.c dccp: Remove obsolete parts of the old CCID interface 2008-12-08 01:18:05 -08:00
ccid.h dccp: Remove obsolete parts of the old CCID interface 2008-12-08 01:18:05 -08:00
dccp.h dccp ccid-2: Phase out the use of boolean Ack Vector sysctl 2008-12-08 01:19:06 -08:00
diag.c dccp ccid-2: Phase out the use of boolean Ack Vector sysctl 2008-12-08 01:19:06 -08:00
feat.c dccp: Remove manual influence on NDP Count feature 2008-12-08 01:18:37 -08:00
feat.h dccp: Clean up old feature-negotiation infrastructure 2008-12-08 01:17:32 -08:00
input.c dccp ccid-2: Phase out the use of boolean Ack Vector sysctl 2008-12-08 01:19:06 -08:00
ipv4.c net: Convert TCP & DCCP hash tables to use RCU / hlist_nulls 2008-11-16 19:40:17 -08:00
ipv6.c netns xfrm: lookup in netns 2008-11-25 17:35:18 -08:00
ipv6.h Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
Kconfig This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp" 2008-09-09 13:27:22 +02:00
Makefile This reverts "Merge branch 'dccp' of git://eden-feed.erg.abdn.ac.uk/dccp_exp" 2008-09-09 13:27:22 +02:00
minisocks.c dccp ccid-2: Phase out the use of boolean Ack Vector sysctl 2008-12-08 01:19:06 -08:00
options.c dccp ccid-2: Phase out the use of boolean Ack Vector sysctl 2008-12-08 01:19:06 -08:00
output.c dccp: use roundup instead of opencoding 2008-12-05 22:39:49 -08:00
probe.c dccp: API to query the current TX/RX CCID 2008-11-23 16:04:59 -08:00
proto.c dccp ccid-2: Phase out the use of boolean Ack Vector sysctl 2008-12-08 01:19:06 -08:00
sysctl.c dccp ccid-2: Phase out the use of boolean Ack Vector sysctl 2008-12-08 01:19:06 -08:00
timer.c dccp: Limit feature negotiation to connection setup phase 2008-11-12 00:42:58 -08:00