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33 commits

Author SHA1 Message Date
Carlos Garcia
c98be0c96d doc: spelling error changes
Fixed multiple spelling errors.

Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Carlos E. Garcia <carlos@cgarcia.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-05-05 15:32:05 +02:00
Masanari Iida
c17cb8b55b doc:net: Fix typo in Documentation/networking
Correct spelling typo in Documentation/networking

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-30 17:10:20 -04:00
Linus Torvalds
008d23e485 Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits)
  Documentation/trace/events.txt: Remove obsolete sched_signal_send.
  writeback: fix global_dirty_limits comment runtime -> real-time
  ppc: fix comment typo singal -> signal
  drivers: fix comment typo diable -> disable.
  m68k: fix comment typo diable -> disable.
  wireless: comment typo fix diable -> disable.
  media: comment typo fix diable -> disable.
  remove doc for obsolete dynamic-printk kernel-parameter
  remove extraneous 'is' from Documentation/iostats.txt
  Fix spelling milisec -> ms in snd_ps3 module parameter description
  Fix spelling mistakes in comments
  Revert conflicting V4L changes
  i7core_edac: fix typos in comments
  mm/rmap.c: fix comment
  sound, ca0106: Fix assignment to 'channel'.
  hrtimer: fix a typo in comment
  init/Kconfig: fix typo
  anon_inodes: fix wrong function name in comment
  fix comment typos concerning "consistent"
  poll: fix a typo in comment
  ...

Fix up trivial conflicts in:
 - drivers/net/wireless/iwlwifi/iwl-core.c (moved to iwl-legacy.c)
 - fs/ext4/ext4.h

Also fix missed 'diabled' typo in drivers/net/bnx2x/bnx2x.h while at it.
2011-01-13 10:05:56 -08:00
Gerrit Renker
bfbb23466a dccp: make upper bound for seq_window consistent on 32/64 bit
The 'seq_window' sysctl sets the initial value for the DCCP Sequence Window,
which may range from 32..2^46-1 (RFC 4340, 7.5.2). The patch sets the upper
bound consistently to 2^32-1 on both 32 and 64 bit systems, which should be
sufficient - with a RTT of 1sec and 1-byte packets, a seq_window of 2^32-1
corresponds to a link speed of 34 Gbps.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2011-01-07 12:22:44 +01:00
Tomasz Grobelny
871a2c16c2 dccp: Policy-based packet dequeueing infrastructure
This patch adds a generic infrastructure for policy-based dequeueing of
TX packets and provides two policies:
 * a simple FIFO policy (which is the default) and
 * a priority based policy (set via socket options).
Both policies honour the tx_qlen sysctl for the maximum size of the write
queue (can be overridden via socket options).

The priority policy uses skb->priority internally to assign an u32 priority
identifier, using the same ranking as SO_PRIORITY. The skb->priority field
is set to 0 when the packet leaves DCCP. The priority is supplied as ancillary
data using cmsg(3), the patch also provides the requisite parsing routines.

Signed-off-by: Tomasz Grobelny <tomasz@grobelny.oswiecenia.net>
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2010-12-07 13:47:12 +01:00
Michael Witten
c996d8b9a8 Docs/Kconfig: Update: osdl.org -> linuxfoundation.org
Some of the documentation refers to web pages under
the domain `osdl.org'. However, `osdl.org' now
redirects to `linuxfoundation.org'.

Rather than rely on redirections, this patch updates
the addresses appropriately; for the most part, only
documentation that is meant to be current has been
updated.

The patch should be pretty quick to scan and check;
each new web-page url was gotten by trying out the
original URL in a browser and then simply copying the
the redirected URL (formatting as necessary).

There is some conflict as to which one of these domain
names is preferred:

  linuxfoundation.org
  linux-foundation.org

So, I wrote:

  info@linuxfoundation.org

and got this reply:

  Message-ID: <4CE17EE6.9040807@linuxfoundation.org>
  Date: Mon, 15 Nov 2010 10:41:42 -0800
  From: David Ames <david@linuxfoundation.org>

  ...

  linuxfoundation.org is preferred. The canonical name for our web site is
  www.linuxfoundation.org. Our list site is actually
  lists.linux-foundation.org.

  Regarding email linuxfoundation.org is preferred there are a few people
  who choose to use linux-foundation.org for their own reasons.

Consequently, I used `linuxfoundation.org' for web pages and
`lists.linux-foundation.org' for mailing-list web pages and email addresses;
the only personal email address I updated from `@osdl.org' was that of
Andrew Morton, who prefers `linux-foundation.org' according `git log'.

Signed-off-by: Michael Witten <mfwitten@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-11-15 23:50:13 +01:00
Gerrit Renker
89858ad143 dccp ccid-3: use per-route RTO or TCP RTO as fallback
This makes RTAX_RTO_MIN also available to CCID-3, replacing the compile-time
RTO lower bound with a per-route tunable value.

The original Kconfig option solved the problem that a very low RTT (in the
order of HZ) can trigger too frequent and unnecessary reductions of the
sending rate.

This tunable does not affect the initial RTO value of 2 seconds specified in
RFC 5348, section 4.2 and Appendix B. But like the hardcoded Kconfig value,
it allows to adapt to network conditions.

The same effect as the original Kconfig option of 100ms is now achieved by

> ip route replace to unicast 192.168.0.0/24 rto_min 100j dev eth0

(assuming HZ=1000).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-30 13:45:28 -07:00
Gerrit Renker
4886fcad6e dccp ccid-2: Share TCP's minimum RTO code
Using a fixed RTO_MIN of 0.2 seconds was found to cause problems for CCID-2
over 802.11g: at least once per session there was a spurious timeout. It
helped to then increase the the value of RTO_MIN over this link.

Since the problem is the same as in TCP, this patch makes the solution from
commit "05bb1fad1cde025a864a90cfeb98dcbefe78a44a"
       "[TCP]: Allow minimum RTO to be configurable via routing metrics."
available to DCCP.

This avoids reinventing the wheel, so that e.g. the following works in the
expected way now also for CCID-2:

> ip route change 10.0.0.2 rto_min 800 dev ath0

Luckily this useful rto_min function was recently moved to net/tcp.h,
which simplifies sharing code originating from TCP.

Documentation also updated (plus minor whitespace fixes).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-30 13:45:27 -07:00
Gerrit Renker
69a6a0b38a dccp: allow probing of CCID-array length
This fixes a problem in the DCCP getsockopt() API: currently there is no way
for a user to a priori know the number of built-in CCIDs, other than trying
DCCP_SOCKOPT_AVAILABLE_CCIDS in a loop, incrementing the option length until
EINVAL is no longer returned.

This patch truncates the array to the user-provided length. No copy is made
when the length is <= 0.

Due to the length restriction in do_dccp_getsockopt() to sizeof(int), the
minimum array length remains 4, which is a reasonable default (only 3
CCIDs, CCID-2..4, are currently defined).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-02-12 11:47:00 -08:00
Gerrit Renker
792b48780e dccp: Implement both feature-local and feature-remote Sequence Window feature
This adds full support for local/remote Sequence Window feature, from which the
  * sequence-number-validity (W) and
  * acknowledgment-number-validity (W') windows
derive as specified in RFC 4340, 7.5.3.

Specifically, the following is contained in this patch:
  * integrated new socket fields into dccp_sk;
  * updated the update_gsr/gss routines with regard to these fields;
  * updated handler code: the Sequence Window feature is located at the TX side,
    so the local feature is meant if the handler-rx flag is false;
  * the initialisation of `rcv_wnd' in reqsk is removed, since
    - rcv_wnd is not used by the code anywhere;
    - sequence number checks are not done in the LISTEN state (cf. 7.5.3);
    - dccp_check_req checks the Ack number validity more rigorously;
  * the `struct dccp_minisock' became empty and is now removed.

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>
2009-01-21 14:34:04 -08:00
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
Gerrit Renker
4098dce5be dccp: Remove manual influence on NDP Count feature
Updating the NDP count feature is handled automatically now:
 * for CCID-2 it is disabled, since the code does not use NDP counts;
 * for CCID-3 it is enabled, as NDP counts are used to determine loss lengths.

Allowing the user to change NDP values leads to unpredictable and failing
behaviour, since it is then possible to disable NDP counts even when they
are needed (e.g. in CCID-3).

This means that only those user settings are sensible that agree with the
values for Send NDP Count implied by the choice of CCID. But those settings
are already activated by the feature negotiation (CCID dependency tracking),
hence this form of support is redundant.

At startup the initialisation of the NDP count feature uses the default
value of 0, which is done implicitly by the zeroing-out of the socket when
it is allocated. If the choice of CCID or feature negotiation enables NDP
count, this will then be updated via the NDP activation handler.

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 01:18:37 -08:00
Gerrit Renker
0049bab5e7 dccp: Remove obsolete parts of the old CCID interface
The TX/RX CCIDs of the minisock are now redundant: similar to the Ack Vector
case, their value equals initially that of the sysctl, but at the end of
feature negotiation may be something different.

The old interface removed by this patch thus has been replaced by the newer
interface to dynamically query the currently loaded CCIDs.

Also removed are the constructors for the TX CCID and the RX CCID, since the
switch "rx <-> non-rx" is done by the handler in minisocks.c (and the handler
is the only place in the code where CCIDs are loaded).

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 01:18:05 -08:00
Gerrit Renker
b20a9c24d5 dccp: Set per-connection CCIDs via socket options
With this patch, TX/RX CCIDs can now be changed on a per-connection
basis, which overrides the defaults set by the global sysctl variables
for TX/RX CCIDs.

To make full use of this facility, the remaining patches of this patch
set are needed, which track dependencies and activate negotiated
feature values.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-23 16:02:31 -08:00
Gerrit Renker
dd9c0e363c dccp: Deprecate Ack Ratio sysctl
This patch deprecates the Ack Ratio sysctl, since
 * Ack Ratio is entirely ignored by CCID-3 and CCID-4,
 * Ack Ratio currently doesn't work in CCID-2 (i.e. is always set to 1);
 * even if it would work in CCID-2, there is no point for a user to change it:
   - Ack Ratio is constrained by cwnd (RFC 4341, 6.1.2),
   - if Ack Ratio > cwnd, the system resorts to spurious RTO timeouts
     (since waiting for Acks which will never arrive in this window),
   - cwnd is not a user-configurable value.

The only reasonable place for Ack Ratio is to print it for debugging. It is
planned to do this later on, as part of e.g. dccp_probe.

With this patch Ack Ratio is now under full control of feature negotiation:
 * Ack Ratio is resolved as a dependency of the selected CCID;
 * if the chosen CCID supports it (i.e. CCID == CCID-2), Ack Ratio is set to
   the default of 2, following RFC 4340, 11.3 - "New connections start with Ack
   Ratio 2 for both endpoints";
 * what happens then is part of another patch set, since it concerns the
   dynamic update of Ack Ratio while the connection is in full flight.

Thanks to Tomasz Grobelny for discussion leading up to this patch.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-11-16 22:55:08 -08:00
Gerrit Renker
d90ebcbfa7 dccp: Query supported CCIDs
This provides a data structure to record which CCIDs are locally supported
and three accessor functions:
 - a test function for internal use which is used to validate CCID requests
   made by the user;
 - a copy function so that the list can be used for feature-negotiation;   
 - documented getsockopt() support so that the user can query capabilities.

The data structure is a table which is filled in at compile-time with the
list of available CCIDs (which in turn depends on the Kconfig choices).

Using the copy function for cloning the list of supported CCIDs is useful for
feature negotiation, since the negotiation is now with the full list of available
CCIDs (e.g. {2, 3}) instead of the default value {2}. This means negotiation 
will not fail if the peer requests to use CCID3 instead of CCID2. 

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>
2008-11-12 00:47:26 -08:00
Gerrit Renker
b8599d2070 [DCCP]: Support for server holding timewait state
This adds a socket option and signalling support for the case where the server
holds timewait state on closing the connection, as described in RFC 4340, 8.3.

Since holding timewait state at the server is the non-usual case, it is enabled
via a socket option. Documentation for this socket option has been added.

The setsockopt statement has been made resilient against different possible cases
of expressing boolean `true' values using a suggestion by Ian McDonald.

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>
2008-01-28 14:57:48 -08:00
Gerrit Renker
c28149016c [DCCP]: Update documentation on ioctls
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-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>
2008-01-28 14:54:48 -08:00
Gerrit Renker
e333b3edc4 [DCCP]: Promote CCID2 as default CCID
This patch addresses the following problems:

 1. DCCP relies for its proper functioning on having at least one CCID module
    enabled (as in TCP plugable congestion control). Currently it is possible to
    disable both CCIDs and thus leave the DCCP module in a compiled, but entirely
    non-functional state: no sockets can be created when no CCID is available.
    Furthermore, the protocol is (again like TCP) not intended to be used without
    CCIDs. Last, a non-empty CCID list is needed for doing CCID feature negotiation.

 2. Internally the default CCID that is advertised by the Linux host is set to CCID2
    (DCCPF_INITIAL_CCID in include/linux/dccp.h). Disabling CCID2 in the Kconfig
    menu without changing the defaults leads to a failure `module not found' when
    trying to load the dccp module (which internally tries to load the default CCID).

 3. The specification (RFC 4340, sec. 10) treats CCID2 somewhat like a
    `minimum common denominator'; the specification says that:

    * "New connections start with CCID 2 for both endpoints"

    * "A DCCP implementation intended for general use, such as an implementation in a
       general-purpose operating system kernel, SHOULD implement at least CCID 2.
       The intent is to make CCID 2 broadly available for interoperability [...]"

    Providing CCID2 as minimum-required CCID (like Reno/Cubic in TCP) thus seems reasonable.

Hence this patch automatically selects CCID2 when DCCP is enabled. Documentation also added.

Discussions with Ian McDonald on this subject are gratefully acknowledged.

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>
2008-01-28 14:54:46 -08:00
Gerrit Renker
ebe6f7e73c [DCCP]: Update documentation
This updates the DCCP documentation, following input from Ian McDonald,
clarifiying the status of DCCP, and adding a note about the test tree.

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>
2008-01-28 14:54:45 -08:00
Gerrit Renker
8e8c71f1ab [DCCP]: Honour and make use of shutdown option set by user
This extends the DCCP socket API by honouring any shutdown(2) option set by the user.
The behaviour is, as much as possible, made consistent with the API for TCP's shutdown.

This patch exploits the information provided by the user via the socket API to reduce
processing costs:
 * if the read end is closed (SHUT_RD), it is not necessary to deliver to input CCID;
 * if the write end is closed (SHUT_WR), the same idea applies, but with a difference -
   as long as the TX queue has not been drained, we need to receive feedback to keep
   congestion-control rates up to date. Hence SHUT_WR is honoured only after the last
   packet (under congestion control) has been sent;
 * although SHUT_RDWR seems nonsensical, it is nevertheless supported in the same manner
   as for TCP (and agrees with test for SHUTDOWN_MASK in dccp_poll() in net/dccp/proto.c).

Furthermore, most of the code already honours the sk_shutdown flags (dccp_recvmsg() for
instance sets the read length to 0 if SHUT_RD had been called); CCID handling is now added
to this by the present patch.

There will also no longer be any delivery when the socket is in the final stages, i.e. when
one of dccp_close(), dccp_fin(), or dccp_done() has been called - which is fine since at
that stage the connection is its final stages.

Motivation and background are on http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/shutdown

A FIXME has been added to notify the other end if SHUT_RD has been set (RFC 4340, 11.7).

Note: There is a comment in inet_shutdown() in net/ipv4/af_inet.c which asks to "make
      sure the socket is a TCP socket". This should probably be extended to mean
      `TCP or DCCP socket' (the code is also used by UDP and raw sockets).

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>
2008-01-28 14:54:44 -08:00
Gerrit Renker
2bfd754d1b [DCCP]: Correct documentation
This corrects erroneous documentation of the socket API.

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>
2007-10-10 16:54:37 -07:00
Gerrit Renker
126acd5bf7 [DCCP]: Update API documentation
This adds documentation on the use of service codes on client and
server.

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>
2007-10-10 16:54:32 -07:00
Gerrit Renker
7c559a9e44 [DCCP]: Add socket option to query the current MPS
This enables applications to query the current value of the Maximum
Packet Size via a socket option, suggested as a SHOULD in (RFC 4340,
p. 102).

This socket option is useful to avoid the annoying bail-out via
`-EMSGSIZE'.  In particular, as fragmentation is not currently
supported (and its use is partly discouraged in RFC 4340).

With this option, it is possible to size buffers accordingly, e.g.

	int buflen = dccp_get_cur_mps(sockfd);

	/* or */
	if (msgsize > dccp_get_cur_mps(sockfd))
		die("message is too large for this path");

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>
2007-10-10 16:54:31 -07:00
Gerrit Renker
a94f0f9705 [DCCP]: Rate-limit DCCP-Syncs
This implements a SHOULD from RFC 4340, 7.5.4:
 "To protect against denial-of-service attacks, DCCP implementations SHOULD
  impose a rate limit on DCCP-Syncs sent in response to sequence-invalid packets,
  such as not more than eight DCCP-Syncs per second."

The rate-limit is maintained on a per-socket basis. This is a more stringent
policy than enforcing the rate-limit on a per-source-address basis and
protects against attacks with forged source addresses.

Moreover, the mechanism is deliberately kept simple. In contrast to
xrlim_allow(), bursts of Sync packets in reply to sequence-invalid packets
are not supported.  This foils such attacks where the receipt of a Sync
triggers further sequence-invalid packets. (I have tested this mechanism against
xrlim_allow algorithm for Syncs, permitting bursts just increases the problems.)

In order to keep flexibility, the timeout parameter can be set via sysctl; and
the whole mechanism can even be disabled (which is however not recommended).

The algorithm in this patch has been improved with regard to wrapping issues
thanks to a suggestion by Arnaldo.

Commiter note: Rate limited the step 6 DCCP_WARN too, as it says we're
               sending a sync.

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@ghostprotocols.net>
2007-10-10 16:52:43 -07:00
Gerrit Renker
f264510135 [CCID3]: Add documentation for socket options
This updates the documentation on CCID3-specific options.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-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>
2007-04-25 22:26:55 -07:00
Ian McDonald
5fce9a2da8 [DCCP]: Update documentation
As Eddie Kohler points out the RFC is Proposed Standard not experimental.
Also removed documentation about deprecated socket option.

Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-12-11 14:34:38 -08:00
Ian McDonald
82e3ab9dbe [DCCP]: Adds the tx buffer sysctls
This one got lost on the way from Ian to Gerrit to me, fix it.

Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-12-02 21:24:42 -08:00
Ian McDonald
ddfe10b824 [DCCP]: Update Documentation
This patch just updates DCCP documentation a bit.

Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-12-02 21:24:40 -08:00
Gerrit Renker
2e2e9e92bd [DCCP]: Add sysctls to control retransmission behaviour
This adds 3 sysctls which govern the retransmission behaviour of DCCP control
packets (3way handshake, feature negotiation).

It removes 4 FIXMEs from the code.

The close resemblance of sysctl variables to their TCP analogues is emphasised
not only by their name, but also by giving them the same initial values.
This is useful since there is not much practical experience with DCCP yet.

Furthermore, with regard to the previous patch, it is now possible to limit
the number of keepalive-Responses by setting net.dccp.default.request_retries
(also a bit like in TCP).

Lastly, added documentation of all existing DCCP sysctls.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-12-02 21:22:18 -08:00
Gerrit Renker
6f4e5fff1e [DCCP]: Support for partial checksums (RFC 4340, sec. 9.2)
This patch does the following:
  a) introduces variable-length checksums as specified in [RFC 4340, sec. 9.2]
  b) provides necessary socket options and documentation as to how to use them
  c) basic support and infrastructure for the Minimum Checksum Coverage feature
     [RFC 4340, sec. 9.2.1]: acceptability tests, user notification and user
     interface

In addition, it

 (1) fixes two bugs in the DCCPv4 checksum computation:
 	* pseudo-header used checksum_len instead of skb->len
	* incorrect checksum coverage calculation based on dccph_x
 (2) removes dccp_v4_verify_checksum() since it reduplicates code of the
     checksum computation; code calling this function is updated accordingly.
 (3) now uses skb_checksum(), which is safer than checksum_partial() if the
     sk_buff has is a non-linear buffer (has pages attached to it).
 (4) fixes an outstanding TODO item:
        * If P.CsCov is too large for the packet size, drop packet and return.

The code has been tested with applications, the latest version of tcpdump now
comes with support for partial DCCP checksums.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-12-02 21:22:09 -08:00
Gerrit Renker
00e4d116a7 [DCCP]: Allow default/fallback service code.
This has been discussed on dccp@vger and removes the necessity for applications
to supply service codes in each and every case.

If an application does not want to provide a service code, that's fine, it will
be given 0. Otherwise, service codes can be set via socket options as before.

This patch has been tested using various client/server configurations
(including listening on multiple service codes).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
2006-09-24 17:49:26 -03:00
Ian McDonald
98069ff4ec [DCCP]: Create Documentation/networking/dccp.txt
This patch is a first go at some documentation. Please advise if gmail
has mangled patch and I will revert to an attachment:

Signed-off-by: Ian McDonald <imcdnzl@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-10 13:04:33 -08:00