This patch
 * removes setting t_RTO in ccid3_hc_tx_init (per [RFC 3448, 4.2], t_RTO is
   undefined until feedback has been received);

 * makes some trivial changes (updates of comments);

 * performs a small optimisation by exploiting that the feedback timeout
   uses the value of t_ipi. The way it is done is safe, because the timeouts
   appear after the changes to t_ipi, ensuring that up-to-date values are used;

 * in ccid3_hc_tx_packet_recv, moves the t_rto statement closer to the calculation
   of the next_tmout. This makes the code clearer to read and is also safe, since
   t_rto is not updated until the next call of ccid3_hc_tx_packet_recv, and is not
   read by the functions called via ccid_wait_for_ccid();

 * removes a `max' statement in sk_reset_timer, this is not needed since the timeout
   value is always greater than 1E6 microseconds.

 * adds `XXX'es to highlight that currently the nofeedback timer is set
   in a non-standard way
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This patch:

 * consolidates updating of parameters (t_nom, t_ipi, t_delta) which
   need to be updated at the same time, since they are inter-dependent

 * removes two inline functions which are no longer needed as a result of
   the above consolidation

 * resolves a FIXME regarding the re-calculation of t_ipi within the nofeedback
   timer, in the state where no feedback has previously been received

 * ties updating these parameters to updating the sending rate X, exploiting
   that all three parameters in turn depend on X; and using a small optimisation
   which can reduce the number of required instructions: only update the three
   parameters when X really changes
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This patch concerns updating the value of the nofeedback timer when no feedback
has been received so far.

Since in this case the value of R is still undefined according to [RFC 3448,
4.2], we can not perform step (3) of [RFC 3448, 4.3].  A clarification is
provided in [RFC 4342, sec. 5], which states that in these cases the nofeedback
timer (still) expires "after two seconds".

Many thanks to Ian McDonald for pointing this out and providing the
clarification.

The patch
  * implements [RFC 4342, sec. 5] with regard to the above case
  * consolidates handling timer restart by
	- adding an appropriate jump label and
	- initialising the timeout value
Acked-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This considers the  case - ACK received while no packet has been sent
so far. Resolved by printing a (rate-limited) warning message.

Further removes an unnecessary BUG_ON in ccid3_hc_tx_packet_recv,
received feedback on a terminating connection is simply ignored.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This patch removes a switch statement which is redundant since,
 * nothing is done in states TFRC_SSTATE_NO_SENT/TFRC_SSTATE_NO_FBACK
 * it is impossible that the function is called in the state TFRC_SSTATE_TERM, since
       --the function is called, in dccp_write_xmit, after ccid3_hc_tx_send_packet
       --if ccid3_hc_tx_send_packet is called in state TFRC_SSTATE_TERM, it returns
         -EINVAL, which means that ccid3_hc_tx_packet_sent will not be called
	 (compare dccp_write_xmit)
       --> therefore, this case is logically impossible
 * the remaining state is TFRC_SSTATE_FBACK which conditionally updates t_ipi, t_nom,
   and t_delta. This is a no-op, since
       --t_ipi only changes when feedback is received
       --however, when feedback arrives via ccid3_hc_tx_packet_recv, there is an identical
         code block which performs the same set of operations
       --performing the same set of operations again in ccid3_hc_tx_packet_sent therefore
         does not change anything, since between the time of receiving the last feedback
	 (and therefore update of t_ipi, t_nom, and t_delta), the value of t_ipi has not
	 changed
       --since t_ipi has not changed, the values of t_delta and t_nom also do not change,
         they depend fully on t_ipi
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This resolves an `XXX' in ccid3_hc_tx_send_packet().

The function is only called on Data and DataAck packets and returns a negative
result on zero-sized messages. This is a reasonable policy since CCID 3 is a
congestion-control module and congestion control on zero-sized Data(Ack)
packets is in a way pathological.

The patch uses a more suitable error code for this case, it returns the Posix.1
code `EBADMSG' ("Not a data message") instead of `ENOTCONN'.

As a result of ignoring zero-sized packets, a the condition for a warning
"First packet is data" in ccid3_hc_tx_packet_sent is always satisfied; this
message has been removed since it will always be printed.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This makes some logically equivalent simplifications, by replacing
rc - values plus goto's with direct return statements.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Problem:

This patch performs a simplifying (performance) optimisation:

 In each call of the inline function ccid3_calc_new_t_ipi(), the state is
 tested against TFRC_SSTATE_NO_FBACK. This is expensive when the function
 is called very often. A simpler solution, implemented by this patch, is
 to adapt the control flow.

Background:

Problem:

Now that we can stuff bigger ack vectors into options.
Signed-off-by: NAndrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Ack vectors grow proportional to the window size.  If an ack vector does not fit
into a single option, it must be spread across multiple options.  This patch
will allow for windows to grow larger.

Committer note: Simplified the patch a bit, original algorithm kept.
Signed-off-by: NAndrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Commiter note:

This was split from Andrea's original patch, in the process I changed the type
of the ackvec index fields to u16 instead of to int and haven't folded
dccp_ackvec_parse with dccp_ackvec_check_rcv_ackno.

Next patch will actually do the insertion of more than one ackvec per packet,
using, initially, up to a max of 2 ackvecs as per Andrea's original patch, then
I'll work on support for larger ackvecs, be it using a sysctl or using
setsockopt.
Signed-off-by: NAndrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Commiter note: original patch was splitted.
Signed-off-by: NAndrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This one got lost on the way from Ian to Gerrit to me, fix it.
Signed-off-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This removes a non-referenced variable.
Signed-off-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This makes the code of the dccp_probe module more portable.
Signed-off-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This adds documentation to the CCID 3 rx/tx socket fields, plus some
minor re-formatting.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This reaps the benefit of the earlier patch, which changed the type of
CCID 3 states to use enums, in that many conditions are now simplified
and the number of possible (unexpected) values is greatly reduced.

In a few instances, this also allowed to simplify pre-conditions; where
care has been taken to retain logical equivalence.

[DCCP]: Introduce a consistent BUG/WARN message scheme

This refines the existing set of DCCP messages so that
 * BUG(), BUG_ON(), WARN_ON() have meaningful DCCP-specific counterparts
 * DCCP_CRIT (for severe warnings) is not rate-limited
 * DCCP_WARN() is introduced as rate-limited wrapper

Using these allows a faster and cleaner transition to their original
counterparts once the code has matured into a full DCCP implementation.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Previously the transmit queue was unbounded.

This patch:
	* puts a limit on transmit queue length
	  and sends back EAGAIN if the buffer is full
	* sets the TX queue length to a sensible default
	* implements tx buffer sysctls for DCCP
Signed-off-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This adds a CCID3 debug option to the configuration menu
which is missing in Kconfig, but already used by the code.

CCID 2 already provides such an entry.

To enable debugging, set CONFIG_IP_DCCP_CCID3_DEBUG=y

NOTE: The use of ccid3_{t,r}x_state_name is safe, since
      now only enum values can appear.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This patch
  * makes debugging (when configured) work both for static / module build
  * provides generic debugging macros for use in other DCCP / CCID modules
  * adds missing information about debug parameters to Kconfig
  * performs some code tidy-up
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Code diff stats:

[acme@newtoy net-2.6.20]$ codiff /tmp/dccp.ko.before /tmp/dccp.ko.after
/pub/scm/linux/kernel/git/acme/net-2.6.20/net/dccp/feat.c:
  __dccp_feat_init      |  -16
  dccp_feat_change_recv |  -55
  dccp_feat_clone       |  -56
 3 functions changed, 127 bytes removed
[acme@newtoy net-2.6.20]$
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

These are code optimizations which are relevant when dealing with large
windows.  They are not coded the way I would like to, but they do the job for
the short-term.  This patch should be more neat.

Commiter note: Changed the seqno comparisions to use {after,before}48 to handle
               wrapping.
Signed-off-by: NAndrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Spotted by Ian McDonald, tentatively fixed by Gerrit Renker:

http://www.mail-archive.com/dccp%40vger.kernel.org/msg00599.html

Rewritten not to unroll sk_receive_skb, in the common case, i.e. no lock
debugging, its optimized away.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Spotted by Eric Dumazet in tcp_v4_rcv().
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This patch tackles the following problem:
       * the ccid3_hc_{t,r}x_sock define ccid3hc{t,r}x_state as `u8', but
         in reality there can only be a few, pre-defined enum names
       * this necessitates addiditional checking for unexpected values
         which would otherwise be caught by the compiler
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Based on implementation by Rick Payne.
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Do not traverse the list of ack vector records [proportional to window size]
when we know we will not find what we are looking for.  This is especially
useful because ack vectors are checked twice:
1) Upon parsing of options.
2) Upon notification of a new ack.

All of the work will occur during check #1.  Therefore, when check #2 is
performed, no new work will be done.  This is now "detected" and there is no
performance hit when doing #2.
Signed-off-by: NAndrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This patch does not change code; it performs some trivial clean/tidy-ups:

  * removal of a `debug_prefix' string in favour of the
    already existing dccp_role(sk)

  * add documentation of structures and constants

  * separated out the cases for invalid packets (step 1
    of the packet validation)

  * removing duplicate statements

  * combining declaration & initialisation
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This patch replaces cryptic feature negotiation messages of type

Oct 31 15:42:20 kernel: dccp_feat_change: feat change type=32 feat=1
Oct 31 15:42:21 kernel: dccp_feat_change: feat change type=34 feat=1
Oct 31 15:42:21 kernel: dccp_feat_change: feat change type=32 feat=5

into ones of type:

Nov  2 13:54:45 kernel: dccp_feat_change: ChangeL(CCID (1), 3)
Nov  2 13:54:45 kernel: dccp_feat_change: ChangeR(CCID (1), 3)
Nov  2 13:54:45 kernel: dccp_feat_change: ChangeL(Ack Ratio (5), 2)

Also,
	* completed the feature number list wrt RFC 4340 sec. 6.4
	* annotating which ones have been implemented so far
	* implemented rudimentary sanity checking in feat.c (FIXMEs)
	* some minor fixes

Commiter note: uninlined dccp_feat_name and dccp_feat_typename, for
               consistency with dccp_{state,packet}_name, that, BTW,
               should be compiled only if CONFIG_IP_DCCP_DEBUG is
               selected, leaving this to another cset tho. Also
               shortened dccp_feat_negotiation_debug to dccp_feat_debug.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Resolves the problem that if IPv6 was configured `y' and DCCP `m' then
dccp_ipv6 was not built as a module. With this change, dccp_ipv6 is built
as a module whenever DCCP *OR* IPv6 are configured as modules; it will be
built-in only if both DCCP = `y' and IPV6 = `y'.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Throughout the TCP/DCCP (and tunnelling) code, it often happens that the
return code of a transmit function needs to be tested against NET_XMIT_CN
which is a value that does not indicate a strict error condition.

This patch uses a macro for these recurring situations which is consistent
with the already existing macro net_xmit_errno, saving on duplicated code.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This
	* resolves a FIXME - DCCPv6 connections started all with
	  an initial sequence number of 1;
	* provides a redirection `secure_dccpv6_sequence_number'
	  in case the init_sequence_v6 code should be updated later;
	* concentrates the update of S.GAR into dccp_connect_init();
	* removes a duplicate dccp_update_gss() in ipv4.c;
	* uses inet->dport instead of usin->sin_port, due to the
	  following assignment in dccp_v4_connect():
 		inet->dport = usin->sin_port;
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This patch removes the following redundancies:

 1) The test skb->protocol == htons(ETH_P_IPV6) in dccp_v6_init_sequence
    is always true since
     * dccp_v6_conn_request() is the only calling function
     * dccp_v6_conn_request() redirects all skb's with ETH_P_IP to
       dccp_v4_conn_request()

 2) The first argument, `struct sock *sk', of dccp_v{4,6}_init_sequence()
    is never used.

(This is similar for tcp_v{4,6}_init_sequence, an analogous patch has been
 submitted to netdev and merged.)

By the way - are the `sport' / `dport' arguments in the right order?
I have made them consistent among calls but they seem to be in the
reverse order.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This removes 3 forward declarations by reordering 2 functions.

No code change at all.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

In order to make their function clearer and obtain a consistent naming
scheme to identify sysctls, all existing DCCP sysctls have been prefixed
with `sysctl_dccp', following the same convention as used by TCP.

Feature-specific sysctls retain the `feat' in the middle, although the
`default' has been dropped, since it is obvious from use.

Also removed a duplicate `dccp_feat_default_sequence_window' in ipv4.c.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>