This performs a minor optimisation: when ccid_hc_tx_send_packet
returns a value greater zero, then the same call previously was done
again at the begin of the while loop in dccp_wait_for_ccid.

This patch exploits the available information and schedule-timeouts
directly instead.

Documentation also added.
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@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This factors code common to dccp_v{4,6}_ctl_send_reset into a separate function,
and adds support for filling in the Data 1 ... Data 3 fields from RFC 4340, 5.6.

It is useful to have this separate, since the following Reset codes will always
be generated from the control socket rather than via dccp_send_reset:
 * Code 3, "No Connection", cf. 8.3.1;
 * Code 4, "Packet Error" (identification for Data 1 added);
 * Code 5, "Option Error" (identification for Data 1..3 added, will be used later);
 * Code 6, "Mandatory Error" (same as Option Error);
 * Code 7, "Connection Refused" (what on Earth is the difference to "No Connection"?);
 * Code 8, "Bad Service Code";
 * Code 9, "Too Busy";
 * Code 10, "Bad Init Cookie" (not used).

Code 0 is not recommended by the RFC, the following codes would be used in
dccp_send_reset() instead, since they all relate to an established DCCP connection:
 * Code 1, "Closed";
 * Code 2, "Aborted";
 * Code 11, "Aggression Penalty" (12.3).
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@ghostprotocols.net>

In this patch, duplicated code is removed for the case when a Reset packet is
sent from a connected socket. This code duplication is between dccp_make_reset
and dccp_transmit_skb, which already contained an (up to now entirely unused)
switch statement to fill in the reset code from the DCCP_SKB_CB.

The only thing that has been removed is the call to dst_clone(dst), since
the queue_xmit functions use sk_dst_cache anyway.

I wasn't sure which purpose inet_sk_rebuild_header served, so I left it in.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@ghostprotocols.net>

This adds a FIXME to signal that the function dccp_send_delayed_ack is nowhere
used in the entire DCCP/CCID code.

Using a delayed Ack timer is suggested in 11.3 of RFC 4340, but it has also
rather subtle implications for the Ack-Ratio-accounting.

CCID2 does not use this (maybe it should).

I think leaving the function in is good, in case someone wants to implement
this.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@ghostprotocols.net>

The parameter `seq' of dccp_send_sync() is in fact an acknowledgement number
and not a sequence number - thus renamed by this patch into `ackno'.

Secondly, a `critical' warning is added when a Sync/SyncAck could not be sent.

Sanity: I have checked all other functions that are called in dccp_transmit_skb,
        there are no clashes with the use of dccpd_ack_seq; no other function is
        using this slot at the same time.
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@ghostprotocols.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This adds more detail in the wait_for_ccid packet scheduling loop.
In particular, it informs about (i) when delay is used and (ii) why
a packet is discarded.
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@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The TX CCID needs the write_xmit_timer for delaying packet sends. Previously
this timer was only activated on active (connecting) sockets.

This patch initialises the write_xmit_timer in sync with the other timers, i.e.
the timer will be ready on any socket. This is used by applications with a
listening socket which start to stream after receiving an initiation by the
client.  The write_xmit_timer is stopped when the application closes, as before.

Was tested to work and to remove the timer bug reported on dccp@vger.

Also moved timer initialisation into timer.c (static). 
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Acked-by: NIan McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NPatrick McHardy <kaber@trash.net>
Acked-by: NPaul Moore <paul.moore@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

Revert 93173112

We can't elide the skb_set_owner_w() here because things like certain
netfilter targets (such as owner MATCH) need a socket to be set on the
SKB for correct operation.

Thanks to Jan Engelhardt and other netfilter list members for
pointing this out.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

That accumulated over the last months hackaton, shame on me for not
using git-apply whitespace helping hand, will do that from now on.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This adds a (debug) warning message which is triggered whenever a packet is
discarded due to send failure.

It also adds a conditional, so that an interruption during dccp_wait_for_ccid
is not treated as a `BUG': the rationale is that interruptions are external,
whereas bug warnings are concerned with the internals.
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>

It simplifies waiting for the CCID module to signal that a packet
is ready to be sent.  Other simplifications flow on from this such as
removing constants.

As a result of this EAGAIN is not returned any more by dccp_wait_for_ccid
(which would otherwise lead to unnecessarily discarding the packet in
dccp_write_xmit).
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 patch implements a suggestion by Ian McDonald and

 1) Avoids tests against negative packet lengths by using unsigned int
    for packet payload lengths in the CCID send_packet()/packet_sent() routines

 2) As a consequence, it removes an now unnecessary test with regard to `len > 0'
    in ccid3_hc_tx_packet_sent: that condition is always true, since
      * negative packet lengths are avoided
      * ccid3_hc_tx_send_packet flags an error whenever the payload length is 0.
        As a consequence, ccid3_hc_tx_packet_sent is never called as all errors
        returned by ccid_hc_tx_send_packet are caught in dccp_write_xmit

 3) Removes the third argument of ccid_hc_tx_send_packet (the `len' parameter),
    since it is currently always set to skb->len. The code is updated with regard
    to this parameter change.
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 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>

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>

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>

Problem:

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

This patch fixes data being spewed into the logs continually. As the
code stood if there was a large queue and long delays timeo would go
down to zero and never get reset.

This fixes it by resetting timeo. Put constant into header as well.
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 is a code simplification:
it combines three often recurring operations into one inline function,

        * allocate `len' bytes header space in skb
        * fill these `len' bytes with zeroes
        * cast the start of this header space as dccp_hdr
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

The data itself is already charged to the SKB, doing
the skb_set_owner_w() just generates a lot of noise and
extra atomics we don't really need.

Lmbench improvements on lat_tcp are minimal:

before:
TCP latency using localhost: 23.2701 microseconds
TCP latency using localhost: 23.1994 microseconds
TCP latency using localhost: 23.2257 microseconds

after:
TCP latency using localhost: 22.8380 microseconds
TCP latency using localhost: 22.9465 microseconds
TCP latency using localhost: 22.8462 microseconds
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This adds transmit buffering to DCCP.

I have tested with CCID2/3 and with loss and rate limiting.

Signed off by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

And not the silly LIMIT_NETDEBUG and silently return without inserting
the option requested.

Also drop some old debugging messages associated to option insertion.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Using this also provides opportunities for introducing
inet_csk_alloc_skb that would call alloc_skb, account it to the sock
and skb_reserve(max_header), but I'll leave this for later, for now
using sk_prot->max_header consistently is enough.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

With this patch in place we can break down the complexity by better
compartmentalizing the code that is common to ipv6 and ipv4.

Now we have these modules:
Module                  Size  Used by
dccp_diag               1344  0
inet_diag               9448  1 dccp_diag
dccp_ccid3             15856  0
dccp_tfrc_lib          12320  1 dccp_ccid3
dccp_ccid2              5764  0
dccp_ipv4              16996  2
dccp                   48208  4 dccp_diag,dccp_ccid3,dccp_ccid2,dccp_ipv4

dccp_ipv6 still requires dccp_ipv4 due to dccp_ipv6_mapped, that is
the next target to work on the "hey, ipv4 is legacy, I only want ipv6
dude!" direction.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

dccp_make_response is shared by ipv4/6 and the ipv6 code was
recalculating the checksum, not good, so move the dccp_v4_checksum
call to dccp_v4_send_response.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Renaming it to dccp_send_reset and moving it from the ipv4 specific
code to the core dccp code.

This fixes some bugs in IPV6 where timers would send v4 resets, etc.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Still needs more work, but boots and doesn't crashes, even
does some negotiation!

18:38:52.174934  127.0.0.1.43458 > 127.0.0.1.5001: request <change_l ack_ratio 2, change_r ccid 2, change_l ccid 2>
18:38:52.218526  127.0.0.1.5001 > 127.0.0.1.43458: response <nop, nop, change_l ack_ratio 2, confirm_r ccid 2 2, confirm_l ccid 2 2, confirm_r ack_ratio 2>
18:38:52.185398  127.0.0.1.43458 > 127.0.0.1.5001: <nop, confirm_r ack_ratio 2, ack_vector0 0x00, elapsed_time 212>

:-)
Signed-off-by: NAndrea Bittau <a.bittau@cs.ucl.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

To help in reducing the number of include dependencies, several files were
touched as they were getting needed headers indirectly for stuff they use.

Thanks also to Alan Menegotto for pointing out that net/dccp/proto.c had
linux/dccp.h include twice.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As DCCP needs to be called in the same spots.

Now we have a member in inet_sock (is_icsk), set at sock creation time from
struct inet_protosw->flags (if INET_PROTOSW_ICSK is set, like for TCP and
DCCP) to see if a struct sock instance is a inet_connection_sock for places
like the ones in ip_sockglue.c (v4 and v6) where we previously were looking if
sk_type was SOCK_STREAM, that is insufficient because we now use the same code
for DCCP, that has sk_type SOCK_DCCP.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Basically exports a similar set of functions as the one exported by
the non-AF specific TCP code.

In the process moved some non-AF specific code from dccp_v4_connect to
dccp_connect_init and moved the checksum verification from
dccp_invalid_packet to dccp_v4_rcv, so as to use it in dccp_v6_rcv
too.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

And make the core DCCP code AF agnostic, just like TCP, now its time
to work on net/dccp/ipv6.c, we are close to the end!
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

  
Here is a complimentary insurance policy for those feeling a bit insecure.
You don't have to accept this.  However, if you do, you can't blame me for
it :)
  
> 1) dccp_transmit_skb sets the owner for all packets except data packets.
  
We can actually verify this by looking at pkt_type.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

  
While we're at it let's reorganise the set_owner_w calls a little so that:
  
1) dccp_transmit_skb sets the owner for all packets except data packets.
2) Add dccp_skb_entail to set owner for packets queued for retransmission.
3) Make dccp_transmit_skb static.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Turns out the problem has nothing to do with use-after-free or double-free.
It's just that we're not clearing the CB area and DCCP unlike TCP uses a CB
format that's incompatible with IP.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NIan McDonald <imcdnzl@gmail.com>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>