This fixes two bugs in processing of connection-Requests in
v{4,6}_conn_request:

 1. Due to using the variable `reset_code', the Reset code generated
    internally by dccp_parse_options() is overwritten with the
    initialised value ("Too Busy") of reset_code, which is not what is
    intended.

 2. When receiving a connection-Request on a multicast or broadcast
    address, no Reset should be generated, to avoid storms of such
    packets. Instead of jumping to the `drop' label, the
    v{4,6}_conn_request functions now return 0. Below is why in my
    understanding this is correct:

    When the conn_request function returns < 0, then the caller,
    dccp_rcv_state_process(), returns 1. In all instances where
    dccp_rcv_state_process is called (dccp_v4_do_rcv, dccp_v6_do_rcv,
    and dccp_child_process), a return value of != 0 from
    dccp_rcv_state_process() means that a Reset is generated.

    If on the other hand the conn_request function returns 0, the
    packet is discarded and no Reset is generated.

Note: There may be a related problem when sending the Response, due to
the following.

	if (dccp_v6_send_response(sk, req, NULL))
		goto drop_and_free;
	/* ... */
	drop_and_free:
		return -1;

In this case, if send_response fails due to transmission errors, the
next thing that is generated is a Reset with a code "Too Busy". I
haven't been able to conjure up such a condition, but it might be good
to change the behaviour here also (not done by this patch).
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>

This replaces normal addition with mod-48 addition so that sequence number
wraparound is respected.
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>

This trivial patch removes the unneeded pointer newdp, which is never used.
Signed-off-by: NMicah Gruber <micah.gruber@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.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>

Do this even for non-blocking sockets.  This avoids the silly -EAGAIN
that applications can see now, even for non-blocking sockets in some
cases (f.e. connect()).

With help from Venkat Tekkirala.
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 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>

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>

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>

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>

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>

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>

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>

Sorts out the comments for processing steps 2,3 in section 8.5 of RFC 4340.
All comments have been updated against this document, and the reference to step
2 has been made consistent throughout the files.
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 to remove reduplicated code
by concentrating and abstracting shared code.

Detailed Changes:

This relates to Arnaldo's announcement in
http://www.mail-archive.com/dccp@vger.kernel.org/msg00604.html

Originally this had been part of the Oops fix and is a revised variant of
http://www.mail-archive.com/dccp@vger.kernel.org/msg00598.html

No code change, merely reshuffling, with the particular objective of
having all request_sock_ops close(r) together for more clarity.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This patch removes two functions, the send_ack functions of request_sock,
which are not called/used by the DCCP code. It is correct that these
functions are not called, below is a justification why calling these
functions (on a passive socket in the LISTEN/RESPOND state) would mean
a DCCP protocol violation.

A) Background: using request_sock in TCP:

This is a code simplification and was singled out from the
DCCPv6 Oops patch on
http://www.mail-archive.com/dccp@vger.kernel.org/msg00600.html

It mainly makes the code consistent between ipv{4,6}.c for the functions
        dccp_v4_rcv
        dccp_v6_rcv
and removes the do_time_wait label to simplify code somewhat.

Commiter note: fixed up a compile problem, trivial.
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>

Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We currently allocate a fixed size (TCP_SYNQ_HSIZE=512) slots hash table for
each LISTEN socket, regardless of various parameters (listen backlog for
example)

On x86_64, this means order-1 allocations (might fail), even for 'small'
sockets, expecting few connections. On the contrary, a huge server wanting a
backlog of 50000 is slowed down a bit because of this fixed limit.

This patch makes the sizing of listen hash table a dynamic parameter,
depending of :
- net.core.somaxconn tunable (default is 128)
- net.ipv4.tcp_max_syn_backlog tunable (default : 256, 1024 or 128)
- backlog value given by user application  (2nd parameter of listen())

For large allocations (bigger than PAGE_SIZE), we use vmalloc() instead of
kmalloc().

We still limit memory allocation with the two existing tunables (somaxconn &
tcp_max_syn_backlog). So for standard setups, this patch actually reduce RAM
usage.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Updates the references to spec documents throughout the code, taking into
account that

* the DCCP, CCID 2, and CCID 3 drafts all became RFCs in March this year

* RFC 1063 was obsoleted by RFC 1191

* draft-ietf-tcpimpl-pmtud-0x.txt was published as an Informational
  RFC, RFC 2923 on 2000-09-22.

All references verified.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I think I got the cause for the Oops observed in
http://www.mail-archive.com/dccp@vger.kernel.org/msg00578.html

The problem is always with applications listening on PF_INET6 sockets. Apart
from the mentioned oops, I observed another one one, triggered at irregular
intervals via timer interrupt:

    run_timer_softirq -> dccp_keepalive_timer
                      -> inet_csk_reqsk_queue_prune
                      -> reqsk_free
                      -> dccp_v6_reqsk_destructor

The latter function is the problem and is also the last function to be called
in said kernel panic.

In any case, there is a real problem with allocating the right request_sock
which is what this patch tackles.

It fixes the following problem:
 - application listens on PF_INET6
 - DCCPv4 packet comes in, is handed over to dccp_v4_do_rcv, from there
   to dccp_v4_conn_request

Now: socket is PF_INET6, packet is IPv4. The following code then furnishes the
connection with IPv6 - request_sock operations:

   req = reqsk_alloc(sk->sk_prot->rsk_prot);

The first problem is that all further incoming packets will get a Reset since
the connection can not be looked up.

The second problem is worse:
 --> reqsk_alloc is called instead of inet6_reqsk_alloc
 --> consequently inet6_rsk_offset is never set (dangling pointer)
 --> the request_sock_ops are nevertheless still dccp6_request_ops
 --> destructor is called via reqsk_free
 --> dccp_v6_reqsk_destructor tries to free random memory location (inet6_rsk_offset not set)
 --> panic

I have tested this for a while, DCCP sockets are now handled correctly in all
three scenarios (v4/v6 only/v4-mapped).

Commiter note: I've added the dccp_request_sock_ops forward declaration to keep
               the tree building and to reduce the size of the patch for 2.6.19,
               later I'll move the functions to the top of the affected source
               code to match what we have in the TCP counterpart, where this
               problem hasn't existed in the first place, dumb me not to have
               done the same thing on DCCP land 8)
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

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

annotated address arguments (port number left alone for now); ditto
for inferred net-endian variables in callers.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

Right now most inet_lookup_* functions take a host-order hnum instead
of a network-order dport because that's how it is represented
internally.

This means that users of these functions have to be careful about
using the right byte-order.  To add more confusion, inet_lookup takes
a network-order dport unlike all other functions.

So this patch changes all visible inet_lookup functions to take a
dport and move all dport->hnum conversion inside them.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This automatically labels the TCP, Unix stream, and dccp child sockets
as well as openreqs to be at the same MLS level as the peer. This will
result in the selection of appropriately labeled IPSec Security
Associations.

This also uses the sock's sid (as opposed to the isec sid) in SELinux
enforcement of secmark in rcv_skb and postroute_last hooks.
Signed-off-by: NVenkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This labels the flows that could utilize IPSec xfrms at the points the
flows are defined so that IPSec policy and SAs at the right label can
be used.

The following protos are currently not handled, but they should
continue to be able to use single-labeled IPSec like they currently
do.

ipmr
ip_gre
ipip
igmp
sit
sctp
ip6_tunnel (IPv6 over IPv6 tunnel device)
decnet
Signed-off-by: NVenkat Yekkirala <vyekkirala@TrustedCS.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When using the default sequence window size (100) I got the following in
my logs:

Jun 22 14:24:09 localhost kernel: [ 1492.114775] DCCP: Step 6 failed for
DATA packet, (LSWL(6279674225) <= P.seqno(6279674749) <=
S.SWH(6279674324)) and (P.ackno doesn't exist or LAWL(18798206530) <=
P.ackno(1125899906842620) <= S.AWH(18798206548), sending SYNC...
Jun 22 14:24:09 localhost kernel: [ 1492.115147] DCCP: Step 6 failed for
DATA packet, (LSWL(6279674225) <= P.seqno(6279674750) <=
S.SWH(6279674324)) and (P.ackno doesn't exist or LAWL(18798206530) <=
P.ackno(1125899906842620) <= S.AWH(18798206549), sending SYNC...

I went to alter the default sysctl and it didn't take for new sockets.
Below patch fixes this.

I think the default is too low but it is what the DCCP spec specifies.

As a side effect of this my rx speed using iperf goes from about 2.8 Mbits/sec
to 3.5. This is still far too slow but it is a step in the right direction.

Compile tested only for IPv6 but not particularly complex change.

Signed off by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
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>

we dont free req if we cant parse the options.
This fixes coverity bug id #1046
Signed-off-by: NEric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

No code changes, just tidying up, in some cases moving EXPORT_SYMBOLs
to just after the function exported, etc.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>