This updates program documentation: spell out precise conditions about
which packets are eligible for retransmission (which is actually quite
hard to extract from RFC 4340).

It is based on the following table derived from RFC 4340:

+-----------+---------------------------------+---------------------+
|   Type    | Retransmit?                     |  Remark             |
+-----------+---------------------------------+---------------------+
| Request   |  in client-REQUEST state        | sec. 8.1.1          |
| Response  |  NEVER                          | SHOULD NOT, 8.1.3   |
| Data      |  NEVER                          | unreliable protocol |
| Ack       |  possible in client-PARTOPEN    | sec. 8.1.5          |
| DataAck   |  NEVER                          | unreliable protocol |
| CloseReq  |  only in server-CLOSEREQ state  | MUST, sec. 8.3      |
| Close     |  in node-CLOSING state          | MUST, sec. 8.3      |
+-----------+-------------------------------------------------------+
| Reset     |  only in response to other packets                    |
| Sync      |  only in response to sequence-invalid packets (7.5.4) |
| SyncAck   |  only in response to Sync packets                     |
+-----------+-------------------------------------------------------+

Hence the only packets eligible for retransmission are:
       * Requests in client-REQUEST  state (sec. 8.1.1)
       * Acks     in client-PARTOPEN state (sec. 8.1.5)
       * CloseReq in server-CLOSEREQ state (sec. 8.3)
       * Close    in   node-CLOSING  state (sec. 8.3)

I had meant to put in a check for these types too, but have left that
for later.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

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

Based upon a patch by Joe Perches.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Only change upper-layer checksum from 0 to 0xFFFF for UDP (as RFC 768
states), not for others as RFC 4443 doesn't require it.
Signed-off-by: NBrian Haley <brian.haley@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Noticed by Al Viro:
     (frh->tos & ~IPV6_FLOWINFO_MASK))
where IPV6_FLOWINFO_MASK is htonl(0xfffffff) and frh->tos
is u8, which makes no sense here...
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Account for the netlink message header size directly in nlmsg_new()
instead of relying on the caller calculate it correctly.

Replaces error handling of message construction functions when
constructing notifications with bug traps since a failure implies
a bug in calculating the size of the skb.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Acked-by: NPaul Moore <paul.moore@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This removes two redundancies:

1) The test (skb->protocol == htons(ETH_P_IPV6) in tcp_v6_init_sequence()
   is always true, due to
	* tcp_v6_conn_request() is the only function calling this one
	* tcp_v6_conn_request() redirects all skb's with ETH_P_IP protocol to
	  tcp_v4_conn_request() [ cf. top of tcp_v6_conn_request()]

2) The first argument, `struct sock *sk' of tcp_v{4,6}_init_sequence() is
   never used.
Signed-off-by: NGerrit Renker  <gerrit@erg.abdn.ac.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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>

For IP MIB (RFC4293).
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

Otherwise, we will see a lot of casts...
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

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 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>

Fixes a typo in Kconfig, patch is by Ian McDonald and is re-sent from
http://www.mail-archive.com/dccp@vger.kernel.org/msg00579.htmlSigned-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 does the same for ipv6.c as the preceding one does for ipv4.c: Only the
inet_connection_sock_af_ops forward declarations remain, since at least
dccp_ipv6_mapped has a circular dependency to dccp_v6_request_recv_sock.

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

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:

Gerrit Renker noticed dccp_tw_deschedule and submitted a patch with a FIXME,
but as he suggests in the same patch the best thing is to just ditch this
declaration, while doing that also noticed that tcp_tw_count is as well not
defined anywhere, so ditch it too.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

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>

This refers to the possible memory leak pointed out in
http://www.mail-archive.com/dccp@vger.kernel.org/msg00574.html,
fixed by David Miller in
http://www.mail-archive.com/netdev@vger.kernel.org/msg24881.html

and adds a FIXME to point out where code is missing.
Signed-off-by: NGerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>

This is a re-send from
http://www.mail-archive.com/dccp@vger.kernel.org/msg00553.html

It is the same patch as before, but I have built in Arnaldo's suggestions
pointed out in that posting.
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>

Rearrange TCP entries in alpha order.
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If user has permision to load modules, then autoload then attempt
autoload of TCP congestion module.
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Allow normal users to only choose among a restricted set of congestion
control choices.  The default is reno and what ever has been configured
as default. But the policy can be changed by administrator at any time.

For example, to allow any choice:
    cp /proc/sys/net/ipv4/tcp_available_congestion_control \
       /proc/sys/net/ipv4/tcp_allowed_congestion_control
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Create /proc/sys/net/ipv4/tcp_available_congestion_control
that reflects currently available TCP choices.
Signed-off-by: NStephen Hemminger <shemminger@osdl.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

An alternate solution would be to make the digest a pointer, allocate
it in sctp_endpoint_init() and free it in sctp_endpoint_destroy().

I guess I should have originally done it this way...

  CC [M]  net/sctp/sm_make_chunk.o
net/sctp/sm_make_chunk.c: In function 'sctp_unpack_cookie':
net/sctp/sm_make_chunk.c:1358: warning: initialization discards qualifiers from pointer target type

The reason is that sctp_unpack_cookie() takes a const struct
sctp_endpoint and modifies the digest in it (digest being embedded in
the struct, not a pointer).  Make digest a pointer to fix this
warning.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Acked-by: NSridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

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>

Based on patch by Patrick McHardy.

Add a new option, NET_SCH_FIFO, which provides a simple fifo qdisc
without requiring CONFIG_NET_SCHED.

The d80211 stack needs a generic fifo qdisc for WME.  At present it
uses net/d80211/fifo_qdisc.c which is functionally equivalent to
sch_fifo.c.  This patch will allow the d80211 stack to remove
net/d80211/fifo_qdisc.c and use sch_fifo.c instead.
Signed-off-by: NDavid Kimdon <david.kimdon@devicescape.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduces a new flag FIB_RULE_INVERT causing rules to apply
if the specified selector doesn't match.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move the attribute policy for the non-specific attributes into
net/fib_rules.h and include it in the respective protocols.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move mark selector currently implemented per protocol into
the protocol independant part.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For the sake of consistency.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that all protocols have been made aware of the mark
field it can be moved out of the union thus simplyfing
its usage.

The config options in the IPv4/IPv6/DECnet subsystems
to enable respectively disable mark based routing only
obfuscate the code with ifdefs, the cost for the
additional comparison in the flow key is insignificant,
and most distributions have all these options enabled
by default anyway. Therefore it makes sense to remove
the config options and enable mark based routing by
default.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

nfmark is being used in various subsystems and has become
the defacto mark field for all kinds of packets. Therefore
it makes sense to rename it to `mark' and remove the
dependency on CONFIG_NETFILTER.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>