16432 Commits

Author SHA1 Message Date
Jerry Chu
dca43c75e7 tcp: Add TCP_USER_TIMEOUT socket option.
This patch provides a "user timeout" support as described in RFC793. The
socket option is also needed for the the local half of RFC5482 "TCP User
Timeout Option".

TCP_USER_TIMEOUT is a TCP level socket option that takes an unsigned int,
when > 0, to specify the maximum amount of time in ms that transmitted
data may remain unacknowledged before TCP will forcefully close the
corresponding connection and return ETIMEDOUT to the application. If
0 is given, TCP will continue to use the system default.

Increasing the user timeouts allows a TCP connection to survive extended
periods without end-to-end connectivity. Decreasing the user timeouts
allows applications to "fail fast" if so desired. Otherwise it may take
upto 20 minutes with the current system defaults in a normal WAN
environment.

The socket option can be made during any state of a TCP connection, but
is only effective during the synchronized states of a connection
(ESTABLISHED, FIN-WAIT-1, FIN-WAIT-2, CLOSE-WAIT, CLOSING, or LAST-ACK).
Moreover, when used with the TCP keepalive (SO_KEEPALIVE) option,
TCP_USER_TIMEOUT will overtake keepalive to determine when to close a
connection due to keepalive failure.

The option does not change in anyway when TCP retransmits a packet, nor
when a keepalive probe will be sent.

This option, like many others, will be inherited by an acceptor from its
listener.

Signed-off-by: H.K. Jerry Chu <hkchu@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-30 13:23:33 -07:00
Stephen Rothwell
2c70b51962 IPVS: include net/ip6_checksum.h for csum_ipv6_magic
Fixes this build error:

net/netfilter/ipvs/ip_vs_core.c: In function 'ip_vs_nat_icmp_v6':
net/netfilter/ipvs/ip_vs_core.c:640: error: implicit declaration of function 'csum_ipv6_magic'

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-29 21:15:26 -07:00
Akinobu Mita
6a499b242f phonet: use for_each_set_bit
Replace open-coded loop with for_each_set_bit().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-28 15:37:04 -07:00
Akinobu Mita
762c29164e econet: kill unnecessary spin_lock_init()
The spinlock aun_queue_lock is initialized statically. It is unnecessary
to initialize by spin_lock_init() at module load time.

This is detected by the semantic patch.

// <smpl>
@def@
declarer name DEFINE_SPINLOCK;
identifier spinlock;
@@

DEFINE_SPINLOCK(spinlock);

@@
identifier def.spinlock;
@@

- spin_lock_init(&spinlock);
// </smpl>

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Julia Lawall <julia@diku.dk>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-28 15:37:03 -07:00
Johannes Berg
5b714c6a37 mac80211: fix offchannel queue stop
Somebody noticed this problem, and I outlined
to them how to fix it, but haven't heard back
from them. So while I was adding the state
field I figured I could use it to fix it.

The problem, as I understand it, is that when
we go offchannel while the driver has a queue
stopped, the driver will likely start draining
the queue and then enable it while offchannel.
This in turn will enable the interface queue,
and that leads to transmitting data frames on
the wrong channel.

Fix this by keeping track of offchannel status
per interface, and not enabling the interface
queues on interfaces that are offchannel when
the driver enables a queue.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:53:31 -04:00
Johannes Berg
34d4bc4d41 mac80211: support runtime interface type changes
Add support to mac80211 for changing the interface
type even when the interface is UP, if the driver
supports it.

To achieve this
 * add a new driver callback for switching,
 * split some of the interface up/down code out
   into new functions (do_open/do_stop), and
 * maintain an own __SDATA_RUNNING bit that will
   not be set during interface type, so that any
   other code doesn't use the interface.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:53:31 -04:00
Johannes Berg
87490f6db3 mac80211: split out concurrent vif checks
Split the concurrent virtual interface checks
into a new function that can be used to check
for any given new interface type.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:53:31 -04:00
Johannes Berg
bf533e0bfd mac80211: simplify zero address checks
The libertas_tf special code for zero addresses
is a bit too complex, it compares against a stack
value instead of using is_zero_ether_addr() and
tries to update all interfaces even if just the
one that's being brought up needs to be changed.
Additionally, the repeated check for a valid MAC
address need only be done if we actually changed
it on the fly.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:53:30 -04:00
Johannes Berg
26a58456be mac80211: switch to ieee80211_sdata_running
Since the introduction of ieee80211_sdata_running(),
some new code was introduced that uses netif_running()
instead. Switch all these instances over.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:53:30 -04:00
Johannes Berg
b9dcf712d1 mac80211: clean up ifdown/cleanup paths
There's a lot of redundant code in mac80211's
interface cleanup/down, for example freeing
AP beacons is done both when the interface is
set DOWN as well as when it is torn down, of
which only the former has any effect.

Also, a bunch of things should be closer to
where they matter, like the MLME timers that
we should cancel when disassociating, rather
than only when the interface is set DOWN.

Clean up all this code.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:53:30 -04:00
Johannes Berg
2337db8db8 mac80211: use subqueue helpers
There are subqueue helpers so that we don't
need to get the TX queue and then wake/stop
it, use those helpers.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:27:08 -04:00
Johannes Berg
a621fa4d6a mac80211: allow changing port control protocol
Some vendor specified mechanisms for 802.1X-style
functionality use a different protocol than EAP
(even if EAP is vendor-extensible). Support this
in mac80211 via the cfg80211 API for it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:27:07 -04:00
Johannes Berg
c0692b8fe2 cfg80211: allow changing port control protocol
Some vendor specified mechanisms for 802.1X-style
functionality use a different protocol than EAP
(even if EAP is vendor-extensible). Allow setting
the ethertype for the protocol when a driver has
support for this. The default if unspecified is
EAP, of course.

Note: This is suitable only for station mode, not
      for AP implementation.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:27:07 -04:00
Johannes Berg
3ffc2a905b mac80211: allow vendor specific cipher suites
Allow drivers to specify their own set of cipher
suites to advertise vendor-specific ciphers. The
driver is then required to implement hardware
crypto offload for it.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:27:07 -04:00
Johannes Berg
7d64b7cc1f cfg80211: allow vendor specific cipher suites
cfg80211 currently rejects all cipher suites it
doesn't know about for key length checking
purposes. This can lead to inconsistencies when
a driver advertises an algorithm that cfg80211
doesn't know about. Remove this rejection so
drivers can specify any algorithm they like.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:27:07 -04:00
Johannes Berg
8789d459bc mac80211: allow scan to complete from any context
The ieee80211_scan_completed() function was a frequent
source of potential deadlocks, since it is called by
drivers but may call back into drivers, so drivers had
to make sure to call it without any locks held, which
frequently lead to more complex code in drivers. Avoid
that problem by allowing the function to be called in
any context, and queueing the actual work it does.
Also update the documentation for it to indicate this.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:27:06 -04:00
Johannes Berg
5f33c92d18 mac80211: remove unused scan expire define
Since cfg80211 manages the BSS list completely,
this define hasn't been used for a long time
and will never be used again.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-27 13:27:06 -04:00
Eric Dumazet
40d0802b3e gro: __napi_gro_receive() optimizations
compare_ether_header() can have a special implementation on 64 bit
arches if CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS is defined.

__napi_gro_receive() and vlan_gro_common() can avoid a conditional
branch to perform device match.

On x86_64, __napi_gro_receive() has now 38 instructions instead of 53

As gcc-4.4.3 still choose to not inline it, add inline keyword to this
performance critical function.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-26 22:03:08 -07:00
Changli Gao
53f91dc1f7 net: use scnprintf() to avoid potential buffer overflow
strlcpy() returns the total length of the string they tried to create, so
we should not use its return value without any check. scnprintf() returns
the number of characters written into @buf not including the trailing '\0',
so use it instead here.

Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-26 14:11:49 -07:00
Joe Perches
145ce502e4 net/sctp: Use pr_fmt and pr_<level>
Change SCTP_DEBUG_PRINTK and SCTP_DEBUG_PRINTK_IPADDR to
use do { print } while (0) guards.
Add SCTP_DEBUG_PRINTK_CONT to fix errors in log when
lines were continued.
Add #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
Add a missing newline in "Failed bind hash alloc"

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-26 14:11:48 -07:00
Simon Horman
dee06e4702 ipvs: switch to GFP_KERNEL allocations
Switch from GFP_ATOMIC allocations to GFP_KERNEL ones in
ip_vs_add_service() and ip_vs_new_dest(), as we hold a mutex and are
allowed to sleep in this context.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-26 13:21:29 -07:00
Simon Horman
4f72816ef0 IPVS: convert __ip_vs_securetcp_lock to a spinlock
Also rename __ip_vs_securetcp_lock to ip_vs_securetcp_lock.

Spinlock conversion was suggested by Eric Dumazet.

Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-26 13:21:29 -07:00
Simon Horman
bd14455048 IPVS: convert __ip_vs_sched_lock to a spinlock
Also rename __ip_vs_sched_lock to ip_vs_sched_lock.

Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-26 13:21:28 -07:00
Simon Horman
8870f8427b IPVS: ICMPv6 checksum calculation
Cc: Xiaoyu Du <tingsrain@gmail.com>
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-26 13:21:26 -07:00
stephen hemminger
aa7c6e5fa0 bridge: avoid ethtool on non running interface
If bridge port is offline, don't call ethtool to query speed.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-25 16:36:51 -07:00
Stephen Hemminger
944c794d64 bridge: fix locking comment
The carrier check is not called from work queue in current code.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-25 16:36:50 -07:00
Julia Lawall
b2aff96327 net/netfilter/ipvs: Eliminate memory leak
__ip_vs_service_get and __ip_vs_svc_fwm_get increment a reference count, so
that reference count should be decremented before leaving the function in an
error case.

A simplified version of the semantic match that finds this problem is:
(http://coccinelle.lip6.fr/)

// <smpl>
@r exists@
local idexpression x;
expression E;
identifier f1;
iterator I;
@@

x = __ip_vs_service_get(...);
<... when != x
     when != true (x == NULL || ...)
     when != if (...) { <+...x...+> }
     when != I (...) { <+...x...+> }
(
 x == NULL
|
 x == E
|
 x->f1
)
...>
* return ...;
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-25 16:36:50 -07:00
John W. Linville
e569aa78ba Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6 into for-davem
Conflicts:
	drivers/net/wireless/libertas/if_sdio.c
2010-08-25 14:51:42 -04:00
Johannes Berg
5eb5a52da6 mac80211: fix mesh advertisement
When a mac80211-based driver advertises mesh mode
support, this will be advertised to userspace.
However, if mac80211 was compiled without mesh
support, then that won't actually be true. Fix
this by removing the bit for mesh if mesh isn't
compiled in.

Since this synchronizes what we advertise to
cfg80211 and actually support, it means we can
now rely on cfg80211's interface type checks
and need not check again in mac80211.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-25 14:34:56 -04:00
Christian Lamparter
2c15a0cf27 mac80211: fix rcu-unsafe pointer dereference
This patch fixes a potential crash (null-pointer de-
reference) which was introduced in my previous patch:
 "mac80211: AMPDU rx reorder timeout timer"

During a BA teardown, the pointer to the soon-to-be-gone
tid_ampdu_rx element will be nullified. Therefore the
release timer mechanism has to be careful not to
accidentally access the item without any RCU protection.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-25 14:34:56 -04:00
Johannes Berg
74b70a4e38 nl80211: fix missing nesting
commit 95a6ccbb46c70cff376684c752831c014c87029d
Author: Johannes Berg <johannes.berg@intel.com>
Date:   Thu Aug 12 15:38:38 2010 +0200

    cfg80211/mac80211: extensible frame processing

introduced a netlink bug that caused parsing errors
in userspace because it forgot to close a nesting,
which would advertise a nesting length of zero to
userspace, which then completely threw off parsing
and led to

	Illegal nla->nla_type == 0

being printed by libnl.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-25 14:34:56 -04:00
Christian Lamparter
258086a48b mac80211: cancel restart_work in ieee80211_unregister_hw
Unlike most other workqueue-tasks, the restart_work is
not scheduled onto mac80211's private per-interface
workqueue, but onto one of the system-wide workqueues.

Therefore the mac80211-stack has to cancel any pending
restarts, before destroying the shared device context
and handing back the memory. Otherwise - under very
unlucky circumstances - there could be a stale work-
item left, because some other kernel component might
have delayed the execution of ieee80211_restart_work
for too long.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-25 14:33:20 -04:00
Wey-Yi Guy
ff67bb86d4 mac80211: fix warning for un-used parameter
mesh_hdr only used when CONFIG_MAC80211_MESH is defined

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-25 14:33:17 -04:00
Joe Perches
0fb9a9ec27 net/mac80211: Use wiphy_<level>
Standardize logging messages from
	printk(KERN_<level> "%s: " fmt , wiphy_name(foo), args);
to
	wiphy_<level>(foo, fmt, args);

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-25 14:33:17 -04:00
Stephen Hemminger
c2e3143e3c tc: add meta match on receive hash
Trivial extension to existing meta data match rules to allow
matching on skb receive hash value.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-24 14:48:10 -07:00
Eric Dumazet
ec550d246e net: ip_append_data() optim
Compiler is not smart enough to avoid a conditional branch.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-24 14:45:09 -07:00
Johannes Berg
2e161f78e5 cfg80211/mac80211: extensible frame processing
Allow userspace to register for more than just
action frames by giving the frame subtype, and
make it possible to use this in various modes
as well.

With some tweaks and some added functionality
this will, in the future, also be usable in AP
mode and be able to replace the cooked monitor
interface currently used in that case.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-24 16:27:56 -04:00
Johannes Berg
ac4c977d16 mac80211: remove unused don't-encrypt flag
When MFP is disabled, action frames will not
be encrypted since they are management frames
and the only management frames that can then
be encrypted are authentication frames.

Therefore, setting the don't-encrypt flag on
action frames is unnecessary.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-24 16:27:55 -04:00
Johannes Berg
633adf1ad1 cfg80211: mark ieee80211_hdrlen const
This function analyses only its single, value-passed
argument, and has no side effects. Thus it can be
const, which makes mac80211 smaller, for example:

   text	   data	    bss	    dec	    hex	filename
 362518	  16720	    884	 380122	  5ccda	mac80211.ko (before)
 362358	  16720	    884	 379962	  5cc3a	mac80211.ko (after)

a 160 byte saving in text size, and an optimisation
because the function won't be called as often.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-08-24 16:27:54 -04:00
stephen hemminger
0fdc100bdc ethtool: allow non-netadmin to query settings
The SNMP daemon uses ethtool to determine the speed of
network interfaces. This fails on Debian (and probably elsewhere)
because for security SNMP daemon runs as non-root user (snmp).

Note: A similar patch was rejected previously because of a concern about
the possibility that on some hardware querying the ethtool settings
requires access to the PHY and could slow the machine down.  But the
security risk of requiring SNMP daemon (and related services)
to run as root far out weighs the risk of denial-of-service.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23 20:43:16 -07:00
Eric Dumazet
afdcba371f net: copy_rtnl_link_stats64() simplification
No need to use a temporary struct rtnl_link_stats64 variable,
just copy the source to skb buffer.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23 20:43:16 -07:00
Changli Gao
0eec32ff35 net_sched: act_csum: coding style cleanup
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23 20:43:15 -07:00
David S. Miller
7abac68602 pkt_sched: Make act_csum depend upon INET.
It uses ip_send_check() and stuff like that.

Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23 20:42:11 -07:00
Gerrit Renker
231cc2aaf1 dccp ccid-2: Replace broken RTT estimator with better algorithm
The current CCID-2 RTT estimator code is in parts broken and lags behind the
suggestions in RFC2988 of using scaled variants for SRTT/RTTVAR.

That code is replaced by the present patch, which reuses the Linux TCP RTT
estimator code.

Further details:
----------------
 1. The minimum RTO of previously one second has been replaced with TCP's, since
    RFC4341, sec. 5 says that the minimum of 1 sec. (suggested in RFC2988, 2.4)
    is not necessary. Instead, the TCP_RTO_MIN is used, which agrees with DCCP's
    concept of a default RTT (RFC 4340, 3.4).
 2. The maximum RTO has been set to DCCP_RTO_MAX (64 sec), which agrees with
    RFC2988, (2.5).
 3. De-inlined the function ccid2_new_ack().
 4. Added a FIXME: the RTT is sampled several times per Ack Vector, which will
    give the wrong estimate. It should be replaced with one sample per Ack.
    However, at the moment this can not be resolved easily, since
    - it depends on TX history code (which also needs some work),
    - the cleanest solution is not to use the `sent' time at all (saves 4 bytes
      per entry) and use DCCP timestamps / elapsed time to estimated the RTT,
      which however is non-trivial to get right (but needs to be done).

Reasons for reusing the Linux TCP estimator algorithm:
------------------------------------------------------
Some time was spent to find a better alternative, using basic RFC2988 as a first
step. Further analysis and experimentation showed that the Linux TCP RTO
estimator is superior to a basic RFC2988 implementation. A summary is on
http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/ccid2/rto_estimator/

In addition, this estimator fared well in a recent empirical evaluation:

    Rewaskar, Sushant, Jasleen Kaur and F. Donelson Smith.
    A Performance Study of Loss Detection/Recovery in Real-world TCP
    Implementations. Proceedings of 15th IEEE International
    Conference on Network Protocols (ICNP-07), 2007.

Thus there is significant benefit in reusing the existing TCP code.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23 20:13:31 -07:00
Gerrit Renker
c38c92a84a dccp ccid-2: Simplify dec_pipe and rearming of RTO timer
This removes the dec_pipe function and improves the way the RTO timer is rearmed
when a new acknowledgment comes in.

Details and justification for removal:
--------------------------------------
 1) The BUG_ON in dec_pipe is never triggered: pipe is only decremented for TX
    history entries between tail and head, for which it had previously been
    incremented in tx_packet_sent; and it is not decremented twice for the same
    entry, since it is
    - either decremented when a corresponding Ack Vector cell in state 0 or 1
      was received (and then ccid2s_acked==1),
    - or it is decremented when ccid2s_acked==0, as part of the loss detection
      in tx_packet_recv (and hence it can not have been decremented earlier).

 2) Restarting the RTO timer happens for every single entry in each Ack Vector
    parsed by tx_packet_recv (according to RFC 4340, 11.4 this can happen up to
    16192 times per Ack Vector).

 3) The RTO timer should not be restarted when all outstanding data has been
    acknowledged. This is currently done similar to (2), in dec_pipe, when
    pipe has reached 0.

The patch onsolidates the code which rearms the RTO timer, combining the
segments from new_ack and dec_pipe. As a result, the code becomes clearer
(compare with tcp_rearm_rto()).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23 20:13:31 -07:00
Gerrit Renker
30564e3555 dccp ccid-2: Remove redundant sanity tests
This removes the ccid2_hc_tx_check_sanity function: it is redundant.

Details:

The tx_check_sanity function performs three tests:
 1) it checks that the circular TX list is sorted
    - in ascending order of sequence number (ccid2s_seq)
    - and time (ccid2s_sent),
    - in the direction from `tail' (hctx_seqt) to `head' (hctx_seqh);
 2) it ensures that the entire list has the length seqbufc * CCID2_SEQBUF_LEN;
 3) it ensures that pipe equals the number of packets that were not
    marked `acked' (ccid2s_acked) between `tail' and `head'.

The following argues that each of these tests is redundant, this can be verified
by going through the code.

(1) is not necessary, since both time and GSS increase from one packet to the
next, so that subsequent insertions in tx_packet_sent (which advance the `head'
pointer) will be in ascending order of time and sequence number.

In (2), the length of the list is always equal to seqbufc times CCID2_SEQBUF_LEN
(set to 1024) unless allocation caused an earlier failure, because:
 * at initialisation (tx_init), there is one chunk of size 1024 and seqbufc=1;
 * subsequent calls to tx_alloc_seq take place whenever head->next == tail in
   tx_packet_sent; then a new chunk of size 1024 is inserted between head and
   tail, and seqbufc is incremented by one.

To show that (3) is redundant requires looking at two cases.

The `pipe' variable of the TX socket is incremented only in tx_packet_sent, and
decremented in tx_packet_recv.  When head == tail (TX history empty) then pipe
should be 0, which is the case directly after initialisation and after a
retransmission timeout has occurred (ccid2_hc_tx_rto_expire).

The first case involves parsing Ack Vectors for packets recorded in the live
portion of the buffer, between tail and head. For each packet marked by the
receiver as received (state 0) or ECN-marked (state 1), pipe is decremented by
one, so for all such packets the BUG_ON in tx_check_sanity will not trigger.

The second case is the loss detection in the second half of tx_packet_recv,
below the comment "Check for NUMDUPACK".

The first while-loop here ensures that the sequence number of `seqp' is either
above or equal to `high_ack', or otherwise equal to the highest sequence number
sent so far (of the entry head->prev, as head points to the next unsent entry).
The next while-loop ("while (1)") counts the number of acked packets starting
from that position of seqp, going backwards in the direction from head->prev to
tail. If NUMDUPACK=3 such packets were counted within this loop, `seqp' points
to the last acknowledged packet of these, and the "if (done == NUMDUPACK)" block
is entered next.
The while-loop contained within that block in turn traverses the list backwards,
from head to tail; the position of `seqp' is saved in the variable `last_acked'.
For each packet not marked as `acked', a congestion event is triggered within
the loop, and pipe is decremented. The loop terminates when `seqp' has reached
`tail', whereupon tail is set to the position previously stored in `last_acked'.
Thus, between `last_acked' and the previous position of `tail',
 - pipe has been decremented earlier if the packet was marked as state 0 or 1;
 - pipe was decremented if the packet was not marked as acked.
That is, pipe has been decremented by the number of packets between `last_acked'
and the previous position of `tail'. As a consequence, pipe now again reflects
the number of packets which have not (yet) been acked between the new position
of tail (at `last_acked') and head->prev, or 0 if head==tail. The result is that
the BUG_ON condition in check_sanity will also not be triggered, hence the test
(3) is also redundant.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23 20:13:30 -07:00
Gerrit Renker
51c22bb510 dccp ccid-3: No more CCID control blocks in LISTEN state
The CCIDs are activated as last of the features, at the end of the handshake,
were the LISTEN state of the master socket is inherited into the server
state of the child socket. Thus, the only states visible to CCIDs now are
OPEN/PARTOPEN, and the closing states.

This allows to remove tests which were previously necessary to protect
against referencing a socket in the listening state (in CCID-3), but which
now have become redundant.

As a further byproduct of enabling the CCIDs only after the connection has been
fully established, several typecast-initialisations of ccid3_hc_{rx,tx}_sock
can now be eliminated:
 * the CCID is loaded, so it is not necessary to test if it is NULL,
 * if it is possible to load a CCID and leave the private area NULL, then this
    is a bug, which should crash loudly - and earlier,
 * the test for state==OPEN || state==PARTOPEN now reduces only to the closing
   phase (e.g. when the node has received an unexpected Reset).

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>
2010-08-23 20:13:30 -07:00
Gerrit Renker
67b67e365f ccid: ccid-2/3 code cosmetics
This patch collects cosmetics-only changes to separate these from
code changes:
 * update with regard to CodingStyle and whitespace changes,
 * documentation:
   - adding/revising comments,
   - remove CCID-3 RX socket documentation which is either
     duplicate or refers to fields that no longer exist,
 * expand embedded tfrc_tx_info struct inline for consistency,
   removing indirections via #define.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23 20:13:29 -07:00
David S. Miller
21dc330157 net: Rename skb_has_frags to skb_has_frag_list
SKBs can be "fragmented" in two ways, via a page array (called
skb_shinfo(skb)->frags[]) and via a list of SKBs (called
skb_shinfo(skb)->frag_list).

Since skb_has_frags() tests the latter, it's name is confusing
since it sounds more like it's testing the former.

Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-23 00:13:46 -07:00
Hagen Paul Pfeifer
e88c64f0a4 tcp: allow effective reduction of TCP's rcv-buffer via setsockopt
Via setsockopt it is possible to reduce the socket RX buffer
(SO_RCVBUF). TCP method to select the initial window and window scaling
option in tcp_select_initial_window() currently misbehaves and do not
consider a reduced RX socket buffer via setsockopt.

Even though the server's RX buffer is reduced via setsockopt() to 256
byte (Initial Window 384 byte => 256 * 2 - (256 * 2 / 4)) the window
scale option is still 7:

192.168.1.38.40676 > 78.47.222.210.5001: Flags [S], seq 2577214362, win 5840, options [mss 1460,sackOK,TS val 338417 ecr 0,nop,wscale 0], length 0
78.47.222.210.5001 > 192.168.1.38.40676: Flags [S.], seq 1570631029, ack 2577214363, win 384, options [mss 1452,sackOK,TS val 2435248895 ecr 338417,nop,wscale 7], length 0
192.168.1.38.40676 > 78.47.222.210.5001: Flags [.], ack 1, win 5840, options [nop,nop,TS val 338421 ecr 2435248895], length 0

Within tcp_select_initial_window() the original space argument - a
representation of the rx buffer size - is expanded during
tcp_select_initial_window(). Only sysctl_tcp_rmem[2], sysctl_rmem_max
and window_clamp are considered to calculate the initial window.

This patch adjust the window_clamp argument if the user explicitly
reduce the receive buffer.

Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-08-22 21:42:54 -07:00