10048 Commits

Author SHA1 Message Date
Emmanuel Grumbach
8e1535d51b mac80211: Fix rate scale initialization in IBSS
This patch address some IBSS rate issues introduced or not covered
by "mac80211: eliminate IBSS warning in rate_lowest_index()" and
"cfg80211 API for channels/bitrates, mac80211 and driver conversion".

This patch:
1. Moves addition of IBSS station from
prepare_for_handlers to ieee80211_rx_bss_info when triggered from beacon
eliminating bogus supported rates.
2. Initialize properly supported rates also in IBSS merging
3. Ensure that mandatory rates are always added into supported
rates. This is needed in case when station addition is triggered from
non beacon/probe packet. Some management frames need to be sent
4. Remove initialization of supported rates from self rates. This path
was dead code after 6bc37c06bc4 and in general incorrect.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Cc: Vladimir Koutny <vlado@work.ksp.sk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-09-08 14:22:46 -04:00
Tomas Winkler
9818babc8f mac80211: Fix low bit rate in IBSS
This patch fixes regression in iwlwifi IBSS rate scaling caused by patch:

    commit 6bc37c06bc424bcf3f944e6a79e2d5bb537e02ed
    Author: Vladimir Koutny <vlado@work.ksp.sk>
    Date:   Fri Jun 13 16:50:44 2008 +0200

        mac80211: eliminate IBSS warning in rate_lowest_index()

An IBSS station is added in prepare_for_handlers where the rate scaling was
initialized only with single rate matching the received packet.
The correct rate scale information should be updated only in
ieee80211_rx_bss_info function where beacon is parsed. Because
of coding error the rate info was left untouched.
If a beacon has triggered the connection the rate remined 1Mbps.
This patch fixes this coding error

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Cc: Vladimir Koutny <vlado@work.ksp.sk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-09-08 14:00:18 -04:00
Jarek Poplawski
e8a83e10d7 pkt_sched: Fix qdisc state in net_tx_action()
net_tx_action() can skip __QDISC_STATE_SCHED bit clearing while qdisc
is neither ran nor rescheduled, which may cause endless loop in
dev_deactivate().

Reported-by: Denys Fedoryshchenko <denys@visp.net.lb>
Tested-by: Denys Fedoryshchenko <denys@visp.net.lb>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-07 18:41:21 -07:00
Patrick McHardy
e3b802ba88 netfilter: nf_conntrack_irc: make sure string is terminated before calling simple_strtoul
Alexey Dobriyan points out:

1. simple_strtoul() silently accepts all characters for given base even
   if result won't fit into unsigned long. This is amazing stupidity in
   itself, but

2. nf_conntrack_irc helper use simple_strtoul() for DCC request parsing.
   Data first copied into 64KB buffer, so theoretically nothing prevents
   reading past the end of it, since data comes from network given 1).

This is not actually a problem currently since we're guaranteed to have
a 0 byte in skb_shared_info or in the buffer the data is copied to, but
to make this more robust, make sure the string is actually terminated.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-07 18:21:24 -07:00
Alexey Dobriyan
51807e91a7 netfilter: nf_conntrack_gre: nf_ct_gre_keymap_flush() fixlet
It does "kfree(list_head)" which looks wrong because entity that was
allocated is definitely not list_head.

However, this all works because list_head is first item in
struct nf_ct_gre_keymap.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-07 18:20:36 -07:00
Alexey Dobriyan
887464a41f netfilter: nf_conntrack_gre: more locking around keymap list
gre_keymap_list should be protected in all places.
(unless I'm misreading something)

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-07 18:20:08 -07:00
Alexey Dobriyan
66bf79182d netfilter: nf_conntrack_sip: de-static helper pointers
Helper's ->help hook can run concurrently with itself, so iterating over
SIP helpers with static pointer won't work reliably.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2008-09-07 18:19:25 -07:00
Simon Horman
178f5e494e IPVS: use ipv6_addr_copy()
It is standard to use ipv6_addr_copy() to fill in
the in6 element of a union nf_inet_addr snet.

Thanks to Julius Volz for pointing this out.

Cc: Brian Haley <brian.haley@hp.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: Julius Volz <juliusv@google.com>
2008-09-08 09:34:46 +10:00
Simon Horman
5af149cc34 IPVS: fix bogus indentation
Sorry, this was my error.
Thanks to Julius Volz for pointing it out.

Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: Julius Volz <juliusv@google.com>
2008-09-08 09:34:45 +10:00
Sven Wegener
3bfb92f407 ipvs: Reject ipv6 link-local addresses for destinations
We can't use non-local link-local addresses for destinations, without
knowing the interface on which we can reach the address. Reject them for
now.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-08 09:34:45 +10:00
Sven Wegener
77eb851630 ipvs: Mark tcp/udp v4 and v6 debug functions static
They are only used in this file, so they should be static

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-08 09:34:44 +10:00
Sven Wegener
a5ba4bf273 ipvs: Return negative error values from ip_vs_edit_service()
Like the other code in this function does.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-08 09:34:44 +10:00
Sven Wegener
cd9fe6c4f0 ipvs: Use pointer to address from sync message
We want a pointer to it, not the value casted to a pointer.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-08 09:34:43 +10:00
Luis R. Rodriguez
f59ac04816 cfg80211: keep track of supported interface modes
It is obviously good for userspace to know up front which
interface modes a given piece of hardware might support (even
if adding such an interface might fail later because of
concurrency issues), so let's make cfg80211 aware of that.
For good measure, disallow adding interfaces in all other
modes so drivers don't forget to announce support for one mode
when they add it.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Stephen Blackheath <tramp.enshrine.stephen@blacksapphire.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2008-09-05 16:17:42 -04:00
Linus Torvalds
bf7394ccc1 Revert "mac80211: Use IWEVASSOCREQIE instead of IWEVCUSTOM"
This reverts commit 087d833e5a9f67ba933cb32eaf5a2279c1a5b47c, which was
reported to break wireless at least in some combinations with 32bit user
space and a 64bit kernel.  Alex Williamnson bisected it to this commit.

Reported-and-bisected-by: Alex Williamson <alex.williamson@hp.com>
Acked-by: John W. Linville <linville@tuxdriver.com>
Cc: David Miller <davem@davemloft.net>
Cc: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-05 12:38:09 -07:00
Simon Horman
f2428ed5e7 ipvs: load balance ipv6 connections from a local process
This allows IPVS to load balance IPv6 connections made by a local process.
For example a proxy server running locally.

External client --> pound:443 -> Local:443 --> IPVS:80 --> RealServer

This is an extenstion to the IPv4 work done in this area
by Siim Põder and Malcolm Turnbull.

Cc: Siim Põder <siim@p6drad-teel.net>
Cc: Malcolm Turnbull <malcolm@loadbalancer.org>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:14 +10:00
Malcolm Turnbull
4856c84c13 ipvs: load balance IPv4 connections from a local process
This allows IPVS to load balance connections made by a local process.
For example a proxy server running locally.

External client --> pound:443 -> Local:443 --> IPVS:80 --> RealServer

Signed-off-by: Siim Põder <siim@p6drad-teel.net>
Signed-off-by: Malcolm Turnbull <malcolm@loadbalancer.org>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:13 +10:00
Julius Volz
f94fd04140 IPVS: Allow adding IPv6 services from userspace
Allow adding IPv6 services through the genetlink interface and add checks
to see if the chosen scheduler is supported with IPv6 and whether the
supplied prefix length is sane. Make sure the service count exported via
the sockopt interface only counts IPv4 services.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:13 +10:00
Julius Volz
473b23d37b IPVS: Activate IPv6 Netfilter hooks
Register the previously defined or adapted netfilter hook functions for
IPv6 as PF_INET6 hooks.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:13 +10:00
Julius Volz
cfc78c5a09 IPVS: Adjust various debug outputs to use new macros
Adjust various debug outputs to use the new *_BUF macro variants for
correct output of v4/v6 addresses.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:12 +10:00
Vince Busam
09571c7ae3 IPVS: Add function to determine if IPv6 address is local
Add __ip_vs_addr_is_local_v6() to find out if an IPv6 address belongs to a
local interface. Use this function to decide whether to set the
IP_VS_CONN_F_LOCALNODE flag for IPv6 destinations.

Signed-off-by: Vince Busam <vbusam@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:12 +10:00
Julius Volz
a0eb662f9e IPVS: Turn off FTP application helper for IPv6
Immediately return from FTP application helper and do nothing when dealing
with IPv6 packets. IPv6 is not supported by this helper yet.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:11 +10:00
Julius Volz
c6883f5873 IVPS: Disable sync daemon for IPv6 connections
Disable the sync daemon for IPv6 connections, works only with IPv4 for now.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:11 +10:00
Vince Busam
667a5f1816 IPVS: Convert procfs files for IPv6 entry output
Correctly output IPv6 connection/service/dest entries in procfs files.

Signed-off-by: Vince Busam <vbusam@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:10 +10:00
Julius Volz
7937df1564 IPVS: Convert real server lookup functions
Convert functions for looking up destinations (real servers) to support
IPv6 services/dests.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:10 +10:00
Julius Volz
2a3b791e6e IPVS: Add/adjust Netfilter hook functions and helpers for v6
Add Netfilter hook functions or modify existing ones, if possible, to
process IPv6 packets. Some support functions are also added/modified for
this. ip_vs_nat_icmp_v6() was already added in the patch that added the v6
xmit functions, as it is called from one of them.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:09 +10:00
Julius Volz
cd17f9ed09 IPVS: Extend scheduling functions for IPv6 support
Convert ip_vs_schedule() and ip_vs_sched_persist() to support scheduling of
IPv6 connections.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:09 +10:00
Julius Volz
b3cdd2a738 IPVS: Add and bind IPv6 xmit functions
Add xmit functions for IPv6. Also add the already needed __ip_vs_get_out_rt_v6()
to ip_vs_core.c. Bind the new xmit functions to v6 connections.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:08 +10:00
Julius Volz
38cdcc9a03 IPVS: Add IPv6 support to xmit() support functions
Add IPv6 support to IP_VS_XMIT() and to the xmit routing cache, introducing
a new function __ip_vs_get_out_rt_v6().

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:08 +10:00
Julius Volz
28364a59f3 IPVS: Extend functions for getting/creating connections
Extend functions for getting/creating connections and connection
templates for IPv6 support and fix the callers.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:08 +10:00
Julius Volz
0bbdd42b7e IPVS: Extend protocol DNAT/SNAT and state handlers
Extend protocol DNAT/SNAT and state handlers to work with IPv6. Also
change/introduce new checksumming helper functions for this.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:07 +10:00
Julius Volz
3b047d9d04 IPVS: Add protocol debug functions for IPv6
Add protocol (TCP, UDP, AH, ESP) debug functions for IPv6 packet debug
output.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:06 +10:00
Julius Volz
51ef348b14 IPVS: Add 'af' args to protocol handler functions
Add 'af' arguments to conn_schedule(), conn_in_get(), conn_out_get() and
csum_check() function pointers in struct ip_vs_protocol. Extend the
respective functions for TCP, UDP, AH and ESP and adjust the callers.

The changes in the callers need to be somewhat extensive, since they now
need to pass a filled out struct ip_vs_iphdr * to the modified functions
instead of a struct iphdr *.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:06 +10:00
Julius Volz
b14198f6c1 IPVS: Add IPv6 support flag to schedulers
Add 'supports_ipv6' flag to struct ip_vs_scheduler to indicate whether a
scheduler supports IPv6. Set the flag to 1 in schedulers that work with
IPv6, 0 otherwise. This flag is checked in a later patch while trying to
add a service with a specific scheduler. Adjust debug in v6-supporting
schedulers to work with both address families.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:06 +10:00
Julius Volz
3c2e0505d2 IPVS: Add v6 support to ip_vs_service_get()
Add support for selecting services based on their address family to
ip_vs_service_get() and adjust the callers.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:05 +10:00
Julius Volz
b18610de9e IPVS: Convert __ip_vs_svc_get() and __ip_vs_fwm_get()
Add support for getting services based on their address family to
__ip_vs_service_get(), __ip_vs_fwm_get() and the helper hash function
ip_vs_svc_hashkey(). Adjust the callers.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:05 +10:00
Julius Volz
c860c6b147 IPVS: Add internal versions of sockopt interface structs
Add extended internal versions of struct ip_vs_service_user and struct
ip_vs_dest_user (the originals can't be modified as they are part
of the old sockopt interface). Adjust ip_vs_ctl.c to work with the new
data structures and add some minor AF-awareness.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:04 +10:00
Julius Volz
e7ade46a53 IPVS: Change IPVS data structures to support IPv6 addresses
Introduce new 'af' fields into IPVS data structures for specifying an
entry's address family. Convert IP addresses to be of type union
nf_inet_addr.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:03 +10:00
Julius Volz
fab0de02fb IPVS: Add CONFIG_IP_VS_IPV6 option for IPv6 support
Add boolean config option CONFIG_IP_VS_IPV6 for enabling experimental IPv6
support in IPVS. Only visible if IPv6 support is set to 'y' or both IPv6
and IPVS are modules.

Signed-off-by: Julius Volz <juliusv@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
2008-09-05 11:17:02 +10:00
Gerrit Renker
a3cbdde8e9 dccp ccid-3: Preventing Oscillations
This implements [RFC 3448, 4.5], which performs congestion avoidance behaviour
by reducing the transmit rate as the queueing delay (measured in terms of
long-term RTT) increases.

Oscillation can be turned on/off via a module option (do_osc_prev) and via sysfs
(using mode 0644), the default is off.

Overflow analysis:
------------------
 * oscillation prevention is done after update_x(), so that t_ipi <= 64000;
 * hence the multiplication "t_ipi * sqrt(R_sample)" needs 64 bits;
 * done using u64 for sqrt_sample and explicit typecast of t_ipi;
 * the divisor, R_sqmean, is non-zero because oscillation prevention is first
   called when receiving the second feedback packet, and tfrc_scaled_rtt() > 0.

A detailed discussion of the algorithm (with plots) is on
http://www.erg.abdn.ac.uk/users/gerrit/dccp/notes/ccid3/sender_notes/oscillation_prevention/

The algorithm has negative side effects:
  * when allowing to decrease t_ipi (leads to a large RTT) and
  * when using it during slow-start;
both uses are therefore disabled.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:43 +02:00
Gerrit Renker
53ac9570c8 dccp ccid-3: Simplify computing and range-checking of t_ipi
This patch simplifies the computation of t_ipi, avoiding expensive computations
to enforce the minimum sending rate.

Both RFC 3448 and rfc3448bis (revision #06), as well as RFC 4342 sec 5., require
at various stages that at least one packet must be sent per t_mbi = 64 seconds.
This requires frequent divisions of the type X_min = s/t_mbi, which are later
converted back into an inter-packet-interval t_ipi_max = s/X_min = t_mbi.

The patch removes the expensive indirection; in the unlikely case of having
a sending rate less than one packet per 64 seconds, it also re-adjusts X.

The following cases document conformance with RFC 3448  / rfc3448bis-06:
 1) Time until receiving the first feedback packet:
   * if the sender has no initial RTT sample then X = s/1 Bps > s/t_mbi;
   * if the sender has an initial RTT sample or when the first feedback
     packet is received, X = W_init/R > s/t_mbi.

 2) Slow-start (p == 0 and feedback packets come in):
   * RFC 3448  (current code) enforces a minimum of s/R > s/t_mbi;
   * rfc3448bis (future code) enforces an even higher minimum of W_init/R.

 3) Congestion avoidance with no absence of feedback (p > 0):
   * when X_calc or X_recv/2 are too low, the minimum of X_min = s/t_mbi
     is enforced in update_x() when calling update_send_interval();
   * update_send_interval() is, as before, only called when X changes
     (i.e. either when increasing or decreasing, not when in equilibrium).

 4) Reduction of X without prior feedback or during slow-start (p==0):
   * both RFC 3448 and rfc3448bis here halve X directly;
   * the associated constraint X >= s/t_mbi is nforced here by send_interval().

 5) Reduction of X when p > 0:
   * X is modified indirectly via X_recv (RFC 3448) or X_recv_set (rfc3448bis);
   * in both cases, control goes back to section 4.3 (in both documents);
   * since p > 0, both documents use X = max(min(...), s/t_mbi), which is
     enforced in this patch by calling send_interval() from update_x().

I think that this analysis is exhaustive. Should I have forgotten a case,
the worst-case consideration arises when X sinks below s/t_mbi, and is then
increased back up to this minimum value. Even under this assumption, the
behaviour is correct, since all lower limits of X in RFC 3448 / rfc3448bis
are either equal to or greater than s/t_mbi.

Note on the condition X >= s/t_mbi  <==> t_ipi = s/X <= t_mbi: since X is
scaled by 64, and all time units are in microseconds, the coded condition is:

    t_ipi = s * 64 * 10^6 usec / X <= 64 * 10^6 usec

This simplifies to s / X <= 1 second <==> X * 1 second >= s > 0.
(A zero `s' is not allowed by the CCID-3 code).	

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:43 +02:00
Gerrit Renker
c8f41d50ad dccp ccid-3: Measuring the packet size s with regard to rfc3448bis-06
rfc3448bis allows three different ways of tracking the packet size `s': 

 1. using the MSS/MPS (at initialisation, 4.2, and in 4.1 (1));
 2. using the average of `s' (in 4.1);
 3. using the maximum of `s' (in 4.2).

Instead of hard-coding a single interpretation of rfc3448bis, this implements
a choice of all three alternatives and suggests the first as default, since it
is the option which is most consistent with other parts of the specification.

The patch further deprecates the update of t_ipi whenever `s' changes. The
gains of doing this are only small since a change of s takes effect at the
next instant X is updated:
 * when the next feedback comes in (within one RTT or less);
 * when the nofeedback timer expires (within at most 4 RTTs).
 
Further, there are complications caused by updating t_ipi whenever s changes:
 * if t_ipi had previously been updated to effect oscillation prevention (4.5),
   then it is impossible to make the same adjustment to t_ipi again, thus
   counter-acting the algorithm;
 * s may be updated any time and a modification of t_ipi depends on the current
   state (e.g. no oscillation prevention is done in the absence of feedback);
 * in rev-06 of rfc3448bis, there are more possible cases, depending on whether
   the sender is in slow-start (t_ipi <= R/W_init), or in congestion-avoidance,
   limited by X_recv or the throughput equation (t_ipi <= t_mbi).

Thus there are side effects of always updating t_ipi as s changes. These may not
be desirable. The only case I can think of where such an update makes sense is
to recompute X_calc when p > 0 and when s changes (not done by this patch).

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:42 +02:00
Gerrit Renker
891e4d8a40 dccp ccid-3: Tidy up CCID-Kconfig dependencies
The per-CCID menu has several dependencies on EXPERIMENTAL. These are redundant,
since net/dccp/ccids/Kconfig is sourced by net/dccp/Kconfig and since the
latter menu in turn asserts a dependency on EXPERIMENTAL.

The patch removes the redundant dependencies as well as the repeated reference
within the sub-menu.

Further changes:
----------------
Two single dependencies on CCID-3 are replaced with a single enclosing `if'.
    
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:42 +02:00
Gerrit Renker
9d497a2c91 dccp ccid-3: Implement rfc3448bis change to initial-rate computation
The patch updates CCID-3 with regard to the latest rfc3448bis-06: 
 * in the first revisions of the draft, MSS was used for the RFC 3390 window; 
 * then (from revision #1 to revision #2), it used the packet size `s';
 * now, in this revision (and apparently final), the value is back to MSS.

This change has an implication for the case when no RTT sample is available,
at the time of sending the first packet:

 * with RTT sample, 2*MSS/RTT <= initial_rate <= 4*MSS/RTT;
 * without RTT sample, the initial rate is one packet (s bytes) per second
   (sec. 4.2), but using s instead of MSS here creates an imbalance, since
   this would further reduce the initial sending rate.

Hence the patch uses MSS (called MPS in RFC 4340) in all places.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:42 +02:00
Gerrit Renker
88e97a9334 dccp ccid-3: Update the RX history records in one place
This patch is a requirement for enabling ECN support later on. With that change
in mind, the following preparations are done:
 * renamed handle_loss() into congestion_event() since it returns true when a
   congestion event happens (it will eventually also take care of ECN packets);
 * lets tfrc_rx_congestion_event() always update the RX history records, since
   this routine needs to be called for each non-duplicate packet anyway;
 * made all involved boolean-type functions to have return type `bool';

Updating the RX history records is now only necessary for the packets received
up to sending the first feedback. The receiver code becomes again simpler.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:42 +02:00
Gerrit Renker
68c89ee535 dccp ccid-3: Update the computation of X_recv
This updates the computation of X_recv with regard to Errata 610/611 for
RFC 4342 and draft rfc3448bis-06, ensuring that at least an interval of 1
RTT is used to compute X_recv.  The change is wrapped into a new function
ccid3_hc_rx_x_recv().

Further changes:
----------------
 * feedback is not sent when no data packets arrived (bytes_recv == 0), as per
   rfc3448bis-06, 6.2;
 * take the timestamp for the feedback /after/ dccp_send_ack() returns, to avoid
   taking the transmission time into account (in case layer-2 is busy);
 * clearer handling of failure in ccid3_first_li().

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:42 +02:00
Gerrit Renker
22338f09bd dccp tfrc: Increase number of RTT samples
This improves the receiver RTT sampling algorithm so that it tries harder to get
as many RTT samples as possible. 

The algorithm is based the concepts presented in RFC 4340, 8.1, using timestamps
and the CCVal window counter. There exist 4 cases for the CCVal difference:
 * == 0: less than RTT/4 passed since last packet -- unusable;
 *  > 4: (much) more than 1 RTT has passed since last packet -- also unusable;
 * == 4: perfect sample (exactly one RTT has passed since last packet);
 * 1..3: sub-optimal sample (between RTT/4 and 3*RTT/4 has passed).

In the last case the algorithm tried to optimise by storing away the candidate
and then re-trying next time. The problem is that
 * a large number of samples is needed to smooth out the inaccuracies of the
   algorithm;
 * the sender may not be sending enough packets to warrant a "next time";
 * hence it is better to use suboptimal samples whenever possible.
The algorithm now stores away the current sample only if the difference is 0.

Applicability and background
----------------------------
A realistic example is MP3 streaming where packets are sent at a rate of less
than one packet per RTT, which means that suitable samples are absent for a
very long time.

The effectiveness of using suboptimal samples (with a delta between 1 and 4) was
confirmed by instrumenting the algorithm with counters. The results of two 20
second test runs were:
 * With the old algorithm and a total of 38442 function calls, only 394 of these
   calls resulted in usable RTT samples (about 1%), and 378 out of these were
   "perfect" samples and 28013 (unused) samples had a delta of 1..3.
 * With the new algorithm and a total of 37057 function calls, 1702 usable RTT
   samples were retrieved (about 4.6%), 5 out of these were "perfect" samples.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:42 +02:00
Gerrit Renker
49ffc29a02 dccp: Clamping RTT values
This extracts the clamping part of dccp_sample_rtt() and makes it available
to other parts of the code (as e.g. used in the next patch).

Note: The function dccp_sample_rtt() now reduces to subtracting the elapsed
time. This could be eliminated but would require shorter prefixes and thus
is not done by this patch - maybe an idea for later.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:41 +02:00
Gerrit Renker
2b81143aa3 dccp ccid-3: Always perform receiver RTT sampling
This updates the CCID-3 receiver in part with regard to errata 610 and 611
(http://www.rfc-editor.org/errata_list.php), which change RFC 4342 to use the
Receive Rate as specified in rfc3448bis, requiring to constantly sample the
RTT (or use a sender RTT).

Doing this requires reusing the RX history structure after dealing with a loss.

The patch does not resolve how to compute X_recv if the interval is less
than 1 RTT. A FIXME has been added (and is resolved in subsequent patch).

Furthermore, since this is all TFRC-based functionality, the RTT estimation
is now also performed by the dccp_tfrc_lib module. This further simplifies
the CCID-3 code.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:41 +02:00
Gerrit Renker
2f3e3bbad9 dccp ccid-3: Remove duplicate RX states
The only state information that the CCID-3 receiver keeps is whether initial 
feedback has been sent or not. Further, this overlaps with use of feedback:

 * state == TFRC_RSTATE_NO_DATA as long as no feedback has been sent;
 * state == TFRC_RSTATE_DATA    as soon as the first feedback has been sent.

This patch reduces the duplication, by memorising the type of the last feedback.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
2008-09-04 07:45:41 +02:00